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21  <title>PALM chapter 4.1</title></head>
22<body>
23
24
25
26
27<h3><a name="chapter4.1"></a>4.1
28Initialization parameters</h3>
29
30
31
32
33
34<br>
35
36
37
38
39<table style="text-align: left; width: 100%;" border="1" cellpadding="2" cellspacing="2">
40
41
42
43
44 <tbody>
45
46
47
48
49
50    <tr>
51
52
53
54
55 <td style="vertical-align: top;"><font size="4"><b>Parameter name</b></font></td>
56
57
58
59
60
61      <td style="vertical-align: top;"><font size="4"><b>Type</b></font></td>
62
63
64
65
66
67      <td style="vertical-align: top;"> 
68     
69     
70     
71     
72      <p><b><font size="4">Default</font></b> <br>
73
74
75
76
77 <b><font size="4">value</font></b></p>
78
79
80
81
82 </td>
83
84
85
86
87
88      <td style="vertical-align: top;"><font size="4"><b>Explanation</b></font></td>
89
90
91
92
93
94    </tr>
95
96
97
98
99 <tr>
100
101
102
103
104 <td style="vertical-align: top;">
105     
106     
107     
108     
109      <p><a name="adjust_mixing_length"></a><b>adjust_mixing_length</b></p>
110
111
112
113
114
115      </td>
116
117
118
119
120 <td style="vertical-align: top;">L</td>
121
122
123
124
125
126      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
127
128
129
130
131 <td style="vertical-align: top;"> 
132     
133     
134     
135     
136      <p style="font-style: normal;">Near-surface adjustment of the
137mixing length to the Prandtl-layer law.&nbsp; </p>
138
139
140
141
142 
143     
144     
145     
146     
147      <p>Usually
148the mixing length in LES models l<sub>LES</sub>
149depends (as in PALM) on the grid size and is possibly restricted
150further in case of stable stratification and near the lower wall (see
151parameter <a href="#wall_adjustment">wall_adjustment</a>).
152With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span>
153the Prandtl' mixing length l<sub>PR</sub> = kappa * z/phi
154is calculated
155and the mixing length actually used in the model is set l = MIN (l<sub>LES</sub>,
156l<sub>PR</sub>). This usually gives a decrease of the
157mixing length at
158the bottom boundary and considers the fact that eddy sizes
159decrease in the vicinity of the wall.&nbsp; </p>
160
161
162
163
164 
165     
166     
167     
168     
169      <p style="font-style: normal;"><b>Warning:</b> So
170far, there is
171no good experience with <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> !&nbsp; </p>
172
173
174
175
176
177     
178     
179     
180     
181      <p>With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> and the
182Prandtl-layer being
183switched on (see <a href="#prandtl_layer">prandtl_layer</a>)
184      <span style="font-style: italic;">'(u*)** 2+neumann'</span>
185should always be set as the lower boundary condition for the TKE (see <a href="#bc_e_b">bc_e_b</a>),
186otherwise the near-surface value of the TKE is not in agreement with
187the Prandtl-layer law (Prandtl-layer law and Prandtl-Kolmogorov-Ansatz
188should provide the same value for K<sub>m</sub>). A warning
189is given,
190if this is not the case.</p>
191
192
193
194
195 </td>
196
197
198
199
200 </tr>
201
202
203
204
205 <tr>
206
207
208
209
210
211      <td style="vertical-align: top;"> 
212     
213     
214     
215     
216      <p><a name="alpha_surface"></a><b>alpha_surface</b></p>
217
218
219
220
221
222      </td>
223
224
225
226
227 <td style="vertical-align: top;">R<br>
228
229
230
231
232 </td>
233
234
235
236
237
238      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
239
240
241
242
243 </td>
244
245
246
247
248
249      <td style="vertical-align: top;"> 
250     
251     
252     
253     
254      <p style="font-style: normal;">Inclination of the model domain
255with respect to the horizontal (in degrees).&nbsp; </p>
256
257
258
259
260 
261     
262     
263     
264     
265      <p style="font-style: normal;">By means of <b>alpha_surface</b>
266the model domain can be inclined in x-direction with respect to the
267horizontal. In this way flows over inclined surfaces (e.g. drainage
268flows, gravity flows) can be simulated. In case of <b>alpha_surface
269      </b>/= <span style="font-style: italic;">0</span>
270the buoyancy term
271appears both in
272the equation of motion of the u-component and of the w-component.<br>
273
274
275
276
277
278      </p>
279
280
281
282
283 
284     
285     
286     
287     
288      <p style="font-style: normal;">An inclination
289is only possible in
290case of cyclic horizontal boundary conditions along x AND y (see <a href="#bc_lr">bc_lr</a>
291and <a href="#bc_ns">bc_ns</a>) and <a href="#topography">topography</a> = <span style="font-style: italic;">'flat'</span>. </p>
292
293
294
295
296
297     
298     
299     
300     
301      <p>Runs with inclined surface still require additional
302user-defined code as well as modifications to the default code. Please
303ask the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/PALM_group.html#0">PALM
304developer&nbsp; group</a>.</p>
305
306
307
308
309 </td>
310
311
312
313
314 </tr>
315
316
317
318
319
320    <tr>
321
322
323
324
325 <td style="vertical-align: top;"> 
326     
327     
328     
329     
330      <p><a name="bc_e_b"></a><b>bc_e_b</b></p>
331
332
333
334
335 </td>
336
337
338
339
340
341      <td style="vertical-align: top;">C * 20</td>
342
343
344
345
346 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
347
348
349
350
351
352      <td style="vertical-align: top;"> 
353     
354     
355     
356     
357      <p style="font-style: normal;">Bottom boundary condition of the
358TKE.&nbsp; </p>
359
360
361
362
363 
364     
365     
366     
367     
368      <p><b>bc_e_b</b> may be
369set to&nbsp;<span style="font-style: italic;">'neumann'</span>
370or <span style="font-style: italic;">'(u*) ** 2+neumann'</span>.
371      <b>bc_e_b</b>
372= <span style="font-style: italic;">'neumann'</span>
373yields to
374e(k=0)=e(k=1) (Neumann boundary condition), where e(k=1) is calculated
375via the prognostic TKE equation. Choice of <span style="font-style: italic;">'(u*)**2+neumann'</span>
376also yields to
377e(k=0)=e(k=1), but the TKE at the Prandtl-layer top (k=1) is calculated
378diagnostically by e(k=1)=(us/0.1)**2. However, this is only allowed if
379a Prandtl-layer is used (<a href="#prandtl_layer">prandtl_layer</a>).
380If this is not the case, a warning is given and <b>bc_e_b</b>
381is reset
382to <span style="font-style: italic;">'neumann'</span>.&nbsp;
383      </p>
384
385
386
387
388 
389     
390     
391     
392     
393      <p style="font-style: normal;">At the top
394boundary a Neumann
395boundary condition is generally used: (e(nz+1) = e(nz)).</p>
396
397
398
399
400 </td>
401
402
403
404
405
406    </tr>
407
408
409
410
411 <tr>
412
413
414
415
416 <td style="vertical-align: top;">
417     
418     
419     
420     
421      <p><a name="bc_lr"></a><b>bc_lr</b></p>
422
423
424
425
426
427      </td>
428
429
430
431
432 <td style="vertical-align: top;">C * 20</td>
433
434
435
436
437
438      <td style="vertical-align: top;"><span style="font-style: italic;">'cyclic'</span></td>
439
440
441
442
443
444      <td style="vertical-align: top;">Boundary
445condition along x (for all quantities).<br>
446
447
448
449
450 <br>
451
452
453
454
455
456By default, a cyclic boundary condition is used along x.<br>
457
458
459
460
461 <br>
462
463
464
465
466
467      <span style="font-weight: bold;">bc_lr</span> may
468also be
469assigned the values <span style="font-style: italic;">'dirichlet/radiation'</span>
470(inflow from left, outflow to the right) or <span style="font-style: italic;">'radiation/dirichlet'</span>
471(inflow from
472right, outflow to the left). This requires the multi-grid method to be
473used for solving the Poisson equation for perturbation pressure (see <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">psolver</a>)
474and it also requires cyclic boundary conditions along y (see&nbsp;<a href="#bc_ns">bc_ns</a>).<br>
475
476
477
478
479 <br>
480
481
482
483
484
485In case of these non-cyclic lateral boundaries, a Dirichlet condition
486is used at the inflow for all quantities (initial vertical profiles -
487see <a href="#initializing_actions">initializing_actions</a>
488- are fixed during the run) except u, to which a Neumann (zero
489gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
490gradient) condition is used for the scalars. For perturbation
491pressure Neumann (zero gradient) conditions are assumed both at the
492inflow and at the outflow.<br>
493
494
495
496
497 <br>
498
499
500
501
502
503When using non-cyclic lateral boundaries, a filter is applied to the
504velocity field in the vicinity of the outflow in order to suppress any
505reflections of outgoing disturbances (see <a href="#km_damp_max">km_damp_max</a>
506and <a href="#outflow_damping_width">outflow_damping_width</a>).<br>
507
508
509
510
511
512      <br>
513
514
515
516
517
518In order to maintain a turbulent state of the flow, it may be
519neccessary to continuously impose perturbations on the horizontal
520velocity field in the vicinity of the inflow throughout the whole run.
521This can be switched on using <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#create_disturbances">create_disturbances</a>.
522The horizontal range to which these perturbations are applied is
523controlled by the parameters <a href="#inflow_disturbance_begin">inflow_disturbance_begin</a>
524and <a href="#inflow_disturbance_end">inflow_disturbance_end</a>.
525The vertical range and the perturbation amplitude are given by <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_level_b</a>,
526      <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_level_t</a>,
527and <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_amplitude</a>.
528The time interval at which perturbations are to be imposed is set by <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#dt_disturb">dt_disturb</a>.<br>
529
530
531
532
533
534      <br>
535
536
537
538
539
540In case of non-cyclic horizontal boundaries <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#call_psolver_at_all_substeps">call_psolver
541at_all_substeps</a> = .T. should be used.<br>
542
543
544
545
546 <br>
547
548
549
550
551 <span style="font-weight: bold;">Note:</span><br>
552
553
554
555
556
557Using non-cyclic lateral boundaries requires very sensitive adjustments
558of the inflow (vertical profiles) and the bottom boundary conditions,
559e.g. a surface heating should not be applied near the inflow boundary
560because this may significantly disturb the inflow. Please check the
561model results very carefully.</td>
562
563
564
565
566 </tr>
567
568
569
570
571 <tr>
572
573
574
575
576 <td style="vertical-align: top;"> 
577     
578     
579     
580     
581      <p><a name="bc_ns"></a><b>bc_ns</b></p>
582
583
584
585
586
587      </td>
588
589
590
591
592 <td style="vertical-align: top;">C * 20</td>
593
594
595
596
597
598      <td style="vertical-align: top;"><span style="font-style: italic;">'cyclic'</span></td>
599
600
601
602
603
604      <td style="vertical-align: top;">Boundary
605condition along y (for all quantities).<br>
606
607
608
609
610 <br>
611
612
613
614
615
616By default, a cyclic boundary condition is used along y.<br>
617
618
619
620
621 <br>
622
623
624
625
626
627      <span style="font-weight: bold;">bc_ns</span> may
628also be
629assigned the values <span style="font-style: italic;">'dirichlet/radiation'</span>
630(inflow from rear ("north"), outflow to the front ("south")) or <span style="font-style: italic;">'radiation/dirichlet'</span>
631(inflow from front ("south"), outflow to the rear ("north")). This
632requires the multi-grid
633method to be used for solving the Poisson equation for perturbation
634pressure (see <a href="chapter_4.2.html#psolver">psolver</a>)
635and it also requires cyclic boundary conditions along x (see<br>
636
637
638
639
640 <a href="#bc_lr">bc_lr</a>).<br>
641
642
643
644
645 <br>
646
647
648
649
650
651In case of these non-cyclic lateral boundaries, a Dirichlet condition
652is used at the inflow for all quantities (initial vertical profiles -
653see <a href="chapter_4.1.html#initializing_actions">initializing_actions</a>
654- are fixed during the run) except u, to which a Neumann (zero
655gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
656gradient) condition is used for the scalars. For perturbation
657pressure Neumann (zero gradient) conditions are assumed both at the
658inflow and at the outflow.<br>
659
660
661
662
663 <br>
664
665
666
667
668
669For further details regarding non-cyclic lateral boundary conditions
670see <a href="#bc_lr">bc_lr</a>.</td>
671
672
673
674
675 </tr>
676
677
678
679
680
681    <tr>
682
683
684
685
686 <td style="vertical-align: top;"> 
687     
688     
689     
690     
691      <p><a name="bc_p_b"></a><b>bc_p_b</b></p>
692
693
694
695
696 </td>
697
698
699
700
701
702      <td style="vertical-align: top;">C * 20</td>
703
704
705
706
707 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
708
709
710
711
712
713      <td style="vertical-align: top;"> 
714     
715     
716     
717     
718      <p style="font-style: normal;">Bottom boundary condition of the
719perturbation pressure.&nbsp; </p>
720
721
722
723
724 
725     
726     
727     
728     
729      <p>Allowed values
730are <span style="font-style: italic;">'dirichlet'</span>,
731      <span style="font-style: italic;">'neumann'</span>
732and <span style="font-style: italic;">'neumann+inhomo'</span>.&nbsp;
733      <span style="font-style: italic;">'dirichlet'</span>
734sets
735p(k=0)=0.0,&nbsp; <span style="font-style: italic;">'neumann'</span>
736sets p(k=0)=p(k=1). <span style="font-style: italic;">'neumann+inhomo'</span>
737corresponds to an extended Neumann boundary condition where heat flux
738or temperature inhomogeneities near the
739surface (pt(k=1))&nbsp; are additionally regarded (see Shen and
740LeClerc
741(1995, Q.J.R. Meteorol. Soc.,
7421209)). This condition is only permitted with the Prandtl-layer
743switched on (<a href="#prandtl_layer">prandtl_layer</a>),
744otherwise the run is terminated.&nbsp; </p>
745
746
747
748
749 
750     
751     
752     
753     
754      <p>Since
755at the bottom boundary of the model the vertical
756velocity
757disappears (w(k=0) = 0.0), the consistent Neumann condition (<span style="font-style: italic;">'neumann'</span> or <span style="font-style: italic;">'neumann+inhomo'</span>)
758dp/dz = 0 should
759be used, which leaves the vertical component w unchanged when the
760pressure solver is applied. Simultaneous use of the Neumann boundary
761conditions both at the bottom and at the top boundary (<a href="#bc_p_t">bc_p_t</a>)
762usually yields no consistent solution for the perturbation pressure and
763should be avoided.</p>
764
765
766
767
768 </td>
769
770
771
772
773 </tr>
774
775
776
777
778 <tr>
779
780
781
782
783 <td style="vertical-align: top;"> 
784     
785     
786     
787     
788      <p><a name="bc_p_t"></a><b>bc_p_t</b></p>
789
790
791
792
793
794      </td>
795
796
797
798
799 <td style="vertical-align: top;">C * 20</td>
800
801
802
803
804
805      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
806
807
808
809
810
811      <td style="vertical-align: top;"> 
812     
813     
814     
815     
816      <p style="font-style: normal;">Top boundary condition of the
817perturbation pressure.&nbsp; </p>
818
819
820
821
822 
823     
824     
825     
826     
827      <p style="font-style: normal;">Allowed values are <span style="font-style: italic;">'dirichlet'</span>
828(p(k=nz+1)= 0.0) or <span style="font-style: italic;">'neumann'</span>
829(p(k=nz+1)=p(k=nz)).&nbsp; </p>
830
831
832
833
834 
835     
836     
837     
838     
839      <p>Simultaneous use
840of Neumann boundary conditions both at the
841top and bottom boundary (<a href="#bc_p_b">bc_p_b</a>)
842usually yields no consistent solution for the perturbation pressure and
843should be avoided. Since at the bottom boundary the Neumann
844condition&nbsp; is a good choice (see <a href="#bc_p_b">bc_p_b</a>),
845a Dirichlet condition should be set at the top boundary.</p>
846
847
848
849
850 </td>
851
852
853
854
855
856    </tr>
857
858
859
860
861 <tr>
862
863
864
865
866 <td style="vertical-align: top;">
867     
868     
869     
870     
871      <p><a name="bc_pt_b"></a><b>bc_pt_b</b></p>
872
873
874
875
876
877      </td>
878
879
880
881
882 <td style="vertical-align: top;">C*20</td>
883
884
885
886
887
888      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
889
890
891
892
893
894      <td style="vertical-align: top;"> 
895     
896     
897     
898     
899      <p style="font-style: normal;">Bottom boundary condition of the
900potential temperature.&nbsp; </p>
901
902
903
904
905 
906     
907     
908     
909     
910      <p>Allowed values
911are <span style="font-style: italic;">'dirichlet'</span>
912(pt(k=0) = const. = <a href="#pt_surface">pt_surface</a>
913+ <a href="#pt_surface_initial_change">pt_surface_initial_change</a>;
914the user may change this value during the run using user-defined code)
915and <span style="font-style: italic;">'neumann'</span>
916(pt(k=0)=pt(k=1)).&nbsp; <br>
917
918
919
920
921
922When a constant surface sensible heat flux is used (<a href="#surface_heatflux">surface_heatflux</a>), <b>bc_pt_b</b>
923= <span style="font-style: italic;">'neumann'</span>
924must be used, because otherwise the resolved scale may contribute to
925the surface flux so that a constant value cannot be guaranteed.</p>
926
927
928
929
930     
931     
932     
933     
934      <p>In the <a href="chapter_3.8.html">coupled</a> atmosphere executable,&nbsp;<a href="chapter_4.2.html#bc_pt_b">bc_pt_b</a> is internally set and does not need to be prescribed.</p>
935
936
937
938
939
940      </td>
941
942
943
944
945 </tr>
946
947
948
949
950 <tr>
951
952
953
954
955 <td style="vertical-align: top;"> 
956     
957     
958     
959     
960      <p><a name="pc_pt_t"></a><b>bc_pt_t</b></p>
961
962
963
964
965
966      </td>
967
968
969
970
971 <td style="vertical-align: top;">C * 20</td>
972
973
974
975
976
977      <td style="vertical-align: top;"><span style="font-style: italic;">'initial_ gradient'</span></td>
978
979
980
981
982
983      <td style="vertical-align: top;"> 
984     
985     
986     
987     
988      <p style="font-style: normal;">Top boundary condition of the
989potential temperature.&nbsp; </p>
990
991
992
993
994 
995     
996     
997     
998     
999      <p>Allowed are the
1000values <span style="font-style: italic;">'dirichlet' </span>(pt(k=nz+1)
1001does not change during the run), <span style="font-style: italic;">'neumann'</span>
1002(pt(k=nz+1)=pt(k=nz)), and <span style="font-style: italic;">'initial_gradient'</span>.
1003With the 'initial_gradient'-condition the value of the temperature
1004gradient at the top is
1005calculated from the initial
1006temperature profile (see <a href="#pt_surface">pt_surface</a>,
1007      <a href="#pt_vertical_gradient">pt_vertical_gradient</a>)
1008by bc_pt_t_val = (pt_init(k=nz+1) -
1009pt_init(k=nz)) / dzu(nz+1).<br>
1010
1011
1012
1013
1014
1015Using this value (assumed constant during the
1016run) the temperature boundary values are calculated as&nbsp; </p>
1017
1018
1019
1020
1021
1022     
1023     
1024     
1025     
1026      <ul>
1027
1028
1029
1030
1031 
1032       
1033       
1034       
1035       
1036        <p style="font-style: normal;">pt(k=nz+1) =
1037pt(k=nz) +
1038bc_pt_t_val * dzu(nz+1)</p>
1039
1040
1041
1042
1043 
1044     
1045     
1046     
1047     
1048      </ul>
1049
1050
1051
1052
1053 
1054     
1055     
1056     
1057     
1058      <p style="font-style: normal;">(up to k=nz the prognostic
1059equation for the temperature is solved).<br>
1060
1061
1062
1063
1064
1065When a constant sensible heat flux is used at the top boundary (<a href="chapter_4.1.html#top_heatflux">top_heatflux</a>),
1066      <b>bc_pt_t</b> = <span style="font-style: italic;">'neumann'</span>
1067must be used, because otherwise the resolved scale may contribute to
1068the top flux so that a constant value cannot be guaranteed.</p>
1069
1070
1071
1072
1073 </td>
1074
1075
1076
1077
1078
1079    </tr>
1080
1081
1082
1083
1084 <tr>
1085
1086
1087
1088
1089 <td style="vertical-align: top;">
1090     
1091     
1092     
1093     
1094      <p><a name="bc_q_b"></a><b>bc_q_b</b></p>
1095
1096
1097
1098
1099
1100      </td>
1101
1102
1103
1104
1105 <td style="vertical-align: top;">C * 20</td>
1106
1107
1108
1109
1110
1111      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1112
1113
1114
1115
1116
1117      <td style="vertical-align: top;"> 
1118     
1119     
1120     
1121     
1122      <p style="font-style: normal;">Bottom boundary condition of the
1123specific humidity / total water content.&nbsp; </p>
1124
1125
1126
1127
1128 
1129     
1130     
1131     
1132     
1133      <p>Allowed
1134values are <span style="font-style: italic;">'dirichlet'</span>
1135(q(k=0) = const. = <a href="#q_surface">q_surface</a>
1136+ <a href="#q_surface_initial_change">q_surface_initial_change</a>;
1137the user may change this value during the run using user-defined code)
1138and <span style="font-style: italic;">'neumann'</span>
1139(q(k=0)=q(k=1)).&nbsp; <br>
1140
1141
1142
1143
1144
1145When a constant surface latent heat flux is used (<a href="#surface_waterflux">surface_waterflux</a>), <b>bc_q_b</b>
1146= <span style="font-style: italic;">'neumann'</span>
1147must be used, because otherwise the resolved scale may contribute to
1148the surface flux so that a constant value cannot be guaranteed.</p>
1149
1150
1151
1152
1153
1154      </td>
1155
1156
1157
1158
1159 </tr>
1160
1161
1162
1163
1164 <tr>
1165
1166
1167
1168
1169 <td style="vertical-align: top;"> 
1170     
1171     
1172     
1173     
1174      <p><a name="bc_q_t"></a><b>bc_q_t</b></p>
1175
1176
1177
1178
1179
1180      </td>
1181
1182
1183
1184
1185 <td style="vertical-align: top;"><span style="font-style: italic;">C
1186* 20</span></td>
1187
1188
1189
1190
1191 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1192
1193
1194
1195
1196
1197      <td style="vertical-align: top;"> 
1198     
1199     
1200     
1201     
1202      <p style="font-style: normal;">Top boundary condition of the
1203specific humidity / total water content.&nbsp; </p>
1204
1205
1206
1207
1208 
1209     
1210     
1211     
1212     
1213      <p>Allowed
1214are the values <span style="font-style: italic;">'dirichlet'</span>
1215(q(k=nz) and q(k=nz+1) do
1216not change during the run) and <span style="font-style: italic;">'neumann'</span>.
1217With the Neumann boundary
1218condition the value of the humidity gradient at the top is calculated
1219from the
1220initial humidity profile (see <a href="#q_surface">q_surface</a>,
1221      <a href="#q_vertical_gradient">q_vertical_gradient</a>)
1222by: bc_q_t_val = ( q_init(k=nz) - q_init(k=nz-1)) / dzu(nz).<br>
1223
1224
1225
1226
1227
1228Using this value (assumed constant during the run) the humidity
1229boundary values
1230are calculated as&nbsp; </p>
1231
1232
1233
1234
1235 
1236     
1237     
1238     
1239     
1240      <ul>
1241
1242
1243
1244
1245 
1246       
1247       
1248       
1249       
1250        <p style="font-style: normal;">q(k=nz+1) =q(k=nz) +
1251bc_q_t_val * dzu(nz+1)</p>
1252
1253
1254
1255
1256 
1257     
1258     
1259     
1260     
1261      </ul>
1262
1263
1264
1265
1266 
1267     
1268     
1269     
1270     
1271      <p style="font-style: normal;">(up tp k=nz the prognostic
1272equation for q is solved). </p>
1273
1274
1275
1276
1277 </td>
1278
1279
1280
1281
1282 </tr>
1283
1284
1285
1286
1287 <tr>
1288
1289
1290
1291
1292
1293      <td style="vertical-align: top;"> 
1294     
1295     
1296     
1297     
1298      <p><a name="bc_s_b"></a><b>bc_s_b</b></p>
1299
1300
1301
1302
1303 </td>
1304
1305
1306
1307
1308
1309      <td style="vertical-align: top;">C * 20</td>
1310
1311
1312
1313
1314 <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1315
1316
1317
1318
1319
1320      <td style="vertical-align: top;"> 
1321     
1322     
1323     
1324     
1325      <p style="font-style: normal;">Bottom boundary condition of the
1326scalar concentration.&nbsp; </p>
1327
1328
1329
1330
1331 
1332     
1333     
1334     
1335     
1336      <p>Allowed values
1337are <span style="font-style: italic;">'dirichlet'</span>
1338(s(k=0) = const. = <a href="#s_surface">s_surface</a>
1339+ <a href="#s_surface_initial_change">s_surface_initial_change</a>;
1340the user may change this value during the run using user-defined code)
1341and <span style="font-style: italic;">'neumann'</span>
1342(s(k=0) =
1343s(k=1)).&nbsp; <br>
1344
1345
1346
1347
1348
1349When a constant surface concentration flux is used (<a href="#surface_scalarflux">surface_scalarflux</a>), <b>bc_s_b</b>
1350= <span style="font-style: italic;">'neumann'</span>
1351must be used, because otherwise the resolved scale may contribute to
1352the surface flux so that a constant value cannot be guaranteed.</p>
1353
1354
1355
1356
1357
1358      </td>
1359
1360
1361
1362
1363 </tr>
1364
1365
1366
1367
1368 <tr>
1369
1370
1371
1372
1373 <td style="vertical-align: top;"> 
1374     
1375     
1376     
1377     
1378      <p><a name="bc_s_t"></a><b>bc_s_t</b></p>
1379
1380
1381
1382
1383
1384      </td>
1385
1386
1387
1388
1389 <td style="vertical-align: top;">C * 20</td>
1390
1391
1392
1393
1394
1395      <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1396
1397
1398
1399
1400
1401      <td style="vertical-align: top;"> 
1402     
1403     
1404     
1405     
1406      <p style="font-style: normal;">Top boundary condition of the
1407scalar concentration.&nbsp; </p>
1408
1409
1410
1411
1412 
1413     
1414     
1415     
1416     
1417      <p>Allowed are the
1418values <span style="font-style: italic;">'dirichlet'</span>
1419(s(k=nz) and s(k=nz+1) do
1420not change during the run) and <span style="font-style: italic;">'neumann'</span>.
