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22  <title>PALM chapter 4.1</title>
23</head>
24
25<body>
26
27
28
29
30<h3><a name="chapter4.1"></a>4.1
31Initialization parameters</h3>
32
33
34
35
36
37<br>
38
39
40
41
42<table style="text-align: left; width: 100%;" border="1" cellpadding="2" cellspacing="2">
43
44
45
46
47 <tbody>
48
49
50
51
52
53    <tr>
54
55
56
57
58 <td style="vertical-align: top;"><font size="4"><b>Parameter name</b></font></td>
59
60
61
62
63
64      <td style="vertical-align: top;"><font size="4"><b>Type</b></font></td>
65
66
67
68
69
70      <td style="vertical-align: top;"> 
71     
72     
73     
74     
75      <p><b><font size="4">Default</font></b> <br>
76
77
78
79
80 <b><font size="4">value</font></b></p>
81
82
83
84
85 </td>
86
87
88
89
90
91      <td style="vertical-align: top;"><font size="4"><b>Explanation</b></font></td>
92
93
94
95
96
97    </tr>
98
99
100
101
102 <tr>
103
104
105
106
107 <td style="vertical-align: top;">
108     
109     
110     
111     
112      <p><a name="adjust_mixing_length"></a><b>adjust_mixing_length</b></p>
113
114
115
116
117
118      </td>
119
120
121
122
123 <td style="vertical-align: top;">L</td>
124
125
126
127
128
129      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
130
131
132
133
134 <td style="vertical-align: top;"> 
135     
136     
137     
138     
139      <p style="font-style: normal;">Near-surface adjustment of the
140mixing length to the Prandtl-layer law.&nbsp; </p>
141
142
143
144
145 
146     
147     
148     
149     
150      <p>Usually
151the mixing length in LES models l<sub>LES</sub>
152depends (as in PALM) on the grid size and is possibly restricted
153further in case of stable stratification and near the lower wall (see
154parameter <a href="#wall_adjustment">wall_adjustment</a>).
155With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span>
156the Prandtl' mixing length l<sub>PR</sub> = kappa * z/phi
157is calculated
158and the mixing length actually used in the model is set l = MIN (l<sub>LES</sub>,
159l<sub>PR</sub>). This usually gives a decrease of the
160mixing length at
161the bottom boundary and considers the fact that eddy sizes
162decrease in the vicinity of the wall.&nbsp; </p>
163
164
165
166
167 
168     
169     
170     
171     
172      <p style="font-style: normal;"><b>Warning:</b> So
173far, there is
174no good experience with <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> !&nbsp; </p>
175
176
177
178
179
180     
181     
182     
183     
184      <p>With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> and the
185Prandtl-layer being
186switched on (see <a href="#prandtl_layer">prandtl_layer</a>)
187      <span style="font-style: italic;">'(u*)** 2+neumann'</span>
188should always be set as the lower boundary condition for the TKE (see <a href="#bc_e_b">bc_e_b</a>),
189otherwise the near-surface value of the TKE is not in agreement with
190the Prandtl-layer law (Prandtl-layer law and Prandtl-Kolmogorov-Ansatz
191should provide the same value for K<sub>m</sub>). A warning
192is given,
193if this is not the case.</p>
194
195
196
197
198 </td>
199
200
201
202
203 </tr>
204
205
206
207
208 <tr>
209
210
211
212
213
214      <td style="vertical-align: top;"> 
215     
216     
217     
218     
219      <p><a name="alpha_surface"></a><b>alpha_surface</b></p>
220
221
222
223
224
225      </td>
226
227
228
229
230 <td style="vertical-align: top;">R<br>
231
232
233
234
235 </td>
236
237
238
239
240
241      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
242
243
244
245
246 </td>
247
248
249
250
251
252      <td style="vertical-align: top;"> 
253     
254     
255     
256     
257      <p style="font-style: normal;">Inclination of the model domain
258with respect to the horizontal (in degrees).&nbsp; </p>
259
260
261
262
263 
264     
265     
266     
267     
268      <p style="font-style: normal;">By means of <b>alpha_surface</b>
269the model domain can be inclined in x-direction with respect to the
270horizontal. In this way flows over inclined surfaces (e.g. drainage
271flows, gravity flows) can be simulated. In case of <b>alpha_surface
272      </b>/= <span style="font-style: italic;">0</span>
273the buoyancy term
274appears both in
275the equation of motion of the u-component and of the w-component.<br>
276
277
278
279
280
281      </p>
282
283
284
285
286 
287     
288     
289     
290     
291      <p style="font-style: normal;">An inclination
292is only possible in
293case of cyclic horizontal boundary conditions along x AND y (see <a href="#bc_lr">bc_lr</a>
294and <a href="#bc_ns">bc_ns</a>) and <a href="#topography">topography</a> = <span style="font-style: italic;">'flat'</span>. </p>
295
296
297
298
299
300     
301     
302     
303     
304      <p>Runs with inclined surface still require additional
305user-defined code as well as modifications to the default code. Please
306ask the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/PALM_group.html#0">PALM
307developer&nbsp; group</a>.</p>
308
309
310
311
312 </td>
313
314
315
316
317 </tr>
318
319
320
321
322
323    <tr>
324
325
326
327
328 <td style="vertical-align: top;"> 
329     
330     
331     
332     
333      <p><a name="bc_e_b"></a><b>bc_e_b</b></p>
334
335
336
337
338 </td>
339
340
341
342
343
344      <td style="vertical-align: top;">C * 20</td>
345
346
347
348
349 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
350
351
352
353
354
355      <td style="vertical-align: top;"> 
356     
357     
358     
359     
360      <p style="font-style: normal;">Bottom boundary condition of the
361TKE.&nbsp; </p>
362
363
364
365
366 
367     
368     
369     
370     
371      <p><b>bc_e_b</b> may be
372set to&nbsp;<span style="font-style: italic;">'neumann'</span>
373or <span style="font-style: italic;">'(u*) ** 2+neumann'</span>.
374      <b>bc_e_b</b>
375= <span style="font-style: italic;">'neumann'</span>
376yields to
377e(k=0)=e(k=1) (Neumann boundary condition), where e(k=1) is calculated
378via the prognostic TKE equation. Choice of <span style="font-style: italic;">'(u*)**2+neumann'</span>
379also yields to
380e(k=0)=e(k=1), but the TKE at the Prandtl-layer top (k=1) is calculated
381diagnostically by e(k=1)=(us/0.1)**2. However, this is only allowed if
382a Prandtl-layer is used (<a href="#prandtl_layer">prandtl_layer</a>).
383If this is not the case, a warning is given and <b>bc_e_b</b>
384is reset
385to <span style="font-style: italic;">'neumann'</span>.&nbsp;
386      </p>
387
388
389
390
391 
392     
393     
394     
395     
396      <p style="font-style: normal;">At the top
397boundary a Neumann
398boundary condition is generally used: (e(nz+1) = e(nz)).</p>
399
400
401
402
403 </td>
404
405
406
407
408
409    </tr>
410
411
412
413
414 <tr>
415
416
417
418
419 <td style="vertical-align: top;">
420     
421     
422     
423     
424      <p><a name="bc_lr"></a><b>bc_lr</b></p>
425
426
427
428
429
430      </td>
431
432
433
434
435 <td style="vertical-align: top;">C * 20</td>
436
437
438
439
440
441      <td style="vertical-align: top;"><span style="font-style: italic;">'cyclic'</span></td>
442
443
444
445
446
447      <td style="vertical-align: top;">Boundary
448condition along x (for all quantities).<br>
449
450
451
452
453 <br>
454
455
456
457
458
459By default, a cyclic boundary condition is used along x.<br>
460
461
462
463
464 <br>
465
466
467
468
469
470      <span style="font-weight: bold;">bc_lr</span> may
471also be
472assigned the values <span style="font-style: italic;">'dirichlet/radiation'</span>
473(inflow from left, outflow to the right) or <span style="font-style: italic;">'radiation/dirichlet'</span>
474(inflow from
475right, outflow to the left). This requires the multi-grid method to be
476used 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>)
477and it also requires cyclic boundary conditions along y (see&nbsp;<a href="#bc_ns">bc_ns</a>).<br>
478
479
480
481
482 <br>
483
484
485
486
487
488In case of these non-cyclic lateral boundaries, a Dirichlet condition
489is used at the inflow for all quantities (initial vertical profiles -
490see <a href="#initializing_actions">initializing_actions</a>
491- are fixed during the run) except u, to which a Neumann (zero
492gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
493gradient) condition is used for the scalars. For perturbation
494pressure Neumann (zero gradient) conditions are assumed both at the
495inflow and at the outflow.<br>
496
497
498
499
500 <br>
501
502
503
504
505
506When using non-cyclic lateral boundaries, a filter is applied to the
507velocity field in the vicinity of the outflow in order to suppress any
508reflections of outgoing disturbances (see <a href="#km_damp_max">km_damp_max</a>
509and <a href="#outflow_damping_width">outflow_damping_width</a>).<br>
510
511
512
513
514
515      <br>
516
517
518
519
520
521In order to maintain a turbulent state of the flow, it may be
522neccessary to continuously impose perturbations on the horizontal
523velocity field in the vicinity of the inflow throughout the whole run.
524This 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>.
525The horizontal range to which these perturbations are applied is
526controlled by the parameters <a href="#inflow_disturbance_begin">inflow_disturbance_begin</a>
527and <a href="#inflow_disturbance_end">inflow_disturbance_end</a>.
528The 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>,
529      <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_level_t</a>,
530and <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_amplitude</a>.
531The 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>
532
533
534
535
536
537      <br>
538
539
540
541
542
543In 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
544at_all_substeps</a> = .T. should be used.<br>
545
546
547
548
549 <br>
550
551
552
553
554 <span style="font-weight: bold;">Note:</span><br>
555
556
557
558
559
560Using non-cyclic lateral boundaries requires very sensitive adjustments
561of the inflow (vertical profiles) and the bottom boundary conditions,
562e.g. a surface heating should not be applied near the inflow boundary
563because this may significantly disturb the inflow. Please check the
564model results very carefully.</td>
565
566
567
568
569 </tr>
570
571
572
573
574 <tr>
575
576
577
578
579 <td style="vertical-align: top;"> 
580     
581     
582     
583     
584      <p><a name="bc_ns"></a><b>bc_ns</b></p>
585
586
587
588
589
590      </td>
591
592
593
594
595 <td style="vertical-align: top;">C * 20</td>
596
597
598
599
600
601      <td style="vertical-align: top;"><span style="font-style: italic;">'cyclic'</span></td>
602
603
604
605
606
607      <td style="vertical-align: top;">Boundary
608condition along y (for all quantities).<br>
609
610
611
612
613 <br>
614
615
616
617
618
619By default, a cyclic boundary condition is used along y.<br>
620
621
622
623
624 <br>
625
626
627
628
629
630      <span style="font-weight: bold;">bc_ns</span> may
631also be
632assigned the values <span style="font-style: italic;">'dirichlet/radiation'</span>
633(inflow from rear ("north"), outflow to the front ("south")) or <span style="font-style: italic;">'radiation/dirichlet'</span>
634(inflow from front ("south"), outflow to the rear ("north")). This
635requires the multi-grid
636method to be used for solving the Poisson equation for perturbation
637pressure (see <a href="chapter_4.2.html#psolver">psolver</a>)
638and it also requires cyclic boundary conditions along x (see<br>
639
640
641
642
643 <a href="#bc_lr">bc_lr</a>).<br>
644
645
646
647
648 <br>
649
650
651
652
653
654In case of these non-cyclic lateral boundaries, a Dirichlet condition
655is used at the inflow for all quantities (initial vertical profiles -
656see <a href="chapter_4.1.html#initializing_actions">initializing_actions</a>
657- are fixed during the run) except u, to which a Neumann (zero
658gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
659gradient) condition is used for the scalars. For perturbation
660pressure Neumann (zero gradient) conditions are assumed both at the
661inflow and at the outflow.<br>
662
663
664
665
666 <br>
667
668
669
670
671
672For further details regarding non-cyclic lateral boundary conditions
673see <a href="#bc_lr">bc_lr</a>.</td>
674
675
676
677
678 </tr>
679
680
681
682
683
684    <tr>
685
686
687
688
689 <td style="vertical-align: top;"> 
690     
691     
692     
693     
694      <p><a name="bc_p_b"></a><b>bc_p_b</b></p>
695
696
697
698
699 </td>
700
701
702
703
704
705      <td style="vertical-align: top;">C * 20</td>
706
707
708
709
710 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
711
712
713
714
715
716      <td style="vertical-align: top;"> 
717     
718     
719     
720     
721      <p style="font-style: normal;">Bottom boundary condition of the
722perturbation pressure.&nbsp; </p>
723
724
725
726
727 
728     
729     
730     
731     
732      <p>Allowed values
733are <span style="font-style: italic;">'dirichlet'</span>,
734      <span style="font-style: italic;">'neumann'</span>
735and <span style="font-style: italic;">'neumann+inhomo'</span>.&nbsp;
736      <span style="font-style: italic;">'dirichlet'</span>
737sets
738p(k=0)=0.0,&nbsp; <span style="font-style: italic;">'neumann'</span>
739sets p(k=0)=p(k=1). <span style="font-style: italic;">'neumann+inhomo'</span>
740corresponds to an extended Neumann boundary condition where heat flux
741or temperature inhomogeneities near the
742surface (pt(k=1))&nbsp; are additionally regarded (see Shen and
743LeClerc
744(1995, Q.J.R. Meteorol. Soc.,
7451209)). This condition is only permitted with the Prandtl-layer
746switched on (<a href="#prandtl_layer">prandtl_layer</a>),
747otherwise the run is terminated.&nbsp; </p>
748
749
750
751
752 
753     
754     
755     
756     
757      <p>Since
758at the bottom boundary of the model the vertical
759velocity
760disappears (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>)
761dp/dz = 0 should
762be used, which leaves the vertical component w unchanged when the
763pressure solver is applied. Simultaneous use of the Neumann boundary
764conditions both at the bottom and at the top boundary (<a href="#bc_p_t">bc_p_t</a>)
765usually yields no consistent solution for the perturbation pressure and
766should be avoided.</p>
767
768
769
770
771 </td>
772
773
774
775
776 </tr>
777
778
779
780
781 <tr>
782
783
784
785
786 <td style="vertical-align: top;"> 
787     
788     
789     
790     
791      <p><a name="bc_p_t"></a><b>bc_p_t</b></p>
792
793
794
795
796
797      </td>
798
799
800
801
802 <td style="vertical-align: top;">C * 20</td>
803
804
805
806
807
808      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
809
810
811
812
813
814      <td style="vertical-align: top;"> 
815     
816     
817     
818     
819      <p style="font-style: normal;">Top boundary condition of the
820perturbation pressure.&nbsp; </p>
821
822
823
824
825 
826     
827     
828     
829     
830      <p style="font-style: normal;">Allowed values are <span style="font-style: italic;">'dirichlet'</span>
831(p(k=nz+1)= 0.0) or <span style="font-style: italic;">'neumann'</span>
832(p(k=nz+1)=p(k=nz)).&nbsp; </p>
833
834
835
836
837 
838     
839     
840     
841     
842      <p>Simultaneous use
843of Neumann boundary conditions both at the
844top and bottom boundary (<a href="#bc_p_b">bc_p_b</a>)
845usually yields no consistent solution for the perturbation pressure and
846should be avoided. Since at the bottom boundary the Neumann
847condition&nbsp; is a good choice (see <a href="#bc_p_b">bc_p_b</a>),
848a Dirichlet condition should be set at the top boundary.</p>
849
850
851
852
853 </td>
854
855
856
857
858
859    </tr>
860
861
862
863
864 <tr>
865
866
867
868
869 <td style="vertical-align: top;">
870     
871     
872     
873     
874      <p><a name="bc_pt_b"></a><b>bc_pt_b</b></p>
875
876
877
878
879
880      </td>
881
882
883
884
885 <td style="vertical-align: top;">C*20</td>
886
887
888
889
890
891      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
892
893
894
895
896
897      <td style="vertical-align: top;"> 
898     
899     
900     
901     
902      <p style="font-style: normal;">Bottom boundary condition of the
903potential temperature.&nbsp; </p>
904
905
906
907
908 
909     
910     
911     
912     
913      <p>Allowed values
914are <span style="font-style: italic;">'dirichlet'</span>
915(pt(k=0) = const. = <a href="#pt_surface">pt_surface</a>
916+ <a href="#pt_surface_initial_change">pt_surface_initial_change</a>;
917the user may change this value during the run using user-defined code)
918and <span style="font-style: italic;">'neumann'</span>
919(pt(k=0)=pt(k=1)).&nbsp; <br>
920
921
922
923
924
925When a constant surface sensible heat flux is used (<a href="#surface_heatflux">surface_heatflux</a>), <b>bc_pt_b</b>
926= <span style="font-style: italic;">'neumann'</span>
927must be used, because otherwise the resolved scale may contribute to
928the surface flux so that a constant value cannot be guaranteed.</p>
929
930
931
932
933     
934     
935     
936     
937      <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>
938
939
940
941
942
943      </td>
944
945
946
947
948 </tr>
949
950
951
952
953 <tr>
954
955
956
957
958 <td style="vertical-align: top;"> 
959     
960     
961     
962     
963      <p><a name="pc_pt_t"></a><b>bc_pt_t</b></p>
964
965
966
967
968
969      </td>
970
971
972
973
974 <td style="vertical-align: top;">C * 20</td>
975
976
977
978
979
980      <td style="vertical-align: top;"><span style="font-style: italic;">'initial_ gradient'</span></td>
981
982
983
984
985
986      <td style="vertical-align: top;"> 
987     
988     
989     
990     
991      <p style="font-style: normal;">Top boundary condition of the
992potential temperature.&nbsp; </p>
993
994
995
996
997 
998     
999     
1000     
1001     
1002      <p>Allowed are the
1003values <span style="font-style: italic;">'dirichlet' </span>(pt(k=nz+1)
1004does not change during the run), <span style="font-style: italic;">'neumann'</span>
1005(pt(k=nz+1)=pt(k=nz)), and <span style="font-style: italic;">'initial_gradient'</span>.
1006With the 'initial_gradient'-condition the value of the temperature
1007gradient at the top is
1008calculated from the initial
1009temperature profile (see <a href="#pt_surface">pt_surface</a>,
1010      <a href="#pt_vertical_gradient">pt_vertical_gradient</a>)
1011by bc_pt_t_val = (pt_init(k=nz+1) -
1012pt_init(k=nz)) / dzu(nz+1).<br>
1013
1014
1015
1016
1017
1018Using this value (assumed constant during the
1019run) the temperature boundary values are calculated as&nbsp; </p>
1020
1021
1022
1023
1024
1025     
1026     
1027     
1028     
1029      <ul>
1030
1031
1032
1033
1034 
1035       
1036       
1037       
1038       
1039        <p style="font-style: normal;">pt(k=nz+1) =
1040pt(k=nz) +
1041bc_pt_t_val * dzu(nz+1)</p>
1042
1043
1044
1045
1046 
1047     
1048     
1049     
1050     
1051      </ul>
1052
1053
1054
1055
1056 
1057     
1058     
1059     
1060     
1061      <p style="font-style: normal;">(up to k=nz the prognostic
1062equation for the temperature is solved).<br>
1063
1064
1065
1066
1067
1068When a constant sensible heat flux is used at the top boundary (<a href="chapter_4.1.html#top_heatflux">top_heatflux</a>),
1069      <b>bc_pt_t</b> = <span style="font-style: italic;">'neumann'</span>
1070must be used, because otherwise the resolved scale may contribute to
1071the top flux so that a constant value cannot be guaranteed.</p>
1072
1073
1074
1075
1076 </td>
1077
1078
1079
1080
1081
1082    </tr>
1083
1084
1085
1086
1087 <tr>
1088
1089
1090
1091
1092 <td style="vertical-align: top;">
1093     
1094     
1095     
1096     
1097      <p><a name="bc_q_b"></a><b>bc_q_b</b></p>
1098
1099
1100
1101
1102
1103      </td>
1104
1105
1106
1107
1108 <td style="vertical-align: top;">C * 20</td>
1109
1110
1111
1112
1113
1114      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1115
1116
1117
1118
1119
1120      <td style="vertical-align: top;"> 
1121     
1122     
1123     
1124     
1125      <p style="font-style: normal;">Bottom boundary condition of the
1126specific humidity / total water content.&nbsp; </p>
1127
1128
1129
1130
1131 
1132     
1133     
1134     
1135     
1136      <p>Allowed
1137values are <span style="font-style: italic;">'dirichlet'</span>
1138(q(k=0) = const. = <a href="#q_surface">q_surface</a>
1139+ <a href="#q_surface_initial_change">q_surface_initial_change</a>;
1140the user may change this value during the run using user-defined code)
1141and <span style="font-style: italic;">'neumann'</span>
1142(q(k=0)=q(k=1)).&nbsp; <br>
1143
1144
1145
1146
1147
1148When a constant surface latent heat flux is used (<a href="#surface_waterflux">surface_waterflux</a>), <b>bc_q_b</b>
1149= <span style="font-style: italic;">'neumann'</span>
1150must be used, because otherwise the resolved scale may contribute to
1151the surface flux so that a constant value cannot be guaranteed.</p>
1152
1153
1154
1155
1156
1157      </td>
1158
1159
1160
1161
1162 </tr>
1163
1164
1165
1166
1167 <tr>
1168
1169
1170
1171
1172 <td style="vertical-align: top;"> 
1173     
1174     
1175     
1176     
1177      <p><a name="bc_q_t"></a><b>bc_q_t</b></p>
1178
1179
1180
1181
1182
1183      </td>
1184
1185
1186
1187
1188 <td style="vertical-align: top;"><span style="font-style: italic;">C
1189* 20</span></td>
1190
1191
1192
1193
1194 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1195
1196
1197
1198
1199
1200      <td style="vertical-align: top;"> 
1201     
1202     
1203     
1204     
1205      <p style="font-style: normal;">Top boundary condition of the
1206specific humidity / total water content.&nbsp; </p>
1207
1208
1209
1210
1211 
1212     
1213     
1214     
1215     
1216      <p>Allowed
1217are the values <span style="font-style: italic;">'dirichlet'</span>
1218(q(k=nz) and q(k=nz+1) do
1219not change during the run) and <span style="font-style: italic;">'neumann'</span>.
