source: palm/trunk/DOC/app/chapter_4.1.html @ 132

Last change on this file since 132 was 132, checked in by letzel, 16 years ago

Vertical profiles now based on nzb_s_inner; they are divided by
ngp_2dh_s_inner (scalars, procucts of scalars and velocity components) and
ngp_2dh (staggered velocity components and their products), respectively.

Allow new case bc_uv_t = 'dirichlet_0' for channel flow.

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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. </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. </td>
2093
2094
2095
2096
2097 </tr>
2098
2099
2100
2101
2102 <tr>
2103
2104
2105
2106
2107
2108      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="cloud_droplets"></a>cloud_droplets</span><br>
2109
2110
2111
2112
2113
2114      </td>
2115
2116
2117
2118
2119 <td style="vertical-align: top;">L<br>
2120
2121
2122
2123
2124 </td>
2125
2126
2127
2128
2129
2130      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span><br>
2131
2132
2133
2134
2135 </td>
2136
2137
2138
2139
2140
2141      <td style="vertical-align: top;">Parameter to switch on
2142usage of cloud droplets.<br>
2143
2144
2145
2146
2147 <br>
2148
2149
2150
2151
2152
2153<span style="font-weight: bold;"></span><span style="font-family: monospace;"></span>
2154
2155
2156
2157
2158Cloud 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
2159features (number of droplets, initial radius, etc.) can be steered with
2160the&nbsp; respective particle parameters (see e.g. <a href="#chapter_4.2.html#radius">radius</a>).
2161The real number of initial droplets in a grid cell is equal to the
2162initial 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>
2163      <span lang="en-GB"><font face="Thorndale, serif">and
2164      </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>)
2165times the <a href="#initial_weighting_factor">initial_weighting_factor</a>.<br>
2166
2167
2168
2169
2170
2171      <br>
2172
2173
2174
2175
2176
2177In case of using cloud droplets, the default condensation scheme in
2178PALM cannot be used, i.e. <a href="#cloud_physics">cloud_physics</a>
2179must be set <span style="font-style: italic;">.F.</span>.<br>
2180
2181
2182
2183
2184
2185      </td>
2186
2187
2188
2189
2190 </tr>
2191
2192
2193
2194
2195 <tr>
2196
2197
2198
2199
2200 <td style="vertical-align: top;"> 
2201     
2202     
2203     
2204     
2205      <p><a name="cloud_physics"></a><b>cloud_physics</b></p>
2206
2207
2208
2209
2210
2211      </td>
2212
2213
2214
2215
2216 <td style="vertical-align: top;">L<br>
2217
2218
2219
2220
2221 </td>
2222
2223
2224
2225
2226
2227      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
2228
2229
2230
2231
2232 <td style="vertical-align: top;"> 
2233     
2234     
2235     
2236     
2237      <p>Parameter to switch
2238on the condensation scheme.&nbsp; </p>
2239
2240
2241
2242
2243
2244For <b>cloud_physics =</b> <span style="font-style: italic;">.TRUE.</span>, equations
2245for the
2246liquid water&nbsp;
2247content and the liquid water potential temperature are solved instead
2248of those for specific humidity and potential temperature. Note
2249that a grid volume is assumed to be either completely saturated or
2250completely
2251unsaturated (0%-or-100%-scheme). A simple precipitation scheme can
2252additionally be switched on with parameter <a href="#precipitation">precipitation</a>.
2253Also cloud-top cooling by longwave radiation can be utilized (see <a href="#radiation">radiation</a>)<br>
2254
2255
2256
2257
2258 <b><br>
2259
2260
2261
2262
2263
2264cloud_physics =</b> <span style="font-style: italic;">.TRUE.
2265      </span>requires&nbsp;<a href="#humidity">humidity</a>
2266=<span style="font-style: italic;"> .TRUE.</span> .<br>
2267
2268
2269
2270
2271
2272Detailed information about the condensation scheme is given in the
2273description of the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM-1/Dokumentationen/Cloud_physics/wolken.pdf">cloud
2274physics module</a> (pdf-file, only in German).<br>
2275
2276
2277
2278
2279 <br>
2280
2281
2282
2283
2284
2285This condensation scheme is not allowed if cloud droplets are simulated
2286explicitly (see <a href="#cloud_droplets">cloud_droplets</a>).<br>
2287
2288
2289
2290
2291
2292      </td>
2293
2294
2295
2296
2297 </tr>
2298
2299
2300
2301
2302 <tr>
2303
2304
2305
2306
2307 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="conserve_volume_flow"></a>conserve_volume_flow</span></td>
2308
2309
2310
2311
2312
2313      <td style="vertical-align: top;">L</td>
2314
2315
2316
2317
2318 <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
2319
2320
2321
2322
2323 <td>Conservation
2324of volume flow in x- and y-direction.<br>
2325
2326
2327
2328
2329 <br>
2330
2331
2332
2333
2334 <span style="font-weight: bold;">conserve_volume_flow</span>
2335= <span style="font-style: italic;">.TRUE.</span>
2336guarantees that the volume flow through the xz- or yz-cross-section of
2337the total model domain remains constant (equal to the initial value at
2338t=0) throughout the run.<br>
2339
2340
2341
2342
2343
2344      </td>
2345
2346
2347
2348
2349 </tr>
2350
2351
2352
2353
2354 <tr>
2355
2356
2357
2358
2359 <td style="vertical-align: top;"> 
2360     
2361     
2362     
2363     
2364      <p><a name="cut_spline_overshoot"></a><b>cut_spline_overshoot</b></p>
2365
2366
2367
2368
2369
2370      </td>
2371
2372
2373
2374
2375 <td style="vertical-align: top;">L</td>
2376
2377
2378
2379
2380
2381      <td style="vertical-align: top;"><span style="font-style: italic;">.T.</span></td>
2382
2383
2384
2385
2386 <td style="vertical-align: top;"> 
2387     
2388     
2389     
2390     
2391      <p>Cuts off of
2392so-called overshoots, which can occur with the
2393upstream-spline scheme.&nbsp; </p>
2394
2395
2396
2397
2398 
2399     
2400     
2401     
2402     
2403      <p><font color="#000000">The cubic splines tend to overshoot in
2404case of discontinuous changes of variables between neighbouring grid
2405points.</font><font color="#ff0000"> </font><font color="#000000">This
2406may lead to errors in calculating the advection tendency.</font>
2407Choice
2408of <b>cut_spline_overshoot</b> = <i>.TRUE.</i>
2409(switched on by
2410default)
2411allows variable values not to exceed an interval defined by the
2412respective adjacent grid points. This interval can be adjusted
2413seperately for every prognostic variable (see initialization parameters
2414      <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>,
2415etc.). This might be necessary in case that the
2416default interval has a non-tolerable effect on the model
2417results.&nbsp; </p>
2418
2419
2420
2421
2422 
2423     
2424     
2425     
2426     
2427      <p>Overshoots may also be removed
2428using the parameters <a href="#ups_limit_e">ups_limit_e</a>,
2429      <a href="#ups_limit_pt">ups_limit_pt</a>,
2430etc. as well as by applying a long-filter (see <a href="#long_filter_factor">long_filter_factor</a>).</p>
2431
2432
2433
2434
2435
2436      </td>
2437
2438
2439
2440
2441 </tr>
2442
2443
2444
2445
2446 <tr>
2447
2448
2449
2450
2451 <td style="vertical-align: top;"> 
2452     
2453     
2454     
2455     
2456      <p><a name="damp_level_1d"></a><b>damp_level_1d</b></p>
2457
2458
2459
2460
2461
2462      </td>
2463
2464
2465
2466
2467 <td style="vertical-align: top;">R</td>
2468
2469
2470
2471
2472
2473      <td style="vertical-align: top;"><span style="font-style: italic;">zu(nz+1)</span></td>
2474
2475
2476
2477
2478
2479      <td style="vertical-align: top;"> 
2480     
2481     
2482     
2483     
2484      <p>Height where
2485the damping layer begins in the 1d-model
2486(in m).&nbsp; </p>
2487
2488
2489
2490
2491 
2492     
2493     
2494     
2495     
2496      <p>This parameter is used to
2497switch on a damping layer for the
24981d-model, which is generally needed for the damping of inertia
2499oscillations. Damping is done by gradually increasing the value
2500of the eddy diffusivities about 10% per vertical grid level
2501(starting with the value at the height given by <b>damp_level_1d</b>,
2502or possibly from the next grid pint above), i.e. K<sub>m</sub>(k+1)
2503=
25041.1 * K<sub>m</sub>(k).
2505The values of K<sub>m</sub> are limited to 10 m**2/s at
2506maximum.&nbsp; <br>
2507
2508
2509
2510
2511
2512This parameter only comes into effect if the 1d-model is switched on
2513for
2514the initialization of the 3d-model using <a href="#initializing_actions">initializing_actions</a>
2515= <span style="font-style: italic;">'set_1d-model_profiles'</span>.
2516      <br>
2517
2518
2519
2520
2521 </p>
2522
2523
2524
2525
2526 </td>
2527
2528
2529
2530
2531 </tr>
2532
2533
2534
2535
2536 <tr>
2537
2538
2539
2540
2541 <td style="vertical-align: top;"><a name="dissipation_1d"></a><span style="font-weight: bold;">dissipation_1d</span><br>
2542
2543
2544
2545
2546
2547      </td>
2548
2549
2550
2551
2552 <td style="vertical-align: top;">C*20<br>
2553
2554
2555
2556
2557
2558      </td>
2559
2560
2561
2562
2563 <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
2564
2565
2566
2567
2568 <span style="font-style: italic;">model'</span><br>
2569
2570
2571
2572
2573 </td>
2574
2575
2576
2577
2578
2579      <td style="vertical-align: top;">Calculation method for
2580the energy dissipation term in the TKE equation of the 1d-model.<br>
2581
2582
2583
2584
2585
2586      <br>
2587
2588
2589
2590
2591
2592By default the dissipation is calculated as in the 3d-model using diss
2593= (0.19 + 0.74 * l / l_grid) * e**1.5 / l.<br>
2594
2595
2596
2597
2598 <br>
2599
2600
2601
2602
2603
2604Setting <span style="font-weight: bold;">dissipation_1d</span>
2605= <span style="font-style: italic;">'detering'</span>
2606forces the dissipation to be calculated as diss = 0.064 * e**1.5 / l.<br>
2607
2608
2609
2610
2611
2612      </td>
2613
2614
2615
2616
2617 </tr>
2618
2619
2620
2621
2622
2623    <tr>
2624
2625
2626
2627
2628 <td style="vertical-align: top;"> 
2629     
2630     
2631     
2632     
2633      <p><a name="dt"></a><b>dt</b></p>
2634
2635
2636
2637
2638 </td>
2639
2640
2641
2642
2643
2644      <td style="vertical-align: top;">R</td>
2645
2646
2647
2648
2649 <td style="vertical-align: top;"><span style="font-style: italic;">variable</span></td>
2650
2651
2652
2653
2654
2655      <td style="vertical-align: top;"> 
2656     
2657     
2658     
2659     
2660      <p>Time step for
2661the 3d-model (in s).&nbsp; </p>
2662
2663
2664
2665
2666 
2667     
2668     
2669     
2670     
2671      <p>By default, (i.e.
2672if a Runge-Kutta scheme is used, see <a href="#timestep_scheme">timestep_scheme</a>)
2673the value of the time step is calculating after each time step
2674(following the time step criteria) and
2675used for the next step.</p>
2676
2677
2678
2679
2680 
2681     
2682     
2683     
2684     
2685      <p>If the user assigns <b>dt</b>
2686a value, then the time step is
2687fixed to this value throughout the whole run (whether it fulfills the
2688time step
2689criteria or not). However, changes are allowed for restart runs,
2690because <b>dt</b> can also be used as a <a href="chapter_4.2.html#dt_laufparameter">run
2691parameter</a>.&nbsp; </p>
2692
2693
2694
2695
2696 
2697     
2698     
2699     
2700     
2701      <p>In case that the
2702calculated time step meets the condition<br>
2703
2704
2705
2706
2707 </p>
2708
2709
2710
2711
2712 
2713     
2714     
2715     
2716     
2717      <ul>
2718
2719
2720
2721
2722
2723       
2724       
2725       
2726       
2727        <p><b>dt</b> &lt; 0.00001 * <a href="chapter_4.2.html#dt_max">dt_max</a> (with dt_max
2728= 20.0)</p>
2729
2730
2731
2732
2733 
2734     
2735     
2736     
2737     
2738      </ul>
2739
2740
2741
2742
2743 
2744     
2745     
2746     
2747     
2748      <p>the simulation will be
2749aborted. Such situations usually arise
2750in case of any numerical problem / instability which causes a
2751non-realistic increase of the wind speed.&nbsp; </p>
2752
2753
2754
2755
2756 
2757     
2758     
2759     
2760     
2761      <p>A
2762small time step due to a large mean horizontal windspeed
2763speed may be enlarged by using a coordinate transformation (see <a href="#galilei_transformation">galilei_transformation</a>),
2764in order to spare CPU time.<br>
2765
2766
2767
2768
2769 </p>
2770
2771
2772
2773
2774 
2775     
2776     
2777     
2778     
2779      <p>If the
2780leapfrog timestep scheme is used (see <a href="#timestep_scheme">timestep_scheme</a>)
2781a temporary time step value dt_new is calculated first, with dt_new = <a href="chapter_4.2.html#fcl_factor">cfl_factor</a>
2782* dt_crit where dt_crit is the maximum timestep allowed by the CFL and
2783diffusion condition. Next it is examined whether dt_new exceeds or
2784falls below the
2785value of the previous timestep by at
2786least +5 % / -2%. If it is smaller, <span style="font-weight: bold;">dt</span>
2787= dt_new is immediately used for the next timestep. If it is larger,
2788then <span style="font-weight: bold;">dt </span>=
27891.02 * dt_prev
2790(previous timestep) is used as the new timestep, however the time
2791step is only increased if the last change of the time step is dated
2792back at
2793least 30 iterations. If dt_new is located in the interval mentioned
2794above, then dt
2795does not change at all. By doing so, permanent time step changes as
2796well as large
2797sudden changes (increases) in the time step are avoided.</p>
2798
2799
2800
2801
2802 </td>
2803
2804
2805
2806
2807
2808    </tr>
2809
2810
2811
2812
2813 <tr>
2814
2815
2816
2817
2818 <td style="vertical-align: top;">
2819     
2820     
2821     
2822     
2823      <p><a name="dt_pr_1d"></a><b>dt_pr_1d</b></p>
2824
2825
2826
2827
2828
2829      </td>
2830
2831
2832
2833
2834 <td style="vertical-align: top;">R</td>
2835
2836
2837
2838
2839
2840      <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
2841
2842
2843
2844
2845
2846      <td style="vertical-align: top;"> 
2847     
2848     
2849     
2850     
2851      <p>Temporal
2852interval of vertical profile output of the 1D-model
2853(in s).&nbsp; </p>
2854
2855
2856
2857
2858 
2859     
2860     
2861     
2862     
2863      <p>Data are written in ASCII
2864format to file <a href="chapter_3.4.html#LIST_PROFIL_1D">LIST_PROFIL_1D</a>.
2865This parameter is only in effect if the 1d-model has been switched on
2866for the
2867initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
2868= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
2869
2870
2871
2872
2873
2874      </td>
2875
2876
2877
2878
2879 </tr>
2880
2881
2882
2883
2884 <tr>
2885
2886
2887
2888
2889 <td style="vertical-align: top;"> 
2890     
2891     
2892     
2893     
2894      <p><a name="dt_run_control_1d"></a><b>dt_run_control_1d</b></p>
2895
2896
2897
2898
2899
2900      </td>
2901
2902
2903
2904
2905 <td style="vertical-align: top;">R</td>
2906
2907
2908
2909
2910
2911      <td style="vertical-align: top;"><span style="font-style: italic;">60.0</span></td>
2912
2913
2914
2915
2916 <td style="vertical-align: top;"> 
2917     
2918     
2919     
2920     
2921      <p>Temporal interval of
2922runtime control output of the 1d-model
2923(in s).&nbsp; </p>
2924
2925
2926
2927
2928 
2929     
2930     
2931     
2932     
2933      <p>Data are written in ASCII
2934format to file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.
2935This parameter is only in effect if the 1d-model is switched on for the
2936initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
2937= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
2938
2939
2940
2941
2942
2943      </td>
2944
2945
2946
2947
2948 </tr>
2949
2950
2951
2952
2953 <tr>
2954
2955
2956
2957
2958 <td style="vertical-align: top;"> 
2959     
2960     
2961     
2962     
2963      <p><a name="dx"></a><b>dx</b></p>
2964
2965
2966
2967
2968
2969      </td>
2970
2971
2972
2973
2974 <td style="vertical-align: top;">R</td>
2975
2976
2977
2978
2979
2980      <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
2981
2982
2983
2984
2985 <td style="vertical-align: top;"> 
2986     
2987     
2988     
2989     
2990      <p>Horizontal grid
2991spacing along the x-direction (in m).&nbsp; </p>
2992
2993
2994
2995
2996 
2997     
2998     
2999     
3000     
3001      <p>Along
3002x-direction only a constant grid spacing is allowed.</p>
3003
3004
3005
3006
3007     
3008     
3009     
3010     
3011      <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>
3012and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
3013
3014
3015
3016
3017 </td>
3018
3019
3020
3021
3022
3023    </tr>
3024
3025
3026
3027
3028 <tr>
3029
3030
3031
3032
3033 <td style="vertical-align: top;">
3034     
3035     
3036     
3037     
3038      <p><a name="dy"></a><b>dy</b></p>
3039
3040
3041
3042
3043
3044      </td>
3045
3046
3047
3048
3049 <td style="vertical-align: top;">R</td>
3050
3051
3052
3053
3054
3055      <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
3056
3057
3058
3059
3060 <td style="vertical-align: top;"> 
3061     
3062     
3063     
3064     
3065      <p>Horizontal grid
3066spacing along the y-direction (in m).&nbsp; </p>
3067
3068
3069
3070
3071 
3072     
3073     
3074     
3075     
3076      <p>Along y-direction only a constant grid spacing is allowed.</p>
3077
3078
3079
3080
3081     
3082     
3083     
3084     
3085      <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>
3086and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
3087
3088
3089
3090
3091 </td>
3092
3093
3094
3095
3096
3097    </tr>
3098
3099
3100
3101
3102 <tr>
3103
3104
3105
3106
3107 <td style="vertical-align: top;">
3108     
3109     
3110     
3111     
3112      <p><a name="dz"></a><b>dz</b></p>
3113
3114
3115
3116
3117
3118      </td>
3119
3120
3121
3122
3123 <td style="vertical-align: top;">R</td>
3124
3125
3126
3127
3128
3129      <td style="vertical-align: top;"><br>
3130
3131
3132
3133
3134 </td>
3135
3136
3137
3138
3139 <td style="vertical-align: top;"> 
3140     
3141     
3142     
3143     
3144      <p>Vertical grid
3145spacing (in m).&nbsp; </p>
3146
3147
3148
3149
3150 
3151     
3152     
3153     
3154     
3155      <p>This parameter must be
3156assigned by the user, because no
3157default value is given.<br>
3158
3159
3160
3161
3162 </p>
3163
3164
3165
3166
3167 
3168     
3169     
3170     
3171     
3172      <p>By default, the
3173model uses constant grid spacing along z-direction, but it can be
3174stretched using the parameters <a href="#dz_stretch_level">dz_stretch_level</a>
3175and <a href="#dz_stretch_factor">dz_stretch_factor</a>.
