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source: palm/trunk/SOURCE/init_grid.f90 @ 4336

Last change on this file since 4336 was 4329, checked in by motisi, 5 years ago
Renamed wall_flags_0 to wall_flags_static_0
Property svn:keywords set to `Id`
File size: 120.5 KB

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1	!> @file init_grid.f90
2	!------------------------------------------------------------------------------!
3	! This file is part of the PALM model system.
4	!
5	! PALM is free software: you can redistribute it and/or modify it under the
6	! terms of the GNU General Public License as published by the Free Software
7	! Foundation, either version 3 of the License, or (at your option) any later
8	! version.
9	!
10	! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
11	! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
12	! A PARTICULAR PURPOSE. See the GNU General Public License for more details.
13	!
14	! You should have received a copy of the GNU General Public License along with
15	! PALM. If not, see <http://www.gnu.org/licenses/>.
16	!
17	! Copyright 1997-2019 Leibniz Universitaet Hannover
18	!------------------------------------------------------------------------------!
19	!
20	! Current revisions:
21	! -----------------
22	!
23	!
24	! Former revisions:
25	! -----------------
26	! $Id: init_grid.f90 4329 2019-12-10 15:46:36Z raasch $
27	! Renamed wall_flags_0 to wall_flags_static_0
28	!
29	! 4328 2019-12-09 18:53:04Z suehring
30	! Minor change in nzb_max computation. Commentation added.
31	!
32	! 4314 2019-11-29 10:29:20Z suehring
33	! Set additional topography flag 4 to mark topography grid points emerged
34	! from the filtering process.
35	!
36	! 4294 2019-11-13 18:34:16Z suehring
37	! Bugfix, always set bit 5 and 6 of wall_flags, indicating terrain- and
38	! building surfaces in all cases, in order to enable terrain-following output
39	! also when no land- or urban-surface model is applied.
40	!
41	! 4265 2019-10-15 16:16:24Z suehring
42	! Bugfix for last commit, exchange oro_max variable only when it is allocated
43	! (not necessarily the case when topography is input from ASCII file).
44	!
45	! 4245 2019-09-30 08:40:37Z pavelkrc
46	! Store oro_max (building z-offset) in 2D for building surfaces
47	!
48	! 4189 2019-08-26 16:19:38Z suehring
49	! - Add check for proper setting of namelist parameter topography
50	! - Set flag to indicate land surfaces in case no topography is provided
51	!
52	! 4182 2019-08-22 15:20:23Z scharf
53	! Corrected "Former revisions" section
54	!
55	! 4168 2019-08-16 13:50:17Z suehring
56	! Pre-calculate topography top index and store it on an array (replaces former
57	! functions get_topography_top_index)
58	!
59	! 4159 2019-08-15 13:31:35Z suehring
60	! Revision of topography processing. This was not consistent between 2D and 3D
61	! buildings.
62	!
63	! 4144 2019-08-06 09:11:47Z raasch
64	! relational operators .EQ., .NE., etc. replaced by ==, /=, etc.
65	!
66	! 4115 2019-07-24 12:50:49Z suehring
67	! Bugfix in setting near-surface flag 24, inidicating wall-bounded grid points
68	!
69	! 4110 2019-07-22 17:05:21Z suehring
70	! - Separate initialization of advection flags for momentum and scalars.
71	! - Change subroutine interface for ws_init_flags_scalar to pass boundary flags
72	!
73	! 4109 2019-07-22 17:00:34Z suehring
74	! Fix bad commit
75	!
76	! 3926 2019-04-23 12:56:42Z suehring
77	! Minor bugfix in building mapping when all building IDs in the model domain
78	! are missing
79	!
80	! 3857 2019-04-03 13:00:16Z knoop
81	! In projection of non-building 3D objects onto numerical grid remove
82	! dependency on building_type
83	!
84	! 3763 2019-02-25 17:33:49Z suehring
85	! Replace work-around for ghost point exchange of 1-byte arrays with specific
86	! routine as already done in other routines
87	!
88	! 3761 2019-02-25 15:31:42Z raasch
89	! unused variables removed
90	!
91	! 3661 2019-01-08 18:22:50Z suehring
92	! Remove setting of nzb_max to nzt at non-cyclic boundary PEs, instead,
93	! order degradation of advection scheme is handeled directly in advec_ws
94	!
95	! 3655 2019-01-07 16:51:22Z knoop
96	! Comment added
97	!
98	! Revision 1.1 1997/08/11 06:17:45 raasch
99	! Initial revision (Testversion)
100	!
101	!
102	! Description:
103	! -----------------------------------------------------------------------------!
104	!> Creating grid depending constants
105	!> @todo: Rearrange topo flag list
106	!> @todo: reference 3D buildings on top of orography is not tested and may need
107	!> further improvement for steep slopes
108	!> @todo: Use more advanced setting of building type at filled holes
109	!------------------------------------------------------------------------------!
110	SUBROUTINE init_grid
111
112	USE advec_ws, &
113	ONLY: ws_init_flags_momentum, ws_init_flags_scalar
114
115	USE arrays_3d, &
116	ONLY: dd2zu, ddzu, ddzu_pres, ddzw, dzu, dzw, x, xu, y, yv, zu, zw
117
118	USE control_parameters, &
119	ONLY: bc_lr_cyc, bc_ns_cyc, &
120	bc_dirichlet_l, &
121	bc_dirichlet_n, &
122	bc_dirichlet_r, &
123	bc_dirichlet_s, &
124	bc_radiation_l, &
125	bc_radiation_n, &
126	bc_radiation_r, &
127	bc_radiation_s, &
128	constant_flux_layer, dz, dz_max, dz_stretch_factor, &
129	dz_stretch_factor_array, dz_stretch_level, dz_stretch_level_end,&
130	dz_stretch_level_end_index, dz_stretch_level_start_index, &
131	dz_stretch_level_start, ibc_uv_b, message_string, &
132	momentum_advec, number_stretch_level_end, &
133	number_stretch_level_start, ocean_mode, psolver, scalar_advec, &
134	topography, use_surface_fluxes
135
136	USE grid_variables, &
137	ONLY: ddx, ddx2, ddy, ddy2, dx, dx2, dy, dy2, zu_s_inner, zw_w_inner
138
139	USE indices, &
140	ONLY: advc_flags_m, &
141	advc_flags_s, &
142	nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
143	nzb, nzb_diff, nzb_diff_s_inner, nzb_diff_s_outer, &
144	nzb_max, nzb_s_inner, nzb_s_outer, nzb_u_inner, &
145	nzb_u_outer, nzb_v_inner, nzb_v_outer, nzb_w_inner, &
146	nzb_w_outer, nzt, topo_top_ind, topo_min_level
147
148	USE kinds
149
150	USE pegrid
151
152	USE poismg_noopt_mod
153
154	USE surface_mod, &
155	ONLY: init_bc
156
157	USE vertical_nesting_mod, &
158	ONLY: vnested, vnest_init_grid
159
160	IMPLICIT NONE
161
162	INTEGER(iwp) :: i !< index variable along x
163	INTEGER(iwp) :: j !< index variable along y
164	INTEGER(iwp) :: k !< index variable along z
165	INTEGER(iwp) :: k_top !< topography top index on local PE
166	INTEGER(iwp) :: n !< loop variable for stretching
167	INTEGER(iwp) :: number_dz !< number of user-specified dz values
168	INTEGER(iwp) :: nzb_local_max !< vertical grid index of maximum topography height
169	INTEGER(iwp) :: nzb_local_min !< vertical grid index of minimum topography height
170
171	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
172	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_tmp !< dummy to calculate topography indices on u- and v-grid
173
174	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
175
176	REAL(wp) :: dz_level_end !< distance between calculated height level for u/v-grid and user-specified end level for stretching
177	REAL(wp) :: dz_stretched !< stretched vertical grid spacing
178
179	REAL(wp), DIMENSION(:), ALLOCATABLE :: min_dz_stretch_level_end !< Array that contains all minimum heights where the stretching can end
180
181
182	!
183	!-- Calculation of horizontal array bounds including ghost layers
184	nxlg = nxl - nbgp
185	nxrg = nxr + nbgp
186	nysg = nys - nbgp
187	nyng = nyn + nbgp
188
189	!
190	!-- Allocate grid arrays
191	ALLOCATE( x(0:nx), xu(0:nx) )
192	DO i = 0, nx
193	xu(i) = i * dx
194	x(i) = i * dx + 0.5_wp * dx
195	ENDDO
196
197	ALLOCATE( y(0:ny), yv(0:ny) )
198	DO j = 0, ny
199	yv(j) = j * dy
200	y(j) = j * dy + 0.5_wp * dy
201	ENDDO
202
203	!
204	!-- Allocate grid arrays
205	ALLOCATE( ddzu(1:nzt+1), ddzw(1:nzt+1), dd2zu(1:nzt), dzu(1:nzt+1), &
206	dzw(1:nzt+1), zu(nzb:nzt+1), zw(nzb:nzt+1) )
207
208	!
209	!-- Compute height of u-levels from constant grid length and dz stretch factors
210	IF ( dz(1) == -1.0_wp ) THEN
211	message_string = 'missing dz'
212	CALL message( 'init_grid', 'PA0200', 1, 2, 0, 6, 0 )
213	ELSEIF ( dz(1) <= 0.0_wp ) THEN
214	WRITE( message_string, * ) 'dz=',dz(1),' <= 0.0'
215	CALL message( 'init_grid', 'PA0201', 1, 2, 0, 6, 0 )
216	ENDIF
217
218	!
219	!-- Initialize dz_stretch_level_start with the value of dz_stretch_level
220	!-- if it was set by the user
221	IF ( dz_stretch_level /= -9999999.9_wp ) THEN
222	dz_stretch_level_start(1) = dz_stretch_level
223	ENDIF
224
225	!
226	!-- Determine number of dz values and stretching levels specified by the
227	!-- user to allow right controlling of the stretching mechanism and to
228	!-- perform error checks. The additional requirement that dz /= dz_max
229	!-- for counting number of user-specified dz values is necessary. Otherwise
230	!-- restarts would abort if the old stretching mechanism with dz_stretch_level
231	!-- is used (Attention: The user is not allowed to specify a dz value equal
232	!-- to the default of dz_max = 999.0).
233	number_dz = COUNT( dz /= -1.0_wp .AND. dz /= dz_max)
234	number_stretch_level_start = COUNT( dz_stretch_level_start /= &
235	-9999999.9_wp )
236	number_stretch_level_end = COUNT( dz_stretch_level_end /= &
237	9999999.9_wp )
238
239	!
240	!-- The number of specified end levels +1 has to be the same than the number
241	!-- of specified dz values
242	IF ( number_dz /= number_stretch_level_end + 1 ) THEN
243	WRITE( message_string, * ) 'The number of values for dz = ', &
244	number_dz, 'has to be the same than& ', &
245	'the number of values for ', &
246	'dz_stretch_level_end + 1 = ', &
247	number_stretch_level_end+1
248	CALL message( 'init_grid', 'PA0156', 1, 2, 0, 6, 0 )
249	ENDIF
250
251	!
252	!-- The number of specified start levels has to be the same or one less than
253	!-- the number of specified dz values
254	IF ( number_dz /= number_stretch_level_start + 1 .AND. &
255	number_dz /= number_stretch_level_start ) THEN
256	WRITE( message_string, * ) 'The number of values for dz = ', &
257	number_dz, 'has to be the same or one ', &
258	'more than& the number of values for ', &
259	'dz_stretch_level_start = ', &
260	number_stretch_level_start
261	CALL message( 'init_grid', 'PA0211', 1, 2, 0, 6, 0 )
262	ENDIF
263
264	!-- The number of specified start levels has to be the same or one more than
265	!-- the number of specified end levels
266	IF ( number_stretch_level_start /= number_stretch_level_end + 1 .AND. &
267	number_stretch_level_start /= number_stretch_level_end ) THEN
268	WRITE( message_string, * ) 'The number of values for ', &
269	'dz_stretch_level_start = ', &
270	dz_stretch_level_start, 'has to be the ',&
271	'same or one more than& the number of ', &
272	'values for dz_stretch_level_end = ', &
273	number_stretch_level_end
274	CALL message( 'init_grid', 'PA0216', 1, 2, 0, 6, 0 )
275	ENDIF
276
277	!
278	!-- Initialize dz for the free atmosphere with the value of dz_max
279	IF ( dz(number_stretch_level_start+1) == -1.0_wp .AND. &
280	number_stretch_level_start /= 0 ) THEN
281	dz(number_stretch_level_start+1) = dz_max
282	ENDIF
283
284	!
285	!-- Initialize the stretching factor if (infinitely) stretching in the free
286	!-- atmosphere is desired (dz_stretch_level_end was not specified for the
287	!-- free atmosphere)
288	IF ( number_stretch_level_start == number_stretch_level_end + 1 ) THEN
289	dz_stretch_factor_array(number_stretch_level_start) = &
290	dz_stretch_factor
291	ENDIF
292
293	!
294	!-- Allocation of arrays for stretching
295	ALLOCATE( min_dz_stretch_level_end(number_stretch_level_start) )
296
297	!
298	!-- Define the vertical grid levels
299	IF ( .NOT. ocean_mode ) THEN
300
301	!
