Home

Context Navigation

chapter_4.1.html @ 108

Last change on this file since 108 was 108, checked in by letzel, 17 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

Line
1	<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2	<html>
3	<head>
4
5
6
7
8
9
10
11	<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
12
13
14
15
16
17
18	<title>PALM chapter 4.1</title>
19	</head>
20
21
22	<body>
23
24
25
26	<h3><a name="chapter4.1"></a>4.1
27	Initialization 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
116	mixing length to the Prandtl-layer law.  </p>
117
118
119
120
121
122
123
124	<p>Usually
125	the mixing length in LES models l<sub>LES</sub>
126	depends (as in PALM) on the grid size and is possibly restricted
127	further in case of stable stratification and near the lower wall (see
128	parameter <a href="#wall_adjustment">wall_adjustment</a>).
129	With <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span>
130	the Prandtl' mixing length l<sub>PR</sub> = kappa * z/phi
131	is calculated
132	and the mixing length actually used in the model is set l = MIN (l<sub>LES</sub>,
133	l<sub>PR</sub>). This usually gives a decrease of the
134	mixing length at
135	the bottom boundary and considers the fact that eddy sizes
136	decrease in the vicinity of the wall.  </p>
137
138
139
140
141
142
143
144	<p style="font-style: normal;"><b>Warning:</b> So
145	far, there is
146	no good experience with <b>adjust_mixing_length</b> = <span style="font-style: italic;">.T.</span> !  </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
155	Prandtl-layer being
156	switched on (see <a href="#prandtl_layer">prandtl_layer</a>)
157	<span style="font-style: italic;">'(u)* 2+neumann'</span>
158	should always be set as the lower boundary condition for the TKE (see <a href="#bc_e_b">bc_e_b</a>),
159	otherwise the near-surface value of the TKE is not in agreement with
160	the Prandtl-layer law (Prandtl-layer law and Prandtl-Kolmogorov-Ansatz
161	should provide the same value for K<sub>m</sub>). A warning
162	is given,
163	if 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
216	with respect to the horizontal (in degrees).  </p>
217
218
219
220
221
222
223
224	<p style="font-style: normal;">By means of <b>alpha_surface</b>
225	the model domain can be inclined in x-direction with respect to the
226	horizontal. In this way flows over inclined surfaces (e.g. drainage
227	flows, gravity flows) can be simulated. In case of <b>alpha_surface
228	</b>/= <span style="font-style: italic;">0</span>
229	the buoyancy term
230	appears both in
231	the 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
245	is only possible in
246	case of cyclic horizontal boundary conditions along x AND y (see <a href="#bc_lr">bc_lr</a>
247	and <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
256	user-defined code as well as modifications to the default code. Please
257	ask the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/PALM_group.html#0">PALM
258	developer  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
302	TKE.  </p>
303
304
305
306
307
308
309
310	<p><b>bc_e_b</b> may be
311	set to <span style="font-style: italic;">'neumann'</span>
312	or <span style="font-style: italic;">'(u) * 2+neumann'</span>.
313	<b>bc_e_b</b>
314	= <span style="font-style: italic;">'neumann'</span>
315	yields to
316	e(k=0)=e(k=1) (Neumann boundary condition), where e(k=1) is calculated
317	via the prognostic TKE equation. Choice of <span style="font-style: italic;">'(u)*2+neumann'</span>
318	also yields to
319	e(k=0)=e(k=1), but the TKE at the Prandtl-layer top (k=1) is calculated
320	diagnostically by e(k=1)=(us/0.1)**2. However, this is only allowed if
321	a Prandtl-layer is used (<a href="#prandtl_layer">prandtl_layer</a>).
322	If this is not the case, a warning is given and <b>bc_e_b</b>
323	is reset
324	to <span style="font-style: italic;">'neumann'</span>.
325	</p>
326
327
328
329
330
331
332
333	<p style="font-style: normal;">At the top
334	boundary a Neumann
335	boundary 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
376	condition along x (for all quantities).<br>
377
378
379
380	<br>
381
382
383
384
385	By 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
395	also be
396	assigned 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
399	right, outflow to the left). This requires the multi-grid method to be
400	used 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>)
401	and it also requires cyclic boundary conditions along y (see <a href="#bc_ns">bc_ns</a>).<br>
402
403
404
405	<br>
406
407
408
409
410	In case of these non-cyclic lateral boundaries, a Dirichlet condition
411	is used at the inflow for all quantities (initial vertical profiles -
412	see <a href="#initializing_actions">initializing_actions</a>
413	- are fixed during the run) except u, to which a Neumann (zero
414	gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
415	gradient) condition is used for the scalars. For perturbation
416	pressure Neumann (zero gradient) conditions are assumed both at the
417	inflow and at the outflow.<br>
418
419
420
421	<br>
422
423
424
425
426	When using non-cyclic lateral boundaries, a filter is applied to the
427	velocity field in the vicinity of the outflow in order to suppress any
428	reflections of outgoing disturbances (see <a href="#km_damp_max">km_damp_max</a>
429	and <a href="#outflow_damping_width">outflow_damping_width</a>).<br>
430
431
432
433
434	<br>
435
436
437
438
439	In order to maintain a turbulent state of the flow, it may be
440	neccessary to continuously impose perturbations on the horizontal
441	velocity field in the vicinity of the inflow throughout the whole run.
442	This 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>.
443	The horizontal range to which these perturbations are applied is
444	controlled by the parameters <a href="#inflow_disturbance_begin">inflow_disturbance_begin</a>
445	and <a href="#inflow_disturbance_end">inflow_disturbance_end</a>.
446	The 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>,
448	and <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM_group/doc/app/chapter_4.2.html#psolver">disturbance_amplitude</a>.
449	The 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
459	In 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
460	at_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
473	Using non-cyclic lateral boundaries requires very sensitive adjustments
474	of the inflow (vertical profiles) and the bottom boundary conditions,
475	e.g. a surface heating should not be applied near the inflow boundary
476	because this may significantly disturb the inflow. Please check the
477	model 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
513	condition along y (for all quantities).<br>
514
515
516
517	<br>
518
519
520
521
522	By 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
532	also be
533	assigned 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
536	requires the multi-grid
537	method to be used for solving the Poisson equation for perturbation
538	pressure (see <a href="chapter_4.2.html#psolver">psolver</a>)
539	and 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
552	In case of these non-cyclic lateral boundaries, a Dirichlet condition
553	is used at the inflow for all quantities (initial vertical profiles -
554	see <a href="chapter_4.1.html#initializing_actions">initializing_actions</a>
555	- are fixed during the run) except u, to which a Neumann (zero
556	gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero
557	gradient) condition is used for the scalars. For perturbation
558	pressure Neumann (zero gradient) conditions are assumed both at the
559	inflow and at the outflow.<br>
560
561
562
563	<br>
564
565
566
567
568	For further details regarding non-cyclic lateral boundary conditions
569	see <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
609	perturbation pressure.  </p>
610
611
612
613
614
615
616
617	<p>Allowed values
618	are <span style="font-style: italic;">'dirichlet'</span>,
619	<span style="font-style: italic;">'neumann'</span>
620	and <span style="font-style: italic;">'neumann+inhomo'</span>.
621	<span style="font-style: italic;">'dirichlet'</span>
622	sets
623	p(k=0)=0.0,  <span style="font-style: italic;">'neumann'</span>
624	sets p(k=0)=p(k=1). <span style="font-style: italic;">'neumann+inhomo'</span>
625	corresponds to an extended Neumann boundary condition where heat flux
626	or temperature inhomogeneities near the
627	surface (pt(k=1))  are additionally regarded (see Shen and
628	LeClerc
629	(1995, Q.J.R. Meteorol. Soc.,
630	1209)). This condition is only permitted with the Prandtl-layer
631	switched on (<a href="#prandtl_layer">prandtl_layer</a>),
632	otherwise the run is terminated.  </p>
633
634
635
636
637
638
639
640	<p>Since
641	at the bottom boundary of the model the vertical
642	velocity
643	disappears (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>)
644	dp/dz = 0 should
645	be used, which leaves the vertical component w unchanged when the
646	pressure solver is applied. Simultaneous use of the Neumann boundary
647	conditions both at the bottom and at the top boundary (<a href="#bc_p_t">bc_p_t</a>)
648	usually yields no consistent solution for the perturbation pressure and
649	should 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
693	perturbation pressure.  </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)).  </p>
704
705
706
707
708
709
710
711	<p>Simultaneous use
712	of Neumann boundary conditions both at the
713	top and bottom boundary (<a href="#bc_p_b">bc_p_b</a>)
714	usually yields no consistent solution for the perturbation pressure and
715	should be avoided. Since at the bottom boundary the Neumann
716	condition  is a good choice (see <a href="#bc_p_b">bc_p_b</a>),
717	a 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
762	potential temperature.  </p>
763
764
765
766
767
768
769
770	<p>Allowed values
771	are <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>;
774	the user may change this value during the run using user-defined code)
775	and <span style="font-style: italic;">'neumann'</span>
776	(pt(k=0)=pt(k=1)).  <br>
777
778
779
780
781	When 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>
783	must be used, because otherwise the resolved scale may contribute to
784	the 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, <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
836	potential temperature.  </p>
837
838
839
840
841
842
843
844	<p>Allowed are the
845	values <span style="font-style: italic;">'dirichlet' </span>(pt(k=nz+1)
846	does 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>.
848	With the 'initial_gradient'-condition the value of the temperature
849	gradient at the top is
850	calculated from the initial
851	temperature profile (see <a href="#pt_surface">pt_surface</a>,
852	<a href="#pt_vertical_gradient">pt_vertical_gradient</a>)
853	by bc_pt_t_val = (pt_init(k=nz+1) -
854	pt_init(k=nz)) / dzu(nz+1).<br>
855
856
857
858
859	Using this value (assumed constant during the
860	run) the temperature boundary values are calculated as  </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) =
877	pt(k=nz) +
878	bc_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
895	equation for the temperature is solved).<br>
896
897
898
899
900	When 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>
902	must be used, because otherwise the resolved scale may contribute to
903	the 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
948	specific humidity / total water content.  </p>
949
950
951
952
953
954
955
956	<p>Allowed
957	values 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>;
960	the user may change this value during the run using user-defined code)
961	and <span style="font-style: italic;">'neumann'</span>
962	(q(k=0)=q(k=1)).  <br>
963
964
965
966
967	When 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>
969	must be used, because otherwise the resolved scale may contribute to
970	the 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
1015	specific humidity / total water content.  </p>
1016
1017
1018
1019
1020
1021
1022
1023	<p>Allowed
1024	are the values <span style="font-style: italic;">'dirichlet'</span>
1025	(q(k=nz) and q(k=nz+1) do
1026	not change during the run) and <span style="font-style: italic;">'neumann'</span>.
1027	With the Neumann boundary
1028	condition the value of the humidity gradient at the top is calculated
1029	from the
1030	initial humidity profile (see <a href="#q_surface">q_surface</a>,
1031	<a href="#q_vertical_gradient">q_vertical_gradient</a>)
1032	by: bc_q_t_val = ( q_init(k=nz) - q_init(k=nz-1)) / dzu(nz).<br>
1033
1034
1035
1036
1037	Using this value (assumed constant during the run) the humidity
1038	boundary values
1039	are calculated as  </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) +
1056	bc_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
1073	equation 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
1117	scalar concentration.  </p>
1118
1119
1120
1121
1122
1123
1124
1125	<p>Allowed values
1126	are <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>;
1129	the user may change this value during the run using user-defined code)
1130	and <span style="font-style: italic;">'neumann'</span>
1131	(s(k=0) =
1132	s(k=1)).  <br>
1133
1134
1135
1136
1137	When 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>
1139	must be used, because otherwise the resolved scale may contribute to
1140	the 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
1185	scalar concentration.  </p>
1186
1187
1188
1189
1190
1191
1192
1193	<p>Allowed are the
1194	values <span style="font-style: italic;">'dirichlet'</span>
1195	(s(k=nz) and s(k=nz+1) do
1196	not change during the run) and <span style="font-style: italic;">'neumann'</span>.
1197	With the Neumann boundary
1198	condition the value of the scalar concentration gradient at the top is
1199	calculated
1200	from the initial scalar concentration profile (see <a href="#s_surface">s_surface</a>, <a href="#s_vertical_gradient">s_vertical_gradient</a>)
1201	by: bc_s_t_val = (s_init(k=nz) - s_init(k=nz-1)) / dzu(nz).<br>
1202
1203
1204
1205
1206	Using this value (assumed constant during the run) the concentration
1207	boundary values
1208	are 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) +
1225	bc_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
1242	equation for the scalar concentration is
1243	solved).</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.  </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
1291	values <span style="font-style: italic;">'dirichlet' </span>(sa(k=nz+1)
1292	does 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>. <br>
1294
1295
1296
1297	<br>
1298
1299
1300
1301
1302	When 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>
1304	must be used, because otherwise the resolved scale may contribute to
1305	the 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
1349	horizontal velocity components u and v.  </p>
1350
1351
1352
1353
1354
1355
1356
1357	<p>Allowed
1358	values 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>
1361	yields the
1362	no-slip condition with u=v=0 at the bottom. Due to the staggered grid
1363	u(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 *
1365	dz. u=v=0 at the bottom is guaranteed using mirror boundary
1366	condition:  </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) = -
1383	v(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
1400	Neumann boundary condition
1401	yields the free-slip condition with u(k=0) = u(k=1) and v(k=0) =
1402	v(k=1).
1403	With Prandtl - layer switched on, the free-slip condition is not
1404	allowed (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
1449	horizontal velocity components u and v.  </p>
1450
1451
1452
1453
1454
1455
1456
1457	<p>Allowed
1458	values are <span style="font-style: italic;">'dirichlet'</span>
1459	and <span style="font-style: italic;">'neumann'</span>.
1460	The
1461	Dirichlet condition yields u(k=nz+1) = ug(nz+1) and v(k=nz+1) =
1462	vg(nz+1),
1463	Neumann condition yields the free-slip condition with u(k=nz+1) =
1464	u(k=nz) and v(k=nz+1) = v(k=nz) (up to k=nz the prognostic equations
1465	for 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> 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). </p>
1505
1506
1507
1508	This 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
1513	respective salinity flux value is used
1514	as bottom (horizontally homogeneous) boundary condition for the salinity equation. This additionally requires that a Neumann
1515	condition 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
1550	of a single building in m.<br>
1551
1552
1553
1554	<br>
1555
1556
1557
1558	<span style="font-weight: bold;">building_height</span> must
1559	be less than the height of the model domain. This parameter requires
1560	the use of <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
1588	building in m.<br>
1589
1590
1591
1592	<br>
1593
1594
1595
1596
1597	Currently, <span style="font-weight: bold;">building_length_x</span>
1598	must be at least <span style="font-style: italic;">3
1599	* </span><a style="font-style: italic;" href="#dx">dx</a> and no more than <span style="font-style: italic;">( </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>.