3176In case of stretching, a maximum allowed grid spacing can be given by <a href="#dz_max">dz_max</a>.<br>
3177
3178
3179
3180
3181 </p>
3182
3183
3184
3185
3186 
3187     
3188     
3189     
3190     
3191      <p>Assuming
3192a constant <span style="font-weight: bold;">dz</span>,
3193the scalar levels (zu) are calculated directly by:&nbsp; </p>
3194
3195
3196
3197
3198
3199     
3200     
3201     
3202     
3203      <ul>
3204
3205
3206
3207
3208 
3209       
3210       
3211       
3212       
3213        <p>zu(0) = - dz * 0.5&nbsp; <br>
3214
3215
3216
3217
3218
3219zu(1) = dz * 0.5</p>
3220
3221
3222
3223
3224 
3225     
3226     
3227     
3228     
3229      </ul>
3230
3231
3232
3233
3234 
3235     
3236     
3237     
3238     
3239      <p>The w-levels lie
3240half between them:&nbsp; </p>
3241
3242
3243
3244
3245 
3246     
3247     
3248     
3249     
3250      <ul>
3251
3252
3253
3254
3255 
3256       
3257       
3258       
3259       
3260        <p>zw(k) =
3261( zu(k) + zu(k+1) ) * 0.5</p>
3262
3263
3264
3265
3266 
3267     
3268     
3269     
3270     
3271      </ul>
3272
3273
3274
3275
3276 </td>
3277
3278
3279
3280
3281 </tr>
3282
3283
3284
3285
3286
3287    <tr>
3288
3289
3290
3291
3292      <td style="vertical-align: top;"><a name="dz_max"></a><span style="font-weight: bold;">dz_max</span></td>
3293
3294
3295
3296
3297      <td style="vertical-align: top;">R</td>
3298
3299
3300
3301
3302      <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
3303
3304
3305
3306
3307      <td style="vertical-align: top;">Allowed maximum vertical grid
3308spacing (in m).<br>
3309
3310
3311
3312
3313      <br>
3314
3315
3316
3317
3318If the vertical grid is stretched
3319(see <a href="#dz_stretch_factor">dz_stretch_factor</a>
3320and <a href="#dz_stretch_level">dz_stretch_level</a>),
3321      <span style="font-weight: bold;">dz_max</span> can
3322be used to limit the vertical grid spacing.</td>
3323
3324
3325
3326
3327    </tr>
3328
3329
3330
3331
3332    <tr>
3333
3334
3335
3336
3337
3338      <td style="vertical-align: top;"> 
3339     
3340     
3341     
3342     
3343      <p><a name="dz_stretch_factor"></a><b>dz_stretch_factor</b></p>
3344
3345
3346
3347
3348
3349      </td>
3350
3351
3352
3353
3354 <td style="vertical-align: top;">R</td>
3355
3356
3357
3358
3359
3360      <td style="vertical-align: top;"><span style="font-style: italic;">1.08</span></td>
3361
3362
3363
3364
3365 <td style="vertical-align: top;"> 
3366     
3367     
3368     
3369     
3370      <p>Stretch factor for a
3371vertically stretched grid (see <a href="#dz_stretch_level">dz_stretch_level</a>).&nbsp;
3372      </p>
3373
3374
3375
3376
3377 
3378     
3379     
3380     
3381     
3382      <p>The stretch factor should not exceed a value of
3383approx. 1.10 -
33841.12, otherwise the discretization errors due to the stretched grid not
3385negligible any more. (refer Kalnay de Rivas)</p>
3386
3387
3388
3389
3390 </td>
3391
3392
3393
3394
3395 </tr>
3396
3397
3398
3399
3400
3401    <tr>
3402
3403
3404
3405
3406 <td style="vertical-align: top;"> 
3407     
3408     
3409     
3410     
3411      <p><a name="dz_stretch_level"></a><b>dz_stretch_level</b></p>
3412
3413
3414
3415
3416
3417      </td>
3418
3419
3420
3421
3422 <td style="vertical-align: top;">R</td>
3423
3424
3425
3426
3427
3428      <td style="vertical-align: top;"><span style="font-style: italic;">100000.0</span><br>
3429
3430
3431
3432
3433 </td>
3434
3435
3436
3437
3438
3439      <td style="vertical-align: top;"> 
3440     
3441     
3442     
3443     
3444      <p>Height level
3445above/below which the grid is to be stretched
3446vertically (in m).&nbsp; </p>
3447
3448
3449
3450
3451 
3452     
3453     
3454     
3455     
3456      <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
3457vertically. The vertical grid
3458spacings <a href="#dz">dz</a>
3459above this level are calculated as&nbsp; </p>
3460
3461
3462
3463
3464 
3465     
3466     
3467     
3468     
3469      <ul>
3470
3471
3472
3473
3474 
3475       
3476       
3477       
3478       
3479        <p><b>dz</b>(k+1)
3480= <b>dz</b>(k) * <a href="#dz_stretch_factor">dz_stretch_factor</a></p>
3481
3482
3483
3484
3485
3486     
3487     
3488     
3489     
3490      </ul>
3491
3492
3493
3494
3495 
3496     
3497     
3498     
3499     
3500      <p>and used as spacings for the scalar levels (zu).
3501The
3502w-levels are then defined as:&nbsp; </p>
3503
3504
3505
3506
3507 
3508     
3509     
3510     
3511     
3512      <ul>
3513
3514
3515
3516
3517 
3518       
3519       
3520       
3521       
3522        <p>zw(k)
3523= ( zu(k) + zu(k+1) ) * 0.5.
3524
3525 
3526     
3527      </p>
3528
3529
3530     
3531     
3532      </ul>
3533
3534
3535     
3536     
3537      <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
3538vertically. The vertical grid
3539spacings <a href="chapter_4.1.html#dz">dz</a> below this level are calculated correspondingly as
3540
3541 
3542     
3543      </p>
3544
3545
3546     
3547     
3548      <ul>
3549
3550
3551       
3552       
3553        <p><b>dz</b>(k-1)
3554= <b>dz</b>(k) * <a href="chapter_4.1.html#dz_stretch_factor">dz_stretch_factor</a>.</p>
3555
3556
3557     
3558     
3559      </ul>
3560
3561
3562
3563
3564 </td>
3565
3566
3567
3568
3569 </tr>
3570
3571
3572
3573
3574
3575    <tr>
3576
3577
3578
3579      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_init"></a>e_init</span></td>
3580
3581
3582
3583      <td style="vertical-align: top;">R</td>
3584
3585
3586
3587      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
3588
3589
3590
3591      <td>Initial subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
3592
3593
3594
3595
3596
3597      <br>
3598
3599
3600
3601
3602This
3603option 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>
3604
3605
3606
3607    </tr>
3608
3609
3610
3611    <tr>
3612
3613
3614
3615
3616 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_min"></a>e_min</span></td>
3617
3618
3619
3620
3621
3622      <td style="vertical-align: top;">R</td>
3623
3624
3625
3626
3627 <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
3628
3629
3630
3631
3632 <td>Minimum
3633subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
3634
3635
3636
3637
3638
3639      <br>
3640
3641
3642
3643
3644This
3645option&nbsp;adds artificial viscosity to the flow by ensuring that
3646the
3647subgrid-scale TKE does not fall below the minimum threshold <span style="font-weight: bold;">e_min</span>.</td>
3648
3649
3650
3651
3652 </tr>
3653
3654
3655
3656
3657
3658    <tr>
3659
3660
3661
3662
3663 <td style="vertical-align: top;"> 
3664     
3665     
3666     
3667     
3668      <p><a name="end_time_1d"></a><b>end_time_1d</b></p>
3669
3670
3671
3672
3673
3674      </td>
3675
3676
3677
3678
3679 <td style="vertical-align: top;">R</td>
3680
3681
3682
3683
3684
3685      <td style="vertical-align: top;"><span style="font-style: italic;">864000.0</span><br>
3686
3687
3688
3689
3690 </td>
3691
3692
3693
3694
3695
3696      <td style="vertical-align: top;"> 
3697     
3698     
3699     
3700     
3701      <p>Time to be
3702simulated for the 1d-model (in s).&nbsp; </p>
3703
3704
3705
3706
3707 
3708     
3709     
3710     
3711     
3712      <p>The
3713default value corresponds to a simulated time of 10 days.
3714Usually, after such a period the inertia oscillations have completely
3715decayed and the solution of the 1d-model can be regarded as stationary
3716(see <a href="#damp_level_1d">damp_level_1d</a>).
3717This parameter is only in effect if the 1d-model is switched on for the
3718initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
3719= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
3720
3721
3722
3723
3724
3725      </td>
3726
3727
3728
3729
3730 </tr>
3731
3732
3733
3734
3735 <tr>
3736
3737
3738
3739
3740 <td style="vertical-align: top;"> 
3741     
3742     
3743     
3744     
3745      <p><a name="fft_method"></a><b>fft_method</b></p>
3746
3747
3748
3749
3750
3751      </td>
3752
3753
3754
3755
3756 <td style="vertical-align: top;">C * 20</td>
3757
3758
3759
3760
3761
3762      <td style="vertical-align: top;"><span style="font-style: italic;">'system-</span><br style="font-style: italic;">
3763
3764
3765
3766
3767 <span style="font-style: italic;">specific'</span></td>
3768
3769
3770
3771
3772
3773      <td style="vertical-align: top;"> 
3774     
3775     
3776     
3777     
3778      <p>FFT-method to
3779be used.<br>
3780
3781
3782
3783
3784 </p>
3785
3786
3787
3788
3789 
3790     
3791     
3792     
3793     
3794      <p><br>
3795
3796
3797
3798
3799
3800The fast fourier transformation (FFT) is used for solving the
3801perturbation pressure equation with a direct method (see <a href="chapter_4.2.html#psolver">psolver</a>)
3802and for calculating power spectra (see optional software packages,
3803section <a href="chapter_4.2.html#spectra_package">4.2</a>).</p>
3804
3805
3806
3807
3808
3809     
3810     
3811     
3812     
3813      <p><br>
3814
3815
3816
3817
3818
3819By default, system-specific, optimized routines from external
3820vendor libraries are used. However, these are available only on certain
3821computers and there are more or less severe restrictions concerning the
3822number of gridpoints to be used with them.<br>
3823
3824
3825
3826
3827 </p>
3828
3829
3830
3831
3832 
3833     
3834     
3835     
3836     
3837      <p>There
3838are two other PALM internal methods available on every
3839machine (their respective source code is part of the PALM source code):</p>
3840
3841
3842
3843
3844
3845     
3846     
3847     
3848     
3849      <p>1.: The <span style="font-weight: bold;">Temperton</span>-method
3850from Clive Temperton (ECWMF) which is computationally very fast and
3851switched on with <b>fft_method</b> = <span style="font-style: italic;">'temperton-algorithm'</span>.
3852The number of horizontal gridpoints (nx+1, ny+1) to be used with this
3853method must be composed of prime factors 2, 3 and 5.<br>
3854
3855
3856
3857
3858 </p>
3859
3860
3861
3862
3863
38642.: The <span style="font-weight: bold;">Singleton</span>-method
3865which is very slow but has no restrictions concerning the number of
3866gridpoints to be used with, switched on with <b>fft_method</b>
3867= <span style="font-style: italic;">'singleton-algorithm'</span>.
3868      </td>
3869
3870
3871
3872
3873 </tr>
3874
3875
3876
3877
3878 <tr>
3879
3880
3881
3882
3883 <td style="vertical-align: top;"> 
3884     
3885     
3886     
3887     
3888      <p><a name="galilei_transformation"></a><b>galilei_transformation</b></p>
3889
3890
3891
3892
3893
3894      </td>
3895
3896
3897
3898
3899 <td style="vertical-align: top;">L</td>
3900
3901
3902
3903
3904
3905      <td style="vertical-align: top;"><i>.F.</i></td>
3906
3907
3908
3909
3910
3911      <td style="vertical-align: top;">Application of a
3912Galilei-transformation to the
3913coordinate
3914system of the model.<br>
3915
3916
3917
3918
3919     
3920     
3921     
3922     
3923      <p>With <b>galilei_transformation</b>
3924= <i>.T.,</i> a so-called
3925Galilei-transformation is switched on which ensures that the coordinate
3926system of the model is moved along with the geostrophical wind.
3927Alternatively, the model domain can be moved along with the averaged
3928horizontal wind (see <a href="#use_ug_for_galilei_tr">use_ug_for_galilei_tr</a>,
3929this can and will naturally change in time). With this method,
3930numerical inaccuracies of the Piascek - Williams - scheme (concerns in
3931particular the momentum advection) are minimized. Beyond that, in the
3932majority of cases the lower relative velocities in the moved system
3933permit a larger time step (<a href="#dt">dt</a>).
3934Switching the transformation on is only worthwhile if the geostrophical
3935wind (ug, vg)
3936and the averaged horizontal wind clearly deviate from the value 0. In
3937each case, the distance the coordinate system has been moved is written
3938to the file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.&nbsp;
3939      </p>
3940
3941
3942
3943
3944 
3945     
3946     
3947     
3948     
3949      <p>Non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
3950and <a href="#bc_ns">bc_ns</a>), the specification
3951of a gestrophic
3952wind that is not constant with height
3953as well as e.g. stationary inhomogeneities at the bottom boundary do
3954not allow the use of this transformation.</p>
3955
3956
3957
3958
3959 </td>
3960
3961
3962
3963
3964 </tr>
3965
3966
3967
3968
3969
3970    <tr>
3971
3972
3973
3974
3975 <td style="vertical-align: top;"> 
3976     
3977     
3978     
3979     
3980      <p><a name="grid_matching"></a><b>grid_matching</b></p>
3981
3982
3983
3984
3985
3986      </td>
3987
3988
3989
3990
3991 <td style="vertical-align: top;">C * 6</td>
3992
3993
3994
3995
3996
3997      <td style="vertical-align: top;"><span style="font-style: italic;">'match'</span></td>
3998
3999
4000
4001
4002 <td style="vertical-align: top;">Variable to adjust the
4003subdomain
4004sizes in parallel runs.<br>
4005
4006
4007
4008
4009 <br>
4010
4011
4012
4013
4014
4015For <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>,
4016the subdomains are forced to have an identical
4017size on all processors. In this case the processor numbers in the
4018respective directions of the virtual processor net must fulfill certain
4019divisor conditions concerning the grid point numbers in the three
4020directions (see <a href="#nx">nx</a>, <a href="#ny">ny</a>
4021and <a href="#nz">nz</a>).
4022Advantage of this method is that all PEs bear the same computational
4023load.<br>
4024
4025
4026
4027
4028 <br>
4029
4030
4031
4032
4033
4034There is no such restriction by default, because then smaller
4035subdomains are allowed on those processors which
4036form the right and/or north boundary of the virtual processor grid. On
4037all other processors the subdomains are of same size. Whether smaller
4038subdomains are actually used, depends on the number of processors and
4039the grid point numbers used. Information about the respective settings
4040are 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>
4041
4042
4043
4044
4045
4046      <br>
4047
4048
4049
4050
4051
4052When 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>)
4053only <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>
4054is allowed.<br>
4055
4056
4057
4058
4059 <br>
4060
4061
4062
4063
4064 <b>Note:</b><br>
4065
4066
4067
4068
4069
4070In some cases for small processor numbers there may be a very bad load
4071balancing among the
4072processors which may reduce the performance of the code.</td>
4073
4074
4075
4076
4077 </tr>
4078
4079
4080
4081
4082
4083    <tr>
4084
4085
4086
4087
4088 <td style="vertical-align: top;"><a name="inflow_disturbance_begin"></a><b>inflow_disturbance_<br>
4089
4090
4091
4092
4093
4094begin</b></td>
4095
4096
4097
4098
4099 <td style="vertical-align: top;">I</td>
4100
4101
4102
4103
4104
4105      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(10,</span><br style="font-style: italic;">
4106
4107
4108
4109
4110 <span style="font-style: italic;">nx/2 or ny/2)</span></td>
4111
4112
4113
4114
4115
4116      <td style="vertical-align: top;">Lower
4117limit of the horizontal range for which random perturbations are to be
4118imposed on the horizontal velocity field (gridpoints).<br>
4119
4120
4121
4122
4123 <br>
4124
4125
4126
4127
4128
4129If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
4130or <a href="#bc_ns">bc_ns</a>),
4131this parameter gives the gridpoint number (counted horizontally from
4132the inflow)&nbsp; from which on perturbations are imposed on the
4133horizontal velocity field. Perturbations must be switched on with
4134parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
4135
4136
4137
4138
4139
4140    </tr>
4141
4142
4143
4144
4145 <tr>
4146
4147
4148
4149
4150 <td style="vertical-align: top;"><a name="inflow_disturbance_end"></a><b>inflow_disturbance_<br>
4151
4152
4153
4154
4155
4156end</b></td>
4157
4158
4159
4160
4161 <td style="vertical-align: top;">I</td>
4162
4163
4164
4165
4166
4167      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(100,</span><br style="font-style: italic;">
4168
4169
4170
4171
4172 <span style="font-style: italic;">3/4*nx or</span><br style="font-style: italic;">
4173
4174
4175
4176
4177 <span style="font-style: italic;">3/4*ny)</span></td>
4178
4179
4180
4181
4182 <td style="vertical-align: top;">Upper
4183limit of the horizontal range for which random perturbations are
4184to be imposed on the horizontal velocity field (gridpoints).<br>
4185
4186
4187
4188
4189 <br>
4190
4191
4192
4193
4194
4195If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
4196or <a href="#bc_ns">bc_ns</a>),
4197this parameter gives the gridpoint number (counted horizontally from
4198the inflow)&nbsp; unto which perturbations are imposed on the
4199horizontal
4200velocity field. Perturbations must be switched on with parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
4201
4202
4203
4204
4205
4206    </tr>
4207
4208
4209
4210
4211 <tr>
4212
4213
4214
4215
4216 <td style="vertical-align: top;">
4217     
4218     
4219     
4220     
4221      <p><a name="initializing_actions"></a><b>initializing_actions</b></p>
4222
4223
4224
4225
4226
4227      </td>
4228
4229
4230
4231
4232 <td style="vertical-align: top;">C * 100</td>
4233
4234
4235
4236
4237
4238      <td style="vertical-align: top;"><br>
4239
4240
4241
4242
4243 </td>
4244
4245
4246
4247
4248 <td style="vertical-align: top;"> 
4249     
4250     
4251     
4252     
4253      <p style="font-style: normal;">Initialization actions
4254to be carried out.&nbsp; </p>
4255
4256
4257
4258
4259 
4260     
4261     
4262     
4263     
4264      <p style="font-style: normal;">This parameter does not have a
4265default value and therefore must be assigned with each model run. For
4266restart runs <b>initializing_actions</b> = <span style="font-style: italic;">'read_restart_data'</span>
4267must be set. For the initial run of a job chain the following values
4268are allowed:&nbsp; </p>
4269
4270
4271
4272
4273 
4274     
4275     
4276     
4277     
4278      <p style="font-style: normal;"><span style="font-style: italic;">'set_constant_profiles'</span>
4279      </p>
4280
4281
4282
4283
4284 
4285     
4286     
4287     
4288     
4289      <ul>
4290
4291
4292
4293
4294 
4295       
4296       
4297       
4298       
4299        <p>A horizontal wind profile consisting
4300of linear sections (see <a href="#ug_surface">ug_surface</a>,
4301        <a href="#ug_vertical_gradient">ug_vertical_gradient</a>,
4302        <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>
4303and <a href="#vg_surface">vg_surface</a>, <a href="#vg_vertical_gradient">vg_vertical_gradient</a>,
4304        <a href="#vg_vertical_gradient_level">vg_vertical_gradient_level</a>,
4305respectively) as well as a vertical temperature (humidity) profile
4306consisting of
4307linear sections (see <a href="#pt_surface">pt_surface</a>,
4308        <a href="#pt_vertical_gradient">pt_vertical_gradient</a>,
4309        <a href="#q_surface">q_surface</a>
4310and <a href="#q_vertical_gradient">q_vertical_gradient</a>)
4311are assumed as initial profiles. The subgrid-scale TKE is set to 0 but K<sub>m</sub>
4312and K<sub>h</sub> are set to very small values because
4313otherwise no TKE
4314would be generated.</p>
4315
4316
4317
4318
4319 
4320     
4321     
4322     
4323     
4324      </ul>
4325
4326
4327
4328
4329 
4330     
4331     
4332     
4333     
4334      <p style="font-style: italic;">'set_1d-model_profiles' </p>
4335
4336
4337
4338
4339
4340     
4341     
4342     
4343     
4344      <ul>
4345
4346
4347
4348
4349 
4350       
4351       
4352       
4353       
4354        <p>The arrays of the 3d-model are initialized with
4355the
4356(stationary) solution of the 1d-model. These are the variables e, kh,
4357km, u, v and with Prandtl layer switched on rif, us, usws, vsws. The
4358temperature (humidity) profile consisting of linear sections is set as
4359for 'set_constant_profiles' and assumed as constant in time within the
43601d-model. For steering of the 1d-model a set of parameters with suffix
4361"_1d" (e.g. <a href="#end_time_1d">end_time_1d</a>,
4362        <a href="#damp_level_1d">damp_level_1d</a>)
4363is available.</p>
4364
4365
4366
4367
4368 
4369     
4370     
4371     
4372     
4373      </ul>
4374
4375
4376
4377
4378 
4379     
4380     
4381     
4382     
4383      <p><span style="font-style: italic;">'by_user'</span></p>
4384
4385
4386
4387
4388     
4389     
4390     
4391     
4392      <p style="margin-left: 40px;">The initialization of the arrays
4393of the 3d-model is under complete control of the user and has to be
4394done in routine <a href="chapter_3.5.1.html#user_init_3d_model">user_init_3d_model</a>
4395of the user-interface.<span style="font-style: italic;"></span></p>
4396
4397
4398
4399
4400     
4401     
4402     
4403     
4404      <p><span style="font-style: italic;">'initialize_vortex'</span>
4405      </p>
4406
4407
4408
4409
4410 
4411     
4412     
4413     
4414     
4415      <div style="margin-left: 40px;">The initial
4416velocity field of the
44173d-model corresponds to a
4418Rankine-vortex with vertical axis. This setting may be used to test
4419advection 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>)
4420are necessary. In order not to distort the vortex, an initial
4421horizontal wind profile constant
4422with height is necessary (to be set by <b>initializing_actions</b>
4423= <span style="font-style: italic;">'set_constant_profiles'</span>)
4424and some other conditions have to be met (neutral stratification,
4425diffusion must be
4426switched off, see <a href="#km_constant">km_constant</a>).