302	!-- The stretching region has to be large enough to allow for a smooth
303	!-- transition between two different grid spacings
304	DO n = 1, number_stretch_level_start
305	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) + &
306	4 * MAX( dz(n),dz(n+1) )
307	ENDDO
308
309	IF ( ANY( min_dz_stretch_level_end(1:number_stretch_level_start) > &
310	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
311	message_string= 'Eeach dz_stretch_level_end has to be larger ' // &
312	'than its corresponding value for &' // &
313	'dz_stretch_level_start + 4*MAX(dz(n),dz(n+1)) '//&
314	'to allow for smooth grid stretching'
315	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
316	ENDIF
317
318	!
319	!-- Stretching must not be applied within the prandtl_layer
320	!-- (first two grid points). For the default case dz_stretch_level_start
321	!-- is negative. Therefore the absolut value is checked here.
322	IF ( ANY( ABS( dz_stretch_level_start ) < dz(1) * 1.5_wp ) ) THEN
323	WRITE( message_string, * ) 'Eeach dz_stretch_level_start has to be ',&
324	'larger than ', dz(1) * 1.5
325	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
326	ENDIF
327
328	!
329	!-- The stretching has to start and end on a grid level. Therefore
330	!-- user-specified values have to ''interpolate'' to the next lowest level
331	IF ( number_stretch_level_start /= 0 ) THEN
332	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) - &
333	dz(1)/2.0) / dz(1) ) &
334	* dz(1) + dz(1)/2.0
335	ENDIF
336
337	IF ( number_stretch_level_start > 1 ) THEN
338	DO n = 2, number_stretch_level_start
339	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
340	dz(n) ) * dz(n)
341	ENDDO
342	ENDIF
343
344	IF ( number_stretch_level_end /= 0 ) THEN
345	DO n = 1, number_stretch_level_end
346	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
347	dz(n+1) ) * dz(n+1)
348	ENDDO
349	ENDIF
350
351	!
352	!-- Determine stretching factor if necessary
353	IF ( number_stretch_level_end >= 1 ) THEN
354	CALL calculate_stretching_factor( number_stretch_level_end )
355	ENDIF
356
357	!
358	!-- Grid for atmosphere with surface at z=0 (k=0, w-grid).
359	!-- First compute the u- and v-levels. In case of dirichlet bc for u and v
360	!-- the first u/v- and w-level (k=0) are defined at same height (z=0).
361	!-- The second u-level (k=1) corresponds to the top of the
362	!-- Prandtl-layer.
363	IF ( ibc_uv_b == 0 .OR. ibc_uv_b == 2 ) THEN
364	zu(0) = 0.0_wp
365	ELSE
366	zu(0) = - dz(1) * 0.5_wp
367	ENDIF
368
369	zu(1) = dz(1) * 0.5_wp
370
371	!
372	!-- Determine u and v height levels considering the possibility of grid
373	!-- stretching in several heights.
374	n = 1
375	dz_stretch_level_start_index = nzt+1
376	dz_stretch_level_end_index = nzt+1
377	dz_stretched = dz(1)
378
379	!-- The default value of dz_stretch_level_start is negative, thus the first
380	!-- condition is always true. Hence, the second condition is necessary.
381	DO k = 2, nzt+1
382	IF ( dz_stretch_level_start(n) <= zu(k-1) .AND. &
383	dz_stretch_level_start(n) /= -9999999.9_wp ) THEN
384	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
385
386	IF ( dz(n) > dz(n+1) ) THEN
387	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
388	ELSE
389	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
390	ENDIF
391
392	IF ( dz_stretch_level_start_index(n) == nzt+1 ) &
393	dz_stretch_level_start_index(n) = k-1
394
395	ENDIF
396
397	zu(k) = zu(k-1) + dz_stretched
398
399	!
400	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
401	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
402
403	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
404	zu(k) = dz_stretch_level_end(n)
405	dz_stretched = dz(n+1)
406	dz_stretch_level_end_index(n) = k
407	n = n + 1
408	ENDIF
409	ENDDO
410
411	!
412	!-- Compute the w-levels. They are always staggered half-way between the
413	!-- corresponding u-levels. In case of dirichlet bc for u and v at the
414	!-- ground the first u- and w-level (k=0) are defined at same height (z=0).
415	!-- The top w-level is extrapolated linearly.
416	zw(0) = 0.0_wp
417	DO k = 1, nzt
418	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
419	ENDDO
420	zw(nzt+1) = zw(nzt) + 2.0_wp * ( zu(nzt+1) - zw(nzt) )
421
422	ELSE
423
424	!
425	!-- The stretching region has to be large enough to allow for a smooth
426	!-- transition between two different grid spacings
427	DO n = 1, number_stretch_level_start
428	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) - &
429	4 * MAX( dz(n),dz(n+1) )
430	ENDDO
431
432	IF ( ANY( min_dz_stretch_level_end (1:number_stretch_level_start) < &
433	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
434	message_string= 'Eeach dz_stretch_level_end has to be less ' // &
435	'than its corresponding value for &' // &
436	'dz_stretch_level_start - 4*MAX(dz(n),dz(n+1)) '//&
437	'to allow for smooth grid stretching'
438	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
439	ENDIF
440
441	!
442	!-- Stretching must not be applied close to the surface (last two grid
443	!-- points). For the default case dz_stretch_level_start is negative.
444	IF ( ANY( dz_stretch_level_start > - dz(1) * 1.5_wp ) ) THEN
445	WRITE( message_string, * ) 'Eeach dz_stretch_level_start has to be ',&
446	'less than ', dz(1) * 1.5
447	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
448	ENDIF
449
450	!
451	!-- The stretching has to start and end on a grid level. Therefore
452	!-- user-specified values have to ''interpolate'' to the next highest level
453	IF ( number_stretch_level_start /= 0 ) THEN
454	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) + &
455	dz(1)/2.0) / dz(1) ) &
456	* dz(1) - dz(1)/2.0
457	ENDIF
458
459	IF ( number_stretch_level_start > 1 ) THEN
460	DO n = 2, number_stretch_level_start
461	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
462	dz(n) ) * dz(n)
463	ENDDO
464	ENDIF
465
466	IF ( number_stretch_level_end /= 0 ) THEN
467	DO n = 1, number_stretch_level_end
468	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
469	dz(n+1) ) * dz(n+1)
470	ENDDO
471	ENDIF
472
473	!
474	!-- Determine stretching factor if necessary
475	IF ( number_stretch_level_end >= 1 ) THEN
476	CALL calculate_stretching_factor( number_stretch_level_end )
477	ENDIF
478
479	!
480	!-- Grid for ocean with free water surface is at k=nzt (w-grid).
481	!-- In case of neumann bc at the ground the first first u-level (k=0) lies
482	!-- below the first w-level (k=0). In case of dirichlet bc the first u- and
483	!-- w-level are defined at same height, but staggered from the second level.
484	!-- The second u-level (k=1) corresponds to the top of the Prandtl-layer.
485	!-- z values are negative starting from z=0 (surface)
486	zu(nzt+1) = dz(1) * 0.5_wp
487	zu(nzt) = - dz(1) * 0.5_wp
488
489	!
490	!-- Determine u and v height levels considering the possibility of grid
491	!-- stretching in several heights.
492	n = 1
493	dz_stretch_level_start_index = 0
494	dz_stretch_level_end_index = 0
495	dz_stretched = dz(1)
496
497	DO k = nzt-1, 0, -1
498
499	IF ( dz_stretch_level_start(n) >= zu(k+1) ) THEN
500	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
501
502	IF ( dz(n) > dz(n+1) ) THEN
503	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
504	ELSE
505	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
506	ENDIF
507
508	IF ( dz_stretch_level_start_index(n) == 0 ) &
509	dz_stretch_level_start_index(n) = k+1
510
511	ENDIF
512
513	zu(k) = zu(k+1) - dz_stretched
514
515	!
516	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
517	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
518
519	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
520	zu(k) = dz_stretch_level_end(n)
521	dz_stretched = dz(n+1)
522	dz_stretch_level_end_index(n) = k
523	n = n + 1
524	ENDIF
525	ENDDO
526
527	!
528	!-- Compute the w-levels. They are always staggered half-way between the
529	!-- corresponding u-levels, except in case of dirichlet bc for u and v
530	!-- at the ground. In this case the first u- and w-level are defined at
531	!-- same height. The top w-level (nzt+1) is not used but set for
532	!-- consistency, since w and all scalar variables are defined up tp nzt+1.
533	zw(nzt+1) = dz(1)
534	zw(nzt) = 0.0_wp
535	DO k = 0, nzt
536	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
537	ENDDO
538
539	!
540	!-- In case of dirichlet bc for u and v the first u- and w-level are defined
541	!-- at same height.
542	IF ( ibc_uv_b == 0 ) THEN
543	zu(0) = zw(0)
544	ENDIF
545
546	ENDIF
547
548	!
549	!-- Compute grid lengths.
550	DO k = 1, nzt+1
551	dzu(k) = zu(k) - zu(k-1)
552	ddzu(k) = 1.0_wp / dzu(k)
553	dzw(k) = zw(k) - zw(k-1)
554	ddzw(k) = 1.0_wp / dzw(k)
555	ENDDO
556
557	DO k = 1, nzt
558	dd2zu(k) = 1.0_wp / ( dzu(k) + dzu(k+1) )
559	ENDDO
560
561	!
562	!-- The FFT- SOR-pressure solvers assume grid spacings of a staggered grid
563	!-- everywhere. For the actual grid, the grid spacing at the lowest level
564	!-- is only dz/2, but should be dz. Therefore, an additional array
565	!-- containing with appropriate grid information is created for these
566	!-- solvers.
567	IF ( psolver(1:9) /= 'multigrid' ) THEN
568	ALLOCATE( ddzu_pres(1:nzt+1) )
569	ddzu_pres = ddzu
570	ddzu_pres(1) = ddzu_pres(2) ! change for lowest level
571	ENDIF
572
573	!
574	!-- Compute the reciprocal values of the horizontal grid lengths.
575	ddx = 1.0_wp / dx
576	ddy = 1.0_wp / dy
577	dx2 = dx * dx
578	dy2 = dy * dy
579	ddx2 = 1.0_wp / dx2
580	ddy2 = 1.0_wp / dy2
581
582	!
583	!-- Allocate 3D array to set topography
584	ALLOCATE( topo(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
585	topo = 0
586	!
587	!-- Initialize topography by generic topography or read from topography from file.
588	CALL init_topo( topo )
589	!
590	!-- Set flags to mask topography on the grid.
591	CALL set_topo_flags( topo )
592	!
593	!-- Calculate wall flag arrays for the multigrid method.
594	!-- Please note, wall flags are only applied in the non-optimized version.
595	IF ( psolver == 'multigrid_noopt' ) CALL poismg_noopt_init
596
597	!
598	!-- Init flags for ws-scheme to degrade order of the numerics near walls, i.e.
599	!-- to decrease the numerical stencil appropriately. The order of the scheme
600	!-- is degraded near solid walls as well as near non-cyclic inflow and outflow
601	!-- boundaries. Do this separately for momentum and scalars.
602	IF ( momentum_advec == 'ws-scheme' ) THEN
603	ALLOCATE( advc_flags_m(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
604	CALL ws_init_flags_momentum
605	ENDIF
606	IF ( scalar_advec == 'ws-scheme' ) THEN
607	ALLOCATE( advc_flags_s(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
608	advc_flags_s = 0
609
610	CALL ws_init_flags_scalar( bc_dirichlet_l .OR. bc_radiation_l, &
611	bc_dirichlet_n .OR. bc_radiation_n, &
612	bc_dirichlet_r .OR. bc_radiation_r, &
613	bc_dirichlet_s .OR. bc_radiation_s, &
614	advc_flags_s )
615	ENDIF
616
617	!
618	!-- Determine the maximum level of topography. It is used for
619	!-- steering the degradation of order of the applied advection scheme,
620	!-- as well in the lpm.
621	k_top = 0
622	DO i = nxl, nxr
623	DO j = nys, nyn
624	DO k = nzb, nzt + 1
625	k_top = MAX( k_top, MERGE( k, 0, .NOT. BTEST( topo(k,j,i), 0 ) ) )
626	ENDDO
627	ENDDO
628	ENDDO
629	#if defined( __parallel )
630	CALL MPI_ALLREDUCE( k_top, nzb_max, 1, MPI_INTEGER, &
631	MPI_MAX, comm2d, ierr )
632	#else
633	nzb_max = k_top
634	#endif
635	!
636	!-- Increment nzb_max by 1 in order to allow for proper diverengence correction.
637	!-- Further, in case topography extents up to the model top, limit to nzt.
638	nzb_max = MIN( nzb_max+1, nzt )
639	!
640	!-- Determine minimum index of topography. Usually, this will be nzb. In case
641	!-- there is elevated topography, however, the lowest topography will be higher.
642	!-- This index is e.g. used to calculate mean first-grid point atmosphere
643	!-- temperature, surface pressure and density, etc. .
644	topo_min_level = 0
645	#if defined( __parallel )
646	CALL MPI_ALLREDUCE( MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
647	topo_min_level, 1, MPI_INTEGER, MPI_MIN, comm2d, ierr )
648	#else
649	topo_min_level = MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
650	#endif
651	!
652	!-- Initialize boundary conditions via surface type
653	CALL init_bc
654
655	!
656	!-- Allocate and set topography height arrays required for data output
657	IF ( TRIM( topography ) /= 'flat' ) THEN
658	!