1601	This parameter requires the use of <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
1629	of a single building in m.<br>
1630
1631
1632
1633	<br>
1634
1635
1636
1637
1638	Currently, <span style="font-weight: bold;">building_length_y</span>
1639	must be at least <span style="font-style: italic;">3
1640	* </span><a style="font-style: italic;" href="#dy">dy</a> and no more than <span style="font-style: italic;">( </span><a style="font-style: italic;" href="#ny">ny</a><span style="font-style: italic;"> - 1 ) </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
1641	the use of <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
1670	left building wall and the left border of the model domain) in m.<br>
1671
1672
1673
1674
1675	<br>
1676
1677
1678
1679
1680	Currently, <span style="font-weight: bold;">building_wall_left</span>
1681	must be at least <span style="font-style: italic;">1
1682	* </span><a style="font-style: italic;" href="#dx">dx</a> and less than <span style="font-style: italic;">( <a href="#nx">nx</a>
1683	- 1 ) * <a href="#dx">dx</a> -  <a href="#building_length_x">building_length_x</a></span>.
1684	This parameter requires the use of <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
1695	The default value <span style="font-weight: bold;">building_wall_left</span>
1696	= <span style="font-style: italic;">( ( <a href="#nx">nx</a> +
1697	1 ) * <a href="#dx">dx</a> -  <a href="#building_length_x">building_length_x</a> ) / 2</span>
1698	centers 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
1726	South building wall and the South border of the model domain) in m.<br>
1727
1728
1729
1730
1731	<br>
1732
1733
1734
1735
1736	Currently, <span style="font-weight: bold;">building_wall_south</span>
1737	must be at least <span style="font-style: italic;">1
1738	* </span><a style="font-style: italic;" href="#dy">dy</a> and less than <span style="font-style: italic;">( <a href="#ny">ny</a>
1739	- 1 ) * <a href="#dy">dy</a> -  <a href="#building_length_y">building_length_y</a></span>.
1740	This parameter requires the use of <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
1751	The default value <span style="font-weight: bold;">building_wall_south</span>
1752	= <span style="font-style: italic;">( ( <a href="#ny">ny</a> +
1753	1 ) * <a href="#dy">dy</a> -  <a href="#building_length_y">building_length_y</a> ) / 2</span>
1754	centers 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
1795	usage of cloud droplets.<br>
1796
1797
1798
1799	<br>
1800
1801
1802
1803
1804	Cloud droplets require to use the particle package (<span style="font-weight: bold;">mrun</span>-option <span style="font-family: monospace;">-p particles</span>),
1805	so in this case a particle corresponds to a droplet. The droplet
1806	features (number of droplets, initial radius, etc.) can be steered with
1807	the  respective particle parameters (see e.g. <a href="#chapter_4.2.html#radius">radius</a>).
1808	The real number of initial droplets in a grid cell is equal to the
1809	initial 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>)
1812	times the <a href="#initial_weighting_factor">initial_weighting_factor</a>.<br>
1813
1814
1815
1816
1817	<br>
1818
1819
1820
1821
1822	In case of using cloud droplets, the default condensation scheme in
1823	PALM cannot be used, i.e. <a href="#cloud_physics">cloud_physics</a>
1824	must 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
1872	on the condensation scheme.  </p>
1873
1874
1875
1876
1877	For <b>cloud_physics =</b> <span style="font-style: italic;">.TRUE.</span>, equations
1878	for the
1879	liquid water
1880	content and the liquid water potential temperature are solved instead
1881	of those for specific humidity and potential temperature. Note
1882	that a grid volume is assumed to be either completely saturated or
1883	completely
1884	unsaturated (0%-or-100%-scheme). A simple precipitation scheme can
1885	additionally be switched on with parameter <a href="#precipitation">precipitation</a>.
1886	Also 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
1895	cloud_physics =</b> <span style="font-style: italic;">.TRUE.
1896	</span>requires <a href="#humidity">humidity</a>
1897	=<span style="font-style: italic;"> .TRUE.</span> .<br>
1898
1899
1900
1901
1902	Detailed information about the condensation scheme is given in the
1903	description of the <a href="http://www.muk.uni-hannover.de/%7Eraasch/PALM-1/Dokumentationen/Cloud_physics/wolken.pdf">cloud
1904	physics module</a> (pdf-file, only in German).<br>
1905
1906
1907
1908	<br>
1909
1910
1911
1912
1913	This condensation scheme is not allowed if cloud droplets are simulated
1914	explicitly (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
1945	of 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>
1955	guarantees that the volume flow through the xz- or yz-cross-section of
1956	the total model domain remains constant (equal to the initial value at
1957	t=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
2001	so-called overshoots, which can occur with the
2002	upstream-spline scheme.  </p>
2003
2004
2005
2006
2007
2008
2009
2010	<p><font color="#000000">The cubic splines tend to overshoot in
2011	case of discontinuous changes of variables between neighbouring grid
2012	points.</font><font color="#ff0000"> </font><font color="#000000">This
2013	may lead to errors in calculating the advection tendency.</font>
2014	Choice
2015	of <b>cut_spline_overshoot</b> = <i>.TRUE.</i>
2016	(switched on by
2017	default)
2018	allows variable values not to exceed an interval defined by the
2019	respective adjacent grid points. This interval can be adjusted
2020	seperately 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>,
2022	etc.). This might be necessary in case that the
2023	default interval has a non-tolerable effect on the model
2024	results.  </p>
2025
2026
2027
2028
2029
2030
2031
2032	<p>Overshoots may also be removed
2033	using the parameters <a href="#ups_limit_e">ups_limit_e</a>,
2034	<a href="#ups_limit_pt">ups_limit_pt</a>,
2035	etc. 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
2080	the damping layer begins in the 1d-model
2081	(in m).  </p>
2082
2083
2084
2085
2086
2087
2088
2089	<p>This parameter is used to
2090	switch on a damping layer for the
2091	1d-model, which is generally needed for the damping of inertia
2092	oscillations. Damping is done by gradually increasing the value
2093	of the eddy diffusivities about 10% per vertical grid level
2094	(starting with the value at the height given by <b>damp_level_1d</b>,
2095	or possibly from the next grid pint above), i.e. K<sub>m</sub>(k+1)
2096	=
2097	1.1 * K<sub>m</sub>(k).
2098	The values of K<sub>m</sub> are limited to 10 m**2/s at
2099	maximum.  <br>
2100
2101
2102
2103
2104	This parameter only comes into effect if the 1d-model is switched on
2105	for
2106	the 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
2160	the energy dissipation term in the TKE equation of the 1d-model.<br>
2161
2162
2163
2164
2165	<br>
2166
2167
2168
2169
2170	By 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
2180	Setting <span style="font-weight: bold;">dissipation_1d</span>
2181	= <span style="font-style: italic;">'detering'</span>
2182	forces 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
2227	the 3d-model (in s).  </p>
2228
2229
2230
2231
2232
2233
2234
2235	<p>By default, (i.e.
2236	if a Runge-Kutta scheme is used, see <a href="#timestep_scheme">timestep_scheme</a>)
2237	the value of the time step is calculating after each time step
2238	(following the time step criteria) and
2239	used for the next step.</p>
2240
2241
2242
2243
2244
2245
2246
2247	<p>If the user assigns <b>dt</b>
2248	a value, then the time step is
2249	fixed to this value throughout the whole run (whether it fulfills the
2250	time step
2251	criteria or not). However, changes are allowed for restart runs,
2252	because <b>dt</b> can also be used as a <a href="chapter_4.2.html#dt_laufparameter">run
2253	parameter</a>.  </p>
2254
2255
2256
2257
2258
2259
2260
2261	<p>In case that the
2262	calculated 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> < 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
2300	aborted. Such situations usually arise
2301	in case of any numerical problem / instability which causes a
2302	non-realistic increase of the wind speed.  </p>
2303
2304
2305
2306
2307
2308
2309
2310	<p>A
2311	small time step due to a large mean horizontal windspeed
2312	speed may be enlarged by using a coordinate transformation (see <a href="#galilei_transformation">galilei_transformation</a>),
2313	in order to spare CPU time.<br>
2314
2315
2316
2317	</p>
2318
2319
2320
2321
2322
2323
2324
2325	<p>If the
2326	leapfrog timestep scheme is used (see <a href="#timestep_scheme">timestep_scheme</a>)
2327	a 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
2329	diffusion condition. Next it is examined whether dt_new exceeds or
2330	falls below the
2331	value of the previous timestep by at
2332	least +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,
2334	then <span style="font-weight: bold;">dt </span>=
2335	1.02 * dt_prev
2336	(previous timestep) is used as the new timestep, however the time
2337	step is only increased if the last change of the time step is dated
2338	back at
2339	least 30 iterations. If dt_new is located in the interval mentioned
2340	above, then dt
2341	does not change at all. By doing so, permanent time step changes as
2342	well as large
2343	sudden 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
2388	interval of vertical profile output of the 1D-model
2389	(in s).  </p>
2390
2391
2392
2393
2394
2395
2396
2397	<p>Data are written in ASCII
2398	format to file <a href="chapter_3.4.html#LIST_PROFIL_1D">LIST_PROFIL_1D</a>.
2399	This parameter is only in effect if the 1d-model has been switched on
2400	for the
2401	initialization 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
2446	runtime control output of the 1d-model
2447	(in s).  </p>
2448
2449
2450
2451
2452
2453
2454
2455	<p>Data are written in ASCII
2456	format to file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.
2457	This parameter is only in effect if the 1d-model is switched on for the
2458	initialization 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
2503	spacing along the x-direction (in m).  </p>
2504
2505
2506
2507
2508
2509
2510
2511	<p>Along
2512	x-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 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>
2520	and <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
2564	spacing along the y-direction (in m).  </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 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>
2580	and <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
2628	spacing (in m).  </p>
2629
2630
2631
2632
2633
2634
2635
2636	<p>This parameter must be
2637	assigned by the user, because no
2638	default value is given.<br>
2639
2640
2641
2642	</p>
2643
2644
2645
2646
2647
2648
2649
2650	<p>By default, the
2651	model uses constant grid spacing along z-direction, but it can be
2652	stretched using the parameters <a href="#dz_stretch_level">dz_stretch_level</a>
2653	and <a href="#dz_stretch_factor">dz_stretch_factor</a>.
2654	In 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
2667	a constant <span style="font-weight: bold;">dz</span>,
2668	the scalar levels (zu) are calculated directly by:  </p>
2669
2670
2671
2672
2673
2674
2675
2676	<ul>
2677
2678
2679
2680
2681
2682
2683
2684	<p>zu(0) = - dz * 0.5  <br>
2685
2686
2687
2688
2689	zu(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
2706	half between them:  </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
2761	spacing (in m).<br>
2762
2763
2764
2765	<br>
2766
2767
2768
2769	If the vertical grid is stretched
2770	(see <a href="#dz_stretch_factor">dz_stretch_factor</a>
2771	and <a href="#dz_stretch_level">dz_stretch_level</a>),
2772	<span style="font-weight: bold;">dz_max</span> can
2773	be 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
2813	vertically stretched grid (see <a href="#dz_stretch_level">dz_stretch_level</a>).
2814	</p>
2815
2816
2817
2818
2819
2820
2821
2822	<p>The stretch factor should not exceed a value of
2823	approx. 1.10 -
2824	1.12, otherwise the discretization errors due to the stretched grid not
2825	negligible 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
2874	above/below which the grid is to be stretched
2875	vertically (in m).  </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) <span style="font-weight: bold;">above </span>which the grid is to be stretched
2884	vertically. The vertical grid
2885	spacings <a href="#dz">dz</a>
2886	above this level are calculated as  </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).
2920	The
2921	w-levels are then defined as:  </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
2949	vertically. The vertical grid
2950	spacings <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
2998	This
2999	option prescribes an initial 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 <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
3023	subgrid-scale TKE in m<sup>2</sup>s<sup>-2</sup>.<br>
3024
3025
3026
3027
3028	<br>
3029
3030
3031
3032	This
3033	option adds artificial viscosity to the flow by ensuring that
3034	the
3035	subgrid-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
3080	simulated for the 1d-model (in s).  </p>
3081
3082
3083
3084
3085
3086
3087
3088	<p>The
3089	default value corresponds to a simulated time of 10 days.
3090	Usually, after such a period the inertia oscillations have completely
3091	decayed and the solution of the 1d-model can be regarded as stationary
3092	(see <a href="#damp_level_1d">damp_level_1d</a>).
3093	This parameter is only in effect if the 1d-model is switched on for the
3094	initialization 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
3144	be used.<br>
3145
3146
3147
3148	</p>
3149
3150
3151
3152
3153
3154
3155
3156	<p><br>
3157
3158
3159
3160
3161	The fast fourier transformation (FFT) is used for solving the
3162	perturbation pressure equation with a direct method (see <a href="chapter_4.2.html#psolver">psolver</a>)
3163	and for calculating power spectra (see optional software packages,
3164	section <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
3177	By default, system-specific, optimized routines from external
3178	vendor libraries are used. However, these are available only on certain
3179	computers and there are more or less severe restrictions concerning the
3180	number of gridpoints to be used with them.<br>
3181
3182
3183
3184	</p>
3185
3186
3187
3188
3189
3190
3191
3192	<p>There
3193	are two other PALM internal methods available on every
3194	machine (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
3203	from Clive Temperton (ECWMF) which is computationally very fast and
3204	switched on with <b>fft_method</b> = <span style="font-style: italic;">'temperton-algorithm'</span>.
3205	The number of horizontal gridpoints (nx+1, ny+1) to be used with this
3206	method must be composed of prime factors 2, 3 and 5.<br>
3207
3208
3209
3210	</p>
3211
3212
3213
3214
3215	2.: The <span style="font-weight: bold;">Singleton</span>-method
3216	which is very slow but has no restrictions concerning the number of
3217	gridpoints 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
3255	Galilei-transformation to the
3256	coordinate
3257	system of the model.<br>
3258
3259
3260
3261
3262
3263
3264	<p>With <b>galilei_transformation</b>
3265	= <i>.T.,</i> a so-called
3266	Galilei-transformation is switched on which ensures that the coordinate
3267	system of the model is moved along with the geostrophical wind.