4427The center of the vortex is located at jc = (nx+1)/2. It
4428extends from k = 0 to k = nz+1. Its radius is 8 * <a href="#dx">dx</a>
4429and the exponentially decaying part ranges to 32 * <a href="#dx">dx</a>
4430(see init_rankine.f90). </div>
4431
4432
4433
4434
4435 
4436     
4437     
4438     
4439     
4440      <p><span style="font-style: italic;">'initialize_ptanom'</span>
4441      </p>
4442
4443
4444
4445
4446 
4447     
4448     
4449     
4450     
4451      <ul>
4452
4453
4454
4455
4456 
4457       
4458       
4459       
4460       
4461        <p>A 2d-Gauss-like shape disturbance
4462(x,y) is added to the
4463initial temperature field with radius 10.0 * <a href="#dx">dx</a>
4464and center at jc = (nx+1)/2. This may be used for tests of scalar
4465advection schemes
4466(see <a href="#scalar_advec">scalar_advec</a>).
4467Such tests require a horizontal wind profile constant with hight and
4468diffusion
4469switched off (see <span style="font-style: italic;">'initialize_vortex'</span>).
4470Additionally, the buoyancy term
4471must be switched of in the equation of motion&nbsp; for w (this
4472requires the user to comment out the call of <span style="font-family: monospace;">buoyancy</span> in the
4473source code of <span style="font-family: monospace;">prognostic_equations.f90</span>).</p>
4474
4475
4476
4477
4478
4479     
4480     
4481     
4482     
4483      </ul>
4484
4485
4486
4487
4488 
4489     
4490     
4491     
4492     
4493      <p style="font-style: normal;">Values may be
4494combined, e.g. <b>initializing_actions</b> = <span style="font-style: italic;">'set_constant_profiles
4495initialize_vortex'</span>, but the values of <span style="font-style: italic;">'set_constant_profiles'</span>,
4496      <span style="font-style: italic;">'set_1d-model_profiles'</span>
4497, and <span style="font-style: italic;">'by_user'</span>
4498must not be given at the same time.</p>
4499
4500
4501
4502
4503 
4504     
4505     
4506     
4507     
4508      <p style="font-style: italic;"> </p>
4509
4510
4511
4512
4513 </td>
4514
4515
4516
4517
4518 </tr>
4519
4520
4521
4522
4523
4524    <tr>
4525
4526
4527
4528
4529 <td style="vertical-align: top;"> 
4530     
4531     
4532     
4533     
4534      <p><a name="km_constant"></a><b>km_constant</b></p>
4535
4536
4537
4538
4539
4540      </td>
4541
4542
4543
4544
4545 <td style="vertical-align: top;">R</td>
4546
4547
4548
4549
4550
4551      <td style="vertical-align: top;"><i>variable<br>
4552
4553
4554
4555
4556
4557(computed from TKE)</i></td>
4558
4559
4560
4561
4562 <td style="vertical-align: top;"> 
4563     
4564     
4565     
4566     
4567      <p>Constant eddy
4568diffusivities are used (laminar
4569simulations).&nbsp; </p>
4570
4571
4572
4573
4574 
4575     
4576     
4577     
4578     
4579      <p>If this parameter is
4580specified, both in the 1d and in the
45813d-model constant values for the eddy diffusivities are used in
4582space and time with K<sub>m</sub> = <b>km_constant</b>
4583and K<sub>h</sub> = K<sub>m</sub> / <a href="chapter_4.2.html#prandtl_number">prandtl_number</a>.
4584The prognostic equation for the subgrid-scale TKE is switched off.
4585Constant eddy diffusivities are only allowed with the Prandtl layer (<a href="#prandtl_layer">prandtl_layer</a>)
4586switched off.</p>
4587
4588
4589
4590
4591 </td>
4592
4593
4594
4595
4596 </tr>
4597
4598
4599
4600
4601 <tr>
4602
4603
4604
4605
4606 <td style="vertical-align: top;"> 
4607     
4608     
4609     
4610     
4611      <p><a name="km_damp_max"></a><b>km_damp_max</b></p>
4612
4613
4614
4615
4616
4617      </td>
4618
4619
4620
4621
4622 <td style="vertical-align: top;">R</td>
4623
4624
4625
4626
4627
4628      <td style="vertical-align: top;"><span style="font-style: italic;">0.5*(dx
4629or dy)</span></td>
4630
4631
4632
4633
4634 <td style="vertical-align: top;">Maximum
4635diffusivity used for filtering the velocity field in the vicinity of
4636the outflow (in m<sup>2</sup>/s).<br>
4637
4638
4639
4640
4641 <br>
4642
4643
4644
4645
4646
4647When using non-cyclic lateral boundaries (see <a href="#bc_lr">bc_lr</a>
4648or <a href="#bc_ns">bc_ns</a>),
4649a smoothing has to be applied to the
4650velocity field in the vicinity of the outflow in order to suppress any
4651reflections of outgoing disturbances. Smoothing is done by increasing
4652the eddy diffusivity along the horizontal direction which is
4653perpendicular to the outflow boundary. Only velocity components
4654parallel to the outflow boundary are filtered (e.g. v and w, if the
4655outflow is along x). Damping is applied from the bottom to the top of
4656the domain.<br>
4657
4658
4659
4660
4661 <br>
4662
4663
4664
4665
4666
4667The horizontal range of the smoothing is controlled by <a href="#outflow_damping_width">outflow_damping_width</a>
4668which defines the number of gridpoints (counted from the outflow
4669boundary) from where on the smoothing is applied. Starting from that
4670point, the eddy diffusivity is linearly increased (from zero to its
4671maximum value given by <span style="font-weight: bold;">km_damp_max</span>)
4672until half of the damping range width, from where it remains constant
4673up to the outflow boundary. If at a certain grid point the eddy
4674diffusivity calculated from the flow field is larger than as described
4675above, it is used instead.<br>
4676
4677
4678
4679
4680 <br>
4681
4682
4683
4684
4685
4686The default value of <span style="font-weight: bold;">km_damp_max</span>
4687has been empirically proven to be sufficient.</td>
4688
4689
4690
4691
4692 </tr>
4693
4694
4695
4696
4697 <tr>
4698
4699
4700
4701
4702
4703      <td style="vertical-align: top;"> 
4704     
4705     
4706     
4707     
4708      <p><a name="long_filter_factor"></a><b>long_filter_factor</b></p>
4709
4710
4711
4712
4713
4714      </td>
4715
4716
4717
4718
4719 <td style="vertical-align: top;">R</td>
4720
4721
4722
4723
4724
4725      <td style="vertical-align: top;"><i>0.0</i></td>
4726
4727
4728
4729
4730
4731      <td style="vertical-align: top;"> 
4732     
4733     
4734     
4735     
4736      <p>Filter factor
4737for the so-called Long-filter.<br>
4738
4739
4740
4741
4742 </p>
4743
4744
4745
4746
4747 
4748     
4749     
4750     
4751     
4752      <p><br>
4753
4754
4755
4756
4757
4758This filter very efficiently
4759eliminates 2-delta-waves sometimes cauesed by the upstream-spline
4760scheme (see Mahrer and
4761Pielke, 1978: Mon. Wea. Rev., 106, 818-830). It works in all three
4762directions in space. A value of <b>long_filter_factor</b>
4763= <i>0.01</i>
4764sufficiently removes the small-scale waves without affecting the
4765longer waves.<br>
4766
4767
4768
4769
4770 </p>
4771
4772
4773
4774
4775 
4776     
4777     
4778     
4779     
4780      <p>By default, the filter is
4781switched off (= <i>0.0</i>).
4782It is exclusively applied to the tendencies calculated by the
4783upstream-spline scheme (see <a href="#momentum_advec">momentum_advec</a>
4784and <a href="#scalar_advec">scalar_advec</a>),
4785not to the prognostic variables themselves. At the bottom and top
4786boundary of the model domain the filter effect for vertical
47872-delta-waves is reduced. There, the amplitude of these waves is only
4788reduced by approx. 50%, otherwise by nearly 100%.&nbsp; <br>
4789
4790
4791
4792
4793
4794Filter factors with values &gt; <i>0.01</i> also
4795reduce the amplitudes
4796of waves with wavelengths longer than 2-delta (see the paper by Mahrer
4797and
4798Pielke, quoted above). </p>
4799
4800
4801
4802
4803 </td>
4804
4805
4806
4807
4808 </tr>
4809
4810
4811
4812
4813 <tr>
4814
4815
4816
4817
4818      <td style="vertical-align: top;"><a name="loop_optimization"></a><span style="font-weight: bold;">loop_optimization</span></td>
4819
4820
4821
4822
4823      <td style="vertical-align: top;">C*16</td>
4824
4825
4826
4827
4828      <td style="vertical-align: top;"><span style="font-style: italic;">see right</span></td>
4829
4830
4831
4832
4833      <td>Method used to optimize loops for solving the prognostic equations .<br>
4834
4835
4836
4837
4838      <br>
4839
4840
4841
4842
4843By
4844default, the optimization method depends on the host on which PALM is
4845running. On machines with vector-type CPUs, single 3d-loops are used to
4846calculate each tendency term of each prognostic equation, while on all
4847other machines, all prognostic equations are solved within one big loop
4848over 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>
4849
4850
4851
4852
4853      <br>
4854
4855
4856
4857
4858The 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>
4859
4860
4861
4862
4863    </tr>
4864
4865
4866
4867
4868    <tr>
4869
4870
4871
4872
4873
4874      <td style="vertical-align: top;"><a name="mixing_length_1d"></a><span style="font-weight: bold;">mixing_length_1d</span><br>
4875
4876
4877
4878
4879
4880      </td>
4881
4882
4883
4884
4885 <td style="vertical-align: top;">C*20<br>
4886
4887
4888
4889
4890
4891      </td>
4892
4893
4894
4895
4896 <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
4897
4898
4899
4900
4901 <span style="font-style: italic;">model'</span><br>
4902
4903
4904
4905
4906 </td>
4907
4908
4909
4910
4911
4912      <td style="vertical-align: top;">Mixing length used in the
49131d-model.<br>
4914
4915
4916
4917
4918 <br>
4919
4920
4921
4922
4923
4924By default the mixing length is calculated as in the 3d-model (i.e. it
4925depends on the grid spacing).<br>
4926
4927
4928
4929
4930 <br>
4931
4932
4933
4934
4935
4936By setting <span style="font-weight: bold;">mixing_length_1d</span>
4937= <span style="font-style: italic;">'blackadar'</span>,
4938the so-called Blackadar mixing length is used (l = kappa * z / ( 1 +
4939kappa * z / lambda ) with the limiting value lambda = 2.7E-4 * u_g / f).<br>
4940
4941
4942
4943
4944
4945      </td>
4946
4947
4948
4949
4950 </tr>
4951
4952
4953
4954
4955 <tr>
4956
4957
4958
4959
4960 <td style="vertical-align: top;"> 
4961     
4962     
4963     
4964     
4965      <p><a name="humidity"></a><b>humidity</b></p>
4966
4967
4968
4969
4970
4971      </td>
4972
4973
4974
4975
4976 <td style="vertical-align: top;">L</td>
4977
4978
4979
4980
4981
4982      <td style="vertical-align: top;"><i>.F.</i></td>
4983
4984
4985
4986
4987
4988      <td style="vertical-align: top;"> 
4989     
4990     
4991     
4992     
4993      <p>Parameter to
4994switch on the prognostic equation for specific
4995humidity q.<br>
4996
4997
4998
4999
5000 </p>
5001
5002
5003
5004
5005 
5006     
5007     
5008     
5009     
5010      <p>The initial vertical
5011profile 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>
5012and <a href="chapter_4.1.html#q_vertical_gradient_level">q_vertical_gradient_level</a>.&nbsp;
5013Boundary conditions can be set via <a href="chapter_4.1.html#q_surface_initial_change">q_surface_initial_change</a>
5014and <a href="chapter_4.1.html#surface_waterflux">surface_waterflux</a>.<br>
5015
5016
5017
5018
5019
5020      </p>
5021
5022
5023
5024
5025
5026If the condensation scheme is switched on (<a href="chapter_4.1.html#cloud_physics">cloud_physics</a>
5027= .TRUE.), q becomes the total liquid water content (sum of specific
5028humidity and liquid water content).</td>
5029
5030
5031
5032
5033 </tr>
5034
5035
5036
5037
5038
5039    <tr>
5040
5041
5042
5043
5044 <td style="vertical-align: top;"> 
5045     
5046     
5047     
5048     
5049      <p><a name="momentum_advec"></a><b>momentum_advec</b></p>
5050
5051
5052
5053
5054
5055      </td>
5056
5057
5058
5059
5060 <td style="vertical-align: top;">C * 10</td>
5061
5062
5063
5064
5065
5066      <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
5067
5068
5069
5070
5071
5072      <td style="vertical-align: top;"> 
5073     
5074     
5075     
5076     
5077      <p>Advection
5078scheme to be used for the momentum equations.<br>
5079
5080
5081
5082
5083 <br>
5084
5085
5086
5087
5088
5089The user can choose between the following schemes:<br>
5090
5091
5092
5093
5094
5095&nbsp;<br>
5096
5097
5098
5099
5100 <br>
5101
5102
5103
5104
5105 <span style="font-style: italic;">'pw-scheme'</span><br>
5106
5107
5108
5109
5110
5111      </p>
5112
5113
5114
5115
5116 
5117     
5118     
5119     
5120     
5121      <div style="margin-left: 40px;">The scheme of
5122Piascek and
5123Williams (1970, J. Comp. Phys., 6,
5124392-405) with central differences in the form C3 is used.<br>
5125
5126
5127
5128
5129
5130If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
5131= <span style="font-style: italic;">'leapfrog+euler'</span>
5132the
5133advection scheme is - for the Euler-timestep - automatically switched
5134to an upstream-scheme.<br>
5135
5136
5137
5138
5139 </div>
5140
5141
5142
5143
5144 
5145     
5146     
5147     
5148     
5149      <p> </p>
5150
5151
5152
5153
5154 
5155     
5156     
5157     
5158     
5159      <p><span style="font-style: italic;">'ups-scheme'</span><br>
5160
5161
5162
5163
5164
5165      </p>
5166
5167
5168
5169
5170 
5171     
5172     
5173     
5174     
5175      <div style="margin-left: 40px;">The
5176upstream-spline scheme is
5177used
5178(see Mahrer and Pielke,
51791978: Mon. Wea. Rev., 106, 818-830). In opposite to the
5180Piascek-Williams scheme, this is characterized by much better numerical
5181features (less numerical diffusion, better preservation of flow
5182structures, e.g. vortices), but computationally it is much more
5183expensive. In
5184addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
5185= <span style="font-style: italic;">'</span><i>euler'</i>),
5186i.e. the
5187timestep accuracy is only of first order.
5188For this reason the advection of scalar variables (see <a href="#scalar_advec">scalar_advec</a>)
5189should then also be carried out with the upstream-spline scheme,
5190because otherwise the scalar variables would
5191be subject to large numerical diffusion due to the upstream
5192scheme.&nbsp; </div>
5193
5194
5195
5196
5197 
5198     
5199     
5200     
5201     
5202      <p style="margin-left: 40px;">Since
5203the cubic splines used tend
5204to overshoot under
5205certain circumstances, this effect must be adjusted by suitable
5206filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
5207      <a href="#long_filter_factor">long_filter_factor</a>,
5208      <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>).