1220With the Neumann boundary
1221condition the value of the humidity gradient at the top is calculated
1222from the
1223initial humidity profile (see <a href="#q_surface">q_surface</a>,
1224      <a href="#q_vertical_gradient">q_vertical_gradient</a>)
1225by: bc_q_t_val = ( q_init(k=nz) - q_init(k=nz-1)) / dzu(nz).<br>
1226
1227
1228
1229
1230
1231Using this value (assumed constant during the run) the humidity
1232boundary values
1233are calculated as&nbsp; </p>
1234
1235
1236
1237
1238 
1239     
1240     
1241     
1242     
1243      <ul>
1244
1245
1246
1247
1248 
1249       
1250       
1251       
1252       
1253        <p style="font-style: normal;">q(k=nz+1) =q(k=nz) +
1254bc_q_t_val * dzu(nz+1)</p>
1255
1256
1257
1258
1259 
1260     
1261     
1262     
1263     
1264      </ul>
1265
1266
1267
1268
1269 
1270     
1271     
1272     
1273     
1274      <p style="font-style: normal;">(up tp k=nz the prognostic
1275equation for q is solved). </p>
1276
1277
1278
1279
1280 </td>
1281
1282
1283
1284
1285 </tr>
1286
1287
1288
1289
1290 <tr>
1291
1292
1293
1294
1295
1296      <td style="vertical-align: top;"> 
1297     
1298     
1299     
1300     
1301      <p><a name="bc_s_b"></a><b>bc_s_b</b></p>
1302
1303
1304
1305
1306 </td>
1307
1308
1309
1310
1311
1312      <td style="vertical-align: top;">C * 20</td>
1313
1314
1315
1316
1317 <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1318
1319
1320
1321
1322
1323      <td style="vertical-align: top;"> 
1324     
1325     
1326     
1327     
1328      <p style="font-style: normal;">Bottom boundary condition of the
1329scalar concentration.&nbsp; </p>
1330
1331
1332
1333
1334 
1335     
1336     
1337     
1338     
1339      <p>Allowed values
1340are <span style="font-style: italic;">'dirichlet'</span>
1341(s(k=0) = const. = <a href="#s_surface">s_surface</a>
1342+ <a href="#s_surface_initial_change">s_surface_initial_change</a>;
1343the user may change this value during the run using user-defined code)
1344and <span style="font-style: italic;">'neumann'</span>
1345(s(k=0) =
1346s(k=1)).&nbsp; <br>
1347
1348
1349
1350
1351
1352When a constant surface concentration flux is used (<a href="#surface_scalarflux">surface_scalarflux</a>), <b>bc_s_b</b>
1353= <span style="font-style: italic;">'neumann'</span>
1354must be used, because otherwise the resolved scale may contribute to
1355the surface flux so that a constant value cannot be guaranteed.</p>
1356
1357
1358
1359
1360
1361      </td>
1362
1363
1364
1365
1366 </tr>
1367
1368
1369
1370
1371 <tr>
1372
1373
1374
1375
1376 <td style="vertical-align: top;"> 
1377     
1378     
1379     
1380     
1381      <p><a name="bc_s_t"></a><b>bc_s_t</b></p>
1382
1383
1384
1385
1386
1387      </td>
1388
1389
1390
1391
1392 <td style="vertical-align: top;">C * 20</td>
1393
1394
1395
1396
1397
1398      <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1399
1400
1401
1402
1403
1404      <td style="vertical-align: top;"> 
1405     
1406     
1407     
1408     
1409      <p style="font-style: normal;">Top boundary condition of the
1410scalar concentration.&nbsp; </p>
1411
1412
1413
1414
1415 
1416     
1417     
1418     
1419     
1420      <p>Allowed are the
1421values <span style="font-style: italic;">'dirichlet'</span>
1422(s(k=nz) and s(k=nz+1) do
1423not change during the run) and <span style="font-style: italic;">'neumann'</span>.
1424With the Neumann boundary
1425condition the value of the scalar concentration gradient at the top is
1426calculated
1427from the initial scalar concentration profile (see <a href="#s_surface">s_surface</a>, <a href="#s_vertical_gradient">s_vertical_gradient</a>)
1428by: bc_s_t_val = (s_init(k=nz) - s_init(k=nz-1)) / dzu(nz).<br>
1429
1430
1431
1432
1433
1434Using this value (assumed constant during the run) the concentration
1435boundary values
1436are calculated as </p>
1437
1438
1439
1440
1441 
1442     
1443     
1444     
1445     
1446      <ul>
1447
1448
1449
1450
1451 
1452       
1453       
1454       
1455       
1456        <p style="font-style: normal;">s(k=nz+1) = s(k=nz) +
1457bc_s_t_val * dzu(nz+1)</p>
1458
1459
1460
1461
1462 
1463     
1464     
1465     
1466     
1467      </ul>
1468
1469
1470
1471
1472 
1473     
1474     
1475     
1476     
1477      <p style="font-style: normal;">(up to k=nz the prognostic
1478equation for the scalar concentration is
1479solved).</p>
1480
1481
1482
1483
1484 </td>
1485
1486
1487
1488
1489 </tr>
1490
1491
1492
1493
1494 <tr>
1495
1496
1497
1498
1499      <td style="vertical-align: top;"><a name="bc_sa_t"></a><span style="font-weight: bold;">bc_sa_t</span></td>
1500
1501
1502
1503
1504      <td style="vertical-align: top;">C * 20</td>
1505
1506
1507
1508
1509      <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1510
1511
1512
1513
1514      <td style="vertical-align: top;">
1515     
1516     
1517     
1518     
1519      <p style="font-style: normal;">Top boundary condition of the salinity.&nbsp; </p>
1520
1521
1522
1523
1524 
1525     
1526     
1527     
1528     
1529      <p>This parameter only comes into effect for ocean runs (see parameter <a href="#ocean">ocean</a>).</p>
1530
1531
1532
1533
1534     
1535     
1536     
1537     
1538      <p style="font-style: normal;">Allowed are the
1539values <span style="font-style: italic;">'dirichlet' </span>(sa(k=nz+1)
1540does not change during the run) and <span style="font-style: italic;">'neumann'</span>
1541(sa(k=nz+1)=sa(k=nz))<span style="font-style: italic;"></span>.&nbsp;<br>
1542
1543
1544
1545
1546      <br>
1547
1548
1549
1550
1551
1552When a constant salinity flux is used at the top boundary (<a href="chapter_4.1.html#top_salinityflux">top_salinityflux</a>),
1553      <b>bc_sa_t</b> = <span style="font-style: italic;">'neumann'</span>
1554must be used, because otherwise the resolved scale may contribute to
1555the top flux so that a constant value cannot be guaranteed.</p>
1556
1557
1558
1559
1560      </td>
1561
1562
1563
1564
1565    </tr>
1566
1567
1568
1569
1570    <tr>
1571
1572
1573
1574
1575 <td style="vertical-align: top;"> 
1576     
1577     
1578     
1579     
1580      <p><a name="bc_uv_b"></a><b>bc_uv_b</b></p>
1581
1582
1583
1584
1585
1586      </td>
1587
1588
1589
1590
1591 <td style="vertical-align: top;">C * 20</td>
1592
1593
1594
1595
1596
1597      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1598
1599
1600
1601
1602
1603      <td style="vertical-align: top;"> 
1604     
1605     
1606     
1607     
1608      <p style="font-style: normal;">Bottom boundary condition of the
1609horizontal velocity components u and v.&nbsp; </p>
1610
1611
1612
1613
1614 
1615     
1616     
1617     
1618     
1619      <p>Allowed
1620values are <span style="font-style: italic;">'dirichlet' </span>and
1621      <span style="font-style: italic;">'neumann'</span>. <b>bc_uv_b</b>
1622= <span style="font-style: italic;">'dirichlet'</span>
1623yields the
1624no-slip condition with u=v=0 at the bottom. Due to the staggered grid
1625u(k=0) and v(k=0) are located at z = - 0,5 * <a href="#dz">dz</a>
1626(below the bottom), while u(k=1) and v(k=1) are located at z = +0,5 *
1627dz. u=v=0 at the bottom is guaranteed using mirror boundary
1628condition:&nbsp; </p>
1629
1630
1631
1632
1633 
1634     
1635     
1636     
1637     
1638      <ul>
1639
1640
1641
1642
1643 
1644       
1645       
1646       
1647       
1648        <p style="font-style: normal;">u(k=0) = - u(k=1) and v(k=0) = -
1649v(k=1)</p>
1650
1651
1652
1653
1654 
1655     
1656     
1657     
1658     
1659      </ul>
1660
1661
1662
1663
1664 
1665     
1666     
1667     
1668     
1669      <p style="font-style: normal;">The
1670Neumann boundary condition
1671yields the free-slip condition with u(k=0) = u(k=1) and v(k=0) =
1672v(k=1).
1673With Prandtl - layer switched on, the free-slip condition is not
1674allowed (otherwise the run will be terminated)<font color="#000000">.</font></p>
1675
1676
1677
1678
1679
1680      </td>
1681
1682
1683
1684
1685 </tr>
1686
1687
1688
1689
1690 <tr>
1691
1692
1693
1694
1695 <td style="vertical-align: top;"> 
1696     
1697     
1698     
1699     
1700      <p><a name="bc_uv_t"></a><b>bc_uv_t</b></p>
1701
1702
1703
1704
1705
1706      </td>
1707
1708
1709
1710
1711 <td style="vertical-align: top;">C * 20</td>
1712
1713
1714
1715
1716
1717      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1718
1719
1720
1721
1722
1723      <td style="vertical-align: top;"> 
1724     
1725     
1726     
1727     
1728      <p style="font-style: normal;">Top boundary condition of the
1729horizontal velocity components u and v.&nbsp; </p>
1730
1731
1732
1733
1734 
1735     
1736     
1737     
1738     
1739      <p>Allowed
1740values are <span style="font-style: italic;">'dirichlet'</span>
1741and <span style="font-style: italic;">'neumann'</span>.
1742The
1743Dirichlet condition yields u(k=nz+1) = ug(nz+1) and v(k=nz+1) =
1744vg(nz+1),
1745Neumann condition yields the free-slip condition with u(k=nz+1) =
1746u(k=nz) and v(k=nz+1) = v(k=nz) (up to k=nz the prognostic equations
1747for the velocities are solved).</p>
1748
1749
1750
1751
1752     
1753     
1754     
1755     
1756      <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>
1757
1758
1759
1760
1761 </td>
1762
1763
1764
1765
1766 </tr>
1767
1768
1769
1770
1771 <tr>
1772
1773
1774
1775
1776      <td style="vertical-align: top;"><a name="bottom_salinityflux"></a><span style="font-weight: bold;">bottom_salinityflux</span></td>
1777
1778
1779
1780
1781      <td style="vertical-align: top;">R</td>
1782
1783
1784
1785
1786      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
1787
1788
1789
1790
1791      <td style="vertical-align: top;">
1792     
1793     
1794     
1795     
1796      <p>Kinematic salinity flux near the surface (in psu m/s).&nbsp;</p>
1797
1798
1799
1800
1801This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).
1802     
1803     
1804     
1805     
1806      <p>The
1807respective salinity flux value is used
1808as bottom (horizontally homogeneous) boundary condition for the salinity equation. This additionally requires that a Neumann
1809condition must be used for the salinity, which is currently the only available condition.<br>
1810
1811
1812
1813
1814 </p>
1815
1816
1817
1818
1819 </td>
1820
1821
1822
1823
1824    </tr>
1825
1826
1827
1828
1829    <tr>
1830
1831
1832
1833
1834
1835      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_height"></a>building_height</span></td>
1836
1837
1838
1839
1840
1841      <td style="vertical-align: top;">R</td>
1842
1843
1844
1845
1846 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1847
1848
1849
1850
1851 <td>Height
1852of a single building in m.<br>
1853
1854
1855
1856
1857 <br>
1858
1859
1860
1861
1862 <span style="font-weight: bold;">building_height</span> must
1863be less than the height of the model domain. This parameter requires
1864the use of&nbsp;<a href="#topography">topography</a>
1865= <span style="font-style: italic;">'single_building'</span>.</td>
1866
1867
1868
1869
1870
1871    </tr>
1872
1873
1874
1875
1876 <tr>
1877
1878
1879
1880
1881 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_length_x"></a>building_length_x</span></td>
1882
1883
1884
1885
1886
1887      <td style="vertical-align: top;">R</td>
1888
1889
1890
1891
1892 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1893
1894
1895
1896
1897 <td><span style="font-style: italic;"></span>Width of a single
1898building in m.<br>
1899
1900
1901
1902
1903 <br>
1904
1905
1906
1907
1908
1909Currently, <span style="font-weight: bold;">building_length_x</span>
1910must be at least <span style="font-style: italic;">3
1911*&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>
1912      </span><span style="font-style: italic;">- <a href="#building_wall_left">building_wall_left</a></span>.
1913This parameter requires the use of&nbsp;<a href="#topography">topography</a>
1914= <span style="font-style: italic;">'single_building'</span>.</td>
1915
1916
1917
1918
1919
1920    </tr>
1921
1922
1923
1924
1925 <tr>
1926
1927
1928
1929
1930 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_length_y"></a>building_length_y</span></td>
1931
1932
1933
1934
1935
1936      <td style="vertical-align: top;">R</td>
1937
1938
1939
1940
1941 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1942
1943
1944
1945
1946 <td>Depth
1947of a single building in m.<br>
1948
1949
1950
1951
1952 <br>
1953
1954
1955
1956
1957
1958Currently, <span style="font-weight: bold;">building_length_y</span>
1959must be at least <span style="font-style: italic;">3
1960*&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
1961the use of&nbsp;<a href="#topography">topography</a>
1962= <span style="font-style: italic;">'single_building'</span>.</td>
1963
1964
1965
1966
1967
1968    </tr>
1969
1970
1971
1972
1973 <tr>
1974
1975
1976
1977
1978 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_wall_left"></a>building_wall_left</span></td>
1979
1980
1981
1982
1983
1984      <td style="vertical-align: top;">R</td>
1985
1986
1987
1988
1989 <td style="vertical-align: top;"><span style="font-style: italic;">building centered in x-direction</span></td>
1990
1991
1992
1993
1994
1995      <td>x-coordinate of the left building wall (distance between the
1996left building wall and the left border of the model domain) in m.<br>
1997
1998
1999
2000
2001
2002      <br>
2003
2004
2005
2006
2007
2008Currently, <span style="font-weight: bold;">building_wall_left</span>
2009must be at least <span style="font-style: italic;">1
2010*&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;
2011- 1 ) * <a href="#dx">dx</a> -&nbsp; <a href="#building_length_x">building_length_x</a></span>.
2012This parameter requires the use of&nbsp;<a href="#topography">topography</a>
2013= <span style="font-style: italic;">'single_building'</span>.<br>
2014
2015
2016
2017
2018
2019      <br>
2020
2021
2022
2023
2024
2025The default value&nbsp;<span style="font-weight: bold;">building_wall_left</span>
2026= <span style="font-style: italic;">( ( <a href="#nx">nx</a>&nbsp;+
20271 ) * <a href="#dx">dx</a> -&nbsp; <a href="#building_length_x">building_length_x</a> ) / 2</span>
2028centers the building in x-direction. </td>
2029
2030
2031
2032
2033 </tr>
2034
2035
2036
2037
2038 <tr>
2039
2040
2041
2042
2043
2044      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_wall_south"></a>building_wall_south</span></td>
2045
2046
2047
2048
2049
2050      <td style="vertical-align: top;">R</td>
2051
2052
2053
2054
2055 <td style="vertical-align: top;"><span style="font-style: italic;"></span><span style="font-style: italic;">building centered in y-direction</span></td>
2056
2057
2058
2059
2060
2061      <td>y-coordinate of the South building wall (distance between the
2062South building wall and the South border of the model domain) in m.<br>
2063
2064
2065
2066
2067
2068      <br>
2069
2070
2071
2072
2073
2074Currently, <span style="font-weight: bold;">building_wall_south</span>
2075must be at least <span style="font-style: italic;">1
2076*&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;
2077- 1 ) * <a href="#dy">dy</a> -&nbsp; <a href="#building_length_y">building_length_y</a></span>.
2078This parameter requires the use of&nbsp;<a href="#topography">topography</a>
2079= <span style="font-style: italic;">'single_building'</span>.<br>
2080
2081
2082
2083
2084
2085      <br>
2086
2087
2088
2089
2090
2091The default value&nbsp;<span style="font-weight: bold;">building_wall_south</span>
2092= <span style="font-style: italic;">( ( <a href="#ny">ny</a>&nbsp;+
20931 ) * <a href="#dy">dy</a> -&nbsp; <a href="#building_length_y">building_length_y</a> ) / 2</span>
2094centers the building in y-direction. </td>
2095
2096
2097
2098
2099 </tr>
2100
2101
2102
2103
2104 <tr>
2105
2106
2107
2108
2109
2110      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="cloud_droplets"></a>cloud_droplets</span><br>
2111
2112
2113
2114
2115
2116      </td>
2117
2118
2119
2120
2121 <td style="vertical-align: top;">L<br>
2122
2123
2124
2125
2126 </td>
2127
2128
2129
2130
2131
2132      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span><br>
2133
2134
2135
2136
2137 </td>
2138
2139
2140
2141
2142
2143      <td style="vertical-align: top;">Parameter to switch on
2144usage of cloud droplets.<br>
2145
2146
2147
2148
2149 <br>
2150
2151
2152
2153
2154
2155Cloud droplets require to use the particle package (<span style="font-weight: bold;">mrun</span>-option <span style="font-family: monospace;">-p particles</span>),
2156so in this case a particle corresponds to a droplet. The droplet
2157features (number of droplets, initial radius, etc.) can be steered with
2158the&nbsp; respective particle parameters (see e.g. <a href="#chapter_4.2.html#radius">radius</a>).
2159The real number of initial droplets in a grid cell is equal to the
2160initial 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>
2161      <span lang="en-GB"><font face="Thorndale, serif">and
2162      </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>)
2163times the <a href="#initial_weighting_factor">initial_weighting_factor</a>.<br>
2164
2165
2166
2167
2168
2169      <br>
2170
2171
2172
2173
2174
2175In case of using cloud droplets, the default condensation scheme in
2176PALM cannot be used, i.e. <a href="#cloud_physics">cloud_physics</a>
2177must be set <span style="font-style: italic;">.F.</span>.<br>
2178
2179
2180
2181
2182
2183      </td>
2184
2185
2186
2187
2188 </tr>
2189
2190
2191
2192
2193 <tr>
2194
2195
2196
2197
2198 <td style="vertical-align: top;"> 
2199     
2200     
2201     
2202     
2203      <p><a name="cloud_physics"></a><b>cloud_physics</b></p>
2204
2205
2206
2207
2208
2209      </td>
2210
2211
2212
2213
2214 <td style="vertical-align: top;">L<br>
2215
2216
2217
2218
2219 </td>
2220
2221
2222
2223
2224
2225      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
2226
2227
2228
2229
2230 <td style="vertical-align: top;"> 
2231     
2232     
2233     
2234     
2235      <p>Parameter to switch
2236on the condensation scheme.&nbsp; </p>
2237
2238
2239
2240
2241
2242For <b>cloud_physics =</b> <span style="font-style: italic;">.TRUE.</span>, equations
2243for the
2244liquid water&nbsp;
2245content and the liquid water potential temperature are solved instead
2246of those for specific humidity and potential temperature. Note
2247that a grid volume is assumed to be either completely saturated or
2248completely
2249unsaturated (0%-or-100%-scheme). A simple precipitation scheme can
2250additionally be switched on with parameter <a href="#precipitation">precipitation</a>.
2251Also cloud-top cooling by longwave radiation can be utilized (see <a href="#radiation">radiation</a>)<br>
2252
2253
2254
2255
2256 <b><br>
2257
2258
2259
2260
2261
2262cloud_physics =</b> <span style="font-style: italic;">.TRUE.
2263      </span>requires&nbsp;<a href="#humidity">humidity</a>
2264=<span style="font-style: italic;"> .TRUE.</span> .<br>
2265
2266
2267
2268
2269
2270Detailed information about the condensation scheme is given in the
2271description of the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM-1/Dokumentationen/Cloud_physics/wolken.pdf">cloud
2272physics module</a> (pdf-file, only in German).<br>
2273
2274
2275
2276
2277 <br>
2278
2279
2280
2281
2282
2283This condensation scheme is not allowed if cloud droplets are simulated
2284explicitly (see <a href="#cloud_droplets">cloud_droplets</a>).<br>
2285
2286
2287
2288
2289
2290      </td>
2291
2292
2293
2294
2295 </tr>
2296
2297
2298
2299
2300 <tr>
2301
2302
2303
2304
2305 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="conserve_volume_flow"></a>conserve_volume_flow</span></td>
2306
2307
2308
2309
2310
2311      <td style="vertical-align: top;">L</td>
2312
2313
2314
2315
2316 <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
2317
2318
2319
2320
2321 <td>Conservation
2322of volume flow in x- and y-direction.<br>
2323
2324
2325
2326
2327 <br>
2328
2329
2330
2331
2332 <span style="font-weight: bold;">conserve_volume_flow</span>
2333= <span style="font-style: italic;">.TRUE.</span>
2334guarantees that the volume flow through the xz- or yz-cross-section of
2335the total model domain remains constant (equal to the initial value at
2336t=0) throughout the run.<br>
2337
2338
2339
2340
2341
2342      </td>
2343
2344
2345
2346
2347 </tr>
2348
2349
2350
2351
2352 <tr>
2353
2354
2355
2356
2357 <td style="vertical-align: top;"> 
2358     
2359     
2360     
2361     
2362      <p><a name="cut_spline_overshoot"></a><b>cut_spline_overshoot</b></p>
2363
2364
2365
2366
2367
2368      </td>
2369
2370
2371
2372
2373 <td style="vertical-align: top;">L</td>
2374
2375
2376
2377
2378
2379      <td style="vertical-align: top;"><span style="font-style: italic;">.T.</span></td>
2380
2381
2382
2383
2384 <td style="vertical-align: top;"> 
2385     
2386     
2387     
2388     
2389      <p>Cuts off of
2390so-called overshoots, which can occur with the
2391upstream-spline scheme.&nbsp; </p>
2392
2393
2394
2395
2396 
2397     
2398     
2399     
2400     
2401      <p><font color="#000000">The cubic splines tend to overshoot in
2402case of discontinuous changes of variables between neighbouring grid
2403points.</font><font color="#ff0000"> </font><font color="#000000">This
2404may lead to errors in calculating the advection tendency.</font>
2405Choice
2406of <b>cut_spline_overshoot</b> = <i>.TRUE.</i>
2407(switched on by
2408default)
2409allows variable values not to exceed an interval defined by the
2410respective adjacent grid points. This interval can be adjusted
2411seperately for every prognostic variable (see initialization parameters
2412      <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>,
2413etc.). This might be necessary in case that the
2414default interval has a non-tolerable effect on the model
2415results.&nbsp; </p>
2416
2417
2418
2419
2420 
2421     
2422     
2423     
2424     
2425      <p>Overshoots may also be removed
2426using the parameters <a href="#ups_limit_e">ups_limit_e</a>,
2427      <a href="#ups_limit_pt">ups_limit_pt</a>,
2428etc. as well as by applying a long-filter (see <a href="#long_filter_factor">long_filter_factor</a>).</p>
2429
2430
2431
2432
2433
2434      </td>
2435
2436
2437
2438
2439 </tr>
2440
2441
2442
2443
2444 <tr>
2445
2446
2447
2448
2449 <td style="vertical-align: top;"> 
2450     
2451     
2452     
2453     
2454      <p><a name="damp_level_1d"></a><b>damp_level_1d</b></p>
2455
2456
2457
2458
2459
2460      </td>
2461
2462
2463
2464
2465 <td style="vertical-align: top;">R</td>
2466
2467
2468
2469
2470
2471      <td style="vertical-align: top;"><span style="font-style: italic;">zu(nz+1)</span></td>
2472
2473
2474
2475
2476
2477      <td style="vertical-align: top;"> 
2478     
2479     
2480     
2481     
2482      <p>Height where
2483the damping layer begins in the 1d-model
2484(in m).&nbsp; </p>
2485
2486
2487
2488
2489 
2490     
2491     
2492     
2493     
2494      <p>This parameter is used to
2495switch on a damping layer for the
24961d-model, which is generally needed for the damping of inertia
2497oscillations. Damping is done by gradually increasing the value
2498of the eddy diffusivities about 10% per vertical grid level
2499(starting with the value at the height given by <b>damp_level_1d</b>,
2500or possibly from the next grid pint above), i.e. K<sub>m</sub>(k+1)
2501=
25021.1 * K<sub>m</sub>(k).
2503The values of K<sub>m</sub> are limited to 10 m**2/s at
2504maximum.&nbsp; <br>
2505
2506
2507
2508
2509
2510This parameter only comes into effect if the 1d-model is switched on
2511for
2512the initialization of the 3d-model using <a href="#initializing_actions">initializing_actions</a>
2513= <span style="font-style: italic;">'set_1d-model_profiles'</span>.