3268	Alternatively, the model domain can be moved along with the averaged
3269	horizontal wind (see <a href="#use_ug_for_galilei_tr">use_ug_for_galilei_tr</a>,
3270	this can and will naturally change in time). With this method,
3271	numerical inaccuracies of the Piascek - Williams - scheme (concerns in
3272	particular the momentum advection) are minimized. Beyond that, in the
3273	majority of cases the lower relative velocities in the moved system
3274	permit a larger time step (<a href="#dt">dt</a>).
3275	Switching the transformation on is only worthwhile if the geostrophical
3276	wind (ug, vg)
3277	and the averaged horizontal wind clearly deviate from the value 0. In
3278	each case, the distance the coordinate system has been moved is written
3279	to the file <a href="chapter_3.4.html#RUN_CONTROL">RUN_CONTROL</a>.
3280	</p>
3281
3282
3283
3284
3285
3286
3287
3288	<p>Non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
3289	and <a href="#bc_ns">bc_ns</a>), the specification
3290	of a gestrophic
3291	wind that is not constant with height
3292	as well as e.g. stationary inhomogeneities at the bottom boundary do
3293	not 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
3333	subdomain
3334	sizes in parallel runs.<br>
3335
3336
3337
3338	<br>
3339
3340
3341
3342
3343	For <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>,
3344	the subdomains are forced to have an identical
3345	size on all processors. In this case the processor numbers in the
3346	respective directions of the virtual processor net must fulfill certain
3347	divisor conditions concerning the grid point numbers in the three
3348	directions (see <a href="#nx">nx</a>, <a href="#ny">ny</a>
3349	and <a href="#nz">nz</a>).
3350	Advantage of this method is that all PEs bear the same computational
3351	load.<br>
3352
3353
3354
3355	<br>
3356
3357
3358
3359
3360	There is no such restriction by default, because then smaller
3361	subdomains are allowed on those processors which
3362	form the right and/or north boundary of the virtual processor grid. On
3363	all other processors the subdomains are of same size. Whether smaller
3364	subdomains are actually used, depends on the number of processors and
3365	the grid point numbers used. Information about the respective settings
3366	are 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
3376	When 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>)
3377	only <b>grid_matching</b> = <span style="font-style: italic;">'strict'</span>
3378	is allowed.<br>
3379
3380
3381
3382	<br>
3383
3384
3385
3386	<b>Note:</b><br>
3387
3388
3389
3390
3391	In some cases for small processor numbers there may be a very bad load
3392	balancing among the
3393	processors 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
3411	begin</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
3430	limit of the horizontal range for which random perturbations are to be
3431	imposed on the horizontal velocity field (gridpoints).<br>
3432
3433
3434
3435	<br>
3436
3437
3438
3439
3440	If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
3441	or <a href="#bc_ns">bc_ns</a>),
3442	this parameter gives the gridpoint number (counted horizontally from
3443	the inflow)  from which on perturbations are imposed on the
3444	horizontal velocity field. Perturbations must be switched on with
3445	parameter <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
3463	end</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
3485	limit of the horizontal range for which random perturbations are
3486	to be imposed on the horizontal velocity field (gridpoints).<br>
3487
3488
3489
3490	<br>
3491
3492
3493
3494
3495	If non-cyclic lateral boundary conditions are used (see <a href="#bc_lr">bc_lr</a>
3496	or <a href="#bc_ns">bc_ns</a>),
3497	this parameter gives the gridpoint number (counted horizontally from
3498	the inflow)  unto which perturbations are imposed on the
3499	horizontal
3500	velocity 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
3544	to be carried out.  </p>
3545
3546
3547
3548
3549
3550
3551
3552	<p style="font-style: normal;">This parameter does not have a
3553	default value and therefore must be assigned with each model run. For
3554	restart runs <b>initializing_actions</b> = <span style="font-style: italic;">'read_restart_data'</span>
3555	must be set. For the initial run of a job chain the following values
3556	are allowed:  </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
3582	of 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>
3585	and <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>,
3587	respectively) as well as a vertical temperature (humidity) profile
3588	consisting of
3589	linear 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>
3592	and <a href="#q_vertical_gradient">q_vertical_gradient</a>)
3593	are assumed as initial profiles. The subgrid-scale TKE is set to 0 but K<sub>m</sub>
3594	and K<sub>h</sub> are set to very small values because
3595	otherwise no TKE
3596	would 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
3629	the
3630	(stationary) solution of the 1d-model. These are the variables e, kh,
3631	km, u, v and with Prandtl layer switched on rif, us, usws, vsws. The
3632	temperature (humidity) profile consisting of linear sections is set as
3633	for 'set_constant_profiles' and assumed as constant in time within the
3634	1d-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>)
3637	is 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
3661	of the 3d-model is under complete control of the user and has to be
3662	done in routine <a href="chapter_3.5.1.html#user_init_3d_model">user_init_3d_model</a>
3663	of 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
3680	velocity field of the
3681	3d-model corresponds to a
3682	Rankine-vortex with vertical axis. This setting may be used to test
3683	advection 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>)
3684	are necessary. In order not to distort the vortex, an initial
3685	horizontal wind profile constant
3686	with height is necessary (to be set by <b>initializing_actions</b>
3687	= <span style="font-style: italic;">'set_constant_profiles'</span>)
3688	and some other conditions have to be met (neutral stratification,
3689	diffusion must be
3690	switched off, see <a href="#km_constant">km_constant</a>).
3691	The center of the vortex is located at jc = (nx+1)/2. It
3692	extends from k = 0 to k = nz+1. Its radius is 8 * <a href="#dx">dx</a>
3693	and 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
3721	initial temperature field with radius 10.0 * <a href="#dx">dx</a>
3722	and center at jc = (nx+1)/2. This may be used for tests of scalar
3723	advection schemes
3724	(see <a href="#scalar_advec">scalar_advec</a>).
3725	Such tests require a horizontal wind profile constant with hight and
3726	diffusion
3727	switched off (see <span style="font-style: italic;">'initialize_vortex'</span>).
3728	Additionally, the buoyancy term
3729	must be switched of in the equation of motion  for w (this
3730	requires the user to comment out the call of <span style="font-family: monospace;">buoyancy</span> in the
3731	source 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
3748	combined, e.g. <b>initializing_actions</b> = <span style="font-style: italic;">'set_constant_profiles
3749	initialize_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>
3752	must 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
3809	diffusivities are used (laminar
3810	simulations).  </p>
3811
3812
3813
3814
3815
3816
3817
3818	<p>If this parameter is
3819	specified, both in the 1d and in the
3820	3d-model constant values for the eddy diffusivities are used in
3821	space and time with K<sub>m</sub> = <b>km_constant</b>
3822	and K<sub>h</sub> = K<sub>m</sub> / <a href="chapter_4.2.html#prandtl_number">prandtl_number</a>.
3823	The prognostic equation for the subgrid-scale TKE is switched off.
3824	Constant eddy diffusivities are only allowed with the Prandtl layer (<a href="#prandtl_layer">prandtl_layer</a>)
3825	switched 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
3860	or dy)</span></td>
3861
3862
3863
3864	<td style="vertical-align: top;">Maximum
3865	diffusivity used for filtering the velocity field in the vicinity of
3866	the outflow (in m<sup>2</sup>/s).<br>
3867
3868
3869
3870	<br>
3871
3872
3873
3874
3875	When using non-cyclic lateral boundaries (see <a href="#bc_lr">bc_lr</a>
3876	or <a href="#bc_ns">bc_ns</a>),
3877	a smoothing has to be applied to the
3878	velocity field in the vicinity of the outflow in order to suppress any
3879	reflections of outgoing disturbances. Smoothing is done by increasing
3880	the eddy diffusivity along the horizontal direction which is
3881	perpendicular to the outflow boundary. Only velocity components
3882	parallel to the outflow boundary are filtered (e.g. v and w, if the
3883	outflow is along x). Damping is applied from the bottom to the top of
3884	the domain.<br>
3885
3886
3887
3888	<br>
3889
3890
3891
3892
3893	The horizontal range of the smoothing is controlled by <a href="#outflow_damping_width">outflow_damping_width</a>
3894	which defines the number of gridpoints (counted from the outflow
3895	boundary) from where on the smoothing is applied. Starting from that
3896	point, the eddy diffusivity is linearly increased (from zero to its
3897	maximum value given by <span style="font-weight: bold;">km_damp_max</span>)
3898	until half of the damping range width, from where it remains constant
3899	up to the outflow boundary. If at a certain grid point the eddy
3900	diffusivity calculated from the flow field is larger than as described
3901	above, it is used instead.<br>
3902
3903
3904
3905	<br>
3906
3907
3908
3909
3910	The default value of <span style="font-weight: bold;">km_damp_max</span>
3911	has 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
3952	for 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
3969	This filter very efficiently
3970	eliminates 2-delta-waves sometimes cauesed by the upstream-spline
3971	scheme (see Mahrer and
3972	Pielke, 1978: Mon. Wea. Rev., 106, 818-830). It works in all three
3973	directions in space. A value of <b>long_filter_factor</b>
3974	= <i>0.01</i>
3975	sufficiently removes the small-scale waves without affecting the
3976	longer waves.<br>
3977
3978
3979
3980	</p>
3981
3982
3983
3984
3985
3986
3987
3988	<p>By default, the filter is
3989	switched off (= <i>0.0</i>).
3990	It is exclusively applied to the tendencies calculated by the
3991	upstream-spline scheme (see <a href="#momentum_advec">momentum_advec</a>
3992	and <a href="#scalar_advec">scalar_advec</a>),
3993	not to the prognostic variables themselves. At the bottom and top
3994	boundary of the model domain the filter effect for vertical
3995	2-delta-waves is reduced. There, the amplitude of these waves is only
3996	reduced by approx. 50%, otherwise by nearly 100%.  <br>
3997
3998
3999
4000
4001	Filter factors with values > <i>0.01</i> also
4002	reduce the amplitudes
4003	of waves with wavelengths longer than 2-delta (see the paper by Mahrer
4004	and
4005	Pielke, 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
4041	By
4042	default, the optimization method depends on the host on which PALM is
4043	running. On machines with vector-type CPUs, single 3d-loops are used to
4044	calculate each tendency term of each prognostic equation, while on all
4045	other machines, all prognostic equations are solved within one big loop
4046	over 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
4054	The 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
4099	1d-model.<br>
4100
4101
4102
4103	<br>
4104
4105
4106
4107
4108	By default the mixing length is calculated as in the 3d-model (i.e. it
4109	depends on the grid spacing).<br>
4110
4111
4112
4113	<br>
4114
4115
4116
4117
4118	By setting <span style="font-weight: bold;">mixing_length_1d</span>
4119	= <span style="font-style: italic;">'blackadar'</span>,
4120	the so-called Blackadar mixing length is used (l = kappa * z / ( 1 +
4121	kappa * 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
4166	switch on the prognostic equation for specific
4167	humidity q.<br>
4168
4169
4170
4171	</p>
4172
4173
4174
4175
4176
4177
4178
4179	<p>The initial vertical
4180	profile 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>
4181	and <a href="chapter_4.1.html#q_vertical_gradient_level">q_vertical_gradient_level</a>.
4182	Boundary conditions can be set via <a href="chapter_4.1.html#q_surface_initial_change">q_surface_initial_change</a>
4183	and <a href="chapter_4.1.html#surface_waterflux">surface_waterflux</a>.<br>
4184
4185
4186
4187
4188	</p>
4189
4190
4191
4192
4193	If 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
4195	humidity 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
4236	scheme to be used for the momentum equations.<br>
4237
4238
4239
4240	<br>
4241
4242
4243
4244
4245	The user can choose between the following schemes:<br>
4246
4247
4248
4249
4250	<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
4272	Piascek and
4273	Williams (1970, J. Comp. Phys., 6,
4274	392-405) with central differences in the form C3 is used.<br>
4275
4276
4277
4278
4279	If 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>
4281	the
4282	advection scheme is - for the Euler-timestep - automatically switched
4283	to 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
4317	upstream-spline scheme is
4318	used
4319	(see Mahrer and Pielke,
4320	1978: Mon. Wea. Rev., 106, 818-830). In opposite to the
4321	Piascek-Williams scheme, this is characterized by much better numerical
4322	features (less numerical diffusion, better preservation of flow
4323	structures, e.g. vortices), but computationally it is much more
4324	expensive. In
4325	addition, 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>),
4327	i.e. the
4328	timestep accuracy is only of first order.
4329	For this reason the advection of scalar variables (see <a href="#scalar_advec">scalar_advec</a>)
4330	should then also be carried out with the upstream-spline scheme,
4331	because otherwise the scalar variables would
4332	be subject to large numerical diffusion due to the upstream
4333	scheme.  </div>
4334
4335
4336
4337
4338
4339
4340
4341	<p style="margin-left: 40px;">Since
4342	the cubic splines used tend
4343	to overshoot under
4344	certain circumstances, this effect must be adjusted by suitable
4345	filtering 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>).
4348	This is always neccessary for runs with stable stratification,
4349	even 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
4363	stratification the
4364	upstream-spline scheme also
4365	produces gravity waves with large amplitude, which must be
4366	suitably 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
4376	upstream-spline scheme is not implemented for humidity and passive
4377	scalars (see <a href="#humidity">humidity</a>
4378	and <a href="#passive_scalar">passive_scalar</a>)
4379	and requires the use of a 2d-domain-decomposition. The last conditions
4380	severely restricts code optimization on several machines leading to
4381	very long execution times! The scheme is also not allowed for
4382	non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
4383	and <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
4444	the NetCDF output.<br>
4445
4446
4447
4448	<br>
4449
4450
4451
4452
4453	By default, all NetCDF output data (see <a href="chapter_4.2.html#data_output_format">data_output_format</a>)
4454	have single precision  (4 byte) accuracy. Double precision (8
4455	byte) can be choosen alternatively.<br>
4456
4457
4458
4459
4460	Accuracy for the different output data (cross sections, 3d-volume data,
4461	spectra, etc.) can be set independently.<br>
4462
4463
4464
4465	<span style="font-style: italic;">'<out>_NF90_REAL4'</span>
4466	(single precision) or <span style="font-style: italic;">'<out>_NF90_REAL8'</span>
4467	(double precision) are the two principally allowed values for <span style="font-weight: bold;">netcdf_precision</span>,
4468	where the string <span style="font-style: italic;">'<out>'
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
4530	section<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
4556	section<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
4660	time 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
4771	If all cross section data and the particle data shall be output in
4772	double 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>
4773	has 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
4820	along x-direction of the virtual
4821	processor
4822	net.  </p>
4823
4824
4825
4826
4827
4828
4829
4830	<p>For parallel runs, the total
4831	number of processors to be used
4832	is given by
4833	the <span style="font-weight: bold;">mrun</span>
4834	option <a href="http://www.muk.uni-hannover.de/software/mrun_beschreibung.html#Opt-X">-X</a>.