659	!-- Allocate and set the arrays containing the topography height
660	IF ( nxr == nx .AND. nyn /= ny ) THEN
661	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn), &
662	zw_w_inner(nxl:nxr+1,nys:nyn) )
663	ELSEIF ( nxr /= nx .AND. nyn == ny ) THEN
664	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn+1), &
665	zw_w_inner(nxl:nxr,nys:nyn+1) )
666	ELSEIF ( nxr == nx .AND. nyn == ny ) THEN
667	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn+1), &
668	zw_w_inner(nxl:nxr+1,nys:nyn+1) )
669	ELSE
670	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn), &
671	zw_w_inner(nxl:nxr,nys:nyn) )
672	ENDIF
673
674	zu_s_inner = 0.0_wp
675	zw_w_inner = 0.0_wp
676	!
677	!-- Determine local topography height on scalar and w-grid. Note, setting
678	!-- lateral boundary values is not necessary, realized via wall_flags_static_0
679	!-- array. Further, please note that loop bounds are different from
680	!-- nxl to nxr and nys to nyn on south and right model boundary, hence,
681	!-- use intrinsic lbound and ubound functions to infer array bounds.
682	DO i = LBOUND(zu_s_inner, 1), UBOUND(zu_s_inner, 1)
683	DO j = LBOUND(zu_s_inner, 2), UBOUND(zu_s_inner, 2)
684	!
685	!-- Topography height on scalar grid. Therefore, determine index of
686	!-- upward-facing surface element on scalar grid.
687	zu_s_inner(i,j) = zu(topo_top_ind(j,i,0))
688	!
689	!-- Topography height on w grid. Therefore, determine index of
690	!-- upward-facing surface element on w grid.
691	zw_w_inner(i,j) = zw(topo_top_ind(j,i,3))
692	ENDDO
693	ENDDO
694	ENDIF
695
696	!
697	!-- In the following, calculate 2D index arrays. Note, these will be removed
698	!-- soon.
699	!-- Allocate outer and inner index arrays for topography and set
700	!-- defaults.
701	ALLOCATE( nzb_s_inner(nysg:nyng,nxlg:nxrg), &
702	nzb_s_outer(nysg:nyng,nxlg:nxrg), &
703	nzb_u_inner(nysg:nyng,nxlg:nxrg), &
704	nzb_u_outer(nysg:nyng,nxlg:nxrg), &
705	nzb_v_inner(nysg:nyng,nxlg:nxrg), &
706	nzb_v_outer(nysg:nyng,nxlg:nxrg), &
707	nzb_w_inner(nysg:nyng,nxlg:nxrg), &
708	nzb_w_outer(nysg:nyng,nxlg:nxrg), &
709	nzb_diff_s_inner(nysg:nyng,nxlg:nxrg), &
710	nzb_diff_s_outer(nysg:nyng,nxlg:nxrg), &
711	nzb_local(nysg:nyng,nxlg:nxrg), &
712	nzb_tmp(nysg:nyng,nxlg:nxrg) )
713	!
714	!-- Initialize 2D-index arrays. Note, these will be removed soon!
715	nzb_local(nys:nyn,nxl:nxr) = topo_top_ind(nys:nyn,nxl:nxr,0)
716	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
717	!
718	!-- Check topography for consistency with model domain. Therefore, use
719	!-- maximum and minium topography-top indices. Note, minimum topography top
720	!-- index is already calculated.
721	IF ( TRIM( topography ) /= 'flat' ) THEN
722	#if defined( __parallel )
723	CALL MPI_ALLREDUCE( MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
724	nzb_local_max, 1, MPI_INTEGER, MPI_MAX, comm2d, ierr )
725	#else
726	nzb_local_max = MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
727	#endif
728	nzb_local_min = topo_min_level
729	!
730	!-- Consistency checks
731	IF ( nzb_local_min < 0 .OR. nzb_local_max > nz + 1 ) THEN
732	WRITE( message_string, * ) 'nzb_local values are outside the', &
733	' model domain', &
734	'&MINVAL( nzb_local ) = ', nzb_local_min, &
735	'&MAXVAL( nzb_local ) = ', nzb_local_max
736	CALL message( 'init_grid', 'PA0210', 1, 2, 0, 6, 0 )
737	ENDIF
738	ENDIF
739
740	nzb_s_inner = nzb; nzb_s_outer = nzb
741	nzb_u_inner = nzb; nzb_u_outer = nzb
742	nzb_v_inner = nzb; nzb_v_outer = nzb
743	nzb_w_inner = nzb; nzb_w_outer = nzb
744
745	!
746	!-- Define vertical gridpoint from (or to) which on the usual finite difference
747	!-- form (which does not use surface fluxes) is applied
748	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
749	nzb_diff = nzb + 2
750	ELSE
751	nzb_diff = nzb + 1
752	ENDIF
753
754	nzb_diff_s_inner = nzb_diff; nzb_diff_s_outer = nzb_diff
755	!
756	!-- Set Neumann conditions for topography. Will be removed soon.
757	IF ( .NOT. bc_ns_cyc ) THEN
758	IF ( nys == 0 ) THEN
759	DO i = 1, nbgp
760	nzb_local(nys-i,:) = nzb_local(nys,:)
761	ENDDO
762	ELSEIF ( nyn == ny ) THEN
763	DO i = 1, nbgp
764	nzb_local(ny+i,:) = nzb_local(ny,:)
765	ENDDO
766	ENDIF
767	ENDIF
768
769	IF ( .NOT. bc_lr_cyc ) THEN
770	IF ( nxl == 0 ) THEN
771	DO i = 1, nbgp
772	nzb_local(:,nxl-i) = nzb_local(:,nxl)
773	ENDDO
774	ELSEIF ( nxr == nx ) THEN
775	DO i = 1, nbgp
776	nzb_local(:,nx+i) = nzb_local(:,nx)
777	ENDDO
778	ENDIF
779	ENDIF
780	!
781	!-- Initialization of 2D index arrays, will be removed soon!
782	!-- Initialize nzb_s_inner and nzb_w_inner
783	nzb_s_inner = nzb_local
784	nzb_w_inner = nzb_local
785
786	!
787	!-- Initialize remaining index arrays:
788	!-- first pre-initialize them with nzb_s_inner...
789	nzb_u_inner = nzb_s_inner
790	nzb_u_outer = nzb_s_inner
791	nzb_v_inner = nzb_s_inner
792	nzb_v_outer = nzb_s_inner
793	nzb_w_outer = nzb_s_inner
794	nzb_s_outer = nzb_s_inner
795
796	!
797	!-- nzb_s_outer:
798	!-- extend nzb_local east-/westwards first, then north-/southwards
799	nzb_tmp = nzb_local
800	DO j = nys, nyn
801	DO i = nxl, nxr
802	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i), &
803	nzb_local(j,i+1) )
804	ENDDO
805	ENDDO
806
807	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
808
809	DO i = nxl, nxr
810	DO j = nys, nyn
811	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
812	nzb_tmp(j+1,i) )
813	ENDDO
814	!
815	!-- non-cyclic boundary conditions (overwritten by call of
816	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
817	IF ( nys == 0 ) THEN
818	j = -1
819	nzb_s_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
820	ENDIF
821	IF ( nyn == ny ) THEN
822	j = ny + 1
823	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
824	ENDIF
825	ENDDO
826	!
827	!-- nzb_w_outer:
828	!-- identical to nzb_s_outer
829	nzb_w_outer = nzb_s_outer
830	!
831	!-- nzb_u_inner:
832	!-- extend nzb_local rightwards only
833	nzb_tmp = nzb_local
834	DO j = nys, nyn
835	DO i = nxl, nxr
836	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i) )
837	ENDDO
838	ENDDO
839
840	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
841
842	nzb_u_inner = nzb_tmp
843	!
844	!-- nzb_u_outer:
845	!-- extend current nzb_tmp (nzb_u_inner) north-/southwards
846	DO i = nxl, nxr
847	DO j = nys, nyn
848	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
849	nzb_tmp(j+1,i) )
850	ENDDO
851	!
852	!-- non-cyclic boundary conditions (overwritten by call of
853	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
854	IF ( nys == 0 ) THEN
855	j = -1
856	nzb_u_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
857	ENDIF
858	IF ( nyn == ny ) THEN
859	j = ny + 1
860	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
861	ENDIF
862	ENDDO
863
864	!
865	!-- nzb_v_inner:
866	!-- extend nzb_local northwards only
867	nzb_tmp = nzb_local
868	DO i = nxl, nxr
869	DO j = nys, nyn
870	nzb_tmp(j,i) = MAX( nzb_local(j-1,i), nzb_local(j,i) )
871	ENDDO
872	ENDDO
873
874	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
875	nzb_v_inner = nzb_tmp
876
877	!
878	!-- nzb_v_outer:
879	!-- extend current nzb_tmp (nzb_v_inner) right-/leftwards
880	DO j = nys, nyn
881	DO i = nxl, nxr
882	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i), &
883	nzb_tmp(j,i+1) )
884	ENDDO
885	!
886	!-- non-cyclic boundary conditions (overwritten by call of
887	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
888	IF ( nxl == 0 ) THEN
889	i = -1
890	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i+1), nzb_tmp(j,i) )
891	ENDIF
892	IF ( nxr == nx ) THEN
893	i = nx + 1
894	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i) )
895	ENDIF
896	ENDDO
897
898	!
899	!-- Exchange of lateral boundary values (parallel computers) and cyclic
900	!-- boundary conditions, if applicable.
901	!-- Since nzb_s_inner and nzb_w_inner are derived directly from nzb_local
902	!-- they do not require exchange and are not included here.
903	CALL exchange_horiz_2d_int( nzb_u_inner, nys, nyn, nxl, nxr, nbgp )
904	CALL exchange_horiz_2d_int( nzb_u_outer, nys, nyn, nxl, nxr, nbgp )
905	CALL exchange_horiz_2d_int( nzb_v_inner, nys, nyn, nxl, nxr, nbgp )
906	CALL exchange_horiz_2d_int( nzb_v_outer, nys, nyn, nxl, nxr, nbgp )
907	CALL exchange_horiz_2d_int( nzb_w_outer, nys, nyn, nxl, nxr, nbgp )
908	CALL exchange_horiz_2d_int( nzb_s_outer, nys, nyn, nxl, nxr, nbgp )
909
910	!
911	!-- Set the individual index arrays which define the k index from which on
912	!-- the usual finite difference form (which does not use surface fluxes) is
913	!-- applied
914	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
915	nzb_diff_s_inner = nzb_s_inner + 2
916	nzb_diff_s_outer = nzb_s_outer + 2
917	ELSE
918	nzb_diff_s_inner = nzb_s_inner + 1
919	nzb_diff_s_outer = nzb_s_outer + 1
920	ENDIF
921	!
922	!-- Vertical nesting: communicate vertical grid level arrays between fine and
923	!-- coarse grid
924	IF ( vnested ) CALL vnest_init_grid
925
926	END SUBROUTINE init_grid
927
928
929	! Description:
930	! -----------------------------------------------------------------------------!
931	!> Calculation of the stretching factor through an iterative method. Ideas were
932	!> taken from the paper "Regional stretched grid generation and its application
933	!> to the NCAR RegCM (1999)". Normally, no analytic solution exists because the
934	!> system of equations has two variables (r,l) but four requirements
935	!> (l=integer, r=[0,88;1,2], Eq(6), Eq(5) starting from index j=1) which
936	!> results into an overdetermined system.
937	!------------------------------------------------------------------------------!
938	SUBROUTINE calculate_stretching_factor( number_end )
939
940	USE control_parameters, &
941	ONLY: dz, dz_stretch_factor_array, &
942	dz_stretch_level_end, dz_stretch_level_start, message_string
943
944	USE kinds
945
946	IMPLICIT NONE
947
948	INTEGER(iwp) :: iterations !< number of iterations until stretch_factor_lower/upper_limit is reached
949	INTEGER(iwp) :: l_rounded !< after l_rounded grid levels dz(n) is strechted to dz(n+1) with stretch_factor_2
950	INTEGER(iwp) :: n !< loop variable for stretching
951
952	INTEGER(iwp), INTENT(IN) :: number_end !< number of user-specified end levels for stretching
953
954	REAL(wp) :: delta_l !< absolute difference between l and l_rounded
955	REAL(wp) :: delta_stretch_factor !< absolute difference between stretch_factor_1 and stretch_factor_2
956	REAL(wp) :: delta_total_new !< sum of delta_l and delta_stretch_factor for the next iteration (should be as small as possible)
957	REAL(wp) :: delta_total_old !< sum of delta_l and delta_stretch_factor for the last iteration
958	REAL(wp) :: distance !< distance between dz_stretch_level_start and dz_stretch_level_end (stretching region)
959	REAL(wp) :: l !< value that fulfil Eq. (5) in the paper mentioned above together with stretch_factor_1 exactly
960	REAL(wp) :: numerator !< numerator of the quotient
961	REAL(wp) :: stretch_factor_1 !< stretching factor that fulfil Eq. (5) togehter with l exactly
962	REAL(wp) :: stretch_factor_2 !< stretching factor that fulfil Eq. (6) togehter with l_rounded exactly
963
964	REAL(wp) :: dz_stretch_factor_array_2(9) = 1.08_wp !< Array that contains all stretch_factor_2 that belongs to stretch_factor_1
965
966	REAL(wp), PARAMETER :: stretch_factor_interval = 1.0E-06 !< interval for sampling possible stretching factors
967	REAL(wp), PARAMETER :: stretch_factor_lower_limit = 0.88 !< lowest possible stretching factor
968	REAL(wp), PARAMETER :: stretch_factor_upper_limit = 1.12 !< highest possible stretching factor
969
970
971	l = 0
972	DO n = 1, number_end
973
974	iterations = 1
975	stretch_factor_1 = 1.0
976	stretch_factor_2 = 1.0
977	delta_total_old = 1.0
978
979	IF ( dz(n) > dz(n+1) ) THEN
980	DO WHILE ( stretch_factor_1 >= stretch_factor_lower_limit )
981
982	stretch_factor_1 = 1.0 - iterations * stretch_factor_interval
983	distance = ABS( dz_stretch_level_end(n) - &
984	dz_stretch_level_start(n) )
985	numerator = distance*stretch_factor_1/dz(n) + &
986	stretch_factor_1 - distance/dz(n)
987
988	IF ( numerator > 0.0 ) THEN
989	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0
990	l_rounded = NINT( l )
991	delta_l = ABS( l_rounded - l ) / l
992	ENDIF
993
994	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
995
996	delta_stretch_factor = ABS( stretch_factor_1 - &
997	stretch_factor_2 ) / &
998	stretch_factor_2
999
1000	delta_total_new = delta_l + delta_stretch_factor
1001
1002	!