2514      <br>
2515
2516
2517
2518
2519 </p>
2520
2521
2522
2523
2524 </td>
2525
2526
2527
2528
2529 </tr>
2530
2531
2532
2533
2534 <tr>
2535
2536
2537
2538
2539 <td style="vertical-align: top;"><a name="dissipation_1d"></a><span style="font-weight: bold;">dissipation_1d</span><br>
2540
2541
2542
2543
2544
2545      </td>
2546
2547
2548
2549
2550 <td style="vertical-align: top;">C*20<br>
2551
2552
2553
2554
2555
2556      </td>
2557
2558
2559
2560
2561 <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
2562
2563
2564
2565
2566 <span style="font-style: italic;">model'</span><br>
2567
2568
2569
2570
2571 </td>
2572
2573
2574
2575
2576
2577      <td style="vertical-align: top;">Calculation method for
2578the energy dissipation term in the TKE equation of the 1d-model.<br>
2579
2580
2581
2582
2583
2584      <br>
2585
2586
2587
2588
2589
2590By default the dissipation is calculated as in the 3d-model using diss
2591= (0.19 + 0.74 * l / l_grid) * e**1.5 / l.<br>
2592
2593
2594
2595
2596 <br>
2597
2598
2599
2600
2601
2602Setting <span style="font-weight: bold;">dissipation_1d</span>
2603= <span style="font-style: italic;">'detering'</span>
2604forces the dissipation to be calculated as diss = 0.064 * e**1.5 / l.<br>
2605
2606
2607
2608
2609
2610      </td>
2611
2612
2613
2614
2615 </tr>
2616
2617
2618
2619
2620
2621    <tr>
2622
2623
2624
2625
2626 <td style="vertical-align: top;"> 
2627     
2628     
2629     
2630     
2631      <p><a name="dt"></a><b>dt</b></p>
2632
2633
2634
2635
2636 </td>
2637
2638
2639
2640
2641
2642      <td style="vertical-align: top;">R</td>
2643
2644
2645
2646
2647 <td style="vertical-align: top;"><span style="font-style: italic;">variable</span></td>
2648
2649
2650
2651
2652
2653      <td style="vertical-align: top;"> 
2654     
2655     
2656     
2657     
2658      <p>Time step for
2659the 3d-model (in s).&nbsp; </p>
2660
2661
2662
2663
2664 
2665     
2666     
2667     
2668     
2669      <p>By default, (i.e.
2670if a Runge-Kutta scheme is used, see <a href="#timestep_scheme">timestep_scheme</a>)
2671the value of the time step is calculating after each time step
2672(following the time step criteria) and
2673used for the next step.</p>
2674
2675
2676
2677
2678 
2679     
2680     
2681     
2682     
2683      <p>If the user assigns <b>dt</b>
2684a value, then the time step is
2685fixed to this value throughout the whole run (whether it fulfills the
2686time step
2687criteria or not). However, changes are allowed for restart runs,
2688because <b>dt</b> can also be used as a <a href="chapter_4.2.html#dt_laufparameter">run
2689parameter</a>.&nbsp; </p>
2690
2691
2692
2693
2694 
2695     
2696     
2697     
2698     
2699      <p>In case that the
2700calculated time step meets the condition<br>
2701
2702
2703
2704
2705 </p>
2706
2707
2708
2709
2710 
2711     
2712     
2713     
2714     
2715      <ul>
2716
2717
2718
2719
2720
2721       
2722       
2723       
2724       
2725        <p><b>dt</b> &lt; 0.00001 * <a href="chapter_4.2.html#dt_max">dt_max</a> (with dt_max
2726= 20.0)</p>
2727
2728
2729
2730
2731 
2732     
2733     
2734     
2735     
2736      </ul>
2737
2738
2739
2740
2741 
2742     
2743     
2744     
2745     
2746      <p>the simulation will be
2747aborted. Such situations usually arise
2748in case of any numerical problem / instability which causes a
2749non-realistic increase of the wind speed.&nbsp; </p>
2750
2751
2752
2753
2754 
2755     
2756     
2757     
2758     
2759      <p>A
2760small time step due to a large mean horizontal windspeed
2761speed may be enlarged by using a coordinate transformation (see <a href="#galilei_transformation">galilei_transformation</a>),
2762in order to spare CPU time.<br>
2763
2764
2765
2766
2767 </p>
2768
2769
2770
2771
2772 
2773     
2774     
2775     
2776     
2777      <p>If the
2778leapfrog timestep scheme is used (see <a href="#timestep_scheme">timestep_scheme</a>)
2779a temporary time step value dt_new is calculated first, with dt_new = <a href="chapter_4.2.html#fcl_factor">cfl_factor</a>
2780* dt_crit where dt_crit is the maximum timestep allowed by the CFL and
2781diffusion condition. Next it is examined whether dt_new exceeds or
2782falls below the
2783value of the previous timestep by at
2784least +5 % / -2%. If it is smaller, <span style="font-weight: bold;">dt</span>
2785= dt_new is immediately used for the next timestep. If it is larger,
2786then <span style="font-weight: bold;">dt </span>=
27871.02 * dt_prev
2788(previous timestep) is used as the new timestep, however the time
2789step is only increased if the last change of the time step is dated
2790back at
2791least 30 iterations. If dt_new is located in the interval mentioned
2792above, then dt
2793does not change at all. By doing so, permanent time step changes as
2794well as large
2795sudden changes (increases) in the time step are avoided.</p>
2796
2797
2798
2799
2800 </td>
2801
2802
2803
2804
2805
2806    </tr>
2807
2808
2809
2810
2811 <tr>
2812
2813
2814
2815
2816 <td style="vertical-align: top;">
2817     
2818     
2819     
2820     
2821      <p><a name="dt_pr_1d"></a><b>dt_pr_1d</b></p>
2822
2823
2824
2825
2826
2827      </td>
2828
2829
2830
2831
2832 <td style="vertical-align: top;">R</td>
2833
2834
2835
2836
2837
2838      <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
2839
2840
2841
2842
2843
2844      <td style="vertical-align: top;"> 
2845     
2846     
2847     
2848     
2849      <p>Temporal
2850interval of vertical profile output of the 1D-model
2851(in s).&nbsp; </p>
2852
2853
2854
2855
2856 
2857     
2858     
2859     
2860     
2861      <p>Data are written in ASCII
2862format to file <a href="chapter_3.4.html#LIST_PROFIL_1D">LIST_PROFIL_1D</a>.
2863This parameter is only in effect if the 1d-model has been switched on
2864for the
2865initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
2866= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
2867
2868
2869
2870
2871
2872      </td>
2873
2874
2875
2876
2877 </tr>
2878
2879
2880
2881
2882 <tr>
2883
2884
2885
2886
2887 <td style="vertical-align: top;"> 
2888     
2889     
2890     
2891     
2892      <p><a name="dt_run_control_1d"></a><b>dt_run_control_1d</b></p>
2893
2894
2895
2896
2897
2898      </td>
2899
2900
2901
2902
2903 <td style="vertical-align: top;">R</td>
2904
2905
2906
2907
2908
2909      <td style="vertical-align: top;"><span style="font-style: italic;">60.0</span></td>
2910
2911
2912
2913
2914 <td style="vertical-align: top;"> 
2915     
2916     
2917     
2918     
2919      <p>Temporal interval of
2920runtime control output of the 1d-model
2921(in s).&nbsp; </p>
2922
2923
2924
2925
2926 
2927     
2928     
2929     
2930     
2931      <p>Data are written in ASCII
2932format to file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.
2933This parameter is only in effect if the 1d-model is switched on for the
2934initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
2935= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
2936
2937
2938
2939
2940
2941      </td>
2942
2943
2944
2945
2946 </tr>
2947
2948
2949
2950
2951 <tr>
2952
2953
2954
2955
2956 <td style="vertical-align: top;"> 
2957     
2958     
2959     
2960     
2961      <p><a name="dx"></a><b>dx</b></p>
2962
2963
2964
2965
2966
2967      </td>
2968
2969
2970
2971
2972 <td style="vertical-align: top;">R</td>
2973
2974
2975
2976
2977
2978      <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
2979
2980
2981
2982
2983 <td style="vertical-align: top;"> 
2984     
2985     
2986     
2987     
2988      <p>Horizontal grid
2989spacing along the x-direction (in m).&nbsp; </p>
2990
2991
2992
2993
2994 
2995     
2996     
2997     
2998     
2999      <p>Along
3000x-direction only a constant grid spacing is allowed.</p>
3001
3002
3003
3004
3005     
3006     
3007     
3008     
3009      <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>
3010and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
3011
3012
3013
3014
3015 </td>
3016
3017
3018
3019
3020
3021    </tr>
3022
3023
3024
3025
3026 <tr>
3027
3028
3029
3030
3031 <td style="vertical-align: top;">
3032     
3033     
3034     
3035     
3036      <p><a name="dy"></a><b>dy</b></p>
3037
3038
3039
3040
3041
3042      </td>
3043
3044
3045
3046
3047 <td style="vertical-align: top;">R</td>
3048
3049
3050
3051
3052
3053      <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
3054
3055
3056
3057
3058 <td style="vertical-align: top;"> 
3059     
3060     
3061     
3062     
3063      <p>Horizontal grid
3064spacing along the y-direction (in m).&nbsp; </p>
3065
3066
3067
3068
3069 
3070     
3071     
3072     
3073     
3074      <p>Along y-direction only a constant grid spacing is allowed.</p>
3075
3076
3077
3078
3079     
3080     
3081     
3082     
3083      <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>
3084and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
3085
3086
3087
3088
3089 </td>
3090
3091
3092
3093
3094
3095    </tr>
3096
3097
3098
3099
3100 <tr>
3101
3102
3103
3104
3105 <td style="vertical-align: top;">
3106     
3107     
3108     
3109     
3110      <p><a name="dz"></a><b>dz</b></p>
3111
3112
3113
3114
3115
3116      </td>
3117
3118
3119
3120
3121 <td style="vertical-align: top;">R</td>
3122
3123
3124
3125
3126
3127      <td style="vertical-align: top;"><br>
3128
3129
3130
3131
3132 </td>
3133
3134
3135
3136
3137 <td style="vertical-align: top;"> 
3138     
3139     
3140     
3141     
3142      <p>Vertical grid
3143spacing (in m).&nbsp; </p>
3144
3145
3146
3147
3148 
3149     
3150     
3151     
3152     
3153      <p>This parameter must be
3154assigned by the user, because no
3155default value is given.<br>
3156
3157
3158
3159
3160 </p>
3161
3162
3163
3164
3165 
3166     
3167     
3168     
3169     
3170      <p>By default, the
3171model uses constant grid spacing along z-direction, but it can be
3172stretched using the parameters <a href="#dz_stretch_level">dz_stretch_level</a>
3173and <a href="#dz_stretch_factor">dz_stretch_factor</a>.
3174In case of stretching, a maximum allowed grid spacing can be given by <a href="#dz_max">dz_max</a>.<br>
3175
3176
3177
3178
3179 </p>
3180
3181
3182
3183
3184 
3185     
3186     
3187     
3188     
3189      <p>Assuming
3190a constant <span style="font-weight: bold;">dz</span>,
3191the scalar levels (zu) are calculated directly by:&nbsp; </p>
3192
3193
3194
3195
3196
3197     
3198     
3199     
3200     
3201      <ul>
3202
3203
3204
3205
3206 
3207       
3208       
3209       
3210       
3211        <p>zu(0) = - dz * 0.5&nbsp; <br>
3212
3213
3214
3215
3216
3217zu(1) = dz * 0.5</p>
3218
3219
3220
3221
3222 
3223     
3224     
3225     
3226     
3227      </ul>
3228
3229
3230
3231
3232 
3233     
3234     
3235     
3236     
3237      <p>The w-levels lie
3238half between them:&nbsp; </p>
3239
3240
3241
3242
3243 
3244     
3245     
3246     
3247     
3248      <ul>
3249
3250
3251
3252
3253 
3254       
3255       
3256       
3257       
3258        <p>zw(k) =
3259( zu(k) + zu(k+1) ) * 0.5</p>
3260
3261
3262
3263
3264 
3265     
3266     
3267     
3268     
3269      </ul>
3270
3271
3272
3273
3274 </td>
3275
3276
3277
3278
3279 </tr>
3280
3281
3282
3283
3284
3285    <tr>
3286
3287
3288
3289
3290      <td style="vertical-align: top;"><a name="dz_max"></a><span style="font-weight: bold;">dz_max</span></td>
3291
3292
3293
3294
3295      <td style="vertical-align: top;">R</td>
3296
3297
3298
3299
3300      <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
3301
3302
3303
3304
3305      <td style="vertical-align: top;">Allowed maximum vertical grid
3306spacing (in m).<br>
3307
3308
3309
3310
3311      <br>
3312
3313
3314
3315
3316If the vertical grid is stretched
3317(see <a href="#dz_stretch_factor">dz_stretch_factor</a>
3318and <a href="#dz_stretch_level">dz_stretch_level</a>),
3319      <span style="font-weight: bold;">dz_max</span> can
3320be used to limit the vertical grid spacing.</td>
3321
3322
3323
3324
3325    </tr>
3326
3327
3328
3329
3330    <tr>
3331
3332
3333
3334
3335
3336      <td style="vertical-align: top;"> 
3337     
3338     
3339     
3340     
3341      <p><a name="dz_stretch_factor"></a><b>dz_stretch_factor</b></p>
3342
3343
3344
3345
3346
3347      </td>
3348
3349
3350
3351
3352 <td style="vertical-align: top;">R</td>
3353
3354
3355
3356
3357
3358      <td style="vertical-align: top;"><span style="font-style: italic;">1.08</span></td>
3359
3360
3361
3362
3363 <td style="vertical-align: top;"> 
3364     
3365     
3366     
3367     
3368      <p>Stretch factor for a
3369vertically stretched grid (see <a href="#dz_stretch_level">dz_stretch_level</a>).&nbsp;
3370      </p>
3371
3372
3373
3374
3375 
3376     
3377     
3378     
3379     
3380      <p>The stretch factor should not exceed a value of
3381approx. 1.10 -
33821.12, otherwise the discretization errors due to the stretched grid not
3383negligible any more. (refer Kalnay de Rivas)</p>
3384
3385
3386
3387
3388 </td>
3389
3390
3391
3392
3393 </tr>
3394
3395
3396
3397
3398
3399    <tr>
3400
3401
3402
3403
3404 <td style="vertical-align: top;"> 
3405     
3406     
3407     
3408     
3409      <p><a name="dz_stretch_level"></a><b>dz_stretch_level</b></p>
3410
3411
3412
3413
3414
3415      </td>
3416
3417
3418
3419
3420 <td style="vertical-align: top;">R</td>
3421
3422
3423
3424
3425
3426      <td style="vertical-align: top;"><span style="font-style: italic;">100000.0</span><br>
3427
3428
3429
3430
3431 </td>
3432
3433
3434
3435
3436
3437      <td style="vertical-align: top;"> 
3438     
3439     
3440     
3441     
3442      <p>Height level
3443above/below which the grid is to be stretched
3444vertically (in m).&nbsp; </p>
3445
3446
3447
3448
3449 
3450     
3451     
3452     
3453     
3454      <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
3455vertically. The vertical grid
3456spacings <a href="#dz">dz</a>
3457above this level are calculated as&nbsp; </p>
3458
3459
3460
3461
3462 
3463     
3464     
3465     
3466     
3467      <ul>
3468
3469
3470
3471
3472 
3473       
3474       
3475       
3476       
3477        <p><b>dz</b>(k+1)
3478= <b>dz</b>(k) * <a href="#dz_stretch_factor">dz_stretch_factor</a></p>
3479
3480
3481
3482
3483
3484     
3485     
3486     
3487     
3488      </ul>
3489
3490
3491
3492
3493 
3494     
3495     
3496     
3497     
3498      <p>and used as spacings for the scalar levels (zu).
3499The
3500w-levels are then defined as:&nbsp; </p>
3501
3502
3503
3504
3505 
3506     
3507     
3508     
3509     
3510      <ul>
3511
3512
3513
3514
3515 
3516       
3517       
3518       
3519       
3520        <p>zw(k)
3521= ( zu(k) + zu(k+1) ) * 0.5.
3522
3523 
3524     
3525      </p>
3526
3527
3528     
3529     
3530      </ul>
3531
3532
3533     
3534     
3535      <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
3536vertically. The vertical grid
3537spacings <a href="chapter_4.1.html#dz">dz</a> below this level are calculated correspondingly as
3538
3539 
3540     
3541      </p>
3542
3543
3544     
3545     
3546      <ul>
3547
3548
3549       
3550       
3551        <p><b>dz</b>(k-1)
3552= <b>dz</b>(k) * <a href="chapter_4.1.html#dz_stretch_factor">dz_stretch_factor</a>.</p>
3553
3554
3555     
3556     
3557      </ul>
3558
3559
3560
3561
3562 </td>
3563
3564
3565
3566
3567 </tr>
3568
3569
3570
3571
3572
3573    <tr>
3574
3575
3576
3577      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_init"></a>e_init</span></td>
3578
3579
3580
3581      <td style="vertical-align: top;">R</td>
3582
3583
3584
3585      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
3586
3587
3588
3589      <td>Initial subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
3590
3591
3592
3593
3594
3595      <br>
3596
3597
3598
3599
3600This
3601option 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>
3602
3603
3604
3605    </tr>
3606
3607
3608
3609    <tr>
3610
3611
3612
3613
3614 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_min"></a>e_min</span></td>
3615
3616
3617
3618
3619
3620      <td style="vertical-align: top;">R</td>
3621
3622
3623
3624
3625 <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
3626
3627
3628
3629
3630 <td>Minimum
3631subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
3632
3633
3634
3635
3636
3637      <br>
3638
3639
3640
3641
3642This
3643option&nbsp;adds artificial viscosity to the flow by ensuring that
3644the
3645subgrid-scale TKE does not fall below the minimum threshold <span style="font-weight: bold;">e_min</span>.</td>
3646
3647
3648
3649
3650 </tr>
3651
3652
3653
3654
3655
3656    <tr>
3657
3658
3659
3660
3661 <td style="vertical-align: top;"> 
3662     
3663     
3664     
3665     
3666      <p><a name="end_time_1d"></a><b>end_time_1d</b></p>
3667
3668
3669
3670
3671
3672      </td>
3673
3674
3675
3676
3677 <td style="vertical-align: top;">R</td>
3678
3679
3680
3681
3682
3683      <td style="vertical-align: top;"><span style="font-style: italic;">864000.0</span><br>
3684
3685
3686
3687
3688 </td>
3689
3690
3691
3692
3693
3694      <td style="vertical-align: top;"> 
3695     
3696     
3697     
3698     
3699      <p>Time to be
3700simulated for the 1d-model (in s).&nbsp; </p>
3701
3702
3703
3704
3705 
3706     
3707     
3708     
3709     
3710      <p>The
3711default value corresponds to a simulated time of 10 days.
3712Usually, after such a period the inertia oscillations have completely
3713decayed and the solution of the 1d-model can be regarded as stationary
3714(see <a href="#damp_level_1d">damp_level_1d</a>).
3715This parameter is only in effect if the 1d-model is switched on for the
3716initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
3717= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
3718
3719
3720
3721
3722
3723      </td>
3724
3725
3726
3727
3728 </tr>
3729
3730
3731
3732
3733 <tr>
3734
3735
3736
3737
3738 <td style="vertical-align: top;"> 
3739     
3740     
3741     
3742     
3743      <p><a name="fft_method"></a><b>fft_method</b></p>
3744
3745
3746
3747
3748
3749      </td>
3750
3751
3752
3753
3754 <td style="vertical-align: top;">C * 20</td>
3755
3756
3757
3758
3759
3760      <td style="vertical-align: top;"><span style="font-style: italic;">'system-</span><br style="font-style: italic;">
3761
3762
3763
3764
3765 <span style="font-style: italic;">specific'</span></td>
3766
3767
3768
3769
3770
3771      <td style="vertical-align: top;"> 
3772     
3773     
3774     
3775     
3776      <p>FFT-method to
3777be used.<br>
3778
3779
3780
3781
3782 </p>
3783
3784
3785
3786
3787 
3788     
3789     
3790     
3791     
3792      <p><br>
3793
3794
3795
3796
3797
3798The fast fourier transformation (FFT) is used for solving the
3799perturbation pressure equation with a direct method (see <a href="chapter_4.2.html#psolver">psolver</a>)
3800and for calculating power spectra (see optional software packages,
3801section <a href="chapter_4.2.html#spectra_package">4.2</a>).</p>
3802
3803
3804
3805
3806
3807     
3808     
3809     
3810     
3811      <p><br>
3812
3813
3814
3815
3816
3817By default, system-specific, optimized routines from external
3818vendor libraries are used. However, these are available only on certain
3819computers and there are more or less severe restrictions concerning the
3820number of gridpoints to be used with them.<br>
3821
3822
3823
3824
3825 </p>
3826
3827
3828
3829
3830 
3831     
3832     
3833     
3834     
3835      <p>There
3836are two other PALM internal methods available on every
3837machine (their respective source code is part of the PALM source code):</p>
3838
3839
3840
3841
3842
3843     
3844     
3845     
3846     
3847      <p>1.: The <span style="font-weight: bold;">Temperton</span>-method
3848from Clive Temperton (ECWMF) which is computationally very fast and
3849switched on with <b>fft_method</b> = <span style="font-style: italic;">'temperton-algorithm'</span>.
3850The number of horizontal gridpoints (nx+1, ny+1) to be used with this
3851method must be composed of prime factors 2, 3 and 5.<br>
3852
3853
3854
3855
3856 </p>
3857
3858
3859
3860
3861
38622.: The <span style="font-weight: bold;">Singleton</span>-method
3863which is very slow but has no restrictions concerning the number of
3864gridpoints to be used with, switched on with <b>fft_method</b>
3865= <span style="font-style: italic;">'singleton-algorithm'</span>.
3866      </td>
3867
3868
3869
3870
3871 </tr>
3872
3873
3874
3875
3876 <tr>
3877
3878
3879
3880
3881 <td style="vertical-align: top;"> 
3882     
3883     
3884     
3885     
3886      <p><a name="galilei_transformation"></a><b>galilei_transformation</b></p>
3887
3888
3889
3890
3891
3892      </td>
3893
3894
3895
3896
3897 <td style="vertical-align: top;">L</td>
3898
3899
3900
3901
3902
3903      <td style="vertical-align: top;"><i>.F.</i></td>
3904
3905
3906
3907
3908
3909      <td style="vertical-align: top;">Application of a
3910Galilei-transformation to the
3911coordinate
3912system of the model.<br>
3913
3914
3915
3916
3917     
3918     
3919     
3920     
3921      <p>With <b>galilei_transformation</b>
3922= <i>.T.,</i> a so-called
3923Galilei-transformation is switched on which ensures that the coordinate
3924system of the model is moved along with the geostrophical wind.
3925Alternatively, the model domain can be moved along with the averaged
3926horizontal wind (see <a href="#use_ug_for_galilei_tr">use_ug_for_galilei_tr</a>,
3927this can and will naturally change in time). With this method,
3928numerical inaccuracies of the Piascek - Williams - scheme (concerns in
3929particular the momentum advection) are minimized. Beyond that, in the
3930majority of cases the lower relative velocities in the moved system
3931permit a larger time step (<a href="#dt">dt</a>).
3932Switching the transformation on is only worthwhile if the geostrophical
3933wind (ug, vg)
3934and the averaged horizontal wind clearly deviate from the value 0. In
3935each case, the distance the coordinate system has been moved is written
3936to the file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.&nbsp;
3937      </p>
3938
3939
3940
3941
3942 
3943     
3944     
3945     
3946     
3947      <p>Non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
3948and <a href="#bc_ns">bc_ns</a>), the specification
3949of a gestrophic
3950wind that is not constant with height
3951as well as e.g. stationary inhomogeneities at the bottom boundary do
3952not allow the use of this transformation.</p>
3953
3954
3955
3956
3957 </td>
3958
3959
3960
3961
3962 </tr>
3963
3964
3965
3966
3967
3968    <tr>
3969
3970
3971
3972
3973 <td style="vertical-align: top;"> 
3974     
3975     
3976     
3977     
3978      <p><a name="grid_matching"></a><b>grid_matching</b></p>
3979
3980
3981
3982
3983
3984      </td>
3985
3986
3987
3988
3989 <td style="vertical-align: top;">C * 6</td>
3990
3991
3992
3993
3994
3995      <td style="vertical-align: top;"><span style="font-style: italic;">'match'</span></td>
3996
3997
3998
3999
4000 <td style="vertical-align: top;">Variable to adjust the
4001subdomain
4002sizes in parallel runs.<br>
4003
4004
4005
4006
4007 <br>
4008
4009
4010
4011
4012
4013For <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>,
4014the subdomains are forced to have an identical
4015size on all processors. In this case the processor numbers in the
4016respective directions of the virtual processor net must fulfill certain
4017divisor conditions concerning the grid point numbers in the three
4018directions (see <a href="#nx">nx</a>, <a href="#ny">ny</a>
4019and <a href="#nz">nz</a>).