1421With the Neumann boundary
1422condition the value of the scalar concentration gradient at the top is
1423calculated
1424from the initial scalar concentration profile (see <a href="#s_surface">s_surface</a>, <a href="#s_vertical_gradient">s_vertical_gradient</a>)
1425by: bc_s_t_val = (s_init(k=nz) - s_init(k=nz-1)) / dzu(nz).<br>
1426
1427
1428
1429
1430
1431Using this value (assumed constant during the run) the concentration
1432boundary values
1433are calculated as </p>
1434
1435
1436
1437
1438 
1439     
1440     
1441     
1442     
1443      <ul>
1444
1445
1446
1447
1448 
1449       
1450       
1451       
1452       
1453        <p style="font-style: normal;">s(k=nz+1) = s(k=nz) +
1454bc_s_t_val * dzu(nz+1)</p>
1455
1456
1457
1458
1459 
1460     
1461     
1462     
1463     
1464      </ul>
1465
1466
1467
1468
1469 
1470     
1471     
1472     
1473     
1474      <p style="font-style: normal;">(up to k=nz the prognostic
1475equation for the scalar concentration is
1476solved).</p>
1477
1478
1479
1480
1481 </td>
1482
1483
1484
1485
1486 </tr>
1487
1488
1489
1490
1491 <tr>
1492
1493
1494
1495
1496      <td style="vertical-align: top;"><a name="bc_sa_t"></a><span style="font-weight: bold;">bc_sa_t</span></td>
1497
1498
1499
1500
1501      <td style="vertical-align: top;">C * 20</td>
1502
1503
1504
1505
1506      <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1507
1508
1509
1510
1511      <td style="vertical-align: top;">
1512     
1513     
1514     
1515     
1516      <p style="font-style: normal;">Top boundary condition of the salinity.&nbsp; </p>
1517
1518
1519
1520
1521 
1522     
1523     
1524     
1525     
1526      <p>This parameter only comes into effect for ocean runs (see parameter <a href="#ocean">ocean</a>).</p>
1527
1528
1529
1530
1531     
1532     
1533     
1534     
1535      <p style="font-style: normal;">Allowed are the
1536values <span style="font-style: italic;">'dirichlet' </span>(sa(k=nz+1)
1537does not change during the run) and <span style="font-style: italic;">'neumann'</span>
1538(sa(k=nz+1)=sa(k=nz))<span style="font-style: italic;"></span>.&nbsp;<br>
1539
1540
1541
1542
1543      <br>
1544
1545
1546
1547
1548
1549When a constant salinity flux is used at the top boundary (<a href="chapter_4.1.html#top_salinityflux">top_salinityflux</a>),
1550      <b>bc_sa_t</b> = <span style="font-style: italic;">'neumann'</span>
1551must be used, because otherwise the resolved scale may contribute to
1552the top flux so that a constant value cannot be guaranteed.</p>
1553
1554
1555
1556
1557      </td>
1558
1559
1560
1561
1562    </tr>
1563
1564
1565
1566
1567    <tr>
1568
1569
1570
1571
1572 <td style="vertical-align: top;"> 
1573     
1574     
1575     
1576     
1577      <p><a name="bc_uv_b"></a><b>bc_uv_b</b></p>
1578
1579
1580
1581
1582
1583      </td>
1584
1585
1586
1587
1588 <td style="vertical-align: top;">C * 20</td>
1589
1590
1591
1592
1593
1594      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1595
1596
1597
1598
1599
1600      <td style="vertical-align: top;"> 
1601     
1602     
1603     
1604     
1605      <p style="font-style: normal;">Bottom boundary condition of the
1606horizontal velocity components u and v.&nbsp; </p>
1607
1608
1609
1610
1611 
1612     
1613     
1614     
1615     
1616      <p>Allowed
1617values are <span style="font-style: italic;">'dirichlet' </span>and
1618      <span style="font-style: italic;">'neumann'</span>. <b>bc_uv_b</b>
1619= <span style="font-style: italic;">'dirichlet'</span>
1620yields the
1621no-slip condition with u=v=0 at the bottom. Due to the staggered grid
1622u(k=0) and v(k=0) are located at z = - 0,5 * <a href="#dz">dz</a>
1623(below the bottom), while u(k=1) and v(k=1) are located at z = +0,5 *
1624dz. u=v=0 at the bottom is guaranteed using mirror boundary
1625condition:&nbsp; </p>
1626
1627
1628
1629
1630 
1631     
1632     
1633     
1634     
1635      <ul>
1636
1637
1638
1639
1640 
1641       
1642       
1643       
1644       
1645        <p style="font-style: normal;">u(k=0) = - u(k=1) and v(k=0) = -
1646v(k=1)</p>
1647
1648
1649
1650
1651 
1652     
1653     
1654     
1655     
1656      </ul>
1657
1658
1659
1660
1661 
1662     
1663     
1664     
1665     
1666      <p style="font-style: normal;">The
1667Neumann boundary condition
1668yields the free-slip condition with u(k=0) = u(k=1) and v(k=0) =
1669v(k=1).
1670With Prandtl - layer switched on, the free-slip condition is not
1671allowed (otherwise the run will be terminated)<font color="#000000">.</font></p>
1672
1673
1674
1675
1676
1677      </td>
1678
1679
1680
1681
1682 </tr>
1683
1684
1685
1686
1687 <tr>
1688
1689
1690
1691
1692 <td style="vertical-align: top;"> 
1693     
1694     
1695     
1696     
1697      <p><a name="bc_uv_t"></a><b>bc_uv_t</b></p>
1698
1699
1700
1701
1702
1703      </td>
1704
1705
1706
1707
1708 <td style="vertical-align: top;">C * 20</td>
1709
1710
1711
1712
1713
1714      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1715
1716
1717
1718
1719
1720      <td style="vertical-align: top;"> 
1721     
1722     
1723     
1724     
1725      <p style="font-style: normal;">Top boundary condition of the
1726horizontal velocity components u and v.&nbsp; </p>
1727
1728
1729
1730
1731 
1732     
1733     
1734     
1735     
1736      <p>Allowed
1737values are <span style="font-style: italic;">'dirichlet'</span>, <span style="font-style: italic;">'dirichlet_0'</span>
1738and <span style="font-style: italic;">'neumann'</span>.
1739The
1740Dirichlet condition yields u(k=nz+1) = ug(nz+1) and v(k=nz+1) =
1741vg(nz+1),
1742Neumann condition yields the free-slip condition with u(k=nz+1) =
1743u(k=nz) and v(k=nz+1) = v(k=nz) (up to k=nz the prognostic equations
1744for the velocities are solved). The special condition&nbsp;<span style="font-style: italic;">'dirichlet_0'</span> can be used for channel flow, it yields the no-slip condition u(k=nz+1) = ug(nz+1) = 0 and v(k=nz+1) =
1745vg(nz+1) = 0.</p>
1746
1747
1748
1749
1750     
1751     
1752     
1753     
1754      <p>In the <a href="chapter_3.8.html">coupled</a> ocean executable, <a href="chapter_4.2.html#bc_uv_t">bc_uv_t</a>&nbsp;is internally set ('neumann') and does not need to be prescribed.</p>
1755
1756
1757
1758
1759 </td>
1760
1761
1762
1763
1764 </tr>
1765
1766
1767
1768
1769 <tr>
1770
1771
1772
1773
1774      <td style="vertical-align: top;"><a name="bottom_salinityflux"></a><span style="font-weight: bold;">bottom_salinityflux</span></td>
1775
1776
1777
1778
1779      <td style="vertical-align: top;">R</td>
1780
1781
1782
1783
1784      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
1785
1786
1787
1788
1789      <td style="vertical-align: top;">
1790     
1791     
1792     
1793     
1794      <p>Kinematic salinity flux near the surface (in psu m/s).&nbsp;</p>
1795
1796
1797
1798
1799This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).
1800     
1801     
1802     
1803     
1804      <p>The
1805respective salinity flux value is used
1806as bottom (horizontally homogeneous) boundary condition for the salinity equation. This additionally requires that a Neumann
1807condition must be used for the salinity, which is currently the only available condition.<br>
1808
1809
1810
1811
1812 </p>
1813
1814
1815
1816
1817 </td>
1818
1819
1820
1821
1822    </tr>
1823
1824
1825
1826
1827    <tr>
1828
1829
1830
1831
1832
1833      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_height"></a>building_height</span></td>
1834
1835
1836
1837
1838
1839      <td style="vertical-align: top;">R</td>
1840
1841
1842
1843
1844 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1845
1846
1847
1848
1849 <td>Height
1850of a single building in m.<br>
1851
1852
1853
1854
1855 <br>
1856
1857
1858
1859
1860 <span style="font-weight: bold;">building_height</span> must
1861be less than the height of the model domain. This parameter requires
1862the use of&nbsp;<a href="#topography">topography</a>
1863= <span style="font-style: italic;">'single_building'</span>.</td>
1864
1865
1866
1867
1868
1869    </tr>
1870
1871
1872
1873
1874 <tr>
1875
1876
1877
1878
1879 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_length_x"></a>building_length_x</span></td>
1880
1881
1882
1883
1884
1885      <td style="vertical-align: top;">R</td>
1886
1887
1888
1889
1890 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1891
1892
1893
1894
1895 <td><span style="font-style: italic;"></span>Width of a single
1896building in m.<br>
1897
1898
1899
1900
1901 <br>
1902
1903
1904
1905
1906
1907Currently, <span style="font-weight: bold;">building_length_x</span>
1908must be at least <span style="font-style: italic;">3
1909*&nbsp;</span><a style="font-style: italic;" href="#dx">dx</a> and no more than <span style="font-style: italic;">(&nbsp;</span><a style="font-style: italic;" href="#nx">nx</a><span style="font-style: italic;"> - 1 ) </span><span style="font-style: italic;"> * <a href="#dx">dx</a>
1910      </span><span style="font-style: italic;">- <a href="#building_wall_left">building_wall_left</a></span>.
1911This parameter requires the use of&nbsp;<a href="#topography">topography</a>
1912= <span style="font-style: italic;">'single_building'</span>.</td>
1913
1914
1915
1916
1917
1918    </tr>
1919
1920
1921
1922
1923 <tr>
1924
1925
1926
1927
1928 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_length_y"></a>building_length_y</span></td>
1929
1930
1931
1932
1933
1934      <td style="vertical-align: top;">R</td>
1935
1936
1937
1938
1939 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1940
1941
1942
1943
1944 <td>Depth
1945of a single building in m.<br>
1946
1947
1948
1949
1950 <br>
1951
1952
1953
1954
1955
1956Currently, <span style="font-weight: bold;">building_length_y</span>
1957must be at least <span style="font-style: italic;">3
1958*&nbsp;</span><a style="font-style: italic;" href="#dy">dy</a> and no more than <span style="font-style: italic;">(&nbsp;</span><a style="font-style: italic;" href="#ny">ny</a><span style="font-style: italic;"> - 1 )&nbsp;</span><span style="font-style: italic;"> * <a href="#dy">dy</a></span><span style="font-style: italic;"> - <a href="#building_wall_south">building_wall_south</a></span>. This parameter requires
1959the use of&nbsp;<a href="#topography">topography</a>
1960= <span style="font-style: italic;">'single_building'</span>.</td>
1961
1962
1963
1964
1965
1966    </tr>
1967
1968
1969
1970
1971 <tr>
1972
1973
1974
1975
1976 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_wall_left"></a>building_wall_left</span></td>
1977
1978
1979
1980
1981
1982      <td style="vertical-align: top;">R</td>
1983
1984
1985
1986
1987 <td style="vertical-align: top;"><span style="font-style: italic;">building centered in x-direction</span></td>
1988
1989
1990
1991
1992
1993      <td>x-coordinate of the left building wall (distance between the
1994left building wall and the left border of the model domain) in m.<br>
1995
1996
1997
1998
1999
2000      <br>
2001
2002
2003
2004
2005
2006Currently, <span style="font-weight: bold;">building_wall_left</span>
2007must be at least <span style="font-style: italic;">1
2008*&nbsp;</span><a style="font-style: italic;" href="#dx">dx</a> and less than <span style="font-style: italic;">( <a href="#nx">nx</a>&nbsp;
2009- 1 ) * <a href="#dx">dx</a> -&nbsp; <a href="#building_length_x">building_length_x</a></span>.
2010This parameter requires the use of&nbsp;<a href="#topography">topography</a>
2011= <span style="font-style: italic;">'single_building'</span>.<br>
2012
2013
2014
2015
2016
2017      <br>
2018
2019
2020
2021
2022
2023The default value&nbsp;<span style="font-weight: bold;">building_wall_left</span>
2024= <span style="font-style: italic;">( ( <a href="#nx">nx</a>&nbsp;+
20251 ) * <a href="#dx">dx</a> -&nbsp; <a href="#building_length_x">building_length_x</a> ) / 2</span>
2026centers the building in x-direction.&nbsp;<font color="#000000">Due to the staggered grid the building will be displaced by -0.5 <a href="chapter_4.1.html#dx">dx</a> in x-direction and -0.5 <a href="chapter_4.1.html#dy">dy</a> in y-direction.</font> </td>
2027
2028
2029
2030
2031 </tr>
2032
2033
2034
2035
2036 <tr>
2037
2038
2039
2040
2041
2042      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_wall_south"></a>building_wall_south</span></td>
2043
2044
2045
2046
2047
2048      <td style="vertical-align: top;">R</td>
2049
2050
2051
2052
2053 <td style="vertical-align: top;"><span style="font-style: italic;"></span><span style="font-style: italic;">building centered in y-direction</span></td>
2054
2055
2056
2057
2058
2059      <td>y-coordinate of the South building wall (distance between the
2060South building wall and the South border of the model domain) in m.<br>
2061
2062
2063
2064
2065
2066      <br>
2067
2068
2069
2070
2071
2072Currently, <span style="font-weight: bold;">building_wall_south</span>
2073must be at least <span style="font-style: italic;">1
2074*&nbsp;</span><a style="font-style: italic;" href="#dy">dy</a> and less than <span style="font-style: italic;">( <a href="#ny">ny</a>&nbsp;
2075- 1 ) * <a href="#dy">dy</a> -&nbsp; <a href="#building_length_y">building_length_y</a></span>.
2076This parameter requires the use of&nbsp;<a href="#topography">topography</a>
2077= <span style="font-style: italic;">'single_building'</span>.<br>
2078
2079
2080
2081
2082
2083      <br>
2084
2085
2086
2087
2088
2089The default value&nbsp;<span style="font-weight: bold;">building_wall_south</span>
2090= <span style="font-style: italic;">( ( <a href="#ny">ny</a>&nbsp;+
20911 ) * <a href="#dy">dy</a> -&nbsp; <a href="#building_length_y">building_length_y</a> ) / 2</span>
2092centers the building in y-direction.&nbsp;<font color="#000000">Due to the staggered grid the building will be displaced by -0.5 <a href="chapter_4.1.html#dx">dx</a> in x-direction and -0.5 <a href="chapter_4.1.html#dy">dy</a> in y-direction.</font> </td>
2093
2094
2095
2096
2097 </tr>
2098
2099
2100
2101
2102 <tr><td><a name="canopy_mode"></a><span style="font-weight: bold;">canopy_mode</span></td><td>C * 20</td><td><span style="font-style: italic;">'block'</span></td><td>Canopy mode.<br><br><font color="#000000">
2103Besides using the default value, that will create a horizontally
2104homogeneous plant canopy that extends over the total horizontal
2105extension of the model domain, the user may add code to the user
2106interface subroutine <a href="chapter_3.5.1.html#user_init_plant_canopy">user_init_plant_canopy</a>
2107to allow further canopy&nbsp;modes. <br><br>The setting of <a href="#canopy_mode">canopy_mode</a> becomes only active, if&nbsp;<a href="#plant_canopy">plant_canopy</a> has been set <span style="font-style: italic;">.T.</span> and a non-zero <a href="#drag_coefficient">drag_coefficient</a> has been defined.</font></td></tr><tr>
2108
2109
2110
2111
2112
2113      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="cloud_droplets"></a>cloud_droplets</span><br>
2114
2115
2116
2117
2118
2119      </td>
2120
2121
2122
2123
2124 <td style="vertical-align: top;">L<br>
2125
2126
2127
2128
2129 </td>
2130
2131
2132
2133
2134
2135      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span><br>
2136
2137
2138
2139
2140 </td>
2141
2142
2143
2144
2145
2146      <td style="vertical-align: top;">Parameter to switch on
2147usage of cloud droplets.<br>
2148
2149
2150
2151
2152 <br>
2153
2154
2155
2156
2157
2158<span style="font-weight: bold;"></span><span style="font-family: monospace;"></span>
2159
2160
2161
2162
2163Cloud droplets require to use&nbsp;particles (i.e. the NAMELIST group <span style="font-family: Courier New,Courier,monospace;">particles_par</span> has to be included in the parameter file<span style="font-family: monospace;"></span>). Then each particle is a representative for a certain number of droplets. The droplet
2164features (number of droplets, initial radius, etc.) can be steered with
2165the&nbsp; respective particle parameters (see e.g. <a href="#chapter_4.2.html#radius">radius</a>).
2166The real number of initial droplets in a grid cell is equal to the
2167initial number of droplets (defined by the particle source parameters <span lang="en-GB"><font face="Thorndale, serif"> </font></span><a href="chapter_4.2.html#pst"><span lang="en-GB"><font face="Thorndale, serif">pst</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#psl"><span lang="en-GB"><font face="Thorndale, serif">psl</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#psr"><span lang="en-GB"><font face="Thorndale, serif">psr</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#pss"><span lang="en-GB"><font face="Thorndale, serif">pss</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#psn"><span lang="en-GB"><font face="Thorndale, serif">psn</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#psb"><span lang="en-GB"><font face="Thorndale, serif">psb</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#pdx"><span lang="en-GB"><font face="Thorndale, serif">pdx</font></span></a><span lang="en-GB"><font face="Thorndale, serif">, </font></span><a href="chapter_4.2.html#pdy"><span lang="en-GB"><font face="Thorndale, serif">pdy</font></span></a>
2168      <span lang="en-GB"><font face="Thorndale, serif">and
2169      </font></span><a href="chapter_4.2.html#pdz"><span lang="en-GB"><font face="Thorndale, serif">pdz</font></span></a><span lang="en-GB"></span><span lang="en-GB"></span>)
2170times the <a href="#initial_weighting_factor">initial_weighting_factor</a>.<br>
2171
2172
2173
2174
2175
2176      <br>
2177
2178
2179
2180
2181
2182In case of using cloud droplets, the default condensation scheme in
2183PALM cannot be used, i.e. <a href="#cloud_physics">cloud_physics</a>
2184must be set <span style="font-style: italic;">.F.</span>.<br>
2185
2186
2187
2188
2189
2190      </td>
2191
2192
2193
2194
2195 </tr>
2196
2197
2198
2199
2200 <tr>
2201
2202
2203
2204
2205 <td style="vertical-align: top;"> 
2206     
2207     
2208     
2209     
2210      <p><a name="cloud_physics"></a><b>cloud_physics</b></p>
2211
2212
2213
2214
2215
2216      </td>
2217
2218
2219
2220
2221 <td style="vertical-align: top;">L<br>
2222
2223
2224
2225
2226 </td>
2227
2228
2229
2230
2231
2232      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
2233
2234
2235
2236
2237 <td style="vertical-align: top;"> 
2238     
2239     
2240     
2241     
2242      <p>Parameter to switch
2243on the condensation scheme.&nbsp; </p>
2244
2245
2246
2247
2248
2249For <b>cloud_physics =</b> <span style="font-style: italic;">.TRUE.</span>, equations
2250for the
2251liquid water&nbsp;
2252content and the liquid water potential temperature are solved instead
2253of those for specific humidity and potential temperature. Note
2254that a grid volume is assumed to be either completely saturated or
2255completely
2256unsaturated (0%-or-100%-scheme). A simple precipitation scheme can
2257additionally be switched on with parameter <a href="#precipitation">precipitation</a>.
2258Also cloud-top cooling by longwave radiation can be utilized (see <a href="#radiation">radiation</a>)<br>
2259
2260
2261
2262
2263 <b><br>
2264
2265
2266
2267
2268
2269cloud_physics =</b> <span style="font-style: italic;">.TRUE.
2270      </span>requires&nbsp;<a href="#humidity">humidity</a>
2271=<span style="font-style: italic;"> .TRUE.</span> .<br>
2272
2273
2274
2275
2276
2277Detailed information about the condensation scheme is given in the
2278description of the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM-1/Dokumentationen/Cloud_physics/wolken.pdf">cloud
2279physics module</a> (pdf-file, only in German).<br>
2280
2281
2282
2283
2284 <br>
2285
2286
2287
2288
2289
2290This condensation scheme is not allowed if cloud droplets are simulated
2291explicitly (see <a href="#cloud_droplets">cloud_droplets</a>).<br>
2292
2293
2294
2295
2296
2297      </td>
2298
2299
2300
2301
2302 </tr>
2303
2304
2305
2306
2307 <tr>
2308
2309
2310
2311
2312 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="conserve_volume_flow"></a>conserve_volume_flow</span></td>
2313
2314
2315
2316
2317
2318      <td style="vertical-align: top;">L</td>
2319
2320
2321
2322
2323 <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
2324
2325
2326
2327
2328 <td>Conservation
2329of volume flow in x- and y-direction.<br>
2330
2331
2332
2333
2334 <br>
2335
2336
2337
2338
2339 <span style="font-weight: bold;">conserve_volume_flow</span>
2340= <span style="font-style: italic;">.TRUE.</span>
2341guarantees that the volume flow through the xz- or yz-cross-section of
2342the total model domain remains constant (equal to the initial value at
2343t=0) throughout the run.<br>
2344
2345
2346
2347
2348
2349      </td>
2350
2351
2352
2353
2354 </tr>
2355
2356
2357
2358
2359 <tr>
2360
2361
2362
2363
2364 <td style="vertical-align: top;"> 
2365     
2366     
2367     
2368     
2369      <p><a name="cut_spline_overshoot"></a><b>cut_spline_overshoot</b></p>
2370
2371
2372
2373
2374
2375      </td>
2376
2377
2378
2379
2380 <td style="vertical-align: top;">L</td>
2381
2382
2383
2384
2385
2386      <td style="vertical-align: top;"><span style="font-style: italic;">.T.</span></td>
2387
2388
2389
2390
2391 <td style="vertical-align: top;"> 
2392     
2393     
2394     
2395     
2396      <p>Cuts off of
2397so-called overshoots, which can occur with the
2398upstream-spline scheme.&nbsp; </p>
2399
2400
2401
2402
2403 
2404     
2405     
2406     
2407     
2408      <p><font color="#000000">The cubic splines tend to overshoot in
2409case of discontinuous changes of variables between neighbouring grid
2410points.</font><font color="#ff0000"> </font><font color="#000000">This
2411may lead to errors in calculating the advection tendency.</font>
2412Choice
2413of <b>cut_spline_overshoot</b> = <i>.TRUE.</i>
2414(switched on by
2415default)
2416allows variable values not to exceed an interval defined by the
2417respective adjacent grid points. This interval can be adjusted
2418seperately for every prognostic variable (see initialization parameters
2419      <a href="#overshoot_limit_e">overshoot_limit_e</a>, <a href="#overshoot_limit_pt">overshoot_limit_pt</a>, <a href="#overshoot_limit_u">overshoot_limit_u</a>,
2420etc.). This might be necessary in case that the
2421default interval has a non-tolerable effect on the model
2422results.&nbsp; </p>
2423
2424
2425
2426
2427 
2428     
2429     
2430     
2431     
2432      <p>Overshoots may also be removed
2433using the parameters <a href="#ups_limit_e">ups_limit_e</a>,
2434      <a href="#ups_limit_pt">ups_limit_pt</a>,
2435etc. as well as by applying a long-filter (see <a href="#long_filter_factor">long_filter_factor</a>).</p>
2436
2437
2438
2439
2440
2441      </td>
2442
2443
2444
2445
2446 </tr>
2447
2448
2449
2450
2451 <tr>
2452
2453
2454
2455
2456 <td style="vertical-align: top;"> 
2457     
2458     
2459     
2460     
2461      <p><a name="damp_level_1d"></a><b>damp_level_1d</b></p>
2462
2463
2464
2465
2466
2467      </td>
2468
2469
2470
2471
2472 <td style="vertical-align: top;">R</td>
2473
2474
2475
2476
2477
2478      <td style="vertical-align: top;"><span style="font-style: italic;">zu(nz+1)</span></td>
2479
2480
2481
2482
2483
2484      <td style="vertical-align: top;"> 
2485     
2486     
2487     
2488     
2489      <p>Height where
2490the damping layer begins in the 1d-model
2491(in m).&nbsp; </p>
2492
2493
2494
2495
2496 
2497     
2498     
2499     
2500     
2501      <p>This parameter is used to
2502switch on a damping layer for the
25031d-model, which is generally needed for the damping of inertia
2504oscillations. Damping is done by gradually increasing the value
2505of the eddy diffusivities about 10% per vertical grid level
2506(starting with the value at the height given by <b>damp_level_1d</b>,
2507or possibly from the next grid pint above), i.e. K<sub>m</sub>(k+1)
2508=
25091.1 * K<sub>m</sub>(k).