1003	!-- stretch_factor_1 is taken to guarantee that the stretching
1004	!-- procedure ends as close as possible to dz_stretch_level_end.
1005	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
1006	!-- equal to dz(n+1) after l_rounded grid levels.
1007	IF (delta_total_new < delta_total_old) THEN
1008	dz_stretch_factor_array(n) = stretch_factor_1
1009	dz_stretch_factor_array_2(n) = stretch_factor_2
1010	delta_total_old = delta_total_new
1011	ENDIF
1012
1013	iterations = iterations + 1
1014
1015	ENDDO
1016
1017	ELSEIF ( dz(n) < dz(n+1) ) THEN
1018	DO WHILE ( stretch_factor_1 <= stretch_factor_upper_limit )
1019
1020	stretch_factor_1 = 1.0 + iterations * stretch_factor_interval
1021	distance = ABS( dz_stretch_level_end(n) - &
1022	dz_stretch_level_start(n) )
1023	numerator = distance*stretch_factor_1/dz(n) + &
1024	stretch_factor_1 - distance/dz(n)
1025
1026	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0
1027	l_rounded = NINT( l )
1028	delta_l = ABS( l_rounded - l ) / l
1029
1030	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
1031
1032	delta_stretch_factor = ABS( stretch_factor_1 - &
1033	stretch_factor_2 ) / &
1034	stretch_factor_2
1035
1036	delta_total_new = delta_l + delta_stretch_factor
1037
1038	!
1039	!-- stretch_factor_1 is taken to guarantee that the stretching
1040	!-- procedure ends as close as possible to dz_stretch_level_end.
1041	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
1042	!-- equal to dz(n+1) after l_rounded grid levels.
1043	IF (delta_total_new < delta_total_old) THEN
1044	dz_stretch_factor_array(n) = stretch_factor_1
1045	dz_stretch_factor_array_2(n) = stretch_factor_2
1046	delta_total_old = delta_total_new
1047	ENDIF
1048
1049	iterations = iterations + 1
1050	ENDDO
1051
1052	ELSE
1053	message_string= 'Two adjacent values of dz must be different'
1054	CALL message( 'init_grid', 'PA0228', 1, 2, 0, 6, 0 )
1055
1056	ENDIF
1057
1058	!
1059	!-- Check if also the second stretching factor fits into the allowed
1060	!-- interval. If not, print a warning for the user.
1061	IF ( dz_stretch_factor_array_2(n) < stretch_factor_lower_limit .OR. &
1062	dz_stretch_factor_array_2(n) > stretch_factor_upper_limit ) THEN
1063	WRITE( message_string, * ) 'stretch_factor_2 = ', &
1064	dz_stretch_factor_array_2(n), ' which is',&
1065	' responsible for exactly reaching& dz =',&
1066	dz(n+1), 'after a specific amount of', &
1067	' grid levels& exceeds the upper', &
1068	' limit =', stretch_factor_upper_limit, &
1069	' &or lower limit = ', &
1070	stretch_factor_lower_limit
1071	CALL message( 'init_grid', 'PA0499', 0, 1, 0, 6, 0 )
1072
1073	ENDIF
1074	ENDDO
1075
1076	END SUBROUTINE calculate_stretching_factor
1077
1078
1079	! Description:
1080	! -----------------------------------------------------------------------------!
1081	!> Set temporary topography flags and reference buildings on top of underlying
1082	!> orography.
1083	!------------------------------------------------------------------------------!
1084	SUBROUTINE process_topography( topo_3d )
1085
1086	USE arrays_3d, &
1087	ONLY: zu, zw
1088
1089	USE control_parameters, &
1090	ONLY: bc_lr_cyc, bc_ns_cyc, message_string, ocean_mode
1091
1092	USE indices, &
1093	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
1094	nzt
1095
1096	USE netcdf_data_input_mod, &
1097	ONLY: buildings_f, building_id_f, building_type_f, input_pids_static, &
1098	terrain_height_f
1099
1100	USE kinds
1101
1102	USE pegrid
1103
1104	IMPLICIT NONE
1105
1106	INTEGER(iwp) :: i !< running index along x-direction
1107	INTEGER(iwp) :: j !< running index along y-direction
1108	INTEGER(iwp) :: k !< running index along z-direction with respect to numeric grid
1109	INTEGER(iwp) :: k2 !< running index along z-direction with respect to netcdf grid
1110	INTEGER(iwp) :: nr !< index variable indication maximum terrain height for respective building ID
1111	INTEGER(iwp) :: num_build !< counter for number of buildings
1112	INTEGER(iwp) :: topo_top_index !< orography top index, used to map 3D buildings onto terrain
1113
1114	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displace_dum !< displacements of start addresses, used for MPI_ALLGATHERV
1115	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids !< building IDs on entire model domain
1116	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final !< building IDs on entire model domain, multiple occurences are sorted out
1117	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final_tmp !< temporary array used for resizing
1118	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l !< building IDs on local subdomain
1119	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l_tmp !< temporary array used to resize array of building IDs
1120
1121	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings !< number of buildings with different ID on entire model domain
1122	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings_l !< number of buildings with different ID on local subdomain
1123
1124	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< input array for 3D topography and dummy array for setting "outer"-flags
1125
1126	REAL(wp) :: ocean_offset !< offset to consider inverse vertical coordinate at topography definition
1127	REAL(wp) :: oro_min = 0.0_wp !< minimum terrain height in entire model domain, used to reference terrain to zero
1128	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max !< maximum terrain height occupied by an building with certain id
1129	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max_l !< maximum terrain height occupied by an building with certain id, on local subdomain
1130
1131	!
1132	!-- Reference lowest terrain height to zero. In case the minimum terrain height
1133	!-- is non-zero, all grid points of the lower vertical grid levels might be
1134	!-- entirely below the surface, meaning a waste of computational resources.
1135	!-- In order to avoid this, remove the lowest terrain height. Please note,
1136	!-- in case of a nested run, the global minimum from all parent and childs
1137	!-- need to be remove to avoid steep edges at the child-domain boundaries.
1138	IF ( input_pids_static ) THEN
1139
1140	#if defined( __parallel )
1141	CALL MPI_ALLREDUCE( MINVAL( terrain_height_f%var ), oro_min, 1, &
1142	MPI_REAL, MPI_MIN, MPI_COMM_WORLD, ierr )
1143	#else
1144	oro_min = MINVAL( terrain_height_f%var )
1145	#endif
1146	terrain_height_f%var = terrain_height_f%var - oro_min
1147	!
1148	!-- Give an informative message that terrain height is referenced to zero
1149	IF ( oro_min > 0.0_wp ) THEN
1150	WRITE( message_string, * ) 'Terrain height was internally shifted '//&
1151	'downwards by ', oro_min, 'meter(s) to save ' // &
1152	'computational resources.'
1153	CALL message( 'init_grid', 'PA0505', 0, 0, 0, 6, 0 )
1154	ENDIF
1155	ENDIF
1156
1157	!
1158	!-- In the following, buildings and orography are further preprocessed
1159	!-- before they are mapped on the LES grid.
1160	!-- Buildings are mapped on top of the orography by maintaining the roof
1161	!-- shape of the building. This can be achieved by referencing building on
1162	!-- top of the maximum terrain height within the area occupied by the
1163	!-- respective building. As buildings and terrain height are defined PE-wise,
1164	!-- parallelization of this referencing is required (a building can be
1165	!-- distributed between different PEs).
1166	!-- In a first step, determine the number of buildings with different
1167	!-- building id on each PE. In a next step, all building ids are gathered
1168	!-- into one array which is present to all PEs. For each building ID,
1169	!-- the maximum terrain height occupied by the respective building is
1170	!-- computed and distributed to each PE.
1171	!-- Finally, for each building id and its respective reference orography,
1172	!-- builidings are mapped on top.
1173	!--
1174	!-- First, pre-set topography flags, bit 1 indicates orography, bit 2
1175	!-- buildings
1176	!-- classify the respective surfaces.
1177	topo_3d = IBSET( topo_3d, 0 )
1178	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1179	!
1180	!-- In order to map topography on PALM grid also in case of ocean simulations,
1181	!-- pre-calculate an offset value.
1182	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1183	!
1184	!-- Reference buildings on top of orography. This is not necessary
1185	!-- if topography is read from ASCII file as no distinction between buildings
1186	!-- and terrain height can be made. Moreover, this is also not necessary if
1187	!-- urban-surface and land-surface model are used at the same time.
1188	IF ( input_pids_static ) THEN
1189
1190	IF ( buildings_f%from_file ) THEN
1191	num_buildings_l = 0
1192	num_buildings = 0
1193	!
1194	!-- Allocate at least one element for building ids and give it an inital
1195	!-- negative value that will be overwritten later. This, however, is
1196	!-- necessary in case there all IDs in the model domain are fill values.
1197	ALLOCATE( build_ids_l(1) )
1198	build_ids_l = -1
1199	DO i = nxl, nxr
1200	DO j = nys, nyn
1201	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1202	IF ( num_buildings_l(myid) > 0 ) THEN
1203	IF ( ANY( building_id_f%var(j,i) == build_ids_l ) ) &
1204	THEN
1205	CYCLE
1206	ELSE
1207	num_buildings_l(myid) = num_buildings_l(myid) + 1
1208	!
1209	!-- Resize array with different local building ids
1210	ALLOCATE( build_ids_l_tmp(1:SIZE(build_ids_l)) )
1211	build_ids_l_tmp = build_ids_l
1212	DEALLOCATE( build_ids_l )
1213	ALLOCATE( build_ids_l(1:num_buildings_l(myid)) )
1214	build_ids_l(1:num_buildings_l(myid)-1) = &
1215	build_ids_l_tmp(1:num_buildings_l(myid)-1)
1216	build_ids_l(num_buildings_l(myid)) = building_id_f%var(j,i)
1217	DEALLOCATE( build_ids_l_tmp )
1218	ENDIF
1219	!
1220	!-- First occuring building id on PE
1221	ELSE
1222	num_buildings_l(myid) = num_buildings_l(myid) + 1
1223	build_ids_l(1) = building_id_f%var(j,i)
1224	ENDIF
1225	ENDIF
1226	ENDDO
1227	ENDDO
1228	!
1229	!-- Determine number of different building ids for the entire domain
1230	#if defined( __parallel )
1231	CALL MPI_ALLREDUCE( num_buildings_l, num_buildings, numprocs, &
1232	MPI_INTEGER, MPI_SUM, comm2d, ierr )
1233	#else
1234	num_buildings = num_buildings_l
1235	#endif
1236	!
1237	!-- Gather all buildings ids on each PEs.
1238	!-- First, allocate array encompassing all building ids in model domain.
1239	ALLOCATE( build_ids(1:SUM(num_buildings)) )
1240	#if defined( __parallel )
1241	!
1242	!-- Allocate array for displacements.
1243	!-- As each PE may has a different number of buildings, so that
1244	!-- the block sizes send by each PE may not be equal. Hence,
1245	!-- information about the respective displacement is required, indicating
1246	!-- the respective adress where each MPI-task writes into the receive
1247	!-- buffer array
1248	ALLOCATE( displace_dum(0:numprocs-1) )
1249	displace_dum(0) = 0
1250	DO i = 1, numprocs-1
1251	displace_dum(i) = displace_dum(i-1) + num_buildings(i-1)
1252	ENDDO
1253
1254	CALL MPI_ALLGATHERV( build_ids_l(1:num_buildings_l(myid)), &
1255	num_buildings(myid), &
1256	MPI_INTEGER, &
1257	build_ids, &
1258	num_buildings, &
1259	displace_dum, &
1260	MPI_INTEGER, &
1261	comm2d, ierr )
1262
1263	DEALLOCATE( displace_dum )
1264
1265	#else
1266	build_ids = build_ids_l
1267	#endif
1268
1269	!
1270	!-- Note, in parallel mode building ids can occure mutliple times, as
1271	!-- each PE has send its own ids. Therefore, sort out building ids which
1272	!-- appear more than one time.
