source: palm/trunk/DOC/app/chapter_4.1.html @ 108

Last change on this file since 108 was 108, checked in by letzel, 15 years ago
  • Improved coupler: evaporation - salinity-flux coupling for humidity = .T.,

avoid MPI hangs when coupled runs terminate, add DOC/app/chapter_3.8;

  • Optional calculation of km and kh from initial TKE e_init;
  • Default initialization of km,kh = 0.00001 for ocean = .T.;
  • Allow data_output_pr= q, wq, w"q", w*q* for humidity = .T.;
  • Bugfix: Rayleigh damping for ocean fixed.
  • Property svn:keywords set to Id
File size: 180.0 KB
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18  <title>PALM chapter 4.1</title>
19</head>
20
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22<body>
23
24
25
26<h3><a name="chapter4.1"></a>4.1
27Initialization parameters</h3>
28
29
30
31
32<br>
33
34
35
36<table style="text-align: left; width: 100%;" border="1" cellpadding="2" cellspacing="2">
37
38
39
40 <tbody>
41
42
43
44
45    <tr>
46
47
48
49 <td style="vertical-align: top;"><font size="4"><b>Parameter name</b></font></td>
50
51
52
53
54      <td style="vertical-align: top;"><font size="4"><b>Type</b></font></td>
55
56
57
58
59      <td style="vertical-align: top;"> 
60     
61     
62     
63      <p><b><font size="4">Default</font></b> <br>
64
65
66
67 <b><font size="4">value</font></b></p>
68
69
70
71 </td>
72
73
74
75
76      <td style="vertical-align: top;"><font size="4"><b>Explanation</b></font></td>
77
78
79
80
81    </tr>
82
83
84
85 <tr>
86
87
88
89 <td style="vertical-align: top;">
90     
91     
92     
93      <p><a name="adjust_mixing_length"></a><b>adjust_mixing_length</b></p>
94
95
96
97
98      </td>
99
100
101
102 <td style="vertical-align: top;">L</td>
103
104
105
106
107      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
108
109
110
111 <td style="vertical-align: top;"> 
112     
113     
114     
115      <p style="font-style: normal;">Near-surface adjustment of the
116mixing length to the Prandtl-layer law.&nbsp; </p>
117
118
119
120 
121     
122     
123     
124      <p>Usually
125the mixing length in LES models l<sub>LES</sub>
126depends (as in PALM) on the grid size and is possibly restricted
127further in case of stable stratification and near the lower wall (see
128parameter <a href="#wall_adjustment">wall_adjustment</a>).
129With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span>
130the Prandtl' mixing length l<sub>PR</sub> = kappa * z/phi
131is calculated
132and the mixing length actually used in the model is set l = MIN (l<sub>LES</sub>,
133l<sub>PR</sub>). This usually gives a decrease of the
134mixing length at
135the bottom boundary and considers the fact that eddy sizes
136decrease in the vicinity of the wall.&nbsp; </p>
137
138
139
140 
141     
142     
143     
144      <p style="font-style: normal;"><b>Warning:</b> So
145far, there is
146no good experience with <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> !&nbsp; </p>
147
148
149
150
151     
152     
153     
154      <p>With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> and the
155Prandtl-layer being
156switched on (see <a href="#prandtl_layer">prandtl_layer</a>)
157      <span style="font-style: italic;">'(u*)** 2+neumann'</span>
158should always be set as the lower boundary condition for the TKE (see <a href="#bc_e_b">bc_e_b</a>),
159otherwise the near-surface value of the TKE is not in agreement with
160the Prandtl-layer law (Prandtl-layer law and Prandtl-Kolmogorov-Ansatz
161should provide the same value for K<sub>m</sub>). A warning
162is given,
163if this is not the case.</p>
164
165
166
167 </td>
168
169
170
171 </tr>
172
173
174
175 <tr>
176
177
178
179
180      <td style="vertical-align: top;"> 
181     
182     
183     
184      <p><a name="alpha_surface"></a><b>alpha_surface</b></p>
185
186
187
188
189      </td>
190
191
192
193 <td style="vertical-align: top;">R<br>
194
195
196
197 </td>
198
199
200
201
202      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
203
204
205
206 </td>
207
208
209
210
211      <td style="vertical-align: top;"> 
212     
213     
214     
215      <p style="font-style: normal;">Inclination of the model domain
216with respect to the horizontal (in degrees).&nbsp; </p>
217
218
219
220 
221     
222     
223     
224      <p style="font-style: normal;">By means of <b>alpha_surface</b>
225the model domain can be inclined in x-direction with respect to the
226horizontal. In this way flows over inclined surfaces (e.g. drainage
227flows, gravity flows) can be simulated. In case of <b>alpha_surface
228      </b>/= <span style="font-style: italic;">0</span>
229the buoyancy term
230appears both in
231the equation of motion of the u-component and of the w-component.<br>
232
233
234
235
236      </p>
237
238
239
240 
241     
242     
243     
244      <p style="font-style: normal;">An inclination
245is only possible in
246case of cyclic horizontal boundary conditions along x AND y (see <a href="#bc_lr">bc_lr</a>
247and <a href="#bc_ns">bc_ns</a>) and <a href="#topography">topography</a> = <span style="font-style: italic;">'flat'</span>. </p>
248
249
250
251
252     
253     
254     
255      <p>Runs with inclined surface still require additional
256user-defined code as well as modifications to the default code. Please
257ask the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/PALM_group.html#0">PALM
258developer&nbsp; group</a>.</p>
259
260
261
262 </td>
263
264
265
266 </tr>
267
268
269
270
271    <tr>
272
273
274
275 <td style="vertical-align: top;"> 
276     
277     
278     
279      <p><a name="bc_e_b"></a><b>bc_e_b</b></p>
280
281
282
283 </td>
284
285
286
287
288      <td style="vertical-align: top;">C * 20</td>
289
290
291
292 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
293
294
295
296
297      <td style="vertical-align: top;"> 
298     
299     
300     
301      <p style="font-style: normal;">Bottom boundary condition of the
302TKE.&nbsp; </p>
303
304
305
306 
307     
308     
309     
310      <p><b>bc_e_b</b> may be
311set to&nbsp;<span style="font-style: italic;">'neumann'</span>
312or <span style="font-style: italic;">'(u*) ** 2+neumann'</span>.
313      <b>bc_e_b</b>
314= <span style="font-style: italic;">'neumann'</span>
315yields to
316e(k=0)=e(k=1) (Neumann boundary condition), where e(k=1) is calculated
317via the prognostic TKE equation. Choice of <span style="font-style: italic;">'(u*)**2+neumann'</span>
318also yields to
319e(k=0)=e(k=1), but the TKE at the Prandtl-layer top (k=1) is calculated
320diagnostically by e(k=1)=(us/0.1)**2. However, this is only allowed if
321a Prandtl-layer is used (<a href="#prandtl_layer">prandtl_layer</a>).
322If this is not the case, a warning is given and <b>bc_e_b</b>
323is reset
324to <span style="font-style: italic;">'neumann'</span>.&nbsp;
325      </p>
326
327
328
329 
330     
331     
332     
333      <p style="font-style: normal;">At the top
334boundary a Neumann
335boundary condition is generally used: (e(nz+1) = e(nz)).</p>
336
337
338
339 </td>
340
341
342
343
344    </tr>
345
346
347
348 <tr>
349
350
351
352 <td style="vertical-align: top;">
353     
354     
355     
356      <p><a name="bc_lr"></a><b>bc_lr</b></p>
357
358
359
360
361      </td>
362
363
364
365 <td style="vertical-align: top;">C * 20</td>
366
367
368
369
370      <td style="vertical-align: top;"><span style="font-style: italic;">'cyclic'</span></td>
371
372
373
374
375      <td style="vertical-align: top;">Boundary
376condition along x (for all quantities).<br>
377
378
379
380 <br>
381
382
383
384
385By default, a cyclic boundary condition is used along x.<br>
386
387
388
389 <br>
390
391
392
393
394      <span style="font-weight: bold;">bc_lr</span> may
395also be
396assigned the values <span style="font-style: italic;">'dirichlet/radiation'</span>
397(inflow from left, outflow to the right) or <span style="font-style: italic;">'radiation/dirichlet'</span>
398(inflow from
399right, outflow to the left). This requires the multi-grid method to be
400used 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>)
401and it also requires cyclic boundary conditions along y (see&nbsp;<a href="#bc_ns">bc_ns</a>).<br>
402
403
404
405 <br>
406
407
408
409
410In case of these non-cyclic lateral boundaries, a Dirichlet condition
411is used at the inflow for all quantities (initial vertical profiles -
412see <a href="#initializing_actions">initializing_actions</a>
413- are fixed during the run) except u, to which a Neumann (zero
414gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
415gradient) condition is used for the scalars. For perturbation
416pressure Neumann (zero gradient) conditions are assumed both at the
417inflow and at the outflow.<br>
418
419
420
421 <br>
422
423
424
425
426When using non-cyclic lateral boundaries, a filter is applied to the
427velocity field in the vicinity of the outflow in order to suppress any
428reflections of outgoing disturbances (see <a href="#km_damp_max">km_damp_max</a>
429and <a href="#outflow_damping_width">outflow_damping_width</a>).<br>
430
431
432
433
434      <br>
435
436
437
438
439In order to maintain a turbulent state of the flow, it may be
440neccessary to continuously impose perturbations on the horizontal
441velocity field in the vicinity of the inflow throughout the whole run.
442This 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>.
443The horizontal range to which these perturbations are applied is
444controlled by the parameters <a href="#inflow_disturbance_begin">inflow_disturbance_begin</a>
445and <a href="#inflow_disturbance_end">inflow_disturbance_end</a>.
446The 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>,
447      <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_level_t</a>,
448and <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_amplitude</a>.
449The 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>
450
451
452
453
454      <br>
455
456
457
458
459In 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
460at_all_substeps</a> = .T. should be used.<br>
461
462
463
464 <br>
465
466
467
468 <span style="font-weight: bold;">Note:</span><br>
469
470
471
472
473Using non-cyclic lateral boundaries requires very sensitive adjustments
474of the inflow (vertical profiles) and the bottom boundary conditions,
475e.g. a surface heating should not be applied near the inflow boundary
476because this may significantly disturb the inflow. Please check the
477model results very carefully.</td>
478
479
480
481 </tr>
482
483
484
485 <tr>
486
487
488
489 <td style="vertical-align: top;"> 
490     
491     
492     
493      <p><a name="bc_ns"></a><b>bc_ns</b></p>
494
495
496
497
498      </td>
499
500
501
502 <td style="vertical-align: top;">C * 20</td>
503
504
505
506
507      <td style="vertical-align: top;"><span style="font-style: italic;">'cyclic'</span></td>
508
509
510
511
512      <td style="vertical-align: top;">Boundary
513condition along y (for all quantities).<br>
514
515
516
517 <br>
518
519
520
521
522By default, a cyclic boundary condition is used along y.<br>
523
524
525
526 <br>
527
528
529
530
531      <span style="font-weight: bold;">bc_ns</span> may
532also be
533assigned the values <span style="font-style: italic;">'dirichlet/radiation'</span>
534(inflow from rear ("north"), outflow to the front ("south")) or <span style="font-style: italic;">'radiation/dirichlet'</span>
535(inflow from front ("south"), outflow to the rear ("north")). This
536requires the multi-grid
537method to be used for solving the Poisson equation for perturbation
538pressure (see <a href="chapter_4.2.html#psolver">psolver</a>)
539and it also requires cyclic boundary conditions along x (see<br>
540
541
542
543 <a href="#bc_lr">bc_lr</a>).<br>
544
545
546
547 <br>
548
549
550
551
552In case of these non-cyclic lateral boundaries, a Dirichlet condition
553is used at the inflow for all quantities (initial vertical profiles -
554see <a href="chapter_4.1.html#initializing_actions">initializing_actions</a>
555- are fixed during the run) except u, to which a Neumann (zero
556gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
557gradient) condition is used for the scalars. For perturbation
558pressure Neumann (zero gradient) conditions are assumed both at the
559inflow and at the outflow.<br>
560
561
562
563 <br>
564
565
566
567
568For further details regarding non-cyclic lateral boundary conditions
569see <a href="#bc_lr">bc_lr</a>.</td>
570
571
572
573 </tr>
574
575
576
577
578    <tr>
579
580
581
582 <td style="vertical-align: top;"> 
583     
584     
585     
586      <p><a name="bc_p_b"></a><b>bc_p_b</b></p>
587
588
589
590 </td>
591
592
593
594
595      <td style="vertical-align: top;">C * 20</td>
596
597
598
599 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
600
601
602
603
604      <td style="vertical-align: top;"> 
605     
606     
607     
608      <p style="font-style: normal;">Bottom boundary condition of the
609perturbation pressure.&nbsp; </p>
610
611
612
613 
614     
615     
616     
617      <p>Allowed values
618are <span style="font-style: italic;">'dirichlet'</span>,
619      <span style="font-style: italic;">'neumann'</span>
620and <span style="font-style: italic;">'neumann+inhomo'</span>.&nbsp;
621      <span style="font-style: italic;">'dirichlet'</span>
622sets
623p(k=0)=0.0,&nbsp; <span style="font-style: italic;">'neumann'</span>
624sets p(k=0)=p(k=1). <span style="font-style: italic;">'neumann+inhomo'</span>
625corresponds to an extended Neumann boundary condition where heat flux
626or temperature inhomogeneities near the
627surface (pt(k=1))&nbsp; are additionally regarded (see Shen and
628LeClerc
629(1995, Q.J.R. Meteorol. Soc.,
6301209)). This condition is only permitted with the Prandtl-layer
631switched on (<a href="#prandtl_layer">prandtl_layer</a>),
632otherwise the run is terminated.&nbsp; </p>
633
634
635
636 
637     
638     
639     
640      <p>Since
641at the bottom boundary of the model the vertical
642velocity
643disappears (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>)
644dp/dz = 0 should
645be used, which leaves the vertical component w unchanged when the
646pressure solver is applied. Simultaneous use of the Neumann boundary
647conditions both at the bottom and at the top boundary (<a href="#bc_p_t">bc_p_t</a>)
648usually yields no consistent solution for the perturbation pressure and
649should be avoided.</p>
650
651
652
653 </td>
654
655
656
657 </tr>
658
659
660
661 <tr>
662
663
664
665 <td style="vertical-align: top;"> 
666     
667     
668     
669      <p><a name="bc_p_t"></a><b>bc_p_t</b></p>
670
671
672
673
674      </td>
675
676
677
678 <td style="vertical-align: top;">C * 20</td>
679
680
681
682
683      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
684
685
686
687
688      <td style="vertical-align: top;"> 
689     
690     
691     
692      <p style="font-style: normal;">Top boundary condition of the
693perturbation pressure.&nbsp; </p>
694
695
696
697 
698     
699     
700     
701      <p style="font-style: normal;">Allowed values are <span style="font-style: italic;">'dirichlet'</span>
702(p(k=nz+1)= 0.0) or <span style="font-style: italic;">'neumann'</span>
703(p(k=nz+1)=p(k=nz)).&nbsp; </p>
704
705
706
707 
708     
709     
710     
711      <p>Simultaneous use
712of Neumann boundary conditions both at the
713top and bottom boundary (<a href="#bc_p_b">bc_p_b</a>)
714usually yields no consistent solution for the perturbation pressure and
715should be avoided. Since at the bottom boundary the Neumann
716condition&nbsp; is a good choice (see <a href="#bc_p_b">bc_p_b</a>),
717a Dirichlet condition should be set at the top boundary.</p>
718
719
720
721 </td>
722
723
724
725
726    </tr>
727
728
729
730 <tr>
731
732
733
734 <td style="vertical-align: top;">
735     
736     
737     
738      <p><a name="bc_pt_b"></a><b>bc_pt_b</b></p>
739
740
741
742
743      </td>
744
745
746
747 <td style="vertical-align: top;">C*20</td>
748
749
750
751
752      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
753
754
755
756
757      <td style="vertical-align: top;"> 
758     
759     
760     
761      <p style="font-style: normal;">Bottom boundary condition of the
762potential temperature.&nbsp; </p>
763
764
765
766 
767     
768     
769     
770      <p>Allowed values
771are <span style="font-style: italic;">'dirichlet'</span>
772(pt(k=0) = const. = <a href="#pt_surface">pt_surface</a>
773+ <a href="#pt_surface_initial_change">pt_surface_initial_change</a>;
774the user may change this value during the run using user-defined code)
775and <span style="font-style: italic;">'neumann'</span>
776(pt(k=0)=pt(k=1)).&nbsp; <br>
777
778
779
780
781When a constant surface sensible heat flux is used (<a href="#surface_heatflux">surface_heatflux</a>), <b>bc_pt_b</b>
782= <span style="font-style: italic;">'neumann'</span>
783must be used, because otherwise the resolved scale may contribute to
784the surface flux so that a constant value cannot be guaranteed.</p>
785
786
787
788     
789     
790     
791      <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>
792
793
794
795
796      </td>
797
798
799
800 </tr>
801
802
803
804 <tr>
805
806
807
808 <td style="vertical-align: top;"> 
809     
810     
811     
812      <p><a name="pc_pt_t"></a><b>bc_pt_t</b></p>
813
814
815
816
817      </td>
818
819
820
821 <td style="vertical-align: top;">C * 20</td>
822
823
824
825
826      <td style="vertical-align: top;"><span style="font-style: italic;">'initial_ gradient'</span></td>
827
828
829
830
831      <td style="vertical-align: top;"> 
832     
833     
834     
835      <p style="font-style: normal;">Top boundary condition of the
836potential temperature.&nbsp; </p>
837
838
839
840 
841     
842     
843     
844      <p>Allowed are the
845values <span style="font-style: italic;">'dirichlet' </span>(pt(k=nz+1)
846does not change during the run), <span style="font-style: italic;">'neumann'</span>
847(pt(k=nz+1)=pt(k=nz)), and <span style="font-style: italic;">'initial_gradient'</span>.
848With the 'initial_gradient'-condition the value of the temperature
849gradient at the top is
850calculated from the initial
851temperature profile (see <a href="#pt_surface">pt_surface</a>,
852      <a href="#pt_vertical_gradient">pt_vertical_gradient</a>)
853by bc_pt_t_val = (pt_init(k=nz+1) -
854pt_init(k=nz)) / dzu(nz+1).<br>
855
856
857
858
859Using this value (assumed constant during the
860run) the temperature boundary values are calculated as&nbsp; </p>
861
862
863
864
865     
866     
867     
868      <ul>
869
870
871
872 
873       
874       
875       
876        <p style="font-style: normal;">pt(k=nz+1) =
877pt(k=nz) +
878bc_pt_t_val * dzu(nz+1)</p>
879
880
881
882 
883     
884     
885     
886      </ul>
887
888
889
890 
891     
892     
893     
894      <p style="font-style: normal;">(up to k=nz the prognostic
895equation for the temperature is solved).<br>
896
897
898
899
900When a constant sensible heat flux is used at the top boundary (<a href="chapter_4.1.html#top_heatflux">top_heatflux</a>),
901      <b>bc_pt_t</b> = <span style="font-style: italic;">'neumann'</span>
902must be used, because otherwise the resolved scale may contribute to
903the top flux so that a constant value cannot be guaranteed.</p>
904
905
906
907 </td>
908
909
910
911
912    </tr>
913
914
915
916 <tr>
917
918
919
920 <td style="vertical-align: top;">
921     
922     
923     
924      <p><a name="bc_q_b"></a><b>bc_q_b</b></p>
925
926
927
928
929      </td>
930
931
932
933 <td style="vertical-align: top;">C * 20</td>
934
935
936
937
938      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
939
940
941
942
943      <td style="vertical-align: top;"> 
944     
945     
946     
947      <p style="font-style: normal;">Bottom boundary condition of the
948specific humidity / total water content.&nbsp; </p>
949
950
951
952 
953     
954     
955     
956      <p>Allowed
957values are <span style="font-style: italic;">'dirichlet'</span>
958(q(k=0) = const. = <a href="#q_surface">q_surface</a>
959+ <a href="#q_surface_initial_change">q_surface_initial_change</a>;
960the user may change this value during the run using user-defined code)
961and <span style="font-style: italic;">'neumann'</span>
962(q(k=0)=q(k=1)).&nbsp; <br>
963
964
965
966
967When a constant surface latent heat flux is used (<a href="#surface_waterflux">surface_waterflux</a>), <b>bc_q_b</b>
968= <span style="font-style: italic;">'neumann'</span>
969must be used, because otherwise the resolved scale may contribute to
970the surface flux so that a constant value cannot be guaranteed.</p>
971
972
973
974
975      </td>
976
977
978
979 </tr>
980
981
982
983 <tr>
984
985
986
987 <td style="vertical-align: top;"> 
988     
989     
990     
991      <p><a name="bc_q_t"></a><b>bc_q_t</b></p>
992
993
994
995
996      </td>
997
998
999
1000 <td style="vertical-align: top;"><span style="font-style: italic;">C
1001* 20</span></td>
1002
1003
1004
1005 <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1006
1007
1008
1009
1010      <td style="vertical-align: top;"> 
1011     
1012     
1013     
1014      <p style="font-style: normal;">Top boundary condition of the
1015specific humidity / total water content.&nbsp; </p>
1016
1017
1018
1019 
1020     
1021     
1022     
1023      <p>Allowed
1024are the values <span style="font-style: italic;">'dirichlet'</span>
1025(q(k=nz) and q(k=nz+1) do
1026not change during the run) and <span style="font-style: italic;">'neumann'</span>.