2510The values of K<sub>m</sub> are limited to 10 m**2/s at
2511maximum.&nbsp; <br>
2512
2513
2514
2515
2516
2517This parameter only comes into effect if the 1d-model is switched on
2518for
2519the initialization of the 3d-model using <a href="#initializing_actions">initializing_actions</a>
2520= <span style="font-style: italic;">'set_1d-model_profiles'</span>.
2521      <br>
2522
2523
2524
2525
2526 </p>
2527
2528
2529
2530
2531 </td>
2532
2533
2534
2535
2536 </tr>
2537
2538
2539
2540
2541 <tr>
2542
2543
2544
2545
2546 <td style="vertical-align: top;"><a name="dissipation_1d"></a><span style="font-weight: bold;">dissipation_1d</span><br>
2547
2548
2549
2550
2551
2552      </td>
2553
2554
2555
2556
2557 <td style="vertical-align: top;">C*20<br>
2558
2559
2560
2561
2562
2563      </td>
2564
2565
2566
2567
2568 <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
2569
2570
2571
2572
2573 <span style="font-style: italic;">model'</span><br>
2574
2575
2576
2577
2578 </td>
2579
2580
2581
2582
2583
2584      <td style="vertical-align: top;">Calculation method for
2585the energy dissipation term in the TKE equation of the 1d-model.<br>
2586
2587
2588
2589
2590
2591      <br>
2592
2593
2594
2595
2596
2597By default the dissipation is calculated as in the 3d-model using diss
2598= (0.19 + 0.74 * l / l_grid) * e**1.5 / l.<br>
2599
2600
2601
2602
2603 <br>
2604
2605
2606
2607
2608
2609Setting <span style="font-weight: bold;">dissipation_1d</span>
2610= <span style="font-style: italic;">'detering'</span>
2611forces the dissipation to be calculated as diss = 0.064 * e**1.5 / l.<br>
2612
2613
2614
2615
2616
2617      </td>
2618
2619
2620
2621
2622 </tr>
2623
2624
2625
2626
2627
2628    <tr><td><a name="drag_coefficient"></a><span style="font-weight: bold;">drag_coefficient</span></td><td>R</td><td><span style="font-style: italic;">0.0</span></td><td>Drag coefficient used in the plant canopy model.<br><br>This parameter has to be non-zero, if the parameter <a href="#plant_canopy">plant_canopy</a> is set <span style="font-style: italic;">.T.</span>.</td></tr><tr>
2629
2630
2631
2632
2633 <td style="vertical-align: top;"> 
2634     
2635     
2636     
2637     
2638      <p><a name="dt"></a><b>dt</b></p>
2639
2640
2641
2642
2643 </td>
2644
2645
2646
2647
2648
2649      <td style="vertical-align: top;">R</td>
2650
2651
2652
2653
2654 <td style="vertical-align: top;"><span style="font-style: italic;">variable</span></td>
2655
2656
2657
2658
2659
2660      <td style="vertical-align: top;"> 
2661     
2662     
2663     
2664     
2665      <p>Time step for
2666the 3d-model (in s).&nbsp; </p>
2667
2668
2669
2670
2671 
2672     
2673     
2674     
2675     
2676      <p>By default, (i.e.
2677if a Runge-Kutta scheme is used, see <a href="#timestep_scheme">timestep_scheme</a>)
2678the value of the time step is calculating after each time step
2679(following the time step criteria) and
2680used for the next step.</p>
2681
2682
2683
2684
2685 
2686     
2687     
2688     
2689     
2690      <p>If the user assigns <b>dt</b>
2691a value, then the time step is
2692fixed to this value throughout the whole run (whether it fulfills the
2693time step
2694criteria or not). However, changes are allowed for restart runs,
2695because <b>dt</b> can also be used as a <a href="chapter_4.2.html#dt_laufparameter">run
2696parameter</a>.&nbsp; </p>
2697
2698
2699
2700
2701 
2702     
2703     
2704     
2705     
2706      <p>In case that the
2707calculated time step meets the condition<br>
2708
2709
2710
2711
2712 </p>
2713
2714
2715
2716
2717 
2718     
2719     
2720     
2721     
2722      <ul>
2723
2724
2725
2726
2727
2728       
2729       
2730       
2731       
2732        <p><b>dt</b> &lt; 0.00001 * <a href="chapter_4.2.html#dt_max">dt_max</a> (with dt_max
2733= 20.0)</p>
2734
2735
2736
2737
2738 
2739     
2740     
2741     
2742     
2743      </ul>
2744
2745
2746
2747
2748 
2749     
2750     
2751     
2752     
2753      <p>the simulation will be
2754aborted. Such situations usually arise
2755in case of any numerical problem / instability which causes a
2756non-realistic increase of the wind speed.&nbsp; </p>
2757
2758
2759
2760
2761 
2762     
2763     
2764     
2765     
2766      <p>A
2767small time step due to a large mean horizontal windspeed
2768speed may be enlarged by using a coordinate transformation (see <a href="#galilei_transformation">galilei_transformation</a>),
2769in order to spare CPU time.<br>
2770
2771
2772
2773
2774 </p>
2775
2776
2777
2778
2779 
2780     
2781     
2782     
2783     
2784      <p>If the
2785leapfrog timestep scheme is used (see <a href="#timestep_scheme">timestep_scheme</a>)
2786a temporary time step value dt_new is calculated first, with dt_new = <a href="chapter_4.2.html#fcl_factor">cfl_factor</a>
2787* dt_crit where dt_crit is the maximum timestep allowed by the CFL and
2788diffusion condition. Next it is examined whether dt_new exceeds or
2789falls below the
2790value of the previous timestep by at
2791least +5 % / -2%. If it is smaller, <span style="font-weight: bold;">dt</span>
2792= dt_new is immediately used for the next timestep. If it is larger,
2793then <span style="font-weight: bold;">dt </span>=
27941.02 * dt_prev
2795(previous timestep) is used as the new timestep, however the time
2796step is only increased if the last change of the time step is dated
2797back at
2798least 30 iterations. If dt_new is located in the interval mentioned
2799above, then dt
2800does not change at all. By doing so, permanent time step changes as
2801well as large
2802sudden changes (increases) in the time step are avoided.</p>
2803
2804
2805
2806
2807 </td>
2808
2809
2810
2811
2812
2813    </tr>
2814
2815
2816
2817
2818 <tr>
2819
2820
2821
2822
2823 <td style="vertical-align: top;">
2824     
2825     
2826     
2827     
2828      <p><a name="dt_pr_1d"></a><b>dt_pr_1d</b></p>
2829
2830
2831
2832
2833
2834      </td>
2835
2836
2837
2838
2839 <td style="vertical-align: top;">R</td>
2840
2841
2842
2843
2844
2845      <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
2846
2847
2848
2849
2850
2851      <td style="vertical-align: top;"> 
2852     
2853     
2854     
2855     
2856      <p>Temporal
2857interval of vertical profile output of the 1D-model
2858(in s).&nbsp; </p>
2859
2860
2861
2862
2863 
2864     
2865     
2866     
2867     
2868      <p>Data are written in ASCII
2869format to file <a href="chapter_3.4.html#LIST_PROFIL_1D">LIST_PROFIL_1D</a>.
2870This parameter is only in effect if the 1d-model has been switched on
2871for the
2872initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
2873= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
2874
2875
2876
2877
2878
2879      </td>
2880
2881
2882
2883
2884 </tr>
2885
2886
2887
2888
2889 <tr>
2890
2891
2892
2893
2894 <td style="vertical-align: top;"> 
2895     
2896     
2897     
2898     
2899      <p><a name="dt_run_control_1d"></a><b>dt_run_control_1d</b></p>
2900
2901
2902
2903
2904
2905      </td>
2906
2907
2908
2909
2910 <td style="vertical-align: top;">R</td>
2911
2912
2913
2914
2915
2916      <td style="vertical-align: top;"><span style="font-style: italic;">60.0</span></td>
2917
2918
2919
2920
2921 <td style="vertical-align: top;"> 
2922     
2923     
2924     
2925     
2926      <p>Temporal interval of
2927runtime control output of the 1d-model
2928(in s).&nbsp; </p>
2929
2930
2931
2932
2933 
2934     
2935     
2936     
2937     
2938      <p>Data are written in ASCII
2939format to file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.
2940This parameter is only in effect if the 1d-model is switched on for the
2941initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
2942= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
2943
2944
2945
2946
2947
2948      </td>
2949
2950
2951
2952
2953 </tr>
2954
2955
2956
2957
2958 <tr>
2959
2960
2961
2962
2963 <td style="vertical-align: top;"> 
2964     
2965     
2966     
2967     
2968      <p><a name="dx"></a><b>dx</b></p>
2969
2970
2971
2972
2973
2974      </td>
2975
2976
2977
2978
2979 <td style="vertical-align: top;">R</td>
2980
2981
2982
2983
2984
2985      <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
2986
2987
2988
2989
2990 <td style="vertical-align: top;"> 
2991     
2992     
2993     
2994     
2995      <p>Horizontal grid
2996spacing along the x-direction (in m).&nbsp; </p>
2997
2998
2999
3000
3001 
3002     
3003     
3004     
3005     
3006      <p>Along
3007x-direction only a constant grid spacing is allowed.</p>
3008
3009
3010
3011
3012     
3013     
3014     
3015     
3016      <p>For <a href="chapter_3.8.html">coupled runs</a> this parameter must be&nbsp;equal in both parameter files <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2"><span style="font-family: mon;"></span>PARIN</font></a>
3017and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
3018
3019
3020
3021
3022 </td>
3023
3024
3025
3026
3027
3028    </tr>
3029
3030
3031
3032
3033 <tr>
3034
3035
3036
3037
3038 <td style="vertical-align: top;">
3039     
3040     
3041     
3042     
3043      <p><a name="dy"></a><b>dy</b></p>
3044
3045
3046
3047
3048
3049      </td>
3050
3051
3052
3053
3054 <td style="vertical-align: top;">R</td>
3055
3056
3057
3058
3059
3060      <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
3061
3062
3063
3064
3065 <td style="vertical-align: top;"> 
3066     
3067     
3068     
3069     
3070      <p>Horizontal grid
3071spacing along the y-direction (in m).&nbsp; </p>
3072
3073
3074
3075
3076 
3077     
3078     
3079     
3080     
3081      <p>Along y-direction only a constant grid spacing is allowed.</p>
3082
3083
3084
3085
3086     
3087     
3088     
3089     
3090      <p>For <a href="chapter_3.8.html">coupled runs</a> this parameter must be&nbsp;equal in both parameter files <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2"><span style="font-family: mon;"></span>PARIN</font></a>
3091and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
3092
3093
3094
3095
3096 </td>
3097
3098
3099
3100
3101
3102    </tr>
3103
3104
3105
3106
3107 <tr>
3108
3109
3110
3111
3112 <td style="vertical-align: top;">
3113     
3114     
3115     
3116     
3117      <p><a name="dz"></a><b>dz</b></p>
3118
3119
3120
3121
3122
3123      </td>
3124
3125
3126
3127
3128 <td style="vertical-align: top;">R</td>
3129
3130
3131
3132
3133
3134      <td style="vertical-align: top;"><br>
3135
3136
3137
3138
3139 </td>
3140
3141
3142
3143
3144 <td style="vertical-align: top;"> 
3145     
3146     
3147     
3148     
3149      <p>Vertical grid
3150spacing (in m).&nbsp; </p>
3151
3152
3153
3154
3155 
3156     
3157     
3158     
3159     
3160      <p>This parameter must be
3161assigned by the user, because no
3162default value is given.<br>
3163
3164
3165
3166
3167 </p>
3168
3169
3170
3171
3172 
3173     
3174     
3175     
3176     
3177      <p>By default, the
3178model uses constant grid spacing along z-direction, but it can be
3179stretched using the parameters <a href="#dz_stretch_level">dz_stretch_level</a>
3180and <a href="#dz_stretch_factor">dz_stretch_factor</a>.
3181In case of stretching, a maximum allowed grid spacing can be given by <a href="#dz_max">dz_max</a>.<br>
3182
3183
3184
3185
3186 </p>
3187
3188
3189
3190
3191 
3192     
3193     
3194     
3195     
3196      <p>Assuming
3197a constant <span style="font-weight: bold;">dz</span>,
3198the scalar levels (zu) are calculated directly by:&nbsp; </p>
3199
3200
3201
3202
3203
3204     
3205     
3206     
3207     
3208      <ul>
3209
3210
3211
3212
3213 
3214       
3215       
3216       
3217       
3218        <p>zu(0) = - dz * 0.5&nbsp; <br>
3219
3220
3221
3222
3223
3224zu(1) = dz * 0.5</p>
3225
3226
3227
3228
3229 
3230     
3231     
3232     
3233     
3234      </ul>
3235
3236
3237
3238
3239 
3240     
3241     
3242     
3243     
3244      <p>The w-levels lie
3245half between them:&nbsp; </p>
3246
3247
3248
3249
3250 
3251     
3252     
3253     
3254     
3255      <ul>
3256
3257
3258
3259
3260 
3261       
3262       
3263       
3264       
3265        <p>zw(k) =
3266( zu(k) + zu(k+1) ) * 0.5</p>
3267
3268
3269
3270
3271 
3272     
3273     
3274     
3275     
3276      </ul>
3277
3278
3279
3280
3281 </td>
3282
3283
3284
3285
3286 </tr>
3287
3288
3289
3290
3291
3292    <tr>
3293
3294
3295
3296
3297      <td style="vertical-align: top;"><a name="dz_max"></a><span style="font-weight: bold;">dz_max</span></td>
3298
3299
3300
3301
3302      <td style="vertical-align: top;">R</td>
3303
3304
3305
3306
3307      <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
3308
3309
3310
3311
3312      <td style="vertical-align: top;">Allowed maximum vertical grid
3313spacing (in m).<br>
3314
3315
3316
3317
3318      <br>
3319
3320
3321
3322
3323If the vertical grid is stretched
3324(see <a href="#dz_stretch_factor">dz_stretch_factor</a>
3325and <a href="#dz_stretch_level">dz_stretch_level</a>),
3326      <span style="font-weight: bold;">dz_max</span> can
3327be used to limit the vertical grid spacing.</td>
3328
3329
3330
3331
3332    </tr>
3333
3334
3335
3336
3337    <tr>
3338
3339
3340
3341
3342
3343      <td style="vertical-align: top;"> 
3344     
3345     
3346     
3347     
3348      <p><a name="dz_stretch_factor"></a><b>dz_stretch_factor</b></p>
3349
3350
3351
3352
3353
3354      </td>
3355
3356
3357
3358
3359 <td style="vertical-align: top;">R</td>
3360
3361
3362
3363
3364
3365      <td style="vertical-align: top;"><span style="font-style: italic;">1.08</span></td>
3366
3367
3368
3369
3370 <td style="vertical-align: top;"> 
3371     
3372     
3373     
3374     
3375      <p>Stretch factor for a
3376vertically stretched grid (see <a href="#dz_stretch_level">dz_stretch_level</a>).&nbsp;
3377      </p>
3378
3379
3380
3381
3382 
3383     
3384     
3385     
3386     
3387      <p>The stretch factor should not exceed a value of
3388approx. 1.10 -
33891.12, otherwise the discretization errors due to the stretched grid not
3390negligible any more. (refer Kalnay de Rivas)</p>
3391
3392
3393
3394
3395 </td>
3396
3397
3398
3399
3400 </tr>
3401
3402
3403
3404
3405
3406    <tr>
3407
3408
3409
3410
3411 <td style="vertical-align: top;"> 
3412     
3413     
3414     
3415     
3416      <p><a name="dz_stretch_level"></a><b>dz_stretch_level</b></p>
3417
3418
3419
3420
3421
3422      </td>
3423
3424
3425
3426
3427 <td style="vertical-align: top;">R</td>
3428
3429
3430
3431
3432
3433      <td style="vertical-align: top;"><span style="font-style: italic;">100000.0</span><br>
3434
3435
3436
3437
3438 </td>
3439
3440
3441
3442
3443
3444      <td style="vertical-align: top;"> 
3445     
3446     
3447     
3448     
3449      <p>Height level
3450above/below which the grid is to be stretched
3451vertically (in m).&nbsp; </p>
3452
3453
3454
3455
3456 
3457     
3458     
3459     
3460     
3461      <p>For <a href="chapter_4.1.html#ocean">ocean</a> = .F., <b>dz_stretch_level </b>is the height level (in m)&nbsp;<span style="font-weight: bold;">above </span>which the grid is to be stretched
3462vertically. The vertical grid
3463spacings <a href="#dz">dz</a>
3464above this level are calculated as&nbsp; </p>
3465
3466
3467
3468
3469 
3470     
3471     
3472     
3473     
3474      <ul>
3475
3476
3477
3478
3479 
3480       
3481       
3482       
3483       
3484        <p><b>dz</b>(k+1)
3485= <b>dz</b>(k) * <a href="#dz_stretch_factor">dz_stretch_factor</a></p>
3486
3487
3488
3489
3490
3491     
3492     
3493     
3494     
3495      </ul>
3496
3497
3498
3499
3500 
3501     
3502     
3503     
3504     
3505      <p>and used as spacings for the scalar levels (zu).
3506The
3507w-levels are then defined as:&nbsp; </p>
3508
3509
3510
3511
3512 
3513     
3514     
3515     
3516     
3517      <ul>
3518
3519
3520
3521
3522 
3523       
3524       
3525       
3526       
3527        <p>zw(k)
3528= ( zu(k) + zu(k+1) ) * 0.5.
3529
3530 
3531     
3532      </p>
3533
3534
3535     
3536     
3537      </ul>
3538
3539
3540     
3541     
3542      <p>For <a href="#ocean">ocean</a> = .T., <b>dz_stretch_level </b>is the height level (in m, negative) <span style="font-weight: bold;">below</span> which the grid is to be stretched
3543vertically. The vertical grid
3544spacings <a href="chapter_4.1.html#dz">dz</a> below this level are calculated correspondingly as
3545
3546 
3547     
3548      </p>
3549
3550
3551     
3552     
3553      <ul>
3554
3555
3556       
3557       
3558        <p><b>dz</b>(k-1)
3559= <b>dz</b>(k) * <a href="chapter_4.1.html#dz_stretch_factor">dz_stretch_factor</a>.</p>
3560
3561
3562     
3563     
3564      </ul>
3565
3566
3567
3568
3569 </td>
3570
3571
3572
3573
3574 </tr>
3575
3576
3577
3578
3579
3580    <tr>
3581
3582
3583
3584      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_init"></a>e_init</span></td>
3585
3586
3587
3588      <td style="vertical-align: top;">R</td>
3589
3590
3591
3592      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
3593
3594
3595
3596      <td>Initial subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
3597
3598
3599
3600
3601
3602      <br>
3603
3604
3605
3606
3607This
3608option prescribes an initial&nbsp;subgrid-scale TKE from which the initial diffusion coefficients K<sub>m</sub> and K<sub>h</sub> will be calculated if <span style="font-weight: bold;">e_init</span> is positive. This option only has an effect if&nbsp;<a href="#km_constant">km_constant</a> is not set.</td>
3609
3610
3611
3612    </tr>
3613
3614
3615
3616    <tr>
3617
3618
3619
3620
3621 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_min"></a>e_min</span></td>
3622
3623
3624
3625
3626
3627      <td style="vertical-align: top;">R</td>
3628
3629
3630
3631
3632 <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
3633
3634
3635
3636
3637 <td>Minimum
3638subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
3639
3640
3641
3642
3643
3644      <br>
3645
3646
3647
3648
3649This
3650option&nbsp;adds artificial viscosity to the flow by ensuring that
3651the
3652subgrid-scale TKE does not fall below the minimum threshold <span style="font-weight: bold;">e_min</span>.</td>
3653
3654
3655
3656
3657 </tr>
3658
3659
3660
3661
3662
3663    <tr>
3664
3665
3666
3667
3668 <td style="vertical-align: top;"> 
3669     
3670     
3671     
3672     
3673      <p><a name="end_time_1d"></a><b>end_time_1d</b></p>
3674
3675
3676
3677
3678
3679      </td>
3680
3681
3682
3683
3684 <td style="vertical-align: top;">R</td>
3685
3686
3687
3688
3689
3690      <td style="vertical-align: top;"><span style="font-style: italic;">864000.0</span><br>
3691
3692
3693
3694
3695 </td>
3696
3697
3698
3699
3700
3701      <td style="vertical-align: top;"> 
3702     
3703     
3704     
3705     
3706      <p>Time to be
3707simulated for the 1d-model (in s).&nbsp; </p>
3708
3709
3710
3711
3712 
3713     
3714     
3715     
3716     
3717      <p>The
3718default value corresponds to a simulated time of 10 days.
3719Usually, after such a period the inertia oscillations have completely
3720decayed and the solution of the 1d-model can be regarded as stationary
3721(see <a href="#damp_level_1d">damp_level_1d</a>).
3722This parameter is only in effect if the 1d-model is switched on for the
3723initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
3724= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
3725
3726
3727
3728
3729
3730      </td>
3731
3732
3733
3734
3735 </tr>
3736
3737
3738
3739
3740 <tr>
3741
3742
3743
3744
3745 <td style="vertical-align: top;"> 
3746     
3747     
3748     
3749     
3750      <p><a name="fft_method"></a><b>fft_method</b></p>
3751
3752
3753
3754
3755
3756      </td>
3757
3758
3759
3760
3761 <td style="vertical-align: top;">C * 20</td>
3762
3763
3764
3765
3766
3767      <td style="vertical-align: top;"><span style="font-style: italic;">'system-</span><br style="font-style: italic;">
3768
3769
3770
3771
3772 <span style="font-style: italic;">specific'</span></td>
3773
3774
3775
3776
3777
3778      <td style="vertical-align: top;"> 
3779     
3780     
3781     
3782     
3783      <p>FFT-method to
3784be used.<br>
3785
3786
3787
3788
3789 </p>
3790
3791
3792
3793
3794 
3795     
3796     
3797     
3798     
3799      <p><br>
3800
3801
3802
3803
3804
3805The fast fourier transformation (FFT) is used for solving the
3806perturbation pressure equation with a direct method (see <a href="chapter_4.2.html#psolver">psolver</a>)
3807and for calculating power spectra (see optional software packages,
3808section <a href="chapter_4.2.html#spectra_package">4.2</a>).</p>
3809
3810
3811
3812
3813
3814     
3815     
3816     
3817     
3818      <p><br>
3819
3820
3821
3822
3823
3824By default, system-specific, optimized routines from external
3825vendor libraries are used. However, these are available only on certain
3826computers and there are more or less severe restrictions concerning the
3827number of gridpoints to be used with them.<br>
3828
3829
3830
3831
3832 </p>
3833
3834
3835
3836
3837 
3838     
3839     
3840     
3841     
3842      <p>There
3843are two other PALM internal methods available on every
3844machine (their respective source code is part of the PALM source code):</p>
3845
3846
3847
3848
3849
3850     
3851     
3852     
3853     
3854      <p>1.: The <span style="font-weight: bold;">Temperton</span>-method
3855from Clive Temperton (ECWMF) which is computationally very fast and
3856switched on with <b>fft_method</b> = <span style="font-style: italic;">'temperton-algorithm'</span>.
3857The number of horizontal gridpoints (nx+1, ny+1) to be used with this
3858method must be composed of prime factors 2, 3 and 5.<br>
3859
3860
3861
3862
3863 </p>
3864
3865
3866
3867
3868
38692.: The <span style="font-weight: bold;">Singleton</span>-method
3870which is very slow but has no restrictions concerning the number of
3871gridpoints to be used with, switched on with <b>fft_method</b>
3872= <span style="font-style: italic;">'singleton-algorithm'</span>.
3873      </td>
3874
3875
3876
3877
3878 </tr>
3879
3880
3881
3882
3883 <tr>
3884
3885
3886
3887
3888 <td style="vertical-align: top;"> 
3889     
3890     
3891     
3892     
3893      <p><a name="galilei_transformation"></a><b>galilei_transformation</b></p>
3894
3895
3896
3897
3898
3899      </td>
3900
3901
3902
3903
3904 <td style="vertical-align: top;">L</td>
3905
3906
3907
3908
3909
3910      <td style="vertical-align: top;"><i>.F.</i></td>
3911
3912
3913
3914
3915
3916      <td style="vertical-align: top;">Application of a
3917Galilei-transformation to the
3918coordinate
3919system of the model.<br>
3920
3921
3922
3923
3924     
3925     
3926     
3927     
3928      <p>With <b>galilei_transformation</b>
3929= <i>.T.,</i> a so-called
3930Galilei-transformation is switched on which ensures that the coordinate
3931system of the model is moved along with the geostrophical wind.
3932Alternatively, the model domain can be moved along with the averaged
3933horizontal wind (see <a href="#use_ug_for_galilei_tr">use_ug_for_galilei_tr</a>,
3934this can and will naturally change in time). With this method,
3935numerical inaccuracies of the Piascek - Williams - scheme (concerns in
3936particular the momentum advection) are minimized. Beyond that, in the
3937majority of cases the lower relative velocities in the moved system
3938permit a larger time step (<a href="#dt">dt</a>).