1273	num_build = 0
1274	DO nr = 1, SIZE(build_ids)
1275
1276	IF ( ALLOCATED(build_ids_final) ) THEN
1277	IF ( ANY( build_ids(nr) == build_ids_final ) ) THEN
1278	CYCLE
1279	ELSE
1280	num_build = num_build + 1
1281	!
1282	!-- Resize
1283	ALLOCATE( build_ids_final_tmp(1:num_build) )
1284	build_ids_final_tmp(1:num_build-1) = build_ids_final(1:num_build-1)
1285	DEALLOCATE( build_ids_final )
1286	ALLOCATE( build_ids_final(1:num_build) )
1287	build_ids_final(1:num_build-1) = build_ids_final_tmp(1:num_build-1)
1288	build_ids_final(num_build) = build_ids(nr)
1289	DEALLOCATE( build_ids_final_tmp )
1290	ENDIF
1291	ELSE
1292	num_build = num_build + 1
1293	ALLOCATE( build_ids_final(1:num_build) )
1294	build_ids_final(num_build) = build_ids(nr)
1295	ENDIF
1296	ENDDO
1297
1298	!
1299	!-- Determine maximumum terrain height occupied by the respective
1300	!-- building and temporalily store on oro_max
1301	ALLOCATE( oro_max_l(1:SIZE(build_ids_final)) )
1302	ALLOCATE( oro_max(1:SIZE(build_ids_final)) )
1303	oro_max_l = 0.0_wp
1304
1305	DO nr = 1, SIZE(build_ids_final)
1306	oro_max_l(nr) = MAXVAL( &
1307	MERGE( terrain_height_f%var(nys:nyn,nxl:nxr), &
1308	0.0_wp, &
1309	building_id_f%var(nys:nyn,nxl:nxr) == &
1310	build_ids_final(nr) ) )
1311	ENDDO
1312
1313	#if defined( __parallel )
1314	IF ( SIZE(build_ids_final) >= 1 ) THEN
1315	CALL MPI_ALLREDUCE( oro_max_l, oro_max, SIZE( oro_max ), MPI_REAL,&
1316	MPI_MAX, comm2d, ierr )
1317	ENDIF
1318	#else
1319	oro_max = oro_max_l
1320	#endif
1321	!
1322	!-- Finally, determine discrete grid height of maximum orography occupied
1323	!-- by a building. Use all-or-nothing approach, i.e. if terrain
1324	!-- exceeds the scalar level the grid box is fully terrain and the
1325	!-- maximum terrain is set to the zw level.
1326	!-- terrain or
1327	oro_max_l = 0.0
1328	DO nr = 1, SIZE(build_ids_final)
1329	DO k = nzb, nzt
1330	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1331	oro_max_l(nr) = zw(k) - ocean_offset
1332	ENDDO
1333	oro_max(nr) = oro_max_l(nr)
1334	ENDDO
1335	ENDIF
1336	!
1337	!-- Allocate array for storing terrain height under buildings
1338	IF ( buildings_f%from_file ) THEN
1339	ALLOCATE( buildings_f%oro_max(nysg:nyng,nxlg:nxrg) )
1340	buildings_f%oro_max = buildings_f%fill1
1341	END IF
1342	!
1343	!-- Map orography as well as buildings onto grid.
1344	DO i = nxl, nxr
1345	DO j = nys, nyn
1346	topo_top_index = 0
1347	!
1348	!-- Obtain index in global building_id array
1349	IF ( buildings_f%from_file ) THEN
1350	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1351	!
1352	!-- Determine index where maximum terrain height occupied by
1353	!-- the respective building height is stored.
1354	nr = MINLOC( ABS( build_ids_final - &
1355	building_id_f%var(j,i) ), DIM = 1 )
1356	!
1357	!-- Save grid-indexed oro_max
1358	buildings_f%oro_max(j,i) = oro_max(nr)
1359	ENDIF
1360	ENDIF
1361	DO k = nzb, nzt
1362	!
1363	!-- In a first step, if grid point is below or equal the given
1364	!-- terrain height, grid point is flagged to be of type natural.
1365	!-- Please note, in case there is also a building which is lower
1366	!-- than the vertical grid spacing, initialization of surface
1367	!-- attributes will not be correct as given surface information
1368	!-- will not be in accordance to the classified grid points.
1369	!-- Hence, in this case, also a building flag.
1370	IF ( zu(k) - ocean_offset <= terrain_height_f%var(j,i) ) THEN
1371	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1372	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1373	topo_top_index = k ! topo_top_index + 1
1374	ENDIF
1375	!
1376	!-- Set building grid points. Here, only consider 2D buildings.
1377	!-- 3D buildings require separate treatment.
1378	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1379	!
1380	!-- Fill-up the terrain to the level of maximum orography
1381	!-- within the building-covered area.
1382	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1383	!
1384	!-- Note, oro_max is always on zw level
1385	IF ( zu(k) - ocean_offset < oro_max(nr) ) THEN
1386	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1387	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1388	ELSEIF ( zu(k) - ocean_offset <= &
1389	oro_max(nr) + buildings_f%var_2d(j,i) ) THEN
1390	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1391	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1392	ENDIF
1393	ENDIF
1394	ENDIF
1395	ENDDO
1396	!
1397	!-- Special treatment for non grid-resolved buildings. This case,
1398	!-- the uppermost terrain grid point is flagged as building as well
1399	!-- well, even though no building exists at all. However, the
1400	!-- surface element will be identified as urban-surface and the
1401	!-- input data provided by the drivers is consistent to the surface
1402	!-- classification. Else, all non grid-resolved buildings would vanish
1403	!-- and identified as terrain grid points, which, however, won't be
1404	!-- consistent with the input data.
1405	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1406	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1407	DO k = nzb, nzt
1408	IF( zw(k) - ocean_offset == oro_max(nr) ) THEN
1409	IF ( buildings_f%var_2d(j,i) <= zu(k+1) - zw(k) ) THEN
1410	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1411	ENDIF
1412	ENDIF
1413	ENDDO
1414	ENDIF
1415	ENDIF
1416	!
1417	!-- Map 3D buildings onto terrain height.
1418	!-- In case of any slopes, map building on top of maximum terrain
1419	!-- height covered by the building. In other words, extend
1420	!-- building down to the respective local terrain-surface height.
1421	IF ( buildings_f%from_file .AND. buildings_f%lod == 2 ) THEN
1422	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1423	!
1424	!-- Extend building down to the terrain surface, i.e. fill-up
1425	!-- surface irregularities below a building. Note, oro_max
1426	!-- is already a discrete height according to the all-or-nothing
1427	!-- approach, i.e. grid box is either topography or atmosphere,
1428	!-- terrain top is defined at upper bound of the grid box.
1429	!-- Hence, check for zw in this case.
1430	!-- Note, do this only for buildings which are surface mounted,
1431	!-- i.e. building types 1-6. Below bridges, which are represented
1432	!-- exclusively by building type 7, terrain shape should be
1433	!-- maintained.
1434	IF ( building_type_f%from_file ) THEN
1435	IF ( building_type_f%var(j,i) /= 7 ) THEN
1436	DO k = topo_top_index + 1, nzt + 1
1437	IF ( zu(k) - ocean_offset <= oro_max(nr) ) THEN
1438	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1439	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1440	ENDIF
1441	ENDDO
1442	!
1443	!-- After surface irregularities are smoothen, determine
1444	!-- lower start index where building starts.
1445	DO k = nzb, nzt
1446	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1447	topo_top_index = k
1448	ENDDO
1449	ENDIF
1450	ENDIF
1451	!
1452	!-- Finally, map building on top.
1453	k2 = 0
1454	DO k = topo_top_index, nzt + 1
1455	IF ( k2 <= buildings_f%nz-1 ) THEN
1456	IF ( buildings_f%var_3d(k2,j,i) == 1 ) THEN
1457	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1458	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1459	ENDIF
1460	ENDIF
1461	k2 = k2 + 1
1462	ENDDO
1463	ENDIF
1464	ENDIF
1465	ENDDO
1466	ENDDO
1467	!
1468	!-- Horizontal exchange the oro_max array, which is required to for
1469	!-- initialization of building-surface properties.
1470	IF ( ALLOCATED( buildings_f%oro_max ) ) THEN
1471	CALL exchange_horiz_2d( buildings_f%oro_max(:,:), nbgp )
1472	ENDIF
1473	!
1474	!-- Deallocate temporary arrays required for processing and reading data
1475	IF ( ALLOCATED( oro_max ) ) DEALLOCATE( oro_max )
1476	IF ( ALLOCATED( oro_max_l ) ) DEALLOCATE( oro_max_l )
1477	IF ( ALLOCATED( build_ids_final ) ) DEALLOCATE( build_ids_final )
1478	!
1479	!-- Topography input via ASCII format.
1480	ELSE
1481	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1482	!
1483	!-- Initialize topography bit 0 (indicates obstacle) everywhere to zero
1484	!-- and clear all grid points at nzb, where alway a surface is defined.
1485	!-- Further, set also bit 1 (indicates terrain) at nzb, which is further
1486	!-- used for masked data output and further processing. Note, in the
1487	!-- ASCII case no distinction is made between buildings and terrain,
1488	!-- so that setting of bit 1 and 2 at the same time has no effect.
1489	topo_3d = IBSET( topo_3d, 0 )
1490	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1491	topo_3d(nzb,:,:) = IBSET( topo_3d(nzb,:,:), 1 )
1492	DO i = nxl, nxr
1493	DO j = nys, nyn
1494	DO k = nzb, nzt
1495	!
1496	!-- Flag topography for all grid points which are below
1497	!-- the local topography height.
1498	!-- Note, each topography is flagged as building.
1499	IF ( zu(k) - ocean_offset <= buildings_f%var_2d(j,i) ) THEN
1500	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1501	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 ) !indicates building
1502	ENDIF
1503	ENDDO
1504	ENDDO
1505	ENDDO
1506	ENDIF
1507
1508	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1509
1510	IF ( .NOT. bc_ns_cyc ) THEN
1511	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1512	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1513	ENDIF
1514
1515	IF ( .NOT. bc_lr_cyc ) THEN
1516	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1517	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1518	ENDIF
1519
1520	END SUBROUTINE process_topography
1521
1522
1523	! Description:
1524	! -----------------------------------------------------------------------------!
1525	!> Filter topography, i.e. fill holes resolved by only one grid point.
1526	!> Such holes are suspected to lead to velocity blow-ups as continuity
1527	!> equation on discrete grid cannot be fulfilled in such case.
1528	!------------------------------------------------------------------------------!
1529	SUBROUTINE filter_topography( topo_3d )
1530
1531	USE control_parameters, &
1532	ONLY: bc_lr_cyc, bc_ns_cyc, message_string
1533
1534	USE indices, &
1535	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt
1536
1537	USE netcdf_data_input_mod, &
1538	ONLY: building_id_f, building_type_f
1539
1540	USE pegrid
1541
1542	IMPLICIT NONE
1543
1544	LOGICAL :: filled = .FALSE. !< flag indicating if holes were filled
1545
1546	INTEGER(iwp) :: i !< running index along x-direction
1547	INTEGER(iwp) :: j !< running index along y-direction
1548	INTEGER(iwp) :: k !< running index along z-direction
1549	INTEGER(iwp) :: num_hole !< number of holes (in topography) resolved by only one grid point
1550	INTEGER(iwp) :: num_hole_l !< number of holes (in topography) resolved by only one grid point on local PE
1551	INTEGER(iwp) :: num_wall !< number of surrounding vertical walls for a single grid point
1552
1553	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo_tmp !< temporary 3D-topography used to fill holes
1554	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< 3D-topography array merging buildings and orography
1555	!
1556	!-- Before checking for holes, set lateral boundary conditions for
1557	!-- topography. After hole-filling, boundary conditions must be set again.
1558	!-- Several iterations are performed, in order to fill holes which might
1559	!-- emerge by the filling-algorithm itself.
1560	ALLOCATE( topo_tmp(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
1561	topo_tmp = 0
1562
1563	num_hole = 99999
1564	DO WHILE ( num_hole > 0 )
1565
1566	num_hole = 0
1567	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1568	!
1569	!-- Exchange also building ID and type. Note, building_type is an one-byte
1570	!-- variable.
1571	IF ( building_id_f%from_file ) &
1572	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1573	IF ( building_type_f%from_file ) &
1574	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1575
1576	topo_tmp = topo_3d
1577	!
1578	!-- In case of non-cyclic lateral boundaries, assume lateral boundary to be
1579	!-- a solid wall. Thus, intermediate spaces of one grid point between
1580	!-- boundary and some topographic structure will be filled.