4020Advantage of this method is that all PEs bear the same computational
4021load.<br>
4022
4023
4024
4025
4026 <br>
4027
4028
4029
4030
4031
4032There is no such restriction by default, because then smaller
4033subdomains are allowed on those processors which
4034form the right and/or north boundary of the virtual processor grid. On
4035all other processors the subdomains are of same size. Whether smaller
4036subdomains are actually used, depends on the number of processors and
4037the grid point numbers used. Information about the respective settings
4038are 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>
4039
4040
4041
4042
4043
4044      <br>
4045
4046
4047
4048
4049
4050When 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>)
4051only <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>
4052is allowed.<br>
4053
4054
4055
4056
4057 <br>
4058
4059
4060
4061
4062 <b>Note:</b><br>
4063
4064
4065
4066
4067
4068In some cases for small processor numbers there may be a very bad load
4069balancing among the
4070processors which may reduce the performance of the code.</td>
4071
4072
4073
4074
4075 </tr>
4076
4077
4078
4079
4080
4081    <tr>
4082
4083
4084
4085
4086 <td style="vertical-align: top;"><a name="inflow_disturbance_begin"></a><b>inflow_disturbance_<br>
4087
4088
4089
4090
4091
4092begin</b></td>
4093
4094
4095
4096
4097 <td style="vertical-align: top;">I</td>
4098
4099
4100
4101
4102
4103      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(10,</span><br style="font-style: italic;">
4104
4105
4106
4107
4108 <span style="font-style: italic;">nx/2 or ny/2)</span></td>
4109
4110
4111
4112
4113
4114      <td style="vertical-align: top;">Lower
4115limit of the horizontal range for which random perturbations are to be
4116imposed on the horizontal velocity field (gridpoints).<br>
4117
4118
4119
4120
4121 <br>
4122
4123
4124
4125
4126
4127If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
4128or <a href="#bc_ns">bc_ns</a>),
4129this parameter gives the gridpoint number (counted horizontally from
4130the inflow)&nbsp; from which on perturbations are imposed on the
4131horizontal velocity field. Perturbations must be switched on with
4132parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
4133
4134
4135
4136
4137
4138    </tr>
4139
4140
4141
4142
4143 <tr>
4144
4145
4146
4147
4148 <td style="vertical-align: top;"><a name="inflow_disturbance_end"></a><b>inflow_disturbance_<br>
4149
4150
4151
4152
4153
4154end</b></td>
4155
4156
4157
4158
4159 <td style="vertical-align: top;">I</td>
4160
4161
4162
4163
4164
4165      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(100,</span><br style="font-style: italic;">
4166
4167
4168
4169
4170 <span style="font-style: italic;">3/4*nx or</span><br style="font-style: italic;">
4171
4172
4173
4174
4175 <span style="font-style: italic;">3/4*ny)</span></td>
4176
4177
4178
4179
4180 <td style="vertical-align: top;">Upper
4181limit of the horizontal range for which random perturbations are
4182to be imposed on the horizontal velocity field (gridpoints).<br>
4183
4184
4185
4186
4187 <br>
4188
4189
4190
4191
4192
4193If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
4194or <a href="#bc_ns">bc_ns</a>),
4195this parameter gives the gridpoint number (counted horizontally from
4196the inflow)&nbsp; unto which perturbations are imposed on the
4197horizontal
4198velocity field. Perturbations must be switched on with parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
4199
4200
4201
4202
4203
4204    </tr>
4205
4206
4207
4208
4209 <tr>
4210
4211
4212
4213
4214 <td style="vertical-align: top;">
4215     
4216     
4217     
4218     
4219      <p><a name="initializing_actions"></a><b>initializing_actions</b></p>
4220
4221
4222
4223
4224
4225      </td>
4226
4227
4228
4229
4230 <td style="vertical-align: top;">C * 100</td>
4231
4232
4233
4234
4235
4236      <td style="vertical-align: top;"><br>
4237
4238
4239
4240
4241 </td>
4242
4243
4244
4245
4246 <td style="vertical-align: top;"> 
4247     
4248     
4249     
4250     
4251      <p style="font-style: normal;">Initialization actions
4252to be carried out.&nbsp; </p>
4253
4254
4255
4256
4257 
4258     
4259     
4260     
4261     
4262      <p style="font-style: normal;">This parameter does not have a
4263default value and therefore must be assigned with each model run. For
4264restart runs <b>initializing_actions</b> = <span style="font-style: italic;">'read_restart_data'</span>
4265must be set. For the initial run of a job chain the following values
4266are allowed:&nbsp; </p>
4267
4268
4269
4270
4271 
4272     
4273     
4274     
4275     
4276      <p style="font-style: normal;"><span style="font-style: italic;">'set_constant_profiles'</span>
4277      </p>
4278
4279
4280
4281
4282 
4283     
4284     
4285     
4286     
4287      <ul>
4288
4289
4290
4291
4292 
4293       
4294       
4295       
4296       
4297        <p>A horizontal wind profile consisting
4298of linear sections (see <a href="#ug_surface">ug_surface</a>,
4299        <a href="#ug_vertical_gradient">ug_vertical_gradient</a>,
4300        <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>
4301and <a href="#vg_surface">vg_surface</a>, <a href="#vg_vertical_gradient">vg_vertical_gradient</a>,
4302        <a href="#vg_vertical_gradient_level">vg_vertical_gradient_level</a>,
4303respectively) as well as a vertical temperature (humidity) profile
4304consisting of
4305linear sections (see <a href="#pt_surface">pt_surface</a>,
4306        <a href="#pt_vertical_gradient">pt_vertical_gradient</a>,
4307        <a href="#q_surface">q_surface</a>
4308and <a href="#q_vertical_gradient">q_vertical_gradient</a>)
4309are assumed as initial profiles. The subgrid-scale TKE is set to 0 but K<sub>m</sub>
4310and K<sub>h</sub> are set to very small values because
4311otherwise no TKE
4312would be generated.</p>
4313
4314
4315
4316
4317 
4318     
4319     
4320     
4321     
4322      </ul>
4323
4324
4325
4326
4327 
4328     
4329     
4330     
4331     
4332      <p style="font-style: italic;">'set_1d-model_profiles' </p>
4333
4334
4335
4336
4337
4338     
4339     
4340     
4341     
4342      <ul>
4343
4344
4345
4346
4347 
4348       
4349       
4350       
4351       
4352        <p>The arrays of the 3d-model are initialized with
4353the
4354(stationary) solution of the 1d-model. These are the variables e, kh,
4355km, u, v and with Prandtl layer switched on rif, us, usws, vsws. The
4356temperature (humidity) profile consisting of linear sections is set as
4357for 'set_constant_profiles' and assumed as constant in time within the
43581d-model. For steering of the 1d-model a set of parameters with suffix
4359"_1d" (e.g. <a href="#end_time_1d">end_time_1d</a>,
4360        <a href="#damp_level_1d">damp_level_1d</a>)
4361is available.</p>
4362
4363
4364
4365
4366 
4367     
4368     
4369     
4370     
4371      </ul>
4372
4373
4374
4375
4376 
4377     
4378     
4379     
4380     
4381      <p><span style="font-style: italic;">'by_user'</span></p>
4382
4383
4384
4385
4386     
4387     
4388     
4389     
4390      <p style="margin-left: 40px;">The initialization of the arrays
4391of the 3d-model is under complete control of the user and has to be
4392done in routine <a href="chapter_3.5.1.html#user_init_3d_model">user_init_3d_model</a>
4393of the user-interface.<span style="font-style: italic;"></span></p>
4394
4395
4396
4397
4398     
4399     
4400     
4401     
4402      <p><span style="font-style: italic;">'initialize_vortex'</span>
4403      </p>
4404
4405
4406
4407
4408 
4409     
4410     
4411     
4412     
4413      <div style="margin-left: 40px;">The initial
4414velocity field of the
44153d-model corresponds to a
4416Rankine-vortex with vertical axis. This setting may be used to test
4417advection 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>)
4418are necessary. In order not to distort the vortex, an initial
4419horizontal wind profile constant
4420with height is necessary (to be set by <b>initializing_actions</b>
4421= <span style="font-style: italic;">'set_constant_profiles'</span>)
4422and some other conditions have to be met (neutral stratification,
4423diffusion must be
4424switched off, see <a href="#km_constant">km_constant</a>).
4425The center of the vortex is located at jc = (nx+1)/2. It
4426extends from k = 0 to k = nz+1. Its radius is 8 * <a href="#dx">dx</a>
4427and the exponentially decaying part ranges to 32 * <a href="#dx">dx</a>
4428(see init_rankine.f90). </div>
4429
4430
4431
4432
4433 
4434     
4435     
4436     
4437     
4438      <p><span style="font-style: italic;">'initialize_ptanom'</span>
4439      </p>
4440
4441
4442
4443
4444 
4445     
4446     
4447     
4448     
4449      <ul>
4450
4451
4452
4453
4454 
4455       
4456       
4457       
4458       
4459        <p>A 2d-Gauss-like shape disturbance
4460(x,y) is added to the
4461initial temperature field with radius 10.0 * <a href="#dx">dx</a>
4462and center at jc = (nx+1)/2. This may be used for tests of scalar
4463advection schemes
4464(see <a href="#scalar_advec">scalar_advec</a>).
4465Such tests require a horizontal wind profile constant with hight and
4466diffusion
4467switched off (see <span style="font-style: italic;">'initialize_vortex'</span>).
4468Additionally, the buoyancy term
4469must be switched of in the equation of motion&nbsp; for w (this
4470requires the user to comment out the call of <span style="font-family: monospace;">buoyancy</span> in the
4471source code of <span style="font-family: monospace;">prognostic_equations.f90</span>).</p>
4472
4473
4474
4475
4476
4477     
4478     
4479     
4480     
4481      </ul>
4482
4483
4484
4485
4486 
4487     
4488     
4489     
4490     
4491      <p style="font-style: normal;">Values may be
4492combined, e.g. <b>initializing_actions</b> = <span style="font-style: italic;">'set_constant_profiles
4493initialize_vortex'</span>, but the values of <span style="font-style: italic;">'set_constant_profiles'</span>,
4494      <span style="font-style: italic;">'set_1d-model_profiles'</span>
4495, and <span style="font-style: italic;">'by_user'</span>
4496must not be given at the same time.</p>
4497
4498
4499
4500
4501 
4502     
4503     
4504     
4505     
4506      <p style="font-style: italic;"> </p>
4507
4508
4509
4510
4511 </td>
4512
4513
4514
4515
4516 </tr>
4517
4518
4519
4520
4521
4522    <tr>
4523
4524
4525
4526
4527 <td style="vertical-align: top;"> 
4528     
4529     
4530     
4531     
4532      <p><a name="km_constant"></a><b>km_constant</b></p>
4533
4534
4535
4536
4537
4538      </td>
4539
4540
4541
4542
4543 <td style="vertical-align: top;">R</td>
4544
4545
4546
4547
4548
4549      <td style="vertical-align: top;"><i>variable<br>
4550
4551
4552
4553
4554
4555(computed from TKE)</i></td>
4556
4557
4558
4559
4560 <td style="vertical-align: top;"> 
4561     
4562     
4563     
4564     
4565      <p>Constant eddy
4566diffusivities are used (laminar
4567simulations).&nbsp; </p>
4568
4569
4570
4571
4572 
4573     
4574     
4575     
4576     
4577      <p>If this parameter is
4578specified, both in the 1d and in the
45793d-model constant values for the eddy diffusivities are used in
4580space and time with K<sub>m</sub> = <b>km_constant</b>
4581and K<sub>h</sub> = K<sub>m</sub> / <a href="chapter_4.2.html#prandtl_number">prandtl_number</a>.
4582The prognostic equation for the subgrid-scale TKE is switched off.
4583Constant eddy diffusivities are only allowed with the Prandtl layer (<a href="#prandtl_layer">prandtl_layer</a>)
4584switched off.</p>
4585
4586
4587
4588
4589 </td>
4590
4591
4592
4593
4594 </tr>
4595
4596
4597
4598
4599 <tr>
4600
4601
4602
4603
4604 <td style="vertical-align: top;"> 
4605     
4606     
4607     
4608     
4609      <p><a name="km_damp_max"></a><b>km_damp_max</b></p>
4610
4611
4612
4613
4614
4615      </td>
4616
4617
4618
4619
4620 <td style="vertical-align: top;">R</td>
4621
4622
4623
4624
4625
4626      <td style="vertical-align: top;"><span style="font-style: italic;">0.5*(dx
4627or dy)</span></td>
4628
4629
4630
4631
4632 <td style="vertical-align: top;">Maximum
4633diffusivity used for filtering the velocity field in the vicinity of
4634the outflow (in m<sup>2</sup>/s).<br>
4635
4636
4637
4638
4639 <br>
4640
4641
4642
4643
4644
4645When using non-cyclic lateral boundaries (see <a href="#bc_lr">bc_lr</a>
4646or <a href="#bc_ns">bc_ns</a>),
4647a smoothing has to be applied to the
4648velocity field in the vicinity of the outflow in order to suppress any
4649reflections of outgoing disturbances. Smoothing is done by increasing
4650the eddy diffusivity along the horizontal direction which is
4651perpendicular to the outflow boundary. Only velocity components
4652parallel to the outflow boundary are filtered (e.g. v and w, if the
4653outflow is along x). Damping is applied from the bottom to the top of
4654the domain.<br>
4655
4656
4657
4658
4659 <br>
4660
4661
4662
4663
4664
4665The horizontal range of the smoothing is controlled by <a href="#outflow_damping_width">outflow_damping_width</a>
4666which defines the number of gridpoints (counted from the outflow
4667boundary) from where on the smoothing is applied. Starting from that
4668point, the eddy diffusivity is linearly increased (from zero to its
4669maximum value given by <span style="font-weight: bold;">km_damp_max</span>)
4670until half of the damping range width, from where it remains constant
4671up to the outflow boundary. If at a certain grid point the eddy
4672diffusivity calculated from the flow field is larger than as described
4673above, it is used instead.<br>
4674
4675
4676
4677
4678 <br>
4679
4680
4681
4682
4683
4684The default value of <span style="font-weight: bold;">km_damp_max</span>
4685has been empirically proven to be sufficient.</td>
4686
4687
4688
4689
4690 </tr>
4691
4692
4693
4694
4695 <tr>
4696
4697
4698
4699
4700
4701      <td style="vertical-align: top;"> 
4702     
4703     
4704     
4705     
4706      <p><a name="long_filter_factor"></a><b>long_filter_factor</b></p>
4707
4708
4709
4710
4711
4712      </td>
4713
4714
4715
4716
4717 <td style="vertical-align: top;">R</td>
4718
4719
4720
4721
4722
4723      <td style="vertical-align: top;"><i>0.0</i></td>
4724
4725
4726
4727
4728
4729      <td style="vertical-align: top;"> 
4730     
4731     
4732     
4733     
4734      <p>Filter factor
4735for the so-called Long-filter.<br>
4736
4737
4738
4739
4740 </p>
4741
4742
4743
4744
4745 
4746     
4747     
4748     
4749     
4750      <p><br>
4751
4752
4753
4754
4755
4756This filter very efficiently
4757eliminates 2-delta-waves sometimes cauesed by the upstream-spline
4758scheme (see Mahrer and
4759Pielke, 1978: Mon. Wea. Rev., 106, 818-830). It works in all three
4760directions in space. A value of <b>long_filter_factor</b>
4761= <i>0.01</i>
4762sufficiently removes the small-scale waves without affecting the
4763longer waves.<br>
4764
4765
4766
4767
4768 </p>
4769
4770
4771
4772
4773 
4774     
4775     
4776     
4777     
4778      <p>By default, the filter is
4779switched off (= <i>0.0</i>).
4780It is exclusively applied to the tendencies calculated by the
4781upstream-spline scheme (see <a href="#momentum_advec">momentum_advec</a>
4782and <a href="#scalar_advec">scalar_advec</a>),
4783not to the prognostic variables themselves. At the bottom and top
4784boundary of the model domain the filter effect for vertical
47852-delta-waves is reduced. There, the amplitude of these waves is only
4786reduced by approx. 50%, otherwise by nearly 100%.&nbsp; <br>
4787
4788
4789
4790
4791
4792Filter factors with values &gt; <i>0.01</i> also
4793reduce the amplitudes
4794of waves with wavelengths longer than 2-delta (see the paper by Mahrer
4795and
4796Pielke, quoted above). </p>
4797
4798
4799
4800
4801 </td>
4802
4803
4804
4805
4806 </tr>
4807
4808
4809
4810
4811 <tr>
4812
4813
4814
4815
4816      <td style="vertical-align: top;"><a name="loop_optimization"></a><span style="font-weight: bold;">loop_optimization</span></td>
4817
4818
4819
4820
4821      <td style="vertical-align: top;">C*16</td>
4822
4823
4824
4825
4826      <td style="vertical-align: top;"><span style="font-style: italic;">see right</span></td>
4827
4828
4829
4830
4831      <td>Method used to optimize loops for solving the prognostic equations .<br>
4832
4833
4834
4835
4836      <br>
4837
4838
4839
4840
4841By
4842default, the optimization method depends on the host on which PALM is
4843running. On machines with vector-type CPUs, single 3d-loops are used to
4844calculate each tendency term of each prognostic equation, while on all
4845other machines, all prognostic equations are solved within one big loop
4846over 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>
4847
4848
4849
4850
4851      <br>
4852
4853
4854
4855
4856The 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>
4857
4858
4859
4860
4861    </tr>
4862
4863
4864
4865
4866    <tr>
4867
4868
4869
4870
4871
4872      <td style="vertical-align: top;"><a name="mixing_length_1d"></a><span style="font-weight: bold;">mixing_length_1d</span><br>
4873
4874
4875
4876
4877
4878      </td>
4879
4880
4881
4882
4883 <td style="vertical-align: top;">C*20<br>
4884
4885
4886
4887
4888
4889      </td>
4890
4891
4892
4893
4894 <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
4895
4896
4897
4898
4899 <span style="font-style: italic;">model'</span><br>
4900
4901
4902
4903
4904 </td>
4905
4906
4907
4908
4909
4910      <td style="vertical-align: top;">Mixing length used in the
49111d-model.<br>
4912
4913
4914
4915
4916 <br>
4917
4918
4919
4920
4921
4922By default the mixing length is calculated as in the 3d-model (i.e. it
4923depends on the grid spacing).<br>
4924
4925
4926
4927
4928 <br>
4929
4930
4931
4932
4933
4934By setting <span style="font-weight: bold;">mixing_length_1d</span>
4935= <span style="font-style: italic;">'blackadar'</span>,
4936the so-called Blackadar mixing length is used (l = kappa * z / ( 1 +
4937kappa * z / lambda ) with the limiting value lambda = 2.7E-4 * u_g / f).<br>
4938
4939
4940
4941
4942
4943      </td>
4944
4945
4946
4947
4948 </tr>
4949
4950
4951
4952
4953 <tr>
4954
4955
4956
4957
4958 <td style="vertical-align: top;"> 
4959     
4960     
4961     
4962     
4963      <p><a name="humidity"></a><b>humidity</b></p>
4964
4965
4966
4967
4968
4969      </td>
4970
4971
4972
4973
4974 <td style="vertical-align: top;">L</td>
4975
4976
4977
4978
4979
4980      <td style="vertical-align: top;"><i>.F.</i></td>
4981
4982
4983
4984
4985
4986      <td style="vertical-align: top;"> 
4987     
4988     
4989     
4990     
4991      <p>Parameter to
4992switch on the prognostic equation for specific
4993humidity q.<br>
4994
4995
4996
4997
4998 </p>
4999
5000
5001
5002
5003 
5004     
5005     
5006     
5007     
5008      <p>The initial vertical
5009profile 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>
5010and <a href="chapter_4.1.html#q_vertical_gradient_level">q_vertical_gradient_level</a>.&nbsp;
5011Boundary conditions can be set via <a href="chapter_4.1.html#q_surface_initial_change">q_surface_initial_change</a>
5012and <a href="chapter_4.1.html#surface_waterflux">surface_waterflux</a>.<br>
5013
5014
5015
5016
5017
5018      </p>
5019
5020
5021
5022
5023
5024If the condensation scheme is switched on (<a href="chapter_4.1.html#cloud_physics">cloud_physics</a>
5025= .TRUE.), q becomes the total liquid water content (sum of specific
5026humidity and liquid water content).</td>
5027
5028
5029
5030
5031 </tr>
5032
5033
5034
5035
5036
5037    <tr>
5038
5039
5040
5041
5042 <td style="vertical-align: top;"> 
5043     
5044     
5045     
5046     
5047      <p><a name="momentum_advec"></a><b>momentum_advec</b></p>
5048
5049
5050
5051
5052
5053      </td>
5054
5055
5056
5057
5058 <td style="vertical-align: top;">C * 10</td>
5059
5060
5061
5062
5063
5064      <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
5065
5066
5067
5068
5069
5070      <td style="vertical-align: top;"> 
5071     
5072     
5073     
5074     
5075      <p>Advection
5076scheme to be used for the momentum equations.<br>
5077
5078
5079
5080
5081 <br>
5082
5083
5084
5085
5086
5087The user can choose between the following schemes:<br>
5088
5089
5090
5091
5092
5093&nbsp;<br>
5094
5095
5096
5097
5098 <br>
5099
5100
5101
5102
5103 <span style="font-style: italic;">'pw-scheme'</span><br>
5104
5105
5106
5107
5108
5109      </p>
5110
5111
5112
5113
5114 
5115     
5116     
5117     
5118     
5119      <div style="margin-left: 40px;">The scheme of
5120Piascek and
5121Williams (1970, J. Comp. Phys., 6,
5122392-405) with central differences in the form C3 is used.<br>
5123
5124
5125
5126
5127
5128If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
5129= <span style="font-style: italic;">'leapfrog+euler'</span>
5130the
5131advection scheme is - for the Euler-timestep - automatically switched
5132to an upstream-scheme.<br>
5133
5134
5135
5136
5137 </div>
5138
5139
5140
5141
5142 
5143     
5144     
5145     
5146     
5147      <p> </p>
5148
5149
5150
5151
5152 
5153     
5154     
5155     
5156     
5157      <p><span style="font-style: italic;">'ups-scheme'</span><br>
5158
5159
5160
5161
5162
5163      </p>
5164
5165
5166
5167
5168 
5169     
5170     
5171     
5172     
5173      <div style="margin-left: 40px;">The
5174upstream-spline scheme is
5175used
5176(see Mahrer and Pielke,
51771978: Mon. Wea. Rev., 106, 818-830). In opposite to the
5178Piascek-Williams scheme, this is characterized by much better numerical
5179features (less numerical diffusion, better preservation of flow
5180structures, e.g. vortices), but computationally it is much more
5181expensive. In
5182addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
5183= <span style="font-style: italic;">'</span><i>euler'</i>),
5184i.e. the
5185timestep accuracy is only of first order.
5186For this reason the advection of scalar variables (see <a href="#scalar_advec">scalar_advec</a>)
5187should then also be carried out with the upstream-spline scheme,
5188because otherwise the scalar variables would
5189be subject to large numerical diffusion due to the upstream
5190scheme.&nbsp; </div>
5191
5192
5193
5194
5195 
5196     
5197     
5198     
5199     
5200      <p style="margin-left: 40px;">Since
5201the cubic splines used tend
5202to overshoot under
5203certain circumstances, this effect must be adjusted by suitable
5204filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
5205      <a href="#long_filter_factor">long_filter_factor</a>,
5206      <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>).