4835	By default, depending on the type of the parallel computer, PALM
4836	generates a 1d processor
4837	net (domain decomposition along x, <span style="font-weight: bold;">npey</span>
4838	= <span style="font-style: italic;">1</span>) or a
4839	2d-net (this is
4840	favored on machines with fast communication network). In case of a
4841	2d-net, it is tried to make it more or less square-shaped. If, for
4842	example, 16 processors are assigned (-X 16), a 4 * 4 processor net is
4843	generated (<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>).
4846	This choice is optimal for square total domains (<a href="#nx">nx</a>
4847	= <a href="#ny">ny</a>),
4848	since then the number of ghost points at the lateral boundarys of
4849	the subdomains is minimal. If <span style="font-weight: bold;">nx</span>
4850	nd <span style="font-weight: bold;">ny</span>
4851	differ extremely, the
4852	processor net should be manually adjusted using adequate values for <span style="font-weight: bold;">npex</span> and <span style="font-weight: bold;">npey</span>.  </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
4861	correspond to the
4862	value assigned by the <span style="font-weight: bold;">mrun</span>-option
4863	<tt>-X</tt>.
4864	Otherwise the model run will abort with a corresponding error
4865	message.  <br>
4866
4867
4868
4869
4870	Additionally, the specification of <span style="font-weight: bold;">npex</span>
4871	and <span style="font-weight: bold;">npey</span>
4872	may of course
4873	override the default setting for the domain decomposition (1d or 2d)
4874	which 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
4922	along y-direction of the virtual
4923	processor
4924	net.  </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
4977	of iterations with the SOR algorithm.  </p>
4978
4979
4980
4981
4982
4983
4984
4985	<p>This
4986	parameter is only effective if the SOR algorithm was
4987	selected as the pressure solver scheme (<a href="chapter_4.2.html#psolver">psolver</a>
4988	= <span style="font-style: italic;">'sor'</span>)
4989	and specifies the
4990	number of initial iterations of the SOR
4991	scheme (at t = 0). The number of subsequent iterations at the following
4992	timesteps is determined
4993	with the parameter <a href="#nsor">nsor</a>.
4994	Usually <b>nsor</b> < <b>nsor_ini</b>,
4995	since in each case
4996	subsequent calls to <a href="chapter_4.2.html#psolver">psolver</a>
4997	use the solution of the previous call as initial value. Suitable
4998	test runs should determine whether sufficient convergence of the
4999	solution is obtained with the default value and if necessary the value
5000	of <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
5048	points in x-direction.  </p>
5049
5050
5051
5052
5053
5054
5055
5056	<p>A value for this
5057	parameter must be assigned. Since the lower
5058	array bound in PALM
5059	starts with i = 0, the actual number of grid points is equal to <b>nx+1</b>.
5060	In 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
5070	parallel 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
5073	be an integral multiple
5074	of the processor numbers (see <a href="#npex">npex</a>
5075	and <a href="#npey">npey</a>)
5076	along x- as well as along y-direction (due to data
5077	transposition restrictions).</p>
5078
5079
5080
5081
5082
5083
5084	<p>For <a href="chapter_3.8.html">coupled runs</a> this parameter must be 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>
5085	and <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
5133	points in y-direction.  </p>
5134
5135
5136
5137
5138
5139
5140
5141	<p>A value for this
5142	parameter must be assigned. Since the lower
5143	array bound in PALM starts with i = 0, the actual number of grid points
5144	is equal to <b>ny+1</b>. In case of cyclic boundary
5145	conditions along
5146	y, 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
5157	be an integral multiple
5158	of the processor numbers (see <a href="#npex">npex</a>
5159	and <a href="#npey">npey</a>)
5160	along y- as well as along x-direction (due to data
5161	transposition restrictions).</p>
5162
5163
5164
5165
5166
5167
5168	<p>For <a href="chapter_3.8.html">coupled runs</a> this parameter must be 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>
5169	and <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
5217	points in z-direction.  </p>
5218
5219
5220
5221
5222
5223
5224
5225	<p>A value for this
5226	parameter must be assigned. Since the lower
5227	array bound in PALM
5228	starts with k = 0 and since one additional grid point is added at the
5229	top boundary (k = <b>nz+1</b>), the actual number of grid
5230	points is <b>nz+2</b>.
5231	However, the prognostic equations are only solved up to <b>nz</b>
5232	(u,
5233	v)
5234	or up to <b>nz-1</b> (w, scalar quantities). The top
5235	boundary for u
5236	and v is at k = <b>nz+1</b> (u, v) while at k = <b>nz</b>
5237	for all
5238	other quantities.  </p>
5239
5240
5241
5242
5243
5244
5245
5246	<p>For parallel
5247	runs,  in case of <a href="#grid_matching">grid_matching</a>
5248	= <span style="font-style: italic;">'strict'</span>,
5249	<b>nz</b> must
5250	be an integral multiple of
5251	the number of processors in x-direction (due to data transposition
5252	restrictions).</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 ocean runs.<br>
5281
5282
5283
5284	<br>
5285
5286
5287
5288	By default PALM is configured to simulate atmospheric flows. However, starting from version 3.3, <span style="font-weight: bold;">ocean</span> = <span style="font-style: italic;">.T.</span> allows 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
5312	density is calculated from the equation of state for seawater after
5313	each timestep, using the algorithm proposed by Jackett et al. (2006, J.
5314	Atmos. Oceanic Technol., <span style="font-weight: bold;">23</span>, 1709-1728).<br>
5315
5316
5317
5318	So 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 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
5349	Relevant 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
5357	Section <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
5406	velocity of the rotating system (in rad s<sup>-1</sup>).
5407	</p>
5408
5409
5410
5411
5412
5413
5414
5415	<p>The angular velocity of the earth is set by
5416	default. The
5417	values
5418	of the Coriolis parameters are calculated as:  </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>)
5435	<br>
5436
5437
5438
5439	f* = 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,
5482	nx/2</span> or <span style="font-style: italic;">ny/2)</span></td>
5483
5484
5485
5486
5487	<td style="vertical-align: top;">Width of
5488	the damping range in the vicinity of the outflow (gridpoints).<br>
5489
5490
5491
5492
5493	<br>
5494
5495
5496
5497
5498	When using non-cyclic lateral boundaries (see <a href="chapter_4.1.html#bc_lr">bc_lr</a>
5499	or <a href="chapter_4.1.html#bc_ns">bc_ns</a>),
5500	a smoothing has to be applied to the
5501	velocity field in the vicinity of the outflow in order to suppress any
5502	reflections of outgoing disturbances. This parameter controlls the
5503	horizontal range to which the smoothing is applied. The range is given
5504	in gridpoints counted from the respective outflow boundary. For further
5505	details about the smoothing see parameter <a href="chapter_4.1.html#km_damp_max">km_damp_max</a>,
5506	which 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
5547	for the overshooting of subgrid-scale TKE in
5548	case that the upstream-spline scheme is switched on (in m<sup>2</sup>/s<sup>2</sup>).
5549	</p>
5550
5551
5552
5553
5554
5555
5556
5557	<p>By deafult, if cut-off of overshoots is switched
5558	on for the
5559	upstream-spline scheme (see <a href="#cut_spline_overshoot">cut_spline_overshoot</a>),
5560	no overshoots are permitted at all. If <b>overshoot_limit_e</b>
5561	is given a non-zero value, overshoots with the respective
5562	amplitude (both upward and downward) are allowed.  </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
5615	for the overshooting of potential temperature in
5616	case that the upstream-spline scheme is switched on (in K).  </p>
5617
5618
5619
5620
5621
5622
5623
5624	<p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.
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
5674	overshooting of
5675	the u-component of velocity in case that the upstream-spline scheme is
5676	switched on (in m/s).
5677
5678
5679
5680	<p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.
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
5734	for the overshooting of the v-component of
5735	velocity in case that the upstream-spline scheme is switched on
5736	(in m/s).  </p>
5737
5738
5739
5740
5741
5742
5743
5744	<p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.
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
5798	for the overshooting of the w-component of
5799	velocity in case that the upstream-spline scheme is switched on
5800	(in m/s).  </p>
5801
5802
5803
5804
5805
5806
5807
5808	<p>For further information see <a href="#overshoot_limit_e">overshoot_limit_e</a>.
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
5862	switch on the prognostic equation for a passive
5863	scalar. <br>
5864
5865
5866
5867	</p>
5868
5869
5870
5871
5872
5873
5874
5875	<p>The initial vertical profile
5876	of s can be set via parameters <a href="#s_surface">s_surface</a>,
5877	<a href="#s_vertical_gradient">s_vertical_gradient</a>
5878	and  <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
5879	Boundary conditions can be set via <a href="#s_surface_initial_change">s_surface_initial_change</a>
5880	and <a href="#surface_scalarflux">surface_scalarflux</a>.
5881	</p>
5882
5883
5884
5885
5886
5887
5888
5889	<p><b>Note:</b> <br>
5890
5891
5892
5893
5894	With <span style="font-weight: bold;">passive_scalar</span>
5895	switched
5896	on, the simultaneous use of humidity (see <a href="#humidity">humidity</a>)
5897	is 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
5941	latitude (in degrees).  </p>
5942
5943
5944
5945
5946
5947
5948
5949	<p>The value of
5950	this parameter determines the value of the
5951	Coriolis parameters f and f*, provided that the angular velocity (see <a href="#omega">omega</a>)
5952	is 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
5996	switch on a Prandtl layer.  </p>
5997
5998
5999
6000
6001
6002
6003
6004	<p>By default,
6005	a Prandtl layer is switched on at the bottom
6006	boundary 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
6008	scalar quantities).
6009	In this case, at the bottom boundary, free-slip conditions for u and v
6010	(see <a href="#bc_uv_b">bc_uv_b</a>)
6011	are not allowed. Likewise, laminar
6012	simulations with constant eddy diffusivities (<a href="#km_constant">km_constant</a>)
6013	are forbidden.  </p>
6014
6015
6016
6017
6018
6019
6020
6021	<p>With Prandtl-layer
6022	switched 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
6024	automatically
6025	changed to <i>'neumann'</i> if necessary.  Also,
6026	the pressure
6027	boundary condition <a href="#bc_p_b">bc_p_b</a>
6028	= <i>'neumann+inhomo'</i>  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
6080	on the precipitation scheme.<br>
6081
6082
6083
6084	</p>
6085
6086
6087
6088
6089
6090
6091
6092	<p>For
6093	precipitation processes PALM uses a simplified Kessler
6094	scheme. This scheme only considers the
6095	so-called autoconversion, that means the generation of rain water by
6096	coagulation of cloud drops among themselves. Precipitation begins and
6097	is immediately removed from the flow as soon as the liquid water
6098	content 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
6131	refrence</span></td>
6132
6133
6134
6135	<td style="vertical-align: top;">Reference
6136	temperature to be used in all buoyancy terms (in K).<br>
6137
6138
6139
6140	<br>
6141
6142
6143
6144	By
6145	default, the instantaneous horizontal average over the total model
6146	domain is used.<br>
6147
6148
6149
6150	<br>
6151
6152
6153
6154	<span style="font-weight: bold;">Attention:</span><br>
6155
6156
6157
6158	In 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
6198	potential temperature (in K).  </p>
6199
6200
6201
6202
6203
6204
6205
6206	<p>This
6207	parameter 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,
6209	the
6210	initial vertical temperature profile is constructed with <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
6211	and <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level
6212	</a>.
6213	This 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
6224	In case of ocean runs (see <a href="#ocean">ocean</a>),
6225	this parameter gives the temperature value at the sea surface, which is
6226	at k=nzt. The profile is then constructed from the surface down to the
6227	bottom 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
6279	surface temperature to be made at the beginning of
6280	the 3d run
6281	(in K).  </p>
6282
6283
6284
6285
6286
6287
6288
6289	<p>If <b>pt_surface_initial_change</b>
6290	is set to a non-zero
6291	value, the near surface sensible heat flux is not allowed to be given
6292	simultaneously (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
6337	gradient(s) of the initial temperature profile (in
6338	K
6339	/ 100 m).  </p>
6340
6341
6342
6343
6344
6345
6346
6347	<p>This temperature gradient
6348	holds starting from the height
6349	level defined by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>
6350	(precisely: for all uv levels k where zu(k) >
6351	pt_vertical_gradient_level,
6352	pt_init(k) is set: pt_init(k) = pt_init(k-1) + dzu(k) * <b>pt_vertical_gradient</b>)
6353	up to the top boundary or up to the next height level defined
6354	by <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>.
6355	A total of 10 different gradients for 11 height intervals (10 intervals
6356	if <a href="#pt_vertical_gradient_level">pt_vertical_gradient_level</a>(1)
6357	= <i>0.0</i>) can be assigned. The surface temperature is
6358	assigned via <a href="#pt_surface">pt_surface</a>.
6359	</p>
6360
6361
6362
6363
6364
6365
6366
6367	<p>Example:  </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>,  <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
6407	defines the temperature profile to be neutrally
6408	stratified
6409	up to z = 500.0 m with a temperature given by <a href="#pt_surface">pt_surface</a>.
6410	For 500.0 m < z <= 1000.0 m the temperature gradient is
6411	1.0 K /
6412	100 m and for z > 1000.0 m up to the top boundary it is
6413	0.5 K / 100 m (it is assumed that the assigned height levels correspond
6414	with uv levels).</p>
6415
6416
6417
6418
6419
6420
6421	<p><span style="font-weight: bold;">Attention:</span><br>
6422
6423
6424
6425	In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>),
6426	the profile is constructed like described above, but starting from the
6427	sea surface (k=nzt) down to the bottom boundary of the model. Height
6428	levels 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>
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>
6489	is effective (in m).  </p>
6490
6491
6492
6493
6494
6495
6496
6497	<p>The height levels have to be assigned in ascending order. The
6498	default values result in a neutral stratification regardless of the
6499	values of <a href="#pt_vertical_gradient">pt_vertical_gradient</a>
6500	(unless the top boundary of the model is higher than 100000.0 m).