1027With the Neumann boundary
1028condition the value of the humidity gradient at the top is calculated
1029from the
1030initial humidity profile (see <a href="#q_surface">q_surface</a>,
1031      <a href="#q_vertical_gradient">q_vertical_gradient</a>)
1032by: bc_q_t_val = ( q_init(k=nz) - q_init(k=nz-1)) / dzu(nz).<br>
1033
1034
1035
1036
1037Using this value (assumed constant during the run) the humidity
1038boundary values
1039are calculated as&nbsp; </p>
1040
1041
1042
1043 
1044     
1045     
1046     
1047      <ul>
1048
1049
1050
1051 
1052       
1053       
1054       
1055        <p style="font-style: normal;">q(k=nz+1) =q(k=nz) +
1056bc_q_t_val * dzu(nz+1)</p>
1057
1058
1059
1060 
1061     
1062     
1063     
1064      </ul>
1065
1066
1067
1068 
1069     
1070     
1071     
1072      <p style="font-style: normal;">(up tp k=nz the prognostic
1073equation for q is solved). </p>
1074
1075
1076
1077 </td>
1078
1079
1080
1081 </tr>
1082
1083
1084
1085 <tr>
1086
1087
1088
1089
1090      <td style="vertical-align: top;"> 
1091     
1092     
1093     
1094      <p><a name="bc_s_b"></a><b>bc_s_b</b></p>
1095
1096
1097
1098 </td>
1099
1100
1101
1102
1103      <td style="vertical-align: top;">C * 20</td>
1104
1105
1106
1107 <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1108
1109
1110
1111
1112      <td style="vertical-align: top;"> 
1113     
1114     
1115     
1116      <p style="font-style: normal;">Bottom boundary condition of the
1117scalar concentration.&nbsp; </p>
1118
1119
1120
1121 
1122     
1123     
1124     
1125      <p>Allowed values
1126are <span style="font-style: italic;">'dirichlet'</span>
1127(s(k=0) = const. = <a href="#s_surface">s_surface</a>
1128+ <a href="#s_surface_initial_change">s_surface_initial_change</a>;
1129the user may change this value during the run using user-defined code)
1130and <span style="font-style: italic;">'neumann'</span>
1131(s(k=0) =
1132s(k=1)).&nbsp; <br>
1133
1134
1135
1136
1137When a constant surface concentration flux is used (<a href="#surface_scalarflux">surface_scalarflux</a>), <b>bc_s_b</b>
1138= <span style="font-style: italic;">'neumann'</span>
1139must be used, because otherwise the resolved scale may contribute to
1140the surface flux so that a constant value cannot be guaranteed.</p>
1141
1142
1143
1144
1145      </td>
1146
1147
1148
1149 </tr>
1150
1151
1152
1153 <tr>
1154
1155
1156
1157 <td style="vertical-align: top;"> 
1158     
1159     
1160     
1161      <p><a name="bc_s_t"></a><b>bc_s_t</b></p>
1162
1163
1164
1165
1166      </td>
1167
1168
1169
1170 <td style="vertical-align: top;">C * 20</td>
1171
1172
1173
1174
1175      <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1176
1177
1178
1179
1180      <td style="vertical-align: top;"> 
1181     
1182     
1183     
1184      <p style="font-style: normal;">Top boundary condition of the
1185scalar concentration.&nbsp; </p>
1186
1187
1188
1189 
1190     
1191     
1192     
1193      <p>Allowed are the
1194values <span style="font-style: italic;">'dirichlet'</span>
1195(s(k=nz) and s(k=nz+1) do
1196not change during the run) and <span style="font-style: italic;">'neumann'</span>.
1197With the Neumann boundary
1198condition the value of the scalar concentration gradient at the top is
1199calculated
1200from the initial scalar concentration profile (see <a href="#s_surface">s_surface</a>, <a href="#s_vertical_gradient">s_vertical_gradient</a>)
1201by: bc_s_t_val = (s_init(k=nz) - s_init(k=nz-1)) / dzu(nz).<br>
1202
1203
1204
1205
1206Using this value (assumed constant during the run) the concentration
1207boundary values
1208are calculated as </p>
1209
1210
1211
1212 
1213     
1214     
1215     
1216      <ul>
1217
1218
1219
1220 
1221       
1222       
1223       
1224        <p style="font-style: normal;">s(k=nz+1) = s(k=nz) +
1225bc_s_t_val * dzu(nz+1)</p>
1226
1227
1228
1229 
1230     
1231     
1232     
1233      </ul>
1234
1235
1236
1237 
1238     
1239     
1240     
1241      <p style="font-style: normal;">(up to k=nz the prognostic
1242equation for the scalar concentration is
1243solved).</p>
1244
1245
1246
1247 </td>
1248
1249
1250
1251 </tr>
1252
1253
1254
1255 <tr>
1256
1257
1258
1259      <td style="vertical-align: top;"><a name="bc_sa_t"></a><span style="font-weight: bold;">bc_sa_t</span></td>
1260
1261
1262
1263      <td style="vertical-align: top;">C * 20</td>
1264
1265
1266
1267      <td style="vertical-align: top;"><span style="font-style: italic;">'neumann'</span></td>
1268
1269
1270
1271      <td style="vertical-align: top;">
1272     
1273     
1274     
1275      <p style="font-style: normal;">Top boundary condition of the salinity.&nbsp; </p>
1276
1277
1278
1279 
1280     
1281     
1282     
1283      <p>This parameter only comes into effect for ocean runs (see parameter <a href="#ocean">ocean</a>).</p>
1284
1285
1286
1287     
1288     
1289     
1290      <p style="font-style: normal;">Allowed are the
1291values <span style="font-style: italic;">'dirichlet' </span>(sa(k=nz+1)
1292does not change during the run) and <span style="font-style: italic;">'neumann'</span>
1293(sa(k=nz+1)=sa(k=nz))<span style="font-style: italic;"></span>.&nbsp;<br>
1294
1295
1296
1297      <br>
1298
1299
1300
1301
1302When a constant salinity flux is used at the top boundary (<a href="chapter_4.1.html#top_salinityflux">top_salinityflux</a>),
1303      <b>bc_sa_t</b> = <span style="font-style: italic;">'neumann'</span>
1304must be used, because otherwise the resolved scale may contribute to
1305the top flux so that a constant value cannot be guaranteed.</p>
1306
1307
1308
1309      </td>
1310
1311
1312
1313    </tr>
1314
1315
1316
1317    <tr>
1318
1319
1320
1321 <td style="vertical-align: top;"> 
1322     
1323     
1324     
1325      <p><a name="bc_uv_b"></a><b>bc_uv_b</b></p>
1326
1327
1328
1329
1330      </td>
1331
1332
1333
1334 <td style="vertical-align: top;">C * 20</td>
1335
1336
1337
1338
1339      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1340
1341
1342
1343
1344      <td style="vertical-align: top;"> 
1345     
1346     
1347     
1348      <p style="font-style: normal;">Bottom boundary condition of the
1349horizontal velocity components u and v.&nbsp; </p>
1350
1351
1352
1353 
1354     
1355     
1356     
1357      <p>Allowed
1358values are <span style="font-style: italic;">'dirichlet' </span>and
1359      <span style="font-style: italic;">'neumann'</span>. <b>bc_uv_b</b>
1360= <span style="font-style: italic;">'dirichlet'</span>
1361yields the
1362no-slip condition with u=v=0 at the bottom. Due to the staggered grid
1363u(k=0) and v(k=0) are located at z = - 0,5 * <a href="#dz">dz</a>
1364(below the bottom), while u(k=1) and v(k=1) are located at z = +0,5 *
1365dz. u=v=0 at the bottom is guaranteed using mirror boundary
1366condition:&nbsp; </p>
1367
1368
1369
1370 
1371     
1372     
1373     
1374      <ul>
1375
1376
1377
1378 
1379       
1380       
1381       
1382        <p style="font-style: normal;">u(k=0) = - u(k=1) and v(k=0) = -
1383v(k=1)</p>
1384
1385
1386
1387 
1388     
1389     
1390     
1391      </ul>
1392
1393
1394
1395 
1396     
1397     
1398     
1399      <p style="font-style: normal;">The
1400Neumann boundary condition
1401yields the free-slip condition with u(k=0) = u(k=1) and v(k=0) =
1402v(k=1).
1403With Prandtl - layer switched on, the free-slip condition is not
1404allowed (otherwise the run will be terminated)<font color="#000000">.</font></p>
1405
1406
1407
1408
1409      </td>
1410
1411
1412
1413 </tr>
1414
1415
1416
1417 <tr>
1418
1419
1420
1421 <td style="vertical-align: top;"> 
1422     
1423     
1424     
1425      <p><a name="bc_uv_t"></a><b>bc_uv_t</b></p>
1426
1427
1428
1429
1430      </td>
1431
1432
1433
1434 <td style="vertical-align: top;">C * 20</td>
1435
1436
1437
1438
1439      <td style="vertical-align: top;"><span style="font-style: italic;">'dirichlet'</span></td>
1440
1441
1442
1443
1444      <td style="vertical-align: top;"> 
1445     
1446     
1447     
1448      <p style="font-style: normal;">Top boundary condition of the
1449horizontal velocity components u and v.&nbsp; </p>
1450
1451
1452
1453 
1454     
1455     
1456     
1457      <p>Allowed
1458values are <span style="font-style: italic;">'dirichlet'</span>
1459and <span style="font-style: italic;">'neumann'</span>.
1460The
1461Dirichlet condition yields u(k=nz+1) = ug(nz+1) and v(k=nz+1) =
1462vg(nz+1),
1463Neumann condition yields the free-slip condition with u(k=nz+1) =
1464u(k=nz) and v(k=nz+1) = v(k=nz) (up to k=nz the prognostic equations
1465for the velocities are solved).</p>
1466
1467
1468
1469     
1470     
1471     
1472      <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>
1473
1474
1475
1476 </td>
1477
1478
1479
1480 </tr>
1481
1482
1483
1484 <tr>
1485
1486
1487
1488      <td style="vertical-align: top;"><a name="bottom_salinityflux"></a><span style="font-weight: bold;">bottom_salinityflux</span></td>
1489
1490
1491
1492      <td style="vertical-align: top;">R</td>
1493
1494
1495
1496      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
1497
1498
1499
1500      <td style="vertical-align: top;">
1501     
1502     
1503     
1504      <p>Kinematic salinity flux near the surface (in psu m/s).&nbsp;</p>
1505
1506
1507
1508This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).
1509     
1510     
1511     
1512      <p>The
1513respective salinity flux value is used
1514as bottom (horizontally homogeneous) boundary condition for the salinity equation. This additionally requires that a Neumann
1515condition must be used for the salinity, which is currently the only available condition.<br>
1516
1517
1518
1519 </p>
1520
1521
1522
1523 </td>
1524
1525
1526
1527    </tr>
1528
1529
1530
1531    <tr>
1532
1533
1534
1535
1536      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_height"></a>building_height</span></td>
1537
1538
1539
1540
1541      <td style="vertical-align: top;">R</td>
1542
1543
1544
1545 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1546
1547
1548
1549 <td>Height
1550of a single building in m.<br>
1551
1552
1553
1554 <br>
1555
1556
1557
1558 <span style="font-weight: bold;">building_height</span> must
1559be less than the height of the model domain. This parameter requires
1560the use of&nbsp;<a href="#topography">topography</a>
1561= <span style="font-style: italic;">'single_building'</span>.</td>
1562
1563
1564
1565
1566    </tr>
1567
1568
1569
1570 <tr>
1571
1572
1573
1574 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_length_x"></a>building_length_x</span></td>
1575
1576
1577
1578
1579      <td style="vertical-align: top;">R</td>
1580
1581
1582
1583 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1584
1585
1586
1587 <td><span style="font-style: italic;"></span>Width of a single
1588building in m.<br>
1589
1590
1591
1592 <br>
1593
1594
1595
1596
1597Currently, <span style="font-weight: bold;">building_length_x</span>
1598must be at least <span style="font-style: italic;">3
1599*&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>
1600      </span><span style="font-style: italic;">- <a href="#building_wall_left">building_wall_left</a></span>.
1601This parameter requires the use of&nbsp;<a href="#topography">topography</a>
1602= <span style="font-style: italic;">'single_building'</span>.</td>
1603
1604
1605
1606
1607    </tr>
1608
1609
1610
1611 <tr>
1612
1613
1614
1615 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_length_y"></a>building_length_y</span></td>
1616
1617
1618
1619
1620      <td style="vertical-align: top;">R</td>
1621
1622
1623
1624 <td style="vertical-align: top;"><span style="font-style: italic;">50.0</span></td>
1625
1626
1627
1628 <td>Depth
1629of a single building in m.<br>
1630
1631
1632
1633 <br>
1634
1635
1636
1637
1638Currently, <span style="font-weight: bold;">building_length_y</span>
1639must be at least <span style="font-style: italic;">3
1640*&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
1641the use of&nbsp;<a href="#topography">topography</a>
1642= <span style="font-style: italic;">'single_building'</span>.</td>
1643
1644
1645
1646
1647    </tr>
1648
1649
1650
1651 <tr>
1652
1653
1654
1655 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_wall_left"></a>building_wall_left</span></td>
1656
1657
1658
1659
1660      <td style="vertical-align: top;">R</td>
1661
1662
1663
1664 <td style="vertical-align: top;"><span style="font-style: italic;">building centered in x-direction</span></td>
1665
1666
1667
1668
1669      <td>x-coordinate of the left building wall (distance between the
1670left building wall and the left border of the model domain) in m.<br>
1671
1672
1673
1674
1675      <br>
1676
1677
1678
1679
1680Currently, <span style="font-weight: bold;">building_wall_left</span>
1681must be at least <span style="font-style: italic;">1
1682*&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;
1683- 1 ) * <a href="#dx">dx</a> -&nbsp; <a href="#building_length_x">building_length_x</a></span>.
1684This parameter requires the use of&nbsp;<a href="#topography">topography</a>
1685= <span style="font-style: italic;">'single_building'</span>.<br>
1686
1687
1688
1689
1690      <br>
1691
1692
1693
1694
1695The default value&nbsp;<span style="font-weight: bold;">building_wall_left</span>
1696= <span style="font-style: italic;">( ( <a href="#nx">nx</a>&nbsp;+
16971 ) * <a href="#dx">dx</a> -&nbsp; <a href="#building_length_x">building_length_x</a> ) / 2</span>
1698centers the building in x-direction. </td>
1699
1700
1701
1702 </tr>
1703
1704
1705
1706 <tr>
1707
1708
1709
1710
1711      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="building_wall_south"></a>building_wall_south</span></td>
1712
1713
1714
1715
1716      <td style="vertical-align: top;">R</td>
1717
1718
1719
1720 <td style="vertical-align: top;"><span style="font-style: italic;"></span><span style="font-style: italic;">building centered in y-direction</span></td>
1721
1722
1723
1724
1725      <td>y-coordinate of the South building wall (distance between the
1726South building wall and the South border of the model domain) in m.<br>
1727
1728
1729
1730
1731      <br>
1732
1733
1734
1735
1736Currently, <span style="font-weight: bold;">building_wall_south</span>
1737must be at least <span style="font-style: italic;">1
1738*&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;
1739- 1 ) * <a href="#dy">dy</a> -&nbsp; <a href="#building_length_y">building_length_y</a></span>.
1740This parameter requires the use of&nbsp;<a href="#topography">topography</a>
1741= <span style="font-style: italic;">'single_building'</span>.<br>
1742
1743
1744
1745
1746      <br>
1747
1748
1749
1750
1751The default value&nbsp;<span style="font-weight: bold;">building_wall_south</span>
1752= <span style="font-style: italic;">( ( <a href="#ny">ny</a>&nbsp;+
17531 ) * <a href="#dy">dy</a> -&nbsp; <a href="#building_length_y">building_length_y</a> ) / 2</span>
1754centers the building in y-direction. </td>
1755
1756
1757
1758 </tr>
1759
1760
1761
1762 <tr>
1763
1764
1765
1766
1767      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="cloud_droplets"></a>cloud_droplets</span><br>
1768
1769
1770
1771
1772      </td>
1773
1774
1775
1776 <td style="vertical-align: top;">L<br>
1777
1778
1779
1780 </td>
1781
1782
1783
1784
1785      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span><br>
1786
1787
1788
1789 </td>
1790
1791
1792
1793
1794      <td style="vertical-align: top;">Parameter to switch on
1795usage of cloud droplets.<br>
1796
1797
1798
1799 <br>
1800
1801
1802
1803
1804Cloud droplets require to use the particle package (<span style="font-weight: bold;">mrun</span>-option <span style="font-family: monospace;">-p particles</span>),
1805so in this case a particle corresponds to a droplet. The droplet
1806features (number of droplets, initial radius, etc.) can be steered with
1807the&nbsp; respective particle parameters (see e.g. <a href="#chapter_4.2.html#radius">radius</a>).
1808The real number of initial droplets in a grid cell is equal to the
1809initial 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>
1810      <span lang="en-GB"><font face="Thorndale, serif">and
1811      </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>)
1812times the <a href="#initial_weighting_factor">initial_weighting_factor</a>.<br>
1813
1814
1815
1816
1817      <br>
1818
1819
1820
1821
1822In case of using cloud droplets, the default condensation scheme in
1823PALM cannot be used, i.e. <a href="#cloud_physics">cloud_physics</a>
1824must be set <span style="font-style: italic;">.F.</span>.<br>
1825
1826
1827
1828
1829      </td>
1830
1831
1832
1833 </tr>
1834
1835
1836
1837 <tr>
1838
1839
1840
1841 <td style="vertical-align: top;"> 
1842     
1843     
1844     
1845      <p><a name="cloud_physics"></a><b>cloud_physics</b></p>
1846
1847
1848
1849
1850      </td>
1851
1852
1853
1854 <td style="vertical-align: top;">L<br>
1855
1856
1857
1858 </td>
1859
1860
1861
1862
1863      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
1864
1865
1866
1867 <td style="vertical-align: top;"> 
1868     
1869     
1870     
1871      <p>Parameter to switch
1872on the condensation scheme.&nbsp; </p>
1873
1874
1875
1876
1877For <b>cloud_physics =</b> <span style="font-style: italic;">.TRUE.</span>, equations
1878for the
1879liquid water&nbsp;
1880content and the liquid water potential temperature are solved instead
1881of those for specific humidity and potential temperature. Note
1882that a grid volume is assumed to be either completely saturated or
1883completely
1884unsaturated (0%-or-100%-scheme). A simple precipitation scheme can
1885additionally be switched on with parameter <a href="#precipitation">precipitation</a>.
1886Also cloud-top cooling by longwave radiation can be utilized (see <a href="#radiation">radiation</a>)<br>
1887
1888
1889
1890 <b><br>
1891
1892
1893
1894
1895cloud_physics =</b> <span style="font-style: italic;">.TRUE.