1581	IF ( .NOT. bc_ns_cyc ) THEN
1582	IF ( nys == 0 ) topo_tmp(:,-1,:) = IBCLR( topo_tmp(:,0,:), 0 )
1583	IF ( nyn == ny ) topo_tmp(:,ny+1,:) = IBCLR( topo_tmp(:,ny,:), 0 )
1584	ENDIF
1585
1586	IF ( .NOT. bc_lr_cyc ) THEN
1587	IF ( nxl == 0 ) topo_tmp(:,:,-1) = IBCLR( topo_tmp(:,:,0), 0 )
1588	IF ( nxr == nx ) topo_tmp(:,:,nx+1) = IBCLR( topo_tmp(:,:,nx), 0 )
1589	ENDIF
1590
1591	num_hole_l = 0
1592	DO i = nxl, nxr
1593	DO j = nys, nyn
1594	DO k = nzb+1, nzt
1595	IF ( BTEST( topo_tmp(k,j,i), 0 ) ) THEN
1596	num_wall = 0
1597	IF ( .NOT. BTEST( topo_tmp(k,j-1,i), 0 ) ) &
1598	num_wall = num_wall + 1
1599	IF ( .NOT. BTEST( topo_tmp(k,j+1,i), 0 ) ) &
1600	num_wall = num_wall + 1
1601	IF ( .NOT. BTEST( topo_tmp(k,j,i-1), 0 ) ) &
1602	num_wall = num_wall + 1
1603	IF ( .NOT. BTEST( topo_tmp(k,j,i+1), 0 ) ) &
1604	num_wall = num_wall + 1
1605	IF ( .NOT. BTEST( topo_tmp(k-1,j,i), 0 ) ) &
1606	num_wall = num_wall + 1
1607	IF ( .NOT. BTEST( topo_tmp(k+1,j,i), 0 ) ) &
1608	num_wall = num_wall + 1
1609
1610	IF ( num_wall >= 4 ) THEN
1611	num_hole_l = num_hole_l + 1
1612	!
1613	!-- Clear flag 0 and set special flag ( bit 4) to indicate
1614	!-- that new topography point is a result of filtering process.
1615	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1616	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 4 )
1617	!
1618	!-- If filled grid point is occupied by a building, classify
1619	!-- it as building grid point.
1620	IF ( building_type_f%from_file ) THEN
1621	IF ( building_type_f%var(j,i) /= &
1622	building_type_f%fill .OR. &
1623	building_type_f%var(j+1,i) /= &
1624	building_type_f%fill .OR. &
1625	building_type_f%var(j-1,i) /= &
1626	building_type_f%fill .OR. &
1627	building_type_f%var(j,i+1) /= &
1628	building_type_f%fill .OR. &
1629	building_type_f%var(j,i-1) /= &
1630	building_type_f%fill ) THEN
1631	!
1632	!-- Set flag indicating building surfaces
1633	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1634	!
1635	!-- Set building_type and ID at this position if not
1636	!-- already set. This is required for proper
1637	!-- initialization of urban-surface energy balance
1638	!-- solver.
1639	IF ( building_type_f%var(j,i) == &
1640	building_type_f%fill ) THEN
1641
1642	IF ( building_type_f%var(j+1,i) /= &
1643	building_type_f%fill ) THEN
1644	building_type_f%var(j,i) = &
1645	building_type_f%var(j+1,i)
1646	building_id_f%var(j,i) = &
1647	building_id_f%var(j+1,i)
1648	ELSEIF ( building_type_f%var(j-1,i) /= &
1649	building_type_f%fill ) THEN
1650	building_type_f%var(j,i) = &
1651	building_type_f%var(j-1,i)
1652	building_id_f%var(j,i) = &
1653	building_id_f%var(j-1,i)
1654	ELSEIF ( building_type_f%var(j,i+1) /= &
1655	building_type_f%fill ) THEN
1656	building_type_f%var(j,i) = &
1657	building_type_f%var(j,i+1)
1658	building_id_f%var(j,i) = &
1659	building_id_f%var(j,i+1)
1660	ELSEIF ( building_type_f%var(j,i-1) /= &
1661	building_type_f%fill ) THEN
1662	building_type_f%var(j,i) = &
1663	building_type_f%var(j,i-1)
1664	building_id_f%var(j,i) = &
1665	building_id_f%var(j,i-1)
1666	ENDIF
1667	ENDIF
1668	ENDIF
1669	ENDIF
1670	!
1671	!-- If filled grid point is already classified as building
1672	!-- everything is fine, else classify this grid point as
1673	!-- natural type grid point. This case, values for the
1674	!-- surface type are already set.
1675	IF ( .NOT. BTEST( topo_3d(k,j,i), 2 ) ) THEN
1676	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1677	ENDIF
1678	ENDIF
1679	ENDIF
1680	ENDDO
1681	ENDDO
1682	ENDDO
1683	!
1684	!-- Count the total number of holes, required for informative message.
1685	#if defined( __parallel )
1686	CALL MPI_ALLREDUCE( num_hole_l, num_hole, 1, MPI_INTEGER, MPI_SUM, &
1687	comm2d, ierr )
1688	#else
1689	num_hole = num_hole_l
1690	#endif
1691	IF ( num_hole > 0 .AND. .NOT. filled ) filled = .TRUE.
1692
1693	ENDDO
1694	!
1695	!-- Create an informative message if any holes were filled.
1696	IF ( filled ) THEN
1697	WRITE( message_string, * ) 'Topography was filtered, i.e. holes ' // &
1698	'resolved by only one grid point ' // &
1699	'were filled during initialization.'
1700	CALL message( 'init_grid', 'PA0430', 0, 0, 0, 6, 0 )
1701	ENDIF
1702
1703	DEALLOCATE( topo_tmp )
1704	!
1705	!-- Finally, exchange topo_3d array again and if necessary set Neumann boundary
1706	!-- condition in case of non-cyclic lateral boundaries.
1707	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1708
1709	IF ( .NOT. bc_ns_cyc ) THEN
1710	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1711	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1712	ENDIF
1713
1714	IF ( .NOT. bc_lr_cyc ) THEN
1715	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1716	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1717	ENDIF
1718	!
1719	!-- Exchange building ID and type. Note, building_type is an one-byte variable.
1720	IF ( building_id_f%from_file ) &
1721	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1722	IF ( building_type_f%from_file ) &
1723	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1724
1725	END SUBROUTINE filter_topography
1726
1727
1728	! Description:
1729	! -----------------------------------------------------------------------------!
1730	!> Reads topography information from file or sets generic topography. Moreover,
1731	!> all topography-relevant topography arrays are initialized, and grid flags
1732	!> are set.
1733	!------------------------------------------------------------------------------!
1734	SUBROUTINE init_topo( topo )
1735
1736	USE arrays_3d, &
1737	ONLY: zw
1738
1739	USE control_parameters, &
1740	ONLY: bc_lr_cyc, bc_ns_cyc, building_height, building_length_x, &
1741	building_length_y, building_wall_left, building_wall_south, &
1742	canyon_height, canyon_wall_left, canyon_wall_south, &
1743	canyon_width_x, canyon_width_y, dp_level_ind_b, dz, &
1744	message_string, topography, topography_grid_convention, &
1745	tunnel_height, tunnel_length, tunnel_width_x, tunnel_width_y, &
1746	tunnel_wall_depth
1747
1748	USE grid_variables, &
1749	ONLY: dx, dy
1750
1751	USE indices, &
1752	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
1753	nzb, nzt
1754
1755	USE kinds
1756
1757	USE netcdf_data_input_mod, &
1758	ONLY: buildings_f, terrain_height_f
1759
1760	USE pegrid
1761
1762	IMPLICIT NONE
1763
1764	INTEGER(iwp) :: bh !< temporary vertical index of building height
1765	INTEGER(iwp) :: blx !< grid point number of building size along x
1766	INTEGER(iwp) :: bly !< grid point number of building size along y
1767	INTEGER(iwp) :: bxl !< index for left building wall
1768	INTEGER(iwp) :: bxr !< index for right building wall
1769	INTEGER(iwp) :: byn !< index for north building wall
1770	INTEGER(iwp) :: bys !< index for south building wall
1771	INTEGER(iwp) :: ch !< temporary vertical index for canyon height
1772	INTEGER(iwp) :: cwx !< grid point number of canyon size along x
1773	INTEGER(iwp) :: cwy !< grid point number of canyon size along y
1774	INTEGER(iwp) :: cxl !< index for left canyon wall
1775	INTEGER(iwp) :: cxr !< index for right canyon wall
1776	INTEGER(iwp) :: cyn !< index for north canyon wall
1777	INTEGER(iwp) :: cys !< index for south canyon wall
1778	INTEGER(iwp) :: i !< index variable along x
1779	INTEGER(iwp) :: j !< index variable along y
1780	INTEGER(iwp) :: k !< index variable along z
1781	INTEGER(iwp) :: hv_in !< heavyside function to model inner tunnel surface
1782	INTEGER(iwp) :: hv_out !< heavyside function to model outer tunnel surface
1783	INTEGER(iwp) :: txe_out !< end position of outer tunnel wall in x
1784	INTEGER(iwp) :: txs_out !< start position of outer tunnel wall in x
1785	INTEGER(iwp) :: tye_out !< end position of outer tunnel wall in y
1786	INTEGER(iwp) :: tys_out !< start position of outer tunnel wall in y
1787	INTEGER(iwp) :: txe_in !< end position of inner tunnel wall in x
1788	INTEGER(iwp) :: txs_in !< start position of inner tunnel wall in x
1789	INTEGER(iwp) :: tye_in !< end position of inner tunnel wall in y
1790	INTEGER(iwp) :: tys_in !< start position of inner tunnel wall in y
1791	INTEGER(iwp) :: td !< tunnel wall depth
1792	INTEGER(iwp) :: th !< height of outer tunnel wall
1793
1794	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
1795	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
1796	!
1797	!-- Check for correct setting of the namelist parameter topography. If
1798	!-- topography information is read from file but topography = 'flat',
1799	!-- initialization does not properly.
1800	IF ( ( buildings_f%from_file .OR. terrain_height_f%from_file ) .AND. &
1801	TRIM( topography ) /= 'read_from_file' ) THEN
1802	message_string = 'If topography information is provided (via ' // &
1803	'Netcdf or ASCII input) topography = ' // &
1804	'"read_from_file" is required.'
1805	CALL message( 'init_grid', 'PA0437', 1, 2, 0, 6, 0 )
1806	ENDIF
1807	!
1808	!-- Set outer and inner index arrays for non-flat topography.
1809	!-- Here consistency checks concerning domain size and periodicity are
1810	!-- necessary.
1811	!-- Within this SELECT CASE structure only nzb_local is initialized
1812	!-- individually depending on the chosen topography type, all other index
1813	!-- arrays are initialized further below.
1814	SELECT CASE ( TRIM( topography ) )
1815
1816	CASE ( 'flat' )
1817	!
1818	!-- Initialilize 3D topography array, used later for initializing flags
1819	topo(nzb+1:nzt+1,:,:) = IBSET( topo(nzb+1:nzt+1,:,:), 0 )
1820
1821	CASE ( 'single_building' )
1822	!
1823	!-- Single rectangular building, by default centered in the middle of the
1824	!-- total domain
1825	blx = NINT( building_length_x / dx )
1826	bly = NINT( building_length_y / dy )
1827	bh = MINLOC( ABS( zw - building_height ), 1 ) - 1
1828	IF ( ABS( zw(bh) - building_height ) == &
1829	ABS( zw(bh+1) - building_height ) ) bh = bh + 1
1830	IF ( building_wall_left == 9999999.9_wp ) THEN
1831	building_wall_left = ( nx + 1 - blx ) / 2 * dx
1832	ENDIF
1833	bxl = NINT( building_wall_left / dx )
1834	bxr = bxl + blx
1835
1836	IF ( building_wall_south == 9999999.9_wp ) THEN
1837	building_wall_south = ( ny + 1 - bly ) / 2 * dy
1838	ENDIF
1839	bys = NINT( building_wall_south / dy )
1840	byn = bys + bly
1841
1842	!
1843	!-- Building size has to meet some requirements
1844	IF ( ( bxl < 1 ) .OR. ( bxr > nx-1 ) .OR. ( bxr < bxl+3 ) .OR. &
1845	( bys < 1 ) .OR. ( byn > ny-1 ) .OR. ( byn < bys+3 ) ) THEN
1846	WRITE( message_string, * ) 'inconsistent building parameters:', &
1847	'&bxl=', bxl, 'bxr=', bxr, 'bys=', bys, &
1848	'byn=', byn, 'nx=', nx, 'ny=', ny
1849	CALL message( 'init_grid', 'PA0203', 1, 2, 0, 6, 0 )
1850	ENDIF
1851
1852	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1853	nzb_local = 0
1854	!
1855	!-- Define the building.
1856	IF ( bxl <= nxr .AND. bxr >= nxl .AND. &
1857	bys <= nyn .AND. byn >= nys ) &
1858	nzb_local(MAX(nys,bys):MIN(nyn,byn),MAX(nxl,bxl):MIN(nxr,bxr)) = bh
1859	!
1860	!-- Set bit array on basis of nzb_local
1861	DO i = nxl, nxr
1862	DO j = nys, nyn
1863	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1864	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1865	ENDDO
1866	ENDDO
1867
1868	DEALLOCATE( nzb_local )
1869
1870	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1871	!
1872	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1873	!-- boundary conditions for topography.
1874	IF ( .NOT. bc_ns_cyc ) THEN
1875	IF ( nys == 0 ) THEN
1876	DO i = 1, nbgp
1877	topo(:,nys-i,:) = topo(:,nys,:)
1878	ENDDO
1879	ENDIF
1880	IF ( nyn == ny ) THEN
1881	DO i = 1, nbgp
1882	topo(:,nyn+i,:) = topo(:,nyn,:)
1883	ENDDO
1884	ENDIF
1885	ENDIF
1886	IF ( .NOT. bc_lr_cyc ) THEN
1887	IF ( nxl == 0 ) THEN
1888	DO i = 1, nbgp
1889	topo(:,:,nxl-i) = topo(:,:,nxl)
1890	ENDDO
1891	ENDIF
1892	IF ( nxr == nx ) THEN
1893	DO i = 1, nbgp
1894	topo(:,:,nxr+i) = topo(:,:,nxr)
1895	ENDDO
1896	ENDIF
1897	ENDIF
1898
1899	CASE ( 'single_street_canyon' )
1900	!