6501	For 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
6509	In case of ocean runs (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
6550	specific humidity / total water content (kg/kg).  </p>
6551
6552
6553
6554
6555
6556
6557
6558	<p>This
6559	parameter assigns the value of the specific humidity q at
6560	the surface (k=0).  Starting from this value, the initial
6561	humidity
6562	profile is constructed with  <a href="#q_vertical_gradient">q_vertical_gradient</a>
6563	and <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
6564	This 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
6616	surface specific humidity / total water content to
6617	be made at the beginning
6618	of the 3d run (kg/kg).  </p>
6619
6620
6621
6622
6623
6624
6625
6626	<p>If <b>q_surface_initial_change</b><i>
6627	</i>is set to a
6628	non-zero value the
6629	near surface latent heat flux (water flux) is not allowed to be given
6630	simultaneously (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
6675	gradient(s) of the initial humidity profile
6676	(in 1/100 m).  </p>
6677
6678
6679
6680
6681
6682
6683
6684	<p>This humidity gradient
6685	holds starting from the height
6686	level  defined by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>
6687	(precisely: for all uv levels k, where zu(k) >
6688	q_vertical_gradient_level,
6689	q_init(k) is set: q_init(k) = q_init(k-1) + dzu(k) * <b>q_vertical_gradient</b>)
6690	up to the top boundary or up to the next height level defined
6691	by <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>.
6692	A total of 10 different gradients for 11 height intervals (10 intervals
6693	if <a href="#q_vertical_gradient_level">q_vertical_gradient_level</a>(1)
6694	= <i>0.0</i>) can be asigned. The surface humidity is
6695	assigned
6696	via <a href="#q_surface">q_surface</a>. </p>
6697
6698
6699
6700
6701
6702
6703
6704	<p>Example:  </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>,  <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
6740	That defines the humidity to be constant with height up to z =
6741	500.0
6742	m with a
6743	value given by <a href="#q_surface">q_surface</a>.
6744	For 500.0 m < z <= 1000.0 m the humidity gradient is
6745	0.001 / 100
6746	m and for z > 1000.0 m up to the top boundary it is
6747	0.0005 / 100 m (it is assumed that the assigned height levels
6748	correspond with uv
6749	levels). </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>
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
6800	which on the humidity gradient defined by <a href="#q_vertical_gradient">q_vertical_gradient</a>
6801	is effective (in m).  </p>
6802
6803
6804
6805
6806
6807
6808
6809	<p>The height levels
6810	are to be assigned in ascending order. The
6811	default values result in a humidity constant with height regardless of
6812	the 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
6814	the 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
6859	switch on longwave radiation cooling at
6860	cloud-tops.  </p>
6861
6862
6863
6864
6865
6866
6867
6868	<p>Long-wave radiation
6869	processes are parameterized by the
6870	effective emissivity, which considers only the absorption and emission
6871	of long-wave radiation at cloud droplets. The radiation scheme can be
6872	used 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
6929	generator to be used for creating uniformly
6930	distributed random numbers. <br>
6931
6932
6933
6934	</p>
6935
6936
6937
6938
6939
6940
6941
6942	<p>It is
6943	used if random perturbations are to be imposed on the
6944	velocity field or on the surface heat flux field (see <a href="chapter_4.2.html#create_disturbances">create_disturbances</a>
6945	and <a href="chapter_4.2.html#random_heatflux">random_heatflux</a>).
6946	By default, the "Numerical Recipes" random number generator is used.
6947	This one provides exactly the same order of random numbers on all
6948	different machines and should be used in particular for comparison runs.<br>
6949
6950
6951
6952
6953	<br>
6954
6955
6956
6957
6958	Besides, a system-specific generator is available ( <b>random_generator</b>
6959	= <i>'system-specific')</i> which should particularly be
6960	used for runs
6961	on vector parallel computers (NEC), because the default generator
6962	cannot be vectorized and therefore significantly drops down the code
6963	performance 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
6976	Results from two otherwise identical model runs will not be comparable
6977	one-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
7018	impose random perturbations on the internal two-dimensional near
7019	surface heat flux field <span style="font-style: italic;">shf</span>.
7020	<br>
7021
7022
7023
7024	</p>
7025
7026
7027
7028	If a near surface heat flux is used as bottom
7029	boundary
7030	condition (see <a href="#surface_heatflux">surface_heatflux</a>),
7031	it is by default assumed to be horizontally homogeneous. Random
7032	perturbations can be imposed on the internal
7033	two-dimensional 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
7035	by
7036	multiplying the
7037	values at each mesh point with a normally distributed random number
7038	with a mean value and standard deviation of 1. This is repeated after
7039	every timestep.<br>
7040
7041
7042
7043	<br>
7044
7045
7046
7047
7048	In case of a non-flat <a href="#topography">topography</a>, assigning
7049	<b>random_heatflux</b>
7050	= <i>.T.</i> imposes random perturbations on the
7051	combined heat
7052	flux field <span style="font-style: italic;">shf</span>
7053	composed of <a href="#surface_heatflux">surface_heatflux</a>
7054	at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
7055	at 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
7095	the flux-Richardson number.  </p>
7096
7097
7098
7099
7100
7101
7102
7103	<p>With the
7104	Prandtl layer switched on (see <a href="#prandtl_layer">prandtl_layer</a>),
7105	flux-Richardson numbers (rif) are calculated for z=z<sub>p</sub>
7106	(k=1)
7107	in the 3d-model (in the 1d model for all heights). Their values in
7108	particular determine the
7109	values of the friction velocity (1d- and 3d-model) and the values of
7110	the eddy diffusivity (1d-model). With small wind velocities at the
7111	Prandtl layer top or small vertical wind shears in the 1d-model, rif
7112	can take up unrealistic large values. They are limited by an upper (<span style="font-weight: bold;">rif_max</span>) and lower
7113	limit (see <a href="#rif_min">rif_min</a>)
7114	for the flux-Richardson number. The condition <b>rif_max</b>
7115	> <b>rif_min</b>
7116	must 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
7160	the flux-Richardson number.  </p>
7161
7162
7163
7164
7165
7166
7167
7168	<p>For further
7169	explanations see <a href="#rif_max">rif_max</a>.
7170	The condition <b>rif_max</b> > <b>rif_min </b>must
7171	be 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
7215	length (in m).  </p>
7216
7217
7218
7219
7220
7221
7222
7223	<p>This parameter is
7224	effective only in case that a Prandtl layer
7225	is switched
7226	on (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). </p>
7260
7261
7262
7263	This 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
7268	parameter 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,
7269	the
7270	initial vertical salinity profile is constructed from the surface down to the bottom of the model (k=0) by using <a href="chapter_4.1.html#sa_vertical_gradient">sa_vertical_gradient</a>
7271	and <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).  </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
7321	holds starting from the height
7322	level 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) <
7324	sa_vertical_gradient_level, sa_init(k) is set: sa_init(k) =
7325	sa_init(k+1) - dzu(k+1) * <b>sa_vertical_gradient</b>) down to the bottom boundary or down to the next height level defined
7326	by <a href="chapter_4.1.html#sa_vertical_gradient_level">sa_vertical_gradient_level</a>.
7327	A total of 10 different gradients for 11 height intervals (10 intervals
7328	if <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
7330	assigned via <a href="chapter_4.1.html#sa_surface">sa_surface</a>.
7331	</p>
7332
7333
7334
7335
7336
7337
7338
7339	<p>Example:  </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>,  <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
7377	defines 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>.
7378	For -500.0 m < z <= -1000.0 m the salinity gradient is
7379	1.0 psu /
7380	100 m and for z < -1000.0 m down to the bottom boundary it is
7381	0.5 psu / 100 m (it is assumed that the assigned height levels correspond
7382	with 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>
7415	is effective (in m).  </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
7431	default values result in a constant salinity profile regardless of the
7432	values 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).
7434	For 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
7478	scheme to be used for the scalar quantities.  </p>
7479
7480
7481
7482
7483
7484
7485
7486	<p>The
7487	user 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
7513	Piascek and
7514	Williams (1970, J. Comp. Phys., 6,
7515	392-405) with central differences in the form C3 is used.<br>
7516
7517
7518
7519
7520	If 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>
7522	the
7523	advection scheme is - for the Euler-timestep - automatically switched
7524	to 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
7554	scheme modified by
7555	Chlond (1994, Mon.
7556	Wea. Rev., 122, 111-125). This is a conservative monotonous scheme with
7557	very small numerical diffusion and therefore very good conservation of
7558	scalar flow features. The scheme however, is computationally very
7559	expensive both because it is expensive itself and because it does (so
7560	far) not allow specific code optimizations (e.g. cache optimization).
7561	Choice of this
7562	scheme forces the Euler timestep scheme to be used for the scalar
7563	quantities. For output of horizontally averaged
7564	profiles of the resolved / total heat flux, <a href="chapter_4.2.html#data_output_pr">data_output_pr</a>
7565	= <i>'wptBC'</i> / <i>'wptBC' </i>should
7566	be used, instead of the
7567	standard profiles (<span style="font-style: italic;">'wpt'</span>
7568	and <span style="font-style: italic;">'wpt'</span>)
7569	because these are
7570	too inaccurate with this scheme. However, for subdomain analysis (see <a href="#statistic_regions">statistic_regions</a>)
7571	exactly the reverse holds: here <i>'wptBC'</i> and <i>'wptBC'</i>
7572	show very large errors and should not be used.<br>
7573
7574
7575
7576	<br>
7577
7578
7579
7580
7581	This scheme is not allowed for non-cyclic lateral boundary conditions
7582	(see <a href="#bc_lr">bc_lr</a>
7583	and <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
7605	is used
7606	(see Mahrer and Pielke,
7607	1978: Mon. Wea. Rev., 106, 818-830). In opposite to the Piascek
7608	Williams scheme, this is characterized by much better numerical
7609	features (less numerical diffusion, better preservation of flux
7610	structures, e.g. vortices), but computationally it is much more
7611	expensive. In
7612	addition, 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>),
7614	i.e. the
7615	timestep accuracy is only first order. For this reason the advection of
7616	momentum (see <a href="#momentum_advec">momentum_advec</a>)
7617	should then also be carried out with the upstream-spline scheme,
7618	because otherwise the momentum would
7619	be subject to large numerical diffusion due to the upstream
7620	scheme.  </p>
7621
7622
7623
7624
7625
7626
7627
7628	<p style="margin-left: 40px;">Since
7629	the cubic splines used tend
7630	to overshoot under
7631	certain circumstances, this effect must be adjusted by suitable
7632	filtering 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>).
7635	This is always neccesssary for runs with stable stratification,
7636	even if this stratification appears only in parts of the model
7637	domain.  </p>
7638
7639
7640
7641
7642
7643
7644
7645	<p style="margin-left: 40px;">With
7646	stable stratification the
7647	upstream-upline scheme also produces gravity waves with large
7648	amplitude, which must be
7649	suitably 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
7663	upstream-spline scheme is not implemented for humidity and passive
7664	scalars (see <a href="#humidity">humidity</a>
7665	and <a href="#passive_scalar">passive_scalar</a>)
7666	and requires the use of a 2d-domain-decomposition. The last conditions
7667	severely restricts code optimization on several machines leading to
7668	very long execution times! This scheme is also not allowed for
7669	non-cyclic lateral boundary conditions (see <a href="#bc_lr">bc_lr</a>
7670	and <a href="#bc_ns">bc_ns</a>).</p>
7671
7672
7673
7674	<br>
7675
7676
7677
7678	A
7679	differing advection scheme can be choosed for the subgrid-scale TKE
7680	using 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
7721	additional user-defined subdomains for which
7722	statistical analysis
7723	and corresponding output (profiles, time series) shall be
7724	made.  </p>
7725
7726
7727
7728
7729
7730
7731
7732	<p>By default, vertical profiles and
7733	other statistical quantities
7734	are calculated as horizontal and/or volume average of the total model
7735	domain. Beyond that, these calculations can also be carried out for
7736	subdomains which can be defined using the field <a href="chapter_3.5.3.html">rmask </a>within the
7737	user-defined software
7738	(see <a href="chapter_3.5.3.html">chapter
7739	3.5.3</a>). The number of these subdomains is determined with the
7740	parameter <b>statistic_regions</b>. Maximum 9 additional
7741	subdomains
7742	are allowed. The parameter <a href="chapter_4.3.html#region">region</a>
7743	can be used to assigned names (identifier) to these subdomains which
7744	are then used in the headers
7745	of the output files and plots.</p>
7746
7747
7748
7749
7750
7751
7752	<p>If the default NetCDF
7753	output format is selected (see parameter <a href="chapter_4.2.html#data_output_format">data_output_format</a>),
7754	data for the total domain and all defined subdomains are output to the
7755	same 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>).
7757	In case of <span style="font-weight: bold;">statistic_regions</span>
7758	> <span style="font-style: italic;">0</span>,
7759	data on the file for the different domains can be distinguished by a
7760	suffix which is appended to the quantity names. Suffix 0 means data for
7761	the total domain, suffix 1 means data for subdomain 1, etc.</p>
7762
7763
7764
7765
7766
7767
7768	<p>In
7769	case of <span style="font-weight: bold;">data_output_format</span>
7770	= <span style="font-style: italic;">'profil'</span>,
7771	individual local files for profiles (<a href="chapter_3.4.html#PLOT1D_DATA">PLOT1D_DATA</a>) are
7772	created for each subdomain. The individual subdomain files differ by
7773	their name (the
7774	number of the respective subdomain is attached, e.g.
7775	PLOT1D_DATA_1). In this case the name of the file with the data of
7776	the total domain is PLOT1D_DATA_0. If no subdomains
7777	are declared (<b>statistic_regions</b> = <i>0</i>),
7778	the name
7779	PLOT1D_DATA is used (this must be considered in the
7780	respective file connection statements of the <span style="font-weight: bold;">mrun</span> configuration
7781	file).</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
7820	heatflux<br>
7821
7822
7823
7824	</span></td>
7825
7826
7827
7828	<td style="vertical-align: top;">
7829
7830
7831
7832	<p>Kinematic sensible
7833	heat flux at the bottom surface (in K m/s).  </p>
7834
7835
7836
7837
7838
7839
7840
7841	<p>If
7842	a value is assigned to this parameter, the internal two-dimensional
7843	surface heat flux field <span style="font-style: italic;">shf</span>
7844	is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span> as
7845	bottom (horizontally homogeneous) boundary condition for the
7846	temperature equation. This additionally requires that a Neumann
7847	condition must be used for the potential temperature (see <a href="#bc_pt_b">bc_pt_b</a>),
7848	because otherwise the resolved scale may contribute to
7849	the surface flux so that a constant value cannot be guaranteed. Also,
7850	changes of the
7851	surface temperature (see <a href="#pt_surface_initial_change">pt_surface_initial_change</a>)
7852	are not allowed. The parameter <a href="#random_heatflux">random_heatflux</a>
7853	can be used to impose random perturbations on the (homogeneous) surface
7854	heat
7855	flux field <span style="font-style: italic;">shf</span>. </p>
7856
7857
7858
7859
7860
7861
7862
7863	<p>
7864	In case of a non-flat <a href="#topography">topography</a>, the
7865	internal two-dimensional surface heat
7866	flux field <span style="font-style: italic;">shf</span>
7867	is initialized with the value of <span style="font-weight: bold;">surface_heatflux</span>
7868	at the bottom surface and <a href="#wall_heatflux">wall_heatflux(0)</a>
7869	at the topography top face. The parameter<a href="#random_heatflux"> random_heatflux</a>
7870	can be used to impose random perturbations on this combined surface
7871	heat
7872	flux field <span style="font-style: italic;">shf</span>.