5209This is always neccessary for runs with stable stratification,
5210even if this stratification appears only in parts of the model domain.<br>
5211
5212
5213
5214
5215
5216      </p>
5217
5218
5219
5220
5221 
5222     
5223     
5224     
5225     
5226      <div style="margin-left: 40px;">With stable
5227stratification the
5228upstream-spline scheme also
5229produces gravity waves with large amplitude, which must be
5230suitably damped (see <a href="chapter_4.2.html#rayleigh_damping_factor">rayleigh_damping_factor</a>).<br>
5231
5232
5233
5234
5235
5236      <br>
5237
5238
5239
5240
5241 <span style="font-weight: bold;">Important: </span>The&nbsp;
5242upstream-spline scheme is not implemented for humidity and passive
5243scalars (see&nbsp;<a href="#humidity">humidity</a>
5244and <a href="#passive_scalar">passive_scalar</a>)
5245and requires the use of a 2d-domain-decomposition. The last conditions
5246severely restricts code optimization on several machines leading to
5247very long execution times! The scheme is also not allowed for
5248non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
5249and <a href="#bc_ns">bc_ns</a>).</div>
5250
5251
5252
5253
5254 </td>
5255
5256
5257
5258
5259
5260    </tr>
5261
5262
5263
5264
5265 <tr>
5266
5267
5268
5269
5270 <td style="vertical-align: top;"><a name="netcdf_precision"></a><span style="font-weight: bold;">netcdf_precision</span><br>
5271
5272
5273
5274
5275
5276      </td>
5277
5278
5279
5280
5281 <td style="vertical-align: top;">C*20<br>
5282
5283
5284
5285
5286
5287(10)<br>
5288
5289
5290
5291
5292 </td>
5293
5294
5295
5296
5297 <td style="vertical-align: top;"><span style="font-style: italic;">single preci-</span><br style="font-style: italic;">
5298
5299
5300
5301
5302 <span style="font-style: italic;">sion for all</span><br style="font-style: italic;">
5303
5304
5305
5306
5307 <span style="font-style: italic;">output quan-</span><br style="font-style: italic;">
5308
5309
5310
5311
5312 <span style="font-style: italic;">tities</span><br>
5313
5314
5315
5316
5317 </td>
5318
5319
5320
5321
5322
5323      <td style="vertical-align: top;">Defines the accuracy of
5324the NetCDF output.<br>
5325
5326
5327
5328
5329 <br>
5330
5331
5332
5333
5334
5335By default, all NetCDF output data (see <a href="chapter_4.2.html#data_output_format">data_output_format</a>)
5336have single precision&nbsp; (4 byte) accuracy. Double precision (8
5337byte) can be choosen alternatively.<br>
5338
5339
5340
5341
5342
5343Accuracy for the different output data (cross sections, 3d-volume data,
5344spectra, etc.) can be set independently.<br>
5345
5346
5347
5348
5349 <span style="font-style: italic;">'&lt;out&gt;_NF90_REAL4'</span>
5350(single precision) or <span style="font-style: italic;">'&lt;out&gt;_NF90_REAL8'</span>
5351(double precision) are the two principally allowed values for <span style="font-weight: bold;">netcdf_precision</span>,
5352where the string <span style="font-style: italic;">'&lt;out&gt;'
5353      </span>can be chosen out of the following list:<br>
5354
5355
5356
5357
5358 <br>
5359
5360
5361
5362
5363
5364     
5365     
5366     
5367     
5368      <table style="text-align: left; width: 284px; height: 234px;" border="1" cellpadding="2" cellspacing="2">
5369
5370
5371
5372
5373 <tbody>
5374
5375
5376
5377
5378
5379          <tr>
5380
5381
5382
5383
5384 <td style="vertical-align: top;"><span style="font-style: italic;">'xy'</span><br>
5385
5386
5387
5388
5389 </td>
5390
5391
5392
5393
5394
5395            <td style="vertical-align: top;">horizontal cross section<br>
5396
5397
5398
5399
5400
5401            </td>
5402
5403
5404
5405
5406 </tr>
5407
5408
5409
5410
5411 <tr>
5412
5413
5414
5415
5416 <td style="vertical-align: top;"><span style="font-style: italic;">'xz'</span><br>
5417
5418
5419
5420
5421 </td>
5422
5423
5424
5425
5426
5427            <td style="vertical-align: top;">vertical (xz) cross
5428section<br>
5429
5430
5431
5432
5433 </td>
5434
5435
5436
5437
5438 </tr>
5439
5440
5441
5442
5443 <tr>
5444
5445
5446
5447
5448 <td style="vertical-align: top;"><span style="font-style: italic;">'yz'</span><br>
5449
5450
5451
5452
5453 </td>
5454
5455
5456
5457
5458
5459            <td style="vertical-align: top;">vertical (yz) cross
5460section<br>
5461
5462
5463
5464
5465 </td>
5466
5467
5468
5469
5470 </tr>
5471
5472
5473
5474
5475 <tr>
5476
5477
5478
5479
5480 <td style="vertical-align: top;"><span style="font-style: italic;">'2d'</span><br>
5481
5482
5483
5484
5485 </td>
5486
5487
5488
5489
5490
5491            <td style="vertical-align: top;">all cross sections<br>
5492
5493
5494
5495
5496
5497            </td>
5498
5499
5500
5501
5502 </tr>
5503
5504
5505
5506
5507 <tr>
5508
5509
5510
5511
5512 <td style="vertical-align: top;"><span style="font-style: italic;">'3d'</span><br>
5513
5514
5515
5516
5517 </td>
5518
5519
5520
5521
5522
5523            <td style="vertical-align: top;">volume data<br>
5524
5525
5526
5527
5528 </td>
5529
5530
5531
5532
5533
5534          </tr>
5535
5536
5537
5538
5539 <tr>
5540
5541
5542
5543
5544 <td style="vertical-align: top;"><span style="font-style: italic;">'pr'</span><br>
5545
5546
5547
5548
5549 </td>
5550
5551
5552
5553
5554
5555            <td style="vertical-align: top;">vertical profiles<br>
5556
5557
5558
5559
5560
5561            </td>
5562
5563
5564
5565
5566 </tr>
5567
5568
5569
5570
5571 <tr>
5572
5573
5574
5575
5576 <td style="vertical-align: top;"><span style="font-style: italic;">'ts'</span><br>
5577
5578
5579
5580
5581 </td>
5582
5583
5584
5585
5586
5587            <td style="vertical-align: top;">time series, particle
5588time series<br>
5589
5590
5591
5592
5593 </td>
5594
5595
5596
5597
5598 </tr>
5599
5600
5601
5602
5603 <tr>
5604
5605
5606
5607
5608 <td style="vertical-align: top;"><span style="font-style: italic;">'sp'</span><br>
5609
5610
5611
5612
5613 </td>
5614
5615
5616
5617
5618
5619            <td style="vertical-align: top;">spectra<br>
5620
5621
5622
5623
5624 </td>
5625
5626
5627
5628
5629
5630          </tr>
5631
5632
5633
5634
5635 <tr>
5636
5637
5638
5639
5640 <td style="vertical-align: top;"><span style="font-style: italic;">'prt'</span><br>
5641
5642
5643
5644
5645 </td>
5646
5647
5648
5649
5650
5651            <td style="vertical-align: top;">particles<br>
5652
5653
5654
5655
5656 </td>
5657
5658
5659
5660
5661
5662          </tr>
5663
5664
5665
5666
5667 <tr>
5668
5669
5670
5671
5672 <td style="vertical-align: top;"><span style="font-style: italic;">'all'</span><br>
5673
5674
5675
5676
5677 </td>
5678
5679
5680
5681
5682
5683            <td style="vertical-align: top;">all output quantities<br>
5684
5685
5686
5687
5688
5689            </td>
5690
5691
5692
5693
5694 </tr>
5695
5696
5697
5698
5699 
5700       
5701       
5702       
5703       
5704        </tbody> 
5705     
5706     
5707     
5708     
5709      </table>
5710
5711
5712
5713
5714 <br>
5715
5716
5717
5718
5719 <span style="font-weight: bold;">Example:</span><br>
5720
5721
5722
5723
5724
5725If all cross section data and the particle data shall be output in
5726double 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>
5727has to be assigned.<br>
5728
5729
5730
5731
5732 </td>
5733
5734
5735
5736
5737 </tr>
5738
5739
5740
5741
5742
5743    <tr>
5744
5745
5746
5747
5748 <td style="vertical-align: top;"> 
5749     
5750     
5751     
5752     
5753      <p><a name="npex"></a><b>npex</b></p>
5754
5755
5756
5757
5758 </td>
5759
5760
5761
5762
5763
5764      <td style="vertical-align: top;">I</td>
5765
5766
5767
5768
5769 <td style="vertical-align: top;"><br>
5770
5771
5772
5773
5774 </td>
5775
5776
5777
5778
5779 <td style="vertical-align: top;"> 
5780     
5781     
5782     
5783     
5784      <p>Number of processors
5785along x-direction of the virtual
5786processor
5787net.&nbsp; </p>
5788
5789
5790
5791
5792 
5793     
5794     
5795     
5796     
5797      <p>For parallel runs, the total
5798number of processors to be used
5799is given by
5800the <span style="font-weight: bold;">mrun</span>
5801option <a href="http://www.muk.uni-hannover.de/software/mrun_beschreibung.html#Opt-X">-X</a>.
5802By default, depending on the type of the parallel computer, PALM
5803generates a 1d processor
5804net (domain decomposition along x, <span style="font-weight: bold;">npey</span>
5805= <span style="font-style: italic;">1</span>) or a
58062d-net (this is
5807favored on machines with fast communication network). In case of a
58082d-net, it is tried to make it more or less square-shaped. If, for
5809example, 16 processors are assigned (-X 16), a 4 * 4 processor net is
5810generated (<span style="font-weight: bold;">npex</span>
5811= <span style="font-style: italic;">4</span>, <span style="font-weight: bold;">npey</span>
5812= <span style="font-style: italic;">4</span>).
5813This choice is optimal for square total domains (<a href="#nx">nx</a>
5814= <a href="#ny">ny</a>),
5815since then the number of ghost points at the lateral boundarys of
5816the subdomains is minimal. If <span style="font-weight: bold;">nx</span>
5817nd <span style="font-weight: bold;">ny</span>
5818differ extremely, the
5819processor 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>
5820
5821
5822
5823
5824
5825     
5826     
5827     
5828     
5829      <p><b>Important:</b> The value of <span style="font-weight: bold;">npex</span> * <span style="font-weight: bold;">npey</span> must exactly
5830correspond to the
5831value assigned by the <span style="font-weight: bold;">mrun</span>-option
5832      <tt>-X</tt>.
5833Otherwise the model run will abort with a corresponding error
5834message.&nbsp; <br>
5835
5836
5837
5838
5839
5840Additionally, the specification of <span style="font-weight: bold;">npex</span>
5841and <span style="font-weight: bold;">npey</span>
5842may of course
5843override the default setting for the domain decomposition (1d or 2d)
5844which may have a significant (negative) effect on the code performance.
5845      </p>
5846
5847
5848
5849
5850 </td>
5851
5852
5853
5854
5855 </tr>
5856
5857
5858
5859
5860 <tr>
5861
5862
5863
5864
5865 <td style="vertical-align: top;"> 
5866     
5867     
5868     
5869     
5870      <p><a name="npey"></a><b>npey</b></p>
5871
5872
5873
5874
5875
5876      </td>
5877
5878
5879
5880
5881 <td style="vertical-align: top;">I</td>
5882
5883
5884
5885
5886
5887      <td style="vertical-align: top;"><br>
5888
5889
5890
5891
5892 </td>
5893
5894
5895
5896
5897 <td style="vertical-align: top;"> 
5898     
5899     
5900     
5901     
5902      <p>Number of processors
5903along y-direction of the virtual
5904processor
5905net.&nbsp; </p>
5906
5907
5908
5909
5910 
5911     
5912     
5913     
5914     
5915      <p>For further information see <a href="#npex">npex</a>.</p>
5916
5917
5918
5919
5920 </td>
5921
5922
5923
5924
5925 </tr>
5926
5927
5928
5929
5930
5931    <tr>
5932
5933
5934
5935
5936 <td style="vertical-align: top;"> 
5937     
5938     
5939     
5940     
5941      <p><a name="nsor_ini"></a><b>nsor_ini</b></p>
5942
5943
5944
5945
5946
5947      </td>
5948
5949
5950
5951
5952 <td style="vertical-align: top;">I</td>
5953
5954
5955
5956
5957
5958      <td style="vertical-align: top;"><i>100</i></td>
5959
5960
5961
5962
5963
5964      <td style="vertical-align: top;"> 
5965     
5966     
5967     
5968     
5969      <p>Initial number
5970of iterations with the SOR algorithm.&nbsp; </p>
5971
5972
5973
5974
5975 
5976     
5977     
5978     
5979     
5980      <p>This
5981parameter is only effective if the SOR algorithm was
5982selected as the pressure solver scheme (<a href="chapter_4.2.html#psolver">psolver</a>
5983= <span style="font-style: italic;">'sor'</span>)
5984and specifies the
5985number of initial iterations of the SOR
5986scheme (at t = 0). The number of subsequent iterations at the following
5987timesteps is determined
5988with the parameter <a href="#nsor">nsor</a>.
5989Usually <b>nsor</b> &lt; <b>nsor_ini</b>,
5990since in each case
5991subsequent calls to <a href="chapter_4.2.html#psolver">psolver</a>
5992use the solution of the previous call as initial value. Suitable
5993test runs should determine whether sufficient convergence of the
5994solution is obtained with the default value and if necessary the value
5995of <b>nsor_ini</b> should be changed.</p>
5996
5997
5998
5999
6000 </td>
6001
6002
6003
6004
6005
6006    </tr>
6007
6008
6009
6010
6011 <tr>
6012
6013
6014
6015
6016 <td style="vertical-align: top;">
6017     
6018     
6019     
6020     
6021      <p><a name="nx"></a><b>nx</b></p>
6022
6023
6024
6025
6026
6027      </td>
6028
6029
6030
6031
6032 <td style="vertical-align: top;">I</td>
6033
6034
6035
6036
6037
6038      <td style="vertical-align: top;"><br>
6039
6040
6041
6042
6043 </td>
6044
6045
6046
6047
6048 <td style="vertical-align: top;"> 
6049     
6050     
6051     
6052     
6053      <p>Number of grid
6054points in x-direction.&nbsp; </p>
6055
6056
6057
6058
6059 
6060     
6061     
6062     
6063     
6064      <p>A value for this
6065parameter must be assigned. Since the lower
6066array bound in PALM
6067starts with i = 0, the actual number of grid points is equal to <b>nx+1</b>.
6068In case of cyclic boundary conditions along x, the domain size is (<b>nx+1</b>)*
6069      <a href="#dx">dx</a>.</p>
6070
6071
6072
6073
6074 
6075     
6076     
6077     
6078     
6079      <p>For
6080parallel runs, in case of <a href="#grid_matching">grid_matching</a>
6081= <span style="font-style: italic;">'strict'</span>,
6082      <b>nx+1</b> must
6083be an integral multiple
6084of the processor numbers (see <a href="#npex">npex</a>
6085and <a href="#npey">npey</a>)
6086along x- as well as along y-direction (due to data
6087transposition restrictions).</p>
6088
6089
6090
6091
6092     
6093     
6094     
6095     
6096      <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>
6097and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
6098
6099
6100
6101
6102 </td>
6103
6104
6105
6106
6107 </tr>
6108
6109
6110
6111
6112 <tr>
6113
6114
6115
6116
6117
6118      <td style="vertical-align: top;"> 
6119     
6120     
6121     
6122     
6123      <p><a name="ny"></a><b>ny</b></p>
6124
6125
6126
6127
6128
6129      </td>
6130
6131
6132
6133
6134 <td style="vertical-align: top;">I</td>
6135
6136
6137
6138
6139
6140      <td style="vertical-align: top;"><br>
6141
6142
6143
6144
6145 </td>
6146
6147
6148
6149
6150 <td style="vertical-align: top;"> 
6151     
6152     
6153     
6154     
6155      <p>Number of grid
6156points in y-direction.&nbsp; </p>
6157
6158
6159
6160
6161 
6162     
6163     
6164     
6165     
6166      <p>A value for this
6167parameter must be assigned. Since the lower
6168array bound in PALM starts with j = 0, the actual number of grid points
6169is equal to <b>ny+1</b>. In case of cyclic boundary
6170conditions along
6171y, the domain size is (<b>ny+1</b>) * <a href="#dy">dy</a>.</p>
6172
6173
6174
6175
6176
6177     
6178     
6179     
6180     
6181      <p>For parallel runs, in case of <a href="#grid_matching">grid_matching</a>
6182= <span style="font-style: italic;">'strict'</span>,
6183      <b>ny+1</b> must
6184be an integral multiple
6185of the processor numbers (see <a href="#npex">npex</a>
6186and <a href="#npey">npey</a>)&nbsp;
6187along y- as well as along x-direction (due to data
6188transposition restrictions).</p>
6189
6190
6191
6192
6193     
6194     
6195     
6196     
6197      <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>
6198and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
6199
6200
6201
6202
6203 </td>
6204
6205
6206
6207
6208 </tr>
6209
6210
6211
6212
6213 <tr>
6214
6215
6216
6217
6218
6219      <td style="vertical-align: top;"> 
6220     
6221     
6222     
6223     
6224      <p><a name="nz"></a><b>nz</b></p>
6225
6226
6227
6228
6229
6230      </td>
6231
6232
6233
6234
6235 <td style="vertical-align: top;">I</td>
6236
6237
6238
6239
6240
6241      <td style="vertical-align: top;"><br>
6242
6243
6244
6245
6246 </td>
6247
6248
6249
6250
6251 <td style="vertical-align: top;"> 
6252     
6253     
6254     
6255     
6256      <p>Number of grid
6257points in z-direction.&nbsp; </p>
6258
6259
6260
6261
6262 
6263     
6264     
6265     
6266     
6267      <p>A value for this
6268parameter must be assigned. Since the lower
6269array bound in PALM
6270starts with k = 0 and since one additional grid point is added at the
6271top boundary (k = <b>nz+1</b>), the actual number of grid
6272points is <b>nz+2</b>.
6273However, the prognostic equations are only solved up to <b>nz</b>
6274(u,
6275v)
6276or up to <b>nz-1</b> (w, scalar quantities). The top
6277boundary for u
6278and v is at k = <b>nz+1</b> (u, v) while at k = <b>nz</b>
6279for all
6280other quantities.&nbsp; </p>
6281
6282
6283
6284
6285 
6286     
6287     
6288     
6289     
6290      <p>For parallel
6291runs,&nbsp; in case of <a href="#grid_matching">grid_matching</a>
6292= <span style="font-style: italic;">'strict'</span>,
6293      <b>nz</b> must
6294be an integral multiple of
6295the number of processors in x-direction (due to data transposition
6296restrictions).</p>
6297
6298
6299
6300
6301 </td>
6302
6303
6304
6305
6306 </tr>
6307
6308
6309
6310
6311 <tr>
6312
6313
6314
6315
6316      <td style="vertical-align: top;"><a name="ocean"></a><span style="font-weight: bold;">ocean</span></td>
6317
6318
6319
6320
6321      <td style="vertical-align: top;">L</td>
6322
6323
6324
6325
6326      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
6327
6328
6329
6330
6331      <td style="vertical-align: top;">Parameter to switch on&nbsp;ocean runs.<br>
6332
6333
6334
6335
6336      <br>
6337
6338
6339
6340
6341By 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>
6342
6343
6344
6345
6346      <br>
6347
6348
6349
6350
6351     
6352     
6353     
6354     
6355      <ul>
6356
6357
6358
6359
6360        <li>An additional prognostic equation for salinity is solved.</li>
6361
6362
6363
6364
6365        <li>Potential temperature in buoyancy and stability-related terms is replaced by potential density.</li>
6366
6367
6368
6369
6370        <li>Potential
6371density is calculated from the equation of state for seawater after
6372each timestep, using the algorithm proposed by Jackett et al. (2006, J.