1901	!-- Single quasi-2D street canyon of infinite length in x or y direction.
1902	!-- The canyon is centered in the other direction by default.
1903	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1904	!
1905	!-- Street canyon in y direction
1906	cwx = NINT( canyon_width_x / dx )
1907	IF ( canyon_wall_left == 9999999.9_wp ) THEN
1908	canyon_wall_left = ( nx + 1 - cwx ) / 2 * dx
1909	ENDIF
1910	cxl = NINT( canyon_wall_left / dx )
1911	cxr = cxl + cwx
1912	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1913	!
1914	!-- Street canyon in x direction
1915	cwy = NINT( canyon_width_y / dy )
1916	IF ( canyon_wall_south == 9999999.9_wp ) THEN
1917	canyon_wall_south = ( ny + 1 - cwy ) / 2 * dy
1918	ENDIF
1919	cys = NINT( canyon_wall_south / dy )
1920	cyn = cys + cwy
1921
1922	ELSE
1923
1924	message_string = 'no street canyon width given'
1925	CALL message( 'init_grid', 'PA0204', 1, 2, 0, 6, 0 )
1926
1927	ENDIF
1928
1929	ch = MINLOC( ABS( zw - canyon_height ), 1 ) - 1
1930	IF ( ABS( zw(ch) - canyon_height ) == &
1931	ABS( zw(ch+1) - canyon_height ) ) ch = ch + 1
1932	dp_level_ind_b = ch
1933	!
1934	!-- Street canyon size has to meet some requirements
1935	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1936	IF ( ( cxl < 1 ) .OR. ( cxr > nx-1 ) .OR. ( cwx < 3 ) .OR. &
1937	( ch < 3 ) ) THEN
1938	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1939	'&cxl=', cxl, ' cxr=', cxr, &
1940	' cwx=', cwx, &
1941	' ch=', ch, ' nx=', nx, ' ny=', ny
1942	CALL message( 'init_grid', 'PA0205', 1, 2, 0, 6, 0 )
1943	ENDIF
1944	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1945	IF ( ( cys < 1 ) .OR. ( cyn > ny-1 ) .OR. ( cwy < 3 ) .OR. &
1946	( ch < 3 ) ) THEN
1947	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1948	'&cys=', cys, ' cyn=', cyn, &
1949	' cwy=', cwy, &
1950	' ch=', ch, ' nx=', nx, ' ny=', ny
1951	CALL message( 'init_grid', 'PA0206', 1, 2, 0, 6, 0 )
1952	ENDIF
1953	ENDIF
1954	IF ( canyon_width_x /= 9999999.9_wp .AND. &
1955	canyon_width_y /= 9999999.9_wp ) THEN
1956	message_string = 'inconsistent canyon parameters:' // &
1957	'&street canyon can only be oriented' // &
1958	' either in x- or in y-direction'
1959	CALL message( 'init_grid', 'PA0207', 1, 2, 0, 6, 0 )
1960	ENDIF
1961
1962	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1963	nzb_local = ch
1964	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1965	IF ( cxl <= nxr .AND. cxr >= nxl ) &
1966	nzb_local(:,MAX(nxl,cxl+1):MIN(nxr,cxr-1)) = 0
1967	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1968	IF ( cys <= nyn .AND. cyn >= nys ) &
1969	nzb_local(MAX(nys,cys+1):MIN(nyn,cyn-1),:) = 0
1970	ENDIF
1971	!
1972	!-- Set bit array on basis of nzb_local
1973	DO i = nxl, nxr
1974	DO j = nys, nyn
1975	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1976	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1977	ENDDO
1978	ENDDO
1979	DEALLOCATE( nzb_local )
1980
1981	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1982	!
1983	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1984	!-- boundary conditions for topography.
1985	IF ( .NOT. bc_ns_cyc ) THEN
1986	IF ( nys == 0 ) THEN
1987	DO i = 1, nbgp
1988	topo(:,nys-i,:) = topo(:,nys,:)
1989	ENDDO
1990	ENDIF
1991	IF ( nyn == ny ) THEN
1992	DO i = 1, nbgp
1993	topo(:,nyn+i,:) = topo(:,nyn,:)
1994	ENDDO
1995	ENDIF
1996	ENDIF
1997	IF ( .NOT. bc_lr_cyc ) THEN
1998	IF ( nxl == 0 ) THEN
1999	DO i = 1, nbgp
2000	topo(:,:,nxl-i) = topo(:,:,nxl)
2001	ENDDO
2002	ENDIF
2003	IF ( nxr == nx ) THEN
2004	DO i = 1, nbgp
2005	topo(:,:,nxr+i) = topo(:,:,nxr)
2006	ENDDO
2007	ENDIF
2008	ENDIF
2009
2010	CASE ( 'tunnel' )
2011
2012	!
2013	!-- Tunnel height
2014	IF ( tunnel_height == 9999999.9_wp ) THEN
2015	th = zw( INT( 0.2 * nz) )
2016	ELSE
2017	th = tunnel_height
2018	ENDIF
2019	!
2020	!-- Tunnel-wall depth
2021	IF ( tunnel_wall_depth == 9999999.9_wp ) THEN
2022	td = MAX ( dx, dy, dz(1) )
2023	ELSE
2024	td = tunnel_wall_depth
2025	ENDIF
2026	!
2027	!-- Check for tunnel width
2028	IF ( tunnel_width_x == 9999999.9_wp .AND. &
2029	tunnel_width_y == 9999999.9_wp ) THEN
2030	message_string = 'No tunnel width is given. '
2031	CALL message( 'init_grid', 'PA0280', 1, 2, 0, 6, 0 )
2032	ENDIF
2033	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
2034	tunnel_width_y /= 9999999.9_wp ) THEN
2035	message_string = 'Inconsistent tunnel parameters:' // &
2036	'tunnel can only be oriented' // &
2037	'either in x- or in y-direction.'
2038	CALL message( 'init_grid', 'PA0281', 1, 2, 0, 6, 0 )
2039	ENDIF
2040	!
2041	!-- Tunnel axis along y
2042	IF ( tunnel_width_x /= 9999999.9_wp ) THEN
2043	IF ( tunnel_width_x > ( nx + 1 ) * dx ) THEN
2044	message_string = 'Tunnel width too large'
2045	CALL message( 'init_grid', 'PA0282', 1, 2, 0, 6, 0 )
2046	ENDIF
2047
2048	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_width_x * 0.5_wp )
2049	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_width_x * 0.5_wp )
2050	txs_in = INT( ( nx + 1 ) * 0.5_wp * dx - &
2051	( tunnel_width_x * 0.5_wp - td ) )
2052	txe_in = INT( ( nx + 1 ) * 0.5_wp * dx + &
2053	( tunnel_width_x * 0.5_wp - td ) )
2054
2055	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_length * 0.5_wp )
2056	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_length * 0.5_wp )
2057	tys_in = tys_out
2058	tye_in = tye_out
2059	ENDIF
2060	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
2061	tunnel_width_x - 2.0_wp * td <= 2.0_wp * dx ) &
2062	THEN
2063	message_string = 'Tunnel width too small'
2064	CALL message( 'init_grid', 'PA0175', 1, 2, 0, 6, 0 )
2065	ENDIF
2066	IF ( tunnel_width_y /= 9999999.9_wp .AND. &
2067	tunnel_width_y - 2.0_wp * td <= 2.0_wp * dy ) &
2068	THEN
2069	message_string = 'Tunnel width too small'
2070	CALL message( 'init_grid', 'PA0455', 1, 2, 0, 6, 0 )
2071	ENDIF
2072	!
2073	!-- Tunnel axis along x
2074	IF ( tunnel_width_y /= 9999999.9_wp ) THEN
2075	IF ( tunnel_width_y > ( ny + 1 ) * dy ) THEN
2076	message_string = 'Tunnel width too large'
2077	CALL message( 'init_grid', 'PA0456', 1, 2, 0, 6, 0 )
2078	ENDIF
2079
2080	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_length * 0.5_wp )
2081	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_length * 0.5_wp )
2082	txs_in = txs_out
2083	txe_in = txe_out
2084
2085	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_width_y * 0.5_wp )
2086	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_width_y * 0.5_wp )
2087	tys_in = INT( ( ny + 1 ) * 0.5_wp * dy - &
2088	( tunnel_width_y * 0.5_wp - td ) )
2089	tye_in = INT( ( ny + 1 ) * 0.5_wp * dy + &
2090	( tunnel_width_y * 0.5_wp - td ) )
2091	ENDIF
2092
2093	topo = 0
2094	DO i = nxl, nxr
2095	DO j = nys, nyn
2096	!
2097	!-- Use heaviside function to model outer tunnel surface
2098	hv_out = th * 0.5_wp * &
2099	( ( SIGN( 1.0_wp, i * dx - txs_out ) + 1.0_wp ) &
2100	- ( SIGN( 1.0_wp, i * dx - txe_out ) + 1.0_wp ) )
2101
2102	hv_out = hv_out * 0.5_wp * &
2103	( ( SIGN( 1.0_wp, j * dy - tys_out ) + 1.0_wp ) &
2104	- ( SIGN( 1.0_wp, j * dy - tye_out ) + 1.0_wp ) )
2105	!
2106	!-- Use heaviside function to model inner tunnel surface
2107	hv_in = ( th - td ) * 0.5_wp * &
2108	( ( SIGN( 1.0_wp, i * dx - txs_in ) + 1.0_wp ) &
2109	- ( SIGN( 1.0_wp, i * dx - txe_in ) + 1.0_wp ) )
2110
2111	hv_in = hv_in * 0.5_wp * &
2112	( ( SIGN( 1.0_wp, j * dy - tys_in ) + 1.0_wp ) &
2113	- ( SIGN( 1.0_wp, j * dy - tye_in ) + 1.0_wp ) )
2114	!
2115	!-- Set flags at x-y-positions without any tunnel surface
2116	IF ( hv_out - hv_in == 0.0_wp ) THEN
2117	topo(nzb+1:nzt+1,j,i) = IBSET( topo(nzb+1:nzt+1,j,i), 0 )
2118	!
2119	!-- Set flags at x-y-positions with tunnel surfaces
2120	ELSE
2121	DO k = nzb + 1, nzt + 1
2122	!
2123	!-- Inner tunnel
2124	IF ( hv_out - hv_in == th ) THEN
2125	IF ( zw(k) <= hv_out ) THEN
2126	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
2127	ELSE
2128	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2129	ENDIF
2130	ENDIF
2131	!
2132	!-- Lateral tunnel walls
2133	IF ( hv_out - hv_in == td ) THEN
2134	IF ( zw(k) <= hv_in ) THEN
2135	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2136	ELSEIF ( zw(k) > hv_in .AND. zw(k) <= hv_out ) THEN
2137	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
2138	ELSEIF ( zw(k) > hv_out ) THEN
2139	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2140	ENDIF
2141	ENDIF
2142	ENDDO
2143	ENDIF
2144	ENDDO
2145	ENDDO
2146
2147	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2148	!
2149	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2150	!-- boundary conditions for topography.
2151	IF ( .NOT. bc_ns_cyc ) THEN
2152	IF ( nys == 0 ) THEN
2153	DO i = 1, nbgp
2154	topo(:,nys-i,:) = topo(:,nys,:)
2155	ENDDO
2156	ENDIF
2157	IF ( nyn == ny ) THEN
2158	DO i = 1, nbgp
2159	topo(:,nyn+i,:) = topo(:,nyn,:)
2160	ENDDO
2161	ENDIF
2162	ENDIF
2163	IF ( .NOT. bc_lr_cyc ) THEN
2164	IF ( nxl == 0 ) THEN
2165	DO i = 1, nbgp
2166	topo(:,:,nxl-i) = topo(:,:,nxl)
2167	ENDDO
2168	ENDIF
2169	IF ( nxr == nx ) THEN
2170	DO i = 1, nbgp
2171	topo(:,:,nxr+i) = topo(:,:,nxr)
2172	ENDDO
2173	ENDIF
2174	ENDIF
2175
2176	CASE ( 'read_from_file' )
2177	!
2178	!-- Note, topography information have been already read.
2179	!-- If required, further process topography, i.e. reference buildings on
2180	!-- top of orography and set temporary 3D topography array, which is
2181	!-- used later to set grid flags. Calling of this rouinte is also
2182	!-- required in case of ASCII input, even though no distinction between
2183	!-- terrain- and building height is made in this case.
2184	CALL process_topography( topo )
2185	!
2186	!-- Filter holes resolved by only one grid-point
2187	CALL filter_topography( topo )
2188	!
2189	!-- Exchange ghost-points, as well as add cyclic or Neumann boundary
2190	!-- conditions.
2191	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2192	!