3939Switching the transformation on is only worthwhile if the geostrophical
3940wind (ug, vg)
3941and the averaged horizontal wind clearly deviate from the value 0. In
3942each case, the distance the coordinate system has been moved is written
3943to the file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.&nbsp;
3944      </p>
3945
3946
3947
3948
3949 
3950     
3951     
3952     
3953     
3954      <p>Non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
3955and <a href="#bc_ns">bc_ns</a>), the specification
3956of a gestrophic
3957wind that is not constant with height
3958as well as e.g. stationary inhomogeneities at the bottom boundary do
3959not allow the use of this transformation.</p>
3960
3961
3962
3963
3964 </td>
3965
3966
3967
3968
3969 </tr>
3970
3971
3972
3973
3974
3975    <tr>
3976
3977
3978
3979
3980 <td style="vertical-align: top;"> 
3981     
3982     
3983     
3984     
3985      <p><a name="grid_matching"></a><b>grid_matching</b></p>
3986
3987
3988
3989
3990
3991      </td>
3992
3993
3994
3995
3996 <td style="vertical-align: top;">C * 6</td>
3997
3998
3999
4000
4001
4002      <td style="vertical-align: top;"><span style="font-style: italic;">'match'</span></td>
4003
4004
4005
4006
4007 <td style="vertical-align: top;">Variable to adjust the
4008subdomain
4009sizes in parallel runs.<br>
4010
4011
4012
4013
4014 <br>
4015
4016
4017
4018
4019
4020For <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>,
4021the subdomains are forced to have an identical
4022size on all processors. In this case the processor numbers in the
4023respective directions of the virtual processor net must fulfill certain
4024divisor conditions concerning the grid point numbers in the three
4025directions (see <a href="#nx">nx</a>, <a href="#ny">ny</a>
4026and <a href="#nz">nz</a>).
4027Advantage of this method is that all PEs bear the same computational
4028load.<br>
4029
4030
4031
4032
4033 <br>
4034
4035
4036
4037
4038
4039There is no such restriction by default, because then smaller
4040subdomains are allowed on those processors which
4041form the right and/or north boundary of the virtual processor grid. On
4042all other processors the subdomains are of same size. Whether smaller
4043subdomains are actually used, depends on the number of processors and
4044the grid point numbers used. Information about the respective settings
4045are given in file <a href="file:///home/raasch/public_html/PALM_group/home/raasch/public_html/PALM_group/doc/app/chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.<br>
4046
4047
4048
4049
4050
4051      <br>
4052
4053
4054
4055
4056
4057When using a multi-grid method for solving the Poisson equation (see <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">psolver</a>)
4058only <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>
4059is allowed.<br>
4060
4061
4062
4063
4064 <br>
4065
4066
4067
4068
4069 <b>Note:</b><br>
4070
4071
4072
4073
4074
4075In some cases for small processor numbers there may be a very bad load
4076balancing among the
4077processors which may reduce the performance of the code.</td>
4078
4079
4080
4081
4082 </tr>
4083
4084
4085
4086
4087
4088    <tr>
4089
4090
4091
4092
4093 <td style="vertical-align: top;"><a name="inflow_disturbance_begin"></a><b>inflow_disturbance_<br>
4094
4095
4096
4097
4098
4099begin</b></td>
4100
4101
4102
4103
4104 <td style="vertical-align: top;">I</td>
4105
4106
4107
4108
4109
4110      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(10,</span><br style="font-style: italic;">
4111
4112
4113
4114
4115 <span style="font-style: italic;">nx/2 or ny/2)</span></td>
4116
4117
4118
4119
4120
4121      <td style="vertical-align: top;">Lower
4122limit of the horizontal range for which random perturbations are to be
4123imposed on the horizontal velocity field (gridpoints).<br>
4124
4125
4126
4127
4128 <br>
4129
4130
4131
4132
4133
4134If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
4135or <a href="#bc_ns">bc_ns</a>),
4136this parameter gives the gridpoint number (counted horizontally from
4137the inflow)&nbsp; from which on perturbations are imposed on the
4138horizontal velocity field. Perturbations must be switched on with
4139parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
4140
4141
4142
4143
4144
4145    </tr>
4146
4147
4148
4149
4150 <tr>
4151
4152
4153
4154
4155 <td style="vertical-align: top;"><a name="inflow_disturbance_end"></a><b>inflow_disturbance_<br>
4156
4157
4158
4159
4160
4161end</b></td>
4162
4163
4164
4165
4166 <td style="vertical-align: top;">I</td>
4167
4168
4169
4170
4171
4172      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(100,</span><br style="font-style: italic;">
4173
4174
4175
4176
4177 <span style="font-style: italic;">3/4*nx or</span><br style="font-style: italic;">
4178
4179
4180
4181
4182 <span style="font-style: italic;">3/4*ny)</span></td>
4183
4184
4185
4186
4187 <td style="vertical-align: top;">Upper
4188limit of the horizontal range for which random perturbations are
4189to be imposed on the horizontal velocity field (gridpoints).<br>
4190
4191
4192
4193
4194 <br>
4195
4196
4197
4198
4199
4200If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
4201or <a href="#bc_ns">bc_ns</a>),
4202this parameter gives the gridpoint number (counted horizontally from
4203the inflow)&nbsp; unto which perturbations are imposed on the
4204horizontal
4205velocity field. Perturbations must be switched on with parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
4206
4207
4208
4209
4210
4211    </tr>
4212
4213
4214
4215
4216 <tr>
4217
4218
4219
4220
4221 <td style="vertical-align: top;">
4222     
4223     
4224     
4225     
4226      <p><a name="initializing_actions"></a><b>initializing_actions</b></p>
4227
4228
4229
4230
4231
4232      </td>
4233
4234
4235
4236
4237 <td style="vertical-align: top;">C * 100</td>
4238
4239
4240
4241
4242
4243      <td style="vertical-align: top;"><br>
4244
4245
4246
4247
4248 </td>
4249
4250
4251
4252
4253 <td style="vertical-align: top;"> 
4254     
4255     
4256     
4257     
4258      <p style="font-style: normal;">Initialization actions
4259to be carried out.&nbsp; </p>
4260
4261
4262
4263
4264 
4265     
4266     
4267     
4268     
4269      <p style="font-style: normal;">This parameter does not have a
4270default value and therefore must be assigned with each model run. For
4271restart runs <b>initializing_actions</b> = <span style="font-style: italic;">'read_restart_data'</span>
4272must be set. For the initial run of a job chain the following values
4273are allowed:&nbsp; </p>
4274
4275
4276
4277
4278 
4279     
4280     
4281     
4282     
4283      <p style="font-style: normal;"><span style="font-style: italic;">'set_constant_profiles'</span>
4284      </p>
4285
4286
4287
4288
4289 
4290     
4291     
4292     
4293     
4294      <ul>
4295
4296
4297
4298
4299 
4300       
4301       
4302       
4303       
4304        <p>A horizontal wind profile consisting
4305of linear sections (see <a href="#ug_surface">ug_surface</a>,
4306        <a href="#ug_vertical_gradient">ug_vertical_gradient</a>,
4307        <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>
4308and <a href="#vg_surface">vg_surface</a>, <a href="#vg_vertical_gradient">vg_vertical_gradient</a>,
4309        <a href="#vg_vertical_gradient_level">vg_vertical_gradient_level</a>,
4310respectively) as well as a vertical temperature (humidity) profile
4311consisting of
4312linear sections (see <a href="#pt_surface">pt_surface</a>,
4313        <a href="#pt_vertical_gradient">pt_vertical_gradient</a>,
4314        <a href="#q_surface">q_surface</a>
4315and <a href="#q_vertical_gradient">q_vertical_gradient</a>)
4316are assumed as initial profiles. The subgrid-scale TKE is set to 0 but K<sub>m</sub>
4317and K<sub>h</sub> are set to very small values because
4318otherwise no TKE
4319would be generated.</p>
4320
4321
4322
4323
4324 
4325     
4326     
4327     
4328     
4329      </ul>
4330
4331
4332
4333
4334 
4335     
4336     
4337     
4338     
4339      <p style="font-style: italic;">'set_1d-model_profiles' </p>
4340
4341
4342
4343
4344
4345     
4346     
4347     
4348     
4349      <ul>
4350
4351
4352
4353
4354 
4355       
4356       
4357       
4358       
4359        <p>The arrays of the 3d-model are initialized with
4360the
4361(stationary) solution of the 1d-model. These are the variables e, kh,
4362km, u, v and with Prandtl layer switched on rif, us, usws, vsws. The
4363temperature (humidity) profile consisting of linear sections is set as
4364for 'set_constant_profiles' and assumed as constant in time within the
43651d-model. For steering of the 1d-model a set of parameters with suffix
4366"_1d" (e.g. <a href="#end_time_1d">end_time_1d</a>,
4367        <a href="#damp_level_1d">damp_level_1d</a>)
4368is available.</p>
4369
4370
4371
4372
4373 
4374     
4375     
4376     
4377     
4378      </ul>
4379
4380
4381
4382
4383 
4384     
4385     
4386     
4387     
4388      <p><span style="font-style: italic;">'by_user'</span></p>
4389
4390
4391
4392
4393     
4394     
4395     
4396     
4397      <p style="margin-left: 40px;">The initialization of the arrays
4398of the 3d-model is under complete control of the user and has to be
4399done in routine <a href="chapter_3.5.1.html#user_init_3d_model">user_init_3d_model</a>
4400of the user-interface.<span style="font-style: italic;"></span></p>
4401
4402
4403
4404
4405     
4406     
4407     
4408     
4409      <p><span style="font-style: italic;">'initialize_vortex'</span>
4410      </p>
4411
4412
4413
4414
4415 
4416     
4417     
4418     
4419     
4420      <div style="margin-left: 40px;">The initial
4421velocity field of the
44223d-model corresponds to a
4423Rankine-vortex with vertical axis. This setting may be used to test
4424advection schemes. Free-slip boundary conditions for u and v (see <a href="#bc_uv_b">bc_uv_b</a>, <a href="#bc_uv_t">bc_uv_t</a>)
4425are necessary. In order not to distort the vortex, an initial
4426horizontal wind profile constant
4427with height is necessary (to be set by <b>initializing_actions</b>
4428= <span style="font-style: italic;">'set_constant_profiles'</span>)
4429and some other conditions have to be met (neutral stratification,
4430diffusion must be
4431switched off, see <a href="#km_constant">km_constant</a>).
4432The center of the vortex is located at jc = (nx+1)/2. It
4433extends from k = 0 to k = nz+1. Its radius is 8 * <a href="#dx">dx</a>
4434and the exponentially decaying part ranges to 32 * <a href="#dx">dx</a>
4435(see init_rankine.f90). </div>
4436
4437
4438
4439
4440 
4441     
4442     
4443     
4444     
4445      <p><span style="font-style: italic;">'initialize_ptanom'</span>
4446      </p>
4447
4448
4449
4450
4451 
4452     
4453     
4454     
4455     
4456      <ul>
4457
4458
4459
4460
4461 
4462       
4463       
4464       
4465       
4466        <p>A 2d-Gauss-like shape disturbance
4467(x,y) is added to the
4468initial temperature field with radius 10.0 * <a href="#dx">dx</a>
4469and center at jc = (nx+1)/2. This may be used for tests of scalar
4470advection schemes
4471(see <a href="#scalar_advec">scalar_advec</a>).
4472Such tests require a horizontal wind profile constant with hight and
4473diffusion
4474switched off (see <span style="font-style: italic;">'initialize_vortex'</span>).
4475Additionally, the buoyancy term
4476must be switched of in the equation of motion&nbsp; for w (this
4477requires the user to comment out the call of <span style="font-family: monospace;">buoyancy</span> in the
4478source code of <span style="font-family: monospace;">prognostic_equations.f90</span>).</p>
4479
4480
4481
4482
4483
4484     
4485     
4486     
4487     
4488      </ul>
4489
4490
4491
4492
4493 
4494     
4495     
4496     
4497     
4498      <p style="font-style: normal;">Values may be
4499combined, e.g. <b>initializing_actions</b> = <span style="font-style: italic;">'set_constant_profiles
4500initialize_vortex'</span>, but the values of <span style="font-style: italic;">'set_constant_profiles'</span>,
4501      <span style="font-style: italic;">'set_1d-model_profiles'</span>
4502, and <span style="font-style: italic;">'by_user'</span>
4503must not be given at the same time.</p>
4504
4505
4506
4507
4508 
4509     
4510     
4511     
4512     
4513      <p style="font-style: italic;"> </p>
4514
4515
4516
4517
4518 </td>
4519
4520
4521
4522
4523 </tr>
4524
4525
4526
4527
4528
4529    <tr>
4530
4531
4532
4533
4534 <td style="vertical-align: top;"> 
4535     
4536     
4537     
4538     
4539      <p><a name="km_constant"></a><b>km_constant</b></p>
4540
4541
4542
4543
4544
4545      </td>
4546
4547
4548
4549
4550 <td style="vertical-align: top;">R</td>
4551
4552
4553
4554
4555
4556      <td style="vertical-align: top;"><i>variable<br>
4557
4558
4559
4560
4561
4562(computed from TKE)</i></td>
4563
4564
4565
4566
4567 <td style="vertical-align: top;"> 
4568     
4569     
4570     
4571     
4572      <p>Constant eddy
4573diffusivities are used (laminar
4574simulations).&nbsp; </p>
4575
4576
4577
4578
4579 
4580     
4581     
4582     
4583     
4584      <p>If this parameter is
4585specified, both in the 1d and in the
45863d-model constant values for the eddy diffusivities are used in
4587space and time with K<sub>m</sub> = <b>km_constant</b>
4588and K<sub>h</sub> = K<sub>m</sub> / <a href="chapter_4.2.html#prandtl_number">prandtl_number</a>.
4589The prognostic equation for the subgrid-scale TKE is switched off.
4590Constant eddy diffusivities are only allowed with the Prandtl layer (<a href="#prandtl_layer">prandtl_layer</a>)
4591switched off.</p>
4592
4593
4594
4595
4596 </td>
4597
4598
4599
4600
4601 </tr>
4602
4603
4604
4605
4606 <tr>
4607
4608
4609
4610
4611 <td style="vertical-align: top;"> 
4612     
4613     
4614     
4615     
4616      <p><a name="km_damp_max"></a><b>km_damp_max</b></p>
4617
4618
4619
4620
4621
4622      </td>
4623
4624
4625
4626
4627 <td style="vertical-align: top;">R</td>
4628
4629
4630
4631
4632
4633      <td style="vertical-align: top;"><span style="font-style: italic;">0.5*(dx
4634or dy)</span></td>
4635
4636
4637
4638
4639 <td style="vertical-align: top;">Maximum
4640diffusivity used for filtering the velocity field in the vicinity of
4641the outflow (in m<sup>2</sup>/s).<br>
4642
4643
4644
4645
4646 <br>
4647
4648
4649
4650
4651
4652When using non-cyclic lateral boundaries (see <a href="#bc_lr">bc_lr</a>
4653or <a href="#bc_ns">bc_ns</a>),
4654a smoothing has to be applied to the
4655velocity field in the vicinity of the outflow in order to suppress any
4656reflections of outgoing disturbances. Smoothing is done by increasing
4657the eddy diffusivity along the horizontal direction which is
4658perpendicular to the outflow boundary. Only velocity components
4659parallel to the outflow boundary are filtered (e.g. v and w, if the
4660outflow is along x). Damping is applied from the bottom to the top of
4661the domain.<br>
4662
4663
4664
4665
4666 <br>
4667
4668
4669
4670
4671
4672The horizontal range of the smoothing is controlled by <a href="#outflow_damping_width">outflow_damping_width</a>
4673which defines the number of gridpoints (counted from the outflow
4674boundary) from where on the smoothing is applied. Starting from that
4675point, the eddy diffusivity is linearly increased (from zero to its
4676maximum value given by <span style="font-weight: bold;">km_damp_max</span>)
4677until half of the damping range width, from where it remains constant
4678up to the outflow boundary. If at a certain grid point the eddy
4679diffusivity calculated from the flow field is larger than as described
4680above, it is used instead.<br>
4681
4682
4683
4684
4685 <br>
4686
4687
4688
4689
4690
4691The default value of <span style="font-weight: bold;">km_damp_max</span>
4692has been empirically proven to be sufficient.</td>
4693
4694
4695
4696
4697 </tr>
4698
4699
4700
4701
4702 <tr><td><a name="lad_surface"></a><span style="font-weight: bold;">lad_surface</span></td><td>R</td><td><span style="font-style: italic;">0.0</span></td><td>Surface value of the leaf area density (in m<sup>2</sup>/m<sup>3</sup>).<br><br>This
4703parameter assigns the value of the leaf area density <span style="font-weight: bold;">lad</span> at the surface (k=0)<b>.</b> Starting from this value,
4704the leaf area density profile is constructed with <a href="chapter_4.1.html#lad_vertical_gradient">lad_vertical_gradient</a>
4705and <a href="chapter_4.1.html#lad_vertical_gradient_level">lad_vertical_gradient_level
4706      </a>.</td></tr><tr><td><a name="lad_vertical_gradient"></a><span style="font-weight: bold;">lad_vertical_gradient</span></td><td>R (10)</td><td><span style="font-style: italic;">10 * 0.0</span></td><td>Gradient(s) of the leaf area density (in&nbsp;m<sup>2</sup>/m<sup>4</sup>).<br><br><p>This leaf area density gradient
4707holds starting from the height&nbsp;
4708level defined by <a href="chapter_4.1.html#lad_vertical_gradient_level">lad_vertical_gradient_level</a>
4709(precisely: for all uv levels k where zu(k) &gt; lad_vertical_gradient_level, lad(k) is set: lad(k) = lad(k-1) + dzu(k) * <b>lad_vertical_gradient</b>)
4710up to the level defined by <a href="#pch_index">pch_index</a>. Above that level lad(k) will automatically set to 0.0. A total of 10 different gradients for 11 height intervals (10 intervals
4711if <a href="chapter_4.1.html#lad_vertical_gradient_level">lad_vertical_gradient_level</a>(1)
4712= <i>0.0</i>) can be assigned. The leaf area density at the surface is
4713assigned via <a href="chapter_4.1.html#lad_surface">lad_surface</a>.&nbsp;
4714      </p></td></tr><tr><td><a name="lad_vertical_gradient_level"></a><span style="font-weight: bold;">lad_vertical_gradient_level</span></td><td>R (10)</td><td><span style="font-style: italic;">10 * 0.0</span></td><td>Height level from which on the&nbsp;gradient
4715of the leaf area density defined by <a href="chapter_4.1.html#lad_vertical_gradient">lad_vertical_gradient_level</a>
4716is effective (in m).<br><br>The height levels have to be assigned in ascending order. The
4717default values result in a leaf area density that is constant with height uup to the top of the plant canopy layer defined by <a href="#pch_index">pch_index</a>. For the piecewise construction of temperature profiles see <a href="chapter_4.1.html#lad_vertical_gradient">lad_vertical_gradient</a>.</td></tr><tr>
4718
4719
4720
4721
4722
4723      <td style="vertical-align: top;"> 
4724     
4725     
4726     
4727     
4728      <p><a name="long_filter_factor"></a><b>long_filter_factor</b></p>
4729
4730
4731
4732
4733
4734      </td>
4735
4736
4737
4738
4739 <td style="vertical-align: top;">R</td>
4740
4741
4742
4743
4744
4745      <td style="vertical-align: top;"><i>0.0</i></td>
4746
4747
4748
4749
4750
4751      <td style="vertical-align: top;"> 
4752     
4753     
4754     
4755     
4756      <p>Filter factor
4757for the so-called Long-filter.<br>
4758
4759
4760
4761
4762 </p>
4763
4764
4765
4766
4767 
4768     
4769     
4770     
4771     
4772      <p><br>
4773
4774
4775
4776
4777
4778This filter very efficiently
4779eliminates 2-delta-waves sometimes cauesed by the upstream-spline
4780scheme (see Mahrer and
4781Pielke, 1978: Mon. Wea. Rev., 106, 818-830). It works in all three
4782directions in space. A value of <b>long_filter_factor</b>
4783= <i>0.01</i>
4784sufficiently removes the small-scale waves without affecting the
4785longer waves.<br>
4786
4787
4788
4789
4790 </p>
4791
4792
4793
4794
4795 
4796     
4797     
4798     
4799     
4800      <p>By default, the filter is
4801switched off (= <i>0.0</i>).
4802It is exclusively applied to the tendencies calculated by the
4803upstream-spline scheme (see <a href="#momentum_advec">momentum_advec</a>
4804and <a href="#scalar_advec">scalar_advec</a>),
4805not to the prognostic variables themselves. At the bottom and top
4806boundary of the model domain the filter effect for vertical
48072-delta-waves is reduced. There, the amplitude of these waves is only
4808reduced by approx. 50%, otherwise by nearly 100%.&nbsp; <br>
4809
4810
4811
4812
4813
4814Filter factors with values &gt; <i>0.01</i> also
4815reduce the amplitudes
4816of waves with wavelengths longer than 2-delta (see the paper by Mahrer
4817and
4818Pielke, quoted above). </p>
4819
4820
4821
4822
4823 </td>
4824
4825
4826
4827
4828 </tr>
4829
4830
4831
4832
4833 <tr>
4834
4835
4836
4837
4838      <td style="vertical-align: top;"><a name="loop_optimization"></a><span style="font-weight: bold;">loop_optimization</span></td>
4839
4840
4841
4842
4843      <td style="vertical-align: top;">C*16</td>
4844
4845
4846
4847
4848      <td style="vertical-align: top;"><span style="font-style: italic;">see right</span></td>
4849
4850
4851
4852
4853      <td>Method used to optimize loops for solving the prognostic equations .<br>
4854
4855
4856
4857
4858      <br>
4859
4860
4861
4862
4863By
4864default, the optimization method depends on the host on which PALM is
4865running. On machines with vector-type CPUs, single 3d-loops are used to
4866calculate each tendency term of each prognostic equation, while on all
4867other machines, all prognostic equations are solved within one big loop
4868over the two horizontal indices<span style="font-family: Courier New,Courier,monospace;"> i </span>and<span style="font-family: Courier New,Courier,monospace;"> j </span>(giving a good cache uitilization).<br>
4869
4870
4871
4872
4873      <br>
4874
4875
4876
4877
4878The default behaviour can be changed by setting either <span style="font-weight: bold;">loop_optimization</span> = <span style="font-style: italic;">'vector'</span> or <span style="font-weight: bold;">loop_optimization</span> = <span style="font-style: italic;">'cache'</span>.</td>
4879
4880
4881
4882
4883    </tr>
4884
4885
4886
4887
4888    <tr>
4889
4890
4891
4892
4893
4894      <td style="vertical-align: top;"><a name="mixing_length_1d"></a><span style="font-weight: bold;">mixing_length_1d</span><br>
4895
4896
4897
4898
4899
4900      </td>
4901
4902
4903
4904
4905 <td style="vertical-align: top;">C*20<br>
4906
4907
4908
4909
4910
4911      </td>
4912
4913
4914
4915
4916 <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
4917
4918
4919
4920
4921 <span style="font-style: italic;">model'</span><br>
4922
4923
4924
4925
4926 </td>
4927
4928
4929
4930
4931
4932      <td style="vertical-align: top;">Mixing length used in the
49331d-model.<br>
4934
4935
4936
4937
4938 <br>
4939
4940
4941
4942
4943
4944By default the mixing length is calculated as in the 3d-model (i.e. it
4945depends on the grid spacing).<br>
4946
4947
4948
4949
4950 <br>
4951
4952
4953
4954
4955
4956By setting <span style="font-weight: bold;">mixing_length_1d</span>
4957= <span style="font-style: italic;">'blackadar'</span>,
4958the so-called Blackadar mixing length is used (l = kappa * z / ( 1 +
4959kappa * z / lambda ) with the limiting value lambda = 2.7E-4 * u_g / f).<br>
4960
4961
4962
4963
4964
4965      </td>
4966
4967
4968
4969
4970 </tr>
4971
4972
4973
4974
4975 <tr>
4976
4977
4978
4979
4980 <td style="vertical-align: top;"> 
4981     
4982     
4983     
4984     
4985      <p><a name="humidity"></a><b>humidity</b></p>
4986
4987
4988
4989
4990
4991      </td>
4992
4993
4994
4995
4996 <td style="vertical-align: top;">L</td>
4997
4998
4999
5000
5001
5002      <td style="vertical-align: top;"><i>.F.</i></td>
5003
5004
5005
5006
5007
5008      <td style="vertical-align: top;"> 
5009     
5010     
5011     
5012     
5013      <p>Parameter to
5014switch on the prognostic equation for specific
5015humidity q.<br>
5016
5017
5018
5019
5020 </p>
5021
5022
5023
5024
5025 
5026     
5027     
5028     
5029     
5030      <p>The initial vertical
5031profile of q can be set via parameters <a href="chapter_4.1.html#q_surface">q_surface</a>, <a href="chapter_4.1.html#q_vertical_gradient">q_vertical_gradient</a>
5032and <a href="chapter_4.1.html#q_vertical_gradient_level">q_vertical_gradient_level</a>.&nbsp;
5033Boundary conditions can be set via <a href="chapter_4.1.html#q_surface_initial_change">q_surface_initial_change</a>
5034and <a href="chapter_4.1.html#surface_waterflux">surface_waterflux</a>.<br>
5035
5036
5037
5038
5039
5040      </p>
5041
5042
5043
5044
5045
5046If the condensation scheme is switched on (<a href="chapter_4.1.html#cloud_physics">cloud_physics</a>
5047= .TRUE.), q becomes the total liquid water content (sum of specific
5048humidity and liquid water content).</td>
5049
5050
5051
5052
5053 </tr>
5054
5055
5056
5057
5058
5059    <tr>
5060
5061
5062
5063
5064 <td style="vertical-align: top;"> 
5065     
5066     
5067     
5068     
5069      <p><a name="momentum_advec"></a><b>momentum_advec</b></p>
5070
5071
5072
5073
5074
5075      </td>
5076
5077
5078
5079
5080 <td style="vertical-align: top;">C * 10</td>
5081
5082
5083
5084
5085
5086      <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
5087
5088
5089
5090
5091
5092      <td style="vertical-align: top;"> 
5093     
5094     
5095     
5096     
5097      <p>Advection
5098scheme to be used for the momentum equations.<br>
5099
5100
5101
5102
5103 <br>
5104
5105
5106
5107
5108
5109The user can choose between the following schemes:<br>
5110
5111
5112
5113
5114
5115&nbsp;<br>
5116
5117
5118
5119
5120 <br>
5121
5122
5123
5124
5125 <span style="font-style: italic;">'pw-scheme'</span><br>
5126
5127
5128
5129
5130
5131      </p>
5132
5133
5134
5135
5136 
5137     
5138     
5139     
5140     
5141      <div style="margin-left: 40px;">The scheme of
5142Piascek and
5143Williams (1970, J. Comp. Phys., 6,
5144392-405) with central differences in the form C3 is used.<br>
5145
5146
5147
5148
5149
5150If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
5151= <span style="font-style: italic;">'leapfrog+euler'</span>
5152the
5153advection scheme is - for the Euler-timestep - automatically switched
5154to an upstream-scheme.<br>
5155
5156
5157
5158
5159 </div>
5160
5161
5162
5163
5164 
5165     
5166     
5167     
5168     
5169      <p> </p>
5170
5171
5172
5173
5174 
5175     
5176     
5177     
5178     
5179      <p><span style="font-style: italic;">'ups-scheme'</span><br>
5180
5181
5182
5183
5184
5185      </p>
5186
5187
5188
5189
5190 
5191     
5192     
5193     
5194     
5195      <div style="margin-left: 40px;">The
5196upstream-spline scheme is
5197used
5198(see Mahrer and Pielke,
51991978: Mon. Wea. Rev., 106, 818-830). In opposite to the
5200Piascek-Williams scheme, this is characterized by much better numerical
5201features (less numerical diffusion, better preservation of flow
5202structures, e.g. vortices), but computationally it is much more
5203expensive. In
5204addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
5205= <span style="font-style: italic;">'</span><i>euler'</i>),
5206i.e. the
5207timestep accuracy is only of first order.