6373Atmos. Oceanic Technol., <span style="font-weight: bold;">23</span>, 1709-1728).<br>
6374
6375
6376
6377
6378So far, only the initial hydrostatic pressure is entered into this equation.</li>
6379
6380
6381
6382
6383        <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>
6384
6385
6386
6387
6388        <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>
6389
6390
6391
6392
6393        <li>Zero salinity flux is used as default boundary condition at the bottom of the sea.</li>
6394
6395
6396
6397
6398        <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>
6399
6400
6401
6402
6403     
6404     
6405     
6406     
6407      </ul>
6408
6409
6410
6411
6412      <br>
6413
6414
6415
6416
6417Relevant 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>
6418
6419
6420
6421
6422      <br>
6423
6424
6425
6426
6427Section <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>
6428
6429
6430
6431
6432      <br>
6433
6434
6435
6436
6437      <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>
6438
6439      </td>
6440
6441
6442
6443
6444    </tr>
6445
6446
6447
6448
6449    <tr>
6450
6451
6452
6453
6454 <td style="vertical-align: top;"> 
6455     
6456     
6457     
6458     
6459      <p><a name="omega"></a><b>omega</b></p>
6460
6461
6462
6463
6464
6465      </td>
6466
6467
6468
6469
6470 <td style="vertical-align: top;">R</td>
6471
6472
6473
6474
6475
6476      <td style="vertical-align: top;"><i>7.29212E-5</i></td>
6477
6478
6479
6480
6481
6482      <td style="vertical-align: top;"> 
6483     
6484     
6485     
6486     
6487      <p>Angular
6488velocity of the rotating system (in rad s<sup>-1</sup>).&nbsp;
6489      </p>
6490
6491
6492
6493
6494 
6495     
6496     
6497     
6498     
6499      <p>The angular velocity of the earth is set by
6500default. The
6501values
6502of the Coriolis parameters are calculated as:&nbsp; </p>
6503
6504
6505
6506
6507 
6508     
6509     
6510     
6511     
6512      <ul>
6513
6514
6515
6516
6517
6518       
6519       
6520       
6521       
6522        <p>f = 2.0 * <b>omega</b> * sin(<a href="#phi">phi</a>)&nbsp;
6523        <br>
6524
6525
6526
6527
6528f* = 2.0 * <b>omega</b> * cos(<a href="#phi">phi</a>)</p>
6529
6530
6531
6532
6533
6534     
6535     
6536     
6537     
6538      </ul>
6539
6540
6541
6542
6543 </td>
6544
6545
6546
6547
6548 </tr>
6549
6550
6551
6552
6553 <tr>
6554
6555
6556
6557
6558 <td style="vertical-align: top;"> 
6559     
6560     
6561     
6562     
6563      <p><a name="outflow_damping_width"></a><b>outflow_damping_width</b></p>
6564
6565
6566
6567
6568
6569      </td>
6570
6571
6572
6573
6574 <td style="vertical-align: top;">I</td>
6575
6576
6577
6578
6579
6580      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(20,
6581nx/2</span> or <span style="font-style: italic;">ny/2)</span></td>
6582
6583
6584
6585
6586
6587      <td style="vertical-align: top;">Width of
6588the damping range in the vicinity of the outflow (gridpoints).<br>
6589
6590
6591
6592
6593
6594      <br>
6595
6596
6597
6598
6599
6600When using non-cyclic lateral boundaries (see <a href="chapter_4.1.html#bc_lr">bc_lr</a>
6601or <a href="chapter_4.1.html#bc_ns">bc_ns</a>),
6602a smoothing has to be applied to the
6603velocity field in the vicinity of the outflow in order to suppress any
6604reflections of outgoing disturbances. This parameter controlls the
6605horizontal range to which the smoothing is applied. The range is given
6606in gridpoints counted from the respective outflow boundary. For further
6607details about the smoothing see parameter <a href="chapter_4.1.html#km_damp_max">km_damp_max</a>,
6608which defines the magnitude of the damping.</td>
6609
6610
6611
6612
6613 </tr>
6614
6615
6616
6617
6618
6619    <tr>
6620
6621
6622
6623
6624 <td style="vertical-align: top;"> 
6625     
6626     
6627     
6628     
6629      <p><a name="overshoot_limit_e"></a><b>overshoot_limit_e</b></p>
6630
6631
6632
6633
6634
6635      </td>
6636
6637
6638
6639
6640 <td style="vertical-align: top;">R</td>
6641
6642
6643
6644
6645
6646      <td style="vertical-align: top;"><i>0.0</i></td>
6647
6648
6649
6650
6651
6652      <td style="vertical-align: top;"> 
6653     
6654     
6655     
6656     
6657      <p>Allowed limit
6658for the overshooting of subgrid-scale TKE in
6659case that the upstream-spline scheme is switched on (in m<sup>2</sup>/s<sup>2</sup>).&nbsp;
6660      </p>
6661
6662
6663
6664
6665 
6666     
6667     
6668     
6669     
6670      <p>By deafult, if cut-off of overshoots is switched
6671on for the
6672upstream-spline scheme (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>),
6673no overshoots are permitted at all. If <b>overshoot_limit_e</b>
6674is given a non-zero value, overshoots with the respective
6675amplitude (both upward and downward) are allowed.&nbsp; </p>
6676
6677
6678
6679
6680
6681     
6682     
6683     
6684     
6685      <p>Only positive values are allowed for <b>overshoot_limit_e</b>.</p>
6686
6687
6688
6689
6690
6691      </td>
6692
6693
6694
6695
6696 </tr>
6697
6698
6699
6700
6701 <tr>
6702
6703
6704
6705
6706 <td style="vertical-align: top;"> 
6707     
6708     
6709     
6710     
6711      <p><a name="overshoot_limit_pt"></a><b>overshoot_limit_pt</b></p>
6712
6713
6714
6715
6716
6717      </td>
6718
6719
6720
6721
6722 <td style="vertical-align: top;">R</td>
6723
6724
6725
6726
6727
6728      <td style="vertical-align: top;"><i>0.0</i></td>
6729
6730
6731
6732
6733
6734      <td style="vertical-align: top;"> 
6735     
6736     
6737     
6738     
6739      <p>Allowed limit
6740for the overshooting of potential temperature in
6741case that the upstream-spline scheme is switched on (in K).&nbsp; </p>
6742
6743
6744
6745
6746
6747     
6748     
6749     
6750     
6751      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6752      </p>
6753
6754
6755
6756
6757 
6758     
6759     
6760     
6761     
6762      <p>Only positive values are allowed for <b>overshoot_limit_pt</b>.</p>
6763
6764
6765
6766
6767
6768      </td>
6769
6770
6771
6772
6773 </tr>
6774
6775
6776
6777
6778 <tr>
6779
6780
6781
6782
6783 <td style="vertical-align: top;"> 
6784     
6785     
6786     
6787     
6788      <p><a name="overshoot_limit_u"></a><b>overshoot_limit_u</b></p>
6789
6790
6791
6792
6793
6794      </td>
6795
6796
6797
6798
6799 <td style="vertical-align: top;">R</td>
6800
6801
6802
6803
6804
6805      <td style="vertical-align: top;"><i>0.0</i></td>
6806
6807
6808
6809
6810
6811      <td style="vertical-align: top;">Allowed limit for the
6812overshooting of
6813the u-component of velocity in case that the upstream-spline scheme is
6814switched on (in m/s).
6815     
6816     
6817     
6818     
6819      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6820      </p>
6821
6822
6823
6824
6825 
6826     
6827     
6828     
6829     
6830      <p>Only positive values are allowed for <b>overshoot_limit_u</b>.</p>
6831
6832
6833
6834
6835
6836      </td>
6837
6838
6839
6840
6841 </tr>
6842
6843
6844
6845
6846 <tr>
6847
6848
6849
6850
6851 <td style="vertical-align: top;"> 
6852     
6853     
6854     
6855     
6856      <p><a name="overshoot_limit_v"></a><b>overshoot_limit_v</b></p>
6857
6858
6859
6860
6861
6862      </td>
6863
6864
6865
6866
6867 <td style="vertical-align: top;">R</td>
6868
6869
6870
6871
6872
6873      <td style="vertical-align: top;"><i>0.0</i></td>
6874
6875
6876
6877
6878
6879      <td style="vertical-align: top;"> 
6880     
6881     
6882     
6883     
6884      <p>Allowed limit
6885for the overshooting of the v-component of
6886velocity in case that the upstream-spline scheme is switched on
6887(in m/s).&nbsp; </p>
6888
6889
6890
6891
6892 
6893     
6894     
6895     
6896     
6897      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6898      </p>
6899
6900
6901
6902
6903 
6904     
6905     
6906     
6907     
6908      <p>Only positive values are allowed for <b>overshoot_limit_v</b>.</p>
6909
6910
6911
6912
6913
6914      </td>
6915
6916
6917
6918
6919 </tr>
6920
6921
6922
6923
6924 <tr>
6925
6926
6927
6928
6929 <td style="vertical-align: top;"> 
6930     
6931     
6932     
6933     
6934      <p><a name="overshoot_limit_w"></a><b>overshoot_limit_w</b></p>
6935
6936
6937
6938
6939
6940      </td>
6941
6942
6943
6944
6945 <td style="vertical-align: top;">R</td>
6946
6947
6948
6949
6950
6951      <td style="vertical-align: top;"><i>0.0</i></td>
6952
6953
6954
6955
6956
6957      <td style="vertical-align: top;"> 
6958     
6959     
6960     
6961     
6962      <p>Allowed limit
6963for the overshooting of the w-component of
6964velocity in case that the upstream-spline scheme is switched on
6965(in m/s).&nbsp; </p>
6966
6967
6968
6969
6970 
6971     
6972     
6973     
6974     
6975      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6976      </p>
6977
6978
6979
6980
6981 
6982     
6983     
6984     
6985     
6986      <p>Only positive values are permitted for <b>overshoot_limit_w</b>.</p>
6987
6988
6989
6990
6991
6992      </td>
6993
6994
6995
6996
6997 </tr>
6998
6999
7000
7001
7002 <tr>
7003
7004
7005
7006
7007 <td style="vertical-align: top;"> 
7008     
7009     
7010     
7011     
7012      <p><a name="passive_scalar"></a><b>passive_scalar</b></p>
7013
7014
7015
7016
7017
7018      </td>
7019
7020
7021
7022
7023 <td style="vertical-align: top;">L</td>
7024
7025
7026
7027
7028
7029      <td style="vertical-align: top;"><i>.F.</i></td>
7030
7031
7032
7033
7034
7035      <td style="vertical-align: top;"> 
7036     
7037     
7038     
7039     
7040      <p>Parameter to
7041switch on the prognostic equation for a passive
7042scalar. <br>
7043
7044
7045
7046
7047 </p>
7048
7049
7050
7051
7052 
7053     
7054     
7055     
7056     
7057      <p>The initial vertical profile
7058of s can be set via parameters <a href="#s_surface">s_surface</a>,
7059      <a href="#s_vertical_gradient">s_vertical_gradient</a>
7060and&nbsp; <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
7061Boundary conditions can be set via <a href="#s_surface_initial_change">s_surface_initial_change</a>
7062and <a href="#surface_scalarflux">surface_scalarflux</a>.&nbsp;
7063      </p>
7064
7065
7066
7067
7068 
7069     
7070     
7071     
7072     
7073      <p><b>Note:</b> <br>
7074
7075
7076
7077
7078
7079With <span style="font-weight: bold;">passive_scalar</span>
7080switched
7081on, the simultaneous use of humidity (see&nbsp;<a href="#humidity">humidity</a>)
7082is impossible.</p>
7083
7084
7085
7086
7087 </td>
7088
7089
7090
7091
7092 </tr>
7093
7094
7095
7096
7097 <tr>
7098
7099
7100
7101
7102 <td style="vertical-align: top;"> 
7103     
7104     
7105     
7106     
7107      <p><a name="phi"></a><b>phi</b></p>
7108
7109
7110
7111
7112
7113      </td>
7114
7115
7116
7117
7118 <td style="vertical-align: top;">R</td>
7119
7120
7121
7122
7123
7124      <td style="vertical-align: top;"><i>55.0</i></td>
7125
7126
7127
7128
7129
7130      <td style="vertical-align: top;"> 
7131     
7132     
7133     
7134     
7135      <p>Geographical
7136latitude (in degrees).&nbsp; </p>
7137
7138
7139
7140
7141 
7142     
7143     
7144     
7145     
7146      <p>The value of
7147this parameter determines the value of the
7148Coriolis parameters f and f*, provided that the angular velocity (see <a href="#omega">omega</a>)
7149is non-zero.</p>
7150
7151
7152
7153
7154 </td>
7155
7156
7157
7158
7159 </tr>
7160
7161
7162
7163
7164 <tr>
7165
7166
7167
7168
7169 <td style="vertical-align: top;"> 
7170     
7171     
7172     
7173     
7174      <p><a name="prandtl_layer"></a><b>prandtl_layer</b></p>
7175
7176
7177
7178
7179
7180      </td>
7181
7182
7183
7184
7185 <td style="vertical-align: top;">L</td>
7186
7187
7188
7189
7190
7191      <td style="vertical-align: top;"><i>.T.</i></td>
7192
7193
7194
7195
7196
7197      <td style="vertical-align: top;"> 
7198     
7199     
7200     
7201     
7202      <p>Parameter to
7203switch on a Prandtl layer.&nbsp; </p>
7204
7205
7206
7207
7208 
7209     
7210     
7211     
7212     
7213      <p>By default,
7214a Prandtl layer is switched on at the bottom
7215boundary between z = 0 and z = 0.5 * <a href="#dz">dz</a>
7216(the first computational grid point above ground for u, v and the
7217scalar quantities).
7218In this case, at the bottom boundary, free-slip conditions for u and v
7219(see <a href="#bc_uv_b">bc_uv_b</a>)
7220are not allowed. Likewise, laminar
7221simulations with constant eddy diffusivities (<a href="#km_constant">km_constant</a>)
7222are forbidden.&nbsp; </p>
7223
7224
7225
7226
7227 
7228     
7229     
7230     
7231     
7232      <p>With Prandtl-layer
7233switched off, the TKE boundary condition <a href="#bc_e_b">bc_e_b</a>
7234= '<i>(u*)**2+neumann'</i> must not be used and is
7235automatically
7236changed to <i>'neumann'</i> if necessary.&nbsp; Also,
7237the pressure
7238boundary condition <a href="#bc_p_b">bc_p_b</a>
7239= <i>'neumann+inhomo'</i>&nbsp; is not allowed. </p>
7240
7241
7242
7243
7244
7245     
7246     
7247     
7248     
7249      <p>The roughness length is declared via the parameter <a href="#roughness_length">roughness_length</a>.</p>
7250
7251
7252
7253
7254
7255      </td>
7256
7257
7258
7259
7260 </tr>
7261
7262
7263
7264
7265 <tr>
7266
7267
7268
7269
7270 <td style="vertical-align: top;"> 
7271     
7272     
7273     
7274     
7275      <p><a name="precipitation"></a><b>precipitation</b></p>
7276
7277
7278
7279
7280
7281      </td>
7282
7283
7284
7285
7286 <td style="vertical-align: top;">L</td>
7287
7288
7289
7290
7291
7292      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
7293
7294
7295
7296
7297 <td style="vertical-align: top;"> 
7298     
7299     
7300     
7301     
7302      <p>Parameter to switch
7303on the precipitation scheme.<br>
7304
7305
7306
7307
7308 </p>
7309
7310
7311
7312
7313 
7314     
7315     
7316     
7317     
7318      <p>For
7319precipitation processes PALM uses a simplified Kessler
7320scheme. This scheme only considers the
7321so-called autoconversion, that means the generation of rain water by
7322coagulation of cloud drops among themselves. Precipitation begins and
7323is immediately removed from the flow as soon as the liquid water
7324content exceeds the critical value of 0.5 g/kg.</p>
7325
7326
7327
7328
7329     
7330     
7331     
7332     
7333      <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>
7334
7335
7336
7337
7338 </td>
7339
7340
7341
7342
7343 </tr>
7344
7345
7346
7347
7348
7349    <tr>
7350
7351
7352
7353
7354      <td style="vertical-align: top;"><a name="pt_reference"></a><span style="font-weight: bold;">pt_reference</span></td>
7355
7356
7357
7358
7359      <td style="vertical-align: top;">R</td>
7360
7361
7362
7363
7364      <td style="vertical-align: top;"><span style="font-style: italic;">use horizontal average as
7365refrence</span></td>
7366
7367
7368
7369
7370      <td style="vertical-align: top;">Reference
7371temperature to be used in all buoyancy terms (in K).<br>
7372
7373
7374
7375
7376      <br>
7377
7378
7379
7380
7381By
7382default, the instantaneous horizontal average over the total model
7383domain is used.<br>
7384
7385
7386
7387
7388      <br>
7389
7390
7391
7392
7393      <span style="font-weight: bold;">Attention:</span><br>
7394
7395
7396
7397
7398In 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>
7399
7400
7401
7402
7403    </tr>
7404
7405
7406
7407
7408    <tr>
7409
7410
7411
7412
7413 <td style="vertical-align: top;"> 
7414     
7415     
7416     
7417     
7418      <p><a name="pt_surface"></a><b>pt_surface</b></p>
7419
7420
7421
7422
7423
7424      </td>
7425
7426
7427
7428
7429 <td style="vertical-align: top;">R</td>
7430
7431
7432
7433
7434
7435      <td style="vertical-align: top;"><i>300.0</i></td>
7436
7437
7438
7439
7440
7441      <td style="vertical-align: top;"> 
7442     
7443     
7444     
7445     
7446      <p>Surface
7447potential temperature (in K).&nbsp; </p>
7448
7449
7450
7451
7452 
7453     
7454     
7455     
7456     
7457      <p>This
7458parameter assigns the value of the potential temperature
7459      <span style="font-weight: bold;">pt</span> at the surface (k=0)<b>.</b> Starting from this value,
7460the
7461initial vertical temperature profile is constructed with <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7462and <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level
7463      </a>.