5207This is always neccessary for runs with stable stratification,
5208even if this stratification appears only in parts of the model domain.<br>
5209
5210
5211
5212
5213
5214      </p>
5215
5216
5217
5218
5219 
5220     
5221     
5222     
5223     
5224      <div style="margin-left: 40px;">With stable
5225stratification the
5226upstream-spline scheme also
5227produces gravity waves with large amplitude, which must be
5228suitably damped (see <a href="chapter_4.2.html#rayleigh_damping_factor">rayleigh_damping_factor</a>).<br>
5229
5230
5231
5232
5233
5234      <br>
5235
5236
5237
5238
5239 <span style="font-weight: bold;">Important: </span>The&nbsp;
5240upstream-spline scheme is not implemented for humidity and passive
5241scalars (see&nbsp;<a href="#humidity">humidity</a>
5242and <a href="#passive_scalar">passive_scalar</a>)
5243and requires the use of a 2d-domain-decomposition. The last conditions
5244severely restricts code optimization on several machines leading to
5245very long execution times! The scheme is also not allowed for
5246non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
5247and <a href="#bc_ns">bc_ns</a>).</div>
5248
5249
5250
5251
5252 </td>
5253
5254
5255
5256
5257
5258    </tr>
5259
5260
5261
5262
5263 <tr>
5264
5265
5266
5267
5268 <td style="vertical-align: top;"><a name="netcdf_precision"></a><span style="font-weight: bold;">netcdf_precision</span><br>
5269
5270
5271
5272
5273
5274      </td>
5275
5276
5277
5278
5279 <td style="vertical-align: top;">C*20<br>
5280
5281
5282
5283
5284
5285(10)<br>
5286
5287
5288
5289
5290 </td>
5291
5292
5293
5294
5295 <td style="vertical-align: top;"><span style="font-style: italic;">single preci-</span><br style="font-style: italic;">
5296
5297
5298
5299
5300 <span style="font-style: italic;">sion for all</span><br style="font-style: italic;">
5301
5302
5303
5304
5305 <span style="font-style: italic;">output quan-</span><br style="font-style: italic;">
5306
5307
5308
5309
5310 <span style="font-style: italic;">tities</span><br>
5311
5312
5313
5314
5315 </td>
5316
5317
5318
5319
5320
5321      <td style="vertical-align: top;">Defines the accuracy of
5322the NetCDF output.<br>
5323
5324
5325
5326
5327 <br>
5328
5329
5330
5331
5332
5333By default, all NetCDF output data (see <a href="chapter_4.2.html#data_output_format">data_output_format</a>)
5334have single precision&nbsp; (4 byte) accuracy. Double precision (8
5335byte) can be choosen alternatively.<br>
5336
5337
5338
5339
5340
5341Accuracy for the different output data (cross sections, 3d-volume data,
5342spectra, etc.) can be set independently.<br>
5343
5344
5345
5346
5347 <span style="font-style: italic;">'&lt;out&gt;_NF90_REAL4'</span>
5348(single precision) or <span style="font-style: italic;">'&lt;out&gt;_NF90_REAL8'</span>
5349(double precision) are the two principally allowed values for <span style="font-weight: bold;">netcdf_precision</span>,
5350where the string <span style="font-style: italic;">'&lt;out&gt;'
5351      </span>can be chosen out of the following list:<br>
5352
5353
5354
5355
5356 <br>
5357
5358
5359
5360
5361
5362     
5363     
5364     
5365     
5366      <table style="text-align: left; width: 284px; height: 234px;" border="1" cellpadding="2" cellspacing="2">
5367
5368
5369
5370
5371 <tbody>
5372
5373
5374
5375
5376
5377          <tr>
5378
5379
5380
5381
5382 <td style="vertical-align: top;"><span style="font-style: italic;">'xy'</span><br>
5383
5384
5385
5386
5387 </td>
5388
5389
5390
5391
5392
5393            <td style="vertical-align: top;">horizontal cross section<br>
5394
5395
5396
5397
5398
5399            </td>
5400
5401
5402
5403
5404 </tr>
5405
5406
5407
5408
5409 <tr>
5410
5411
5412
5413
5414 <td style="vertical-align: top;"><span style="font-style: italic;">'xz'</span><br>
5415
5416
5417
5418
5419 </td>
5420
5421
5422
5423
5424
5425            <td style="vertical-align: top;">vertical (xz) cross
5426section<br>
5427
5428
5429
5430
5431 </td>
5432
5433
5434
5435
5436 </tr>
5437
5438
5439
5440
5441 <tr>
5442
5443
5444
5445
5446 <td style="vertical-align: top;"><span style="font-style: italic;">'yz'</span><br>
5447
5448
5449
5450
5451 </td>
5452
5453
5454
5455
5456
5457            <td style="vertical-align: top;">vertical (yz) cross
5458section<br>
5459
5460
5461
5462
5463 </td>
5464
5465
5466
5467
5468 </tr>
5469
5470
5471
5472
5473 <tr>
5474
5475
5476
5477
5478 <td style="vertical-align: top;"><span style="font-style: italic;">'2d'</span><br>
5479
5480
5481
5482
5483 </td>
5484
5485
5486
5487
5488
5489            <td style="vertical-align: top;">all cross sections<br>
5490
5491
5492
5493
5494
5495            </td>
5496
5497
5498
5499
5500 </tr>
5501
5502
5503
5504
5505 <tr>
5506
5507
5508
5509
5510 <td style="vertical-align: top;"><span style="font-style: italic;">'3d'</span><br>
5511
5512
5513
5514
5515 </td>
5516
5517
5518
5519
5520
5521            <td style="vertical-align: top;">volume data<br>
5522
5523
5524
5525
5526 </td>
5527
5528
5529
5530
5531
5532          </tr>
5533
5534
5535
5536
5537 <tr>
5538
5539
5540
5541
5542 <td style="vertical-align: top;"><span style="font-style: italic;">'pr'</span><br>
5543
5544
5545
5546
5547 </td>
5548
5549
5550
5551
5552
5553            <td style="vertical-align: top;">vertical profiles<br>
5554
5555
5556
5557
5558
5559            </td>
5560
5561
5562
5563
5564 </tr>
5565
5566
5567
5568
5569 <tr>
5570
5571
5572
5573
5574 <td style="vertical-align: top;"><span style="font-style: italic;">'ts'</span><br>
5575
5576
5577
5578
5579 </td>
5580
5581
5582
5583
5584
5585            <td style="vertical-align: top;">time series, particle
5586time series<br>
5587
5588
5589
5590
5591 </td>
5592
5593
5594
5595
5596 </tr>
5597
5598
5599
5600
5601 <tr>
5602
5603
5604
5605
5606 <td style="vertical-align: top;"><span style="font-style: italic;">'sp'</span><br>
5607
5608
5609
5610
5611 </td>
5612
5613
5614
5615
5616
5617            <td style="vertical-align: top;">spectra<br>
5618
5619
5620
5621
5622 </td>
5623
5624
5625
5626
5627
5628          </tr>
5629
5630
5631
5632
5633 <tr>
5634
5635
5636
5637
5638 <td style="vertical-align: top;"><span style="font-style: italic;">'prt'</span><br>
5639
5640
5641
5642
5643 </td>
5644
5645
5646
5647
5648
5649            <td style="vertical-align: top;">particles<br>
5650
5651
5652
5653
5654 </td>
5655
5656
5657
5658
5659
5660          </tr>
5661
5662
5663
5664
5665 <tr>
5666
5667
5668
5669
5670 <td style="vertical-align: top;"><span style="font-style: italic;">'all'</span><br>
5671
5672
5673
5674
5675 </td>
5676
5677
5678
5679
5680
5681            <td style="vertical-align: top;">all output quantities<br>
5682
5683
5684
5685
5686
5687            </td>
5688
5689
5690
5691
5692 </tr>
5693
5694
5695
5696
5697 
5698       
5699       
5700       
5701       
5702        </tbody> 
5703     
5704     
5705     
5706     
5707      </table>
5708
5709
5710
5711
5712 <br>
5713
5714
5715
5716
5717 <span style="font-weight: bold;">Example:</span><br>
5718
5719
5720
5721
5722
5723If all cross section data and the particle data shall be output in
5724double 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>
5725has to be assigned.<br>
5726
5727
5728
5729
5730 </td>
5731
5732
5733
5734
5735 </tr>
5736
5737
5738
5739
5740
5741    <tr>
5742
5743
5744
5745
5746 <td style="vertical-align: top;"> 
5747     
5748     
5749     
5750     
5751      <p><a name="npex"></a><b>npex</b></p>
5752
5753
5754
5755
5756 </td>
5757
5758
5759
5760
5761
5762      <td style="vertical-align: top;">I</td>
5763
5764
5765
5766
5767 <td style="vertical-align: top;"><br>
5768
5769
5770
5771
5772 </td>
5773
5774
5775
5776
5777 <td style="vertical-align: top;"> 
5778     
5779     
5780     
5781     
5782      <p>Number of processors
5783along x-direction of the virtual
5784processor
5785net.&nbsp; </p>
5786
5787
5788
5789
5790 
5791     
5792     
5793     
5794     
5795      <p>For parallel runs, the total
5796number of processors to be used
5797is given by
5798the <span style="font-weight: bold;">mrun</span>
5799option <a href="http://www.muk.uni-hannover.de/software/mrun_beschreibung.html#Opt-X">-X</a>.
5800By default, depending on the type of the parallel computer, PALM
5801generates a 1d processor
5802net (domain decomposition along x, <span style="font-weight: bold;">npey</span>
5803= <span style="font-style: italic;">1</span>) or a
58042d-net (this is
5805favored on machines with fast communication network). In case of a
58062d-net, it is tried to make it more or less square-shaped. If, for
5807example, 16 processors are assigned (-X 16), a 4 * 4 processor net is
5808generated (<span style="font-weight: bold;">npex</span>
5809= <span style="font-style: italic;">4</span>, <span style="font-weight: bold;">npey</span>
5810= <span style="font-style: italic;">4</span>).
5811This choice is optimal for square total domains (<a href="#nx">nx</a>
5812= <a href="#ny">ny</a>),
5813since then the number of ghost points at the lateral boundarys of
5814the subdomains is minimal. If <span style="font-weight: bold;">nx</span>
5815nd <span style="font-weight: bold;">ny</span>
5816differ extremely, the
5817processor 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>
5818
5819
5820
5821
5822
5823     
5824     
5825     
5826     
5827      <p><b>Important:</b> The value of <span style="font-weight: bold;">npex</span> * <span style="font-weight: bold;">npey</span> must exactly
5828correspond to the
5829value assigned by the <span style="font-weight: bold;">mrun</span>-option
5830      <tt>-X</tt>.
5831Otherwise the model run will abort with a corresponding error
5832message.&nbsp; <br>
5833
5834
5835
5836
5837
5838Additionally, the specification of <span style="font-weight: bold;">npex</span>
5839and <span style="font-weight: bold;">npey</span>
5840may of course
5841override the default setting for the domain decomposition (1d or 2d)
5842which may have a significant (negative) effect on the code performance.
5843      </p>
5844
5845
5846
5847
5848 </td>
5849
5850
5851
5852
5853 </tr>
5854
5855
5856
5857
5858 <tr>
5859
5860
5861
5862
5863 <td style="vertical-align: top;"> 
5864     
5865     
5866     
5867     
5868      <p><a name="npey"></a><b>npey</b></p>
5869
5870
5871
5872
5873
5874      </td>
5875
5876
5877
5878
5879 <td style="vertical-align: top;">I</td>
5880
5881
5882
5883
5884
5885      <td style="vertical-align: top;"><br>
5886
5887
5888
5889
5890 </td>
5891
5892
5893
5894
5895 <td style="vertical-align: top;"> 
5896     
5897     
5898     
5899     
5900      <p>Number of processors
5901along y-direction of the virtual
5902processor
5903net.&nbsp; </p>
5904
5905
5906
5907
5908 
5909     
5910     
5911     
5912     
5913      <p>For further information see <a href="#npex">npex</a>.</p>
5914
5915
5916
5917
5918 </td>
5919
5920
5921
5922
5923 </tr>
5924
5925
5926
5927
5928
5929    <tr>
5930
5931
5932
5933
5934 <td style="vertical-align: top;"> 
5935     
5936     
5937     
5938     
5939      <p><a name="nsor_ini"></a><b>nsor_ini</b></p>
5940
5941
5942
5943
5944
5945      </td>
5946
5947
5948
5949
5950 <td style="vertical-align: top;">I</td>
5951
5952
5953
5954
5955
5956      <td style="vertical-align: top;"><i>100</i></td>
5957
5958
5959
5960
5961
5962      <td style="vertical-align: top;"> 
5963     
5964     
5965     
5966     
5967      <p>Initial number
5968of iterations with the SOR algorithm.&nbsp; </p>
5969
5970
5971
5972
5973 
5974     
5975     
5976     
5977     
5978      <p>This
5979parameter is only effective if the SOR algorithm was
5980selected as the pressure solver scheme (<a href="chapter_4.2.html#psolver">psolver</a>
5981= <span style="font-style: italic;">'sor'</span>)
5982and specifies the
5983number of initial iterations of the SOR
5984scheme (at t = 0). The number of subsequent iterations at the following
5985timesteps is determined
5986with the parameter <a href="#nsor">nsor</a>.
5987Usually <b>nsor</b> &lt; <b>nsor_ini</b>,
5988since in each case
5989subsequent calls to <a href="chapter_4.2.html#psolver">psolver</a>
5990use the solution of the previous call as initial value. Suitable
5991test runs should determine whether sufficient convergence of the
5992solution is obtained with the default value and if necessary the value
5993of <b>nsor_ini</b> should be changed.</p>
5994
5995
5996
5997
5998 </td>
5999
6000
6001
6002
6003
6004    </tr>
6005
6006
6007
6008
6009 <tr>
6010
6011
6012
6013
6014 <td style="vertical-align: top;">
6015     
6016     
6017     
6018     
6019      <p><a name="nx"></a><b>nx</b></p>
6020
6021
6022
6023
6024
6025      </td>
6026
6027
6028
6029
6030 <td style="vertical-align: top;">I</td>
6031
6032
6033
6034
6035
6036      <td style="vertical-align: top;"><br>
6037
6038
6039
6040
6041 </td>
6042
6043
6044
6045
6046 <td style="vertical-align: top;"> 
6047     
6048     
6049     
6050     
6051      <p>Number of grid
6052points in x-direction.&nbsp; </p>
6053
6054
6055
6056
6057 
6058     
6059     
6060     
6061     
6062      <p>A value for this
6063parameter must be assigned. Since the lower
6064array bound in PALM
6065starts with i = 0, the actual number of grid points is equal to <b>nx+1</b>.
6066In case of cyclic boundary conditions along x, the domain size is (<b>nx+1</b>)*
6067      <a href="#dx">dx</a>.</p>
6068
6069
6070
6071
6072 
6073     
6074     
6075     
6076     
6077      <p>For
6078parallel runs, in case of <a href="#grid_matching">grid_matching</a>
6079= <span style="font-style: italic;">'strict'</span>,
6080      <b>nx+1</b> must
6081be an integral multiple
6082of the processor numbers (see <a href="#npex">npex</a>
6083and <a href="#npey">npey</a>)
6084along x- as well as along y-direction (due to data
6085transposition restrictions).</p>
6086
6087
6088
6089
6090     
6091     
6092     
6093     
6094      <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>
6095and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
6096
6097
6098
6099
6100 </td>
6101
6102
6103
6104
6105 </tr>
6106
6107
6108
6109
6110 <tr>
6111
6112
6113
6114
6115
6116      <td style="vertical-align: top;"> 
6117     
6118     
6119     
6120     
6121      <p><a name="ny"></a><b>ny</b></p>
6122
6123
6124
6125
6126
6127      </td>
6128
6129
6130
6131
6132 <td style="vertical-align: top;">I</td>
6133
6134
6135
6136
6137
6138      <td style="vertical-align: top;"><br>
6139
6140
6141
6142
6143 </td>
6144
6145
6146
6147
6148 <td style="vertical-align: top;"> 
6149     
6150     
6151     
6152     
6153      <p>Number of grid
6154points in y-direction.&nbsp; </p>
6155
6156
6157
6158
6159 
6160     
6161     
6162     
6163     
6164      <p>A value for this
6165parameter must be assigned. Since the lower
6166array bound in PALM starts with j = 0, the actual number of grid points
6167is equal to <b>ny+1</b>. In case of cyclic boundary
6168conditions along
6169y, the domain size is (<b>ny+1</b>) * <a href="#dy">dy</a>.</p>
6170
6171
6172
6173
6174
6175     
6176     
6177     
6178     
6179      <p>For parallel runs, in case of <a href="#grid_matching">grid_matching</a>
6180= <span style="font-style: italic;">'strict'</span>,
6181      <b>ny+1</b> must
6182be an integral multiple
6183of the processor numbers (see <a href="#npex">npex</a>
6184and <a href="#npey">npey</a>)&nbsp;
6185along y- as well as along x-direction (due to data
6186transposition restrictions).</p>
6187
6188
6189
6190
6191     
6192     
6193     
6194     
6195      <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>
6196and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
6197
6198
6199
6200
6201 </td>
6202
6203
6204
6205
6206 </tr>
6207
6208
6209
6210
6211 <tr>
6212
6213
6214
6215
6216
6217      <td style="vertical-align: top;"> 
6218     
6219     
6220     
6221     
6222      <p><a name="nz"></a><b>nz</b></p>
6223
6224
6225
6226
6227
6228      </td>
6229
6230
6231
6232
6233 <td style="vertical-align: top;">I</td>
6234
6235
6236
6237
6238
6239      <td style="vertical-align: top;"><br>
6240
6241
6242
6243
6244 </td>
6245
6246
6247
6248
6249 <td style="vertical-align: top;"> 
6250     
6251     
6252     
6253     
6254      <p>Number of grid
6255points in z-direction.&nbsp; </p>
6256
6257
6258
6259
6260 
6261     
6262     
6263     
6264     
6265      <p>A value for this
6266parameter must be assigned. Since the lower
6267array bound in PALM
6268starts with k = 0 and since one additional grid point is added at the
6269top boundary (k = <b>nz+1</b>), the actual number of grid
6270points is <b>nz+2</b>.
6271However, the prognostic equations are only solved up to <b>nz</b>
6272(u,
6273v)
6274or up to <b>nz-1</b> (w, scalar quantities). The top
6275boundary for u
6276and v is at k = <b>nz+1</b> (u, v) while at k = <b>nz</b>
6277for all
6278other quantities.&nbsp; </p>
6279
6280
6281
6282
6283 
6284     
6285     
6286     
6287     
6288      <p>For parallel
6289runs,&nbsp; in case of <a href="#grid_matching">grid_matching</a>
6290= <span style="font-style: italic;">'strict'</span>,
6291      <b>nz</b> must
6292be an integral multiple of
6293the number of processors in x-direction (due to data transposition
6294restrictions).</p>
6295
6296
6297
6298
6299 </td>
6300
6301
6302
6303
6304 </tr>
6305
6306
6307
6308
6309 <tr>
6310
6311
6312
6313
6314      <td style="vertical-align: top;"><a name="ocean"></a><span style="font-weight: bold;">ocean</span></td>
6315
6316
6317
6318
6319      <td style="vertical-align: top;">L</td>
6320
6321
6322
6323
6324      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
6325
6326
6327
6328
6329      <td style="vertical-align: top;">Parameter to switch on&nbsp;ocean runs.<br>
6330
6331
6332
6333
6334      <br>
6335
6336
6337
6338
6339By 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>
6340
6341
6342
6343
6344      <br>
6345
6346
6347
6348
6349     
6350     
6351     
6352     
6353      <ul>
6354
6355
6356
6357
6358        <li>An additional prognostic equation for salinity is solved.</li>
6359
6360
6361
6362
6363        <li>Potential temperature in buoyancy and stability-related terms is replaced by potential density.</li>
6364
6365
6366
6367
6368        <li>Potential
6369density is calculated from the equation of state for seawater after
6370each timestep, using the algorithm proposed by Jackett et al. (2006, J.
6371Atmos. Oceanic Technol., <span style="font-weight: bold;">23</span>, 1709-1728).<br>
6372
6373
6374
6375
6376So far, only the initial hydrostatic pressure is entered into this equation.</li>
6377
6378
6379
6380
6381        <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>
6382
6383
6384
6385
6386        <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>
6387
6388
6389
6390
6391        <li>Zero salinity flux is used as default boundary condition at the bottom of the sea.</li>
6392
6393
6394
6395
6396        <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>
6397
6398
6399
6400
6401     
6402     
6403     
6404     
6405      </ul>
6406
6407
6408
6409
6410      <br>
6411
6412
6413
6414
6415Relevant 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>
6416
6417
6418
6419
6420      <br>
6421
6422
6423
6424
6425Section <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>
6426
6427
6428
6429
6430      <br>
6431
6432
6433
6434
6435      <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>
6436
6437      </td>
6438
6439
6440
6441
6442    </tr>
6443
6444
6445
6446
6447    <tr>
6448
6449
6450
6451
6452 <td style="vertical-align: top;"> 
6453     
6454     
6455     
6456     
6457      <p><a name="omega"></a><b>omega</b></p>
6458
6459
6460
6461
6462
6463      </td>
6464
6465
6466
6467
6468 <td style="vertical-align: top;">R</td>
6469
6470
6471
6472
6473
6474      <td style="vertical-align: top;"><i>7.29212E-5</i></td>
6475
6476
6477
6478
6479
6480      <td style="vertical-align: top;"> 
6481     
6482     
6483     
6484     
6485      <p>Angular
6486velocity of the rotating system (in rad s<sup>-1</sup>).&nbsp;
6487      </p>
6488
6489
6490
6491
6492 
6493     
6494     
6495     
6496     
6497      <p>The angular velocity of the earth is set by
6498default. The
6499values
6500of the Coriolis parameters are calculated as:&nbsp; </p>
6501
6502
6503
6504
6505 
6506     
6507     
6508     
6509     
6510      <ul>
6511
6512
6513
6514
6515
6516       
6517       
6518       
6519       
6520        <p>f = 2.0 * <b>omega</b> * sin(<a href="#phi">phi</a>)&nbsp;
6521        <br>
6522
6523
6524
6525
6526f* = 2.0 * <b>omega</b> * cos(<a href="#phi">phi</a>)</p>
6527
6528
6529
6530
6531
6532     
6533     
6534     
6535     
6536      </ul>
6537
6538
6539
6540
6541 </td>
6542
6543
6544
6545
6546 </tr>
6547
6548
6549
6550
6551 <tr>
6552
6553
6554
6555
6556 <td style="vertical-align: top;"> 
6557     
6558     
6559     
6560     
6561      <p><a name="outflow_damping_width"></a><b>outflow_damping_width</b></p>
6562
6563
6564
6565
6566
6567      </td>
6568
6569
6570
6571
6572 <td style="vertical-align: top;">I</td>
6573
6574
6575
6576
6577
6578      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(20,
6579nx/2</span> or <span style="font-style: italic;">ny/2)</span></td>
6580
6581
6582
6583
6584
6585      <td style="vertical-align: top;">Width of
6586the damping range in the vicinity of the outflow (gridpoints).<br>
6587
6588
6589
6590
6591
6592      <br>
6593
6594
6595
6596
6597
6598When using non-cyclic lateral boundaries (see <a href="chapter_4.1.html#bc_lr">bc_lr</a>
6599or <a href="chapter_4.1.html#bc_ns">bc_ns</a>),
6600a smoothing has to be applied to the
6601velocity field in the vicinity of the outflow in order to suppress any
6602reflections of outgoing disturbances. This parameter controlls the
6603horizontal range to which the smoothing is applied. The range is given
6604in gridpoints counted from the respective outflow boundary. For further
6605details about the smoothing see parameter <a href="chapter_4.1.html#km_damp_max">km_damp_max</a>,
6606which defines the magnitude of the damping.</td>
6607
6608
6609
6610
6611 </tr>
6612
6613
6614
6615
6616
6617    <tr>
6618
6619
6620
6621
6622 <td style="vertical-align: top;"> 
6623     
6624     
6625     
6626     
6627      <p><a name="overshoot_limit_e"></a><b>overshoot_limit_e</b></p>
6628
6629
6630
6631
6632
6633      </td>
6634
6635
6636
6637
6638 <td style="vertical-align: top;">R</td>
6639
6640
6641
6642
6643
6644      <td style="vertical-align: top;"><i>0.0</i></td>
6645
6646
6647
6648
6649
6650      <td style="vertical-align: top;"> 
6651     
6652     
6653     
6654     
6655      <p>Allowed limit
6656for the overshooting of subgrid-scale TKE in
6657case that the upstream-spline scheme is switched on (in m<sup>2</sup>/s<sup>2</sup>).&nbsp;
6658      </p>
6659
6660
6661
6662
6663 
6664     
6665     
6666     
6667     
6668      <p>By deafult, if cut-off of overshoots is switched
6669on for the
6670upstream-spline scheme (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>),
6671no overshoots are permitted at all. If <b>overshoot_limit_e</b>
6672is given a non-zero value, overshoots with the respective
6673amplitude (both upward and downward) are allowed.&nbsp; </p>
6674
6675
6676
6677
6678
6679     
6680     
6681     
6682     
6683      <p>Only positive values are allowed for <b>overshoot_limit_e</b>.</p>
6684
6685
6686
6687
6688
6689      </td>
6690
6691
6692
6693
6694 </tr>
6695
6696
6697
6698
6699 <tr>
6700
6701
6702
6703
6704 <td style="vertical-align: top;"> 
6705     
6706     
6707     
6708     
6709      <p><a name="overshoot_limit_pt"></a><b>overshoot_limit_pt</b></p>
6710
6711
6712
6713
6714
6715      </td>
6716
6717
6718
6719
6720 <td style="vertical-align: top;">R</td>
6721
6722
6723
6724
6725
6726      <td style="vertical-align: top;"><i>0.0</i></td>
6727
6728
6729
6730
6731
6732      <td style="vertical-align: top;"> 
6733     
6734     
6735     
6736     
6737      <p>Allowed limit
6738for the overshooting of potential temperature in
6739case that the upstream-spline scheme is switched on (in K).&nbsp; </p>
6740
6741
6742
6743
6744
6745     
6746     
6747     
6748     
6749      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6750      </p>
6751
6752
6753
6754
6755 
6756     
6757     
6758     
6759     
6760      <p>Only positive values are allowed for <b>overshoot_limit_pt</b>.</p>
6761
6762
6763
6764
6765
6766      </td>
6767
6768
6769
6770
6771 </tr>
6772
6773
6774
6775
6776 <tr>
6777
6778
6779
6780
6781 <td style="vertical-align: top;"> 
6782     
6783     
6784     
6785     
6786      <p><a name="overshoot_limit_u"></a><b>overshoot_limit_u</b></p>
6787
6788
6789
6790
6791
6792      </td>
6793
6794
6795
6796
6797 <td style="vertical-align: top;">R</td>
6798
6799
6800
6801
6802
6803      <td style="vertical-align: top;"><i>0.0</i></td>
6804
6805
6806
6807
6808
6809      <td style="vertical-align: top;">Allowed limit for the
6810overshooting of
6811the u-component of velocity in case that the upstream-spline scheme is
6812switched on (in m/s).