1896      </span>requires&nbsp;<a href="#humidity">humidity</a>
1897=<span style="font-style: italic;"> .TRUE.</span> .<br>
1898
1899
1900
1901
1902Detailed information about the condensation scheme is given in the
1903description of the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM-1/Dokumentationen/Cloud_physics/wolken.pdf">cloud
1904physics module</a> (pdf-file, only in German).<br>
1905
1906
1907
1908 <br>
1909
1910
1911
1912
1913This condensation scheme is not allowed if cloud droplets are simulated
1914explicitly (see <a href="#cloud_droplets">cloud_droplets</a>).<br>
1915
1916
1917
1918
1919      </td>
1920
1921
1922
1923 </tr>
1924
1925
1926
1927 <tr>
1928
1929
1930
1931 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="conserve_volume_flow"></a>conserve_volume_flow</span></td>
1932
1933
1934
1935
1936      <td style="vertical-align: top;">L</td>
1937
1938
1939
1940 <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
1941
1942
1943
1944 <td>Conservation
1945of volume flow in x- and y-direction.<br>
1946
1947
1948
1949 <br>
1950
1951
1952
1953 <span style="font-weight: bold;">conserve_volume_flow</span>
1954= <span style="font-style: italic;">.TRUE.</span>
1955guarantees that the volume flow through the xz- or yz-cross-section of
1956the total model domain remains constant (equal to the initial value at
1957t=0) throughout the run.<br>
1958
1959
1960
1961
1962      </td>
1963
1964
1965
1966 </tr>
1967
1968
1969
1970 <tr>
1971
1972
1973
1974 <td style="vertical-align: top;"> 
1975     
1976     
1977     
1978      <p><a name="cut_spline_overshoot"></a><b>cut_spline_overshoot</b></p>
1979
1980
1981
1982
1983      </td>
1984
1985
1986
1987 <td style="vertical-align: top;">L</td>
1988
1989
1990
1991
1992      <td style="vertical-align: top;"><span style="font-style: italic;">.T.</span></td>
1993
1994
1995
1996 <td style="vertical-align: top;"> 
1997     
1998     
1999     
2000      <p>Cuts off of
2001so-called overshoots, which can occur with the
2002upstream-spline scheme.&nbsp; </p>
2003
2004
2005
2006 
2007     
2008     
2009     
2010      <p><font color="#000000">The cubic splines tend to overshoot in
2011case of discontinuous changes of variables between neighbouring grid
2012points.</font><font color="#ff0000"> </font><font color="#000000">This
2013may lead to errors in calculating the advection tendency.</font>
2014Choice
2015of <b>cut_spline_overshoot</b> = <i>.TRUE.</i>
2016(switched on by
2017default)
2018allows variable values not to exceed an interval defined by the
2019respective adjacent grid points. This interval can be adjusted
2020seperately for every prognostic variable (see initialization parameters
2021      <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>,
2022etc.). This might be necessary in case that the
2023default interval has a non-tolerable effect on the model
2024results.&nbsp; </p>
2025
2026
2027
2028 
2029     
2030     
2031     
2032      <p>Overshoots may also be removed
2033using the parameters <a href="#ups_limit_e">ups_limit_e</a>,
2034      <a href="#ups_limit_pt">ups_limit_pt</a>,
2035etc. as well as by applying a long-filter (see <a href="#long_filter_factor">long_filter_factor</a>).</p>
2036
2037
2038
2039
2040      </td>
2041
2042
2043
2044 </tr>
2045
2046
2047
2048 <tr>
2049
2050
2051
2052 <td style="vertical-align: top;"> 
2053     
2054     
2055     
2056      <p><a name="damp_level_1d"></a><b>damp_level_1d</b></p>
2057
2058
2059
2060
2061      </td>
2062
2063
2064
2065 <td style="vertical-align: top;">R</td>
2066
2067
2068
2069
2070      <td style="vertical-align: top;"><span style="font-style: italic;">zu(nz+1)</span></td>
2071
2072
2073
2074
2075      <td style="vertical-align: top;"> 
2076     
2077     
2078     
2079      <p>Height where
2080the damping layer begins in the 1d-model
2081(in m).&nbsp; </p>
2082
2083
2084
2085 
2086     
2087     
2088     
2089      <p>This parameter is used to
2090switch on a damping layer for the
20911d-model, which is generally needed for the damping of inertia
2092oscillations. Damping is done by gradually increasing the value
2093of the eddy diffusivities about 10% per vertical grid level
2094(starting with the value at the height given by <b>damp_level_1d</b>,
2095or possibly from the next grid pint above), i.e. K<sub>m</sub>(k+1)
2096=
20971.1 * K<sub>m</sub>(k).
2098The values of K<sub>m</sub> are limited to 10 m**2/s at
2099maximum.&nbsp; <br>
2100
2101
2102
2103
2104This parameter only comes into effect if the 1d-model is switched on
2105for
2106the initialization of the 3d-model using <a href="#initializing_actions">initializing_actions</a>
2107= <span style="font-style: italic;">'set_1d-model_profiles'</span>.
2108      <br>
2109
2110
2111
2112 </p>
2113
2114
2115
2116 </td>
2117
2118
2119
2120 </tr>
2121
2122
2123
2124 <tr>
2125
2126
2127
2128 <td style="vertical-align: top;"><a name="dissipation_1d"></a><span style="font-weight: bold;">dissipation_1d</span><br>
2129
2130
2131
2132
2133      </td>
2134
2135
2136
2137 <td style="vertical-align: top;">C*20<br>
2138
2139
2140
2141
2142      </td>
2143
2144
2145
2146 <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
2147
2148
2149
2150 <span style="font-style: italic;">model'</span><br>
2151
2152
2153
2154 </td>
2155
2156
2157
2158
2159      <td style="vertical-align: top;">Calculation method for
2160the energy dissipation term in the TKE equation of the 1d-model.<br>
2161
2162
2163
2164
2165      <br>
2166
2167
2168
2169
2170By default the dissipation is calculated as in the 3d-model using diss
2171= (0.19 + 0.74 * l / l_grid) * e**1.5 / l.<br>
2172
2173
2174
2175 <br>
2176
2177
2178
2179
2180Setting <span style="font-weight: bold;">dissipation_1d</span>
2181= <span style="font-style: italic;">'detering'</span>
2182forces the dissipation to be calculated as diss = 0.064 * e**1.5 / l.<br>
2183
2184
2185
2186
2187      </td>
2188
2189
2190
2191 </tr>
2192
2193
2194
2195
2196    <tr>
2197
2198
2199
2200 <td style="vertical-align: top;"> 
2201     
2202     
2203     
2204      <p><a name="dt"></a><b>dt</b></p>
2205
2206
2207
2208 </td>
2209
2210
2211
2212
2213      <td style="vertical-align: top;">R</td>
2214
2215
2216
2217 <td style="vertical-align: top;"><span style="font-style: italic;">variable</span></td>
2218
2219
2220
2221
2222      <td style="vertical-align: top;"> 
2223     
2224     
2225     
2226      <p>Time step for
2227the 3d-model (in s).&nbsp; </p>
2228
2229
2230
2231 
2232     
2233     
2234     
2235      <p>By default, (i.e.
2236if a Runge-Kutta scheme is used, see <a href="#timestep_scheme">timestep_scheme</a>)
2237the value of the time step is calculating after each time step
2238(following the time step criteria) and
2239used for the next step.</p>
2240
2241
2242
2243 
2244     
2245     
2246     
2247      <p>If the user assigns <b>dt</b>
2248a value, then the time step is
2249fixed to this value throughout the whole run (whether it fulfills the
2250time step
2251criteria or not). However, changes are allowed for restart runs,
2252because <b>dt</b> can also be used as a <a href="chapter_4.2.html#dt_laufparameter">run
2253parameter</a>.&nbsp; </p>
2254
2255
2256
2257 
2258     
2259     
2260     
2261      <p>In case that the
2262calculated time step meets the condition<br>
2263
2264
2265
2266 </p>
2267
2268
2269
2270 
2271     
2272     
2273     
2274      <ul>
2275
2276
2277
2278
2279       
2280       
2281       
2282        <p><b>dt</b> &lt; 0.00001 * <a href="chapter_4.2.html#dt_max">dt_max</a> (with dt_max
2283= 20.0)</p>
2284
2285
2286
2287 
2288     
2289     
2290     
2291      </ul>
2292
2293
2294
2295 
2296     
2297     
2298     
2299      <p>the simulation will be
2300aborted. Such situations usually arise
2301in case of any numerical problem / instability which causes a
2302non-realistic increase of the wind speed.&nbsp; </p>
2303
2304
2305
2306 
2307     
2308     
2309     
2310      <p>A
2311small time step due to a large mean horizontal windspeed
2312speed may be enlarged by using a coordinate transformation (see <a href="#galilei_transformation">galilei_transformation</a>),
2313in order to spare CPU time.<br>
2314
2315
2316
2317 </p>
2318
2319
2320
2321 
2322     
2323     
2324     
2325      <p>If the
2326leapfrog timestep scheme is used (see <a href="#timestep_scheme">timestep_scheme</a>)
2327a temporary time step value dt_new is calculated first, with dt_new = <a href="chapter_4.2.html#fcl_factor">cfl_factor</a>
2328* dt_crit where dt_crit is the maximum timestep allowed by the CFL and
2329diffusion condition. Next it is examined whether dt_new exceeds or
2330falls below the
2331value of the previous timestep by at
2332least +5 % / -2%. If it is smaller, <span style="font-weight: bold;">dt</span>
2333= dt_new is immediately used for the next timestep. If it is larger,
2334then <span style="font-weight: bold;">dt </span>=
23351.02 * dt_prev
2336(previous timestep) is used as the new timestep, however the time
2337step is only increased if the last change of the time step is dated
2338back at
2339least 30 iterations. If dt_new is located in the interval mentioned
2340above, then dt
2341does not change at all. By doing so, permanent time step changes as
2342well as large
2343sudden changes (increases) in the time step are avoided.</p>
2344
2345
2346
2347 </td>
2348
2349
2350
2351
2352    </tr>
2353
2354
2355
2356 <tr>
2357
2358
2359
2360 <td style="vertical-align: top;">
2361     
2362     
2363     
2364      <p><a name="dt_pr_1d"></a><b>dt_pr_1d</b></p>
2365
2366
2367
2368
2369      </td>
2370
2371
2372
2373 <td style="vertical-align: top;">R</td>
2374
2375
2376
2377
2378      <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
2379
2380
2381
2382
2383      <td style="vertical-align: top;"> 
2384     
2385     
2386     
2387      <p>Temporal
2388interval of vertical profile output of the 1D-model
2389(in s).&nbsp; </p>
2390
2391
2392
2393 
2394     
2395     
2396     
2397      <p>Data are written in ASCII
2398format to file <a href="chapter_3.4.html#LIST_PROFIL_1D">LIST_PROFIL_1D</a>.
2399This parameter is only in effect if the 1d-model has been switched on
2400for the
2401initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
2402= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
2403
2404
2405
2406
2407      </td>
2408
2409
2410
2411 </tr>
2412
2413
2414
2415 <tr>
2416
2417
2418
2419 <td style="vertical-align: top;"> 
2420     
2421     
2422     
2423      <p><a name="dt_run_control_1d"></a><b>dt_run_control_1d</b></p>
2424
2425
2426
2427
2428      </td>
2429
2430
2431
2432 <td style="vertical-align: top;">R</td>
2433
2434
2435
2436
2437      <td style="vertical-align: top;"><span style="font-style: italic;">60.0</span></td>
2438
2439
2440
2441 <td style="vertical-align: top;"> 
2442     
2443     
2444     
2445      <p>Temporal interval of
2446runtime control output of the 1d-model
2447(in s).&nbsp; </p>
2448
2449
2450
2451 
2452     
2453     
2454     
2455      <p>Data are written in ASCII
2456format to file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.
2457This parameter is only in effect if the 1d-model is switched on for the
2458initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
2459= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
2460
2461
2462
2463
2464      </td>
2465
2466
2467
2468 </tr>
2469
2470
2471
2472 <tr>
2473
2474
2475
2476 <td style="vertical-align: top;"> 
2477     
2478     
2479     
2480      <p><a name="dx"></a><b>dx</b></p>
2481
2482
2483
2484
2485      </td>
2486
2487
2488
2489 <td style="vertical-align: top;">R</td>
2490
2491
2492
2493
2494      <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
2495
2496
2497
2498 <td style="vertical-align: top;"> 
2499     
2500     
2501     
2502      <p>Horizontal grid
2503spacing along the x-direction (in m).&nbsp; </p>
2504
2505
2506
2507 
2508     
2509     
2510     
2511      <p>Along
2512x-direction only a constant grid spacing is allowed.</p>
2513
2514
2515
2516     
2517     
2518     
2519      <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>
2520and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
2521
2522
2523
2524 </td>
2525
2526
2527
2528
2529    </tr>
2530
2531
2532
2533 <tr>
2534
2535
2536
2537 <td style="vertical-align: top;">
2538     
2539     
2540     
2541      <p><a name="dy"></a><b>dy</b></p>
2542
2543
2544
2545
2546      </td>
2547
2548
2549
2550 <td style="vertical-align: top;">R</td>
2551
2552
2553
2554
2555      <td style="vertical-align: top;"><span style="font-style: italic;">1.0</span></td>
2556
2557
2558
2559 <td style="vertical-align: top;"> 
2560     
2561     
2562     
2563      <p>Horizontal grid
2564spacing along the y-direction (in m).&nbsp; </p>
2565
2566
2567
2568 
2569     
2570     
2571     
2572      <p>Along y-direction only a constant grid spacing is allowed.</p>
2573
2574
2575
2576     
2577     
2578     
2579      <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>
2580and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
2581
2582
2583
2584 </td>
2585
2586
2587
2588
2589    </tr>
2590
2591
2592
2593 <tr>
2594
2595
2596
2597 <td style="vertical-align: top;">
2598     
2599     
2600     
2601      <p><a name="dz"></a><b>dz</b></p>
2602
2603
2604
2605
2606      </td>
2607
2608
2609
2610 <td style="vertical-align: top;">R</td>
2611
2612
2613
2614
2615      <td style="vertical-align: top;"><br>
2616
2617
2618
2619 </td>
2620
2621
2622
2623 <td style="vertical-align: top;"> 
2624     
2625     
2626     
2627      <p>Vertical grid
2628spacing (in m).&nbsp; </p>
2629
2630
2631
2632 
2633     
2634     
2635     
2636      <p>This parameter must be
2637assigned by the user, because no
2638default value is given.<br>
2639
2640
2641
2642 </p>
2643
2644
2645
2646 
2647     
2648     
2649     
2650      <p>By default, the
2651model uses constant grid spacing along z-direction, but it can be
2652stretched using the parameters <a href="#dz_stretch_level">dz_stretch_level</a>
2653and <a href="#dz_stretch_factor">dz_stretch_factor</a>.
2654In case of stretching, a maximum allowed grid spacing can be given by <a href="#dz_max">dz_max</a>.<br>
2655
2656
2657
2658 </p>
2659
2660
2661
2662 
2663     
2664     
2665     
2666      <p>Assuming
2667a constant <span style="font-weight: bold;">dz</span>,
2668the scalar levels (zu) are calculated directly by:&nbsp; </p>
2669
2670
2671
2672
2673     
2674     
2675     
2676      <ul>
2677
2678
2679
2680 
2681       
2682       
2683       
2684        <p>zu(0) = - dz * 0.5&nbsp; <br>
2685
2686
2687
2688
2689zu(1) = dz * 0.5</p>
2690
2691
2692
2693 
2694     
2695     
2696     
2697      </ul>
2698
2699
2700
2701 
2702     
2703     
2704     
2705      <p>The w-levels lie
2706half between them:&nbsp; </p>
2707
2708
2709
2710 
2711     
2712     
2713     
2714      <ul>
2715
2716
2717
2718 
2719       
2720       
2721       
2722        <p>zw(k) =
2723( zu(k) + zu(k+1) ) * 0.5</p>
2724
2725
2726
2727 
2728     
2729     
2730     
2731      </ul>
2732
2733
2734
2735 </td>
2736
2737
2738
2739 </tr>
2740
2741
2742
2743
2744    <tr>
2745
2746
2747
2748      <td style="vertical-align: top;"><a name="dz_max"></a><span style="font-weight: bold;">dz_max</span></td>
2749
2750
2751
2752      <td style="vertical-align: top;">R</td>
2753
2754
2755
2756      <td style="vertical-align: top;"><span style="font-style: italic;">9999999.9</span></td>
2757
2758
2759
2760      <td style="vertical-align: top;">Allowed maximum vertical grid
2761spacing (in m).<br>
2762
2763
2764
2765      <br>
2766
2767
2768
2769If the vertical grid is stretched
2770(see <a href="#dz_stretch_factor">dz_stretch_factor</a>
2771and <a href="#dz_stretch_level">dz_stretch_level</a>),
2772      <span style="font-weight: bold;">dz_max</span> can
2773be used to limit the vertical grid spacing.</td>
2774
2775
2776
2777    </tr>
2778
2779
2780
2781    <tr>
2782
2783
2784
2785
2786      <td style="vertical-align: top;"> 
2787     
2788     
2789     
2790      <p><a name="dz_stretch_factor"></a><b>dz_stretch_factor</b></p>
2791
2792
2793
2794
2795      </td>
2796
2797
2798
2799 <td style="vertical-align: top;">R</td>
2800
2801
2802
2803
2804      <td style="vertical-align: top;"><span style="font-style: italic;">1.08</span></td>
2805
2806
2807
2808 <td style="vertical-align: top;"> 
2809     
2810     
2811     
2812      <p>Stretch factor for a
2813vertically stretched grid (see <a href="#dz_stretch_level">dz_stretch_level</a>).&nbsp;
2814      </p>
2815
2816
2817
2818 
2819     
2820     
2821     
2822      <p>The stretch factor should not exceed a value of
2823approx. 1.10 -
28241.12, otherwise the discretization errors due to the stretched grid not
2825negligible any more. (refer Kalnay de Rivas)</p>
2826
2827
2828
2829 </td>
2830
2831
2832
2833 </tr>
2834
2835
2836
2837
2838    <tr>
2839
2840
2841
2842 <td style="vertical-align: top;"> 
2843     
2844     
2845     
2846      <p><a name="dz_stretch_level"></a><b>dz_stretch_level</b></p>
2847
2848
2849
2850
2851      </td>
2852
2853
2854
2855 <td style="vertical-align: top;">R</td>
2856
2857
2858
2859
2860      <td style="vertical-align: top;"><span style="font-style: italic;">100000.0</span><br>
2861
2862
2863
2864 </td>
2865
2866
2867
2868
2869      <td style="vertical-align: top;"> 
2870     
2871     
2872     
2873      <p>Height level
2874above/below which the grid is to be stretched
2875vertically (in m).&nbsp; </p>
2876
2877
2878
2879 
2880     
2881     
2882     
2883      <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
2884vertically. The vertical grid
2885spacings <a href="#dz">dz</a>
2886above this level are calculated as&nbsp; </p>
2887
2888
2889
2890 
2891     
2892     
2893     
2894      <ul>
2895
2896
2897
2898 
2899       
2900       
2901       
2902        <p><b>dz</b>(k+1)
2903= <b>dz</b>(k) * <a href="#dz_stretch_factor">dz_stretch_factor</a></p>
2904
2905
2906
2907
2908     
2909     
2910     
2911      </ul>
2912
2913
2914
2915 
2916     
2917     
2918     
2919      <p>and used as spacings for the scalar levels (zu).
2920The
2921w-levels are then defined as:&nbsp; </p>
2922
2923
2924
2925 
2926     
2927     
2928     
2929      <ul>
2930
2931
2932
2933 
2934       
2935       
2936       
2937        <p>zw(k)
2938= ( zu(k) + zu(k+1) ) * 0.5.
2939
2940 
2941     
2942      </p>
2943
2944     
2945      </ul>
2946
2947     
2948      <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
2949vertically. The vertical grid
2950spacings <a href="chapter_4.1.html#dz">dz</a> below this level are calculated correspondingly as
2951
2952 
2953     
2954      </p>
2955
2956     
2957      <ul>
2958
2959       
2960        <p><b>dz</b>(k-1)
2961= <b>dz</b>(k) * <a href="chapter_4.1.html#dz_stretch_factor">dz_stretch_factor</a>.</p>
2962
2963     
2964      </ul>
2965
2966
2967
2968 </td>
2969
2970
2971
2972 </tr>
2973
2974
2975
2976
2977    <tr>
2978
2979
2980      <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_init"></a>e_init</span></td>
2981
2982
2983      <td style="vertical-align: top;">R</td>
2984
2985
2986      <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
2987
2988
2989      <td>Initial subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
2990
2991
2992
2993
2994      <br>
2995
2996
2997
2998This
2999option 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>
3000
3001
3002    </tr>
3003
3004
3005    <tr>
3006
3007
3008
3009 <td style="vertical-align: top;"><span style="font-weight: bold;"><a name="e_min"></a>e_min</span></td>
3010
3011
3012
3013
3014      <td style="vertical-align: top;">R</td>
3015
3016
3017
3018 <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span></td>
3019
3020
3021
3022 <td>Minimum
3023subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
3024
3025
3026
3027
3028      <br>
3029
3030
3031
3032This
3033option&nbsp;adds artificial viscosity to the flow by ensuring that
3034the
3035subgrid-scale TKE does not fall below the minimum threshold <span style="font-weight: bold;">e_min</span>.</td>
3036
3037
3038
3039 </tr>
3040
3041
3042
3043
3044    <tr>
3045
3046
3047
3048 <td style="vertical-align: top;"> 
3049     
3050     
3051     
3052      <p><a name="end_time_1d"></a><b>end_time_1d</b></p>
3053
3054
3055
3056
3057      </td>
3058
3059
3060
3061 <td style="vertical-align: top;">R</td>
3062
3063
3064
3065
3066      <td style="vertical-align: top;"><span style="font-style: italic;">864000.0</span><br>
3067
3068
3069
3070 </td>
3071
3072
3073
3074
3075      <td style="vertical-align: top;"> 
3076     
3077     
3078     
3079      <p>Time to be
3080simulated for the 1d-model (in s).&nbsp; </p>
3081
3082
3083
3084 
3085     
3086     
3087     
3088      <p>The
3089default value corresponds to a simulated time of 10 days.