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
7882	at each timestep by u<sub></sub> theta<sub>*</sub>
7883	(of course only with <a href="#prandtl_layer">prandtl_layer</a>
7884	switched on). Here, u<sub>*</sub>
7885	and theta<sub>*</sub> are calculated from the Prandtl law
7886	assuming
7887	logarithmic wind and temperature
7888	profiles between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_pt_b">bc_pt_b</a>)
7889	must be used as bottom boundary condition for the potential temperature.</p>
7890
7891
7892
7893
7894
7895
7896	<p>See
7897	also <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
7942	pressure at the surface (in hPa).  </p>
7943
7944
7945
7946
7947	Starting from this surface value, the vertical pressure
7948	profile is calculated once at the beginning of the run assuming a
7949	neutrally stratified
7950	atmosphere. This is needed for
7951	converting between the liquid water potential temperature and the
7952	potential 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
7993	the surface (in kg/(m<sup>2</sup> s)).  </p>
7994
7995
7996
7997
7998
7999
8000
8001	<p>If a non-zero value is assigned to this parameter, the
8002	respective scalar flux value is used
8003	as bottom (horizontally homogeneous) boundary condition for the scalar
8004	concentration equation. This additionally requires that a
8005	Neumann
8006	condition must be used for the scalar concentration (see <a href="#bc_s_b">bc_s_b</a>),
8007	because otherwise the resolved scale may contribute to
8008	the surface flux so that a constant value cannot be guaranteed. Also,
8009	changes of the
8010	surface scalar concentration (see <a href="#s_surface_initial_change">s_surface_initial_change</a>)
8011	are not allowed. <br>
8012
8013
8014
8015	</p>
8016
8017
8018
8019
8020
8021
8022
8023	<p>If no surface scalar
8024	flux is assigned (<b>surface_scalarflux</b>
8025	= <i>0.0</i>),
8026	it is calculated at each timestep by u<sub></sub> s<sub>*</sub>
8027	(of course only with Prandtl layer switched on). Here, s<sub>*</sub>
8028	is calculated from the Prandtl law assuming a logarithmic scalar
8029	concentration
8030	profile between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_s_b">bc_s_b</a>)
8031	must be used as bottom boundary condition for the scalar concentration.</p>
8032
8033
8034
8035
8036	</td>
8037
8038
8039
8040	</tr>
8041
8042
8043
8044	<tr>
8045
8046
8047
8048	<td style="vertical-align: top;">
8049
8050
8051
8052	<p><a name="surface_waterflux"></a><b>surface_waterflux</b></p>
8053
8054
8055
8056
8057	</td>
8058
8059
8060
8061	<td style="vertical-align: top;">R</td>
8062
8063
8064
8065
8066	<td style="vertical-align: top;"><i>0.0</i></td>
8067
8068
8069
8070
8071	<td style="vertical-align: top;">
8072
8073
8074
8075	<p>Kinematic
8076	water flux near the surface (in m/s).  </p>
8077
8078
8079
8080
8081
8082
8083
8084	<p>If
8085	a non-zero value is assigned to this parameter, the
8086	respective water flux value is used
8087	as bottom (horizontally homogeneous) boundary condition for the
8088	humidity equation. This additionally requires that a Neumann
8089	condition must be used for the specific humidity / total water content
8090	(see <a href="#bc_q_b">bc_q_b</a>),
8091	because otherwise the resolved scale may contribute to
8092	the surface flux so that a constant value cannot be guaranteed. Also,
8093	changes of the
8094	surface humidity (see <a href="#q_surface_initial_change">q_surface_initial_change</a>)
8095	are not allowed.<br>
8096
8097
8098
8099	</p>
8100
8101
8102
8103
8104
8105
8106
8107	<p>If no surface water
8108	flux is assigned (<b>surface_waterflux</b>
8109	= <i>0.0</i>),
8110	it is calculated at each timestep by u<sub></sub> q<sub>*</sub>
8111	(of course only with Prandtl layer switched on). Here, q<sub>*</sub>
8112	is calculated from the Prandtl law assuming a logarithmic temperature
8113	profile between k=0 and k=1. In this case a Dirichlet condition (see <a href="#bc_q_b">bc_q_b</a>)
8114	must be used as the bottom boundary condition for the humidity.</p>
8115
8116
8117
8118
8119	</td>
8120
8121
8122
8123	</tr>
8124
8125
8126
8127	<tr>
8128
8129
8130
8131	<td style="vertical-align: top;">
8132
8133
8134
8135	<p><a name="s_surface"></a><b>s_surface</b></p>
8136
8137
8138
8139
8140	</td>
8141
8142
8143
8144	<td style="vertical-align: top;">R</td>
8145
8146
8147
8148
8149	<td style="vertical-align: top;"><i>0.0</i></td>
8150
8151
8152
8153
8154	<td style="vertical-align: top;">
8155
8156
8157
8158	<p>Surface value
8159	of the passive scalar (in kg/m<sup>3</sup>). <br>
8160
8161
8162
8163
8164	</p>
8165
8166
8167
8168
8169	This parameter assigns the value of the passive scalar s at
8170	the surface (k=0)<b>.</b> Starting from this value, the
8171	initial vertical scalar concentration profile is constructed with<a href="#s_vertical_gradient">
8172	s_vertical_gradient</a> and <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.</td>
8173
8174
8175
8176
8177	</tr>
8178
8179
8180
8181	<tr>
8182
8183
8184
8185	<td style="vertical-align: top;">
8186
8187
8188
8189	<p><a name="s_surface_initial_change"></a><b>s_surface_initial</b>
8190	<br>
8191
8192
8193
8194	<b>_change</b></p>
8195
8196
8197
8198	</td>
8199
8200
8201
8202	<td style="vertical-align: top;">R</td>
8203
8204
8205
8206	<td style="vertical-align: top;"><i>0.0</i></td>
8207
8208
8209
8210
8211	<td style="vertical-align: top;">
8212
8213
8214
8215	<p>Change in
8216	surface scalar concentration to be made at the
8217	beginning of the 3d run (in kg/m<sup>3</sup>).  </p>
8218
8219
8220
8221
8222
8223
8224
8225	<p>If <b>s_surface_initial_change</b><i> </i>is
8226	set to a
8227	non-zero
8228	value, the near surface scalar flux is not allowed to be given
8229	simultaneously (see <a href="#surface_scalarflux">surface_scalarflux</a>).</p>
8230
8231
8232
8233
8234	</td>
8235
8236
8237
8238	</tr>
8239
8240
8241
8242	<tr>
8243
8244
8245
8246	<td style="vertical-align: top;">
8247
8248
8249
8250	<p><a name="s_vertical_gradient"></a><b>s_vertical_gradient</b></p>
8251
8252
8253
8254
8255	</td>
8256
8257
8258
8259	<td style="vertical-align: top;">R (10)</td>
8260
8261
8262
8263
8264	<td style="vertical-align: top;"><i>10 * 0</i><i>.0</i></td>
8265
8266
8267
8268
8269	<td style="vertical-align: top;">
8270
8271
8272
8273	<p>Scalar
8274	concentration gradient(s) of the initial scalar
8275	concentration profile (in kg/m<sup>3 </sup>/
8276	100 m).  </p>
8277
8278
8279
8280
8281
8282
8283
8284	<p>The scalar gradient holds
8285	starting from the height level
8286	defined by <a href="#s_vertical_gradient_level">s_vertical_gradient_level
8287	</a>(precisely: for all uv levels k, where zu(k) >
8288	s_vertical_gradient_level, s_init(k) is set: s_init(k) = s_init(k-1) +
8289	dzu(k) * <b>s_vertical_gradient</b>) up to the top
8290	boundary or up to
8291	the next height level defined by <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>.
8292	A total of 10 different gradients for 11 height intervals (10 intervals
8293	if <a href="#s_vertical_gradient_level">s_vertical_gradient_level</a>(1)
8294	= <i>0.0</i>) can be assigned. The surface scalar value is
8295	assigned
8296	via <a href="#s_surface">s_surface</a>.<br>
8297
8298
8299
8300	</p>
8301
8302
8303
8304
8305
8306
8307
8308	<p>Example:  </p>
8309
8310
8311
8312
8313
8314
8315
8316	<ul>
8317
8318
8319
8320
8321
8322
8323
8324	<p><b>s_vertical_gradient</b>
8325	= <i>0.1</i>, <i>0.05</i>,  <br>
8326
8327
8328
8329
8330	<b>s_vertical_gradient_level</b> = <i>500.0</i>,
8331	<i>1000.0</i>,</p>
8332
8333
8334
8335
8336
8337
8338
8339	</ul>
8340
8341
8342
8343
8344
8345
8346
8347	<p>That
8348	defines the scalar concentration to be constant with
8349	height up to z = 500.0 m with a value given by <a href="#s_surface">s_surface</a>.
8350	For 500.0 m < z <= 1000.0 m the scalar gradient is 0.1
8351	kg/m<sup>3 </sup>/ 100 m and for z > 1000.0 m up to
8352	the top
8353	boundary it is 0.05 kg/m<sup>3 </sup>/ 100 m (it is
8354	assumed that the
8355	assigned height levels
8356	correspond with uv
8357	levels).</p>
8358
8359
8360
8361	</td>
8362
8363
8364
8365	</tr>
8366
8367
8368
8369	<tr>
8370
8371
8372
8373	<td style="vertical-align: top;">
8374
8375
8376
8377	<p><a name="s_vertical_gradient_level"></a><b>s_vertical_gradient_</b>
8378	<br>
8379
8380
8381
8382	<b>level</b></p>
8383
8384
8385
8386	</td>
8387
8388
8389
8390	<td style="vertical-align: top;">R (10)</td>
8391
8392
8393
8394	<td style="vertical-align: top;">
8395
8396
8397
8398	<p><i>10 *</i>
8399	<i>0.0</i></p>
8400
8401
8402
8403	</td>
8404
8405
8406
8407	<td style="vertical-align: top;">
8408
8409
8410
8411	<p>Height level from
8412	which on the scalar gradient defined by <a href="#s_vertical_gradient">s_vertical_gradient</a>
8413	is effective (in m).  </p>
8414
8415
8416
8417
8418
8419
8420
8421	<p>The height levels
8422	are to be assigned in ascending order. The
8423	default values result in a scalar concentration constant with height
8424	regardless of the values of <a href="#s_vertical_gradient">s_vertical_gradient</a>
8425	(unless the top boundary of the model is higher than 100000.0 m). For
8426	the
8427	piecewise construction of scalar concentration profiles see <a href="#s_vertical_gradient">s_vertical_gradient</a>.</p>
8428
8429
8430
8431
8432	</td>
8433
8434
8435
8436	</tr>
8437
8438
8439
8440	<tr>
8441
8442
8443
8444	<td style="vertical-align: top;">
8445
8446
8447
8448	<p><a name="timestep_scheme"></a><b>timestep_scheme</b></p>
8449
8450
8451
8452
8453	</td>
8454
8455
8456
8457	<td style="vertical-align: top;">C * 20</td>
8458
8459
8460
8461
8462	<td style="vertical-align: top;">
8463
8464
8465
8466	<p><i>'runge</i><br>
8467
8468
8469
8470
8471	<i>kutta-3'</i></p>
8472
8473
8474
8475	</td>
8476
8477
8478
8479	<td style="vertical-align: top;">
8480
8481
8482
8483	<p>Time step scheme to
8484	be used for the integration of the prognostic
8485	variables.  </p>
8486
8487
8488
8489
8490
8491
8492
8493	<p>The user can choose between
8494	the following schemes:<br>
8495
8496
8497
8498	</p>
8499
8500
8501
8502
8503
8504
8505
8506	<p><span style="font-style: italic;">'runge-kutta-3'</span><br>
8507
8508
8509
8510
8511	</p>
8512
8513
8514
8515
8516
8517
8518
8519	<div style="margin-left: 40px;">Third order
8520	Runge-Kutta scheme.<br>
8521
8522
8523
8524
8525	This scheme requires the use of <a href="#momentum_advec">momentum_advec</a>
8526	= <a href="#scalar_advec">scalar_advec</a>
8527	= '<i>pw-scheme'</i>. Please refer to the <a href="../tec/numerik.heiko/zeitschrittverfahren.pdf">documentation
8528	on PALM's time integration schemes (28p., in German)</a>
8529	fur further details.<br>
8530
8531
8532
8533	</div>
8534
8535
8536
8537
8538
8539
8540
8541	<p><span style="font-style: italic;">'runge-kutta-2'</span><br>
8542
8543
8544
8545
8546	</p>
8547
8548
8549
8550
8551
8552
8553
8554	<div style="margin-left: 40px;">Second order
8555	Runge-Kutta scheme.<br>
8556
8557
8558
8559
8560	For special features see <b>timestep_scheme</b> = '<i>runge-kutta-3'</i>.<br>
8561
8562
8563
8564
8565	</div>
8566
8567
8568
8569	<br>
8570
8571
8572
8573	<span style="font-style: italic;"><span style="font-style: italic;">'leapfrog'</span><br>
8574
8575
8576
8577
8578	<br>
8579
8580
8581
8582	</span>
8583
8584
8585
8586	<div style="margin-left: 40px;">Second
8587	order leapfrog scheme.<br>
8588
8589
8590
8591
8592	Although this scheme requires a constant timestep (because it is
8593	centered in time),  is even applied in case of changes in
8594	timestep. Therefore, only small
8595	changes of the timestep are allowed (see <a href="#dt">dt</a>).