6813     
6814     
6815     
6816     
6817      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6818      </p>
6819
6820
6821
6822
6823 
6824     
6825     
6826     
6827     
6828      <p>Only positive values are allowed for <b>overshoot_limit_u</b>.</p>
6829
6830
6831
6832
6833
6834      </td>
6835
6836
6837
6838
6839 </tr>
6840
6841
6842
6843
6844 <tr>
6845
6846
6847
6848
6849 <td style="vertical-align: top;"> 
6850     
6851     
6852     
6853     
6854      <p><a name="overshoot_limit_v"></a><b>overshoot_limit_v</b></p>
6855
6856
6857
6858
6859
6860      </td>
6861
6862
6863
6864
6865 <td style="vertical-align: top;">R</td>
6866
6867
6868
6869
6870
6871      <td style="vertical-align: top;"><i>0.0</i></td>
6872
6873
6874
6875
6876
6877      <td style="vertical-align: top;"> 
6878     
6879     
6880     
6881     
6882      <p>Allowed limit
6883for the overshooting of the v-component of
6884velocity in case that the upstream-spline scheme is switched on
6885(in m/s).&nbsp; </p>
6886
6887
6888
6889
6890 
6891     
6892     
6893     
6894     
6895      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6896      </p>
6897
6898
6899
6900
6901 
6902     
6903     
6904     
6905     
6906      <p>Only positive values are allowed for <b>overshoot_limit_v</b>.</p>
6907
6908
6909
6910
6911
6912      </td>
6913
6914
6915
6916
6917 </tr>
6918
6919
6920
6921
6922 <tr>
6923
6924
6925
6926
6927 <td style="vertical-align: top;"> 
6928     
6929     
6930     
6931     
6932      <p><a name="overshoot_limit_w"></a><b>overshoot_limit_w</b></p>
6933
6934
6935
6936
6937
6938      </td>
6939
6940
6941
6942
6943 <td style="vertical-align: top;">R</td>
6944
6945
6946
6947
6948
6949      <td style="vertical-align: top;"><i>0.0</i></td>
6950
6951
6952
6953
6954
6955      <td style="vertical-align: top;"> 
6956     
6957     
6958     
6959     
6960      <p>Allowed limit
6961for the overshooting of the w-component of
6962velocity in case that the upstream-spline scheme is switched on
6963(in m/s).&nbsp; </p>
6964
6965
6966
6967
6968 
6969     
6970     
6971     
6972     
6973      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
6974      </p>
6975
6976
6977
6978
6979 
6980     
6981     
6982     
6983     
6984      <p>Only positive values are permitted for <b>overshoot_limit_w</b>.</p>
6985
6986
6987
6988
6989
6990      </td>
6991
6992
6993
6994
6995 </tr>
6996
6997
6998
6999
7000 <tr>
7001
7002
7003
7004
7005 <td style="vertical-align: top;"> 
7006     
7007     
7008     
7009     
7010      <p><a name="passive_scalar"></a><b>passive_scalar</b></p>
7011
7012
7013
7014
7015
7016      </td>
7017
7018
7019
7020
7021 <td style="vertical-align: top;">L</td>
7022
7023
7024
7025
7026
7027      <td style="vertical-align: top;"><i>.F.</i></td>
7028
7029
7030
7031
7032
7033      <td style="vertical-align: top;"> 
7034     
7035     
7036     
7037     
7038      <p>Parameter to
7039switch on the prognostic equation for a passive
7040scalar. <br>
7041
7042
7043
7044
7045 </p>
7046
7047
7048
7049
7050 
7051     
7052     
7053     
7054     
7055      <p>The initial vertical profile
7056of s can be set via parameters <a href="#s_surface">s_surface</a>,
7057      <a href="#s_vertical_gradient">s_vertical_gradient</a>
7058and&nbsp; <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
7059Boundary conditions can be set via <a href="#s_surface_initial_change">s_surface_initial_change</a>
7060and <a href="#surface_scalarflux">surface_scalarflux</a>.&nbsp;
7061      </p>
7062
7063
7064
7065
7066 
7067     
7068     
7069     
7070     
7071      <p><b>Note:</b> <br>
7072
7073
7074
7075
7076
7077With <span style="font-weight: bold;">passive_scalar</span>
7078switched
7079on, the simultaneous use of humidity (see&nbsp;<a href="#humidity">humidity</a>)
7080is impossible.</p>
7081
7082
7083
7084
7085 </td>
7086
7087
7088
7089
7090 </tr>
7091
7092
7093
7094
7095 <tr>
7096
7097
7098
7099
7100 <td style="vertical-align: top;"> 
7101     
7102     
7103     
7104     
7105      <p><a name="phi"></a><b>phi</b></p>
7106
7107
7108
7109
7110
7111      </td>
7112
7113
7114
7115
7116 <td style="vertical-align: top;">R</td>
7117
7118
7119
7120
7121
7122      <td style="vertical-align: top;"><i>55.0</i></td>
7123
7124
7125
7126
7127
7128      <td style="vertical-align: top;"> 
7129     
7130     
7131     
7132     
7133      <p>Geographical
7134latitude (in degrees).&nbsp; </p>
7135
7136
7137
7138
7139 
7140     
7141     
7142     
7143     
7144      <p>The value of
7145this parameter determines the value of the
7146Coriolis parameters f and f*, provided that the angular velocity (see <a href="#omega">omega</a>)
7147is non-zero.</p>
7148
7149
7150
7151
7152 </td>
7153
7154
7155
7156
7157 </tr>
7158
7159
7160
7161
7162 <tr>
7163
7164
7165
7166
7167 <td style="vertical-align: top;"> 
7168     
7169     
7170     
7171     
7172      <p><a name="prandtl_layer"></a><b>prandtl_layer</b></p>
7173
7174
7175
7176
7177
7178      </td>
7179
7180
7181
7182
7183 <td style="vertical-align: top;">L</td>
7184
7185
7186
7187
7188
7189      <td style="vertical-align: top;"><i>.T.</i></td>
7190
7191
7192
7193
7194
7195      <td style="vertical-align: top;"> 
7196     
7197     
7198     
7199     
7200      <p>Parameter to
7201switch on a Prandtl layer.&nbsp; </p>
7202
7203
7204
7205
7206 
7207     
7208     
7209     
7210     
7211      <p>By default,
7212a Prandtl layer is switched on at the bottom
7213boundary between z = 0 and z = 0.5 * <a href="#dz">dz</a>
7214(the first computational grid point above ground for u, v and the
7215scalar quantities).
7216In this case, at the bottom boundary, free-slip conditions for u and v
7217(see <a href="#bc_uv_b">bc_uv_b</a>)
7218are not allowed. Likewise, laminar
7219simulations with constant eddy diffusivities (<a href="#km_constant">km_constant</a>)
7220are forbidden.&nbsp; </p>
7221
7222
7223
7224
7225 
7226     
7227     
7228     
7229     
7230      <p>With Prandtl-layer
7231switched off, the TKE boundary condition <a href="#bc_e_b">bc_e_b</a>
7232= '<i>(u*)**2+neumann'</i> must not be used and is
7233automatically
7234changed to <i>'neumann'</i> if necessary.&nbsp; Also,
7235the pressure
7236boundary condition <a href="#bc_p_b">bc_p_b</a>
7237= <i>'neumann+inhomo'</i>&nbsp; is not allowed. </p>
7238
7239
7240
7241
7242
7243     
7244     
7245     
7246     
7247      <p>The roughness length is declared via the parameter <a href="#roughness_length">roughness_length</a>.</p>
7248
7249
7250
7251
7252
7253      </td>
7254
7255
7256
7257
7258 </tr>
7259
7260
7261
7262
7263 <tr>
7264
7265
7266
7267
7268 <td style="vertical-align: top;"> 
7269     
7270     
7271     
7272     
7273      <p><a name="precipitation"></a><b>precipitation</b></p>
7274
7275
7276
7277
7278
7279      </td>
7280
7281
7282
7283
7284 <td style="vertical-align: top;">L</td>
7285
7286
7287
7288
7289
7290      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
7291
7292
7293
7294
7295 <td style="vertical-align: top;"> 
7296     
7297     
7298     
7299     
7300      <p>Parameter to switch
7301on the precipitation scheme.<br>
7302
7303
7304
7305
7306 </p>
7307
7308
7309
7310
7311 
7312     
7313     
7314     
7315     
7316      <p>For
7317precipitation processes PALM uses a simplified Kessler
7318scheme. This scheme only considers the
7319so-called autoconversion, that means the generation of rain water by
7320coagulation of cloud drops among themselves. Precipitation begins and
7321is immediately removed from the flow as soon as the liquid water
7322content exceeds the critical value of 0.5 g/kg.</p>
7323
7324
7325
7326
7327     
7328     
7329     
7330     
7331      <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>
7332
7333
7334
7335
7336 </td>
7337
7338
7339
7340
7341 </tr>
7342
7343
7344
7345
7346
7347    <tr>
7348
7349
7350
7351
7352      <td style="vertical-align: top;"><a name="pt_reference"></a><span style="font-weight: bold;">pt_reference</span></td>
7353
7354
7355
7356
7357      <td style="vertical-align: top;">R</td>
7358
7359
7360
7361
7362      <td style="vertical-align: top;"><span style="font-style: italic;">use horizontal average as
7363refrence</span></td>
7364
7365
7366
7367
7368      <td style="vertical-align: top;">Reference
7369temperature to be used in all buoyancy terms (in K).<br>
7370
7371
7372
7373
7374      <br>
7375
7376
7377
7378
7379By
7380default, the instantaneous horizontal average over the total model
7381domain is used.<br>
7382
7383
7384
7385
7386      <br>
7387
7388
7389
7390
7391      <span style="font-weight: bold;">Attention:</span><br>
7392
7393
7394
7395
7396In 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>
7397
7398
7399
7400
7401    </tr>
7402
7403
7404
7405
7406    <tr>
7407
7408
7409
7410
7411 <td style="vertical-align: top;"> 
7412     
7413     
7414     
7415     
7416      <p><a name="pt_surface"></a><b>pt_surface</b></p>
7417
7418
7419
7420
7421
7422      </td>
7423
7424
7425
7426
7427 <td style="vertical-align: top;">R</td>
7428
7429
7430
7431
7432
7433      <td style="vertical-align: top;"><i>300.0</i></td>
7434
7435
7436
7437
7438
7439      <td style="vertical-align: top;"> 
7440     
7441     
7442     
7443     
7444      <p>Surface
7445potential temperature (in K).&nbsp; </p>
7446
7447
7448
7449
7450 
7451     
7452     
7453     
7454     
7455      <p>This
7456parameter assigns the value of the potential temperature
7457      <span style="font-weight: bold;">pt</span> at the surface (k=0)<b>.</b> Starting from this value,
7458the
7459initial vertical temperature profile is constructed with <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7460and <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level
7461      </a>.
7462This profile is also used for the 1d-model as a stationary profile.</p>
7463
7464
7465
7466
7467     
7468     
7469     
7470     
7471      <p><span style="font-weight: bold;">Attention:</span><br>
7472
7473
7474
7475
7476In case of ocean runs (see <a href="#ocean">ocean</a>),
7477this parameter gives the temperature value at the sea surface, which is
7478at k=nzt. The profile is then constructed from the surface down to the
7479bottom of the model.</p>
7480
7481
7482
7483
7484
7485      </td>
7486
7487
7488
7489
7490 </tr>
7491
7492
7493
7494
7495 <tr>
7496
7497
7498
7499
7500 <td style="vertical-align: top;"> 
7501     
7502     
7503     
7504     
7505      <p><a name="pt_surface_initial_change"></a><b>pt_surface_initial</b>
7506      <br>
7507
7508
7509
7510
7511 <b>_change</b></p>
7512
7513
7514
7515
7516 </td>
7517
7518
7519
7520
7521 <td style="vertical-align: top;">R</td>
7522
7523
7524
7525
7526 <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
7527
7528
7529
7530
7531 </td>
7532
7533
7534
7535
7536
7537      <td style="vertical-align: top;"> 
7538     
7539     
7540     
7541     
7542      <p>Change in
7543surface temperature to be made at the beginning of
7544the 3d run
7545(in K).&nbsp; </p>
7546
7547
7548
7549
7550 
7551     
7552     
7553     
7554     
7555      <p>If <b>pt_surface_initial_change</b>
7556is set to a non-zero
7557value, the near surface sensible heat flux is not allowed to be given
7558simultaneously (see <a href="#surface_heatflux">surface_heatflux</a>).</p>
7559
7560
7561
7562
7563
7564      </td>
7565
7566
7567
7568
7569 </tr>
7570
7571
7572
7573
7574 <tr>
7575
7576
7577
7578
7579 <td style="vertical-align: top;"> 
7580     
7581     
7582     
7583     
7584      <p><a name="pt_vertical_gradient"></a><b>pt_vertical_gradient</b></p>
7585
7586
7587
7588
7589
7590      </td>
7591
7592
7593
7594
7595 <td style="vertical-align: top;">R (10)</td>
7596
7597
7598
7599
7600
7601      <td style="vertical-align: top;"><i>10 * 0.0</i></td>
7602
7603
7604
7605
7606
7607      <td style="vertical-align: top;"> 
7608     
7609     
7610     
7611     
7612      <p>Temperature
7613gradient(s) of the initial temperature profile (in
7614K
7615/ 100 m).&nbsp; </p>
7616
7617
7618
7619
7620 
7621     
7622     
7623     
7624     
7625      <p>This temperature gradient
7626holds starting from the height&nbsp;
7627level defined by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>
7628(precisely: for all uv levels k where zu(k) &gt;
7629pt_vertical_gradient_level,
7630pt_init(k) is set: pt_init(k) = pt_init(k-1) + dzu(k) * <b>pt_vertical_gradient</b>)
7631up to the top boundary or up to the next height level defined
7632by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>.
7633A total of 10 different gradients for 11 height intervals (10 intervals
7634if <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>(1)
7635= <i>0.0</i>) can be assigned. The surface temperature is
7636assigned via <a href="#pt_surface">pt_surface</a>.&nbsp;
7637      </p>
7638
7639
7640
7641
7642 
7643     
7644     
7645     
7646     
7647      <p>Example:&nbsp; </p>
7648
7649
7650
7651
7652 
7653     
7654     
7655     
7656     
7657      <ul>
7658
7659
7660
7661
7662 
7663       
7664       
7665       
7666       
7667        <p><b>pt_vertical_gradient</b>
7668= <i>1.0</i>, <i>0.5</i>,&nbsp; <br>
7669
7670
7671
7672
7673
7674        <b>pt_vertical_gradient_level</b> = <i>500.0</i>,
7675        <i>1000.0</i>,</p>
7676
7677
7678
7679
7680 
7681     
7682     
7683     
7684     
7685      </ul>
7686
7687
7688
7689
7690 
7691     
7692     
7693     
7694     
7695      <p>That
7696defines the temperature profile to be neutrally
7697stratified
7698up to z = 500.0 m with a temperature given by <a href="#pt_surface">pt_surface</a>.
7699For 500.0 m &lt; z &lt;= 1000.0 m the temperature gradient is
77001.0 K /
7701100 m and for z &gt; 1000.0 m up to the top boundary it is
77020.5 K / 100 m (it is assumed that the assigned height levels correspond
7703with uv levels).</p>
7704
7705
7706
7707
7708     
7709     
7710     
7711     
7712      <p><span style="font-weight: bold;">Attention:</span><br>
7713
7714
7715
7716
7717In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>),
7718the profile is constructed like described above, but starting from the
7719sea surface (k=nzt) down to the bottom boundary of the model. Height
7720levels 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>
7721
7722
7723
7724
7725 </td>
7726
7727
7728
7729
7730 </tr>
7731
7732
7733
7734
7735 <tr>
7736
7737
7738
7739
7740 <td style="vertical-align: top;"> 
7741     
7742     
7743     
7744     
7745      <p><a name="pt_vertical_gradient_level"></a><b>pt_vertical_gradient</b>
7746      <br>
7747
7748
7749
7750
7751 <b>_level</b></p>
7752
7753
7754
7755
7756 </td>
7757
7758
7759
7760
7761 <td style="vertical-align: top;">R (10)</td>
7762
7763
7764
7765
7766 <td style="vertical-align: top;"> 
7767     
7768     
7769     
7770     
7771      <p><i>10 *</i>&nbsp;
7772      <span style="font-style: italic;">0.0</span><br>
7773
7774
7775
7776
7777
7778      </p>
7779
7780
7781
7782
7783 </td>
7784
7785
7786
7787
7788 <td style="vertical-align: top;">
7789     
7790     
7791     
7792     
7793      <p>Height level from which on the temperature gradient defined by
7794      <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7795is effective (in m).&nbsp; </p>
7796
7797
7798
7799
7800 
7801     
7802     
7803     
7804     
7805      <p>The height levels have to be assigned in ascending order. The
7806default values result in a neutral stratification regardless of the
7807values of <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
7808(unless the top boundary of the model is higher than 100000.0 m).
7809For the piecewise construction of temperature profiles see <a href="#pt_vertical_gradient">pt_vertical_gradient</a>.</p>
7810
7811
7812
7813
7814      <span style="font-weight: bold;">Attention:</span><br>
7815
7816
7817
7818
7819In 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.
7820      </td>
7821
7822
7823
7824
7825 </tr>
7826
7827
7828
7829
7830 <tr>
7831
7832
7833
7834
7835 <td style="vertical-align: top;"> 
7836     
7837     
7838     
7839     
7840      <p><a name="q_surface"></a><b>q_surface</b></p>
7841
7842
7843
7844
7845
7846      </td>
7847
7848
7849
7850
7851 <td style="vertical-align: top;">R</td>
7852
7853
7854
7855
7856
7857      <td style="vertical-align: top;"><i>0.0</i></td>
7858
7859
7860
7861
7862
7863      <td style="vertical-align: top;"> 
7864     
7865     
7866     
7867     
7868      <p>Surface
7869specific humidity / total water content (kg/kg).&nbsp; </p>
7870
7871
7872
7873
7874 
7875     
7876     
7877     
7878     
7879      <p>This
7880parameter assigns the value of the specific humidity q at
7881the surface (k=0).&nbsp; Starting from this value, the initial
7882humidity
7883profile is constructed with&nbsp; <a href="#q_vertical_gradient">q_vertical_gradient</a>
7884and <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
7885This profile is also used for the 1d-model as a stationary profile.</p>
7886
7887
7888
7889
7890
7891      </td>
7892
7893
7894
7895
7896 </tr>
7897
7898
7899
7900
7901 <tr>
7902
7903
7904
7905
7906 <td style="vertical-align: top;"> 
7907     
7908     
7909     
7910     
7911      <p><a name="q_surface_initial_change"></a><b>q_surface_initial</b>
7912      <br>
7913
7914
7915
7916
7917 <b>_change</b></p>
7918
7919
7920
7921
7922 </td>
7923
7924
7925
7926
7927 <td style="vertical-align: top;">R<br>
7928
7929
7930
7931
7932 </td>
7933
7934
7935
7936
7937 <td style="vertical-align: top;"><i>0.0</i></td>
7938
7939
7940
7941
7942
7943      <td style="vertical-align: top;"> 
7944     
7945     
7946     
7947     
7948      <p>Change in
7949surface specific humidity / total water content to
7950be made at the beginning
7951of the 3d run (kg/kg).&nbsp; </p>
7952
7953
7954
7955
7956 
7957     
7958     
7959     
7960     
7961      <p>If <b>q_surface_initial_change</b><i>
7962      </i>is set to a
7963non-zero value the
7964near surface latent heat flux (water flux) is not allowed to be given
7965simultaneously (see <a href="#surface_waterflux">surface_waterflux</a>).</p>
7966
7967
7968
7969
7970
7971      </td>
7972
7973
7974
7975
7976 </tr>
7977
7978
7979
7980
7981 <tr>
7982
7983
7984
7985
7986 <td style="vertical-align: top;"> 
7987     
7988     
7989     
7990     
7991      <p><a name="q_vertical_gradient"></a><b>q_vertical_gradient</b></p>
7992
7993
7994
7995
7996
7997      </td>
7998
7999
8000
8001
8002 <td style="vertical-align: top;">R (10)</td>
8003
8004
8005
8006
8007
8008      <td style="vertical-align: top;"><i>10 * 0.0</i></td>
8009
8010
8011
8012
8013
8014      <td style="vertical-align: top;"> 
8015     
8016     
8017     
8018     
8019      <p>Humidity
8020gradient(s) of the initial humidity profile
8021(in 1/100 m).&nbsp; </p>
8022
8023
8024
8025
8026 
8027     
8028     
8029     
8030     
8031      <p>This humidity gradient
8032holds starting from the height
8033level&nbsp; defined by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>
8034(precisely: for all uv levels k, where zu(k) &gt;
8035q_vertical_gradient_level,
8036q_init(k) is set: q_init(k) = q_init(k-1) + dzu(k) * <b>q_vertical_gradient</b>)
8037up to the top boundary or up to the next height level defined
8038by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
8039A total of 10 different gradients for 11 height intervals (10 intervals
8040if <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>(1)
8041= <i>0.0</i>) can be asigned. The surface humidity is
8042assigned
8043via <a href="#q_surface">q_surface</a>. </p>
8044
8045
8046
8047
8048
8049     
8050     
8051     
8052     
8053      <p>Example:&nbsp; </p>
8054
8055
8056
8057
8058 
8059     
8060     
8061     
8062     
8063      <ul>
8064
8065
8066
8067
8068 
8069       
8070       
8071       
8072       
8073        <p><b>q_vertical_gradient</b>
8074= <i>0.001</i>, <i>0.0005</i>,&nbsp; <br>
8075
8076
8077
8078
8079
8080        <b>q_vertical_gradient_level</b> = <i>500.0</i>,
8081        <i>1000.0</i>,</p>
8082
8083
8084
8085
8086 
8087     
8088     
8089     
8090     
8091      </ul>
8092
8093
8094
8095
8096
8097That defines the humidity to be constant with height up to z =
8098500.0
8099m with a
8100value given by <a href="#q_surface">q_surface</a>.