3090Usually, after such a period the inertia oscillations have completely
3091decayed and the solution of the 1d-model can be regarded as stationary
3092(see <a href="#damp_level_1d">damp_level_1d</a>).
3093This parameter is only in effect if the 1d-model is switched on for the
3094initialization of the 3d-model with <a href="#initializing_actions">initializing_actions</a>
3095= <span style="font-style: italic;">'set_1d-model_profiles'</span>.</p>
3096
3097
3098
3099
3100      </td>
3101
3102
3103
3104 </tr>
3105
3106
3107
3108 <tr>
3109
3110
3111
3112 <td style="vertical-align: top;"> 
3113     
3114     
3115     
3116      <p><a name="fft_method"></a><b>fft_method</b></p>
3117
3118
3119
3120
3121      </td>
3122
3123
3124
3125 <td style="vertical-align: top;">C * 20</td>
3126
3127
3128
3129
3130      <td style="vertical-align: top;"><span style="font-style: italic;">'system-</span><br style="font-style: italic;">
3131
3132
3133
3134 <span style="font-style: italic;">specific'</span></td>
3135
3136
3137
3138
3139      <td style="vertical-align: top;"> 
3140     
3141     
3142     
3143      <p>FFT-method to
3144be used.<br>
3145
3146
3147
3148 </p>
3149
3150
3151
3152 
3153     
3154     
3155     
3156      <p><br>
3157
3158
3159
3160
3161The fast fourier transformation (FFT) is used for solving the
3162perturbation pressure equation with a direct method (see <a href="chapter_4.2.html#psolver">psolver</a>)
3163and for calculating power spectra (see optional software packages,
3164section <a href="chapter_4.2.html#spectra_package">4.2</a>).</p>
3165
3166
3167
3168
3169     
3170     
3171     
3172      <p><br>
3173
3174
3175
3176
3177By default, system-specific, optimized routines from external
3178vendor libraries are used. However, these are available only on certain
3179computers and there are more or less severe restrictions concerning the
3180number of gridpoints to be used with them.<br>
3181
3182
3183
3184 </p>
3185
3186
3187
3188 
3189     
3190     
3191     
3192      <p>There
3193are two other PALM internal methods available on every
3194machine (their respective source code is part of the PALM source code):</p>
3195
3196
3197
3198
3199     
3200     
3201     
3202      <p>1.: The <span style="font-weight: bold;">Temperton</span>-method
3203from Clive Temperton (ECWMF) which is computationally very fast and
3204switched on with <b>fft_method</b> = <span style="font-style: italic;">'temperton-algorithm'</span>.
3205The number of horizontal gridpoints (nx+1, ny+1) to be used with this
3206method must be composed of prime factors 2, 3 and 5.<br>
3207
3208
3209
3210 </p>
3211
3212
3213
3214
32152.: The <span style="font-weight: bold;">Singleton</span>-method
3216which is very slow but has no restrictions concerning the number of
3217gridpoints to be used with, switched on with <b>fft_method</b>
3218= <span style="font-style: italic;">'singleton-algorithm'</span>.
3219      </td>
3220
3221
3222
3223 </tr>
3224
3225
3226
3227 <tr>
3228
3229
3230
3231 <td style="vertical-align: top;"> 
3232     
3233     
3234     
3235      <p><a name="galilei_transformation"></a><b>galilei_transformation</b></p>
3236
3237
3238
3239
3240      </td>
3241
3242
3243
3244 <td style="vertical-align: top;">L</td>
3245
3246
3247
3248
3249      <td style="vertical-align: top;"><i>.F.</i></td>
3250
3251
3252
3253
3254      <td style="vertical-align: top;">Application of a
3255Galilei-transformation to the
3256coordinate
3257system of the model.<br>
3258
3259
3260
3261     
3262     
3263     
3264      <p>With <b>galilei_transformation</b>
3265= <i>.T.,</i> a so-called
3266Galilei-transformation is switched on which ensures that the coordinate
3267system of the model is moved along with the geostrophical wind.
3268Alternatively, the model domain can be moved along with the averaged
3269horizontal wind (see <a href="#use_ug_for_galilei_tr">use_ug_for_galilei_tr</a>,
3270this can and will naturally change in time). With this method,
3271numerical inaccuracies of the Piascek - Williams - scheme (concerns in
3272particular the momentum advection) are minimized. Beyond that, in the
3273majority of cases the lower relative velocities in the moved system
3274permit a larger time step (<a href="#dt">dt</a>).
3275Switching the transformation on is only worthwhile if the geostrophical
3276wind (ug, vg)
3277and the averaged horizontal wind clearly deviate from the value 0. In
3278each case, the distance the coordinate system has been moved is written
3279to the file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.&nbsp;
3280      </p>
3281
3282
3283
3284 
3285     
3286     
3287     
3288      <p>Non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
3289and <a href="#bc_ns">bc_ns</a>), the specification
3290of a gestrophic
3291wind that is not constant with height
3292as well as e.g. stationary inhomogeneities at the bottom boundary do
3293not allow the use of this transformation.</p>
3294
3295
3296
3297 </td>
3298
3299
3300
3301 </tr>
3302
3303
3304
3305
3306    <tr>
3307
3308
3309
3310 <td style="vertical-align: top;"> 
3311     
3312     
3313     
3314      <p><a name="grid_matching"></a><b>grid_matching</b></p>
3315
3316
3317
3318
3319      </td>
3320
3321
3322
3323 <td style="vertical-align: top;">C * 6</td>
3324
3325
3326
3327
3328      <td style="vertical-align: top;"><span style="font-style: italic;">'match'</span></td>
3329
3330
3331
3332 <td style="vertical-align: top;">Variable to adjust the
3333subdomain
3334sizes in parallel runs.<br>
3335
3336
3337
3338 <br>
3339
3340
3341
3342
3343For <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>,
3344the subdomains are forced to have an identical
3345size on all processors. In this case the processor numbers in the
3346respective directions of the virtual processor net must fulfill certain
3347divisor conditions concerning the grid point numbers in the three
3348directions (see <a href="#nx">nx</a>, <a href="#ny">ny</a>
3349and <a href="#nz">nz</a>).
3350Advantage of this method is that all PEs bear the same computational
3351load.<br>
3352
3353
3354
3355 <br>
3356
3357
3358
3359
3360There is no such restriction by default, because then smaller
3361subdomains are allowed on those processors which
3362form the right and/or north boundary of the virtual processor grid. On
3363all other processors the subdomains are of same size. Whether smaller
3364subdomains are actually used, depends on the number of processors and
3365the grid point numbers used. Information about the respective settings
3366are 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>
3367
3368
3369
3370
3371      <br>
3372
3373
3374
3375
3376When 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>)
3377only <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>
3378is allowed.<br>
3379
3380
3381
3382 <br>
3383
3384
3385
3386 <b>Note:</b><br>
3387
3388
3389
3390
3391In some cases for small processor numbers there may be a very bad load
3392balancing among the
3393processors which may reduce the performance of the code.</td>
3394
3395
3396
3397 </tr>
3398
3399
3400
3401
3402    <tr>
3403
3404
3405
3406 <td style="vertical-align: top;"><a name="inflow_disturbance_begin"></a><b>inflow_disturbance_<br>
3407
3408
3409
3410
3411begin</b></td>
3412
3413
3414
3415 <td style="vertical-align: top;">I</td>
3416
3417
3418
3419
3420      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(10,</span><br style="font-style: italic;">
3421
3422
3423
3424 <span style="font-style: italic;">nx/2 or ny/2)</span></td>
3425
3426
3427
3428
3429      <td style="vertical-align: top;">Lower
3430limit of the horizontal range for which random perturbations are to be
3431imposed on the horizontal velocity field (gridpoints).<br>
3432
3433
3434
3435 <br>
3436
3437
3438
3439
3440If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
3441or <a href="#bc_ns">bc_ns</a>),
3442this parameter gives the gridpoint number (counted horizontally from
3443the inflow)&nbsp; from which on perturbations are imposed on the
3444horizontal velocity field. Perturbations must be switched on with
3445parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
3446
3447
3448
3449
3450    </tr>
3451
3452
3453
3454 <tr>
3455
3456
3457
3458 <td style="vertical-align: top;"><a name="inflow_disturbance_end"></a><b>inflow_disturbance_<br>
3459
3460
3461
3462
3463end</b></td>
3464
3465
3466
3467 <td style="vertical-align: top;">I</td>
3468
3469
3470
3471
3472      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(100,</span><br style="font-style: italic;">
3473
3474
3475
3476 <span style="font-style: italic;">3/4*nx or</span><br style="font-style: italic;">
3477
3478
3479
3480 <span style="font-style: italic;">3/4*ny)</span></td>
3481
3482
3483
3484 <td style="vertical-align: top;">Upper
3485limit of the horizontal range for which random perturbations are
3486to be imposed on the horizontal velocity field (gridpoints).<br>
3487
3488
3489
3490 <br>
3491
3492
3493
3494
3495If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
3496or <a href="#bc_ns">bc_ns</a>),
3497this parameter gives the gridpoint number (counted horizontally from
3498the inflow)&nbsp; unto which perturbations are imposed on the
3499horizontal
3500velocity field. Perturbations must be switched on with parameter <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>.</td>
3501
3502
3503
3504
3505    </tr>
3506
3507
3508
3509 <tr>
3510
3511
3512
3513 <td style="vertical-align: top;">
3514     
3515     
3516     
3517      <p><a name="initializing_actions"></a><b>initializing_actions</b></p>
3518
3519
3520
3521
3522      </td>
3523
3524
3525
3526 <td style="vertical-align: top;">C * 100</td>
3527
3528
3529
3530
3531      <td style="vertical-align: top;"><br>
3532
3533
3534
3535 </td>
3536
3537
3538
3539 <td style="vertical-align: top;"> 
3540     
3541     
3542     
3543      <p style="font-style: normal;">Initialization actions
3544to be carried out.&nbsp; </p>
3545
3546
3547
3548 
3549     
3550     
3551     
3552      <p style="font-style: normal;">This parameter does not have a
3553default value and therefore must be assigned with each model run. For
3554restart runs <b>initializing_actions</b> = <span style="font-style: italic;">'read_restart_data'</span>
3555must be set. For the initial run of a job chain the following values
3556are allowed:&nbsp; </p>
3557
3558
3559
3560 
3561     
3562     
3563     
3564      <p style="font-style: normal;"><span style="font-style: italic;">'set_constant_profiles'</span>
3565      </p>
3566
3567
3568
3569 
3570     
3571     
3572     
3573      <ul>
3574
3575
3576
3577 
3578       
3579       
3580       
3581        <p>A horizontal wind profile consisting
3582of linear sections (see <a href="#ug_surface">ug_surface</a>,
3583        <a href="#ug_vertical_gradient">ug_vertical_gradient</a>,
3584        <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>
3585and <a href="#vg_surface">vg_surface</a>, <a href="#vg_vertical_gradient">vg_vertical_gradient</a>,
3586        <a href="#vg_vertical_gradient_level">vg_vertical_gradient_level</a>,
3587respectively) as well as a vertical temperature (humidity) profile
3588consisting of
3589linear sections (see <a href="#pt_surface">pt_surface</a>,
3590        <a href="#pt_vertical_gradient">pt_vertical_gradient</a>,
3591        <a href="#q_surface">q_surface</a>
3592and <a href="#q_vertical_gradient">q_vertical_gradient</a>)
3593are assumed as initial profiles. The subgrid-scale TKE is set to 0 but K<sub>m</sub>
3594and K<sub>h</sub> are set to very small values because
3595otherwise no TKE
3596would be generated.</p>
3597
3598
3599
3600 
3601     
3602     
3603     
3604      </ul>
3605
3606
3607
3608 
3609     
3610     
3611     
3612      <p style="font-style: italic;">'set_1d-model_profiles' </p>
3613
3614
3615
3616
3617     
3618     
3619     
3620      <ul>
3621
3622
3623
3624 
3625       
3626       
3627       
3628        <p>The arrays of the 3d-model are initialized with
3629the
3630(stationary) solution of the 1d-model. These are the variables e, kh,
3631km, u, v and with Prandtl layer switched on rif, us, usws, vsws. The
3632temperature (humidity) profile consisting of linear sections is set as
3633for 'set_constant_profiles' and assumed as constant in time within the
36341d-model. For steering of the 1d-model a set of parameters with suffix
3635"_1d" (e.g. <a href="#end_time_1d">end_time_1d</a>,
3636        <a href="#damp_level_1d">damp_level_1d</a>)
3637is available.</p>
3638
3639
3640
3641 
3642     
3643     
3644     
3645      </ul>
3646
3647
3648
3649 
3650     
3651     
3652     
3653      <p><span style="font-style: italic;">'by_user'</span></p>
3654
3655
3656
3657     
3658     
3659     
3660      <p style="margin-left: 40px;">The initialization of the arrays
3661of the 3d-model is under complete control of the user and has to be
3662done in routine <a href="chapter_3.5.1.html#user_init_3d_model">user_init_3d_model</a>
3663of the user-interface.<span style="font-style: italic;"></span></p>
3664
3665
3666
3667     
3668     
3669     
3670      <p><span style="font-style: italic;">'initialize_vortex'</span>
3671      </p>
3672
3673
3674
3675 
3676     
3677     
3678     
3679      <div style="margin-left: 40px;">The initial
3680velocity field of the
36813d-model corresponds to a
3682Rankine-vortex with vertical axis. This setting may be used to test
3683advection 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>)
3684are necessary. In order not to distort the vortex, an initial
3685horizontal wind profile constant
3686with height is necessary (to be set by <b>initializing_actions</b>
3687= <span style="font-style: italic;">'set_constant_profiles'</span>)
3688and some other conditions have to be met (neutral stratification,
3689diffusion must be
3690switched off, see <a href="#km_constant">km_constant</a>).
3691The center of the vortex is located at jc = (nx+1)/2. It
3692extends from k = 0 to k = nz+1. Its radius is 8 * <a href="#dx">dx</a>
3693and the exponentially decaying part ranges to 32 * <a href="#dx">dx</a>
3694(see init_rankine.f90). </div>
3695
3696
3697
3698 
3699     
3700     
3701     
3702      <p><span style="font-style: italic;">'initialize_ptanom'</span>
3703      </p>
3704
3705
3706
3707 
3708     
3709     
3710     
3711      <ul>
3712
3713
3714
3715 
3716       
3717       
3718       
3719        <p>A 2d-Gauss-like shape disturbance
3720(x,y) is added to the
3721initial temperature field with radius 10.0 * <a href="#dx">dx</a>
3722and center at jc = (nx+1)/2. This may be used for tests of scalar
3723advection schemes
3724(see <a href="#scalar_advec">scalar_advec</a>).
3725Such tests require a horizontal wind profile constant with hight and
3726diffusion
3727switched off (see <span style="font-style: italic;">'initialize_vortex'</span>).
3728Additionally, the buoyancy term
3729must be switched of in the equation of motion&nbsp; for w (this
3730requires the user to comment out the call of <span style="font-family: monospace;">buoyancy</span> in the
3731source code of <span style="font-family: monospace;">prognostic_equations.f90</span>).</p>
3732
3733
3734
3735
3736     
3737     
3738     
3739      </ul>
3740
3741
3742
3743 
3744     
3745     
3746     
3747      <p style="font-style: normal;">Values may be
3748combined, e.g. <b>initializing_actions</b> = <span style="font-style: italic;">'set_constant_profiles
3749initialize_vortex'</span>, but the values of <span style="font-style: italic;">'set_constant_profiles'</span>,
3750      <span style="font-style: italic;">'set_1d-model_profiles'</span>
3751, and <span style="font-style: italic;">'by_user'</span>
3752must not be given at the same time.</p>
3753
3754
3755
3756 
3757     
3758     
3759     
3760      <p style="font-style: italic;"> </p>
3761
3762
3763
3764 </td>
3765
3766
3767
3768 </tr>
3769
3770
3771
3772
3773    <tr>
3774
3775
3776
3777 <td style="vertical-align: top;"> 
3778     
3779     
3780     
3781      <p><a name="km_constant"></a><b>km_constant</b></p>
3782
3783
3784
3785
3786      </td>
3787
3788
3789
3790 <td style="vertical-align: top;">R</td>
3791
3792
3793
3794
3795      <td style="vertical-align: top;"><i>variable<br>
3796
3797
3798
3799
3800(computed from TKE)</i></td>
3801
3802
3803
3804 <td style="vertical-align: top;"> 
3805     
3806     
3807     
3808      <p>Constant eddy
3809diffusivities are used (laminar
3810simulations).&nbsp; </p>
3811
3812
3813
3814 
3815     
3816     
3817     
3818      <p>If this parameter is
3819specified, both in the 1d and in the
38203d-model constant values for the eddy diffusivities are used in
3821space and time with K<sub>m</sub> = <b>km_constant</b>
3822and K<sub>h</sub> = K<sub>m</sub> / <a href="chapter_4.2.html#prandtl_number">prandtl_number</a>.
3823The prognostic equation for the subgrid-scale TKE is switched off.
3824Constant eddy diffusivities are only allowed with the Prandtl layer (<a href="#prandtl_layer">prandtl_layer</a>)
3825switched off.</p>
3826
3827
3828
3829 </td>
3830
3831
3832
3833 </tr>
3834
3835
3836
3837 <tr>
3838
3839
3840
3841 <td style="vertical-align: top;"> 
3842     
3843     
3844     
3845      <p><a name="km_damp_max"></a><b>km_damp_max</b></p>
3846
3847
3848
3849
3850      </td>
3851
3852
3853
3854 <td style="vertical-align: top;">R</td>
3855
3856
3857
3858
3859      <td style="vertical-align: top;"><span style="font-style: italic;">0.5*(dx
3860or dy)</span></td>
3861
3862
3863
3864 <td style="vertical-align: top;">Maximum
3865diffusivity used for filtering the velocity field in the vicinity of
3866the outflow (in m<sup>2</sup>/s).<br>
3867
3868
3869
3870 <br>
3871
3872
3873
3874
3875When using non-cyclic lateral boundaries (see <a href="#bc_lr">bc_lr</a>
3876or <a href="#bc_ns">bc_ns</a>),
3877a smoothing has to be applied to the
3878velocity field in the vicinity of the outflow in order to suppress any
3879reflections of outgoing disturbances. Smoothing is done by increasing
3880the eddy diffusivity along the horizontal direction which is
3881perpendicular to the outflow boundary. Only velocity components
3882parallel to the outflow boundary are filtered (e.g. v and w, if the
3883outflow is along x). Damping is applied from the bottom to the top of
3884the domain.<br>
3885
3886
3887
3888 <br>
3889
3890
3891
3892
3893The horizontal range of the smoothing is controlled by <a href="#outflow_damping_width">outflow_damping_width</a>
3894which defines the number of gridpoints (counted from the outflow
3895boundary) from where on the smoothing is applied. Starting from that
3896point, the eddy diffusivity is linearly increased (from zero to its
3897maximum value given by <span style="font-weight: bold;">km_damp_max</span>)
3898until half of the damping range width, from where it remains constant
3899up to the outflow boundary. If at a certain grid point the eddy
3900diffusivity calculated from the flow field is larger than as described
3901above, it is used instead.<br>
3902
3903
3904
3905 <br>
3906
3907
3908
3909
3910The default value of <span style="font-weight: bold;">km_damp_max</span>
3911has been empirically proven to be sufficient.</td>
3912
3913
3914
3915 </tr>
3916
3917
3918
3919 <tr>
3920
3921
3922
3923
3924      <td style="vertical-align: top;"> 
3925     
3926     
3927     
3928      <p><a name="long_filter_factor"></a><b>long_filter_factor</b></p>
3929
3930
3931
3932
3933      </td>
3934
3935
3936
3937 <td style="vertical-align: top;">R</td>
3938
3939
3940
3941
3942      <td style="vertical-align: top;"><i>0.0</i></td>
3943
3944
3945
3946
3947      <td style="vertical-align: top;"> 
3948     
3949     
3950     
3951      <p>Filter factor
3952for the so-called Long-filter.<br>
3953
3954
3955
3956 </p>
3957
3958
3959
3960 
3961     
3962     
3963     
3964      <p><br>
3965
3966
3967
3968
3969This filter very efficiently
3970eliminates 2-delta-waves sometimes cauesed by the upstream-spline
3971scheme (see Mahrer and
3972Pielke, 1978: Mon. Wea. Rev., 106, 818-830). It works in all three
3973directions in space. A value of <b>long_filter_factor</b>
3974= <i>0.01</i>
3975sufficiently removes the small-scale waves without affecting the
3976longer waves.<br>
3977
3978
3979
3980 </p>
3981
3982
3983
3984 
3985     
3986     
3987     
3988      <p>By default, the filter is
3989switched off (= <i>0.0</i>).