7464This profile is also used for the 1d-model as a stationary profile.</p>
7465
7466
7467
7468
7469     
7470     
7471     
7472     
7473      <p><span style="font-weight: bold;">Attention:</span><br>
7474
7475
7476
7477
7478In case of ocean runs (see <a href="#ocean">ocean</a>),
7479this parameter gives the temperature value at the sea surface, which is
7480at k=nzt. The profile is then constructed from the surface down to the
7481bottom of the model.</p>
7482
7483
7484
7485
7486
7487      </td>
7488
7489
7490
7491
7492 </tr>
7493
7494
7495
7496
7497 <tr>
7498
7499
7500
7501
7502 <td style="vertical-align: top;"> 
7503     
7504     
7505     
7506     
7507      <p><a name="pt_surface_initial_change"></a><b>pt_surface_initial</b>
7508      <br>
7509
7510
7511
7512
7513 <b>_change</b></p>
7514
7515
7516
7517
7518 </td>
7519
7520
7521
7522
7523 <td style="vertical-align: top;">R</td>
7524
7525
7526
7527
7528 <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
7529
7530
7531
7532
7533 </td>
7534
7535
7536
7537
7538
7539      <td style="vertical-align: top;"> 
7540     
7541     
7542     
7543     
7544      <p>Change in
7545surface temperature to be made at the beginning of
7546the 3d run
7547(in K).&nbsp; </p>
7548
7549
7550
7551
7552 
7553     
7554     
7555     
7556     
7557      <p>If <b>pt_surface_initial_change</b>
7558is set to a non-zero
7559value, the near surface sensible heat flux is not allowed to be given
7560simultaneously (see <a href="#surface_heatflux">surface_heatflux</a>).</p>
7561
7562
7563
7564
7565
7566      </td>
7567
7568
7569
7570
7571 </tr>
7572
7573
7574
7575
7576 <tr>
7577
7578
7579
7580
7581 <td style="vertical-align: top;"> 
7582     
7583     
7584     
7585     
7586      <p><a name="pt_vertical_gradient"></a><b>pt_vertical_gradient</b></p>
7587
7588
7589
7590
7591
7592      </td>
7593
7594
7595
7596
7597 <td style="vertical-align: top;">R (10)</td>
7598
7599
7600
7601
7602
7603      <td style="vertical-align: top;"><i>10 * 0.0</i></td>
7604
7605
7606
7607
7608
7609      <td style="vertical-align: top;"> 
7610     
7611     
7612     
7613     
7614      <p>Temperature
7615gradient(s) of the initial temperature profile (in
7616K
7617/ 100 m).&nbsp; </p>
7618
7619
7620
7621
7622 
7623     
7624     
7625     
7626     
7627      <p>This temperature gradient
7628holds starting from the height&nbsp;
7629level defined by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>
7630(precisely: for all uv levels k where zu(k) &gt;
7631pt_vertical_gradient_level,
7632pt_init(k) is set: pt_init(k) = pt_init(k-1) + dzu(k) * <b>pt_vertical_gradient</b>)
7633up to the top boundary or up to the next height level defined
7634by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>.
7635A total of 10 different gradients for 11 height intervals (10 intervals
7636if <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>(1)
7637= <i>0.0</i>) can be assigned. The surface temperature is
7638assigned via <a href="#pt_surface">pt_surface</a>.&nbsp;
7639      </p>
7640
7641
7642
7643
7644 
7645     
7646     
7647     
7648     
7649      <p>Example:&nbsp; </p>
7650
7651
7652
7653
7654 
7655     
7656     
7657     
7658     
7659      <ul>
7660
7661
7662
7663
7664 
7665       
7666       
7667       
7668       
7669        <p><b>pt_vertical_gradient</b>
7670= <i>1.0</i>, <i>0.5</i>,&nbsp; <br>
7671
7672
7673
7674
7675
7676        <b>pt_vertical_gradient_level</b> = <i>500.0</i>,
7677        <i>1000.0</i>,</p>
7678
7679
7680
7681
7682 
7683     
7684     
7685     
7686     
7687      </ul>
7688
7689
7690
7691
7692 
7693     
7694     
7695     
7696     
7697      <p>That
7698defines the temperature profile to be neutrally
7699stratified
7700up to z = 500.0 m with a temperature given by <a href="#pt_surface">pt_surface</a>.
7701For 500.0 m &lt; z &lt;= 1000.0 m the temperature gradient is
77021.0 K /
7703100 m and for z &gt; 1000.0 m up to the top boundary it is
77040.5 K / 100 m (it is assumed that the assigned height levels correspond
7705with uv levels).</p>
7706
7707
7708
7709
7710     
7711     
7712     
7713     
7714      <p><span style="font-weight: bold;">Attention:</span><br>
7715
7716
7717
7718
7719In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>),
7720the profile is constructed like described above, but starting from the
7721sea surface (k=nzt) down to the bottom boundary of the model. Height
7722levels 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>
7723
7724
7725
7726
7727 </td>
7728
7729
7730
7731
7732 </tr>
7733
7734
7735
7736
7737 <tr>
7738
7739
7740
7741
7742 <td style="vertical-align: top;"> 
7743     
7744     
7745     
7746     
7747      <p><a name="pt_vertical_gradient_level"></a><b>pt_vertical_gradient</b>
7748      <br>
7749
7750
7751
7752
7753 <b>_level</b></p>
7754
7755
7756
7757
7758 </td>
7759
7760
7761
7762
7763 <td style="vertical-align: top;">R (10)</td>
7764
7765
7766
7767
7768 <td style="vertical-align: top;"> 
7769     
7770     
7771     
7772     
7773      <p><i>10 *</i>&nbsp;
7774      <span style="font-style: italic;">0.0</span><br>
7775
7776
7777
7778
7779
7780      </p>
7781
7782
7783
7784
7785 </td>
7786
7787
7788
7789
7790 <td style="vertical-align: top;">
7791     
7792     
7793     
7794     
7795      <p>Height level from which on the temperature gradient defined by
7796      <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7797is effective (in m).&nbsp; </p>
7798
7799
7800
7801
7802 
7803     
7804     
7805     
7806     
7807      <p>The height levels have to be assigned in ascending order. The
7808default values result in a neutral stratification regardless of the
7809values of <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7810(unless the top boundary of the model is higher than 100000.0 m).
7811For the piecewise construction of temperature profiles see <a href="#pt_vertical_gradient">pt_vertical_gradient</a>.</p>
7812
7813
7814
7815
7816      <span style="font-weight: bold;">Attention:</span><br>
7817
7818
7819
7820
7821In 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.
7822      </td>
7823
7824
7825
7826
7827 </tr>
7828
7829
7830
7831
7832 <tr>
7833
7834
7835
7836
7837 <td style="vertical-align: top;"> 
7838     
7839     
7840     
7841     
7842      <p><a name="q_surface"></a><b>q_surface</b></p>
7843
7844
7845
7846
7847
7848      </td>
7849
7850
7851
7852
7853 <td style="vertical-align: top;">R</td>
7854
7855
7856
7857
7858
7859      <td style="vertical-align: top;"><i>0.0</i></td>
7860
7861
7862
7863
7864
7865      <td style="vertical-align: top;"> 
7866     
7867     
7868     
7869     
7870      <p>Surface
7871specific humidity / total water content (kg/kg).&nbsp; </p>
7872
7873
7874
7875
7876 
7877     
7878     
7879     
7880     
7881      <p>This
7882parameter assigns the value of the specific humidity q at
7883the surface (k=0).&nbsp; Starting from this value, the initial
7884humidity
7885profile is constructed with&nbsp; <a href="#q_vertical_gradient">q_vertical_gradient</a>
7886and <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
7887This profile is also used for the 1d-model as a stationary profile.</p>
7888
7889
7890
7891
7892
7893      </td>
7894
7895
7896
7897
7898 </tr>
7899
7900
7901
7902
7903 <tr>
7904
7905
7906
7907
7908 <td style="vertical-align: top;"> 
7909     
7910     
7911     
7912     
7913      <p><a name="q_surface_initial_change"></a><b>q_surface_initial</b>
7914      <br>
7915
7916
7917
7918
7919 <b>_change</b></p>
7920
7921
7922
7923
7924 </td>
7925
7926
7927
7928
7929 <td style="vertical-align: top;">R<br>
7930
7931
7932
7933
7934 </td>
7935
7936
7937
7938
7939 <td style="vertical-align: top;"><i>0.0</i></td>
7940
7941
7942
7943
7944
7945      <td style="vertical-align: top;"> 
7946     
7947     
7948     
7949     
7950      <p>Change in
7951surface specific humidity / total water content to
7952be made at the beginning
7953of the 3d run (kg/kg).&nbsp; </p>
7954
7955
7956
7957
7958 
7959     
7960     
7961     
7962     
7963      <p>If <b>q_surface_initial_change</b><i>
7964      </i>is set to a
7965non-zero value the
7966near surface latent heat flux (water flux) is not allowed to be given
7967simultaneously (see <a href="#surface_waterflux">surface_waterflux</a>).</p>
7968
7969
7970
7971
7972
7973      </td>
7974
7975
7976
7977
7978 </tr>
7979
7980
7981
7982
7983 <tr>
7984
7985
7986
7987
7988 <td style="vertical-align: top;"> 
7989     
7990     
7991     
7992     
7993      <p><a name="q_vertical_gradient"></a><b>q_vertical_gradient</b></p>
7994
7995
7996
7997
7998
7999      </td>
8000
8001
8002
8003
8004 <td style="vertical-align: top;">R (10)</td>
8005
8006
8007
8008
8009
8010      <td style="vertical-align: top;"><i>10 * 0.0</i></td>
8011
8012
8013
8014
8015
8016      <td style="vertical-align: top;"> 
8017     
8018     
8019     
8020     
8021      <p>Humidity
8022gradient(s) of the initial humidity profile
8023(in 1/100 m).&nbsp; </p>
8024
8025
8026
8027
8028 
8029     
8030     
8031     
8032     
8033      <p>This humidity gradient
8034holds starting from the height
8035level&nbsp; defined by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>
8036(precisely: for all uv levels k, where zu(k) &gt;
8037q_vertical_gradient_level,
8038q_init(k) is set: q_init(k) = q_init(k-1) + dzu(k) * <b>q_vertical_gradient</b>)
8039up to the top boundary or up to the next height level defined
8040by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
8041A total of 10 different gradients for 11 height intervals (10 intervals
8042if <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>(1)
8043= <i>0.0</i>) can be asigned. The surface humidity is
8044assigned
8045via <a href="#q_surface">q_surface</a>. </p>
8046
8047
8048
8049
8050
8051     
8052     
8053     
8054     
8055      <p>Example:&nbsp; </p>
8056
8057
8058
8059
8060 
8061     
8062     
8063     
8064     
8065      <ul>
8066
8067
8068
8069
8070 
8071       
8072       
8073       
8074       
8075        <p><b>q_vertical_gradient</b>
8076= <i>0.001</i>, <i>0.0005</i>,&nbsp; <br>
8077
8078
8079
8080
8081
8082        <b>q_vertical_gradient_level</b> = <i>500.0</i>,
8083        <i>1000.0</i>,</p>
8084
8085
8086
8087
8088 
8089     
8090     
8091     
8092     
8093      </ul>
8094
8095
8096
8097
8098
8099That defines the humidity to be constant with height up to z =
8100500.0
8101m with a
8102value given by <a href="#q_surface">q_surface</a>.
8103For 500.0 m &lt; z &lt;= 1000.0 m the humidity gradient is
81040.001 / 100
8105m and for z &gt; 1000.0 m up to the top boundary it is
81060.0005 / 100 m (it is assumed that the assigned height levels
8107correspond with uv
8108levels). </td>
8109
8110
8111
8112
8113 </tr>
8114
8115
8116
8117
8118 <tr>
8119
8120
8121
8122
8123 <td style="vertical-align: top;"> 
8124     
8125     
8126     
8127     
8128      <p><a name="q_vertical_gradient_level"></a><b>q_vertical_gradient</b>
8129      <br>
8130
8131
8132
8133
8134 <b>_level</b></p>
8135
8136
8137
8138
8139 </td>
8140
8141
8142
8143
8144 <td style="vertical-align: top;">R (10)</td>
8145
8146
8147
8148
8149 <td style="vertical-align: top;"> 
8150     
8151     
8152     
8153     
8154      <p><i>10 *</i>&nbsp;
8155      <i>0.0</i></p>
8156
8157
8158
8159
8160 </td>
8161
8162
8163
8164
8165 <td style="vertical-align: top;"> 
8166     
8167     
8168     
8169     
8170      <p>Height level from
8171which on the humidity gradient defined by <a href="#q_vertical_gradient">q_vertical_gradient</a>
8172is effective (in m).&nbsp; </p>
8173
8174
8175
8176
8177 
8178     
8179     
8180     
8181     
8182      <p>The height levels
8183are to be assigned in ascending order. The
8184default values result in a humidity constant with height regardless of
8185the values of <a href="#q_vertical_gradient">q_vertical_gradient</a>
8186(unless the top boundary of the model is higher than 100000.0 m). For
8187the piecewise construction of humidity profiles see <a href="#q_vertical_gradient">q_vertical_gradient</a>.</p>
8188
8189
8190
8191
8192
8193      </td>
8194
8195
8196
8197
8198 </tr>
8199
8200
8201
8202
8203 <tr>
8204
8205
8206
8207
8208 <td style="vertical-align: top;"> 
8209     
8210     
8211     
8212     
8213      <p><a name="radiation"></a><b>radiation</b></p>
8214
8215
8216
8217
8218
8219      </td>
8220
8221
8222
8223
8224 <td style="vertical-align: top;">L</td>
8225
8226
8227
8228
8229
8230      <td style="vertical-align: top;"><i>.F.</i></td>
8231
8232
8233
8234
8235
8236      <td style="vertical-align: top;"> 
8237     
8238     
8239     
8240     
8241      <p>Parameter to
8242switch on longwave radiation cooling at
8243cloud-tops.&nbsp; </p>
8244
8245
8246
8247
8248 
8249     
8250     
8251     
8252     
8253      <p>Long-wave radiation
8254processes are parameterized by the
8255effective emissivity, which considers only the absorption and emission
8256of long-wave radiation at cloud droplets. The radiation scheme can be
8257used only with <a href="#cloud_physics">cloud_physics</a>
8258= .TRUE. .</p>
8259
8260
8261
8262
8263 </td>
8264
8265
8266
8267
8268 </tr>
8269
8270
8271
8272
8273 <tr>
8274
8275
8276
8277
8278 <td style="vertical-align: top;"> 
8279     
8280     
8281     
8282     
8283      <p><a name="random_generator"></a><b>random_generator</b></p>
8284
8285
8286
8287
8288
8289      </td>
8290
8291
8292
8293
8294 <td style="vertical-align: top;">C * 20</td>
8295
8296
8297
8298
8299
8300      <td style="vertical-align: top;"> 
8301     
8302     
8303     
8304     
8305      <p><i>'numerical</i><br>
8306
8307
8308
8309
8310
8311      <i>recipes'</i></p>
8312
8313
8314
8315
8316 </td>
8317
8318
8319
8320
8321 <td style="vertical-align: top;"> 
8322     
8323     
8324     
8325     
8326      <p>Random number
8327generator to be used for creating uniformly
8328distributed random numbers. <br>
8329
8330
8331
8332
8333 </p>
8334
8335
8336
8337
8338 
8339     
8340     
8341     
8342     
8343      <p>It is
8344used if random perturbations are to be imposed on the
8345velocity field or on the surface heat flux field (see <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>
8346and <a href="chapter_4.2.html#random_heatflux">random_heatflux</a>).
8347By default, the "Numerical Recipes" random number generator is used.
8348This one provides exactly the same order of random numbers on all
8349different machines and should be used in particular for comparison runs.<br>
8350
8351
8352
8353
8354
8355      <br>
8356
8357
8358
8359
8360
8361Besides, a system-specific generator is available ( <b>random_generator</b>
8362= <i>'system-specific')</i> which should particularly be
8363used for runs
8364on vector parallel computers (NEC), because the default generator
8365cannot be vectorized and therefore significantly drops down the code
8366performance on these machines.<br>
8367
8368
8369
8370
8371 </p>
8372
8373
8374
8375
8376 <span style="font-weight: bold;">Note:</span><br>
8377
8378
8379
8380
8381
8382Results from two otherwise identical model runs will not be comparable
8383one-to-one if they used different random number generators.</td>
8384
8385
8386
8387
8388 </tr>
8389
8390
8391
8392
8393
8394    <tr>
8395
8396
8397
8398
8399 <td style="vertical-align: top;"> 
8400     
8401     
8402     
8403     
8404      <p><a name="random_heatflux"></a><b>random_heatflux</b></p>
8405
8406
8407
8408
8409
8410      </td>
8411
8412
8413
8414
8415 <td style="vertical-align: top;">L</td>
8416
8417
8418
8419
8420
8421      <td style="vertical-align: top;"><i>.F.</i></td>
8422
8423
8424
8425
8426
8427      <td style="vertical-align: top;"> 
8428     
8429     
8430     
8431     
8432      <p>Parameter to
8433impose random perturbations on the internal two-dimensional near
8434surface heat flux field <span style="font-style: italic;">shf</span>.
8435      <br>
8436
8437
8438
8439
8440 </p>
8441
8442
8443
8444
8445If a near surface heat flux is used as bottom
8446boundary
8447condition (see <a href="#surface_heatflux">surface_heatflux</a>),
8448it is by default assumed to be horizontally homogeneous. Random
8449perturbations can be imposed on the internal
8450two-dimensional&nbsp;heat flux field <span style="font-style: italic;">shf</span> by assigning <b>random_heatflux</b>
8451= <i>.T.</i>. The disturbed heat flux field is calculated
8452by
8453multiplying the
8454values at each mesh point with a normally distributed random number
8455with a mean value and standard deviation of 1. This is repeated after
8456every timestep.<br>
8457
8458
8459
8460
8461 <br>
8462
8463
8464
8465
8466
8467In case of a non-flat <a href="#topography">topography</a>,&nbsp;assigning
8468      <b>random_heatflux</b>
8469= <i>.T.</i> imposes random perturbations on the
8470combined&nbsp;heat
8471flux field <span style="font-style: italic;">shf</span>
8472composed of <a href="#surface_heatflux">surface_heatflux</a>
8473at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
8474at the topography top face.</td>
8475
8476
8477
8478
8479 </tr>
8480
8481
8482
8483
8484 <tr>
8485
8486
8487
8488
8489 <td style="vertical-align: top;"> 
8490     
8491     
8492     
8493     
8494      <p><a name="rif_max"></a><b>rif_max</b></p>
8495
8496
8497
8498
8499
8500      </td>
8501
8502
8503
8504
8505 <td style="vertical-align: top;">R</td>
8506
8507
8508
8509
8510
8511      <td style="vertical-align: top;"><i>1.0</i></td>
8512
8513
8514
8515
8516
8517      <td style="vertical-align: top;"> 
8518     
8519     
8520     
8521     
8522      <p>Upper limit of
8523the flux-Richardson number.&nbsp; </p>
8524
8525
8526
8527
8528 
8529     
8530     
8531     
8532     
8533      <p>With the
8534Prandtl layer switched on (see <a href="#prandtl_layer">prandtl_layer</a>),
8535flux-Richardson numbers (rif) are calculated for z=z<sub>p</sub>
8536(k=1)
8537in the 3d-model (in the 1d model for all heights). Their values in
8538particular determine the
8539values of the friction velocity (1d- and 3d-model) and the values of
8540the eddy diffusivity (1d-model). With small wind velocities at the
8541Prandtl layer top or small vertical wind shears in the 1d-model, rif
8542can take up unrealistic large values. They are limited by an upper (<span style="font-weight: bold;">rif_max</span>) and lower
8543limit (see <a href="#rif_min">rif_min</a>)
8544for the flux-Richardson number. The condition <b>rif_max</b>
8545&gt; <b>rif_min</b>
8546must be met.</p>
8547
8548
8549
8550
8551 </td>
8552
8553
8554
8555
8556 </tr>
8557
8558
8559
8560
8561 <tr>
8562
8563
8564
8565
8566 <td style="vertical-align: top;"> 
8567     
8568     
8569     
8570     
8571      <p><a name="rif_min"></a><b>rif_min</b></p>
8572
8573
8574
8575
8576
8577      </td>
8578
8579
8580
8581
8582 <td style="vertical-align: top;">R</td>
8583
8584
8585
8586
8587
8588      <td style="vertical-align: top;"><i>- 5.0</i></td>
8589
8590
8591
8592
8593
8594      <td style="vertical-align: top;"> 
8595     
8596     
8597     
8598     
8599      <p>Lower limit of
8600the flux-Richardson number.&nbsp; </p>
8601
8602
8603
8604
8605 
8606     
8607     
8608     
8609     
8610      <p>For further
8611explanations see <a href="#rif_max">rif_max</a>.