8101For 500.0 m &lt; z &lt;= 1000.0 m the humidity gradient is
81020.001 / 100
8103m and for z &gt; 1000.0 m up to the top boundary it is
81040.0005 / 100 m (it is assumed that the assigned height levels
8105correspond with uv
8106levels). </td>
8107
8108
8109
8110
8111 </tr>
8112
8113
8114
8115
8116 <tr>
8117
8118
8119
8120
8121 <td style="vertical-align: top;"> 
8122     
8123     
8124     
8125     
8126      <p><a name="q_vertical_gradient_level"></a><b>q_vertical_gradient</b>
8127      <br>
8128
8129
8130
8131
8132 <b>_level</b></p>
8133
8134
8135
8136
8137 </td>
8138
8139
8140
8141
8142 <td style="vertical-align: top;">R (10)</td>
8143
8144
8145
8146
8147 <td style="vertical-align: top;"> 
8148     
8149     
8150     
8151     
8152      <p><i>10 *</i>&nbsp;
8153      <i>0.0</i></p>
8154
8155
8156
8157
8158 </td>
8159
8160
8161
8162
8163 <td style="vertical-align: top;"> 
8164     
8165     
8166     
8167     
8168      <p>Height level from
8169which on the humidity gradient defined by <a href="#q_vertical_gradient">q_vertical_gradient</a>
8170is effective (in m).&nbsp; </p>
8171
8172
8173
8174
8175 
8176     
8177     
8178     
8179     
8180      <p>The height levels
8181are to be assigned in ascending order. The
8182default values result in a humidity constant with height regardless of
8183the values of <a href="#q_vertical_gradient">q_vertical_gradient</a>
8184(unless the top boundary of the model is higher than 100000.0 m). For
8185the piecewise construction of humidity profiles see <a href="#q_vertical_gradient">q_vertical_gradient</a>.</p>
8186
8187
8188
8189
8190
8191      </td>
8192
8193
8194
8195
8196 </tr>
8197
8198
8199
8200
8201 <tr>
8202
8203
8204
8205
8206 <td style="vertical-align: top;"> 
8207     
8208     
8209     
8210     
8211      <p><a name="radiation"></a><b>radiation</b></p>
8212
8213
8214
8215
8216
8217      </td>
8218
8219
8220
8221
8222 <td style="vertical-align: top;">L</td>
8223
8224
8225
8226
8227
8228      <td style="vertical-align: top;"><i>.F.</i></td>
8229
8230
8231
8232
8233
8234      <td style="vertical-align: top;"> 
8235     
8236     
8237     
8238     
8239      <p>Parameter to
8240switch on longwave radiation cooling at
8241cloud-tops.&nbsp; </p>
8242
8243
8244
8245
8246 
8247     
8248     
8249     
8250     
8251      <p>Long-wave radiation
8252processes are parameterized by the
8253effective emissivity, which considers only the absorption and emission
8254of long-wave radiation at cloud droplets. The radiation scheme can be
8255used only with <a href="#cloud_physics">cloud_physics</a>
8256= .TRUE. .</p>
8257
8258
8259
8260
8261 </td>
8262
8263
8264
8265
8266 </tr>
8267
8268
8269
8270
8271 <tr>
8272
8273
8274
8275
8276 <td style="vertical-align: top;"> 
8277     
8278     
8279     
8280     
8281      <p><a name="random_generator"></a><b>random_generator</b></p>
8282
8283
8284
8285
8286
8287      </td>
8288
8289
8290
8291
8292 <td style="vertical-align: top;">C * 20</td>
8293
8294
8295
8296
8297
8298      <td style="vertical-align: top;"> 
8299     
8300     
8301     
8302     
8303      <p><i>'numerical</i><br>
8304
8305
8306
8307
8308
8309      <i>recipes'</i></p>
8310
8311
8312
8313
8314 </td>
8315
8316
8317
8318
8319 <td style="vertical-align: top;"> 
8320     
8321     
8322     
8323     
8324      <p>Random number
8325generator to be used for creating uniformly
8326distributed random numbers. <br>
8327
8328
8329
8330
8331 </p>
8332
8333
8334
8335
8336 
8337     
8338     
8339     
8340     
8341      <p>It is
8342used if random perturbations are to be imposed on the
8343velocity field or on the surface heat flux field (see <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>
8344and <a href="chapter_4.2.html#random_heatflux">random_heatflux</a>).
8345By default, the "Numerical Recipes" random number generator is used.
8346This one provides exactly the same order of random numbers on all
8347different machines and should be used in particular for comparison runs.<br>
8348
8349
8350
8351
8352
8353      <br>
8354
8355
8356
8357
8358
8359Besides, a system-specific generator is available ( <b>random_generator</b>
8360= <i>'system-specific')</i> which should particularly be
8361used for runs
8362on vector parallel computers (NEC), because the default generator
8363cannot be vectorized and therefore significantly drops down the code
8364performance on these machines.<br>
8365
8366
8367
8368
8369 </p>
8370
8371
8372
8373
8374 <span style="font-weight: bold;">Note:</span><br>
8375
8376
8377
8378
8379
8380Results from two otherwise identical model runs will not be comparable
8381one-to-one if they used different random number generators.</td>
8382
8383
8384
8385
8386 </tr>
8387
8388
8389
8390
8391
8392    <tr>
8393
8394
8395
8396
8397 <td style="vertical-align: top;"> 
8398     
8399     
8400     
8401     
8402      <p><a name="random_heatflux"></a><b>random_heatflux</b></p>
8403
8404
8405
8406
8407
8408      </td>
8409
8410
8411
8412
8413 <td style="vertical-align: top;">L</td>
8414
8415
8416
8417
8418
8419      <td style="vertical-align: top;"><i>.F.</i></td>
8420
8421
8422
8423
8424
8425      <td style="vertical-align: top;"> 
8426     
8427     
8428     
8429     
8430      <p>Parameter to
8431impose random perturbations on the internal two-dimensional near
8432surface heat flux field <span style="font-style: italic;">shf</span>.
8433      <br>
8434
8435
8436
8437
8438 </p>
8439
8440
8441
8442
8443If a near surface heat flux is used as bottom
8444boundary
8445condition (see <a href="#surface_heatflux">surface_heatflux</a>),
8446it is by default assumed to be horizontally homogeneous. Random
8447perturbations can be imposed on the internal
8448two-dimensional&nbsp;heat flux field <span style="font-style: italic;">shf</span> by assigning <b>random_heatflux</b>
8449= <i>.T.</i>. The disturbed heat flux field is calculated
8450by
8451multiplying the
8452values at each mesh point with a normally distributed random number
8453with a mean value and standard deviation of 1. This is repeated after
8454every timestep.<br>
8455
8456
8457
8458
8459 <br>
8460
8461
8462
8463
8464
8465In case of a non-flat <a href="#topography">topography</a>,&nbsp;assigning
8466      <b>random_heatflux</b>
8467= <i>.T.</i> imposes random perturbations on the
8468combined&nbsp;heat
8469flux field <span style="font-style: italic;">shf</span>
8470composed of <a href="#surface_heatflux">surface_heatflux</a>
8471at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
8472at the topography top face.</td>
8473
8474
8475
8476
8477 </tr>
8478
8479
8480
8481
8482 <tr>
8483
8484
8485
8486
8487 <td style="vertical-align: top;"> 
8488     
8489     
8490     
8491     
8492      <p><a name="rif_max"></a><b>rif_max</b></p>
8493
8494
8495
8496
8497
8498      </td>
8499
8500
8501
8502
8503 <td style="vertical-align: top;">R</td>
8504
8505
8506
8507
8508
8509      <td style="vertical-align: top;"><i>1.0</i></td>
8510
8511
8512
8513
8514
8515      <td style="vertical-align: top;"> 
8516     
8517     
8518     
8519     
8520      <p>Upper limit of
8521the flux-Richardson number.&nbsp; </p>
8522
8523
8524
8525
8526 
8527     
8528     
8529     
8530     
8531      <p>With the
8532Prandtl layer switched on (see <a href="#prandtl_layer">prandtl_layer</a>),
8533flux-Richardson numbers (rif) are calculated for z=z<sub>p</sub>
8534(k=1)
8535in the 3d-model (in the 1d model for all heights). Their values in
8536particular determine the
8537values of the friction velocity (1d- and 3d-model) and the values of
8538the eddy diffusivity (1d-model). With small wind velocities at the
8539Prandtl layer top or small vertical wind shears in the 1d-model, rif
8540can take up unrealistic large values. They are limited by an upper (<span style="font-weight: bold;">rif_max</span>) and lower
8541limit (see <a href="#rif_min">rif_min</a>)
8542for the flux-Richardson number. The condition <b>rif_max</b>
8543&gt; <b>rif_min</b>
8544must be met.</p>
8545
8546
8547
8548
8549 </td>
8550
8551
8552
8553
8554 </tr>
8555
8556
8557
8558
8559 <tr>
8560
8561
8562
8563
8564 <td style="vertical-align: top;"> 
8565     
8566     
8567     
8568     
8569      <p><a name="rif_min"></a><b>rif_min</b></p>
8570
8571
8572
8573
8574
8575      </td>
8576
8577
8578
8579
8580 <td style="vertical-align: top;">R</td>
8581
8582
8583
8584
8585
8586      <td style="vertical-align: top;"><i>- 5.0</i></td>
8587
8588
8589
8590
8591
8592      <td style="vertical-align: top;"> 
8593     
8594     
8595     
8596     
8597      <p>Lower limit of
8598the flux-Richardson number.&nbsp; </p>
8599
8600
8601
8602
8603 
8604     
8605     
8606     
8607     
8608      <p>For further
8609explanations see <a href="#rif_max">rif_max</a>.
8610The condition <b>rif_max</b> &gt; <b>rif_min </b>must
8611be met.</p>
8612
8613
8614
8615
8616 </td>
8617
8618
8619
8620
8621 </tr>
8622
8623
8624
8625
8626 <tr>
8627
8628
8629
8630
8631 <td style="vertical-align: top;"> 
8632     
8633     
8634     
8635     
8636      <p><a name="roughness_length"></a><b>roughness_length</b></p>
8637
8638
8639
8640
8641
8642      </td>
8643
8644
8645
8646
8647 <td style="vertical-align: top;">R</td>
8648
8649
8650
8651
8652
8653      <td style="vertical-align: top;"><i>0.1</i></td>
8654
8655
8656
8657
8658
8659      <td style="vertical-align: top;"> 
8660     
8661     
8662     
8663     
8664      <p>Roughness
8665length (in m).&nbsp; </p>
8666
8667
8668
8669
8670 
8671     
8672     
8673     
8674     
8675      <p>This parameter is
8676effective only in case that a Prandtl layer
8677is switched
8678on (see <a href="#prandtl_layer">prandtl_layer</a>).</p>
8679
8680
8681
8682
8683
8684      </td>
8685
8686
8687
8688
8689 </tr>
8690
8691
8692
8693
8694 <tr>
8695
8696
8697
8698
8699      <td style="vertical-align: top;"><a name="sa_surface"></a><span style="font-weight: bold;">sa_surface</span></td>
8700
8701
8702
8703
8704      <td style="vertical-align: top;">R</td>
8705
8706
8707
8708
8709      <td style="vertical-align: top;"><span style="font-style: italic;">35.0</span></td>
8710
8711
8712
8713
8714      <td style="vertical-align: top;"> 
8715     
8716     
8717     
8718     
8719      <p>Surface salinity (in psu).&nbsp;</p>
8720
8721
8722
8723
8724This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).
8725     
8726     
8727     
8728     
8729      <p>This
8730parameter 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,
8731the
8732initial 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>
8733and&nbsp;<a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level
8734      </a>.</p>
8735
8736
8737
8738
8739      </td>
8740
8741
8742
8743
8744    </tr>
8745
8746
8747
8748
8749    <tr>
8750
8751
8752
8753
8754      <td style="vertical-align: top;"><a name="sa_vertical_gradient"></a><span style="font-weight: bold;">sa_vertical_gradient</span></td>
8755
8756
8757
8758
8759      <td style="vertical-align: top;">R(10)</td>
8760
8761
8762
8763
8764      <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
8765
8766
8767
8768
8769      <td style="vertical-align: top;">
8770     
8771     
8772     
8773     
8774      <p>Salinity gradient(s) of the initial salinity profile (in psu
8775/ 100 m).&nbsp; </p>
8776
8777
8778
8779
8780 
8781     
8782     
8783     
8784     
8785      <p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
8786
8787
8788
8789
8790     
8791     
8792     
8793     
8794      <p>This salinity gradient
8795holds starting from the height&nbsp;
8796level defined by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>
8797(precisely: for all uv levels k where zu(k) &lt;
8798sa_vertical_gradient_level, sa_init(k) is set: sa_init(k) =
8799sa_init(k+1) - dzu(k+1) * <b>sa_vertical_gradient</b>) down to the bottom boundary or down to the next height level defined
8800by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>.
8801A total of 10 different gradients for 11 height intervals (10 intervals
8802if <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>(1)
8803= <i>0.0</i>) can be assigned. The surface salinity at k=nzt is
8804assigned via <a href="chapter_4.1.html#sa_surface">sa_surface</a>.&nbsp;
8805      </p>
8806
8807
8808
8809
8810 
8811     
8812     
8813     
8814     
8815      <p>Example:&nbsp; </p>
8816
8817
8818
8819
8820 
8821     
8822     
8823     
8824     
8825      <ul>
8826
8827
8828
8829
8830       
8831       
8832       
8833       
8834        <p><b>sa_vertical_gradient</b>
8835= <i>1.0</i>, <i>0.5</i>,&nbsp; <br>
8836
8837
8838
8839
8840
8841        <b>sa_vertical_gradient_level</b> = <i>-500.0</i>,
8842-<i>1000.0</i>,</p>
8843
8844
8845
8846
8847     
8848     
8849     
8850     
8851      </ul>
8852
8853
8854
8855
8856 
8857     
8858     
8859     
8860     
8861      <p>That
8862defines 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>.
8863For -500.0 m &lt; z &lt;= -1000.0 m the salinity gradient is
88641.0 psu /
8865100 m and for z &lt; -1000.0 m down to the bottom boundary it is
88660.5 psu / 100 m (it is assumed that the assigned height levels correspond
8867with uv levels).</p>
8868
8869
8870
8871
8872      </td>
8873
8874
8875
8876
8877    </tr>
8878
8879
8880
8881
8882    <tr>
8883
8884
8885
8886
8887      <td style="vertical-align: top;"><a name="sa_vertical_gradient_level"></a><span style="font-weight: bold;">sa_vertical_gradient_level</span></td>
8888
8889
8890
8891
8892      <td style="vertical-align: top;">R(10)</td>
8893
8894
8895
8896
8897      <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
8898
8899
8900
8901
8902      <td style="vertical-align: top;">
8903     
8904     
8905     
8906     
8907      <p>Height level from which on the salinity gradient defined by <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
8908is effective (in m).&nbsp; </p>
8909
8910
8911
8912
8913 
8914     
8915     
8916     
8917     
8918      <p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
8919
8920
8921
8922
8923     
8924     
8925     
8926     
8927      <p>The height levels have to be assigned in descending order. The
8928default values result in a constant salinity profile regardless of the
8929values of <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
8930(unless the bottom boundary of the model is lower than -100000.0 m).
8931For the piecewise construction of salinity profiles see <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>.</p>
8932
8933
8934
8935
8936      </td>
8937
8938
8939
8940
8941    </tr>
8942
8943
8944
8945
8946    <tr>
8947
8948
8949
8950
8951 <td style="vertical-align: top;"> 
8952     
8953     
8954     
8955     
8956      <p><a name="scalar_advec"></a><b>scalar_advec</b></p>
8957
8958
8959
8960
8961
8962      </td>
8963
8964
8965
8966
8967 <td style="vertical-align: top;">C * 10</td>
8968
8969
8970
8971
8972
8973      <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
8974
8975
8976
8977
8978
8979      <td style="vertical-align: top;"> 
8980     
8981     
8982     
8983     
8984      <p>Advection
8985scheme to be used for the scalar quantities.&nbsp; </p>
8986
8987
8988
8989
8990 
8991     
8992     
8993     
8994     
8995      <p>The
8996user can choose between the following schemes:<br>
8997
8998
8999
9000
9001 </p>
9002
9003
9004
9005
9006 
9007     
9008     
9009     
9010     
9011      <p><span style="font-style: italic;">'pw-scheme'</span><br>
9012
9013
9014
9015
9016
9017      </p>
9018
9019
9020
9021
9022 
9023     
9024     
9025     
9026     
9027      <div style="margin-left: 40px;">The scheme of
9028Piascek and
9029Williams (1970, J. Comp. Phys., 6,
9030392-405) with central differences in the form C3 is used.<br>
9031
9032
9033
9034
9035
9036If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
9037= <span style="font-style: italic;">'leapfrog+euler'</span>
9038the
9039advection scheme is - for the Euler-timestep - automatically switched
9040to an upstream-scheme. <br>
9041
9042
9043
9044
9045 </div>
9046
9047
9048
9049
9050 <br>
9051
9052
9053
9054
9055 
9056     
9057     
9058     
9059     
9060      <p><span style="font-style: italic;">'bc-scheme'</span><br>
9061
9062
9063
9064
9065
9066      </p>
9067
9068
9069
9070
9071 
9072     
9073     
9074     
9075     
9076      <div style="margin-left: 40px;">The Bott
9077scheme modified by
9078Chlond (1994, Mon.
9079Wea. Rev., 122, 111-125). This is a conservative monotonous scheme with
9080very small numerical diffusion and therefore very good conservation of
9081scalar flow features. The scheme however, is computationally very
9082expensive both because it is expensive itself and because it does (so
9083far) not allow specific code optimizations (e.g. cache optimization).
9084Choice of this
9085scheme forces the Euler timestep scheme to be used for the scalar
9086quantities. For output of horizontally averaged
9087profiles of the resolved / total heat flux, <a href="chapter_4.2.html#data_output_pr">data_output_pr</a>
9088= <i>'w*pt*BC'</i> / <i>'wptBC' </i>should
9089be used, instead of the
9090standard profiles (<span style="font-style: italic;">'w*pt*'</span>
9091and <span style="font-style: italic;">'wpt'</span>)
9092because these are
9093too inaccurate with this scheme. However, for subdomain analysis (see <a href="#statistic_regions">statistic_regions</a>)
9094exactly the reverse holds: here <i>'w*pt*BC'</i> and <i>'wptBC'</i>
9095show very large errors and should not be used.<br>
9096
9097
9098
9099
9100 <br>
9101
9102
9103
9104
9105
9106This scheme is not allowed for non-cyclic lateral boundary conditions
9107(see <a href="#bc_lr">bc_lr</a>
9108and <a href="#bc_ns">bc_ns</a>).<br>
9109
9110
9111
9112
9113 <br>
9114
9115
9116
9117
9118
9119      </div>
9120
9121
9122
9123
9124 <span style="font-style: italic;">'ups-scheme'</span><br>
9125
9126
9127
9128
9129
9130     
9131     
9132     
9133     
9134      <p style="margin-left: 40px;">The upstream-spline-scheme
9135is used
9136(see Mahrer and Pielke,
91371978: Mon. Wea. Rev., 106, 818-830). In opposite to the Piascek
9138Williams scheme, this is characterized by much better numerical
9139features (less numerical diffusion, better preservation of flux
9140structures, e.g. vortices), but computationally it is much more
9141expensive. In
9142addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
9143= <span style="font-style: italic;">'</span><i>euler'</i>),
9144i.e. the
9145timestep accuracy is only first order. For this reason the advection of
9146momentum (see <a href="#momentum_advec">momentum_advec</a>)
9147should then also be carried out with the upstream-spline scheme,
9148because otherwise the momentum would
9149be subject to large numerical diffusion due to the upstream
9150scheme.&nbsp; </p>
9151
9152
9153
9154
9155 
9156     
9157     
9158     
9159     
9160      <p style="margin-left: 40px;">Since
9161the cubic splines used tend
9162to overshoot under
9163certain circumstances, this effect must be adjusted by suitable
9164filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
9165      <a href="#long_filter_factor">long_filter_factor</a>,
9166      <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>).
9167This is always neccesssary for runs with stable stratification,
9168even if this stratification appears only in parts of the model
9169domain.&nbsp; </p>
9170
9171
9172
9173
9174 
9175     
9176     
9177     
9178     
9179      <p style="margin-left: 40px;">With
9180stable stratification the
9181upstream-upline scheme also produces gravity waves with large
9182amplitude, which must be
9183suitably damped (see <a href="chapter_4.2.html#rayleigh_damping_factor">rayleigh_damping_factor</a>).<br>
9184
9185
9186
9187
9188
9189      </p>
9190
9191
9192
9193
9194 
9195     
9196     
9197     
9198     
9199      <p style="margin-left: 40px;"><span style="font-weight: bold;">Important: </span>The&nbsp;
9200upstream-spline scheme is not implemented for humidity and passive
9201scalars (see&nbsp;<a href="#humidity">humidity</a>
9202and <a href="#passive_scalar">passive_scalar</a>)
9203and requires the use of a 2d-domain-decomposition. The last conditions
9204severely restricts code optimization on several machines leading to
9205very long execution times! This scheme is also not allowed for
9206non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
9207and <a href="#bc_ns">bc_ns</a>).</p>
9208
9209
9210
9211
9212      <br>
9213
9214
9215
9216
9217A
9218differing advection scheme can be choosed for the subgrid-scale TKE
9219using parameter <a href="chapter_4.1.html#use_upstream_for_tke">use_upstream_for_tke</a>.</td>
9220
9221
9222
9223
9224
9225    </tr>
9226
9227
9228
9229
9230 <tr>
9231
9232
9233
9234
9235 <td style="vertical-align: top;">
9236     
9237     
9238     
9239     
9240      <p><a name="statistic_regions"></a><b>statistic_regions</b></p>
9241
9242
9243
9244
9245
9246      </td>
9247
9248
9249
9250
9251 <td style="vertical-align: top;">I</td>
9252
9253
9254
9255
9256
9257      <td style="vertical-align: top;"><i>0</i></td>
9258
9259
9260
9261
9262
9263      <td style="vertical-align: top;"> 
9264     
9265     
9266     
9267     
9268      <p>Number of
9269additional user-defined subdomains for which
9270statistical analysis
9271and corresponding output (profiles, time series) shall be
9272made.&nbsp; </p>
9273
9274
9275
9276
9277 
9278     
9279     
9280     
9281     
9282      <p>By default, vertical profiles and
9283other statistical quantities
9284are calculated as horizontal and/or volume average of the total model
9285domain. Beyond that, these calculations can also be carried out for
9286subdomains which can be defined using the field <a href="chapter_3.5.3.html">rmask </a>within the
9287user-defined software
9288(see <a href="chapter_3.5.3.html">chapter
92893.5.3</a>). The number of these subdomains is determined with the
9290parameter <b>statistic_regions</b>. Maximum 9 additional
9291subdomains
9292are allowed. The parameter <a href="chapter_4.3.html#region">region</a>
9293can be used to assigned names (identifier) to these subdomains which
9294are then used in the headers
9295of the output files and plots.</p>
9296
9297
9298
9299
9300     
9301     
9302     
9303     
9304      <p>If the default NetCDF
9305output format is selected (see parameter <a href="chapter_4.2.html#data_output_format">data_output_format</a>),
9306data for the total domain and all defined subdomains are output to the
9307same file(s) (<a href="chapter_3.4.html#DATA_1D_PR_NETCDF">DATA_1D_PR_NETCDF</a>,
9308      <a href="chapter_3.4.html#DATA_1D_TS_NETCDF">DATA_1D_TS_NETCDF</a>).