8596	However, an Euler timestep is always used as the first timestep of an
8597	initiali run. When using the Bott-Chlond scheme for scalar advection
8598	(see <a href="#scalar_advec">scalar_advec</a>),
8599	the prognostic equation for potential temperature will be calculated
8600	with the Euler scheme, although the leapfrog scheme is switched
8601	on.  <br>
8602
8603
8604
8605
8606	The leapfrog scheme must not be used together with the upstream-spline
8607	scheme for calculating the advection (see <a href="#scalar_advec">scalar_advec</a>
8608	= '<i>ups-scheme'</i> and <a href="#momentum_advec">momentum_advec</a>
8609	= '<i>ups-scheme'</i>).<br>
8610
8611
8612
8613	</div>
8614
8615
8616
8617	<br>
8618
8619
8620
8621
8622	<span style="font-style: italic;">'</span><span style="font-style: italic;"><span style="font-style: italic;">leapfrog+euler'</span><br>
8623
8624
8625
8626
8627	<br>
8628
8629
8630
8631	</span>
8632
8633
8634
8635	<div style="margin-left: 40px;">The
8636	leapfrog scheme is used, but
8637	after each change of a timestep an Euler timestep is carried out.
8638	Although this method is theoretically correct (because the pure
8639	leapfrog method does not allow timestep changes), the divergence of the
8640	velocity field (after applying the pressure solver) may be
8641	significantly larger than with <span style="font-style: italic;">'leapfrog'</span>.<br>
8642
8643
8644
8645
8646	</div>
8647
8648
8649
8650	<br>
8651
8652
8653
8654	<span style="font-style: italic;">'euler'</span><br>
8655
8656
8657
8658
8659	<br>
8660
8661
8662
8663
8664
8665
8666
8667	<div style="margin-left: 40px;">First order
8668	Euler scheme.  <br>
8669
8670
8671
8672
8673	The Euler scheme must be used when treating the advection terms with
8674	the upstream-spline scheme (see <a href="#scalar_advec">scalar_advec</a>
8675	= <span style="font-style: italic;">'ups-scheme'</span>
8676	and <a href="#momentum_advec">momentum_advec</a>
8677	= <span style="font-style: italic;">'ups-scheme'</span>).</div>
8678
8679
8680
8681
8682	<br>
8683
8684
8685
8686	<br>
8687
8688
8689
8690	A differing timestep scheme can be choosed for the
8691	subgrid-scale TKE using parameter <a href="#use_upstream_for_tke">use_upstream_for_tke</a>.<br>
8692
8693
8694
8695
8696	</td>
8697
8698
8699
8700	</tr>
8701
8702
8703
8704	<tr>
8705
8706
8707
8708	<td style="text-align: left; vertical-align: top;"><span style="font-weight: bold;"><a name="topography"></a></span><span style="font-weight: bold;">topography</span></td>
8709
8710
8711
8712
8713	<td style="vertical-align: top;">C * 40</td>
8714
8715
8716
8717	<td style="vertical-align: top;"><span style="font-style: italic;">'flat'</span></td>
8718
8719
8720
8721	<td>
8722
8723
8724
8725	<p>Topography mode.  </p>
8726
8727
8728
8729
8730
8731
8732
8733	<p>The user can
8734	choose between the following modes:<br>
8735
8736
8737
8738	</p>
8739
8740
8741
8742
8743
8744
8745
8746	<p><span style="font-style: italic;">'flat'</span><br>
8747
8748
8749
8750	</p>
8751
8752
8753
8754
8755
8756
8757
8758	<div style="margin-left: 40px;">Flat surface.</div>
8759
8760
8761
8762
8763
8764
8765
8766	<p><span style="font-style: italic;">'single_building'</span><br>
8767
8768
8769
8770
8771	</p>
8772
8773
8774
8775
8776
8777
8778
8779	<div style="margin-left: 40px;">Flow
8780	around a single rectangular building mounted on a flat surface.<br>
8781
8782
8783
8784
8785	The building size and location can be specified with the parameters <a href="#building_height">building_height</a>, <a href="#building_length_x">building_length_x</a>, <a href="#building_length_y">building_length_y</a>, <a href="#building_wall_left">building_wall_left</a> and <a href="#building_wall_south">building_wall_south</a>.</div>
8786
8787
8788
8789
8790	<span style="font-style: italic;"></span>
8791
8792
8793
8794	<p><span style="font-style: italic;">'read_from_file'</span><br>
8795
8796
8797
8798
8799	</p>
8800
8801
8802
8803
8804
8805
8806
8807	<div style="margin-left: 40px;">Flow around
8808	arbitrary topography.<br>
8809
8810
8811
8812
8813	This mode requires the input file <a href="chapter_3.4.html#TOPOGRAPHY_DATA">TOPOGRAPHY_DATA</a><font color="#000000">. This file contains </font><font color="#000000"><font color="#000000">the </font></font><font color="#000000">arbitrary topography </font><font color="#000000"><font color="#000000">height
8814	information</font></font><font color="#000000">
8815	in m. These data <span style="font-style: italic;"></span>must
8816	exactly match the horizontal grid.</font> </div>
8817
8818
8819
8820	<span style="font-style: italic;"><br>
8821
8822
8823
8824	</span><font color="#000000">
8825	Alternatively, the user may add code to the user interface subroutine <a href="chapter_3.5.1.html#user_init_grid">user_init_grid</a>
8826	to allow further topography modes.<br>
8827
8828
8829
8830	<br>
8831
8832
8833
8834
8835	All non-flat <span style="font-weight: bold;">topography</span>
8836	modes </font>require the use of <a href="#momentum_advec">momentum_advec</a>
8837	= <a href="#scalar_advec">scalar_advec</a>
8838	= '<i>pw-scheme'</i>, <a href="chapter_4.2.html#psolver">psolver</a>
8839	= <i>'poisfft'</i> or '<i>poisfft_hybrid'</i>,
8840	<i> </i><a href="#alpha_surface">alpha_surface</a>
8841	= 0.0, <a href="#bc_lr">bc_lr</a> = <a href="#bc_ns">bc_ns</a> = <span style="font-style: italic;">'cyclic'</span>, <a style="" href="#galilei_transformation">galilei_transformation</a>
8842	= <span style="font-style: italic;">.F.</span>, <a href="#cloud_physics">cloud_physics </a> = <span style="font-style: italic;">.F.</span>,  <a href="#cloud_droplets">cloud_droplets</a> = <span style="font-style: italic;">.F.</span>,  <a href="#humidity">humidity</a> = <span style="font-style: italic;">.F.</span>, and <a href="#prandtl_layer">prandtl_layer</a> = .T..<br>
8843
8844
8845
8846
8847	<font color="#000000"><br>
8848
8849
8850
8851
8852	Note that an inclined model domain requires the use of <span style="font-weight: bold;">topography</span> = <span style="font-style: italic;">'flat'</span> and a
8853	nonzero </font><a href="#alpha_surface">alpha_surface</a>.</td>
8854
8855
8856
8857
8858	</tr>
8859
8860
8861
8862	<tr>
8863
8864
8865
8866	<td style="vertical-align: top;"><a name="top_heatflux"></a><span style="font-weight: bold;">top_heatflux</span></td>
8867
8868
8869
8870	<td style="vertical-align: top;">R</td>
8871
8872
8873
8874	<td style="vertical-align: top;"><span style="font-style: italic;">no prescribed<br>
8875
8876
8877
8878
8879	heatflux</span></td>
8880
8881
8882
8883	<td style="vertical-align: top;">
8884
8885
8886
8887	<p>Kinematic
8888	sensible heat flux at the top boundary (in K m/s).  </p>
8889
8890
8891
8892
8893
8894
8895
8896	<p>If a value is assigned to this parameter, the internal
8897	two-dimensional surface heat flux field <span style="font-family: monospace;">tswst</span> is
8898	initialized with the value of <span style="font-weight: bold;">top_heatflux</span> as
8899	top (horizontally homogeneous) boundary condition for the
8900	temperature equation. This additionally requires that a Neumann
8901	condition must be used for the potential temperature (see <a href="chapter_4.1.html#bc_pt_t">bc_pt_t</a>),
8902	because otherwise the resolved scale may contribute to
8903	the top flux so that a constant flux value cannot be guaranteed.<span style="font-style: italic;"></span> </p>
8904
8905
8906
8907
8908
8909
8910
8911	<p><span style="font-weight: bold;">Note:</span><br>
8912
8913
8914
8915	The
8916	application of a top heat flux additionally requires the setting of
8917	initial parameter <a href="#use_top_fluxes">use_top_fluxes</a>
8918	= .T..<span style="font-style: italic;"></span><span style="font-weight: bold;"></span> </p>
8919
8920
8921
8922
8923
8924
8925	<p>No
8926	Prandtl-layer is available at the top boundary so far.</p>
8927
8928
8929
8930
8931
8932
8933	<p>See
8934	also <a href="#surface_heatflux">surface_heatflux</a>.</p>
8935
8936
8937
8938
8939	</td>
8940
8941
8942
8943	</tr>
8944
8945
8946
8947	<tr>
8948
8949
8950
8951	<td style="vertical-align: top;"><a name="top_momentumflux_u"></a><span style="font-weight: bold;">top_momentumflux_u</span></td>
8952
8953
8954
8955	<td style="vertical-align: top;">R</td>
8956
8957
8958
8959	<td style="vertical-align: top;"><span style="font-style: italic;">no prescribed momentumflux</span></td>
8960
8961
8962
8963	<td style="vertical-align: top;">Momentum flux along x at the top boundary (in m2/s2).<br>
8964
8965
8966
8967
8968
8969
8970	<p>If a value is assigned to this parameter, the internal
8971	two-dimensional u-momentum flux field <span style="font-family: monospace;">uswst</span> is
8972	initialized with the value of <span style="font-weight: bold;">top_momentumflux_u</span> as
8973	top (horizontally homogeneous) boundary condition for the u-momentum equation.</p>
8974
8975
8976
8977
8978
8979
8980	<p><span style="font-weight: bold;">Notes:</span><br>
8981
8982
8983
8984	The
8985	application of a top momentum flux additionally requires the setting of
8986	initial parameter <a href="chapter_4.1.html#use_top_fluxes">use_top_fluxes</a>
8987	= .T.. Setting of <span style="font-weight: bold;">top_momentumflux_u</span> requires setting of <a href="#top_momentumflux_v">top_momentumflux_v</a> also.</p>
8988
8989
8990
8991
8992
8993
8994	<p>A Neumann
8995	condition should be used for the u velocity component (see <a href="chapter_4.1.html#bc_uv_t">bc_uv_t</a>),
8996	because otherwise the resolved scale may contribute to
8997	the top flux so that a constant flux value cannot be guaranteed.<span style="font-style: italic;"></span> </p>
8998
8999
9000
9001
9002	<span style="font-weight: bold;"></span>
9003
9004
9005
9006	<p>No
9007	Prandtl-layer is available at the top boundary so far.</p>
9008
9009
9010
9011
9012
9013
9014	<p> The <a href="chapter_3.8.html">coupled</a> ocean parameter file <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a> should include dummy REAL value assignments to both <a href="chapter_4.1.html#top_momentumflux_u">top_momentumflux_u</a> and <a href="chapter_4.1.html#top_momentumflux_v">top_momentumflux_v</a> (e.g. top_momentumflux_u = 0.0, top_momentumflux_v = 0.0) to enable the momentum flux coupling.</p>
9015
9016
9017
9018	</td>
9019
9020
9021
9022	</tr>
9023
9024
9025
9026	<tr>
9027
9028
9029
9030	<td style="vertical-align: top;"><a name="top_momentumflux_v"></a><span style="font-weight: bold;">top_momentumflux_v</span></td>
9031
9032
9033
9034	<td style="vertical-align: top;">R</td>
9035
9036
9037
9038	<td style="vertical-align: top;"><span style="font-style: italic;">no prescribed momentumflux</span></td>
9039
9040
9041
9042	<td style="vertical-align: top;">Momentum flux along y at the top boundary (in m2/s2).<br>
9043
9044
9045
9046
9047
9048
9049	<p>If a value is assigned to this parameter, the internal
9050	two-dimensional v-momentum flux field <span style="font-family: monospace;">vswst</span> is
9051	initialized with the value of <span style="font-weight: bold;">top_momentumflux_v</span> as
9052	top (horizontally homogeneous) boundary condition for the v-momentum equation.</p>
9053
9054
9055
9056
9057
9058
9059	<p><span style="font-weight: bold;">Notes:</span><br>
9060
9061
9062
9063	The
9064	application of a top momentum flux additionally requires the setting of
9065	initial parameter <a href="chapter_4.1.html#use_top_fluxes">use_top_fluxes</a>
9066	= .T.. Setting of <span style="font-weight: bold;">top_momentumflux_v</span> requires setting of <a href="chapter_4.1.html#top_momentumflux_u">top_momentumflux_u</a> also.</p>
9067
9068
9069
9070
9071
9072
9073	<p>A Neumann
9074	condition should be used for the v velocity component (see <a href="chapter_4.1.html#bc_uv_t">bc_uv_t</a>),
9075	because otherwise the resolved scale may contribute to
9076	the top flux so that a constant flux value cannot be guaranteed.<span style="font-style: italic;"></span> </p>
9077
9078
9079
9080
9081	<span style="font-weight: bold;"></span>
9082
9083
9084
9085	<p>No
9086	Prandtl-layer is available at the top boundary so far.</p>
9087
9088
9089
9090
9091
9092
9093	<p> The <a href="chapter_3.8.html">coupled</a> ocean parameter file <a href="chapter_3.4.html#PARIN"><font style="font-size: 10pt;" size="2">PARIN_O</font></a> should include dummy REAL value assignments to both <a href="chapter_4.1.html#top_momentumflux_u">top_momentumflux_u</a> and <a href="chapter_4.1.html#top_momentumflux_v">top_momentumflux_v</a> (e.g. top_momentumflux_u = 0.0, top_momentumflux_v = 0.0) to enable the momentum flux coupling.</p>
9094
9095
9096
9097	</td>
9098
9099
9100
9101	</tr>
9102
9103
9104
9105	<tr>
9106
9107
9108
9109	<td style="vertical-align: top;"><a name="top_salinityflux"></a><span style="font-weight: bold;">top_salinityflux</span></td>
9110
9111
9112
9113	<td style="vertical-align: top;">R</td>
9114
9115
9116
9117	<td style="vertical-align: top;"><span style="font-style: italic;">no prescribed<br>
9118
9119
9120
9121
9122	salinityflux</span></td>
9123
9124
9125
9126	<td style="vertical-align: top;">
9127
9128
9129
9130	<p>Kinematic
9131	salinity flux at the top boundary, i.e. the sea surface (in psu m/s).  </p>
9132
9133
9134
9135
9136
9137
9138
9139	<p>This parameter only comes into effect for ocean runs (see parameter <a href="chapter_4.1.html#ocean">ocean</a>).</p>
9140
9141
9142
9143
9144
9145
9146	<p>If a value is assigned to this parameter, the internal
9147	two-dimensional surface heat flux field <span style="font-family: monospace;">saswst</span> is
9148	initialized with the value of <span style="font-weight: bold;">top_salinityflux</span> as
9149	top (horizontally homogeneous) boundary condition for the salinity equation. This additionally requires that a Neumann
9150	condition must be used for the salinity (see <a href="chapter_4.1.html#bc_sa_t">bc_sa_t</a>),
9151	because otherwise the resolved scale may contribute to
9152	the top flux so that a constant flux value cannot be guaranteed.<span style="font-style: italic;"></span> </p>
9153
9154
9155
9156
9157
9158
9159
9160	<p><span style="font-weight: bold;">Note:</span><br>
9161
9162
9163
9164	The
9165	application of a salinity flux at the model top additionally requires the setting of
9166	initial parameter <a href="chapter_4.1.html#use_top_fluxes">use_top_fluxes</a>
9167	= .T..<span style="font-style: italic;"></span><span style="font-weight: bold;"></span> </p>
9168
9169
9170
9171
9172
9173
9174	<p>See
9175	also <a href="chapter_4.1.html#bottom_salinityflux">bottom_salinityflux</a>.</p>
9176
9177
9178
9179	</td>
9180
9181
9182
9183	</tr>
9184
9185
9186
9187	<tr>
9188
9189
9190
9191	<td style="vertical-align: top;">
9192
9193
9194
9195	<p><a name="ug_surface"></a><span style="font-weight: bold;">ug_surface</span></p>
9196
9197
9198
9199
9200	</td>
9201
9202
9203
9204	<td style="vertical-align: top;">R<br>
9205
9206
9207
9208	</td>
9209
9210
9211
9212
9213	<td style="vertical-align: top;"><span style="font-style: italic;">0.0</span><br>
9214
9215
9216
9217	</td>
9218
9219
9220
9221
9222	<td style="vertical-align: top;">u-component of the
9223	geostrophic
9224	wind at the surface (in m/s).<br>
9225
9226
9227
9228	<br>
9229
9230
9231
9232
9233	This parameter assigns the value of the u-component of the geostrophic
9234	wind (ug) at the surface (k=0). Starting from this value, the initial
9235	vertical profile of the <br>
9236
9237
9238
9239
9240	u-component of the geostrophic wind is constructed with <a href="#ug_vertical_gradient">ug_vertical_gradient</a>
9241	and <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>.