8612The condition <b>rif_max</b> &gt; <b>rif_min </b>must
8613be met.</p>
8614
8615
8616
8617
8618 </td>
8619
8620
8621
8622
8623 </tr>
8624
8625
8626
8627
8628 <tr>
8629
8630
8631
8632
8633 <td style="vertical-align: top;"> 
8634     
8635     
8636     
8637     
8638      <p><a name="roughness_length"></a><b>roughness_length</b></p>
8639
8640
8641
8642
8643
8644      </td>
8645
8646
8647
8648
8649 <td style="vertical-align: top;">R</td>
8650
8651
8652
8653
8654
8655      <td style="vertical-align: top;"><i>0.1</i></td>
8656
8657
8658
8659
8660
8661      <td style="vertical-align: top;"> 
8662     
8663     
8664     
8665     
8666      <p>Roughness
8667length (in m).&nbsp; </p>
8668
8669
8670
8671
8672 
8673     
8674     
8675     
8676     
8677      <p>This parameter is
8678effective only in case that a Prandtl layer
8679is switched
8680on (see <a href="#prandtl_layer">prandtl_layer</a>).</p>
8681
8682
8683
8684
8685
8686      </td>
8687
8688
8689
8690
8691 </tr>
8692
8693
8694
8695
8696 <tr>
8697
8698
8699
8700
8701      <td style="vertical-align: top;"><a name="sa_surface"></a><span style="font-weight: bold;">sa_surface</span></td>
8702
8703
8704
8705
8706      <td style="vertical-align: top;">R</td>
8707
8708
8709
8710
8711      <td style="vertical-align: top;"><span style="font-style: italic;">35.0</span></td>
8712
8713
8714
8715
8716      <td style="vertical-align: top;"> 
8717     
8718     
8719     
8720     
8721      <p>Surface salinity (in psu).&nbsp;</p>
8722
8723
8724
8725
8726This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).
8727     
8728     
8729     
8730     
8731      <p>This
8732parameter 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,
8733the
8734initial 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>
8735and&nbsp;<a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level
8736      </a>.</p>
8737
8738
8739
8740
8741      </td>
8742
8743
8744
8745
8746    </tr>
8747
8748
8749
8750
8751    <tr>
8752
8753
8754
8755
8756      <td style="vertical-align: top;"><a name="sa_vertical_gradient"></a><span style="font-weight: bold;">sa_vertical_gradient</span></td>
8757
8758
8759
8760
8761      <td style="vertical-align: top;">R(10)</td>
8762
8763
8764
8765
8766      <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
8767
8768
8769
8770
8771      <td style="vertical-align: top;">
8772     
8773     
8774     
8775     
8776      <p>Salinity gradient(s) of the initial salinity profile (in psu
8777/ 100 m).&nbsp; </p>
8778
8779
8780
8781
8782 
8783     
8784     
8785     
8786     
8787      <p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
8788
8789
8790
8791
8792     
8793     
8794     
8795     
8796      <p>This salinity gradient
8797holds starting from the height&nbsp;
8798level defined by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>
8799(precisely: for all uv levels k where zu(k) &lt;
8800sa_vertical_gradient_level, sa_init(k) is set: sa_init(k) =
8801sa_init(k+1) - dzu(k+1) * <b>sa_vertical_gradient</b>) down to the bottom boundary or down to the next height level defined
8802by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>.
8803A total of 10 different gradients for 11 height intervals (10 intervals
8804if <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>(1)
8805= <i>0.0</i>) can be assigned. The surface salinity at k=nzt is
8806assigned via <a href="chapter_4.1.html#sa_surface">sa_surface</a>.&nbsp;
8807      </p>
8808
8809
8810
8811
8812 
8813     
8814     
8815     
8816     
8817      <p>Example:&nbsp; </p>
8818
8819
8820
8821
8822 
8823     
8824     
8825     
8826     
8827      <ul>
8828
8829
8830
8831
8832       
8833       
8834       
8835       
8836        <p><b>sa_vertical_gradient</b>
8837= <i>1.0</i>, <i>0.5</i>,&nbsp; <br>
8838
8839
8840
8841
8842
8843        <b>sa_vertical_gradient_level</b> = <i>-500.0</i>,
8844-<i>1000.0</i>,</p>
8845
8846
8847
8848
8849     
8850     
8851     
8852     
8853      </ul>
8854
8855
8856
8857
8858 
8859     
8860     
8861     
8862     
8863      <p>That
8864defines 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>.
8865For -500.0 m &lt; z &lt;= -1000.0 m the salinity gradient is
88661.0 psu /
8867100 m and for z &lt; -1000.0 m down to the bottom boundary it is
88680.5 psu / 100 m (it is assumed that the assigned height levels correspond
8869with uv levels).</p>
8870
8871
8872
8873
8874      </td>
8875
8876
8877
8878
8879    </tr>
8880
8881
8882
8883
8884    <tr>
8885
8886
8887
8888
8889      <td style="vertical-align: top;"><a name="sa_vertical_gradient_level"></a><span style="font-weight: bold;">sa_vertical_gradient_level</span></td>
8890
8891
8892
8893
8894      <td style="vertical-align: top;">R(10)</td>
8895
8896
8897
8898
8899      <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
8900
8901
8902
8903
8904      <td style="vertical-align: top;">
8905     
8906     
8907     
8908     
8909      <p>Height level from which on the salinity gradient defined by <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
8910is effective (in m).&nbsp; </p>
8911
8912
8913
8914
8915 
8916     
8917     
8918     
8919     
8920      <p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
8921
8922
8923
8924
8925     
8926     
8927     
8928     
8929      <p>The height levels have to be assigned in descending order. The
8930default values result in a constant salinity profile regardless of the
8931values of <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
8932(unless the bottom boundary of the model is lower than -100000.0 m).
8933For the piecewise construction of salinity profiles see <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>.</p>
8934
8935
8936
8937
8938      </td>
8939
8940
8941
8942
8943    </tr>
8944
8945
8946
8947
8948    <tr>
8949
8950
8951
8952
8953 <td style="vertical-align: top;"> 
8954     
8955     
8956     
8957     
8958      <p><a name="scalar_advec"></a><b>scalar_advec</b></p>
8959
8960
8961
8962
8963
8964      </td>
8965
8966
8967
8968
8969 <td style="vertical-align: top;">C * 10</td>
8970
8971
8972
8973
8974
8975      <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
8976
8977
8978
8979
8980
8981      <td style="vertical-align: top;"> 
8982     
8983     
8984     
8985     
8986      <p>Advection
8987scheme to be used for the scalar quantities.&nbsp; </p>
8988
8989
8990
8991
8992 
8993     
8994     
8995     
8996     
8997      <p>The
8998user can choose between the following schemes:<br>
8999
9000
9001
9002
9003 </p>
9004
9005
9006
9007
9008 
9009     
9010     
9011     
9012     
9013      <p><span style="font-style: italic;">'pw-scheme'</span><br>
9014
9015
9016
9017
9018
9019      </p>
9020
9021
9022
9023
9024 
9025     
9026     
9027     
9028     
9029      <div style="margin-left: 40px;">The scheme of
9030Piascek and
9031Williams (1970, J. Comp. Phys., 6,
9032392-405) with central differences in the form C3 is used.<br>
9033
9034
9035
9036
9037
9038If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
9039= <span style="font-style: italic;">'leapfrog+euler'</span>
9040the
9041advection scheme is - for the Euler-timestep - automatically switched
9042to an upstream-scheme. <br>
9043
9044
9045
9046
9047 </div>
9048
9049
9050
9051
9052 <br>
9053
9054
9055
9056
9057 
9058     
9059     
9060     
9061     
9062      <p><span style="font-style: italic;">'bc-scheme'</span><br>
9063
9064
9065
9066
9067
9068      </p>
9069
9070
9071
9072
9073 
9074     
9075     
9076     
9077     
9078      <div style="margin-left: 40px;">The Bott
9079scheme modified by
9080Chlond (1994, Mon.
9081Wea. Rev., 122, 111-125). This is a conservative monotonous scheme with
9082very small numerical diffusion and therefore very good conservation of
9083scalar flow features. The scheme however, is computationally very
9084expensive both because it is expensive itself and because it does (so
9085far) not allow specific code optimizations (e.g. cache optimization).
9086Choice of this
9087scheme forces the Euler timestep scheme to be used for the scalar
9088quantities. For output of horizontally averaged
9089profiles of the resolved / total heat flux, <a href="chapter_4.2.html#data_output_pr">data_output_pr</a>
9090= <i>'w*pt*BC'</i> / <i>'wptBC' </i>should
9091be used, instead of the
9092standard profiles (<span style="font-style: italic;">'w*pt*'</span>
9093and <span style="font-style: italic;">'wpt'</span>)
9094because these are
9095too inaccurate with this scheme. However, for subdomain analysis (see <a href="#statistic_regions">statistic_regions</a>)
9096exactly the reverse holds: here <i>'w*pt*BC'</i> and <i>'wptBC'</i>
9097show very large errors and should not be used.<br>
9098
9099
9100
9101
9102 <br>
9103
9104
9105
9106
9107
9108This scheme is not allowed for non-cyclic lateral boundary conditions
9109(see <a href="#bc_lr">bc_lr</a>
9110and <a href="#bc_ns">bc_ns</a>).<br>
9111
9112
9113
9114
9115 <br>
9116
9117
9118
9119
9120
9121      </div>
9122
9123
9124
9125
9126 <span style="font-style: italic;">'ups-scheme'</span><br>
9127
9128
9129
9130
9131
9132     
9133     
9134     
9135     
9136      <p style="margin-left: 40px;">The upstream-spline-scheme
9137is used
9138(see Mahrer and Pielke,
91391978: Mon. Wea. Rev., 106, 818-830). In opposite to the Piascek
9140Williams scheme, this is characterized by much better numerical
9141features (less numerical diffusion, better preservation of flux
9142structures, e.g. vortices), but computationally it is much more
9143expensive. In
9144addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
9145= <span style="font-style: italic;">'</span><i>euler'</i>),
9146i.e. the
9147timestep accuracy is only first order. For this reason the advection of
9148momentum (see <a href="#momentum_advec">momentum_advec</a>)
9149should then also be carried out with the upstream-spline scheme,
9150because otherwise the momentum would
9151be subject to large numerical diffusion due to the upstream
9152scheme.&nbsp; </p>
9153
9154
9155
9156
9157 
9158     
9159     
9160     
9161     
9162      <p style="margin-left: 40px;">Since
9163the cubic splines used tend
9164to overshoot under
9165certain circumstances, this effect must be adjusted by suitable
9166filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
9167      <a href="#long_filter_factor">long_filter_factor</a>,
9168      <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>).
9169This is always neccesssary for runs with stable stratification,
9170even if this stratification appears only in parts of the model
9171domain.&nbsp; </p>
9172
9173
9174
9175
9176 
9177     
9178     
9179     
9180     
9181      <p style="margin-left: 40px;">With
9182stable stratification the
9183upstream-upline scheme also produces gravity waves with large
9184amplitude, which must be
9185suitably damped (see <a href="chapter_4.2.html#rayleigh_damping_factor">rayleigh_damping_factor</a>).<br>
9186
9187
9188
9189
9190
9191      </p>
9192
9193
9194
9195
9196 
9197     
9198     
9199     
9200     
9201      <p style="margin-left: 40px;"><span style="font-weight: bold;">Important: </span>The&nbsp;
9202upstream-spline scheme is not implemented for humidity and passive
9203scalars (see&nbsp;<a href="#humidity">humidity</a>
9204and <a href="#passive_scalar">passive_scalar</a>)
9205and requires the use of a 2d-domain-decomposition. The last conditions
9206severely restricts code optimization on several machines leading to
9207very long execution times! This scheme is also not allowed for
9208non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
9209and <a href="#bc_ns">bc_ns</a>).</p>
9210
9211
9212
9213
9214      <br>
9215
9216
9217
9218
9219A
9220differing advection scheme can be choosed for the subgrid-scale TKE
9221using parameter <a href="chapter_4.1.html#use_upstream_for_tke">use_upstream_for_tke</a>.</td>
9222
9223
9224
9225
9226
9227    </tr>
9228
9229
9230
9231
9232 <tr>
9233
9234
9235
9236
9237 <td style="vertical-align: top;">
9238     
9239     
9240     
9241     
9242      <p><a name="statistic_regions"></a><b>statistic_regions</b></p>
9243
9244
9245
9246
9247
9248      </td>
9249
9250
9251
9252
9253 <td style="vertical-align: top;">I</td>
9254
9255
9256
9257
9258
9259      <td style="vertical-align: top;"><i>0</i></td>
9260
9261
9262
9263
9264
9265      <td style="vertical-align: top;"> 
9266     
9267     
9268     
9269     
9270      <p>Number of
9271additional user-defined subdomains for which
9272statistical analysis
9273and corresponding output (profiles, time series) shall be
9274made.&nbsp; </p>
9275
9276
9277
9278
9279 
9280     
9281     
9282     
9283     
9284      <p>By default, vertical profiles and
9285other statistical quantities
9286are calculated as horizontal and/or volume average of the total model
9287domain. Beyond that, these calculations can also be carried out for
9288subdomains which can be defined using the field <a href="chapter_3.5.3.html">rmask </a>within the
9289user-defined software
9290(see <a href="chapter_3.5.3.html">chapter
92913.5.3</a>). The number of these subdomains is determined with the
9292parameter <b>statistic_regions</b>. Maximum 9 additional
9293subdomains
9294are allowed. The parameter <a href="chapter_4.3.html#region">region</a>
9295can be used to assigned names (identifier) to these subdomains which
9296are then used in the headers
9297of the output files and plots.</p>
9298
9299
9300
9301
9302     
9303     
9304     
9305     
9306      <p>If the default NetCDF
9307output format is selected (see parameter <a href="chapter_4.2.html#data_output_format">data_output_format</a>),
9308data for the total domain and all defined subdomains are output to the
9309same file(s) (<a href="chapter_3.4.html#DATA_1D_PR_NETCDF">DATA_1D_PR_NETCDF</a>,
9310      <a href="chapter_3.4.html#DATA_1D_TS_NETCDF">DATA_1D_TS_NETCDF</a>).
9311In case of <span style="font-weight: bold;">statistic_regions</span>
9312&gt; <span style="font-style: italic;">0</span>,
9313data on the file for the different domains can be distinguished by a
9314suffix which is appended to the quantity names. Suffix 0 means data for
9315the total domain, suffix 1 means data for subdomain 1, etc.</p>
9316
9317
9318
9319
9320     
9321     
9322     
9323     
9324      <p>In
9325case of <span style="font-weight: bold;">data_output_format</span>
9326= <span style="font-style: italic;">'profil'</span>,
9327individual local files for profiles (<a href="chapter_3.4.html#PLOT1D_DATA">PLOT1D_DATA</a>)&nbsp;are
9328created for each subdomain. The individual subdomain files differ by
9329their name (the
9330number of the respective subdomain is attached, e.g.