5208For this reason the advection of scalar variables (see <a href="#scalar_advec">scalar_advec</a>)
5209should then also be carried out with the upstream-spline scheme,
5210because otherwise the scalar variables would
5211be subject to large numerical diffusion due to the upstream
5212scheme.&nbsp; </div>
5213
5214
5215
5216
5217 
5218     
5219     
5220     
5221     
5222      <p style="margin-left: 40px;">Since
5223the cubic splines used tend
5224to overshoot under
5225certain circumstances, this effect must be adjusted by suitable
5226filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
5227      <a href="#long_filter_factor">long_filter_factor</a>,
5228      <a href="#ups_limit_pt">ups_limit_pt</a>, <a href="#ups_limit_u">ups_limit_u</a>, <a href="#ups_limit_v">ups_limit_v</a>, <a href="#ups_limit_w">ups_limit_w</a>).
5229This is always neccessary for runs with stable stratification,
5230even if this stratification appears only in parts of the model domain.<br>
5231
5232
5233
5234
5235
5236      </p>
5237
5238
5239
5240
5241 
5242     
5243     
5244     
5245     
5246      <div style="margin-left: 40px;">With stable
5247stratification the
5248upstream-spline scheme also
5249produces gravity waves with large amplitude, which must be
5250suitably damped (see <a href="chapter_4.2.html#rayleigh_damping_factor">rayleigh_damping_factor</a>).<br>
5251
5252
5253
5254
5255
5256      <br>
5257
5258
5259
5260
5261 <span style="font-weight: bold;">Important: </span>The&nbsp;
5262upstream-spline scheme is not implemented for humidity and passive
5263scalars (see&nbsp;<a href="#humidity">humidity</a>
5264and <a href="#passive_scalar">passive_scalar</a>)
5265and requires the use of a 2d-domain-decomposition. The last conditions
5266severely restricts code optimization on several machines leading to
5267very long execution times! The scheme is also not allowed for
5268non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
5269and <a href="#bc_ns">bc_ns</a>).</div>
5270
5271
5272
5273
5274 </td>
5275
5276
5277
5278
5279
5280    </tr>
5281
5282
5283
5284
5285 <tr>
5286
5287
5288
5289
5290 <td style="vertical-align: top;"><a name="netcdf_precision"></a><span style="font-weight: bold;">netcdf_precision</span><br>
5291
5292
5293
5294
5295
5296      </td>
5297
5298
5299
5300
5301 <td style="vertical-align: top;">C*20<br>
5302
5303
5304
5305
5306
5307(10)<br>
5308
5309
5310
5311
5312 </td>
5313
5314
5315
5316
5317 <td style="vertical-align: top;"><span style="font-style: italic;">single preci-</span><br style="font-style: italic;">
5318
5319
5320
5321
5322 <span style="font-style: italic;">sion for all</span><br style="font-style: italic;">
5323
5324
5325
5326
5327 <span style="font-style: italic;">output quan-</span><br style="font-style: italic;">
5328
5329
5330
5331
5332 <span style="font-style: italic;">tities</span><br>
5333
5334
5335
5336
5337 </td>
5338
5339
5340
5341
5342
5343      <td style="vertical-align: top;">Defines the accuracy of
5344the NetCDF output.<br>
5345
5346
5347
5348
5349 <br>
5350
5351
5352
5353
5354
5355By default, all NetCDF output data (see <a href="chapter_4.2.html#data_output_format">data_output_format</a>)
5356have single precision&nbsp; (4 byte) accuracy. Double precision (8
5357byte) can be choosen alternatively.<br>
5358
5359
5360
5361
5362
5363Accuracy for the different output data (cross sections, 3d-volume data,
5364spectra, etc.) can be set independently.<br>
5365
5366
5367
5368
5369 <span style="font-style: italic;">'&lt;out&gt;_NF90_REAL4'</span>
5370(single precision) or <span style="font-style: italic;">'&lt;out&gt;_NF90_REAL8'</span>
5371(double precision) are the two principally allowed values for <span style="font-weight: bold;">netcdf_precision</span>,
5372where the string <span style="font-style: italic;">'&lt;out&gt;'
5373      </span>can be chosen out of the following list:<br>
5374
5375
5376
5377
5378 <br>
5379
5380
5381
5382
5383
5384     
5385     
5386     
5387     
5388      <table style="text-align: left; width: 284px; height: 234px;" border="1" cellpadding="2" cellspacing="2">
5389
5390
5391
5392
5393 <tbody>
5394
5395
5396
5397
5398
5399          <tr>
5400
5401
5402
5403
5404 <td style="vertical-align: top;"><span style="font-style: italic;">'xy'</span><br>
5405
5406
5407
5408
5409 </td>
5410
5411
5412
5413
5414
5415            <td style="vertical-align: top;">horizontal cross section<br>
5416
5417
5418
5419
5420
5421            </td>
5422
5423
5424
5425
5426 </tr>
5427
5428
5429
5430
5431 <tr>
5432
5433
5434
5435
5436 <td style="vertical-align: top;"><span style="font-style: italic;">'xz'</span><br>
5437
5438
5439
5440
5441 </td>
5442
5443
5444
5445
5446
5447            <td style="vertical-align: top;">vertical (xz) cross
5448section<br>
5449
5450
5451
5452
5453 </td>
5454
5455
5456
5457
5458 </tr>
5459
5460
5461
5462
5463 <tr>
5464
5465
5466
5467
5468 <td style="vertical-align: top;"><span style="font-style: italic;">'yz'</span><br>
5469
5470
5471
5472
5473 </td>
5474
5475
5476
5477
5478
5479            <td style="vertical-align: top;">vertical (yz) cross
5480section<br>
5481
5482
5483
5484
5485 </td>
5486
5487
5488
5489
5490 </tr>
5491
5492
5493
5494
5495 <tr>
5496
5497
5498
5499
5500 <td style="vertical-align: top;"><span style="font-style: italic;">'2d'</span><br>
5501
5502
5503
5504
5505 </td>
5506
5507
5508
5509
5510
5511            <td style="vertical-align: top;">all cross sections<br>
5512
5513
5514
5515
5516
5517            </td>
5518
5519
5520
5521
5522 </tr>
5523
5524
5525
5526
5527 <tr>
5528
5529
5530
5531
5532 <td style="vertical-align: top;"><span style="font-style: italic;">'3d'</span><br>
5533
5534
5535
5536
5537 </td>
5538
5539
5540
5541
5542
5543            <td style="vertical-align: top;">volume data<br>
5544
5545
5546
5547
5548 </td>
5549
5550
5551
5552
5553
5554          </tr>
5555
5556
5557
5558
5559 <tr>
5560
5561
5562
5563
5564 <td style="vertical-align: top;"><span style="font-style: italic;">'pr'</span><br>
5565
5566
5567
5568
5569 </td>
5570
5571
5572
5573
5574
5575            <td style="vertical-align: top;">vertical profiles<br>
5576
5577
5578
5579
5580
5581            </td>
5582
5583
5584
5585
5586 </tr>
5587
5588
5589
5590
5591 <tr>
5592
5593
5594
5595
5596 <td style="vertical-align: top;"><span style="font-style: italic;">'ts'</span><br>
5597
5598
5599
5600
5601 </td>
5602
5603
5604
5605
5606
5607            <td style="vertical-align: top;">time series, particle
5608time series<br>
5609
5610
5611
5612
5613 </td>
5614
5615
5616
5617
5618 </tr>
5619
5620
5621
5622
5623 <tr>
5624
5625
5626
5627
5628 <td style="vertical-align: top;"><span style="font-style: italic;">'sp'</span><br>
5629
5630
5631
5632
5633 </td>
5634
5635
5636
5637
5638
5639            <td style="vertical-align: top;">spectra<br>
5640
5641
5642
5643
5644 </td>
5645
5646
5647
5648
5649
5650          </tr>
5651
5652
5653
5654
5655 <tr>
5656
5657
5658
5659
5660 <td style="vertical-align: top;"><span style="font-style: italic;">'prt'</span><br>
5661
5662
5663
5664
5665 </td>
5666
5667
5668
5669
5670
5671            <td style="vertical-align: top;">particles<br>
5672
5673
5674
5675
5676 </td>
5677
5678
5679
5680
5681
5682          </tr>
5683
5684
5685
5686
5687 <tr>
5688
5689
5690
5691
5692 <td style="vertical-align: top;"><span style="font-style: italic;">'all'</span><br>
5693
5694
5695
5696
5697 </td>
5698
5699
5700
5701
5702
5703            <td style="vertical-align: top;">all output quantities<br>
5704
5705
5706
5707
5708
5709            </td>
5710
5711
5712
5713
5714 </tr>
5715
5716
5717
5718
5719 
5720       
5721       
5722       
5723       
5724        </tbody> 
5725     
5726     
5727     
5728     
5729      </table>
5730
5731
5732
5733
5734 <br>
5735
5736
5737
5738
5739 <span style="font-weight: bold;">Example:</span><br>
5740
5741
5742
5743
5744
5745If all cross section data and the particle data shall be output in
5746double precision and all other quantities in single precision, then <span style="font-weight: bold;">netcdf_precision</span> = <span style="font-style: italic;">'2d_NF90_REAL8'</span>, <span style="font-style: italic;">'prt_NF90_REAL8'</span>
5747has to be assigned.<br>
5748
5749
5750
5751
5752 </td>
5753
5754
5755
5756
5757 </tr>
5758
5759
5760
5761
5762
5763    <tr>
5764
5765
5766
5767
5768 <td style="vertical-align: top;"> 
5769     
5770     
5771     
5772     
5773      <p><a name="npex"></a><b>npex</b></p>
5774
5775
5776
5777
5778 </td>
5779
5780
5781
5782
5783
5784      <td style="vertical-align: top;">I</td>
5785
5786
5787
5788
5789 <td style="vertical-align: top;"><br>
5790
5791
5792
5793
5794 </td>
5795
5796
5797
5798
5799 <td style="vertical-align: top;"> 
5800     
5801     
5802     
5803     
5804      <p>Number of processors
5805along x-direction of the virtual
5806processor
5807net.&nbsp; </p>
5808
5809
5810
5811
5812 
5813     
5814     
5815     
5816     
5817      <p>For parallel runs, the total
5818number of processors to be used
5819is given by
5820the <span style="font-weight: bold;">mrun</span>
5821option <a href="http://www.muk.uni-hannover.de/software/mrun_beschreibung.html#Opt-X">-X</a>.
5822By default, depending on the type of the parallel computer, PALM
5823generates a 1d processor
5824net (domain decomposition along x, <span style="font-weight: bold;">npey</span>
5825= <span style="font-style: italic;">1</span>) or a
58262d-net (this is
5827favored on machines with fast communication network). In case of a
58282d-net, it is tried to make it more or less square-shaped. If, for
5829example, 16 processors are assigned (-X 16), a 4 * 4 processor net is
5830generated (<span style="font-weight: bold;">npex</span>
5831= <span style="font-style: italic;">4</span>, <span style="font-weight: bold;">npey</span>
5832= <span style="font-style: italic;">4</span>).
5833This choice is optimal for square total domains (<a href="#nx">nx</a>
5834= <a href="#ny">ny</a>),
5835since then the number of ghost points at the lateral boundarys of
5836the subdomains is minimal. If <span style="font-weight: bold;">nx</span>
5837nd <span style="font-weight: bold;">ny</span>
5838differ extremely, the
5839processor net should be manually adjusted using adequate values for <span style="font-weight: bold;">npex</span> and <span style="font-weight: bold;">npey</span>.&nbsp; </p>
5840
5841
5842
5843
5844
5845     
5846     
5847     
5848     
5849      <p><b>Important:</b> The value of <span style="font-weight: bold;">npex</span> * <span style="font-weight: bold;">npey</span> must exactly
5850correspond to the
5851value assigned by the <span style="font-weight: bold;">mrun</span>-option
5852      <tt>-X</tt>.
5853Otherwise the model run will abort with a corresponding error
5854message.&nbsp; <br>
5855
5856
5857
5858
5859
5860Additionally, the specification of <span style="font-weight: bold;">npex</span>
5861and <span style="font-weight: bold;">npey</span>
5862may of course
5863override the default setting for the domain decomposition (1d or 2d)
5864which may have a significant (negative) effect on the code performance.
5865      </p>
5866
5867
5868
5869
5870 </td>
5871
5872
5873
5874
5875 </tr>
5876
5877
5878
5879
5880 <tr>
5881
5882
5883
5884
5885 <td style="vertical-align: top;"> 
5886     
5887     
5888     
5889     
5890      <p><a name="npey"></a><b>npey</b></p>
5891
5892
5893
5894
5895
5896      </td>
5897
5898
5899
5900
5901 <td style="vertical-align: top;">I</td>
5902
5903
5904
5905
5906
5907      <td style="vertical-align: top;"><br>
5908
5909
5910
5911
5912 </td>
5913
5914
5915
5916
5917 <td style="vertical-align: top;"> 
5918     
5919     
5920     
5921     
5922      <p>Number of processors
5923along y-direction of the virtual
5924processor
5925net.&nbsp; </p>
5926
5927
5928
5929
5930 
5931     
5932     
5933     
5934     
5935      <p>For further information see <a href="#npex">npex</a>.</p>
5936
5937
5938
5939
5940 </td>
5941
5942
5943
5944
5945 </tr>
5946
5947
5948
5949
5950
5951    <tr>
5952
5953
5954
5955
5956 <td style="vertical-align: top;"> 
5957     
5958     
5959     
5960     
5961      <p><a name="nsor_ini"></a><b>nsor_ini</b></p>
5962
5963
5964
5965
5966
5967      </td>
5968
5969
5970
5971
5972 <td style="vertical-align: top;">I</td>
5973
5974
5975
5976
5977
5978      <td style="vertical-align: top;"><i>100</i></td>
5979
5980
5981
5982
5983
5984      <td style="vertical-align: top;"> 
5985     
5986     
5987     
5988     
5989      <p>Initial number
5990of iterations with the SOR algorithm.&nbsp; </p>
5991
5992
5993
5994
5995 
5996     
5997     
5998     
5999     
6000      <p>This
6001parameter is only effective if the SOR algorithm was
6002selected as the pressure solver scheme (<a href="chapter_4.2.html#psolver">psolver</a>
6003= <span style="font-style: italic;">'sor'</span>)
6004and specifies the
6005number of initial iterations of the SOR
6006scheme (at t = 0). The number of subsequent iterations at the following
6007timesteps is determined
6008with the parameter <a href="#nsor">nsor</a>.
6009Usually <b>nsor</b> &lt; <b>nsor_ini</b>,
6010since in each case
6011subsequent calls to <a href="chapter_4.2.html#psolver">psolver</a>
6012use the solution of the previous call as initial value. Suitable
6013test runs should determine whether sufficient convergence of the
6014solution is obtained with the default value and if necessary the value
6015of <b>nsor_ini</b> should be changed.</p>
6016
6017
6018
6019
6020 </td>
6021
6022
6023
6024
6025
6026    </tr>
6027
6028
6029
6030
6031 <tr>
6032
6033
6034
6035
6036 <td style="vertical-align: top;">
6037     
6038     
6039     
6040     
6041      <p><a name="nx"></a><b>nx</b></p>
6042
6043
6044
6045
6046
6047      </td>
6048
6049
6050
6051
6052 <td style="vertical-align: top;">I</td>
6053
6054
6055
6056
6057
6058      <td style="vertical-align: top;"><br>
6059
6060
6061
6062
6063 </td>
6064
6065
6066
6067
6068 <td style="vertical-align: top;"> 
6069     
6070     
6071     
6072     
6073      <p>Number of grid
6074points in x-direction.&nbsp; </p>
6075
6076
6077
6078
6079 
6080     
6081     
6082     
6083     
6084      <p>A value for this
6085parameter must be assigned. Since the lower
6086array bound in PALM
6087starts with i = 0, the actual number of grid points is equal to <b>nx+1</b>.
6088In case of cyclic boundary conditions along x, the domain size is (<b>nx+1</b>)*
6089      <a href="#dx">dx</a>.</p>
6090
6091
6092
6093
6094 
6095     
6096     
6097     
6098     
6099      <p>For
6100parallel runs, in case of <a href="#grid_matching">grid_matching</a>
6101= <span style="font-style: italic;">'strict'</span>,
6102      <b>nx+1</b> must
6103be an integral multiple
6104of the processor numbers (see <a href="#npex">npex</a>
6105and <a href="#npey">npey</a>)
6106along x- as well as along y-direction (due to data
6107transposition restrictions).</p>
6108
6109
6110
6111
6112     
6113     
6114     
6115     
6116      <p>For <a href="chapter_3.8.html">coupled runs</a> this parameter must be&nbsp;equal in both parameter files <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2"><span style="font-family: mon;"></span>PARIN</font></a>
6117and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
6118
6119
6120
6121
6122 </td>
6123
6124
6125
6126
6127 </tr>
6128
6129
6130
6131
6132 <tr>
6133
6134
6135
6136
6137
6138      <td style="vertical-align: top;"> 
6139     
6140     
6141     
6142     
6143      <p><a name="ny"></a><b>ny</b></p>
6144
6145
6146
6147
6148
6149      </td>
6150
6151
6152
6153
6154 <td style="vertical-align: top;">I</td>
6155
6156
6157
6158
6159
6160      <td style="vertical-align: top;"><br>
6161
6162
6163
6164
6165 </td>
6166
6167
6168
6169
6170 <td style="vertical-align: top;"> 
6171     
6172     
6173     
6174     
6175      <p>Number of grid
6176points in y-direction.&nbsp; </p>
6177
6178
6179
6180
6181 
6182     
6183     
6184     
6185     
6186      <p>A value for this
6187parameter must be assigned. Since the lower
6188array bound in PALM starts with j = 0, the actual number of grid points
6189is equal to <b>ny+1</b>. In case of cyclic boundary
6190conditions along
6191y, the domain size is (<b>ny+1</b>) * <a href="#dy">dy</a>.</p>
6192
6193
6194
6195
6196
6197     
6198     
6199     
6200     
6201      <p>For parallel runs, in case of <a href="#grid_matching">grid_matching</a>
6202= <span style="font-style: italic;">'strict'</span>,
6203      <b>ny+1</b> must
6204be an integral multiple
6205of the processor numbers (see <a href="#npex">npex</a>
6206and <a href="#npey">npey</a>)&nbsp;
6207along y- as well as along x-direction (due to data
6208transposition restrictions).</p>
6209
6210
6211
6212
6213     
6214     
6215     
6216     
6217      <p>For <a href="chapter_3.8.html">coupled runs</a> this parameter must be&nbsp;equal in both parameter files <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2"><span style="font-family: mon;"></span>PARIN</font></a>
6218and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
6219
6220
6221
6222
6223 </td>
6224
6225
6226
6227
6228 </tr>
6229
6230
6231
6232
6233 <tr>
6234
6235
6236
6237
6238
6239      <td style="vertical-align: top;"> 
6240     
6241     
6242     
6243     
6244      <p><a name="nz"></a><b>nz</b></p>
6245
6246
6247
6248
6249
6250      </td>
6251
6252
6253
6254
6255 <td style="vertical-align: top;">I</td>
6256
6257
6258
6259
6260
6261      <td style="vertical-align: top;"><br>
6262
6263
6264
6265
6266 </td>
6267
6268
6269
6270
6271 <td style="vertical-align: top;"> 
6272     
6273     
6274     
6275     
6276      <p>Number of grid
6277points in z-direction.&nbsp; </p>
6278
6279
6280
6281
6282 
6283     
6284     
6285     
6286     
6287      <p>A value for this
6288parameter must be assigned. Since the lower
6289array bound in PALM
6290starts with k = 0 and since one additional grid point is added at the
6291top boundary (k = <b>nz+1</b>), the actual number of grid
6292points is <b>nz+2</b>.
6293However, the prognostic equations are only solved up to <b>nz</b>
6294(u,
6295v)
6296or up to <b>nz-1</b> (w, scalar quantities). The top
6297boundary for u
6298and v is at k = <b>nz+1</b> (u, v) while at k = <b>nz</b>
6299for all
6300other quantities.&nbsp; </p>
6301
6302
6303
6304
6305 
6306     
6307     
6308     
6309     
6310      <p>For parallel
6311runs,&nbsp; in case of <a href="#grid_matching">grid_matching</a>
6312= <span style="font-style: italic;">'strict'</span>,
6313      <b>nz</b> must
6314be an integral multiple of
6315the number of processors in x-direction (due to data transposition
6316restrictions).</p>
6317
6318
6319
6320
6321 </td>
6322
6323
6324
6325
6326 </tr>
6327
6328
6329
6330
6331 <tr>
6332
6333
6334
6335
6336      <td style="vertical-align: top;"><a name="ocean"></a><span style="font-weight: bold;">ocean</span></td>
6337
6338
6339
6340
6341      <td style="vertical-align: top;">L</td>
6342
6343
6344
6345
6346      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
6347
6348
6349
6350
6351      <td style="vertical-align: top;">Parameter to switch on&nbsp;ocean runs.<br>
6352
6353
6354
6355
6356      <br>
6357
6358
6359
6360
6361By default PALM is configured to simulate&nbsp;atmospheric flows. However, starting from version 3.3, <span style="font-weight: bold;">ocean</span> = <span style="font-style: italic;">.T.</span> allows&nbsp;simulation of ocean turbulent flows. Setting this switch has several effects:<br>
6362
6363
6364
6365
6366      <br>
6367
6368
6369
6370
6371     
6372     
6373     
6374     
6375      <ul>
6376
6377
6378
6379
6380        <li>An additional prognostic equation for salinity is solved.</li>
6381
6382
6383
6384
6385        <li>Potential temperature in buoyancy and stability-related terms is replaced by potential density.</li>
6386
6387
6388
6389
6390        <li>Potential
6391density is calculated from the equation of state for seawater after
6392each timestep, using the algorithm proposed by Jackett et al. (2006, J.