3990It is exclusively applied to the tendencies calculated by the
3991upstream-spline scheme (see <a href="#momentum_advec">momentum_advec</a>
3992and <a href="#scalar_advec">scalar_advec</a>),
3993not to the prognostic variables themselves. At the bottom and top
3994boundary of the model domain the filter effect for vertical
39952-delta-waves is reduced. There, the amplitude of these waves is only
3996reduced by approx. 50%, otherwise by nearly 100%.&nbsp; <br>
3997
3998
3999
4000
4001Filter factors with values &gt; <i>0.01</i> also
4002reduce the amplitudes
4003of waves with wavelengths longer than 2-delta (see the paper by Mahrer
4004and
4005Pielke, quoted above). </p>
4006
4007
4008
4009 </td>
4010
4011
4012
4013 </tr>
4014
4015
4016
4017 <tr>
4018
4019
4020
4021      <td style="vertical-align: top;"><a name="loop_optimization"></a><span style="font-weight: bold;">loop_optimization</span></td>
4022
4023
4024
4025      <td style="vertical-align: top;">C*16</td>
4026
4027
4028
4029      <td style="vertical-align: top;"><span style="font-style: italic;">see right</span></td>
4030
4031
4032
4033      <td>Method used to optimize loops for solving the prognostic equations .<br>
4034
4035
4036
4037      <br>
4038
4039
4040
4041By
4042default, the optimization method depends on the host on which PALM is
4043running. On machines with vector-type CPUs, single 3d-loops are used to
4044calculate each tendency term of each prognostic equation, while on all
4045other machines, all prognostic equations are solved within one big loop
4046over 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>
4047
4048
4049
4050      <br>
4051
4052
4053
4054The 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>
4055
4056
4057
4058    </tr>
4059
4060
4061
4062    <tr>
4063
4064
4065
4066
4067      <td style="vertical-align: top;"><a name="mixing_length_1d"></a><span style="font-weight: bold;">mixing_length_1d</span><br>
4068
4069
4070
4071
4072      </td>
4073
4074
4075
4076 <td style="vertical-align: top;">C*20<br>
4077
4078
4079
4080
4081      </td>
4082
4083
4084
4085 <td style="vertical-align: top;"><span style="font-style: italic;">'as_in_3d_</span><br style="font-style: italic;">
4086
4087
4088
4089 <span style="font-style: italic;">model'</span><br>
4090
4091
4092
4093 </td>
4094
4095
4096
4097
4098      <td style="vertical-align: top;">Mixing length used in the
40991d-model.<br>
4100
4101
4102
4103 <br>
4104
4105
4106
4107
4108By default the mixing length is calculated as in the 3d-model (i.e. it
4109depends on the grid spacing).<br>
4110
4111
4112
4113 <br>
4114
4115
4116
4117
4118By setting <span style="font-weight: bold;">mixing_length_1d</span>
4119= <span style="font-style: italic;">'blackadar'</span>,
4120the so-called Blackadar mixing length is used (l = kappa * z / ( 1 +
4121kappa * z / lambda ) with the limiting value lambda = 2.7E-4 * u_g / f).<br>
4122
4123
4124
4125
4126      </td>
4127
4128
4129
4130 </tr>
4131
4132
4133
4134 <tr>
4135
4136
4137
4138 <td style="vertical-align: top;"> 
4139     
4140     
4141     
4142      <p><a name="humidity"></a><b>humidity</b></p>
4143
4144
4145
4146
4147      </td>
4148
4149
4150
4151 <td style="vertical-align: top;">L</td>
4152
4153
4154
4155
4156      <td style="vertical-align: top;"><i>.F.</i></td>
4157
4158
4159
4160
4161      <td style="vertical-align: top;"> 
4162     
4163     
4164     
4165      <p>Parameter to
4166switch on the prognostic equation for specific
4167humidity q.<br>
4168
4169
4170
4171 </p>
4172
4173
4174
4175 
4176     
4177     
4178     
4179      <p>The initial vertical
4180profile 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>
4181and <a href="chapter_4.1.html#q_vertical_gradient_level">q_vertical_gradient_level</a>.&nbsp;
4182Boundary conditions can be set via <a href="chapter_4.1.html#q_surface_initial_change">q_surface_initial_change</a>
4183and <a href="chapter_4.1.html#surface_waterflux">surface_waterflux</a>.<br>
4184
4185
4186
4187
4188      </p>
4189
4190
4191
4192
4193If the condensation scheme is switched on (<a href="chapter_4.1.html#cloud_physics">cloud_physics</a>
4194= .TRUE.), q becomes the total liquid water content (sum of specific
4195humidity and liquid water content).</td>
4196
4197
4198
4199 </tr>
4200
4201
4202
4203
4204    <tr>
4205
4206
4207
4208 <td style="vertical-align: top;"> 
4209     
4210     
4211     
4212      <p><a name="momentum_advec"></a><b>momentum_advec</b></p>
4213
4214
4215
4216
4217      </td>
4218
4219
4220
4221 <td style="vertical-align: top;">C * 10</td>
4222
4223
4224
4225
4226      <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
4227
4228
4229
4230
4231      <td style="vertical-align: top;"> 
4232     
4233     
4234     
4235      <p>Advection
4236scheme to be used for the momentum equations.<br>
4237
4238
4239
4240 <br>
4241
4242
4243
4244
4245The user can choose between the following schemes:<br>
4246
4247
4248
4249
4250&nbsp;<br>
4251
4252
4253
4254 <br>
4255
4256
4257
4258 <span style="font-style: italic;">'pw-scheme'</span><br>
4259
4260
4261
4262
4263      </p>
4264
4265
4266
4267 
4268     
4269     
4270     
4271      <div style="margin-left: 40px;">The scheme of
4272Piascek and
4273Williams (1970, J. Comp. Phys., 6,
4274392-405) with central differences in the form C3 is used.<br>
4275
4276
4277
4278
4279If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
4280= <span style="font-style: italic;">'leapfrog+euler'</span>
4281the
4282advection scheme is - for the Euler-timestep - automatically switched
4283to an upstream-scheme.<br>
4284
4285
4286
4287 </div>
4288
4289
4290
4291 
4292     
4293     
4294     
4295      <p> </p>
4296
4297
4298
4299 
4300     
4301     
4302     
4303      <p><span style="font-style: italic;">'ups-scheme'</span><br>
4304
4305
4306
4307
4308      </p>
4309
4310
4311
4312 
4313     
4314     
4315     
4316      <div style="margin-left: 40px;">The
4317upstream-spline scheme is
4318used
4319(see Mahrer and Pielke,
43201978: Mon. Wea. Rev., 106, 818-830). In opposite to the
4321Piascek-Williams scheme, this is characterized by much better numerical
4322features (less numerical diffusion, better preservation of flow
4323structures, e.g. vortices), but computationally it is much more
4324expensive. In
4325addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
4326= <span style="font-style: italic;">'</span><i>euler'</i>),
4327i.e. the
4328timestep accuracy is only of first order.
4329For this reason the advection of scalar variables (see <a href="#scalar_advec">scalar_advec</a>)
4330should then also be carried out with the upstream-spline scheme,
4331because otherwise the scalar variables would
4332be subject to large numerical diffusion due to the upstream
4333scheme.&nbsp; </div>
4334
4335
4336
4337 
4338     
4339     
4340     
4341      <p style="margin-left: 40px;">Since
4342the cubic splines used tend
4343to overshoot under
4344certain circumstances, this effect must be adjusted by suitable
4345filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
4346      <a href="#long_filter_factor">long_filter_factor</a>,
4347      <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>).
4348This is always neccessary for runs with stable stratification,
4349even if this stratification appears only in parts of the model domain.<br>
4350
4351
4352
4353
4354      </p>
4355
4356
4357
4358 
4359     
4360     
4361     
4362      <div style="margin-left: 40px;">With stable
4363stratification the
4364upstream-spline scheme also
4365produces gravity waves with large amplitude, which must be
4366suitably damped (see <a href="chapter_4.2.html#rayleigh_damping_factor">rayleigh_damping_factor</a>).<br>
4367
4368
4369
4370
4371      <br>
4372
4373
4374
4375 <span style="font-weight: bold;">Important: </span>The&nbsp;
4376upstream-spline scheme is not implemented for humidity and passive
4377scalars (see&nbsp;<a href="#humidity">humidity</a>
4378and <a href="#passive_scalar">passive_scalar</a>)
4379and requires the use of a 2d-domain-decomposition. The last conditions
4380severely restricts code optimization on several machines leading to
4381very long execution times! The scheme is also not allowed for
4382non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
4383and <a href="#bc_ns">bc_ns</a>).</div>
4384
4385
4386
4387 </td>
4388
4389
4390
4391
4392    </tr>
4393
4394
4395
4396 <tr>
4397
4398
4399
4400 <td style="vertical-align: top;"><a name="netcdf_precision"></a><span style="font-weight: bold;">netcdf_precision</span><br>
4401
4402
4403
4404
4405      </td>
4406
4407
4408
4409 <td style="vertical-align: top;">C*20<br>
4410
4411
4412
4413
4414(10)<br>
4415
4416
4417
4418 </td>
4419
4420
4421
4422 <td style="vertical-align: top;"><span style="font-style: italic;">single preci-</span><br style="font-style: italic;">
4423
4424
4425
4426 <span style="font-style: italic;">sion for all</span><br style="font-style: italic;">
4427
4428
4429
4430 <span style="font-style: italic;">output quan-</span><br style="font-style: italic;">
4431
4432
4433
4434 <span style="font-style: italic;">tities</span><br>
4435
4436
4437
4438 </td>
4439
4440
4441
4442
4443      <td style="vertical-align: top;">Defines the accuracy of
4444the NetCDF output.<br>
4445
4446
4447
4448 <br>
4449
4450
4451
4452
4453By default, all NetCDF output data (see <a href="chapter_4.2.html#data_output_format">data_output_format</a>)
4454have single precision&nbsp; (4 byte) accuracy. Double precision (8
4455byte) can be choosen alternatively.<br>
4456
4457
4458
4459
4460Accuracy for the different output data (cross sections, 3d-volume data,
4461spectra, etc.) can be set independently.<br>
4462
4463
4464
4465 <span style="font-style: italic;">'&lt;out&gt;_NF90_REAL4'</span>
4466(single precision) or <span style="font-style: italic;">'&lt;out&gt;_NF90_REAL8'</span>
4467(double precision) are the two principally allowed values for <span style="font-weight: bold;">netcdf_precision</span>,
4468where the string <span style="font-style: italic;">'&lt;out&gt;'
4469      </span>can be chosen out of the following list:<br>
4470
4471
4472
4473 <br>
4474
4475
4476
4477
4478     
4479     
4480     
4481      <table style="text-align: left; width: 284px; height: 234px;" border="1" cellpadding="2" cellspacing="2">
4482
4483
4484
4485 <tbody>
4486
4487
4488
4489
4490          <tr>
4491
4492
4493
4494 <td style="vertical-align: top;"><span style="font-style: italic;">'xy'</span><br>
4495
4496
4497
4498 </td>
4499
4500
4501
4502
4503            <td style="vertical-align: top;">horizontal cross section<br>
4504
4505
4506
4507
4508            </td>
4509
4510
4511
4512 </tr>
4513
4514
4515
4516 <tr>
4517
4518
4519
4520 <td style="vertical-align: top;"><span style="font-style: italic;">'xz'</span><br>
4521
4522
4523
4524 </td>
4525
4526
4527
4528
4529            <td style="vertical-align: top;">vertical (xz) cross
4530section<br>
4531
4532
4533
4534 </td>
4535
4536
4537
4538 </tr>
4539
4540
4541
4542 <tr>
4543
4544
4545
4546 <td style="vertical-align: top;"><span style="font-style: italic;">'yz'</span><br>
4547
4548
4549
4550 </td>
4551
4552
4553
4554
4555            <td style="vertical-align: top;">vertical (yz) cross
4556section<br>
4557
4558
4559
4560 </td>
4561
4562
4563
4564 </tr>
4565
4566
4567
4568 <tr>
4569
4570
4571
4572 <td style="vertical-align: top;"><span style="font-style: italic;">'2d'</span><br>
4573
4574
4575
4576 </td>
4577
4578
4579
4580
4581            <td style="vertical-align: top;">all cross sections<br>
4582
4583
4584
4585
4586            </td>
4587
4588
4589
4590 </tr>
4591
4592
4593
4594 <tr>
4595
4596
4597
4598 <td style="vertical-align: top;"><span style="font-style: italic;">'3d'</span><br>
4599
4600
4601
4602 </td>
4603
4604
4605
4606
4607            <td style="vertical-align: top;">volume data<br>
4608
4609
4610
4611 </td>
4612
4613
4614
4615
4616          </tr>
4617
4618
4619
4620 <tr>
4621
4622
4623
4624 <td style="vertical-align: top;"><span style="font-style: italic;">'pr'</span><br>
4625
4626
4627
4628 </td>
4629
4630
4631
4632
4633            <td style="vertical-align: top;">vertical profiles<br>
4634
4635
4636
4637
4638            </td>
4639
4640
4641
4642 </tr>
4643
4644
4645
4646 <tr>
4647
4648
4649
4650 <td style="vertical-align: top;"><span style="font-style: italic;">'ts'</span><br>
4651
4652
4653
4654 </td>
4655
4656
4657
4658
4659            <td style="vertical-align: top;">time series, particle
4660time series<br>
4661
4662
4663
4664 </td>
4665
4666
4667
4668 </tr>
4669
4670
4671
4672 <tr>
4673
4674
4675
4676 <td style="vertical-align: top;"><span style="font-style: italic;">'sp'</span><br>
4677
4678
4679
4680 </td>
4681
4682
4683
4684
4685            <td style="vertical-align: top;">spectra<br>
4686
4687
4688
4689 </td>
4690
4691
4692
4693
4694          </tr>
4695
4696
4697
4698 <tr>
4699
4700
4701
4702 <td style="vertical-align: top;"><span style="font-style: italic;">'prt'</span><br>
4703
4704
4705
4706 </td>
4707
4708
4709
4710
4711            <td style="vertical-align: top;">particles<br>
4712
4713
4714
4715 </td>
4716
4717
4718
4719
4720          </tr>
4721
4722
4723
4724 <tr>
4725
4726
4727
4728 <td style="vertical-align: top;"><span style="font-style: italic;">'all'</span><br>
4729
4730
4731
4732 </td>
4733
4734
4735
4736
4737            <td style="vertical-align: top;">all output quantities<br>
4738
4739
4740
4741
4742            </td>
4743
4744
4745
4746 </tr>
4747
4748
4749
4750 
4751       
4752       
4753       
4754        </tbody> 
4755     
4756     
4757     
4758      </table>
4759
4760
4761
4762 <br>
4763
4764
4765
4766 <span style="font-weight: bold;">Example:</span><br>
4767
4768
4769
4770
4771If all cross section data and the particle data shall be output in
4772double 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>
4773has to be assigned.<br>
4774
4775
4776
4777 </td>
4778
4779
4780
4781 </tr>
4782
4783
4784
4785
4786    <tr>
4787
4788
4789
4790 <td style="vertical-align: top;"> 
4791     
4792     
4793     
4794      <p><a name="npex"></a><b>npex</b></p>
4795
4796
4797
4798 </td>
4799
4800
4801
4802
4803      <td style="vertical-align: top;">I</td>
4804
4805
4806
4807 <td style="vertical-align: top;"><br>
4808
4809
4810
4811 </td>
4812
4813
4814
4815 <td style="vertical-align: top;"> 
4816     
4817     
4818     
4819      <p>Number of processors
4820along x-direction of the virtual
4821processor
4822net.&nbsp; </p>
4823
4824
4825
4826 
4827     
4828     
4829     
4830      <p>For parallel runs, the total
4831number of processors to be used
4832is given by
4833the <span style="font-weight: bold;">mrun</span>
4834option <a href="http://www.muk.uni-hannover.de/software/mrun_beschreibung.html#Opt-X">-X</a>.
4835By default, depending on the type of the parallel computer, PALM
4836generates a 1d processor
4837net (domain decomposition along x, <span style="font-weight: bold;">npey</span>
4838= <span style="font-style: italic;">1</span>) or a
48392d-net (this is
4840favored on machines with fast communication network). In case of a
48412d-net, it is tried to make it more or less square-shaped. If, for
4842example, 16 processors are assigned (-X 16), a 4 * 4 processor net is
4843generated (<span style="font-weight: bold;">npex</span>
4844= <span style="font-style: italic;">4</span>, <span style="font-weight: bold;">npey</span>
4845= <span style="font-style: italic;">4</span>).
4846This choice is optimal for square total domains (<a href="#nx">nx</a>
4847= <a href="#ny">ny</a>),
4848since then the number of ghost points at the lateral boundarys of
4849the subdomains is minimal. If <span style="font-weight: bold;">nx</span>
4850nd <span style="font-weight: bold;">ny</span>
4851differ extremely, the
4852processor 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>
4853
4854
4855
4856
4857     
4858     
4859     
4860      <p><b>Important:</b> The value of <span style="font-weight: bold;">npex</span> * <span style="font-weight: bold;">npey</span> must exactly
4861correspond to the
4862value assigned by the <span style="font-weight: bold;">mrun</span>-option
4863      <tt>-X</tt>.
4864Otherwise the model run will abort with a corresponding error
4865message.&nbsp; <br>
4866
4867
4868
4869
4870Additionally, the specification of <span style="font-weight: bold;">npex</span>
4871and <span style="font-weight: bold;">npey</span>
4872may of course
4873override the default setting for the domain decomposition (1d or 2d)
4874which may have a significant (negative) effect on the code performance.
4875      </p>
4876
4877
4878
4879 </td>
4880
4881
4882
4883 </tr>
4884
4885
4886
4887 <tr>
4888
4889
4890
4891 <td style="vertical-align: top;"> 
4892     
4893     
4894     
4895      <p><a name="npey"></a><b>npey</b></p>
4896
4897
4898
4899
4900      </td>
4901
4902
4903
4904 <td style="vertical-align: top;">I</td>
4905
4906
4907
4908
4909      <td style="vertical-align: top;"><br>
4910
4911
4912
4913 </td>
4914
4915
4916
4917 <td style="vertical-align: top;"> 
4918     
4919     
4920     
4921      <p>Number of processors
4922along y-direction of the virtual
4923processor
4924net.&nbsp; </p>
4925
4926
4927
4928 
4929     
4930     
4931     
4932      <p>For further information see <a href="#npex">npex</a>.</p>
4933
4934
4935
4936 </td>
4937
4938
4939
4940 </tr>
4941
4942
4943
4944
4945    <tr>
4946
4947
4948
4949 <td style="vertical-align: top;"> 
4950     
4951     
4952     
4953      <p><a name="nsor_ini"></a><b>nsor_ini</b></p>
4954
4955
4956
4957
4958      </td>
4959
4960
4961
4962 <td style="vertical-align: top;">I</td>
4963
4964
4965
4966
4967      <td style="vertical-align: top;"><i>100</i></td>
4968
4969
4970
4971
4972      <td style="vertical-align: top;"> 
4973     
4974     
4975     
4976      <p>Initial number
4977of iterations with the SOR algorithm.&nbsp; </p>
4978
4979
4980
4981 
4982     
4983     
4984     
4985      <p>This
4986parameter is only effective if the SOR algorithm was
4987selected as the pressure solver scheme (<a href="chapter_4.2.html#psolver">psolver</a>
4988= <span style="font-style: italic;">'sor'</span>)
4989and specifies the
4990number of initial iterations of the SOR
4991scheme (at t = 0). The number of subsequent iterations at the following
4992timesteps is determined
4993with the parameter <a href="#nsor">nsor</a>.