9331PLOT1D_DATA_1). In this case the name of the file with the data of
9332the total domain is PLOT1D_DATA_0. If no subdomains
9333are declared (<b>statistic_regions</b> = <i>0</i>),
9334the name
9335PLOT1D_DATA is used (this must be considered in the
9336respective file connection statements of the <span style="font-weight: bold;">mrun</span> configuration
9337file).</p>
9338
9339
9340
9341
9342 </td>
9343
9344
9345
9346
9347 </tr>
9348
9349
9350
9351
9352 <tr>
9353
9354
9355
9356
9357 <td style="vertical-align: top;"> 
9358     
9359     
9360     
9361     
9362      <p><a name="surface_heatflux"></a><b>surface_heatflux</b></p>
9363
9364
9365
9366
9367
9368      </td>
9369
9370
9371
9372
9373 <td style="vertical-align: top;">R</td>
9374
9375
9376
9377
9378
9379      <td style="vertical-align: top;"><span style="font-style: italic;">no prescribed<br>
9380
9381
9382
9383
9384
9385heatflux<br>
9386
9387
9388
9389
9390 </span></td>
9391
9392
9393
9394
9395 <td style="vertical-align: top;"> 
9396     
9397     
9398     
9399     
9400      <p>Kinematic sensible
9401heat flux at the bottom surface (in K m/s).&nbsp; </p>
9402
9403
9404
9405
9406 
9407     
9408     
9409     
9410     
9411      <p>If
9412a value is assigned to this parameter, the internal two-dimensional
9413surface heat flux field <span style="font-style: italic;">shf</span>
9414is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>&nbsp;as
9415bottom (horizontally homogeneous) boundary condition for the
9416temperature equation. This additionally requires that a Neumann
9417condition must be used for the potential temperature (see <a href="#bc_pt_b">bc_pt_b</a>),
9418because otherwise the resolved scale may contribute to
9419the surface flux so that a constant value cannot be guaranteed. Also,
9420changes of the
9421surface temperature (see <a href="#pt_surface_initial_change">pt_surface_initial_change</a>)
9422are not allowed. The parameter <a href="#random_heatflux">random_heatflux</a>
9423can be used to impose random perturbations on the (homogeneous) surface
9424heat
9425flux field <span style="font-style: italic;">shf</span>.&nbsp;</p>
9426
9427
9428
9429
9430
9431     
9432     
9433     
9434     
9435      <p>
9436In case of a non-flat <a href="#topography">topography</a>,&nbsp;the
9437internal two-dimensional&nbsp;surface heat
9438flux field <span style="font-style: italic;">shf</span>
9439is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>
9440at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
9441at the topography top face.&nbsp;The parameter<a href="#random_heatflux"> random_heatflux</a>
9442can be used to impose random perturbations on this combined surface
9443heat
9444flux field <span style="font-style: italic;">shf</span>.&nbsp;
9445      </p>
9446
9447
9448
9449
9450 
9451     
9452     
9453     
9454     
9455      <p>If no surface heat flux is assigned, <span style="font-style: italic;">shf</span> is calculated
9456at each timestep by u<sub>*</sub> * theta<sub>*</sub>
9457(of course only with <a href="#prandtl_layer">prandtl_layer</a>
9458switched on). Here, u<sub>*</sub>
9459and theta<sub>*</sub> are calculated from the Prandtl law
9460assuming
9461logarithmic wind and temperature
9462profiles between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_pt_b">bc_pt_b</a>)
9463must be used as bottom boundary condition for the potential temperature.</p>
9464
9465
9466
9467
9468     
9469     
9470     
9471     
9472      <p>See
9473also <a href="#top_heatflux">top_heatflux</a>.</p>
9474
9475
9476
9477
9478
9479      </td>
9480
9481
9482
9483
9484 </tr>
9485
9486
9487
9488
9489 <tr>
9490
9491
9492
9493
9494 <td style="vertical-align: top;"> 
9495     
9496     
9497     
9498     
9499      <p><a name="surface_pressure"></a><b>surface_pressure</b></p>
9500
9501
9502
9503
9504
9505      </td>
9506
9507
9508
9509
9510 <td style="vertical-align: top;">R</td>
9511
9512
9513
9514
9515
9516      <td style="vertical-align: top;"><i>1013.25</i></td>
9517
9518
9519
9520
9521
9522      <td style="vertical-align: top;"> 
9523     
9524     
9525     
9526     
9527      <p>Atmospheric
9528pressure at the surface (in hPa).&nbsp; </p>
9529
9530
9531
9532
9533
9534Starting from this surface value, the vertical pressure
9535profile is calculated once at the beginning of the run assuming a
9536neutrally stratified
9537atmosphere. This is needed for
9538converting between the liquid water potential temperature and the
9539potential temperature (see <a href="#cloud_physics">cloud_physics</a><span style="text-decoration: underline;"></span>).</td>
9540
9541
9542
9543
9544
9545    </tr>
9546
9547
9548
9549
9550 <tr>
9551
9552
9553
9554
9555 <td style="vertical-align: top;">
9556     
9557     
9558     
9559     
9560      <p><a name="surface_scalarflux"></a><b>surface_scalarflux</b></p>
9561
9562
9563
9564
9565
9566      </td>
9567
9568
9569
9570
9571 <td style="vertical-align: top;">R</td>
9572
9573
9574
9575
9576
9577      <td style="vertical-align: top;"><i>0.0</i></td>
9578
9579
9580
9581
9582
9583      <td style="vertical-align: top;"> 
9584     
9585     
9586     
9587     
9588      <p>Scalar flux at
9589the surface (in kg/(m<sup>2</sup> s)).&nbsp; </p>
9590
9591
9592
9593
9594
9595     
9596     
9597     
9598     
9599      <p>If a non-zero value is assigned to this parameter, the
9600respective scalar flux value is used
9601as bottom (horizontally homogeneous) boundary condition for the scalar
9602concentration equation.&nbsp;This additionally requires that a
9603Neumann
9604condition must be used for the scalar concentration&nbsp;(see <a href="#bc_s_b">bc_s_b</a>),
9605because otherwise the resolved scale may contribute to
9606the surface flux so that a constant value cannot be guaranteed. Also,
9607changes of the
9608surface scalar concentration (see <a href="#s_surface_initial_change">s_surface_initial_change</a>)
9609are not allowed. <br>
9610
9611
9612
9613
9614 </p>
9615
9616
9617
9618
9619 
9620     
9621     
9622     
9623     
9624      <p>If no surface scalar
9625flux is assigned (<b>surface_scalarflux</b>
9626= <i>0.0</i>),
9627it is calculated at each timestep by u<sub>*</sub> * s<sub>*</sub>
9628(of course only with Prandtl layer switched on). Here, s<sub>*</sub>
9629is calculated from the Prandtl law assuming a logarithmic scalar
9630concentration
9631profile between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_s_b">bc_s_b</a>)
9632must be used as bottom boundary condition for the scalar concentration.</p>
9633
9634
9635
9636
9637
9638      </td>
9639
9640
9641
9642
9643 </tr>
9644
9645
9646
9647
9648 <tr>
9649
9650
9651
9652
9653 <td style="vertical-align: top;"> 
9654     
9655     
9656     
9657     
9658      <p><a name="surface_waterflux"></a><b>surface_waterflux</b></p>
9659
9660
9661
9662
9663
9664      </td>
9665
9666
9667
9668
9669 <td style="vertical-align: top;">R</td>
9670
9671
9672
9673
9674
9675      <td style="vertical-align: top;"><i>0.0</i></td>
9676
9677
9678
9679
9680
9681      <td style="vertical-align: top;"> 
9682     
9683     
9684     
9685     
9686      <p>Kinematic
9687water flux near the surface (in m/s).&nbsp; </p>
9688
9689
9690
9691
9692 
9693     
9694     
9695     
9696     
9697      <p>If
9698a non-zero value is assigned to this parameter, the
9699respective water flux value is used
9700as bottom (horizontally homogeneous) boundary condition for the
9701humidity equation. This additionally requires that a Neumann
9702condition must be used for the specific humidity / total water content
9703(see <a href="#bc_q_b">bc_q_b</a>),
9704because otherwise the resolved scale may contribute to
9705the surface flux so that a constant value cannot be guaranteed. Also,
9706changes of the
9707surface humidity (see <a href="#q_surface_initial_change">q_surface_initial_change</a>)
9708are not allowed.<br>
9709
9710
9711
9712
9713 </p>
9714
9715
9716
9717
9718 
9719     
9720     
9721     
9722     
9723      <p>If no surface water
9724flux is assigned (<b>surface_waterflux</b>
9725= <i>0.0</i>),
9726it is calculated at each timestep by u<sub>*</sub> * q<sub>*</sub>
9727(of course only with Prandtl layer switched on). Here, q<sub>*</sub>
9728is calculated from the Prandtl law assuming a logarithmic temperature
9729profile between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_q_b">bc_q_b</a>)
9730must be used as the bottom boundary condition for the humidity.</p>
9731
9732
9733
9734
9735
9736      </td>
9737
9738
9739
9740
9741 </tr>
9742
9743
9744
9745
9746 <tr>
9747
9748
9749
9750
9751 <td style="vertical-align: top;"> 
9752     
9753     
9754     
9755     
9756      <p><a name="s_surface"></a><b>s_surface</b></p>
9757
9758
9759
9760
9761
9762      </td>
9763
9764
9765
9766
9767 <td style="vertical-align: top;">R</td>
9768
9769
9770
9771
9772
9773      <td style="vertical-align: top;"><i>0.0</i></td>
9774
9775
9776
9777
9778
9779      <td style="vertical-align: top;"> 
9780     
9781     
9782     
9783     
9784      <p>Surface value
9785of the passive scalar (in kg/m<sup>3</sup>).&nbsp;<br>
9786
9787
9788
9789
9790
9791      </p>
9792
9793
9794
9795
9796
9797This parameter assigns the value of the passive scalar s at
9798the surface (k=0)<b>.</b> Starting from this value, the
9799initial vertical scalar concentration profile is constructed with<a href="#s_vertical_gradient">
9800s_vertical_gradient</a> and <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.</td>
9801
9802
9803
9804
9805
9806    </tr>
9807
9808
9809
9810
9811 <tr>
9812
9813
9814
9815
9816 <td style="vertical-align: top;">
9817     
9818     
9819     
9820     
9821      <p><a name="s_surface_initial_change"></a><b>s_surface_initial</b>
9822      <br>
9823
9824
9825
9826
9827 <b>_change</b></p>
9828
9829
9830
9831
9832 </td>
9833
9834
9835
9836
9837 <td style="vertical-align: top;">R</td>
9838
9839
9840
9841
9842 <td style="vertical-align: top;"><i>0.0</i></td>
9843
9844
9845
9846
9847
9848      <td style="vertical-align: top;"> 
9849     
9850     
9851     
9852     
9853      <p>Change in
9854surface scalar concentration to be made at the
9855beginning of the 3d run (in kg/m<sup>3</sup>).&nbsp; </p>
9856
9857
9858
9859
9860
9861     
9862     
9863     
9864     
9865      <p>If <b>s_surface_initial_change</b><i>&nbsp;</i>is
9866set to a
9867non-zero
9868value, the near surface scalar flux is not allowed to be given
9869simultaneously (see <a href="#surface_scalarflux">surface_scalarflux</a>).</p>
9870
9871
9872
9873
9874
9875      </td>
9876
9877
9878
9879
9880 </tr>
9881
9882
9883
9884
9885 <tr>
9886
9887
9888
9889
9890 <td style="vertical-align: top;"> 
9891     
9892     
9893     
9894     
9895      <p><a name="s_vertical_gradient"></a><b>s_vertical_gradient</b></p>
9896
9897
9898
9899
9900
9901      </td>
9902
9903
9904
9905
9906 <td style="vertical-align: top;">R (10)</td>
9907
9908
9909
9910
9911
9912      <td style="vertical-align: top;"><i>10 * 0</i><i>.0</i></td>
9913
9914
9915
9916
9917
9918      <td style="vertical-align: top;"> 
9919     
9920     
9921     
9922     
9923      <p>Scalar
9924concentration gradient(s) of the initial scalar
9925concentration profile (in kg/m<sup>3 </sup>/
9926100 m).&nbsp; </p>
9927
9928
9929
9930
9931 
9932     
9933     
9934     
9935     
9936      <p>The scalar gradient holds
9937starting from the height level
9938defined by <a href="#s_vertical_gradient_level">s_vertical_gradient_level
9939      </a>(precisely: for all uv levels k, where zu(k) &gt;
9940s_vertical_gradient_level, s_init(k) is set: s_init(k) = s_init(k-1) +
9941dzu(k) * <b>s_vertical_gradient</b>) up to the top
9942boundary or up to
9943the next height level defined by <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
9944A total of 10 different gradients for 11 height intervals (10 intervals
9945if <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>(1)
9946= <i>0.0</i>) can be assigned. The surface scalar value is
9947assigned
9948via <a href="#s_surface">s_surface</a>.<br>
9949
9950
9951
9952
9953 </p>
9954
9955
9956
9957
9958
9959     
9960     
9961     
9962     
9963      <p>Example:&nbsp; </p>
9964
9965
9966
9967
9968 
9969     
9970     
9971     
9972     
9973      <ul>
9974
9975
9976
9977
9978 
9979       
9980       
9981       
9982       
9983        <p><b>s_vertical_gradient</b>
9984= <i>0.1</i>, <i>0.05</i>,&nbsp; <br>
9985
9986
9987
9988
9989
9990        <b>s_vertical_gradient_level</b> = <i>500.0</i>,
9991        <i>1000.0</i>,</p>
9992
9993
9994
9995
9996 
9997     
9998     
9999     
10000     
10001      </ul>
10002
10003
10004
10005
10006 
10007     
10008     
10009     
10010     
10011      <p>That
10012defines the scalar concentration to be constant with
10013height up to z = 500.0 m with a value given by <a href="#s_surface">s_surface</a>.
10014For 500.0 m &lt; z &lt;= 1000.0 m the scalar gradient is 0.1
10015kg/m<sup>3 </sup>/ 100 m and for z &gt; 1000.0 m up to
10016the top
10017boundary it is 0.05 kg/m<sup>3 </sup>/ 100 m (it is
10018assumed that the
10019assigned height levels
10020correspond with uv
10021levels).</p>
10022
10023
10024
10025
10026 </td>
10027
10028
10029
10030
10031 </tr>
10032
10033
10034
10035
10036 <tr>
10037
10038
10039
10040
10041 <td style="vertical-align: top;"> 
10042     
10043     
10044     
10045     
10046      <p><a name="s_vertical_gradient_level"></a><b>s_vertical_gradient_</b>
10047      <br>
10048
10049
10050
10051
10052 <b>level</b></p>
10053
10054
10055
10056
10057 </td>
10058
10059
10060
10061
10062 <td style="vertical-align: top;">R (10)</td>
10063
10064
10065
10066
10067 <td style="vertical-align: top;"> 
10068     
10069     
10070     
10071     
10072      <p><i>10 *</i>
10073      <i>0.0</i></p>
10074
10075
10076
10077
10078 </td>
10079
10080
10081
10082
10083 <td style="vertical-align: top;"> 
10084     
10085     
10086     
10087     
10088      <p>Height level from
10089which on the scalar gradient defined by <a href="#s_vertical_gradient">s_vertical_gradient</a>
10090is effective (in m).&nbsp; </p>
10091
10092
10093
10094
10095 
10096     
10097     
10098     
10099     
10100      <p>The height levels
10101are to be assigned in ascending order. The
10102default values result in a scalar concentration constant with height
10103regardless of the values of <a href="#s_vertical_gradient">s_vertical_gradient</a>
10104(unless the top boundary of the model is higher than 100000.0 m). For
10105the
10106piecewise construction of scalar concentration profiles see <a href="#s_vertical_gradient">s_vertical_gradient</a>.</p>
10107
10108
10109
10110
10111
10112      </td>
10113
10114
10115
10116
10117 </tr>
10118
10119
10120
10121
10122 <tr>
10123
10124
10125
10126
10127 <td style="vertical-align: top;"> 
10128     
10129     
10130     
10131     
10132      <p><a name="timestep_scheme"></a><b>timestep_scheme</b></p>
10133
10134
10135
10136
10137
10138      </td>
10139
10140
10141
10142
10143 <td style="vertical-align: top;">C * 20</td>
10144
10145
10146
10147
10148
10149      <td style="vertical-align: top;"> 
10150     
10151     
10152     
10153     
10154      <p><i>'runge</i><br>
10155
10156
10157
10158
10159
10160      <i>kutta-3'</i></p>
10161
10162
10163
10164
10165 </td>
10166
10167
10168
10169
10170 <td style="vertical-align: top;"> 
10171     
10172     
10173     
10174     
10175      <p>Time step scheme to
10176be used for the integration of the prognostic
10177variables.&nbsp; </p>
10178
10179
10180
10181
10182 
10183     
10184     
10185     
10186     
10187      <p>The user can choose between
10188the following schemes:<br>
10189
10190
10191
10192
10193 </p>
10194
10195
10196
10197
10198 
10199     
10200     
10201     
10202     
10203      <p><span style="font-style: italic;">'runge-kutta-3'</span><br>
10204
10205
10206
10207
10208
10209      </p>
10210
10211
10212
10213
10214 
10215     
10216     
10217     
10218     
10219      <div style="margin-left: 40px;">Third order
10220Runge-Kutta scheme.<br>
10221
10222
10223
10224
10225
10226This scheme requires the use of <a href="#momentum_advec">momentum_advec</a>
10227= <a href="#scalar_advec">scalar_advec</a>
10228= '<i>pw-scheme'</i>. Please refer to the&nbsp;<a href="../tec/numerik.heiko/zeitschrittverfahren.pdf">documentation
10229on PALM's time integration schemes&nbsp;(28p., in German)</a>
10230fur further details.<br>
10231
10232
10233
10234
10235 </div>
10236
10237
10238
10239
10240 
10241     
10242     
10243     
10244     
10245      <p><span style="font-style: italic;">'runge-kutta-2'</span><br>
10246
10247
10248
10249
10250
10251      </p>
10252
10253
10254
10255
10256 
10257     
10258     
10259     
10260     
10261      <div style="margin-left: 40px;">Second order
10262Runge-Kutta scheme.<br>
10263
10264
10265
10266
10267
10268For special features see <b>timestep_scheme</b> = '<i>runge-kutta-3'</i>.<br>
10269
10270
10271
10272
10273
10274      </div>
10275
10276
10277
10278
10279 <br>
10280
10281
10282
10283
10284 <span style="font-style: italic;"><span style="font-style: italic;">'leapfrog'</span><br>
10285
10286
10287
10288
10289
10290      <br>
10291
10292
10293
10294
10295 </span> 
10296     
10297     
10298     
10299     
10300      <div style="margin-left: 40px;">Second
10301order leapfrog scheme.<br>
10302
10303
10304
10305
10306
10307Although this scheme requires a constant timestep (because it is
10308centered in time),&nbsp; is even applied in case of changes in
10309timestep. Therefore, only small
10310changes of the timestep are allowed (see <a href="#dt">dt</a>).
10311However, an Euler timestep is always used as the first timestep of an
10312initiali run. When using the Bott-Chlond scheme for scalar advection
10313(see <a href="#scalar_advec">scalar_advec</a>),
10314the prognostic equation for potential temperature will be calculated
10315with the Euler scheme, although the leapfrog scheme is switched
10316on.&nbsp; <br>
10317
10318
10319
10320
10321
10322The leapfrog scheme must not be used together with the upstream-spline
10323scheme for calculating the advection (see <a href="#scalar_advec">scalar_advec</a>
10324= '<i>ups-scheme'</i> and <a href="#momentum_advec">momentum_advec</a>
10325= '<i>ups-scheme'</i>).<br>
10326
10327
10328
10329
10330 </div>
10331
10332
10333
10334
10335 <br>
10336
10337
10338
10339
10340
10341      <span style="font-style: italic;">'</span><span style="font-style: italic;"><span style="font-style: italic;">leapfrog+euler'</span><br>
10342
10343
10344
10345
10346
10347      <br>
10348
10349
10350
10351
10352 </span> 
10353     
10354     
10355     
10356     
10357      <div style="margin-left: 40px;">The
10358leapfrog scheme is used, but
10359after each change of a timestep an Euler timestep is carried out.
10360Although this method is theoretically correct (because the pure
10361leapfrog method does not allow timestep changes), the divergence of the
10362velocity field (after applying the pressure solver) may be
10363significantly larger than with <span style="font-style: italic;">'leapfrog'</span>.<br>
10364
10365
10366
10367
10368
10369      </div>
10370
10371
10372
10373
10374 <br>
10375
10376
10377
10378
10379 <span style="font-style: italic;">'euler'</span><br>
10380
10381
10382
10383
10384
10385      <br>
10386
10387
10388
10389
10390 
10391     
10392     
10393     
10394     
10395      <div style="margin-left: 40px;">First order
10396Euler scheme.&nbsp; <br>
10397
10398
10399
10400
10401
10402The Euler scheme must be used when treating the advection terms with
10403the upstream-spline scheme (see <a href="#scalar_advec">scalar_advec</a>
10404= <span style="font-style: italic;">'ups-scheme'</span>
10405and <a href="#momentum_advec">momentum_advec</a>
10406= <span style="font-style: italic;">'ups-scheme'</span>).</div>
10407
10408
10409
10410
10411
10412      <br>
10413
10414
10415
10416
10417      <br>
10418
10419
10420
10421
10422A differing timestep scheme can be choosed for the
10423subgrid-scale TKE using parameter <a href="#use_upstream_for_tke">use_upstream_for_tke</a>.<br>
10424
10425
10426
10427
10428
10429      </td>
10430
10431
10432
10433
10434 </tr>
10435
10436
10437
10438
10439 <tr>
10440
10441
10442
10443
10444 <td style="text-align: left; vertical-align: top;"><span style="font-weight: bold;"><a name="topography"></a></span><span style="font-weight: bold;">topography</span></td>
10445
10446
10447
10448
10449
10450      <td style="vertical-align: top;">C * 40</td>
10451
10452
10453
10454
10455 <td style="vertical-align: top;"><span style="font-style: italic;">'flat'</span></td>
10456
10457
10458
10459
10460 <td>
10461     
10462     
10463     
10464     
10465      <p>Topography mode.&nbsp; </p>
10466
10467
10468
10469
10470 
10471     
10472     
10473     
10474     
10475      <p>The user can
10476choose between the following modes:<br>
10477
10478
10479
10480
10481 </p>
10482
10483
10484
10485
10486 
10487     
10488     
10489     
10490     
10491      <p><span style="font-style: italic;">'flat'</span><br>
10492
10493
10494