6393Atmos. Oceanic Technol., <span style="font-weight: bold;">23</span>, 1709-1728).<br>
6394
6395
6396
6397
6398So far, only the initial hydrostatic pressure is entered into this equation.</li>
6399
6400
6401
6402
6403        <li>z=0 (sea surface) is assumed at the model top (vertical grid index <span style="font-family: Courier New,Courier,monospace;">k=nzt</span> on the w-grid), with negative values of z indicating the depth.</li>
6404
6405
6406
6407
6408        <li>Initial profiles are constructed (e.g. from <a href="#pt_vertical_gradient">pt_vertical_gradient</a> / <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>) starting from the sea surface, using surface values&nbsp;given by <a href="#pt_surface">pt_surface</a>, <a href="#sa_surface">sa_surface</a>, <a href="#ug_surface">ug_surface</a>, and <a href="#vg_surface">vg_surface</a>.</li>
6409
6410
6411
6412
6413        <li>Zero salinity flux is used as default boundary condition at the bottom of the sea.</li>
6414
6415
6416
6417
6418        <li>If switched on, random perturbations are by default imposed to the upper model domain from zu(nzt*2/3) to zu(nzt-3).</li>
6419
6420
6421
6422
6423     
6424     
6425     
6426     
6427      </ul>
6428
6429
6430
6431
6432      <br>
6433
6434
6435
6436
6437Relevant parameters to be exclusively used for steering ocean runs are <a href="#bc_sa_t">bc_sa_t</a>, <a href="#bottom_salinityflux">bottom_salinityflux</a>, <a href="#sa_surface">sa_surface</a>, <a href="#sa_vertical_gradient">sa_vertical_gradient</a>, <a href="#sa_vertical_gradient_level">sa_vertical_gradient_level</a>, and <a href="#top_salinityflux">top_salinityflux</a>.<br>
6438
6439
6440
6441
6442      <br>
6443
6444
6445
6446
6447Section <a href="chapter_4.2.2.html">4.4.2</a> gives an example for appropriate settings of these and other parameters neccessary for ocean runs.<br>
6448
6449
6450
6451
6452      <br>
6453
6454
6455
6456
6457      <span style="font-weight: bold;">ocean</span> = <span style="font-style: italic;">.T.</span> does not allow settings of <a href="#timestep_scheme">timestep_scheme</a> = <span style="font-style: italic;">'leapfrog'</span> or <span style="font-style: italic;">'leapfrog+euler'</span> as well as <a href="#scalar_advec">scalar_advec</a> = <span style="font-style: italic;">'ups-scheme'</span>.<span style="font-weight: bold;"></span><br>
6458
6459      </td>
6460
6461
6462
6463
6464    </tr>
6465
6466
6467
6468
6469    <tr>
6470
6471
6472
6473
6474 <td style="vertical-align: top;"> 
6475     
6476     
6477     
6478     
6479      <p><a name="omega"></a><b>omega</b></p>
6480
6481
6482
6483
6484
6485      </td>
6486
6487
6488
6489
6490 <td style="vertical-align: top;">R</td>
6491
6492
6493
6494
6495
6496      <td style="vertical-align: top;"><i>7.29212E-5</i></td>
6497
6498
6499
6500
6501
6502      <td style="vertical-align: top;"> 
6503     
6504     
6505     
6506     
6507      <p>Angular
6508velocity of the rotating system (in rad s<sup>-1</sup>).&nbsp;
6509      </p>
6510
6511
6512
6513
6514 
6515     
6516     
6517     
6518     
6519      <p>The angular velocity of the earth is set by
6520default. The
6521values
6522of the Coriolis parameters are calculated as:&nbsp; </p>
6523
6524
6525
6526
6527 
6528     
6529     
6530     
6531     
6532      <ul>
6533
6534
6535
6536
6537
6538       
6539       
6540       
6541       
6542        <p>f = 2.0 * <b>omega</b> * sin(<a href="#phi">phi</a>)&nbsp;
6543        <br>
6544
6545
6546
6547
6548f* = 2.0 * <b>omega</b> * cos(<a href="#phi">phi</a>)</p>
6549
6550
6551
6552
6553
6554     
6555     
6556     
6557     
6558      </ul>
6559
6560
6561
6562
6563 </td>
6564
6565
6566
6567
6568 </tr>
6569
6570
6571
6572
6573 <tr>
6574
6575
6576
6577
6578 <td style="vertical-align: top;"> 
6579     
6580     
6581     
6582     
6583      <p><a name="outflow_damping_width"></a><b>outflow_damping_width</b></p>
6584
6585
6586
6587
6588
6589      </td>
6590
6591
6592
6593
6594 <td style="vertical-align: top;">I</td>
6595
6596
6597
6598
6599
6600      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(20,
6601nx/2</span> or <span style="font-style: italic;">ny/2)</span></td>
6602
6603
6604
6605
6606
6607      <td style="vertical-align: top;">Width of
6608the damping range in the vicinity of the outflow (gridpoints).<br>
6609
6610
6611
6612
6613
6614      <br>
6615
6616
6617
6618
6619
6620When using non-cyclic lateral boundaries (see <a href="chapter_4.1.html#bc_lr">bc_lr</a>
6621or <a href="chapter_4.1.html#bc_ns">bc_ns</a>),
6622a smoothing has to be applied to the
6623velocity field in the vicinity of the outflow in order to suppress any
6624reflections of outgoing disturbances. This parameter controlls the
6625horizontal range to which the smoothing is applied. The range is given
6626in gridpoints counted from the respective outflow boundary. For further
6627details about the smoothing see parameter <a href="chapter_4.1.html#km_damp_max">km_damp_max</a>,
6628which defines the magnitude of the damping.</td>
6629
6630
6631
6632
6633 </tr>
6634
6635
6636
6637
6638
6639    <tr>
6640
6641
6642
6643
6644 <td style="vertical-align: top;"> 
6645     
6646     
6647     
6648     
6649      <p><a name="overshoot_limit_e"></a><b>overshoot_limit_e</b></p>
6650
6651
6652
6653
6654
6655      </td>
6656
6657
6658
6659
6660 <td style="vertical-align: top;">R</td>
6661
6662
6663
6664
6665
6666      <td style="vertical-align: top;"><i>0.0</i></td>
6667
6668
6669
6670
6671
6672      <td style="vertical-align: top;"> 
6673     
6674     
6675     
6676     
6677      <p>Allowed limit
6678for the overshooting of subgrid-scale TKE in
6679case that the upstream-spline scheme is switched on (in m<sup>2</sup>/s<sup>2</sup>).&nbsp;
6680      </p>
6681
6682
6683
6684
6685 
6686     
6687     
6688     
6689     
6690      <p>By deafult, if cut-off of overshoots is switched
6691on for the
6692upstream-spline scheme (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>),
6693no overshoots are permitted at all. If <b>overshoot_limit_e</b>
6694is given a non-zero value, overshoots with the respective
6695amplitude (both upward and downward) are allowed.&nbsp; </p>
6696
6697
6698
6699
6700
6701     
6702     
6703     
6704     
6705      <p>Only positive values are allowed for <b>overshoot_limit_e</b>.</p>
6706
6707
6708
6709
6710
6711      </td>
6712
6713
6714
6715
6716 </tr>
6717
6718
6719
6720
6721 <tr>
6722
6723
6724
6725
6726 <td style="vertical-align: top;"> 
6727     
6728     
6729     
6730     
6731      <p><a name="overshoot_limit_pt"></a><b>overshoot_limit_pt</b></p>
6732
6733
6734
6735
6736
6737      </td>
6738
6739
6740
6741
6742 <td style="vertical-align: top;">R</td>
6743
6744
6745
6746
6747
6748      <td style="vertical-align: top;"><i>0.0</i></td>
6749
6750
6751
6752
6753
6754      <td style="vertical-align: top;"> 
6755     
6756     
6757     
6758     
6759      <p>Allowed limit
6760for the overshooting of potential temperature in
6761case that the upstream-spline scheme is switched on (in K).&nbsp; </p>
6762
6763
6764
6765
6766
6767     
6768     
6769     
6770     
6771      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6772      </p>
6773
6774
6775
6776
6777 
6778     
6779     
6780     
6781     
6782      <p>Only positive values are allowed for <b>overshoot_limit_pt</b>.</p>
6783
6784
6785
6786
6787
6788      </td>
6789
6790
6791
6792
6793 </tr>
6794
6795
6796
6797
6798 <tr>
6799
6800
6801
6802
6803 <td style="vertical-align: top;"> 
6804     
6805     
6806     
6807     
6808      <p><a name="overshoot_limit_u"></a><b>overshoot_limit_u</b></p>
6809
6810
6811
6812
6813
6814      </td>
6815
6816
6817
6818
6819 <td style="vertical-align: top;">R</td>
6820
6821
6822
6823
6824
6825      <td style="vertical-align: top;"><i>0.0</i></td>
6826
6827
6828
6829
6830
6831      <td style="vertical-align: top;">Allowed limit for the
6832overshooting of
6833the u-component of velocity in case that the upstream-spline scheme is
6834switched on (in m/s).
6835     
6836     
6837     
6838     
6839      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6840      </p>
6841
6842
6843
6844
6845 
6846     
6847     
6848     
6849     
6850      <p>Only positive values are allowed for <b>overshoot_limit_u</b>.</p>
6851
6852
6853
6854
6855
6856      </td>
6857
6858
6859
6860
6861 </tr>
6862
6863
6864
6865
6866 <tr>
6867
6868
6869
6870
6871 <td style="vertical-align: top;"> 
6872     
6873     
6874     
6875     
6876      <p><a name="overshoot_limit_v"></a><b>overshoot_limit_v</b></p>
6877
6878
6879
6880
6881
6882      </td>
6883
6884
6885
6886
6887 <td style="vertical-align: top;">R</td>
6888
6889
6890
6891
6892
6893      <td style="vertical-align: top;"><i>0.0</i></td>
6894
6895
6896
6897
6898
6899      <td style="vertical-align: top;"> 
6900     
6901     
6902     
6903     
6904      <p>Allowed limit
6905for the overshooting of the v-component of
6906velocity in case that the upstream-spline scheme is switched on
6907(in m/s).&nbsp; </p>
6908
6909
6910
6911
6912 
6913     
6914     
6915     
6916     
6917      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6918      </p>
6919
6920
6921
6922
6923 
6924     
6925     
6926     
6927     
6928      <p>Only positive values are allowed for <b>overshoot_limit_v</b>.</p>
6929
6930
6931
6932
6933
6934      </td>
6935
6936
6937
6938
6939 </tr>
6940
6941
6942
6943
6944 <tr>
6945
6946
6947
6948
6949 <td style="vertical-align: top;"> 
6950     
6951     
6952     
6953     
6954      <p><a name="overshoot_limit_w"></a><b>overshoot_limit_w</b></p>
6955
6956
6957
6958
6959
6960      </td>
6961
6962
6963
6964
6965 <td style="vertical-align: top;">R</td>
6966
6967
6968
6969
6970
6971      <td style="vertical-align: top;"><i>0.0</i></td>
6972
6973
6974
6975
6976
6977      <td style="vertical-align: top;"> 
6978     
6979     
6980     
6981     
6982      <p>Allowed limit
6983for the overshooting of the w-component of
6984velocity in case that the upstream-spline scheme is switched on
6985(in m/s).&nbsp; </p>
6986
6987
6988
6989
6990 
6991     
6992     
6993     
6994     
6995      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6996      </p>
6997
6998
6999
7000
7001 
7002     
7003     
7004     
7005     
7006      <p>Only positive values are permitted for <b>overshoot_limit_w</b>.</p>
7007
7008
7009
7010
7011
7012      </td>
7013
7014
7015
7016
7017 </tr>
7018
7019
7020
7021
7022 <tr>
7023
7024
7025
7026
7027 <td style="vertical-align: top;"> 
7028     
7029     
7030     
7031     
7032      <p><a name="passive_scalar"></a><b>passive_scalar</b></p>
7033
7034
7035
7036
7037
7038      </td>
7039
7040
7041
7042
7043 <td style="vertical-align: top;">L</td>
7044
7045
7046
7047
7048
7049      <td style="vertical-align: top;"><i>.F.</i></td>
7050
7051
7052
7053
7054
7055      <td style="vertical-align: top;"> 
7056     
7057     
7058     
7059     
7060      <p>Parameter to
7061switch on the prognostic equation for a passive
7062scalar. <br>
7063
7064
7065
7066
7067 </p>
7068
7069
7070
7071
7072 
7073     
7074     
7075     
7076     
7077      <p>The initial vertical profile
7078of s can be set via parameters <a href="#s_surface">s_surface</a>,
7079      <a href="#s_vertical_gradient">s_vertical_gradient</a>
7080and&nbsp; <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
7081Boundary conditions can be set via <a href="#s_surface_initial_change">s_surface_initial_change</a>
7082and <a href="#surface_scalarflux">surface_scalarflux</a>.&nbsp;
7083      </p>
7084
7085
7086
7087
7088 
7089     
7090     
7091     
7092     
7093      <p><b>Note:</b> <br>
7094
7095
7096
7097
7098
7099With <span style="font-weight: bold;">passive_scalar</span>
7100switched
7101on, the simultaneous use of humidity (see&nbsp;<a href="#humidity">humidity</a>)
7102is impossible.</p>
7103
7104
7105
7106
7107 </td>
7108
7109
7110
7111
7112 </tr>
7113
7114
7115
7116
7117 <tr><td><a name="pch_index"></a><span style="font-weight: bold;">pch_index</span></td><td>I</td><td><span style="font-style: italic;">0</span></td><td>Grid point index (scalar) of the upper boundary of the plant canopy layer.<br><br>Above <span style="font-weight: bold;">pch_index</span> the arrays of leaf area density and drag_coeffient are automatically set to zero in case of <a href="#plant_canopy">plant_canopy</a> = .T.. Up to <span style="font-weight: bold;">pch_index</span> a leaf area density profile can be prescribed by using the parameters <a href="#lad_surface">lad_surface</a>, <a href="#lad_vertical_gradient">lad_vertical_gradient</a> and <a href="#lad_vertical_gradient_level">lad_vertical_gradient_level</a>.</td></tr><tr>
7118
7119
7120
7121
7122 <td style="vertical-align: top;"> 
7123     
7124     
7125     
7126     
7127      <p><a name="phi"></a><b>phi</b></p>
7128
7129
7130
7131
7132
7133      </td>
7134
7135
7136
7137
7138 <td style="vertical-align: top;">R</td>
7139
7140
7141
7142
7143
7144      <td style="vertical-align: top;"><i>55.0</i></td>
7145
7146
7147
7148
7149
7150      <td style="vertical-align: top;"> 
7151     
7152     
7153     
7154     
7155      <p>Geographical
7156latitude (in degrees).&nbsp; </p>
7157
7158
7159
7160
7161 
7162     
7163     
7164     
7165     
7166      <p>The value of
7167this parameter determines the value of the
7168Coriolis parameters f and f*, provided that the angular velocity (see <a href="#omega">omega</a>)
7169is non-zero.</p>
7170
7171
7172
7173
7174 </td>
7175
7176
7177
7178
7179 </tr>
7180
7181
7182
7183
7184 <tr><td><a name="plant_canopy"></a><span style="font-weight: bold;">plant_canopy</span></td><td>L</td><td><span style="font-style: italic;">.F.</span></td><td>Switch for the plant_canopy_model.<br><br>If <span style="font-weight: bold;">plant_canopy</span> is set <span style="font-style: italic;">.T.</span>, the plant canopy model of Watanabe (2004, BLM 112, 307-341) is used. <br>The
7185impact of a plant canopy on a turbulent flow is considered by an
7186additional drag term in the momentum equations and an additional sink
7187term in the prognostic equation for the subgrid-scale TKE. These
7188additional terms are dependent on the leaf drag coefficient (see <a href="#drag_coefficient">drag_coefficient</a>) and the leaf area density (see <a href="#lad_surface">lad_surface</a>, <a href="#lad_vertical_gradient">lad_vertical_gradient</a>, <a href="#lad_vertical_gradient_level">lad_vertical_gradient_level</a>). <br>By default, a horizontally homogeneous plant canopy is prescribed, if&nbsp; <span style="font-weight: bold;">plant_canopy</span> is set <span style="font-style: italic;">.T.</span>. However, the user can define other types of plant canopies (see <a href="#canopy_mode">canopy_mode</a>).<br><br><span style="font-weight: bold;">plant_canopy</span> = <span style="font-style: italic;">.T. </span>is only allowed together with a non-zero <a href="#drag_coefficient">drag_coefficient</a>.</td></tr><tr>
7189
7190
7191
7192
7193 <td style="vertical-align: top;"> 
7194     
7195     
7196     
7197     
7198      <p><a name="prandtl_layer"></a><b>prandtl_layer</b></p>
7199
7200
7201
7202
7203
7204      </td>
7205
7206
7207
7208
7209 <td style="vertical-align: top;">L</td>
7210
7211
7212
7213
7214
7215      <td style="vertical-align: top;"><i>.T.</i></td>
7216
7217
7218
7219
7220
7221      <td style="vertical-align: top;"> 
7222     
7223     
7224     
7225     
7226      <p>Parameter to
7227switch on a Prandtl layer.&nbsp; </p>
7228
7229
7230
7231
7232 
7233     
7234     
7235     
7236     
7237      <p>By default,
7238a Prandtl layer is switched on at the bottom
7239boundary between z = 0 and z = 0.5 * <a href="#dz">dz</a>
7240(the first computational grid point above ground for u, v and the
7241scalar quantities).
7242In this case, at the bottom boundary, free-slip conditions for u and v
7243(see <a href="#bc_uv_b">bc_uv_b</a>)
7244are not allowed. Likewise, laminar
7245simulations with constant eddy diffusivities (<a href="#km_constant">km_constant</a>)
7246are forbidden.&nbsp; </p>
7247
7248
7249
7250
7251 
7252     
7253     
7254     
7255     
7256      <p>With Prandtl-layer
7257switched off, the TKE boundary condition <a href="#bc_e_b">bc_e_b</a>
7258= '<i>(u*)**2+neumann'</i> must not be used and is
7259automatically
7260changed to <i>'neumann'</i> if necessary.&nbsp; Also,
7261the pressure
7262boundary condition <a href="#bc_p_b">bc_p_b</a>
7263= <i>'neumann+inhomo'</i>&nbsp; is not allowed. </p>
7264
7265
7266
7267
7268
7269     
7270     
7271     
7272     
7273      <p>The roughness length is declared via the parameter <a href="#roughness_length">roughness_length</a>.</p>
7274
7275
7276
7277
7278
7279      </td>
7280
7281
7282
7283
7284 </tr>
7285
7286
7287
7288
7289 <tr>
7290
7291
7292
7293
7294 <td style="vertical-align: top;"> 
7295     
7296     
7297     
7298     
7299      <p><a name="precipitation"></a><b>precipitation</b></p>
7300
7301
7302
7303
7304
7305      </td>
7306
7307
7308
7309
7310 <td style="vertical-align: top;">L</td>
7311
7312
7313
7314
7315
7316      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
7317
7318
7319
7320
7321 <td style="vertical-align: top;"> 
7322     
7323     
7324     
7325     
7326      <p>Parameter to switch
7327on the precipitation scheme.<br>
7328
7329
7330
7331
7332 </p>
7333
7334
7335
7336
7337 
7338     
7339     
7340     
7341     
7342      <p>For
7343precipitation processes PALM uses a simplified Kessler
7344scheme. This scheme only considers the
7345so-called autoconversion, that means the generation of rain water by
7346coagulation of cloud drops among themselves. Precipitation begins and
7347is immediately removed from the flow as soon as the liquid water
7348content exceeds the critical value of 0.5 g/kg.</p>
7349
7350
7351
7352
7353     
7354     
7355     
7356     
7357      <p>The precipitation rate and amount can be output by assigning the runtime parameter <a href="chapter_4.2.html#data_output">data_output</a> = <span style="font-style: italic;">'prr*'</span> or <span style="font-style: italic;">'pra*'</span>, respectively. The time interval on which the precipitation amount is defined can be controlled via runtime parameter <a href="chapter_4.2.html#precipitation_amount_interval">precipitation_amount_interval</a>.</p>
7358
7359
7360
7361
7362 </td>
7363
7364
7365
7366
7367 </tr>
7368
7369
7370
7371
7372
7373    <tr>
7374
7375
7376
7377
7378      <td style="vertical-align: top;"><a name="pt_reference"></a><span style="font-weight: bold;">pt_reference</span></td>
7379
7380
7381
7382
7383      <td style="vertical-align: top;">R</td>
7384
7385
7386
7387
7388      <td style="vertical-align: top;"><span style="font-style: italic;">use horizontal average as
7389refrence</span></td>
7390
7391
7392
7393
7394      <td style="vertical-align: top;">Reference
7395temperature to be used in all buoyancy terms (in K).<br>
7396
7397
7398
7399
7400      <br>
7401
7402
7403
7404
7405By
7406default, the instantaneous horizontal average over the total model
7407domain is used.<br>
7408
7409
7410
7411
7412      <br>
7413
7414
7415
7416
7417      <span style="font-weight: bold;">Attention:</span><br>
7418
7419
7420
7421
7422In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>), always a reference temperature is used in the buoyancy terms with a default value of <span style="font-weight: bold;">pt_reference</span> = <a href="#pt_surface">pt_surface</a>.</td>
7423
7424
7425
7426
7427    </tr>
7428
7429
7430
7431
7432    <tr>
7433
7434
7435
7436
7437 <td style="vertical-align: top;"> 
7438     
7439     
7440     
7441     
7442      <p><a name="pt_surface"></a><b>pt_surface</b></p>
7443
7444
7445
7446
7447
7448      </td>
7449
7450
7451
7452
7453 <td style="vertical-align: top;">R</td>
7454
7455
7456
7457
7458
7459      <td style="vertical-align: top;"><i>300.0</i></td>
7460
7461
7462
7463
7464
7465      <td style="vertical-align: top;"> 
7466     
7467     
7468     
7469     
7470      <p>Surface
7471potential temperature (in K).&nbsp; </p>
7472
7473
7474
7475
7476 
7477     
7478     
7479     
7480     
7481      <p>This
7482parameter assigns the value of the potential temperature
7483      <span style="font-weight: bold;">pt</span> at the surface (k=0)<b>.</b> Starting from this value,
7484the
7485initial vertical temperature profile is constructed with <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7486and <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level
7487      </a>.
7488This profile is also used for the 1d-model as a stationary profile.</p>
7489
7490
7491
7492
7493     
7494     
7495     
7496     
7497      <p><span style="font-weight: bold;">Attention:</span><br>
7498
7499
7500
7501
7502In case of ocean runs (see <a href="#ocean">ocean</a>),
7503this parameter gives the temperature value at the sea surface, which is
7504at k=nzt. The profile is then constructed from the surface down to the
7505bottom of the model.</p>
7506
7507
7508
7509
7510
7511      </td>
7512
7513
7514
7515
7516 </tr>
7517
7518
7519
7520
7521 <tr>
7522
7523
7524
7525
7526 <td style="vertical-align: top;"> 
7527     
7528     
7529     
7530     
7531      <p><a name="pt_surface_initial_change"></a><b>pt_surface_initial</b>
7532      <br>
7533
7534
7535
7536
7537 <b>_change</b></p>
7538
7539
7540
7541
7542 </td>
7543
7544
7545
7546
7547 <td style="vertical-align: top;">R</td>
7548
7549
7550
7551
7552 <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
7553
7554
7555
7556
7557 </td>
7558
7559
7560
7561
7562
7563      <td style="vertical-align: top;"> 
7564     
7565     
7566     
7567     
7568      <p>Change in
7569surface temperature to be made at the beginning of
7570the 3d run
7571(in K).&nbsp; </p>
7572
7573
7574
7575
7576 
7577     
7578     
7579     
7580     
7581      <p>If <b>pt_surface_initial_change</b>
7582is set to a non-zero
7583value, the near surface sensible heat flux is not allowed to be given
7584simultaneously (see <a href="#surface_heatflux">surface_heatflux</a>).</p>
7585
7586
7587
7588
7589
7590      </td>
7591
7592
7593
7594
7595 </tr>
7596
7597
7598
7599
7600 <tr>
7601
7602
7603
7604
7605 <td style="vertical-align: top;"> 
7606     
7607     
7608     
7609     
7610      <p><a name="pt_vertical_gradient"></a><b>pt_vertical_gradient</b></p>
7611
7612
7613
7614
7615
7616      </td>
7617
7618
7619
7620
7621 <td style="vertical-align: top;">R (10)</td>
7622
7623
7624
7625
7626
7627      <td style="vertical-align: top;"><i>10 * 0.0</i></td>
7628
7629
7630
7631
7632
7633      <td style="vertical-align: top;"> 
7634     
7635     
7636     
7637     
7638      <p>Temperature
7639gradient(s) of the initial temperature profile (in
7640K
7641/ 100 m).&nbsp; </p>
7642
7643
7644
7645
7646 
7647     
7648     
7649     
7650     
7651      <p>This temperature gradient
7652holds starting from the height&nbsp;
7653level defined by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>
7654(precisely: for all uv levels k where zu(k) &gt;
7655pt_vertical_gradient_level,
7656pt_init(k) is set: pt_init(k) = pt_init(k-1) + dzu(k) * <b>pt_vertical_gradient</b>)
7657up to the top boundary or up to the next height level defined
7658by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>.
7659A total of 10 different gradients for 11 height intervals (10 intervals
7660if <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>(1)
7661= <i>0.0</i>) can be assigned. The surface temperature is
7662assigned via <a href="#pt_surface">pt_surface</a>.&nbsp;
7663      </p>
7664
7665
7666
7667
7668 
7669     
7670     
7671     
7672     
7673      <p>Example:&nbsp; </p>
7674
7675
7676
7677
7678 
7679     
7680     
7681     
7682     
7683      <ul>
7684
7685
7686
7687
7688 
7689       
7690       
7691       
7692       
7693        <p><b>pt_vertical_gradient</b>
7694= <i>1.0</i>, <i>0.5</i>,&nbsp; <br>
7695
7696
7697
7698
7699
7700        <b>pt_vertical_gradient_level</b> = <i>500.0</i>,
7701        <i>1000.0</i>,</p>
7702
7703
7704
7705
7706 
7707     
7708     
7709     
7710     
7711      </ul>
7712
7713
7714
7715
7716 
7717     
7718     
7719     
7720     
7721      <p>That
7722defines the temperature profile to be neutrally
7723stratified
7724up to z = 500.0 m with a temperature given by <a href="#pt_surface">pt_surface</a>.