9242	The
9243	profile constructed in that way is used for creating the initial
9244	vertical velocity profile of the 3d-model. Either it is applied, as it
9245	has been specified by the user (<a href="#initializing_actions">initializing_actions</a>
9246	= 'set_constant_profiles') or it is used for calculating a stationary
9247	boundary layer wind profile (<a href="#initializing_actions">initializing_actions</a>
9248	= 'set_1d-model_profiles'). If ug is constant with height (i.e. ug(k)=<span style="font-weight: bold;">ug_surface</span>)
9249	and  has a large
9250	value, it is recommended to use a Galilei-transformation of the
9251	coordinate system, if possible (see <a href="#galilei_transformation">galilei_transformation</a>),
9252	in order to obtain larger time steps.<br>
9253
9254
9255
9256	<br>
9257
9258
9259
9260	<span style="font-weight: bold;">Attention:</span><br>
9261
9262
9263
9264	In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>),
9265	this parameter gives the velocity value at the sea surface, which is
9266	at k=nzt. The profile is then constructed from the surface down to the
9267	bottom of the model.<br>
9268
9269
9270
9271	</td>
9272
9273
9274
9275	</tr>
9276
9277
9278
9279
9280	<tr>
9281
9282
9283
9284	<td style="vertical-align: top;">
9285
9286
9287
9288	<p><a name="ug_vertical_gradient"></a><span style="font-weight: bold;">ug_vertical_gradient</span></p>
9289
9290
9291
9292
9293	</td>
9294
9295
9296
9297	<td style="vertical-align: top;">R(10)<br>
9298
9299
9300
9301
9302	</td>
9303
9304
9305
9306	<td style="vertical-align: top;"><span style="font-style: italic;">10
9307	* 0.0</span><br>
9308
9309
9310
9311	</td>
9312
9313
9314
9315	<td style="vertical-align: top;">Gradient(s) of the initial
9316	profile of the  u-component of the geostrophic wind (in
9317	1/100s).<br>
9318
9319
9320
9321	<br>
9322
9323
9324
9325
9326	The gradient holds starting from the height level defined by <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>
9327	(precisely: for all uv levels k where zu(k) > <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>,
9328	ug(k) is set: ug(k) = ug(k-1) + dzu(k) * <span style="font-weight: bold;">ug_vertical_gradient</span>)
9329	up to the top
9330	boundary or up to the next height level defined by <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>.
9331	A
9332	total of 10 different gradients for 11 height intervals (10
9333	intervals  if <a href="#ug_vertical_gradient_level">ug_vertical_gradient_level</a>(1)
9334	= 0.0) can be assigned. The surface geostrophic wind is assigned by <a href="#ug_surface">ug_surface</a>.<br>
9335
9336
9337
9338	<br>
9339
9340
9341
9342	<span style="font-weight: bold;">Attention:</span><br>
9343
9344
9345
9346	In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>),
9347	the profile is constructed like described above, but starting from the
9348	sea surface (k=nzt) down to the bottom boundary of the model. Height
9349	levels have then to be given as negative values, e.g. <span style="font-weight: bold;">ug_vertical_gradient_level</span> = <span style="font-style: italic;">-500.0</span>, <span style="font-style: italic;">-1000.0</span>.<br>
9350
9351
9352
9353	</td>
9354
9355
9356
9357
9358	</tr>
9359
9360
9361
9362	<tr>
9363
9364
9365
9366	<td style="vertical-align: top;">
9367
9368
9369
9370	<p><a name="ug_vertical_gradient_level"></a><span style="font-weight: bold;">ug_vertical_gradient_level</span></p>
9371
9372
9373
9374
9375	</td>
9376
9377
9378
9379	<td style="vertical-align: top;">R(10)<br>
9380
9381
9382
9383
9384	</td>
9385
9386
9387
9388	<td style="vertical-align: top;"><span style="font-style: italic;">10
9389	* 0.0</span><br>
9390
9391
9392
9393	</td>
9394
9395
9396
9397	<td style="vertical-align: top;">Height level from which on the
9398	gradient defined by <a href="#ug_vertical_gradient">ug_vertical_gradient</a>
9399	is effective (in m).<br>
9400
9401
9402
9403	<br>
9404
9405
9406
9407
9408	The height levels have to be assigned in ascending order. For the
9409	piecewise construction of a profile of the u-component of the
9410	geostrophic wind component (ug) see <a href="#ug_vertical_gradient">ug_vertical_gradient</a>.<br>
9411
9412
9413
9414	<br>
9415
9416
9417
9418	<span style="font-weight: bold;">Attention:</span><br>
9419
9420
9421
9422	In case of ocean runs (see <a href="chapter_4.1.html#ocean">ocean</a>), the (negative) height levels have to be assigned in descending order.</td>
9423
9424
9425
9426	</tr>
9427
9428
9429
9430	<tr>
9431
9432
9433
9434	<td style="vertical-align: top;">
9435
9436
9437
9438	<p><a name="ups_limit_e"></a><b>ups_limit_e</b></p>
9439
9440
9441
9442
9443	</td>
9444
9445
9446
9447	<td style="vertical-align: top;">R</td>
9448
9449
9450
9451
9452	<td style="vertical-align: top;"><i>0.0</i></td>
9453
9454
9455
9456
9457	<td style="vertical-align: top;">
9458
9459
9460
9461	<p>Subgrid-scale
9462	turbulent kinetic energy difference used as
9463	criterion for applying the upstream scheme when upstream-spline
9464	advection is switched on (in m<sup>2</sup>/s<sup>2</sup>).
9465	</p>
9466
9467
9468
9469
9470
9471
9472
9473	<p>This variable steers the appropriate
9474	treatment of the
9475	advection of the subgrid-scale turbulent kinetic energy in case that
9476	the uptream-spline scheme is used . For further information see <a href="#ups_limit_pt">ups_limit_pt</a>.  </p>
9477
9478
9479
9480
9481
9482
9483
9484	<p>Only positive values are allowed for <b>ups_limit_e</b>.
9485	</p>
9486
9487
9488
9489	</td>
9490
9491
9492
9493	</tr>
9494
9495
9496
9497	<tr>
9498
9499
9500
9501	<td style="vertical-align: top;">
9502
9503
9504
9505	<p><a name="ups_limit_pt"></a><b>ups_limit_pt</b></p>
9506
9507
9508
9509
9510	</td>
9511
9512
9513
9514	<td style="vertical-align: top;">R</td>
9515
9516
9517
9518
9519	<td style="vertical-align: top;"><i>0.0</i></td>
9520
9521
9522
9523
9524	<td style="vertical-align: top;">
9525
9526
9527
9528	<p>Temperature
9529	difference used as criterion for applying
9530	the upstream scheme when upstream-spline advection  is
9531	switched on
9532	(in K).  </p>
9533
9534
9535
9536
9537
9538
9539
9540	<p>This criterion is used if the
9541	upstream-spline scheme is
9542	switched on (see <a href="#scalar_advec">scalar_advec</a>).<br>
9543
9544
9545
9546
9547	If, for a given gridpoint, the absolute temperature difference with
9548	respect to the upstream
9549	grid point is smaller than the value given for <b>ups_limit_pt</b>,
9550	the upstream scheme is used for this gridpoint (by default, the
9551	upstream-spline scheme is always used). Reason: in case of a very small
9552	upstream gradient, the advection should cause only a very small
9553	tendency. However, in such situations the upstream-spline scheme may
9554	give wrong tendencies at a
9555	grid point due to spline overshooting, if simultaneously the downstream
9556	gradient is very large. In such cases it may be more reasonable to use
9557	the upstream scheme. The numerical diffusion caused by the upstream
9558	schme remains small as long as the upstream gradients are small.<br>
9559
9560
9561
9562
9563	</p>
9564
9565
9566
9567
9568
9569
9570
9571	<p>The percentage of grid points for which the
9572	upstream
9573	scheme is actually used, can be output as a time series with respect to
9574	the
9575	three directions in space with run parameter (see <a href="chapter_4.2.html#dt_dots">dt_dots</a>, the
9576	timeseries names in the NetCDF file are <i>'splptx'</i>, <i>'splpty'</i>,
9577	<i>'splptz'</i>). The percentage
9578	of gridpoints  should stay below a certain limit, however, it
9579	is
9580	not possible to give
9581	a general limit, since it depends on the respective flow.  </p>
9582
9583
9584
9585
9586
9587
9588
9589	<p>Only positive values are permitted for <b>ups_limit_pt</b>.<br>
9590
9591
9592
9593
9594	</p>
9595
9596
9597
9598
9599	A more effective control of
9600	the “overshoots” can be achieved with parameter <a href="#cut_spline_overshoot">cut_spline_overshoot</a>.
9601	</td>
9602
9603
9604
9605	</tr>
9606
9607
9608
9609	<tr>
9610
9611
9612
9613	<td style="vertical-align: top;">
9614
9615
9616
9617	<p><a name="ups_limit_u"></a><b>ups_limit_u</b></p>
9618
9619
9620
9621
9622	</td>
9623
9624
9625
9626	<td style="vertical-align: top;">R</td>
9627
9628
9629
9630
9631	<td style="vertical-align: top;"><i>0.0</i></td>
9632
9633
9634
9635
9636	<td style="vertical-align: top;">
9637
9638
9639
9640	<p>Velocity
9641	difference (u-component) used as criterion for
9642	applying the upstream scheme
9643	when upstream-spline advection is switched on (in m/s).  </p>
9644
9645
9646
9647
9648
9649
9650
9651	<p>This variable steers the appropriate treatment of the
9652	advection of the u-velocity-component in case that the upstream-spline
9653	scheme is used. For further
9654	information see <a href="#ups_limit_pt">ups_limit_pt</a>.
9655	</p>
9656
9657
9658
9659
9660
9661
9662
9663	<p>Only positive values are permitted for <b>ups_limit_u</b>.</p>
9664
9665
9666
9667
9668	</td>
9669
9670
9671
9672	</tr>
9673
9674
9675
9676	<tr>
9677
9678
9679
9680	<td style="vertical-align: top;">
9681
9682
9683
9684	<p><a name="ups_limit_v"></a><b>ups_limit_v</b></p>
9685
9686
9687
9688
9689	</td>
9690
9691
9692
9693	<td style="vertical-align: top;">R</td>
9694
9695
9696
9697
9698	<td style="vertical-align: top;"><i>0.0</i></td>
9699
9700
9701
9702
9703	<td style="vertical-align: top;">
9704
9705
9706
9707	<p>Velocity
9708	difference (v-component) used as criterion for
9709	applying the upstream scheme
9710	when upstream-spline advection is switched on (in m/s).  </p>
9711
9712
9713
9714
9715
9716
9717
9718	<p>This variable steers the appropriate treatment of the
9719	advection of the v-velocity-component in case that the upstream-spline
9720	scheme is used. For further
9721	information see <a href="#ups_limit_pt">ups_limit_pt</a>.
9722	</p>
9723
9724
9725
9726
9727
9728
9729
9730	<p>Only positive values are permitted for <b>ups_limit_v</b>.</p>
9731
9732
9733
9734
9735	</td>
9736
9737
9738
9739	</tr>
9740
9741
9742
9743	<tr>
9744
9745
9746
9747	<td style="vertical-align: top;">
9748
9749
9750
9751	<p><a name="ups_limit_w"></a><b>ups_limit_w</b></p>
9752
9753
9754
9755
9756	</td>
9757
9758
9759
9760	<td style="vertical-align: top;">R</td>
9761
9762
9763
9764
9765	<td style="vertical-align: top;"><i>0.0</i></td>
9766
9767
9768
9769
9770	<td style="vertical-align: top;">
9771
9772
9773
9774	<p>Velocity
9775	difference (w-component) used as criterion for
9776	applying the upstream scheme
9777	when upstream-spline advection is switched on (in m/s).  </p>
9778