4994Usually <b>nsor</b> &lt; <b>nsor_ini</b>,
4995since in each case
4996subsequent calls to <a href="chapter_4.2.html#psolver">psolver</a>
4997use the solution of the previous call as initial value. Suitable
4998test runs should determine whether sufficient convergence of the
4999solution is obtained with the default value and if necessary the value
5000of <b>nsor_ini</b> should be changed.</p>
5001
5002
5003
5004 </td>
5005
5006
5007
5008
5009    </tr>
5010
5011
5012
5013 <tr>
5014
5015
5016
5017 <td style="vertical-align: top;">
5018     
5019     
5020     
5021      <p><a name="nx"></a><b>nx</b></p>
5022
5023
5024
5025
5026      </td>
5027
5028
5029
5030 <td style="vertical-align: top;">I</td>
5031
5032
5033
5034
5035      <td style="vertical-align: top;"><br>
5036
5037
5038
5039 </td>
5040
5041
5042
5043 <td style="vertical-align: top;"> 
5044     
5045     
5046     
5047      <p>Number of grid
5048points in x-direction.&nbsp; </p>
5049
5050
5051
5052 
5053     
5054     
5055     
5056      <p>A value for this
5057parameter must be assigned. Since the lower
5058array bound in PALM
5059starts with i = 0, the actual number of grid points is equal to <b>nx+1</b>.
5060In case of cyclic boundary conditions along x, the domain size is (<b>nx+1</b>)*
5061      <a href="#dx">dx</a>.</p>
5062
5063
5064
5065 
5066     
5067     
5068     
5069      <p>For
5070parallel runs, in case of <a href="#grid_matching">grid_matching</a>
5071= <span style="font-style: italic;">'strict'</span>,
5072      <b>nx+1</b> must
5073be an integral multiple
5074of the processor numbers (see <a href="#npex">npex</a>
5075and <a href="#npey">npey</a>)
5076along x- as well as along y-direction (due to data
5077transposition restrictions).</p>
5078
5079
5080
5081     
5082     
5083     
5084      <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>
5085and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
5086
5087
5088
5089 </td>
5090
5091
5092
5093 </tr>
5094
5095
5096
5097 <tr>
5098
5099
5100
5101
5102      <td style="vertical-align: top;"> 
5103     
5104     
5105     
5106      <p><a name="ny"></a><b>ny</b></p>
5107
5108
5109
5110
5111      </td>
5112
5113
5114
5115 <td style="vertical-align: top;">I</td>
5116
5117
5118
5119
5120      <td style="vertical-align: top;"><br>
5121
5122
5123
5124 </td>
5125
5126
5127
5128 <td style="vertical-align: top;"> 
5129     
5130     
5131     
5132      <p>Number of grid
5133points in y-direction.&nbsp; </p>
5134
5135
5136
5137 
5138     
5139     
5140     
5141      <p>A value for this
5142parameter must be assigned. Since the lower
5143array bound in PALM starts with i = 0, the actual number of grid points
5144is equal to <b>ny+1</b>. In case of cyclic boundary
5145conditions along
5146y, the domain size is (<b>ny+1</b>) * <a href="#dy">dy</a>.</p>
5147
5148
5149
5150
5151     
5152     
5153     
5154      <p>For parallel runs, in case of <a href="#grid_matching">grid_matching</a>
5155= <span style="font-style: italic;">'strict'</span>,
5156      <b>ny+1</b> must
5157be an integral multiple
5158of the processor numbers (see <a href="#npex">npex</a>
5159and <a href="#npey">npey</a>)&nbsp;
5160along y- as well as along x-direction (due to data
5161transposition restrictions).</p>
5162
5163
5164
5165     
5166     
5167     
5168      <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>
5169and&nbsp;<a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a>.</p>
5170
5171
5172
5173 </td>
5174
5175
5176
5177 </tr>
5178
5179
5180
5181 <tr>
5182
5183
5184
5185
5186      <td style="vertical-align: top;"> 
5187     
5188     
5189     
5190      <p><a name="nz"></a><b>nz</b></p>
5191
5192
5193
5194
5195      </td>
5196
5197
5198
5199 <td style="vertical-align: top;">I</td>
5200
5201
5202
5203
5204      <td style="vertical-align: top;"><br>
5205
5206
5207
5208 </td>
5209
5210
5211
5212 <td style="vertical-align: top;"> 
5213     
5214     
5215     
5216      <p>Number of grid
5217points in z-direction.&nbsp; </p>
5218
5219
5220
5221 
5222     
5223     
5224     
5225      <p>A value for this
5226parameter must be assigned. Since the lower
5227array bound in PALM
5228starts with k = 0 and since one additional grid point is added at the
5229top boundary (k = <b>nz+1</b>), the actual number of grid
5230points is <b>nz+2</b>.
5231However, the prognostic equations are only solved up to <b>nz</b>
5232(u,
5233v)
5234or up to <b>nz-1</b> (w, scalar quantities). The top
5235boundary for u
5236and v is at k = <b>nz+1</b> (u, v) while at k = <b>nz</b>
5237for all
5238other quantities.&nbsp; </p>
5239
5240
5241
5242 
5243     
5244     
5245     
5246      <p>For parallel
5247runs,&nbsp; in case of <a href="#grid_matching">grid_matching</a>
5248= <span style="font-style: italic;">'strict'</span>,
5249      <b>nz</b> must
5250be an integral multiple of
5251the number of processors in x-direction (due to data transposition
5252restrictions).</p>
5253
5254
5255
5256 </td>
5257
5258
5259
5260 </tr>
5261
5262
5263
5264 <tr>
5265
5266
5267
5268      <td style="vertical-align: top;"><a name="ocean"></a><span style="font-weight: bold;">ocean</span></td>
5269
5270
5271
5272      <td style="vertical-align: top;">L</td>
5273
5274
5275
5276      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
5277
5278
5279
5280      <td style="vertical-align: top;">Parameter to switch on&nbsp;ocean runs.<br>
5281
5282
5283
5284      <br>
5285
5286
5287
5288By 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>
5289
5290
5291
5292      <br>
5293
5294
5295
5296     
5297     
5298     
5299      <ul>
5300
5301
5302
5303        <li>An additional prognostic equation for salinity is solved.</li>
5304
5305
5306
5307        <li>Potential temperature in buoyancy and stability-related terms is replaced by potential density.</li>
5308
5309
5310
5311        <li>Potential
5312density is calculated from the equation of state for seawater after
5313each timestep, using the algorithm proposed by Jackett et al. (2006, J.
5314Atmos. Oceanic Technol., <span style="font-weight: bold;">23</span>, 1709-1728).<br>
5315
5316
5317
5318So far, only the initial hydrostatic pressure is entered into this equation.</li>
5319
5320
5321
5322        <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>
5323
5324
5325
5326        <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>
5327
5328
5329
5330        <li>Zero salinity flux is used as default boundary condition at the bottom of the sea.</li>
5331
5332
5333
5334        <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>
5335
5336
5337
5338     
5339     
5340     
5341      </ul>
5342
5343
5344
5345      <br>
5346
5347
5348
5349Relevant 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>
5350
5351
5352
5353      <br>
5354
5355
5356
5357Section <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>
5358
5359
5360
5361      <br>
5362
5363
5364
5365      <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>
5366      </td>
5367
5368
5369
5370    </tr>
5371
5372
5373
5374    <tr>
5375
5376
5377
5378 <td style="vertical-align: top;"> 
5379     
5380     
5381     
5382      <p><a name="omega"></a><b>omega</b></p>
5383
5384
5385
5386
5387      </td>
5388
5389
5390
5391 <td style="vertical-align: top;">R</td>
5392
5393
5394
5395
5396      <td style="vertical-align: top;"><i>7.29212E-5</i></td>
5397
5398
5399
5400
5401      <td style="vertical-align: top;"> 
5402     
5403     
5404     
5405      <p>Angular
5406velocity of the rotating system (in rad s<sup>-1</sup>).&nbsp;
5407      </p>
5408
5409
5410
5411 
5412     
5413     
5414     
5415      <p>The angular velocity of the earth is set by
5416default. The
5417values
5418of the Coriolis parameters are calculated as:&nbsp; </p>
5419
5420
5421
5422 
5423     
5424     
5425     
5426      <ul>
5427
5428
5429
5430
5431       
5432       
5433       
5434        <p>f = 2.0 * <b>omega</b> * sin(<a href="#phi">phi</a>)&nbsp;
5435        <br>
5436
5437
5438
5439f* = 2.0 * <b>omega</b> * cos(<a href="#phi">phi</a>)</p>
5440
5441
5442
5443
5444     
5445     
5446     
5447      </ul>
5448
5449
5450
5451 </td>
5452
5453
5454
5455 </tr>
5456
5457
5458
5459 <tr>
5460
5461
5462
5463 <td style="vertical-align: top;"> 
5464     
5465     
5466     
5467      <p><a name="outflow_damping_width"></a><b>outflow_damping_width</b></p>
5468
5469
5470
5471
5472      </td>
5473
5474
5475
5476 <td style="vertical-align: top;">I</td>
5477
5478
5479
5480
5481      <td style="vertical-align: top;"><span style="font-style: italic;">MIN(20,
5482nx/2</span> or <span style="font-style: italic;">ny/2)</span></td>
5483
5484
5485
5486
5487      <td style="vertical-align: top;">Width of
5488the damping range in the vicinity of the outflow (gridpoints).<br>
5489
5490
5491
5492
5493      <br>
5494
5495
5496
5497
5498When using non-cyclic lateral boundaries (see <a href="chapter_4.1.html#bc_lr">bc_lr</a>
5499or <a href="chapter_4.1.html#bc_ns">bc_ns</a>),
5500a smoothing has to be applied to the
5501velocity field in the vicinity of the outflow in order to suppress any
5502reflections of outgoing disturbances. This parameter controlls the
5503horizontal range to which the smoothing is applied. The range is given
5504in gridpoints counted from the respective outflow boundary. For further
5505details about the smoothing see parameter <a href="chapter_4.1.html#km_damp_max">km_damp_max</a>,
5506which defines the magnitude of the damping.</td>
5507
5508
5509
5510 </tr>
5511
5512
5513
5514
5515    <tr>
5516
5517
5518
5519 <td style="vertical-align: top;"> 
5520     
5521     
5522     
5523      <p><a name="overshoot_limit_e"></a><b>overshoot_limit_e</b></p>
5524
5525
5526
5527
5528      </td>
5529
5530
5531
5532 <td style="vertical-align: top;">R</td>
5533
5534
5535
5536
5537      <td style="vertical-align: top;"><i>0.0</i></td>
5538
5539
5540
5541
5542      <td style="vertical-align: top;"> 
5543     
5544     
5545     
5546      <p>Allowed limit
5547for the overshooting of subgrid-scale TKE in
5548case that the upstream-spline scheme is switched on (in m<sup>2</sup>/s<sup>2</sup>).&nbsp;
5549      </p>
5550
5551
5552
5553 
5554     
5555     
5556     
5557      <p>By deafult, if cut-off of overshoots is switched
5558on for the
5559upstream-spline scheme (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>),
5560no overshoots are permitted at all. If <b>overshoot_limit_e</b>
5561is given a non-zero value, overshoots with the respective
5562amplitude (both upward and downward) are allowed.&nbsp; </p>
5563
5564
5565
5566
5567     
5568     
5569     
5570      <p>Only positive values are allowed for <b>overshoot_limit_e</b>.</p>
5571
5572
5573
5574
5575      </td>
5576
5577
5578
5579 </tr>
5580
5581
5582
5583 <tr>
5584
5585
5586
5587 <td style="vertical-align: top;"> 
5588     
5589     
5590     
5591      <p><a name="overshoot_limit_pt"></a><b>overshoot_limit_pt</b></p>
5592
5593
5594
5595
5596      </td>
5597
5598
5599
5600 <td style="vertical-align: top;">R</td>
5601
5602
5603
5604
5605      <td style="vertical-align: top;"><i>0.0</i></td>
5606
5607
5608
5609
5610      <td style="vertical-align: top;"> 
5611     
5612     
5613     
5614      <p>Allowed limit
5615for the overshooting of potential temperature in
5616case that the upstream-spline scheme is switched on (in K).&nbsp; </p>
5617
5618
5619
5620
5621     
5622     
5623     
5624      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
5625      </p>
5626
5627
5628
5629 
5630     
5631     
5632     
5633      <p>Only positive values are allowed for <b>overshoot_limit_pt</b>.</p>
5634
5635
5636
5637
5638      </td>
5639
5640
5641
5642 </tr>
5643
5644
5645
5646 <tr>
5647
5648
5649
5650 <td style="vertical-align: top;"> 
5651     
5652     
5653     
5654      <p><a name="overshoot_limit_u"></a><b>overshoot_limit_u</b></p>
5655
5656
5657
5658
5659      </td>
5660
5661
5662
5663 <td style="vertical-align: top;">R</td>
5664
5665
5666
5667
5668      <td style="vertical-align: top;"><i>0.0</i></td>
5669
5670
5671
5672
5673      <td style="vertical-align: top;">Allowed limit for the
5674overshooting of
5675the u-component of velocity in case that the upstream-spline scheme is
5676switched on (in m/s).
5677     
5678     
5679     
5680      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
5681      </p>
5682
5683
5684
5685 
5686     
5687     
5688     
5689      <p>Only positive values are allowed for <b>overshoot_limit_u</b>.</p>
5690
5691
5692
5693
5694      </td>
5695
5696
5697
5698 </tr>
5699
5700
5701
5702 <tr>
5703
5704
5705
5706 <td style="vertical-align: top;"> 
5707     
5708     
5709     
5710      <p><a name="overshoot_limit_v"></a><b>overshoot_limit_v</b></p>
5711
5712
5713
5714
5715      </td>
5716
5717
5718
5719 <td style="vertical-align: top;">R</td>
5720
5721
5722
5723
5724      <td style="vertical-align: top;"><i>0.0</i></td>
5725
5726
5727
5728
5729      <td style="vertical-align: top;"> 
5730     
5731     
5732     
5733      <p>Allowed limit
5734for the overshooting of the v-component of
5735velocity in case that the upstream-spline scheme is switched on
5736(in m/s).&nbsp; </p>
5737
5738
5739
5740 
5741     
5742     
5743     
5744      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
5745      </p>
5746
5747
5748
5749 
5750     
5751     
5752     
5753      <p>Only positive values are allowed for <b>overshoot_limit_v</b>.</p>
5754
5755
5756
5757
5758      </td>
5759
5760
5761
5762 </tr>
5763
5764
5765
5766 <tr>
5767
5768
5769
5770 <td style="vertical-align: top;"> 
5771     
5772     
5773     
5774      <p><a name="overshoot_limit_w"></a><b>overshoot_limit_w</b></p>
5775
5776
5777
5778
5779      </td>
5780
5781
5782
5783 <td style="vertical-align: top;">R</td>
5784
5785
5786
5787
5788      <td style="vertical-align: top;"><i>0.0</i></td>
5789
5790
5791
5792
5793      <td style="vertical-align: top;"> 
5794     
5795     
5796     
5797      <p>Allowed limit
5798for the overshooting of the w-component of
5799velocity in case that the upstream-spline scheme is switched on
5800(in m/s).&nbsp; </p>
5801
5802
5803
5804 
5805     
5806     
5807     
5808      <p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.&nbsp;
5809      </p>
5810
5811
5812
5813 
5814     
5815     
5816     
5817      <p>Only positive values are permitted for <b>overshoot_limit_w</b>.</p>
5818
5819
5820
5821
5822      </td>
5823
5824
5825
5826 </tr>
5827
5828
5829
5830 <tr>
5831
5832
5833
5834 <td style="vertical-align: top;"> 
5835     
5836     
5837     
5838      <p><a name="passive_scalar"></a><b>passive_scalar</b></p>
5839
5840
5841
5842
5843      </td>
5844
5845
5846
5847 <td style="vertical-align: top;">L</td>
5848
5849
5850
5851
5852      <td style="vertical-align: top;"><i>.F.</i></td>
5853
5854
5855
5856
5857      <td style="vertical-align: top;"> 
5858     
5859     
5860     
5861      <p>Parameter to
5862switch on the prognostic equation for a passive
5863scalar. <br>
5864
5865
5866
5867 </p>
5868
5869
5870
5871 
5872     
5873     
5874     
5875      <p>The initial vertical profile
5876of s can be set via parameters <a href="#s_surface">s_surface</a>,
5877      <a href="#s_vertical_gradient">s_vertical_gradient</a>
5878and&nbsp; <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
5879Boundary conditions can be set via <a href="#s_surface_initial_change">s_surface_initial_change</a>
5880and <a href="#surface_scalarflux">surface_scalarflux</a>.&nbsp;
5881      </p>
5882
5883
5884
5885 
5886     
5887     
5888     
5889      <p><b>Note:</b> <br>
5890
5891
5892
5893
5894With <span style="font-weight: bold;">passive_scalar</span>
5895switched
5896on, the simultaneous use of humidity (see&nbsp;<a href="#humidity">humidity</a>)
5897is impossible.</p>
5898
5899
5900
5901 </td>
5902
5903
5904
5905 </tr>
5906
5907
5908
5909 <tr>
5910
5911
5912
5913 <td style="vertical-align: top;"> 
5914     
5915     
5916     
5917      <p><a name="phi"></a><b>phi</b></p>
5918
5919
5920
5921
5922      </td>
5923
5924
5925
5926 <td style="vertical-align: top;">R</td>
5927
5928
5929
5930
5931      <td style="vertical-align: top;"><i>55.0</i></td>
5932
5933
5934
5935
5936      <td style="vertical-align: top;"> 
5937     
5938     
5939     
5940      <p>Geographical
5941latitude (in degrees).&nbsp; </p>
5942
5943
5944
5945 
5946     
5947     
5948     
5949      <p>The value of
5950this parameter determines the value of the
5951Coriolis parameters f and f*, provided that the angular velocity (see <a href="#omega">omega</a>)
5952is non-zero.</p>
5953
5954
5955
5956 </td>
5957
5958
5959
5960 </tr>
5961
5962
5963
5964 <tr>
5965
5966
5967
5968 <td style="vertical-align: top;"> 
5969     
5970     
5971     
5972      <p><a name="prandtl_layer"></a><b>prandtl_layer</b></p>
5973
5974
5975
5976
5977      </td>
5978
5979
5980
5981 <td style="vertical-align: top;">L</td>
5982
5983
5984
5985
5986      <td style="vertical-align: top;"><i>.T.</i></td>
5987
5988
5989
5990
5991      <td style="vertical-align: top;"> 
5992     
5993     
5994     
5995      <p>Parameter to
5996switch on a Prandtl layer.&nbsp; </p>
5997
5998
5999
6000 
6001     
6002     
6003     
6004      <p>By default,
6005a Prandtl layer is switched on at the bottom
6006boundary between z = 0 and z = 0.5 * <a href="#dz">dz</a>
6007(the first computational grid point above ground for u, v and the
6008scalar quantities).