7725For 500.0 m &lt; z &lt;= 1000.0 m the temperature gradient is
77261.0 K /
7727100 m and for z &gt; 1000.0 m up to the top boundary it is
77280.5 K / 100 m (it is assumed that the assigned height levels correspond
7729with uv levels).</p>
7730
7731
7732
7733
7734     
7735     
7736     
7737     
7738      <p><span style="font-weight: bold;">Attention:</span><br>
7739
7740
7741
7742
7743In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>),
7744the profile is constructed like described above, but starting from the
7745sea surface (k=nzt) down to the bottom boundary of the model. Height
7746levels have then to be given as negative values, e.g. <span style="font-weight: bold;">pt_vertical_gradient_level</span> = <span style="font-style: italic;">-500.0</span>, <span style="font-style: italic;">-1000.0</span>.</p>
7747
7748
7749
7750
7751 </td>
7752
7753
7754
7755
7756 </tr>
7757
7758
7759
7760
7761 <tr>
7762
7763
7764
7765
7766 <td style="vertical-align: top;"> 
7767     
7768     
7769     
7770     
7771      <p><a name="pt_vertical_gradient_level"></a><b>pt_vertical_gradient</b>
7772      <br>
7773
7774
7775
7776
7777 <b>_level</b></p>
7778
7779
7780
7781
7782 </td>
7783
7784
7785
7786
7787 <td style="vertical-align: top;">R (10)</td>
7788
7789
7790
7791
7792 <td style="vertical-align: top;"> 
7793     
7794     
7795     
7796     
7797      <p><i>10 *</i>&nbsp;
7798      <span style="font-style: italic;">0.0</span><br>
7799
7800
7801
7802
7803
7804      </p>
7805
7806
7807
7808
7809 </td>
7810
7811
7812
7813
7814 <td style="vertical-align: top;">
7815     
7816     
7817     
7818     
7819      <p>Height level from which on the temperature gradient defined by
7820      <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7821is effective (in m).&nbsp; </p>
7822
7823
7824
7825
7826 
7827     
7828     
7829     
7830     
7831      <p>The height levels have to be assigned in ascending order. The
7832default values result in a neutral stratification regardless of the
7833values of <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7834(unless the top boundary of the model is higher than 100000.0 m).
7835For the piecewise construction of temperature profiles see <a href="#pt_vertical_gradient">pt_vertical_gradient</a>.</p>
7836
7837
7838
7839
7840      <span style="font-weight: bold;">Attention:</span><br>
7841
7842
7843
7844
7845In case of ocean runs&nbsp;(see <a href="chapter_4.1.html#ocean">ocean</a>), the (negative) height levels have to be assigned in descending order.
7846      </td>
7847
7848
7849
7850
7851 </tr>
7852
7853
7854
7855
7856 <tr>
7857
7858
7859
7860
7861 <td style="vertical-align: top;"> 
7862     
7863     
7864     
7865     
7866      <p><a name="q_surface"></a><b>q_surface</b></p>
7867
7868
7869
7870
7871
7872      </td>
7873
7874
7875
7876
7877 <td style="vertical-align: top;">R</td>
7878
7879
7880
7881
7882
7883      <td style="vertical-align: top;"><i>0.0</i></td>
7884
7885
7886
7887
7888
7889      <td style="vertical-align: top;"> 
7890     
7891     
7892     
7893     
7894      <p>Surface
7895specific humidity / total water content (kg/kg).&nbsp; </p>
7896
7897
7898
7899
7900 
7901     
7902     
7903     
7904     
7905      <p>This
7906parameter assigns the value of the specific humidity q at
7907the surface (k=0).&nbsp; Starting from this value, the initial
7908humidity
7909profile is constructed with&nbsp; <a href="#q_vertical_gradient">q_vertical_gradient</a>
7910and <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
7911This profile is also used for the 1d-model as a stationary profile.</p>
7912
7913
7914
7915
7916
7917      </td>
7918
7919
7920
7921
7922 </tr>
7923
7924
7925
7926
7927 <tr>
7928
7929
7930
7931
7932 <td style="vertical-align: top;"> 
7933     
7934     
7935     
7936     
7937      <p><a name="q_surface_initial_change"></a><b>q_surface_initial</b>
7938      <br>
7939
7940
7941
7942
7943 <b>_change</b></p>
7944
7945
7946
7947
7948 </td>
7949
7950
7951
7952
7953 <td style="vertical-align: top;">R<br>
7954
7955
7956
7957
7958 </td>
7959
7960
7961
7962
7963 <td style="vertical-align: top;"><i>0.0</i></td>
7964
7965
7966
7967
7968
7969      <td style="vertical-align: top;"> 
7970     
7971     
7972     
7973     
7974      <p>Change in
7975surface specific humidity / total water content to
7976be made at the beginning
7977of the 3d run (kg/kg).&nbsp; </p>
7978
7979
7980
7981
7982 
7983     
7984     
7985     
7986     
7987      <p>If <b>q_surface_initial_change</b><i>
7988      </i>is set to a
7989non-zero value the
7990near surface latent heat flux (water flux) is not allowed to be given
7991simultaneously (see <a href="#surface_waterflux">surface_waterflux</a>).</p>
7992
7993
7994
7995
7996
7997      </td>
7998
7999
8000
8001
8002 </tr>
8003
8004
8005
8006
8007 <tr>
8008
8009
8010
8011
8012 <td style="vertical-align: top;"> 
8013     
8014     
8015     
8016     
8017      <p><a name="q_vertical_gradient"></a><b>q_vertical_gradient</b></p>
8018
8019
8020
8021
8022
8023      </td>
8024
8025
8026
8027
8028 <td style="vertical-align: top;">R (10)</td>
8029
8030
8031
8032
8033
8034      <td style="vertical-align: top;"><i>10 * 0.0</i></td>
8035
8036
8037
8038
8039
8040      <td style="vertical-align: top;"> 
8041     
8042     
8043     
8044     
8045      <p>Humidity
8046gradient(s) of the initial humidity profile
8047(in 1/100 m).&nbsp; </p>
8048
8049
8050
8051
8052 
8053     
8054     
8055     
8056     
8057      <p>This humidity gradient
8058holds starting from the height
8059level&nbsp; defined by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>
8060(precisely: for all uv levels k, where zu(k) &gt;
8061q_vertical_gradient_level,
8062q_init(k) is set: q_init(k) = q_init(k-1) + dzu(k) * <b>q_vertical_gradient</b>)
8063up to the top boundary or up to the next height level defined
8064by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
8065A total of 10 different gradients for 11 height intervals (10 intervals
8066if <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>(1)
8067= <i>0.0</i>) can be asigned. The surface humidity is
8068assigned
8069via <a href="#q_surface">q_surface</a>. </p>
8070
8071
8072
8073
8074
8075     
8076     
8077     
8078     
8079      <p>Example:&nbsp; </p>
8080
8081
8082
8083
8084 
8085     
8086     
8087     
8088     
8089      <ul>
8090
8091
8092
8093
8094 
8095       
8096       
8097       
8098       
8099        <p><b>q_vertical_gradient</b>
8100= <i>0.001</i>, <i>0.0005</i>,&nbsp; <br>
8101
8102
8103
8104
8105
8106        <b>q_vertical_gradient_level</b> = <i>500.0</i>,
8107        <i>1000.0</i>,</p>
8108
8109
8110
8111
8112 
8113     
8114     
8115     
8116     
8117      </ul>
8118
8119
8120
8121
8122
8123That defines the humidity to be constant with height up to z =
8124500.0
8125m with a
8126value given by <a href="#q_surface">q_surface</a>.
8127For 500.0 m &lt; z &lt;= 1000.0 m the humidity gradient is
81280.001 / 100
8129m and for z &gt; 1000.0 m up to the top boundary it is
81300.0005 / 100 m (it is assumed that the assigned height levels
8131correspond with uv
8132levels). </td>
8133
8134
8135
8136
8137 </tr>
8138
8139
8140
8141
8142 <tr>
8143
8144
8145
8146
8147 <td style="vertical-align: top;"> 
8148     
8149     
8150     
8151     
8152      <p><a name="q_vertical_gradient_level"></a><b>q_vertical_gradient</b>
8153      <br>
8154
8155
8156
8157
8158 <b>_level</b></p>
8159
8160
8161
8162
8163 </td>
8164
8165
8166
8167
8168 <td style="vertical-align: top;">R (10)</td>
8169
8170
8171
8172
8173 <td style="vertical-align: top;"> 
8174     
8175     
8176     
8177     
8178      <p><i>10 *</i>&nbsp;
8179      <i>0.0</i></p>
8180
8181
8182
8183
8184 </td>
8185
8186
8187
8188
8189 <td style="vertical-align: top;"> 
8190     
8191     
8192     
8193     
8194      <p>Height level from
8195which on the humidity gradient defined by <a href="#q_vertical_gradient">q_vertical_gradient</a>
8196is effective (in m).&nbsp; </p>
8197
8198
8199
8200
8201 
8202     
8203     
8204     
8205     
8206      <p>The height levels
8207are to be assigned in ascending order. The
8208default values result in a humidity constant with height regardless of
8209the values of <a href="#q_vertical_gradient">q_vertical_gradient</a>
8210(unless the top boundary of the model is higher than 100000.0 m). For
8211the piecewise construction of humidity profiles see <a href="#q_vertical_gradient">q_vertical_gradient</a>.</p>
8212
8213
8214
8215
8216
8217      </td>
8218
8219
8220
8221
8222 </tr>
8223
8224
8225
8226
8227 <tr>
8228
8229
8230
8231
8232 <td style="vertical-align: top;"> 
8233     
8234     
8235     
8236     
8237      <p><a name="radiation"></a><b>radiation</b></p>
8238
8239
8240
8241
8242
8243      </td>
8244
8245
8246
8247
8248 <td style="vertical-align: top;">L</td>
8249
8250
8251
8252
8253
8254      <td style="vertical-align: top;"><i>.F.</i></td>
8255
8256
8257
8258
8259
8260      <td style="vertical-align: top;"> 
8261     
8262     
8263     
8264     
8265      <p>Parameter to
8266switch on longwave radiation cooling at
8267cloud-tops.&nbsp; </p>
8268
8269
8270
8271
8272 
8273     
8274     
8275     
8276     
8277      <p>Long-wave radiation
8278processes are parameterized by the
8279effective emissivity, which considers only the absorption and emission
8280of long-wave radiation at cloud droplets. The radiation scheme can be
8281used only with <a href="#cloud_physics">cloud_physics</a>
8282= .TRUE. .</p>
8283
8284
8285
8286
8287 </td>
8288
8289
8290
8291
8292 </tr>
8293
8294
8295
8296
8297 <tr>
8298
8299
8300
8301
8302 <td style="vertical-align: top;"> 
8303     
8304     
8305     
8306     
8307      <p><a name="random_generator"></a><b>random_generator</b></p>
8308
8309
8310
8311
8312
8313      </td>
8314
8315
8316
8317
8318 <td style="vertical-align: top;">C * 20</td>
8319
8320
8321
8322
8323
8324      <td style="vertical-align: top;"> 
8325     
8326     
8327     
8328     
8329      <p><i>'numerical</i><br>
8330
8331
8332
8333
8334
8335      <i>recipes'</i></p>
8336
8337
8338
8339
8340 </td>
8341
8342
8343
8344
8345 <td style="vertical-align: top;"> 
8346     
8347     
8348     
8349     
8350      <p>Random number
8351generator to be used for creating uniformly
8352distributed random numbers. <br>
8353
8354
8355
8356
8357 </p>
8358
8359
8360
8361
8362 
8363     
8364     
8365     
8366     
8367      <p>It is
8368used if random perturbations are to be imposed on the
8369velocity field or on the surface heat flux field (see <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>
8370and <a href="chapter_4.2.html#random_heatflux">random_heatflux</a>).
8371By default, the "Numerical Recipes" random number generator is used.
8372This one provides exactly the same order of random numbers on all
8373different machines and should be used in particular for comparison runs.<br>
8374
8375
8376
8377
8378
8379      <br>
8380
8381
8382
8383
8384
8385Besides, a system-specific generator is available ( <b>random_generator</b>
8386= <i>'system-specific')</i> which should particularly be
8387used for runs
8388on vector parallel computers (NEC), because the default generator
8389cannot be vectorized and therefore significantly drops down the code
8390performance on these machines.<br>
8391
8392
8393
8394
8395 </p>
8396
8397
8398
8399
8400 <span style="font-weight: bold;">Note:</span><br>
8401
8402
8403
8404
8405
8406Results from two otherwise identical model runs will not be comparable
8407one-to-one if they used different random number generators.</td>
8408
8409
8410
8411
8412 </tr>
8413
8414
8415
8416
8417
8418    <tr>
8419
8420
8421
8422
8423 <td style="vertical-align: top;"> 
8424     
8425     
8426     
8427     
8428      <p><a name="random_heatflux"></a><b>random_heatflux</b></p>
8429
8430
8431
8432
8433
8434      </td>
8435
8436
8437
8438
8439 <td style="vertical-align: top;">L</td>
8440
8441
8442
8443
8444
8445      <td style="vertical-align: top;"><i>.F.</i></td>
8446
8447
8448
8449
8450
8451      <td style="vertical-align: top;"> 
8452     
8453     
8454     
8455     
8456      <p>Parameter to
8457impose random perturbations on the internal two-dimensional near
8458surface heat flux field <span style="font-style: italic;">shf</span>.
8459      <br>
8460
8461
8462
8463
8464 </p>
8465
8466
8467
8468
8469If a near surface heat flux is used as bottom
8470boundary
8471condition (see <a href="#surface_heatflux">surface_heatflux</a>),
8472it is by default assumed to be horizontally homogeneous. Random
8473perturbations can be imposed on the internal
8474two-dimensional&nbsp;heat flux field <span style="font-style: italic;">shf</span> by assigning <b>random_heatflux</b>
8475= <i>.T.</i>. The disturbed heat flux field is calculated
8476by
8477multiplying the
8478values at each mesh point with a normally distributed random number
8479with a mean value and standard deviation of 1. This is repeated after
8480every timestep.<br>
8481
8482
8483
8484
8485 <br>
8486
8487
8488
8489
8490
8491In case of a non-flat <a href="#topography">topography</a>,&nbsp;assigning
8492      <b>random_heatflux</b>
8493= <i>.T.</i> imposes random perturbations on the
8494combined&nbsp;heat
8495flux field <span style="font-style: italic;">shf</span>
8496composed of <a href="#surface_heatflux">surface_heatflux</a>
8497at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
8498at the topography top face.</td>
8499
8500
8501
8502
8503 </tr>
8504
8505
8506
8507
8508 <tr>
8509
8510
8511
8512
8513 <td style="vertical-align: top;"> 
8514     
8515     
8516     
8517     
8518      <p><a name="rif_max"></a><b>rif_max</b></p>
8519
8520
8521
8522
8523
8524      </td>
8525
8526
8527
8528
8529 <td style="vertical-align: top;">R</td>
8530
8531
8532
8533
8534
8535      <td style="vertical-align: top;"><i>1.0</i></td>
8536
8537
8538
8539
8540
8541      <td style="vertical-align: top;"> 
8542     
8543     
8544     
8545     
8546      <p>Upper limit of
8547the flux-Richardson number.&nbsp; </p>
8548
8549
8550
8551
8552 
8553     
8554     
8555     
8556     
8557      <p>With the
8558Prandtl layer switched on (see <a href="#prandtl_layer">prandtl_layer</a>),
8559flux-Richardson numbers (rif) are calculated for z=z<sub>p</sub>
8560(k=1)
8561in the 3d-model (in the 1d model for all heights). Their values in
8562particular determine the
8563values of the friction velocity (1d- and 3d-model) and the values of
8564the eddy diffusivity (1d-model). With small wind velocities at the
8565Prandtl layer top or small vertical wind shears in the 1d-model, rif
8566can take up unrealistic large values. They are limited by an upper (<span style="font-weight: bold;">rif_max</span>) and lower
8567limit (see <a href="#rif_min">rif_min</a>)
8568for the flux-Richardson number. The condition <b>rif_max</b>
8569&gt; <b>rif_min</b>
8570must be met.</p>
8571
8572
8573
8574
8575 </td>
8576
8577
8578
8579
8580 </tr>
8581
8582
8583
8584
8585 <tr>
8586
8587
8588
8589
8590 <td style="vertical-align: top;"> 
8591     
8592     
8593     
8594     
8595      <p><a name="rif_min"></a><b>rif_min</b></p>
8596
8597
8598
8599
8600
8601      </td>
8602
8603
8604
8605
8606 <td style="vertical-align: top;">R</td>
8607
8608
8609
8610
8611
8612      <td style="vertical-align: top;"><i>- 5.0</i></td>
8613
8614
8615
8616
8617
8618      <td style="vertical-align: top;"> 
8619     
8620     
8621     
8622     
8623      <p>Lower limit of
8624the flux-Richardson number.&nbsp; </p>
8625
8626
8627
8628
8629 
8630     
8631     
8632     
8633     
8634      <p>For further
8635explanations see <a href="#rif_max">rif_max</a>.
8636The condition <b>rif_max</b> &gt; <b>rif_min </b>must
8637be met.</p>
8638
8639
8640
8641
8642 </td>
8643
8644
8645
8646
8647 </tr>
8648
8649
8650
8651
8652 <tr>
8653
8654
8655
8656
8657 <td style="vertical-align: top;"> 
8658     
8659     
8660     
8661     
8662      <p><a name="roughness_length"></a><b>roughness_length</b></p>
8663
8664
8665
8666
8667
8668      </td>
8669
8670
8671
8672
8673 <td style="vertical-align: top;">R</td>
8674
8675
8676
8677
8678
8679      <td style="vertical-align: top;"><i>0.1</i></td>
8680
8681
8682
8683
8684
8685      <td style="vertical-align: top;"> 
8686     
8687     
8688     
8689     
8690      <p>Roughness
8691length (in m).&nbsp; </p>
8692
8693
8694
8695
8696 
8697     
8698     
8699     
8700     
8701      <p>This parameter is
8702effective only in case that a Prandtl layer
8703is switched
8704on (see <a href="#prandtl_layer">prandtl_layer</a>).</p>
8705
8706
8707
8708
8709
8710      </td>
8711
8712
8713
8714
8715 </tr>
8716
8717
8718
8719
8720 <tr>
8721
8722
8723
8724
8725      <td style="vertical-align: top;"><a name="sa_surface"></a><span style="font-weight: bold;">sa_surface</span></td>
8726
8727
8728
8729
8730      <td style="vertical-align: top;">R</td>
8731
8732
8733
8734
8735      <td style="vertical-align: top;"><span style="font-style: italic;">35.0</span></td>
8736
8737
8738
8739
8740      <td style="vertical-align: top;"> 
8741     
8742     
8743     
8744     
8745      <p>Surface salinity (in psu).&nbsp;</p>
8746
8747
8748
8749
8750This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).
8751     
8752     
8753     
8754     
8755      <p>This
8756parameter assigns the value of the salinity <span style="font-weight: bold;">sa</span> at the sea surface (k=nzt)<b>.</b> Starting from this value,
8757the
8758initial vertical salinity profile is constructed from the surface down to the bottom of the model (k=0) by using&nbsp;<a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
8759and&nbsp;<a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level
8760      </a>.</p>
8761
8762
8763
8764
8765      </td>
8766
8767
8768
8769
8770    </tr>
8771
8772
8773
8774
8775    <tr>
8776
8777
8778
8779
8780      <td style="vertical-align: top;"><a name="sa_vertical_gradient"></a><span style="font-weight: bold;">sa_vertical_gradient</span></td>
8781
8782
8783
8784
8785      <td style="vertical-align: top;">R(10)</td>
8786
8787
8788
8789
8790      <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
8791
8792
8793
8794
8795      <td style="vertical-align: top;">
8796     
8797     
8798     
8799     
8800      <p>Salinity gradient(s) of the initial salinity profile (in psu
8801/ 100 m).&nbsp; </p>
8802
8803
8804
8805
8806 
8807     
8808     
8809     
8810     
8811      <p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
8812
8813
8814
8815
8816     
8817     
8818     
8819     
8820      <p>This salinity gradient
8821holds starting from the height&nbsp;
8822level defined by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>
8823(precisely: for all uv levels k where zu(k) &lt;
8824sa_vertical_gradient_level, sa_init(k) is set: sa_init(k) =
8825sa_init(k+1) - dzu(k+1) * <b>sa_vertical_gradient</b>) down to the bottom boundary or down to the next height level defined
8826by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>.
8827A total of 10 different gradients for 11 height intervals (10 intervals
8828if <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>(1)
8829= <i>0.0</i>) can be assigned. The surface salinity at k=nzt is
8830assigned via <a href="chapter_4.1.html#sa_surface">sa_surface</a>.&nbsp;
8831      </p>
8832
8833
8834
8835
8836 
8837     
8838     
8839     
8840     
8841      <p>Example:&nbsp; </p>
8842
8843
8844
8845
8846 
8847     
8848     
8849     
8850     
8851      <ul>
8852
8853
8854
8855
8856       
8857       
8858       
8859       
8860        <p><b>sa_vertical_gradient</b>
8861= <i>1.0</i>, <i>0.5</i>,&nbsp; <br>
8862
8863
8864
8865
8866
8867        <b>sa_vertical_gradient_level</b> = <i>-500.0</i>,
8868-<i>1000.0</i>,</p>
8869
8870
8871
8872
8873     
8874     
8875     
8876     
8877      </ul>
8878
8879
8880
8881
8882 
8883     
8884     
8885     
8886     
8887      <p>That
8888defines the salinity to be constant down to z = -500.0 m with a salinity given by <a href="chapter_4.1.html#sa_surface">sa_surface</a>.
8889For -500.0 m &lt; z &lt;= -1000.0 m the salinity gradient is
88901.0 psu /
8891100 m and for z &lt; -1000.0 m down to the bottom boundary it is
88920.5 psu / 100 m (it is assumed that the assigned height levels correspond
8893with uv levels).</p>
8894
8895
8896
8897
8898      </td>
8899
8900
8901
8902
8903    </tr>
8904
8905
8906
8907
8908    <tr>
8909
8910
8911
8912
8913      <td style="vertical-align: top;"><a name="sa_vertical_gradient_level"></a><span style="font-weight: bold;">sa_vertical_gradient_level</span></td>
8914
8915
8916
8917
8918      <td style="vertical-align: top;">R(10)</td>
8919
8920
8921
8922
8923      <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
8924
8925
8926
8927
8928      <td style="vertical-align: top;">
8929     
8930     
8931     
8932     
8933      <p>Height level from which on the salinity gradient defined by <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
8934is effective (in m).&nbsp; </p>
8935
8936
8937
8938
8939 
8940     
8941     
8942     
8943     
8944      <p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
8945
8946
8947
8948
8949     
8950     
8951     
8952     
8953      <p>The height levels have to be assigned in descending order. The
8954default values result in a constant salinity profile regardless of the
8955values of <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
8956(unless the bottom boundary of the model is lower than -100000.0 m).
8957For the piecewise construction of salinity profiles see <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>.</p>
8958
8959
8960
8961
8962      </td>
8963
8964
8965
8966
8967    </tr>
8968
8969
8970
8971
8972    <tr>
8973
8974
8975
8976
8977 <td style="vertical-align: top;"> 
8978     
8979     
8980     
8981     
8982      <p><a name="scalar_advec"></a><b>scalar_advec</b></p>
8983
8984
8985
8986
8987
8988      </td>
8989
8990
8991
8992
8993 <td style="vertical-align: top;">C * 10</td>
8994
8995
8996
8997
8998
8999      <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
9000
9001
9002
9003
9004
9005      <td style="vertical-align: top;"> 
9006     
9007     
9008     
9009     
9010      <p>Advection
9011scheme to be used for the scalar quantities.&nbsp; </p>
9012
9013
9014
9015
9016 
9017     
9018     
9019     
9020     
9021      <p>The
9022user can choose between the following schemes:<br>
9023
9024
9025
9026
9027 </p>
9028
9029
9030
9031
9032 
9033     
9034     
9035     
9036     
9037      <p><span style="font-style: italic;">'pw-scheme'</span><br>
9038
9039
9040
9041
9042
9043      </p>
9044
9045
9046
9047
9048 
9049     
9050     
9051     
9052     
9053      <div style="margin-left: 40px;">The scheme of
9054Piascek and
9055Williams (1970, J. Comp. Phys., 6,
9056392-405) with central differences in the form C3 is used.<br>
9057
9058
9059
9060
9061
9062If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
9063= <span style="font-style: italic;">'leapfrog+euler'</span>
9064the
9065advection scheme is - for the Euler-timestep - automatically switched
9066to an upstream-scheme. <br>
9067
9068
9069
9070
9071 </div>
9072
9073
9074
9075
9076 <br>
9077
9078
9079
9080
9081 
9082     
9083     
9084     
9085     
9086      <p><span style="font-style: italic;">'bc-scheme'</span><br>
9087
9088
9089
9090
9091
9092      </p>
9093
9094
9095
9096
9097 
9098     
9099     
9100     
9101     
9102      <div style="margin-left: 40px;">The Bott
9103scheme modified by
9104Chlond (1994, Mon.
9105Wea. Rev., 122, 111-125). This is a conservative monotonous scheme with
9106very small numerical diffusion and therefore very good conservation of
9107scalar flow features. The scheme however, is computationally very
9108expensive both because it is expensive itself and because it does (so
9109far) not allow specific code optimizations (e.g. cache optimization).