9309In case of <span style="font-weight: bold;">statistic_regions</span>
9310&gt; <span style="font-style: italic;">0</span>,
9311data on the file for the different domains can be distinguished by a
9312suffix which is appended to the quantity names. Suffix 0 means data for
9313the total domain, suffix 1 means data for subdomain 1, etc.</p>
9314
9315
9316
9317
9318     
9319     
9320     
9321     
9322      <p>In
9323case of <span style="font-weight: bold;">data_output_format</span>
9324= <span style="font-style: italic;">'profil'</span>,
9325individual local files for profiles (<a href="chapter_3.4.html#PLOT1D_DATA">PLOT1D_DATA</a>)&nbsp;are
9326created for each subdomain. The individual subdomain files differ by
9327their name (the
9328number of the respective subdomain is attached, e.g.
9329PLOT1D_DATA_1). In this case the name of the file with the data of
9330the total domain is PLOT1D_DATA_0. If no subdomains
9331are declared (<b>statistic_regions</b> = <i>0</i>),
9332the name
9333PLOT1D_DATA is used (this must be considered in the
9334respective file connection statements of the <span style="font-weight: bold;">mrun</span> configuration
9335file).</p>
9336
9337
9338
9339
9340 </td>
9341
9342
9343
9344
9345 </tr>
9346
9347
9348
9349
9350 <tr>
9351
9352
9353
9354
9355 <td style="vertical-align: top;"> 
9356     
9357     
9358     
9359     
9360      <p><a name="surface_heatflux"></a><b>surface_heatflux</b></p>
9361
9362
9363
9364
9365
9366      </td>
9367
9368
9369
9370
9371 <td style="vertical-align: top;">R</td>
9372
9373
9374
9375
9376
9377      <td style="vertical-align: top;"><span style="font-style: italic;">no prescribed<br>
9378
9379
9380
9381
9382
9383heatflux<br>
9384
9385
9386
9387
9388 </span></td>
9389
9390
9391
9392
9393 <td style="vertical-align: top;"> 
9394     
9395     
9396     
9397     
9398      <p>Kinematic sensible
9399heat flux at the bottom surface (in K m/s).&nbsp; </p>
9400
9401
9402
9403
9404 
9405     
9406     
9407     
9408     
9409      <p>If
9410a value is assigned to this parameter, the internal two-dimensional
9411surface heat flux field <span style="font-style: italic;">shf</span>
9412is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>&nbsp;as
9413bottom (horizontally homogeneous) boundary condition for the
9414temperature equation. This additionally requires that a Neumann
9415condition must be used for the potential temperature (see <a href="#bc_pt_b">bc_pt_b</a>),
9416because otherwise the resolved scale may contribute to
9417the surface flux so that a constant value cannot be guaranteed. Also,
9418changes of the
9419surface temperature (see <a href="#pt_surface_initial_change">pt_surface_initial_change</a>)
9420are not allowed. The parameter <a href="#random_heatflux">random_heatflux</a>
9421can be used to impose random perturbations on the (homogeneous) surface
9422heat
9423flux field <span style="font-style: italic;">shf</span>.&nbsp;</p>
9424
9425
9426
9427
9428
9429     
9430     
9431     
9432     
9433      <p>
9434In case of a non-flat <a href="#topography">topography</a>,&nbsp;the
9435internal two-dimensional&nbsp;surface heat
9436flux field <span style="font-style: italic;">shf</span>
9437is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>
9438at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
9439at the topography top face.&nbsp;The parameter<a href="#random_heatflux"> random_heatflux</a>
9440can be used to impose random perturbations on this combined surface
9441heat
9442flux field <span style="font-style: italic;">shf</span>.&nbsp;
9443      </p>
9444
9445
9446
9447
9448 
9449     
9450     
9451     
9452     
9453      <p>If no surface heat flux is assigned, <span style="font-style: italic;">shf</span> is calculated
9454at each timestep by u<sub>*</sub> * theta<sub>*</sub>
9455(of course only with <a href="#prandtl_layer">prandtl_layer</a>
9456switched on). Here, u<sub>*</sub>
9457and theta<sub>*</sub> are calculated from the Prandtl law
9458assuming
9459logarithmic wind and temperature
9460profiles between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_pt_b">bc_pt_b</a>)
9461must be used as bottom boundary condition for the potential temperature.</p>
9462
9463
9464
9465
9466     
9467     
9468     
9469     
9470      <p>See
9471also <a href="#top_heatflux">top_heatflux</a>.</p>
9472
9473
9474
9475
9476
9477      </td>
9478
9479
9480
9481
9482 </tr>
9483
9484
9485
9486
9487 <tr>
9488
9489
9490
9491
9492 <td style="vertical-align: top;"> 
9493     
9494     
9495     
9496     
9497      <p><a name="surface_pressure"></a><b>surface_pressure</b></p>
9498
9499
9500
9501
9502
9503      </td>
9504
9505
9506
9507
9508 <td style="vertical-align: top;">R</td>
9509
9510
9511
9512
9513
9514      <td style="vertical-align: top;"><i>1013.25</i></td>
9515
9516
9517
9518
9519
9520      <td style="vertical-align: top;"> 
9521     
9522     
9523     
9524     
9525      <p>Atmospheric
9526pressure at the surface (in hPa).&nbsp; </p>
9527
9528
9529
9530
9531
9532Starting from this surface value, the vertical pressure
9533profile is calculated once at the beginning of the run assuming a
9534neutrally stratified
9535atmosphere. This is needed for
9536converting between the liquid water potential temperature and the
9537potential temperature (see <a href="#cloud_physics">cloud_physics</a><span style="text-decoration: underline;"></span>).</td>
9538
9539
9540
9541
9542
9543    </tr>
9544
9545
9546
9547
9548 <tr>
9549
9550
9551
9552
9553 <td style="vertical-align: top;">
9554     
9555     
9556     
9557     
9558      <p><a name="surface_scalarflux"></a><b>surface_scalarflux</b></p>
9559
9560
9561
9562
9563
9564      </td>
9565
9566
9567
9568
9569 <td style="vertical-align: top;">R</td>
9570
9571
9572
9573
9574
9575      <td style="vertical-align: top;"><i>0.0</i></td>
9576
9577
9578
9579
9580
9581      <td style="vertical-align: top;"> 
9582     
9583     
9584     
9585     
9586      <p>Scalar flux at
9587the surface (in kg/(m<sup>2</sup> s)).&nbsp; </p>
9588
9589
9590
9591
9592
9593     
9594     
9595     
9596     
9597      <p>If a non-zero value is assigned to this parameter, the
9598respective scalar flux value is used
9599as bottom (horizontally homogeneous) boundary condition for the scalar
9600concentration equation.&nbsp;This additionally requires that a
9601Neumann
9602condition must be used for the scalar concentration&nbsp;(see <a href="#bc_s_b">bc_s_b</a>),
9603because otherwise the resolved scale may contribute to
9604the surface flux so that a constant value cannot be guaranteed. Also,
9605changes of the
9606surface scalar concentration (see <a href="#s_surface_initial_change">s_surface_initial_change</a>)
9607are not allowed. <br>
9608
9609
9610
9611
9612 </p>
9613
9614
9615
9616
9617 
9618     
9619     
9620     
9621     
9622      <p>If no surface scalar
9623flux is assigned (<b>surface_scalarflux</b>
9624= <i>0.0</i>),
9625it is calculated at each timestep by u<sub>*</sub> * s<sub>*</sub>
9626(of course only with Prandtl layer switched on). Here, s<sub>*</sub>
9627is calculated from the Prandtl law assuming a logarithmic scalar
9628concentration
9629profile between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_s_b">bc_s_b</a>)
9630must be used as bottom boundary condition for the scalar concentration.</p>
9631
9632
9633
9634
9635
9636      </td>
9637
9638
9639
9640
9641 </tr>
9642
9643
9644
9645
9646 <tr>
9647
9648
9649
9650
9651 <td style="vertical-align: top;"> 
9652     
9653     
9654     
9655     
9656      <p><a name="surface_waterflux"></a><b>surface_waterflux</b></p>
9657
9658
9659
9660
9661
9662      </td>
9663
9664
9665
9666
9667 <td style="vertical-align: top;">R</td>
9668
9669
9670
9671
9672
9673      <td style="vertical-align: top;"><i>0.0</i></td>
9674
9675
9676
9677
9678
9679      <td style="vertical-align: top;"> 
9680     
9681     
9682     
9683     
9684      <p>Kinematic
9685water flux near the surface (in m/s).&nbsp; </p>
9686
9687
9688
9689
9690 
9691     
9692     
9693     
9694     
9695      <p>If
9696a non-zero value is assigned to this parameter, the
9697respective water flux value is used
9698as bottom (horizontally homogeneous) boundary condition for the
9699humidity equation. This additionally requires that a Neumann
9700condition must be used for the specific humidity / total water content
9701(see <a href="#bc_q_b">bc_q_b</a>),
9702because otherwise the resolved scale may contribute to
9703the surface flux so that a constant value cannot be guaranteed. Also,
9704changes of the
9705surface humidity (see <a href="#q_surface_initial_change">q_surface_initial_change</a>)
9706are not allowed.<br>
9707
9708
9709
9710
9711 </p>
9712
9713
9714
9715
9716 
9717     
9718     
9719     
9720     
9721      <p>If no surface water
9722flux is assigned (<b>surface_waterflux</b>
9723= <i>0.0</i>),
9724it is calculated at each timestep by u<sub>*</sub> * q<sub>*</sub>
9725(of course only with Prandtl layer switched on). Here, q<sub>*</sub>
9726is calculated from the Prandtl law assuming a logarithmic temperature
9727profile between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_q_b">bc_q_b</a>)
9728must be used as the bottom boundary condition for the humidity.</p>
9729
9730
9731
9732
9733
9734      </td>
9735
9736
9737
9738
9739 </tr>
9740
9741
9742
9743
9744 <tr>
9745
9746
9747
9748
9749 <td style="vertical-align: top;"> 
9750     
9751     
9752     
9753     
9754      <p><a name="s_surface"></a><b>s_surface</b></p>
9755
9756
9757
9758
9759
9760      </td>
9761
9762
9763
9764
9765 <td style="vertical-align: top;">R</td>
9766
9767
9768
9769
9770
9771      <td style="vertical-align: top;"><i>0.0</i></td>
9772
9773
9774
9775
9776
9777      <td style="vertical-align: top;"> 
9778     
9779     
9780     
9781     
9782      <p>Surface value
9783of the passive scalar (in kg/m<sup>3</sup>).&nbsp;<br>
9784
9785
9786
9787
9788
9789      </p>
9790
9791
9792
9793
9794
9795This parameter assigns the value of the passive scalar s at
9796the surface (k=0)<b>.</b> Starting from this value, the
9797initial vertical scalar concentration profile is constructed with<a href="#s_vertical_gradient">
9798s_vertical_gradient</a> and <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.</td>
9799
9800
9801
9802
9803
9804    </tr>
9805
9806
9807
9808
9809 <tr>
9810
9811
9812
9813
9814 <td style="vertical-align: top;">
9815     
9816     
9817     
9818     
9819      <p><a name="s_surface_initial_change"></a><b>s_surface_initial</b>
9820      <br>
9821
9822
9823
9824
9825 <b>_change</b></p>
9826
9827
9828
9829
9830 </td>
9831
9832
9833
9834
9835 <td style="vertical-align: top;">R</td>
9836
9837
9838
9839
9840 <td style="vertical-align: top;"><i>0.0</i></td>
9841
9842
9843
9844
9845
9846      <td style="vertical-align: top;"> 
9847     
9848     
9849     
9850     
9851      <p>Change in
9852surface scalar concentration to be made at the
9853beginning of the 3d run (in kg/m<sup>3</sup>).&nbsp; </p>
9854
9855
9856
9857
9858
9859     
9860     
9861     
9862     
9863      <p>If <b>s_surface_initial_change</b><i>&nbsp;</i>is
9864set to a
9865non-zero
9866value, the near surface scalar flux is not allowed to be given
9867simultaneously (see <a href="#surface_scalarflux">surface_scalarflux</a>).</p>
9868
9869
9870
9871
9872
9873      </td>
9874
9875
9876
9877
9878 </tr>
9879
9880
9881
9882
9883 <tr>
9884
9885
9886
9887
9888 <td style="vertical-align: top;"> 
9889     
9890     
9891     
9892     
9893      <p><a name="s_vertical_gradient"></a><b>s_vertical_gradient</b></p>
9894
9895
9896
9897
9898
9899      </td>
9900
9901
9902
9903
9904 <td style="vertical-align: top;">R (10)</td>
9905
9906
9907
9908
9909
9910      <td style="vertical-align: top;"><i>10 * 0</i><i>.0</i></td>
9911
9912
9913
9914
9915
9916      <td style="vertical-align: top;"> 
9917     
9918     
9919     
9920     
9921      <p>Scalar
9922concentration gradient(s) of the initial scalar
9923concentration profile (in kg/m<sup>3 </sup>/
9924100 m).&nbsp; </p>
9925
9926
9927
9928
9929 
9930     
9931     
9932     
9933     
9934      <p>The scalar gradient holds
9935starting from the height level
9936defined by <a href="#s_vertical_gradient_level">s_vertical_gradient_level
9937      </a>(precisely: for all uv levels k, where zu(k) &gt;
9938s_vertical_gradient_level, s_init(k) is set: s_init(k) = s_init(k-1) +
9939dzu(k) * <b>s_vertical_gradient</b>) up to the top
9940boundary or up to
9941the next height level defined by <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
9942A total of 10 different gradients for 11 height intervals (10 intervals
9943if <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>(1)
9944= <i>0.0</i>) can be assigned. The surface scalar value is
9945assigned
9946via <a href="#s_surface">s_surface</a>.<br>
9947
9948
9949
9950
9951 </p>
9952
9953
9954
9955
9956
9957     
9958     
9959     
9960     
9961      <p>Example:&nbsp; </p>
9962
9963
9964
9965
9966 
9967     
9968     
9969     
9970     
9971      <ul>
9972
9973
9974
9975
9976 
9977       
9978       
9979       
9980       
9981        <p><b>s_vertical_gradient</b>
9982= <i>0.1</i>, <i>0.05</i>,&nbsp; <br>
9983
9984
9985
9986
9987
9988        <b>s_vertical_gradient_level</b> = <i>500.0</i>,
9989        <i>1000.0</i>,</p>
9990
9991
9992
9993
9994 
9995     
9996     
9997     
9998     
9999      </ul>
10000
10001
10002
10003
10004 
10005     
10006     
10007     
10008     
10009      <p>That
10010defines the scalar concentration to be constant with
10011height up to z = 500.0 m with a value given by <a href="#s_surface">s_surface</a>.
10012For 500.0 m &lt; z &lt;= 1000.0 m the scalar gradient is 0.1
10013kg/m<sup>3 </sup>/ 100 m and for z &gt; 1000.0 m up to
10014the top
10015boundary it is 0.05 kg/m<sup>3 </sup>/ 100 m (it is
10016assumed that the
10017assigned height levels
10018correspond with uv
10019levels).</p>
10020
10021
10022
10023
10024 </td>
10025
10026
10027
10028
10029 </tr>
10030
10031
10032
10033
10034 <tr>
10035
10036
10037
10038
10039 <td style="vertical-align: top;"> 
10040     
10041     
10042     
10043     
10044      <p><a name="s_vertical_gradient_level"></a><b>s_vertical_gradient_</b>
10045      <br>
10046
10047
10048
10049
10050 <b>level</b></p>
10051
10052
10053
10054
10055 </td>
10056
10057
10058
10059
10060 <td style="vertical-align: top;">R (10)</td>
10061
10062
10063
10064
10065 <td style="vertical-align: top;"> 
10066     
10067     
10068     
10069     
10070      <p><i>10 *</i>
10071      <i>0.0</i></p>
10072
10073
10074
10075
10076 </td>
10077
10078
10079
10080
10081 <td style="vertical-align: top;"> 
10082     
10083     
10084     
10085     
10086      <p>Height level from
10087which on the scalar gradient defined by <a href="#s_vertical_gradient">s_vertical_gradient</a>
10088is effective (in m).&nbsp; </p>
10089
10090
10091
10092
10093 
10094     
10095     
10096     
10097     
10098      <p>The height levels
10099are to be assigned in ascending order. The
10100default values result in a scalar concentration constant with height
10101regardless of the values of <a href="#s_vertical_gradient">s_vertical_gradient</a>
10102(unless the top boundary of the model is higher than 100000.0 m). For
10103the
10104piecewise construction of scalar concentration profiles see <a href="#s_vertical_gradient">s_vertical_gradient</a>.</p>
10105
10106
10107
10108
10109
10110      </td>
10111
10112
10113
10114
10115 </tr>
10116
10117
10118
10119
10120 <tr>
10121
10122
10123
10124
10125 <td style="vertical-align: top;"> 
10126     
10127     
10128     
10129     
10130      <p><a name="timestep_scheme"></a><b>timestep_scheme</b></p>
10131
10132
10133
10134
10135
10136      </td>
10137
10138
10139
10140
10141 <td style="vertical-align: top;">C * 20</td>
10142
10143
10144
10145
10146
10147      <td style="vertical-align: top;"> 
10148     
10149     
10150     
10151     
10152      <p><i>'runge</i><br>
10153
10154
10155
10156
10157
10158      <i>kutta-3'</i></p>
10159
10160
10161
10162
10163 </td>
10164
10165
10166
10167
10168 <td style="vertical-align: top;"> 
10169     
10170     
10171     
10172     
10173      <p>Time step scheme to
10174be used for the integration of the prognostic
10175variables.&nbsp; </p>
10176
10177
10178
10179
10180 
10181     
10182     
10183     
10184     
10185      <p>The user can choose between
10186the following schemes:<br>
10187
10188
10189
10190
10191 </p>
10192
10193
10194
10195
10196 
10197     
10198     
10199     
10200     
10201      <p><span style="font-style: italic;">'runge-kutta-3'</span><br>
10202
10203
10204
10205
10206
10207      </p>
10208
10209
10210
10211
10212 
10213     
10214     
10215     
10216     
10217      <div style="margin-left: 40px;">Third order
10218Runge-Kutta scheme.<br>
10219
10220
10221
10222
10223
10224This scheme requires the use of <a href="#momentum_advec">momentum_advec</a>
10225= <a href="#scalar_advec">scalar_advec</a>
10226= '<i>pw-scheme'</i>. Please refer to the&nbsp;<a href="../tec/numerik.heiko/zeitschrittverfahren.pdf">documentation
10227on PALM's time integration schemes&nbsp;(28p., in German)</a>
10228fur further details.<br>
10229
10230
10231
10232
10233 </div>
10234
10235
10236
10237
10238 
10239     
10240     
10241     
10242     
10243      <p><span style="font-style: italic;">'runge-kutta-2'</span><br>
10244
10245
10246
10247
10248
10249      </p>
10250
10251
10252
10253
10254 
10255     
10256     
10257     
10258     
10259      <div style="margin-left: 40px;">Second order
10260Runge-Kutta scheme.<br>
10261
10262
10263
10264
10265
10266For special features see <b>timestep_scheme</b> = '<i>runge-kutta-3'</i>.<br>
10267
10268
10269
10270
10271
10272      </div>
10273
10274
10275
10276
10277 <br>
10278
10279
10280
10281
10282 <span style="font-style: italic;"><span style="font-style: italic;">'leapfrog'</span><br>
10283
10284
10285
10286
10287
10288      <br>
10289
10290
10291
10292
10293 </span> 
10294     
10295     
10296     
10297     
10298      <div style="margin-left: 40px;">Second
10299order leapfrog scheme.<br>
10300
10301
10302
10303
10304
10305Although this scheme requires a constant timestep (because it is
10306centered in time),&nbsp; is even applied in case of changes in
10307timestep. Therefore, only small
10308changes of the timestep are allowed (see <a href="#dt">dt</a>).
10309However, an Euler timestep is always used as the first timestep of an
10310initiali run. When using the Bott-Chlond scheme for scalar advection
10311(see <a href="#scalar_advec">scalar_advec</a>),
10312the prognostic equation for potential temperature will be calculated
10313with the Euler scheme, although the leapfrog scheme is switched
10314on.&nbsp; <br>
10315
10316
10317
10318
10319
10320The leapfrog scheme must not be used together with the upstream-spline
10321scheme for calculating the advection (see <a href="#scalar_advec">scalar_advec</a>
10322= '<i>ups-scheme'</i> and <a href="#momentum_advec">momentum_advec</a>
10323= '<i>ups-scheme'</i>).<br>
10324
10325
10326
10327
10328 </div>
10329
10330
10331
10332
10333 <br>
10334
10335
10336
10337
10338
10339      <span style="font-style: italic;">'</span><span style="font-style: italic;"><span style="font-style: italic;">leapfrog+euler'</span><br>
10340
10341
10342
10343
10344
10345      <br>
10346
10347
10348
10349
10350 </span> 
10351     
10352     
10353     
10354     
10355      <div style="margin-left: 40px;">The
10356leapfrog scheme is used, but
10357after each change of a timestep an Euler timestep is carried out.
10358Although this method is theoretically correct (because the pure
10359leapfrog method does not allow timestep changes), the divergence of the
10360velocity field (after applying the pressure solver) may be
10361significantly larger than with <span style="font-style: italic;">'leapfrog'</span>.<br>
10362
10363
10364
10365
10366
10367      </div>
10368
10369
10370
10371
10372 <br>
10373
10374
10375
10376
10377 <span style="font-style: italic;">'euler'</span><br>
10378
10379
10380
10381
10382
10383      <br>
10384
10385
10386
10387
10388 
10389     
10390     
10391     
10392     
10393      <div style="margin-left: 40px;">First order
10394Euler scheme.&nbsp; <br>
10395
10396
10397
10398
10399
10400The Euler scheme must be used when treating the advection terms with
10401the upstream-spline scheme (see <a href="#scalar_advec">scalar_advec</a>
10402= <span style="font-style: italic;">'ups-scheme'</span>
10403and <a href="#momentum_advec">momentum_advec</a>
10404= <span style="font-style: italic;">'ups-scheme'</span>).</div>
10405
10406
10407
10408
10409
10410      <br>
10411
10412
10413
10414
10415      <br>
10416
10417
10418
10419
10420A differing timestep scheme can be choosed for the
10421subgrid-scale TKE using parameter <a href="#use_upstream_for_tke">use_upstream_for_tke</a>.<br>
10422
10423
10424
10425
10426
10427      </td>
10428
10429
10430
10431
10432 </tr>
10433
10434
10435
10436
10437 <tr>
10438
10439
10440
10441
10442 <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>
10443
10444
10445
10446
10447
10448      <td style="vertical-align: top;">C * 40</td>
10449
10450
10451
10452
10453 <td style="vertical-align: top;"><span style="font-style: italic;">'flat'</span></td>
10454
10455
10456
10457
10458 <td>
10459     
10460     
10461     
10462     
10463      <p>Topography mode.&nbsp; </p>
10464
10465
10466
10467
10468 
10469     
10470     
10471     
10472     
10473      <p>The user can
10474choose between the following modes:<br>
10475
10476
10477
10478
10479 </p>
10480
10481
10482
10483
10484 
10485     
10486     
10487     
10488     
10489      <p><span style="font-style: italic;">'flat'</span><br>
10490
10491
10492
10493
10494 </p>
10495
10496
10497
10498
10499
10500     
10501     
10502     
10503     
10504      <div style="margin-left: 40px;">Flat surface.</div>
10505
10506
10507