6009In this case, at the bottom boundary, free-slip conditions for u and v
6010(see <a href="#bc_uv_b">bc_uv_b</a>)
6011are not allowed. Likewise, laminar
6012simulations with constant eddy diffusivities (<a href="#km_constant">km_constant</a>)
6013are forbidden.&nbsp; </p>
6014
6015
6016
6017 
6018     
6019     
6020     
6021      <p>With Prandtl-layer
6022switched off, the TKE boundary condition <a href="#bc_e_b">bc_e_b</a>
6023= '<i>(u*)**2+neumann'</i> must not be used and is
6024automatically
6025changed to <i>'neumann'</i> if necessary.&nbsp; Also,
6026the pressure
6027boundary condition <a href="#bc_p_b">bc_p_b</a>
6028= <i>'neumann+inhomo'</i>&nbsp; is not allowed. </p>
6029
6030
6031
6032
6033     
6034     
6035     
6036      <p>The roughness length is declared via the parameter <a href="#roughness_length">roughness_length</a>.</p>
6037
6038
6039
6040
6041      </td>
6042
6043
6044
6045 </tr>
6046
6047
6048
6049 <tr>
6050
6051
6052
6053 <td style="vertical-align: top;"> 
6054     
6055     
6056     
6057      <p><a name="precipitation"></a><b>precipitation</b></p>
6058
6059
6060
6061
6062      </td>
6063
6064
6065
6066 <td style="vertical-align: top;">L</td>
6067
6068
6069
6070
6071      <td style="vertical-align: top;"><span style="font-style: italic;">.F.</span></td>
6072
6073
6074
6075 <td style="vertical-align: top;"> 
6076     
6077     
6078     
6079      <p>Parameter to switch
6080on the precipitation scheme.<br>
6081
6082
6083
6084 </p>
6085
6086
6087
6088 
6089     
6090     
6091     
6092      <p>For
6093precipitation processes PALM uses a simplified Kessler
6094scheme. This scheme only considers the
6095so-called autoconversion, that means the generation of rain water by
6096coagulation of cloud drops among themselves. Precipitation begins and
6097is immediately removed from the flow as soon as the liquid water
6098content exceeds the critical value of 0.5 g/kg.</p>
6099
6100
6101
6102     
6103     
6104     
6105      <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>
6106
6107
6108
6109 </td>
6110
6111
6112
6113 </tr>
6114
6115
6116
6117
6118    <tr>
6119
6120
6121
6122      <td style="vertical-align: top;"><a name="pt_reference"></a><span style="font-weight: bold;">pt_reference</span></td>
6123
6124
6125
6126      <td style="vertical-align: top;">R</td>
6127
6128
6129
6130      <td style="vertical-align: top;"><span style="font-style: italic;">use horizontal average as
6131refrence</span></td>
6132
6133
6134
6135      <td style="vertical-align: top;">Reference
6136temperature to be used in all buoyancy terms (in K).<br>
6137
6138
6139
6140      <br>
6141
6142
6143
6144By
6145default, the instantaneous horizontal average over the total model
6146domain is used.<br>
6147
6148
6149
6150      <br>
6151
6152
6153
6154      <span style="font-weight: bold;">Attention:</span><br>
6155
6156
6157
6158In 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>
6159
6160
6161
6162    </tr>
6163
6164
6165
6166    <tr>
6167
6168
6169
6170 <td style="vertical-align: top;"> 
6171     
6172     
6173     
6174      <p><a name="pt_surface"></a><b>pt_surface</b></p>
6175
6176
6177
6178
6179      </td>
6180
6181
6182
6183 <td style="vertical-align: top;">R</td>
6184
6185
6186
6187
6188      <td style="vertical-align: top;"><i>300.0</i></td>
6189
6190
6191
6192
6193      <td style="vertical-align: top;"> 
6194     
6195     
6196     
6197      <p>Surface
6198potential temperature (in K).&nbsp; </p>
6199
6200
6201
6202 
6203     
6204     
6205     
6206      <p>This
6207parameter assigns the value of the potential temperature
6208      <span style="font-weight: bold;">pt</span> at the surface (k=0)<b>.</b> Starting from this value,
6209the
6210initial vertical temperature profile is constructed with <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
6211and <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level
6212      </a>.
6213This profile is also used for the 1d-model as a stationary profile.</p>
6214
6215
6216
6217     
6218     
6219     
6220      <p><span style="font-weight: bold;">Attention:</span><br>
6221
6222
6223
6224In case of ocean runs (see <a href="#ocean">ocean</a>),
6225this parameter gives the temperature value at the sea surface, which is
6226at k=nzt. The profile is then constructed from the surface down to the
6227bottom of the model.</p>
6228
6229
6230
6231
6232      </td>
6233
6234
6235
6236 </tr>
6237
6238
6239
6240 <tr>
6241
6242
6243
6244 <td style="vertical-align: top;"> 
6245     
6246     
6247     
6248      <p><a name="pt_surface_initial_change"></a><b>pt_surface_initial</b>
6249      <br>
6250
6251
6252
6253 <b>_change</b></p>
6254
6255
6256
6257 </td>
6258
6259
6260
6261 <td style="vertical-align: top;">R</td>
6262
6263
6264
6265 <td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
6266
6267
6268
6269 </td>
6270
6271
6272
6273
6274      <td style="vertical-align: top;"> 
6275     
6276     
6277     
6278      <p>Change in
6279surface temperature to be made at the beginning of
6280the 3d run
6281(in K).&nbsp; </p>
6282
6283
6284
6285 
6286     
6287     
6288     
6289      <p>If <b>pt_surface_initial_change</b>
6290is set to a non-zero
6291value, the near surface sensible heat flux is not allowed to be given
6292simultaneously (see <a href="#surface_heatflux">surface_heatflux</a>).</p>
6293
6294
6295
6296
6297      </td>
6298
6299
6300
6301 </tr>
6302
6303
6304
6305 <tr>
6306
6307
6308
6309 <td style="vertical-align: top;"> 
6310     
6311     
6312     
6313      <p><a name="pt_vertical_gradient"></a><b>pt_vertical_gradient</b></p>
6314
6315
6316
6317
6318      </td>
6319
6320
6321
6322 <td style="vertical-align: top;">R (10)</td>
6323
6324
6325
6326
6327      <td style="vertical-align: top;"><i>10 * 0.0</i></td>
6328
6329
6330
6331
6332      <td style="vertical-align: top;"> 
6333     
6334     
6335     
6336      <p>Temperature
6337gradient(s) of the initial temperature profile (in
6338K
6339/ 100 m).&nbsp; </p>
6340
6341
6342
6343 
6344     
6345     
6346     
6347      <p>This temperature gradient
6348holds starting from the height&nbsp;
6349level defined by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>
6350(precisely: for all uv levels k where zu(k) &gt;
6351pt_vertical_gradient_level,
6352pt_init(k) is set: pt_init(k) = pt_init(k-1) + dzu(k) * <b>pt_vertical_gradient</b>)
6353up to the top boundary or up to the next height level defined
6354by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>.
6355A total of 10 different gradients for 11 height intervals (10 intervals
6356if <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>(1)
6357= <i>0.0</i>) can be assigned. The surface temperature is
6358assigned via <a href="#pt_surface">pt_surface</a>.&nbsp;
6359      </p>
6360
6361
6362
6363 
6364     
6365     
6366     
6367      <p>Example:&nbsp; </p>
6368
6369
6370
6371 
6372     
6373     
6374     
6375      <ul>
6376
6377
6378
6379 
6380       
6381       
6382       
6383        <p><b>pt_vertical_gradient</b>
6384= <i>1.0</i>, <i>0.5</i>,&nbsp; <br>
6385
6386
6387
6388
6389        <b>pt_vertical_gradient_level</b> = <i>500.0</i>,
6390        <i>1000.0</i>,</p>
6391
6392
6393
6394 
6395     
6396     
6397     
6398      </ul>
6399
6400
6401
6402 
6403     
6404     
6405     
6406      <p>That
6407defines the temperature profile to be neutrally
6408stratified
6409up to z = 500.0 m with a temperature given by <a href="#pt_surface">pt_surface</a>.
6410For 500.0 m &lt; z &lt;= 1000.0 m the temperature gradient is
64111.0 K /
6412100 m and for z &gt; 1000.0 m up to the top boundary it is
64130.5 K / 100 m (it is assumed that the assigned height levels correspond
6414with uv levels).</p>
6415
6416
6417
6418     
6419     
6420     
6421      <p><span style="font-weight: bold;">Attention:</span><br>
6422
6423
6424
6425In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>),
6426the profile is constructed like described above, but starting from the
6427sea surface (k=nzt) down to the bottom boundary of the model. Height
6428levels 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>
6429
6430
6431
6432 </td>
6433
6434
6435
6436 </tr>
6437
6438
6439
6440 <tr>
6441
6442
6443
6444 <td style="vertical-align: top;"> 
6445     
6446     
6447     
6448      <p><a name="pt_vertical_gradient_level"></a><b>pt_vertical_gradient</b>
6449      <br>
6450
6451
6452
6453 <b>_level</b></p>
6454
6455
6456
6457 </td>
6458
6459
6460
6461 <td style="vertical-align: top;">R (10)</td>
6462
6463
6464
6465 <td style="vertical-align: top;"> 
6466     
6467     
6468     
6469      <p><i>10 *</i>&nbsp;
6470      <span style="font-style: italic;">0.0</span><br>
6471
6472
6473
6474
6475      </p>
6476
6477
6478
6479 </td>
6480
6481
6482
6483 <td style="vertical-align: top;">
6484     
6485     
6486     
6487      <p>Height level from which on the temperature gradient defined by
6488      <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
6489is effective (in m).&nbsp; </p>
6490
6491
6492
6493 
6494     
6495     
6496     
6497      <p>The height levels have to be assigned in ascending order. The
6498default values result in a neutral stratification regardless of the
6499values of <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
6500(unless the top boundary of the model is higher than 100000.0 m).
6501For the piecewise construction of temperature profiles see <a href="#pt_vertical_gradient">pt_vertical_gradient</a>.</p>
6502
6503
6504
6505      <span style="font-weight: bold;">Attention:</span><br>
6506
6507
6508
6509In 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.
6510      </td>
6511
6512
6513
6514 </tr>
6515
6516
6517
6518 <tr>
6519
6520
6521
6522 <td style="vertical-align: top;"> 
6523     
6524     
6525     
6526      <p><a name="q_surface"></a><b>q_surface</b></p>
6527
6528
6529
6530
6531      </td>
6532
6533
6534
6535 <td style="vertical-align: top;">R</td>
6536
6537
6538
6539
6540      <td style="vertical-align: top;"><i>0.0</i></td>
6541
6542
6543
6544
6545      <td style="vertical-align: top;"> 
6546     
6547     
6548     
6549      <p>Surface
6550specific humidity / total water content (kg/kg).&nbsp; </p>
6551
6552
6553
6554 
6555     
6556     
6557     
6558      <p>This
6559parameter assigns the value of the specific humidity q at
6560the surface (k=0).&nbsp; Starting from this value, the initial
6561humidity
6562profile is constructed with&nbsp; <a href="#q_vertical_gradient">q_vertical_gradient</a>
6563and <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
6564This profile is also used for the 1d-model as a stationary profile.</p>
6565
6566
6567
6568
6569      </td>
6570
6571
6572
6573 </tr>
6574
6575
6576
6577 <tr>
6578
6579
6580
6581 <td style="vertical-align: top;"> 
6582     
6583     
6584     
6585      <p><a name="q_surface_initial_change"></a><b>q_surface_initial</b>
6586      <br>
6587
6588
6589
6590 <b>_change</b></p>
6591
6592
6593
6594 </td>
6595
6596
6597
6598 <td style="vertical-align: top;">R<br>
6599
6600
6601
6602 </td>
6603
6604
6605
6606 <td style="vertical-align: top;"><i>0.0</i></td>
6607
6608
6609
6610
6611      <td style="vertical-align: top;"> 
6612     
6613     
6614     
6615      <p>Change in
6616surface specific humidity / total water content to
6617be made at the beginning
6618of the 3d run (kg/kg).&nbsp; </p>
6619
6620
6621
6622 
6623     
6624     
6625     
6626      <p>If <b>q_surface_initial_change</b><i>
6627      </i>is set to a
6628non-zero value the
6629near surface latent heat flux (water flux) is not allowed to be given
6630simultaneously (see <a href="#surface_waterflux">surface_waterflux</a>).</p>
6631
6632
6633
6634
6635      </td>
6636
6637
6638
6639 </tr>
6640
6641
6642
6643 <tr>
6644
6645
6646
6647 <td style="vertical-align: top;"> 
6648     
6649     
6650     
6651      <p><a name="q_vertical_gradient"></a><b>q_vertical_gradient</b></p>
6652
6653
6654
6655
6656      </td>
6657
6658
6659
6660 <td style="vertical-align: top;">R (10)</td>
6661
6662
6663
6664
6665      <td style="vertical-align: top;"><i>10 * 0.0</i></td>
6666
6667
6668
6669
6670      <td style="vertical-align: top;"> 
6671     
6672     
6673     
6674      <p>Humidity
6675gradient(s) of the initial humidity profile
6676(in 1/100 m).&nbsp; </p>
6677
6678
6679
6680 
6681     
6682     
6683     
6684      <p>This humidity gradient
6685holds starting from the height
6686level&nbsp; defined by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>
6687(precisely: for all uv levels k, where zu(k) &gt;
6688q_vertical_gradient_level,
6689q_init(k) is set: q_init(k) = q_init(k-1) + dzu(k) * <b>q_vertical_gradient</b>)
6690up to the top boundary or up to the next height level defined
6691by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
6692A total of 10 different gradients for 11 height intervals (10 intervals
6693if <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>(1)
6694= <i>0.0</i>) can be asigned. The surface humidity is
6695assigned
6696via <a href="#q_surface">q_surface</a>. </p>
6697
6698
6699
6700
6701     
6702     
6703     
6704      <p>Example:&nbsp; </p>
6705
6706
6707
6708 
6709     
6710     
6711     
6712      <ul>
6713
6714
6715
6716 
6717       
6718       
6719       
6720        <p><b>q_vertical_gradient</b>
6721= <i>0.001</i>, <i>0.0005</i>,&nbsp; <br>
6722
6723
6724
6725
6726        <b>q_vertical_gradient_level</b> = <i>500.0</i>,
6727        <i>1000.0</i>,</p>
6728
6729
6730
6731 
6732     
6733     
6734     
6735      </ul>
6736
6737
6738
6739
6740That defines the humidity to be constant with height up to z =
6741500.0
6742m with a
6743value given by <a href="#q_surface">q_surface</a>.
6744For 500.0 m &lt; z &lt;= 1000.0 m the humidity gradient is
67450.001 / 100
6746m and for z &gt; 1000.0 m up to the top boundary it is
67470.0005 / 100 m (it is assumed that the assigned height levels
6748correspond with uv
6749levels). </td>
6750
6751
6752
6753 </tr>
6754
6755
6756
6757 <tr>
6758
6759
6760
6761 <td style="vertical-align: top;"> 
6762     
6763     
6764     
6765      <p><a name="q_vertical_gradient_level"></a><b>q_vertical_gradient</b>
6766      <br>
6767
6768
6769
6770 <b>_level</b></p>
6771
6772
6773
6774 </td>
6775
6776
6777
6778 <td style="vertical-align: top;">R (10)</td>
6779
6780
6781
6782 <td style="vertical-align: top;"> 
6783     
6784     
6785     
6786      <p><i>10 *</i>&nbsp;
6787      <i>0.0</i></p>
6788
6789
6790
6791 </td>
6792
6793
6794
6795 <td style="vertical-align: top;"> 
6796     
6797     
6798     
6799      <p>Height level from
6800which on the humidity gradient defined by <a href="#q_vertical_gradient">q_vertical_gradient</a>
6801is effective (in m).&nbsp; </p>
6802
6803
6804
6805 
6806     
6807     
6808     
6809      <p>The height levels
6810are to be assigned in ascending order. The
6811default values result in a humidity constant with height regardless of
6812the values of <a href="#q_vertical_gradient">q_vertical_gradient</a>
6813(unless the top boundary of the model is higher than 100000.0 m). For
6814the piecewise construction of humidity profiles see <a href="#q_vertical_gradient">q_vertical_gradient</a>.</p>
6815
6816
6817
6818
6819      </td>
6820
6821
6822
6823 </tr>
6824
6825
6826
6827 <tr>
6828
6829
6830
6831 <td style="vertical-align: top;"> 
6832     
6833     
6834     
6835      <p><a name="radiation"></a><b>radiation</b></p>
6836
6837
6838
6839
6840      </td>
6841
6842
6843
6844 <td style="vertical-align: top;">L</td>
6845
6846
6847
6848
6849      <td style="vertical-align: top;"><i>.F.</i></td>
6850
6851
6852
6853
6854      <td style="vertical-align: top;"> 
6855     
6856     
6857     
6858      <p>Parameter to
6859switch on longwave radiation cooling at
6860cloud-tops.&nbsp; </p>
6861
6862
6863
6864 
6865     
6866     
6867     
6868      <p>Long-wave radiation
6869processes are parameterized by the
6870effective emissivity, which considers only the absorption and emission
6871of long-wave radiation at cloud droplets. The radiation scheme can be
6872used only with <a href="#cloud_physics">cloud_physics</a>
6873= .TRUE. .</p>
6874
6875
6876
6877 </td>
6878
6879
6880
6881 </tr>
6882
6883
6884
6885 <tr>
6886
6887
6888
6889 <td style="vertical-align: top;"> 
6890     
6891     
6892     
6893      <p><a name="random_generator"></a><b>random_generator</b></p>
6894
6895
6896
6897
6898      </td>
6899
6900
6901
6902 <td style="vertical-align: top;">C * 20</td>
6903
6904
6905
6906
6907      <td style="vertical-align: top;"> 
6908     
6909     
6910     
6911      <p><i>'numerical</i><br>
6912
6913
6914
6915
6916      <i>recipes'</i></p>
6917
6918
6919
6920 </td>
6921
6922
6923
6924 <td style="vertical-align: top;"> 
6925     
6926     
6927     
6928      <p>Random number
6929generator to be used for creating uniformly
6930distributed random numbers. <br>
6931
6932
6933
6934 </p>
6935
6936
6937
6938 
6939     
6940     
6941     
6942      <p>It is
6943used if random perturbations are to be imposed on the
6944velocity field or on the surface heat flux field (see <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>
6945and <a href="chapter_4.2.html#random_heatflux">random_heatflux</a>).
6946By default, the "Numerical Recipes" random number generator is used.
6947This one provides exactly the same order of random numbers on all
6948different machines and should be used in particular for comparison runs.<br>
6949
6950
6951
6952
6953      <br>
6954
6955
6956
6957
6958Besides, a system-specific generator is available ( <b>random_generator</b>
6959= <i>'system-specific')</i> which should particularly be
6960used for runs
6961on vector parallel computers (NEC), because the default generator
6962cannot be vectorized and therefore significantly drops down the code
6963performance on these machines.<br>
6964
6965
6966
6967 </p>
6968
6969
6970
6971 <span style="font-weight: bold;">Note:</span><br>
6972
6973
6974
6975
6976Results from two otherwise identical model runs will not be comparable
6977one-to-one if they used different random number generators.</td>
6978
6979
6980
6981 </tr>
6982
6983
6984
6985
6986    <tr>
6987
6988
6989
6990 <td style="vertical-align: top;"> 
6991     
6992     
6993     
6994      <p><a name="random_heatflux"></a><b>random_heatflux</b></p>
6995
6996
6997
6998
6999      </td>
7000
7001
7002
7003 <td style="vertical-align: top;">L</td>
7004
7005
7006
7007
7008      <td style="vertical-align: top;"><i>.F.</i></td>
7009
7010
7011
7012
7013      <td style="vertical-align: top;"> 
7014     
7015     
7016     
7017      <p>Parameter to
7018impose random perturbations on the internal two-dimensional near
7019surface heat flux field <span style="font-style: italic;">shf</span>.
7020      <br>
7021
7022
7023
7024 </p>
7025
7026
7027
7028If a near surface heat flux is used as bottom
7029boundary
7030condition (see <a href="#surface_heatflux">surface_heatflux</a>),
7031it is by default assumed to be horizontally homogeneous. Random
7032perturbations can be imposed on the internal
7033two-dimensional&nbsp;heat flux field <span style="font-style: italic;">shf</span> by assigning <b>random_heatflux</b>
7034= <i>.T.</i>. The disturbed heat flux field is calculated
7035by
7036multiplying the
7037values at each mesh point with a normally distributed random number
7038with a mean value and standard deviation of 1. This is repeated after
7039every timestep.<br>
7040
7041
7042
7043 <br>
7044
7045
7046
7047
7048In case of a non-flat <a href="#topography">topography</a>,&nbsp;assigning
7049      <b>random_heatflux</b>
7050= <i>.T.</i> imposes random perturbations on the
7051combined&nbsp;heat
7052flux field <span style="font-style: italic;">shf</span>
7053composed of <a href="#surface_heatflux">surface_heatflux</a>
7054at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
7055at the topography top face.</td>
7056
7057
7058
7059 </tr>
7060
7061
7062
7063 <tr>
7064
7065
7066
7067 <td style="vertical-align: top;"> 
7068     
7069     
7070     
7071      <p><a name="rif_max"></a><b>rif_max</b></p>
7072
7073
7074
7075
7076      </td>
7077
7078
7079
7080 <td style="vertical-align: top;">R</td>
7081
7082
7083
7084
7085      <td style="vertical-align: top;"><i>1.0</i></td>
7086
7087
7088
7089
7090      <td style="vertical-align: top;"> 
7091     
7092     
7093     
7094      <p>Upper limit of
7095the flux-Richardson number.&nbsp; </p>
7096
7097
7098
7099 
7100     
7101     
7102     
7103      <p>With the
7104Prandtl layer switched on (see <a href="#prandtl_layer">prandtl_layer</a>),
7105flux-Richardson numbers (rif) are calculated for z=z<sub>p</sub>
7106(k=1)
7107in the 3d-model (in the 1d model for all heights). Their values in
7108particular determine the
7109values of the friction velocity (1d- and 3d-model) and the values of
7110the eddy diffusivity (1d-model). With small wind velocities at the
7111Prandtl layer top or small vertical wind shears in the 1d-model, rif
7112can take up unrealistic large values. They are limited by an upper (<span style="font-weight: bold;">rif_max</span>) and lower
7113limit (see <a href="#rif_min">rif_min</a>)
7114for the flux-Richardson number. The condition <b>rif_max</b>
7115&gt; <b>rif_min</b>
7116must be met.</p>
7117
7118
7119
7120 </td>
7121
7122
7123
7124 </tr>
7125
7126
7127
7128 <tr>
7129
7130
7131
7132 <td style="vertical-align: top;"> 
7133     
7134     
7135     
7136      <p><a name="rif_min"></a><b>rif_min</b></p>
7137
7138
7139
7140
7141      </td>
7142
7143
7144
7145 <td style="vertical-align: top;">R</td>
7146
7147
7148
7149
7150      <td style="vertical-align: top;"><i>- 5.0</i></td>
7151
7152
7153
7154
7155      <td style="vertical-align: top;"> 
7156     
7157     
7158     
7159      <p>Lower limit of
7160the flux-Richardson number.&nbsp; </p>
7161
7162
7163
7164 
7165     
7166     
7167     
7168      <p>For further
7169explanations see <a href="#rif_max">rif_max</a>.