9110Choice of this
9111scheme forces the Euler timestep scheme to be used for the scalar
9112quantities. For output of horizontally averaged
9113profiles of the resolved / total heat flux, <a href="chapter_4.2.html#data_output_pr">data_output_pr</a>
9114= <i>'w*pt*BC'</i> / <i>'wptBC' </i>should
9115be used, instead of the
9116standard profiles (<span style="font-style: italic;">'w*pt*'</span>
9117and <span style="font-style: italic;">'wpt'</span>)
9118because these are
9119too inaccurate with this scheme. However, for subdomain analysis (see <a href="#statistic_regions">statistic_regions</a>)
9120exactly the reverse holds: here <i>'w*pt*BC'</i> and <i>'wptBC'</i>
9121show very large errors and should not be used.<br>
9122
9123
9124
9125
9126 <br>
9127
9128
9129
9130
9131
9132This scheme is not allowed for non-cyclic lateral boundary conditions
9133(see <a href="#bc_lr">bc_lr</a>
9134and <a href="#bc_ns">bc_ns</a>).<br>
9135
9136
9137
9138
9139 <br>
9140
9141
9142
9143
9144
9145      </div>
9146
9147
9148
9149
9150 <span style="font-style: italic;">'ups-scheme'</span><br>
9151
9152
9153
9154
9155
9156     
9157     
9158     
9159     
9160      <p style="margin-left: 40px;">The upstream-spline-scheme
9161is used
9162(see Mahrer and Pielke,
91631978: Mon. Wea. Rev., 106, 818-830). In opposite to the Piascek
9164Williams scheme, this is characterized by much better numerical
9165features (less numerical diffusion, better preservation of flux
9166structures, e.g. vortices), but computationally it is much more
9167expensive. In
9168addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
9169= <span style="font-style: italic;">'</span><i>euler'</i>),
9170i.e. the
9171timestep accuracy is only first order. For this reason the advection of
9172momentum (see <a href="#momentum_advec">momentum_advec</a>)
9173should then also be carried out with the upstream-spline scheme,
9174because otherwise the momentum would
9175be subject to large numerical diffusion due to the upstream
9176scheme.&nbsp; </p>
9177
9178
9179
9180
9181 
9182     
9183     
9184     
9185     
9186      <p style="margin-left: 40px;">Since
9187the cubic splines used tend
9188to overshoot under
9189certain circumstances, this effect must be adjusted by suitable
9190filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
9191      <a href="#long_filter_factor">long_filter_factor</a>,
9192      <a href="#ups_limit_pt">ups_limit_pt</a>, <a href="#ups_limit_u">ups_limit_u</a>, <a href="#ups_limit_v">ups_limit_v</a>, <a href="#ups_limit_w">ups_limit_w</a>).
9193This is always neccesssary for runs with stable stratification,
9194even if this stratification appears only in parts of the model
9195domain.&nbsp; </p>
9196
9197
9198
9199
9200 
9201     
9202     
9203     
9204     
9205      <p style="margin-left: 40px;">With
9206stable stratification the
9207upstream-upline scheme also produces gravity waves with large
9208amplitude, which must be
9209suitably damped (see <a href="chapter_4.2.html#rayleigh_damping_factor">rayleigh_damping_factor</a>).<br>
9210
9211
9212
9213
9214
9215      </p>
9216
9217
9218
9219
9220 
9221     
9222     
9223     
9224     
9225      <p style="margin-left: 40px;"><span style="font-weight: bold;">Important: </span>The&nbsp;
9226upstream-spline scheme is not implemented for humidity and passive
9227scalars (see&nbsp;<a href="#humidity">humidity</a>
9228and <a href="#passive_scalar">passive_scalar</a>)
9229and requires the use of a 2d-domain-decomposition. The last conditions
9230severely restricts code optimization on several machines leading to
9231very long execution times! This scheme is also not allowed for
9232non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
9233and <a href="#bc_ns">bc_ns</a>).</p>
9234
9235
9236
9237
9238      <br>
9239
9240
9241
9242
9243A
9244differing advection scheme can be choosed for the subgrid-scale TKE
9245using parameter <a href="chapter_4.1.html#use_upstream_for_tke">use_upstream_for_tke</a>.</td>
9246
9247
9248
9249
9250
9251    </tr>
9252
9253
9254
9255
9256 <tr>
9257
9258
9259
9260
9261 <td style="vertical-align: top;">
9262     
9263     
9264     
9265     
9266      <p><a name="statistic_regions"></a><b>statistic_regions</b></p>
9267
9268
9269
9270
9271
9272      </td>
9273
9274
9275
9276
9277 <td style="vertical-align: top;">I</td>
9278
9279
9280
9281
9282
9283      <td style="vertical-align: top;"><i>0</i></td>
9284
9285
9286
9287
9288
9289      <td style="vertical-align: top;"> 
9290     
9291     
9292     
9293     
9294      <p>Number of
9295additional user-defined subdomains for which
9296statistical analysis
9297and corresponding output (profiles, time series) shall be
9298made.&nbsp; </p>
9299
9300
9301
9302
9303 
9304     
9305     
9306     
9307     
9308      <p>By default, vertical profiles and
9309other statistical quantities
9310are calculated as horizontal and/or volume average of the total model
9311domain. Beyond that, these calculations can also be carried out for
9312subdomains which can be defined using the field <a href="chapter_3.5.3.html">rmask </a>within the
9313user-defined software
9314(see <a href="chapter_3.5.3.html">chapter
93153.5.3</a>). The number of these subdomains is determined with the
9316parameter <b>statistic_regions</b>. Maximum 9 additional
9317subdomains
9318are allowed. The parameter <a href="chapter_4.3.html#region">region</a>
9319can be used to assigned names (identifier) to these subdomains which
9320are then used in the headers
9321of the output files and plots.</p>
9322
9323
9324
9325
9326     
9327     
9328     
9329     
9330      <p>If the default NetCDF
9331output format is selected (see parameter <a href="chapter_4.2.html#data_output_format">data_output_format</a>),
9332data for the total domain and all defined subdomains are output to the
9333same file(s) (<a href="chapter_3.4.html#DATA_1D_PR_NETCDF">DATA_1D_PR_NETCDF</a>,
9334      <a href="chapter_3.4.html#DATA_1D_TS_NETCDF">DATA_1D_TS_NETCDF</a>).
9335In case of <span style="font-weight: bold;">statistic_regions</span>
9336&gt; <span style="font-style: italic;">0</span>,
9337data on the file for the different domains can be distinguished by a
9338suffix which is appended to the quantity names. Suffix 0 means data for
9339the total domain, suffix 1 means data for subdomain 1, etc.</p>
9340
9341
9342
9343
9344     
9345     
9346     
9347     
9348      <p>In
9349case of <span style="font-weight: bold;">data_output_format</span>
9350= <span style="font-style: italic;">'profil'</span>,
9351individual local files for profiles (<a href="chapter_3.4.html#PLOT1D_DATA">PLOT1D_DATA</a>)&nbsp;are
9352created for each subdomain. The individual subdomain files differ by
9353their name (the
9354number of the respective subdomain is attached, e.g.
9355PLOT1D_DATA_1). In this case the name of the file with the data of
9356the total domain is PLOT1D_DATA_0. If no subdomains
9357are declared (<b>statistic_regions</b> = <i>0</i>),
9358the name
9359PLOT1D_DATA is used (this must be considered in the
9360respective file connection statements of the <span style="font-weight: bold;">mrun</span> configuration
9361file).</p>
9362
9363
9364
9365
9366 </td>
9367
9368
9369
9370
9371 </tr>
9372
9373
9374
9375
9376 <tr>
9377
9378
9379
9380
9381 <td style="vertical-align: top;"> 
9382     
9383     
9384     
9385     
9386      <p><a name="surface_heatflux"></a><b>surface_heatflux</b></p>
9387
9388
9389
9390
9391
9392      </td>
9393
9394
9395
9396
9397 <td style="vertical-align: top;">R</td>
9398
9399
9400
9401
9402
9403      <td style="vertical-align: top;"><span style="font-style: italic;">no prescribed<br>
9404
9405
9406
9407
9408
9409heatflux<br>
9410
9411
9412
9413
9414 </span></td>
9415
9416
9417
9418
9419 <td style="vertical-align: top;"> 
9420     
9421     
9422     
9423     
9424      <p>Kinematic sensible
9425heat flux at the bottom surface (in K m/s).&nbsp; </p>
9426
9427
9428
9429
9430 
9431     
9432     
9433     
9434     
9435      <p>If
9436a value is assigned to this parameter, the internal two-dimensional
9437surface heat flux field <span style="font-style: italic;">shf</span>
9438is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>&nbsp;as
9439bottom (horizontally homogeneous) boundary condition for the
9440temperature equation. This additionally requires that a Neumann
9441condition must be used for the potential temperature (see <a href="#bc_pt_b">bc_pt_b</a>),
9442because otherwise the resolved scale may contribute to
9443the surface flux so that a constant value cannot be guaranteed. Also,
9444changes of the
9445surface temperature (see <a href="#pt_surface_initial_change">pt_surface_initial_change</a>)
9446are not allowed. The parameter <a href="#random_heatflux">random_heatflux</a>
9447can be used to impose random perturbations on the (homogeneous) surface
9448heat
9449flux field <span style="font-style: italic;">shf</span>.&nbsp;</p>
9450
9451
9452
9453
9454
9455     
9456     
9457     
9458     
9459      <p>
9460In case of a non-flat <a href="#topography">topography</a>,&nbsp;the
9461internal two-dimensional&nbsp;surface heat
9462flux field <span style="font-style: italic;">shf</span>
9463is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>
9464at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
9465at the topography top face.&nbsp;The parameter<a href="#random_heatflux"> random_heatflux</a>
9466can be used to impose random perturbations on this combined surface
9467heat
9468flux field <span style="font-style: italic;">shf</span>.&nbsp;
9469      </p>
9470
9471
9472
9473
9474 
9475     
9476     
9477     
9478     
9479      <p>If no surface heat flux is assigned, <span style="font-style: italic;">shf</span> is calculated
9480at each timestep by u<sub>*</sub> * theta<sub>*</sub>
9481(of course only with <a href="#prandtl_layer">prandtl_layer</a>
9482switched on). Here, u<sub>*</sub>
9483and theta<sub>*</sub> are calculated from the Prandtl law
9484assuming
9485logarithmic wind and temperature
9486profiles between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_pt_b">bc_pt_b</a>)
9487must be used as bottom boundary condition for the potential temperature.</p>
9488
9489
9490
9491
9492     
9493     
9494     
9495     
9496      <p>See
9497also <a href="#top_heatflux">top_heatflux</a>.</p>
9498
9499
9500
9501
9502
9503      </td>
9504
9505
9506
9507
9508 </tr>
9509
9510
9511
9512
9513 <tr>
9514
9515
9516
9517
9518 <td style="vertical-align: top;"> 
9519     
9520     
9521     
9522     
9523      <p><a name="surface_pressure"></a><b>surface_pressure</b></p>
9524
9525
9526
9527
9528
9529      </td>
9530
9531
9532
9533
9534 <td style="vertical-align: top;">R</td>
9535
9536
9537
9538
9539
9540      <td style="vertical-align: top;"><i>1013.25</i></td>
9541
9542
9543
9544
9545
9546      <td style="vertical-align: top;"> 
9547     
9548     
9549     
9550     
9551      <p>Atmospheric
9552pressure at the surface (in hPa).&nbsp; </p>
9553
9554
9555
9556
9557
9558Starting from this surface value, the vertical pressure
9559profile is calculated once at the beginning of the run assuming a
9560neutrally stratified
9561atmosphere. This is needed for
9562converting between the liquid water potential temperature and the
9563potential temperature (see <a href="#cloud_physics">cloud_physics</a><span style="text-decoration: underline;"></span>).</td>
9564
9565
9566
9567
9568
9569    </tr>
9570
9571
9572
9573
9574 <tr>
9575
9576
9577
9578
9579 <td style="vertical-align: top;">
9580     
9581     
9582     
9583     
9584      <p><a name="surface_scalarflux"></a><b>surface_scalarflux</b></p>
9585
9586
9587
9588
9589
9590      </td>
9591
9592
9593
9594
9595 <td style="vertical-align: top;">R</td>
9596
9597
9598
9599
9600
9601      <td style="vertical-align: top;"><i>0.0</i></td>
9602
9603
9604
9605
9606
9607      <td style="vertical-align: top;"> 
9608     
9609     
9610     
9611     
9612      <p>Scalar flux at
9613the surface (in kg/(m<sup>2</sup> s)).&nbsp; </p>
9614
9615
9616
9617
9618
9619     
9620     
9621     
9622     
9623      <p>If a non-zero value is assigned to this parameter, the
9624respective scalar flux value is used
9625as bottom (horizontally homogeneous) boundary condition for the scalar
9626concentration equation.&nbsp;This additionally requires that a
9627Neumann
9628condition must be used for the scalar concentration&nbsp;(see <a href="#bc_s_b">bc_s_b</a>),
9629because otherwise the resolved scale may contribute to
9630the surface flux so that a constant value cannot be guaranteed. Also,
9631changes of the
9632surface scalar concentration (see <a href="#s_surface_initial_change">s_surface_initial_change</a>)
9633are not allowed. <br>
9634
9635
9636
9637
9638 </p>
9639
9640
9641
9642
9643 
9644     
9645     
9646     
9647     
9648      <p>If no surface scalar
9649flux is assigned (<b>surface_scalarflux</b>
9650= <i>0.0</i>),
9651it is calculated at each timestep by u<sub>*</sub> * s<sub>*</sub>
9652(of course only with Prandtl layer switched on). Here, s<sub>*</sub>
9653is calculated from the Prandtl law assuming a logarithmic scalar
9654concentration
9655profile between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_s_b">bc_s_b</a>)
9656must be used as bottom boundary condition for the scalar concentration.</p>
9657
9658
9659
9660
9661
9662      </td>
9663
9664
9665
9666
9667 </tr>
9668
9669
9670
9671
9672 <tr>
9673
9674
9675
9676
9677 <td style="vertical-align: top;"> 
9678     
9679     
9680     
9681     
9682      <p><a name="surface_waterflux"></a><b>surface_waterflux</b></p>
9683
9684
9685
9686
9687
9688      </td>
9689
9690
9691
9692
9693 <td style="vertical-align: top;">R</td>
9694
9695
9696
9697
9698
9699      <td style="vertical-align: top;"><i>0.0</i></td>
9700
9701
9702
9703
9704
9705      <td style="vertical-align: top;"> 
9706     
9707     
9708     
9709     
9710      <p>Kinematic
9711water flux near the surface (in m/s).&nbsp; </p>
9712
9713
9714
9715
9716 
9717     
9718     
9719     
9720     
9721      <p>If
9722a non-zero value is assigned to this parameter, the
9723respective water flux value is used
9724as bottom (horizontally homogeneous) boundary condition for the
9725humidity equation. This additionally requires that a Neumann
9726condition must be used for the specific humidity / total water content
9727(see <a href="#bc_q_b">bc_q_b</a>),
9728because otherwise the resolved scale may contribute to
9729the surface flux so that a constant value cannot be guaranteed. Also,
9730changes of the
9731surface humidity (see <a href="#q_surface_initial_change">q_surface_initial_change</a>)
9732are not allowed.<br>
9733
9734
9735
9736
9737 </p>
9738
9739
9740
9741
9742 
9743     
9744     
9745     
9746     
9747      <p>If no surface water
9748flux is assigned (<b>surface_waterflux</b>
9749= <i>0.0</i>),
9750it is calculated at each timestep by u<sub>*</sub> * q<sub>*</sub>
9751(of course only with Prandtl layer switched on). Here, q<sub>*</sub>
9752is calculated from the Prandtl law assuming a logarithmic temperature
9753profile between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_q_b">bc_q_b</a>)
9754must be used as the bottom boundary condition for the humidity.</p>
9755
9756
9757
9758
9759
9760      </td>
9761
9762
9763
9764
9765 </tr>
9766
9767
9768
9769
9770 <tr>
9771
9772
9773
9774
9775 <td style="vertical-align: top;"> 
9776     
9777     
9778     
9779     
9780      <p><a name="s_surface"></a><b>s_surface</b></p>
9781
9782
9783
9784
9785
9786      </td>
9787
9788
9789
9790
9791 <td style="vertical-align: top;">R</td>
9792
9793
9794
9795
9796
9797      <td style="vertical-align: top;"><i>0.0</i></td>
9798
9799
9800
9801
9802
9803      <td style="vertical-align: top;"> 
9804     
9805     
9806     
9807     
9808      <p>Surface value
9809of the passive scalar (in kg/m<sup>3</sup>).&nbsp;<br>
9810
9811
9812
9813
9814
9815      </p>
9816
9817
9818
9819
9820
9821This parameter assigns the value of the passive scalar s at
9822the surface (k=0)<b>.</b> Starting from this value, the
9823initial vertical scalar concentration profile is constructed with<a href="#s_vertical_gradient">
9824s_vertical_gradient</a> and <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.</td>
9825
9826
9827
9828
9829
9830    </tr>
9831
9832
9833
9834
9835 <tr>
9836
9837
9838
9839
9840 <td style="vertical-align: top;">
9841     
9842     
9843     
9844     
9845      <p><a name="s_surface_initial_change"></a><b>s_surface_initial</b>
9846      <br>
9847
9848
9849
9850
9851 <b>_change</b></p>
9852
9853
9854
9855
9856 </td>
9857
9858
9859
9860
9861 <td style="vertical-align: top;">R</td>
9862
9863
9864
9865
9866 <td style="vertical-align: top;"><i>0.0</i></td>
9867
9868
9869
9870
9871
9872      <td style="vertical-align: top;"> 
9873     
9874     
9875     
9876     
9877      <p>Change in
9878surface scalar concentration to be made at the
9879beginning of the 3d run (in kg/m<sup>3</sup>).&nbsp; </p>
9880
9881
9882
9883
9884
9885     
9886     
9887     
9888     
9889      <p>If <b>s_surface_initial_change</b><i>&nbsp;</i>is
9890set to a
9891non-zero
9892value, the near surface scalar flux is not allowed to be given
9893simultaneously (see <a href="#surface_scalarflux">surface_scalarflux</a>).</p>
9894
9895
9896
9897
9898
9899      </td>
9900
9901
9902
9903
9904 </tr>
9905
9906
9907
9908
9909 <tr>
9910
9911
9912
9913
9914 <td style="vertical-align: top;"> 
9915     
9916     
9917     
9918     
9919      <p><a name="s_vertical_gradient"></a><b>s_vertical_gradient</b></p>
9920
9921
9922
9923
9924
9925      </td>
9926
9927
9928
9929
9930 <td style="vertical-align: top;">R (10)</td>
9931
9932
9933
9934
9935
9936      <td style="vertical-align: top;"><i>10 * 0</i><i>.0</i></td>
9937
9938
9939
9940
9941
9942      <td style="vertical-align: top;"> 
9943     
9944     
9945     
9946     
9947      <p>Scalar
9948concentration gradient(s) of the initial scalar
9949concentration profile (in kg/m<sup>3 </sup>/
9950100 m).&nbsp; </p>
9951
9952
9953
9954
9955 
9956     
9957     
9958     
9959     
9960      <p>The scalar gradient holds
9961starting from the height level
9962defined by <a href="#s_vertical_gradient_level">s_vertical_gradient_level
9963      </a>(precisely: for all uv levels k, where zu(k) &gt;
9964s_vertical_gradient_level, s_init(k) is set: s_init(k) = s_init(k-1) +
9965dzu(k) * <b>s_vertical_gradient</b>) up to the top
9966boundary or up to
9967the next height level defined by <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
9968A total of 10 different gradients for 11 height intervals (10 intervals
9969if <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>(1)
9970= <i>0.0</i>) can be assigned. The surface scalar value is
9971assigned
9972via <a href="#s_surface">s_surface</a>.<br>
9973
9974
9975
9976
9977 </p>
9978
9979
9980
9981
9982
9983     
9984     
9985     
9986     
9987      <p>Example:&nbsp; </p>
9988
9989
9990
9991
9992 
9993     
9994     
9995     
9996     
9997      <ul>
9998
9999
10000
10001
10002 
10003       
10004       
10005       
10006       
10007        <p><b>s_vertical_gradient</b>
10008= <i>0.1</i>, <i>0.05</i>,&nbsp; <br>
10009
10010
10011
10012
10013
10014        <b>s_vertical_gradient_level</b> = <i>500.0</i>,
10015        <i>1000.0</i>,</p>
10016
10017
10018
10019
10020 
10021     
10022     
10023     
10024     
10025      </ul>
10026
10027
10028
10029
10030 
10031     
10032     
10033     
10034     
10035      <p>That
10036defines the scalar concentration to be constant with
10037height up to z = 500.0 m with a value given by <a href="#s_surface">s_surface</a>.
10038For 500.0 m &lt; z &lt;= 1000.0 m the scalar gradient is 0.1
10039kg/m<sup>3 </sup>/ 100 m and for z &gt; 1000.0 m up to
10040the top
10041boundary it is 0.05 kg/m<sup>3 </sup>/ 100 m (it is
10042assumed that the
10043assigned height levels
10044correspond with uv
10045levels).</p>
10046
10047
10048
10049
10050 </td>
10051
10052
10053
10054
10055 </tr>
10056
10057
10058
10059
10060 <tr>
10061
10062
10063
10064
10065 <td style="vertical-align: top;"> 
10066     
10067     
10068     
10069     
10070      <p><a name="s_vertical_gradient_level"></a><b>s_vertical_gradient_</b>
10071      <br>
10072
10073
10074
10075
10076 <b>level</b></p>
10077
10078
10079
10080
10081 </td>
10082
10083
10084
10085
10086 <td style="vertical-align: top;">R (10)</td>
10087
10088
10089
10090
10091 <td style="vertical-align: top;"> 
10092     
10093     
10094     
10095     
10096      <p><i>10 *</i>
10097      <i>0.0</i></p>
10098
10099
10100
10101
10102 </td>
10103
10104
10105
10106
10107 <td style="vertical-align: top;"> 
10108     
10109     
10110     
10111     
10112      <p>Height level from
10113which on the scalar gradient defined by <a href="#s_vertical_gradient">s_vertical_gradient</a>
10114is effective (in m).&nbsp; </p>
10115
10116
10117
10118
10119 
10120     
10121     
10122     
10123     
10124      <p>The height levels
10125are to be assigned in ascending order. The
10126default values result in a scalar concentration constant with height
10127regardless of the values of <a href="#s_vertical_gradient">s_vertical_gradient</a>
10128(unless the top boundary of the model is higher than 100000.0 m). For
10129the
10130piecewise construction of scalar concentration profiles see <a href="#s_vertical_gradient">s_vertical_gradient</a>.</p>
10131
10132
10133
10134
10135
10136      </td>
10137
10138
10139
10140
10141 </tr>
10142
10143
10144
10145
10146 <tr>
10147
10148
10149
10150
10151 <td style="vertical-align: top;"> 
10152     
10153     
10154     
10155     
10156      <p><a name="timestep_scheme"></a><b>timestep_scheme</b></p>
10157
10158
10159
10160
10161
10162      </td>
10163
10164
10165
10166
10167 <td style="vertical-align: top;">C * 20</td>
10168
10169
10170
10171
10172
10173      <td style="vertical-align: top;"> 
10174     
10175     
10176     
10177     
10178      <p><i>'runge</i><br>
10179
10180
10181
10182
10183
10184      <i>kutta-3'</i></p>
10185
10186
10187
10188
10189 </td>
10190
10191
10192
10193
10194 <td style="vertical-align: top;"> 
10195     
10196     
10197     
10198     
10199      <p>Time step scheme to
10200be used for the integration of the prognostic
10201variables.&nbsp; </p>
10202
10203
10204
10205
10206 
10207     
10208     
10209     
10210     
10211      <p>The user can choose between
10212the following schemes:<br>
10213
10214
10215
10216
10217 </p>
10218
10219
10220
10221
10222 
10223     
10224     
10225     
10226     
10227      <p><span style="font-style: italic;">'runge-kutta-3'</span><br>
10228
10229
10230
10231
10232
10233      </p>
10234
10235
10236
10237
10238 
10239     
10240     
10241     
10242     
10243      <div style="margin-left: 40px;">Third order
10244Runge-Kutta scheme.<br>
10245
10246
10247
10248
10249
10250This scheme requires the use of <a href="#momentum_advec">momentum_advec</a>
10251= <a href="#scalar_advec">scalar_advec</a>
10252= '<i>pw-scheme'</i>. Please refer to the&nbsp;<a href="../tec/numerik.heiko/zeitschrittverfahren.pdf">documentation
10253on PALM's time integration schemes&nbsp;(28p., in German)</a>
10254fur further details.<br>
10255
10256
10257
10258
10259 </div>
10260
10261
10262
10263
10264 
10265     
10266     
10267     
10268     
10269      <p><span style="font-style: italic;">'runge-kutta-2'</span><br>
10270
10271
10272
10273
10274
10275      </p>
10276
10277
10278
10279
10280 
10281     
10282     
10283     
10284     
10285      <div style="margin-left: 40px;">Second order
10286Runge-Kutta scheme.<br>
10287
10288
10289
10290
10291
10292For special features see <b>timestep_scheme</b> = '<i>runge-kutta-3'</i>.<br>
10293
10294
10295
10296
10297
10298      </div>
10299
10300
10301
10302
10303 <br>
10304
10305
10306
10307
10308 <span style="font-style: italic;"><span style="font-style: italic;">'leapfrog'</span><br>
10309
10310
10311
10312
10313
10314      <br>
10315
10316
10317
10318
10319 </span> 
10320     
10321     
10322     
10323     
10324      <div style="margin-left: 40px;">Second
10325order leapfrog scheme.<br>
10326
10327
10328
10329
10330
10331Although this scheme requires a constant timestep (because it is
10332centered in time),&nbsp; is even applied in case of changes in
10333timestep. Therefore, only small
10334changes of the timestep are allowed (see <a href="#dt">dt</a>).
10335However, an Euler timestep is always used as the first timestep of an
10336initiali run. When using the Bott-Chlond scheme for scalar advection
10337(see <a href="#scalar_advec">scalar_advec</a>),
10338the prognostic equation for potential temperature will be calculated
10339with the Euler scheme, although the leapfrog scheme is switched
10340on.&nbsp; <br>
10341
10342
10343
10344
10345
10346The leapfrog scheme must not be us