7170The condition <b>rif_max</b> &gt; <b>rif_min </b>must
7171be met.</p>
7172
7173
7174
7175 </td>
7176
7177
7178
7179 </tr>
7180
7181
7182
7183 <tr>
7184
7185
7186
7187 <td style="vertical-align: top;"> 
7188     
7189     
7190     
7191      <p><a name="roughness_length"></a><b>roughness_length</b></p>
7192
7193
7194
7195
7196      </td>
7197
7198
7199
7200 <td style="vertical-align: top;">R</td>
7201
7202
7203
7204
7205      <td style="vertical-align: top;"><i>0.1</i></td>
7206
7207
7208
7209
7210      <td style="vertical-align: top;"> 
7211     
7212     
7213     
7214      <p>Roughness
7215length (in m).&nbsp; </p>
7216
7217
7218
7219 
7220     
7221     
7222     
7223      <p>This parameter is
7224effective only in case that a Prandtl layer
7225is switched
7226on (see <a href="#prandtl_layer">prandtl_layer</a>).</p>
7227
7228
7229
7230
7231      </td>
7232
7233
7234
7235 </tr>
7236
7237
7238
7239 <tr>
7240
7241
7242
7243      <td style="vertical-align: top;"><a name="sa_surface"></a><span style="font-weight: bold;">sa_surface</span></td>
7244
7245
7246
7247      <td style="vertical-align: top;">R</td>
7248
7249
7250
7251      <td style="vertical-align: top;"><span style="font-style: italic;">35.0</span></td>
7252
7253
7254
7255      <td style="vertical-align: top;"> 
7256     
7257     
7258     
7259      <p>Surface salinity (in psu).&nbsp;</p>
7260
7261
7262
7263This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).
7264     
7265     
7266     
7267      <p>This
7268parameter 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,
7269the
7270initial 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>
7271and&nbsp;<a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level
7272      </a>.</p>
7273
7274
7275
7276      </td>
7277
7278
7279
7280    </tr>
7281
7282
7283
7284    <tr>
7285
7286
7287
7288      <td style="vertical-align: top;"><a name="sa_vertical_gradient"></a><span style="font-weight: bold;">sa_vertical_gradient</span></td>
7289
7290
7291
7292      <td style="vertical-align: top;">R(10)</td>
7293
7294
7295
7296      <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
7297
7298
7299
7300      <td style="vertical-align: top;">
7301     
7302     
7303     
7304      <p>Salinity gradient(s) of the initial salinity profile (in psu
7305/ 100 m).&nbsp; </p>
7306
7307
7308
7309 
7310     
7311     
7312     
7313      <p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
7314
7315
7316
7317     
7318     
7319     
7320      <p>This salinity gradient
7321holds starting from the height&nbsp;
7322level defined by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>
7323(precisely: for all uv levels k where zu(k) &lt;
7324sa_vertical_gradient_level, sa_init(k) is set: sa_init(k) =
7325sa_init(k+1) - dzu(k+1) * <b>sa_vertical_gradient</b>) down to the bottom boundary or down to the next height level defined
7326by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>.
7327A total of 10 different gradients for 11 height intervals (10 intervals
7328if <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>(1)
7329= <i>0.0</i>) can be assigned. The surface salinity at k=nzt is
7330assigned via <a href="chapter_4.1.html#sa_surface">sa_surface</a>.&nbsp;
7331      </p>
7332
7333
7334
7335 
7336     
7337     
7338     
7339      <p>Example:&nbsp; </p>
7340
7341
7342
7343 
7344     
7345     
7346     
7347      <ul>
7348
7349
7350
7351       
7352       
7353       
7354        <p><b>sa_vertical_gradient</b>
7355= <i>1.0</i>, <i>0.5</i>,&nbsp; <br>
7356
7357
7358
7359
7360        <b>sa_vertical_gradient_level</b> = <i>-500.0</i>,
7361-<i>1000.0</i>,</p>
7362
7363
7364
7365     
7366     
7367     
7368      </ul>
7369
7370
7371
7372 
7373     
7374     
7375     
7376      <p>That
7377defines 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>.
7378For -500.0 m &lt; z &lt;= -1000.0 m the salinity gradient is
73791.0 psu /
7380100 m and for z &lt; -1000.0 m down to the bottom boundary it is
73810.5 psu / 100 m (it is assumed that the assigned height levels correspond
7382with uv levels).</p>
7383
7384
7385
7386      </td>
7387
7388
7389
7390    </tr>
7391
7392
7393
7394    <tr>
7395
7396
7397
7398      <td style="vertical-align: top;"><a name="sa_vertical_gradient_level"></a><span style="font-weight: bold;">sa_vertical_gradient_level</span></td>
7399
7400
7401
7402      <td style="vertical-align: top;">R(10)</td>
7403
7404
7405
7406      <td style="vertical-align: top;"><span style="font-style: italic;">10 * 0.0</span></td>
7407
7408
7409
7410      <td style="vertical-align: top;">
7411     
7412     
7413     
7414      <p>Height level from which on the salinity gradient defined by <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
7415is effective (in m).&nbsp; </p>
7416
7417
7418
7419 
7420     
7421     
7422     
7423      <p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
7424
7425
7426
7427     
7428     
7429     
7430      <p>The height levels have to be assigned in descending order. The
7431default values result in a constant salinity profile regardless of the
7432values of <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
7433(unless the bottom boundary of the model is lower than -100000.0 m).
7434For the piecewise construction of salinity profiles see <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>.</p>
7435
7436
7437
7438      </td>
7439
7440
7441
7442    </tr>
7443
7444
7445
7446    <tr>
7447
7448
7449
7450 <td style="vertical-align: top;"> 
7451     
7452     
7453     
7454      <p><a name="scalar_advec"></a><b>scalar_advec</b></p>
7455
7456
7457
7458
7459      </td>
7460
7461
7462
7463 <td style="vertical-align: top;">C * 10</td>
7464
7465
7466
7467
7468      <td style="vertical-align: top;"><i>'pw-scheme'</i></td>
7469
7470
7471
7472
7473      <td style="vertical-align: top;"> 
7474     
7475     
7476     
7477      <p>Advection
7478scheme to be used for the scalar quantities.&nbsp; </p>
7479
7480
7481
7482 
7483     
7484     
7485     
7486      <p>The
7487user can choose between the following schemes:<br>
7488
7489
7490
7491 </p>
7492
7493
7494
7495 
7496     
7497     
7498     
7499      <p><span style="font-style: italic;">'pw-scheme'</span><br>
7500
7501
7502
7503
7504      </p>
7505
7506
7507
7508 
7509     
7510     
7511     
7512      <div style="margin-left: 40px;">The scheme of
7513Piascek and
7514Williams (1970, J. Comp. Phys., 6,
7515392-405) with central differences in the form C3 is used.<br>
7516
7517
7518
7519
7520If intermediate Euler-timesteps are carried out in case of <a href="#timestep_scheme">timestep_scheme</a>
7521= <span style="font-style: italic;">'leapfrog+euler'</span>
7522the
7523advection scheme is - for the Euler-timestep - automatically switched
7524to an upstream-scheme. <br>
7525
7526
7527
7528 </div>
7529
7530
7531
7532 <br>
7533
7534
7535
7536 
7537     
7538     
7539     
7540      <p><span style="font-style: italic;">'bc-scheme'</span><br>
7541
7542
7543
7544
7545      </p>
7546
7547
7548
7549 
7550     
7551     
7552     
7553      <div style="margin-left: 40px;">The Bott
7554scheme modified by
7555Chlond (1994, Mon.
7556Wea. Rev., 122, 111-125). This is a conservative monotonous scheme with
7557very small numerical diffusion and therefore very good conservation of
7558scalar flow features. The scheme however, is computationally very
7559expensive both because it is expensive itself and because it does (so
7560far) not allow specific code optimizations (e.g. cache optimization).
7561Choice of this
7562scheme forces the Euler timestep scheme to be used for the scalar
7563quantities. For output of horizontally averaged
7564profiles of the resolved / total heat flux, <a href="chapter_4.2.html#data_output_pr">data_output_pr</a>
7565= <i>'w*pt*BC'</i> / <i>'wptBC' </i>should
7566be used, instead of the
7567standard profiles (<span style="font-style: italic;">'w*pt*'</span>
7568and <span style="font-style: italic;">'wpt'</span>)
7569because these are
7570too inaccurate with this scheme. However, for subdomain analysis (see <a href="#statistic_regions">statistic_regions</a>)
7571exactly the reverse holds: here <i>'w*pt*BC'</i> and <i>'wptBC'</i>
7572show very large errors and should not be used.<br>
7573
7574
7575
7576 <br>
7577
7578
7579
7580
7581This scheme is not allowed for non-cyclic lateral boundary conditions
7582(see <a href="#bc_lr">bc_lr</a>
7583and <a href="#bc_ns">bc_ns</a>).<br>
7584
7585
7586
7587 <br>
7588
7589
7590
7591
7592      </div>
7593
7594
7595
7596 <span style="font-style: italic;">'ups-scheme'</span><br>
7597
7598
7599
7600
7601     
7602     
7603     
7604      <p style="margin-left: 40px;">The upstream-spline-scheme
7605is used
7606(see Mahrer and Pielke,
76071978: Mon. Wea. Rev., 106, 818-830). In opposite to the Piascek
7608Williams scheme, this is characterized by much better numerical
7609features (less numerical diffusion, better preservation of flux
7610structures, e.g. vortices), but computationally it is much more
7611expensive. In
7612addition, the use of the Euler-timestep scheme is mandatory (<a href="#timestep_scheme">timestep_scheme</a>
7613= <span style="font-style: italic;">'</span><i>euler'</i>),
7614i.e. the
7615timestep accuracy is only first order. For this reason the advection of
7616momentum (see <a href="#momentum_advec">momentum_advec</a>)
7617should then also be carried out with the upstream-spline scheme,
7618because otherwise the momentum would
7619be subject to large numerical diffusion due to the upstream
7620scheme.&nbsp; </p>
7621
7622
7623
7624 
7625     
7626     
7627     
7628      <p style="margin-left: 40px;">Since
7629the cubic splines used tend
7630to overshoot under
7631certain circumstances, this effect must be adjusted by suitable
7632filtering and smoothing (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>,
7633      <a href="#long_filter_factor">long_filter_factor</a>,
7634      <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>).
7635This is always neccesssary for runs with stable stratification,
7636even if this stratification appears only in parts of the model
7637domain.&nbsp; </p>
7638
7639
7640
7641 
7642     
7643     
7644     
7645      <p style="margin-left: 40px;">With
7646stable stratification the
7647upstream-upline scheme also produces gravity waves with large
7648amplitude, which must be
7649suitably damped (see <a href="chapter_4.2.html#rayleigh_damping_factor">rayleigh_damping_factor</a>).<br>
7650
7651
7652
7653
7654      </p>
7655
7656
7657
7658 
7659     
7660     
7661     
7662      <p style="margin-left: 40px;"><span style="font-weight: bold;">Important: </span>The&nbsp;
7663upstream-spline scheme is not implemented for humidity and passive
7664scalars (see&nbsp;<a href="#humidity">humidity</a>
7665and <a href="#passive_scalar">passive_scalar</a>)
7666and requires the use of a 2d-domain-decomposition. The last conditions
7667severely restricts code optimization on several machines leading to
7668very long execution times! This scheme is also not allowed for
7669non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
7670and <a href="#bc_ns">bc_ns</a>).</p>
7671
7672
7673
7674      <br>
7675
7676
7677
7678A
7679differing advection scheme can be choosed for the subgrid-scale TKE
7680using parameter <a href="chapter_4.1.html#use_upstream_for_tke">use_upstream_for_tke</a>.</td>
7681
7682
7683
7684
7685    </tr>
7686
7687
7688
7689 <tr>
7690
7691
7692
7693 <td style="vertical-align: top;">
7694     
7695     
7696     
7697      <p><a name="statistic_regions"></a><b>statistic_regions</b></p>
7698
7699
7700
7701
7702      </td>
7703
7704
7705
7706 <td style="vertical-align: top;">I</td>
7707
7708
7709
7710
7711      <td style="vertical-align: top;"><i>0</i></td>
7712
7713
7714
7715
7716      <td style="vertical-align: top;"> 
7717     
7718     
7719     
7720      <p>Number of
7721additional user-defined subdomains for which
7722statistical analysis
7723and corresponding output (profiles, time series) shall be
7724made.&nbsp; </p>
7725
7726
7727
7728 
7729     
7730     
7731     
7732      <p>By default, vertical profiles and
7733other statistical quantities
7734are calculated as horizontal and/or volume average of the total model
7735domain. Beyond that, these calculations can also be carried out for
7736subdomains which can be defined using the field <a href="chapter_3.5.3.html">rmask </a>within the
7737user-defined software
7738(see <a href="chapter_3.5.3.html">chapter
77393.5.3</a>). The number of these subdomains is determined with the
7740parameter <b>statistic_regions</b>. Maximum 9 additional
7741subdomains
7742are allowed. The parameter <a href="chapter_4.3.html#region">region</a>
7743can be used to assigned names (identifier) to these subdomains which
7744are then used in the headers
7745of the output files and plots.</p>
7746
7747
7748
7749     
7750     
7751     
7752      <p>If the default NetCDF
7753output format is selected (see parameter <a href="chapter_4.2.html#data_output_format">data_output_format</a>),
7754data for the total domain and all defined subdomains are output to the
7755same file(s) (<a href="chapter_3.4.html#DATA_1D_PR_NETCDF">DATA_1D_PR_NETCDF</a>,
7756      <a href="chapter_3.4.html#DATA_1D_TS_NETCDF">DATA_1D_TS_NETCDF</a>).
7757In case of <span style="font-weight: bold;">statistic_regions</span>
7758&gt; <span style="font-style: italic;">0</span>,
7759data on the file for the different domains can be distinguished by a
7760suffix which is appended to the quantity names. Suffix 0 means data for
7761the total domain, suffix 1 means data for subdomain 1, etc.</p>
7762
7763
7764
7765     
7766     
7767     
7768      <p>In
7769case of <span style="font-weight: bold;">data_output_format</span>
7770= <span style="font-style: italic;">'profil'</span>,
7771individual local files for profiles (<a href="chapter_3.4.html#PLOT1D_DATA">PLOT1D_DATA</a>)&nbsp;are
7772created for each subdomain. The individual subdomain files differ by
7773their name (the
7774number of the respective subdomain is attached, e.g.
7775PLOT1D_DATA_1). In this case the name of the file with the data of
7776the total domain is PLOT1D_DATA_0. If no subdomains
7777are declared (<b>statistic_regions</b> = <i>0</i>),
7778the name
7779PLOT1D_DATA is used (this must be considered in the
7780respective file connection statements of the <span style="font-weight: bold;">mrun</span> configuration
7781file).</p>
7782
7783
7784
7785 </td>
7786
7787
7788
7789 </tr>
7790
7791
7792
7793 <tr>
7794
7795
7796
7797 <td style="vertical-align: top;"> 
7798     
7799     
7800     
7801      <p><a name="surface_heatflux"></a><b>surface_heatflux</b></p>
7802
7803
7804
7805
7806      </td>
7807
7808
7809
7810 <td style="vertical-align: top;">R</td>
7811
7812
7813
7814
7815      <td style="vertical-align: top;"><span style="font-style: italic;">no prescribed<br>
7816
7817
7818
7819
7820heatflux<br>
7821
7822
7823
7824 </span></td>
7825
7826
7827
7828 <td style="vertical-align: top;"> 
7829     
7830     
7831     
7832      <p>Kinematic sensible
7833heat flux at the bottom surface (in K m/s).&nbsp; </p>
7834
7835
7836
7837 
7838     
7839     
7840     
7841      <p>If
7842a value is assigned to this parameter, the internal two-dimensional
7843surface heat flux field <span style="font-style: italic;">shf</span>
7844is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>&nbsp;as
7845bottom (horizontally homogeneous) boundary condition for the
7846temperature equation. This additionally requires that a Neumann
7847condition must be used for the potential temperature (see <a href="#bc_pt_b">bc_pt_b</a>),
7848because otherwise the resolved scale may contribute to
7849the surface flux so that a constant value cannot be guaranteed. Also,
7850changes of the
7851surface temperature (see <a href="#pt_surface_initial_change">pt_surface_initial_change</a>)
7852are not allowed. The parameter <a href="#random_heatflux">random_heatflux</a>
7853can be used to impose random perturbations on the (homogeneous) surface
7854heat
7855flux field <span style="font-style: italic;">shf</span>.&nbsp;</p>
7856
7857
7858
7859
7860     
7861     
7862     
7863      <p>
7864In case of a non-flat <a href="#topography">topography</a>,&nbsp;the
7865internal two-dimensional&nbsp;surface heat
7866flux field <span style="font-style: italic;">shf</span>
7867is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>
7868at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
7869at the topography top face.&nbsp;The parameter<a href="#random_heatflux"> random_heatflux</a>
7870can be used to impose random perturbations on this combined surface
7871heat
7872flux field <span style="font-style: italic;">shf</span>.&nbsp;
7873      </p>
7874
7875
7876
7877 
7878     
7879     
7880     
7881      <p>If no surface heat flux is assigned, <span style="font-style: italic;">shf</span> is calculated
7882at each timestep by u<sub>*</sub> * theta<sub>*</sub>
7883(of course only with <a href="#prandtl_layer">prandtl_layer</a>
7884switched on). Here, u<sub>*</sub>
7885and theta<sub>*</sub> are calculated from the Prandtl law
7886assuming
7887logarithmic wind and temperature
7888profiles between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_pt_b">bc_pt_b</a>)
7889must be used as bottom boundary condition for the potential temperature.</p>
7890
7891
7892
7893     
7894     
7895     
7896      <p>See
7897also <a href="#top_heatflux">top_heatflux</a>.</p>
7898
7899
7900
7901
7902      </td>
7903
7904
7905
7906 </tr>
7907
7908
7909
7910 <tr>
7911
7912
7913
7914 <td style="vertical-align: top;"> 
7915     
7916     
7917     
7918      <p><a name="surface_pressure"></a><b>surface_pressure</b></p>
7919
7920
7921
7922
7923      </td>
7924
7925
7926
7927 <td style="vertical-align: top;">R</td>
7928
7929
7930
7931
7932      <td style="vertical-align: top;"><i>1013.25</i></td>
7933
7934
7935
7936
7937      <td style="vertical-align: top;"> 
7938     
7939     
7940     
7941      <p>Atmospheric
7942pressure at the surface (in hPa).&nbsp; </p>
7943
7944
7945
7946
7947Starting from this surface value, the vertical pressure
7948profile is calculated once at the beginning of the run assuming a
7949neutrally stratified
7950atmosphere. This is needed for
7951converting between the liquid water potential temperature and the
7952potential temperature (see <a href="#cloud_physics">cloud_physics</a><span style="text-decoration: underline;"></span>).</td>
7953
7954
7955
7956
7957    </tr>
7958
7959
7960
7961 <tr>
7962
7963
7964
7965 <td style="vertical-align: top;">
7966     
7967     
7968     
7969      <p><a name="surface_scalarflux"></a><b>surface_scalarflux</b></p>
7970
7971
7972
7973
7974      </td>
7975
7976
7977
7978 <td style="vertical-align: top;">R</td>
7979
7980
7981
7982
7983      <td style="vertical-align: top;"><i>0.0</i></td>
7984
7985
7986
7987
7988      <td style="vertical-align: top;"> 
7989     
7990     
7991     
7992      <p>Scalar flux at
7993the surface (in kg/(m<sup>2</sup> s)).&nbsp; &l