2193	!-- Set lateral boundary conditions for topography on all ghost layers
2194	IF ( .NOT. bc_ns_cyc ) THEN
2195	IF ( nys == 0 ) THEN
2196	DO i = 1, nbgp
2197	topo(:,nys-i,:) = topo(:,nys,:)
2198	ENDDO
2199	ENDIF
2200	IF ( nyn == ny ) THEN
2201	DO i = 1, nbgp
2202	topo(:,nyn+i,:) = topo(:,nyn,:)
2203	ENDDO
2204	ENDIF
2205	ENDIF
2206
2207	IF ( .NOT. bc_lr_cyc ) THEN
2208	IF ( nxl == 0 ) THEN
2209	DO i = 1, nbgp
2210	topo(:,:,nxl-i) = topo(:,:,nxl)
2211	ENDDO
2212	ENDIF
2213	IF ( nxr == nx ) THEN
2214	DO i = 1, nbgp
2215	topo(:,:,nxr+i) = topo(:,:,nxr)
2216	ENDDO
2217	ENDIF
2218	ENDIF
2219
2220
2221	CASE DEFAULT
2222	!
2223	!-- The DEFAULT case is reached either if the parameter topography
2224	!-- contains a wrong character string or if the user has defined a special
2225	!-- case in the user interface. There, the subroutine user_init_grid
2226	!-- checks which of these two conditions applies.
2227	CALL user_init_grid( topo )
2228	CALL filter_topography( topo )
2229
2230	END SELECT
2231	!
2232	!-- Consistency checks and index array initialization are only required for
2233	!-- non-flat topography.
2234	IF ( TRIM( topography ) /= 'flat' ) THEN
2235	!
2236	!-- In case of non-flat topography, check whether the convention how to
2237	!-- define the topography grid has been set correctly, or whether the default
2238	!-- is applicable. If this is not possible, abort.
2239	IF ( TRIM( topography_grid_convention ) == ' ' ) THEN
2240	IF ( TRIM( topography ) /= 'single_building' .AND. &
2241	TRIM( topography ) /= 'single_street_canyon' .AND. &
2242	TRIM( topography ) /= 'tunnel' .AND. &
2243	TRIM( topography ) /= 'read_from_file') THEN
2244	!-- The default value is not applicable here, because it is only valid
2245	!-- for the four standard cases 'single_building',
2246	!-- 'single_street_canyon', 'tunnel' and 'read_from_file'
2247	!-- defined in init_grid.
2248	WRITE( message_string, * ) &
2249	'The value for "topography_grid_convention" ', &
2250	'is not set. Its default value is & only valid for ', &
2251	'"topography" = ''single_building'', ''tunnel'' ', &
2252	'''single_street_canyon'' & or ''read_from_file''.', &
2253	'& Choose ''cell_edge'' or ''cell_center''.'
2254	CALL message( 'init_grid', 'PA0239', 1, 2, 0, 6, 0 )
2255	ELSE
2256	!-- The default value is applicable here.
2257	!-- Set convention according to topography.
2258	IF ( TRIM( topography ) == 'single_building' .OR. &
2259	TRIM( topography ) == 'single_street_canyon' ) THEN
2260	topography_grid_convention = 'cell_edge'
2261	ELSEIF ( TRIM( topography ) == 'read_from_file' .OR. &
2262	TRIM( topography ) == 'tunnel') THEN
2263	topography_grid_convention = 'cell_center'
2264	ENDIF
2265	ENDIF
2266	ELSEIF ( TRIM( topography_grid_convention ) /= 'cell_edge' .AND. &
2267	TRIM( topography_grid_convention ) /= 'cell_center' ) THEN
2268	WRITE( message_string, * ) &
2269	'The value for "topography_grid_convention" is ', &
2270	'not recognized.& Choose ''cell_edge'' or ''cell_center''.'
2271	CALL message( 'init_grid', 'PA0240', 1, 2, 0, 6, 0 )
2272	ENDIF
2273
2274
2275	IF ( topography_grid_convention == 'cell_edge' ) THEN
2276	!
2277	!-- The array nzb_local as defined using the 'cell_edge' convention
2278	!-- describes the actual total size of topography which is defined at the
2279	!-- cell edges where u=0 on the topography walls in x-direction and v=0
2280	!-- on the topography walls in y-direction. However, PALM uses individual
2281	!-- arrays nzb_u\|v\|w\|s_inner\|outer that are based on nzb_s_inner.
2282	!-- Therefore, the extent of topography in nzb_local is now reduced by
2283	!-- 1dx at the E topography walls and by 1dy at the N topography walls
2284	!-- to form the basis for nzb_s_inner.
2285	!-- Note, the reverse memory access (i-j instead of j-i) is absolutely
2286	!-- required at this point.
2287	DO j = nys+1, nyn+1
2288	DO i = nxl-1, nxr
2289	DO k = nzb, nzt+1
2290	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2291	BTEST( topo(k,j,i+1), 0 ) ) &
2292	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2293	ENDDO
2294	ENDDO
2295	ENDDO
2296	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2297
2298	DO i = nxl, nxr+1
2299	DO j = nys-1, nyn
2300	DO k = nzb, nzt+1
2301	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2302	BTEST( topo(k,j+1,i), 0 ) ) &
2303	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2304	ENDDO
2305	ENDDO
2306	ENDDO
2307	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2308
2309	ENDIF
2310	ENDIF
2311
2312
2313	END SUBROUTINE init_topo
2314
2315	SUBROUTINE set_topo_flags(topo)
2316
2317	USE control_parameters, &
2318	ONLY: bc_lr_cyc, bc_ns_cyc, constant_flux_layer, &
2319	scalar_advec, topography, use_surface_fluxes, use_top_fluxes
2320
2321	USE indices, &
2322	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
2323	nzt, topo_top_ind, wall_flags_static_0
2324
2325	USE kinds
2326
2327	IMPLICIT NONE
2328
2329	INTEGER(iwp) :: i !< index variable along x
2330	INTEGER(iwp) :: ibit !< integer bit position of topgraphy masking array
2331	INTEGER(iwp) :: j !< index variable along y
2332	INTEGER(iwp) :: k !< index variable along z
2333
2334	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
2335
2336	ALLOCATE( wall_flags_static_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2337	wall_flags_static_0 = 0
2338	!
2339	!-- Set-up topography flags. First, set flags only for s, u, v and w-grid.
2340	!-- Further special flags will be set in following loops.
2341	DO i = nxl, nxr
2342	DO j = nys, nyn
2343	DO k = nzb, nzt+1
2344	!
2345	!-- scalar grid
2346	IF ( BTEST( topo(k,j,i), 0 ) ) &
2347	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 0 )
2348	!
2349	!-- u grid
2350	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2351	BTEST( topo(k,j,i-1), 0 ) ) &
2352	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 1 )
2353	!
2354	!-- v grid
2355	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2356	BTEST( topo(k,j-1,i), 0 ) ) &
2357	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 2 )
2358
2359	ENDDO
2360
2361	DO k = nzb, nzt
2362	!
2363	!-- w grid
2364	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2365	BTEST( topo(k+1,j,i), 0 ) ) &
2366	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 3 )
2367	ENDDO
2368	wall_flags_static_0(nzt+1,j,i) = IBSET( wall_flags_static_0(nzt+1,j,i), 3 )
2369
2370	ENDDO
2371	ENDDO
2372
2373	CALL exchange_horiz_int( wall_flags_static_0, nys, nyn, nxl, nxr, nzt, nbgp )
2374	!
2375	!-- Set outer array for scalars to mask near-surface grid points. Note, on
2376	!-- basis of flag 24 futher flags will be derived which are used to control
2377	!-- production of subgrid TKE production near walls.
2378	DO i = nxl, nxr
2379	DO j = nys, nyn
2380	DO k = nzb, nzt+1
2381	IF ( BTEST( wall_flags_static_0(k,j-1,i), 0 ) .AND. &
2382	BTEST( wall_flags_static_0(k,j+1,i), 0 ) .AND. &
2383	BTEST( wall_flags_static_0(k,j,i-1), 0 ) .AND. &
2384	BTEST( wall_flags_static_0(k,j,i+1), 0 ) .AND. &
2385	BTEST( wall_flags_static_0(k,j-1,i-1), 0 ) .AND. &
2386	BTEST( wall_flags_static_0(k,j+1,i-1), 0 ) .AND. &
2387	BTEST( wall_flags_static_0(k,j-1,i+1), 0 ) .AND. &
2388	BTEST( wall_flags_static_0(k,j+1,i+1), 0 ) ) &
2389	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 24 )
2390	ENDDO
2391	ENDDO
2392	ENDDO
2393	!
2394	!-- Set further special flags
2395	DO i = nxl, nxr
2396	DO j = nys, nyn
2397	DO k = nzb, nzt+1
2398	!
2399	!-- scalar grid, former nzb_diff_s_inner.
2400	!-- Note, use this flag also to mask topography in diffusion_u and
2401	!-- diffusion_v along the vertical direction. In case of
2402	!-- use_surface_fluxes, fluxes are calculated via MOST, else, simple
2403	!-- gradient approach is applied. Please note, in case of u- and v-
2404	!-- diffuison, a small error is made at edges (on the east side for u,
2405	!-- at the north side for v), since topography on scalar grid point
2406	!-- is used instead of topography on u/v-grid. As number of topography grid
2407	!-- points on uv-grid is different than s-grid, different number of
2408	!-- surface elements would be required. In order to avoid this,
2409	!-- treat edges (u(k,j,i+1)) simply by a gradient approach, i.e. these
2410	!-- points are not masked within diffusion_u. Tests had shown that the
2411	!-- effect on the flow is negligible.
2412	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2413	IF ( BTEST( wall_flags_static_0(k,j,i), 0 ) ) &
2414	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 8 )
2415	ELSE
2416	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 8 )
2417	ENDIF
2418
2419	ENDDO
2420	!
2421	!-- Special flag to control vertical diffusion at model top - former
2422	!-- nzt_diff
2423	wall_flags_static_0(:,j,i) = IBSET( wall_flags_static_0(:,j,i), 9 )
2424	IF ( use_top_fluxes ) &
2425	wall_flags_static_0(nzt+1,j,i) = IBCLR( wall_flags_static_0(nzt+1,j,i), 9 )
2426
2427
2428	DO k = nzb+1, nzt
2429	!
2430	!-- Special flag on u grid, former nzb_u_inner + 1, required
2431	!-- for disturb_field and initialization. Do not disturb directly at
2432	!-- topography, as well as initialize u with zero one grid point outside
2433	!-- of topography.
2434	IF ( BTEST( wall_flags_static_0(k-1,j,i), 1 ) .AND. &
2435	BTEST( wall_flags_static_0(k,j,i), 1 ) .AND. &
2436	BTEST( wall_flags_static_0(k+1,j,i), 1 ) ) &
2437	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 20 )
2438	!
2439	!-- Special flag on v grid, former nzb_v_inner + 1, required
2440	!-- for disturb_field and initialization. Do not disturb directly at
2441	!-- topography, as well as initialize v with zero one grid point outside
2442	!-- of topography.
2443	IF ( BTEST( wall_flags_static_0(k-1,j,i), 2 ) .AND. &
2444	BTEST( wall_flags_static_0(k,j,i), 2 ) .AND. &
2445	BTEST( wall_flags_static_0(k+1,j,i), 2 ) ) &
2446	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 21 )
2447	!
2448	!-- Special flag on scalar grid, former nzb_s_inner+1. Used for
2449	!-- lpm_sgs_tke
2450	IF ( BTEST( wall_flags_static_0(k,j,i), 0 ) .AND. &
2451	BTEST( wall_flags_static_0(k-1,j,i), 0 ) .AND. &
2452	BTEST( wall_flags_static_0(k+1,j,i), 0 ) ) &
2453	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 25 )
2454	!
2455	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2456	!-- in production_e
2457	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2458	IF ( BTEST( wall_flags_static_0(k,j,i), 24 ) .AND. &
2459	BTEST( wall_flags_static_0(k-1,j,i), 24 ) .AND. &
2460	BTEST( wall_flags_static_0(k+1,j,i), 0 ) ) &
2461	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 29 )
2462	ELSE
2463	IF ( BTEST( wall_flags_static_0(k,j,i), 0 ) ) &
2464	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 29 )
2465	ENDIF
2466	!
2467	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2468	!-- in production_e
2469	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2470	IF ( BTEST( wall_flags_static_0(k,j,i), 0 ) .AND. &
2471	BTEST( wall_flags_static_0(k-1,j,i), 0 ) .AND. &
2472	BTEST( wall_flags_static_0(k+1,j,i), 0 ) ) &
2473	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 30 )
2474	ELSE
2475	IF ( BTEST( wall_flags_static_0(k,j,i), 0 ) ) &
2476	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 30 )
2477	ENDIF
2478	ENDDO
2479	!
2480	!-- Flags indicating downward facing walls
2481	DO k = nzb+1, nzt
2482	!
2483	!-- Scalar grid
2484	IF ( BTEST( wall_flags_static_0(k-1,j,i), 0 ) .AND. &
2485	.NOT. BTEST( wall_flags_static_0(k,j,i), 0 ) ) &
2486	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 13 )
2487	!
2488	!-- Downward facing wall on u grid
2489	IF ( BTEST( wall_flags_static_0(k-1,j,i), 1 ) .AND. &
2490	.NOT. BTEST( wall_flags_static_0(k,j,i), 1 ) ) &
2491	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 15 )
2492	!
2493	!-- Downward facing wall on v grid
2494	IF ( BTEST( wall_flags_static_0(k-1,j,i), 2 ) .AND. &
2495	.NOT. BTEST( wall_flags_static_0(k,j,i), 2 ) ) &
2496	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 17 )
2497	!
2498	!-- Downward facing wall on w grid
2499	IF ( BTEST( wall_flags_static_0(k-1,j,i), 3 ) .AND. &
2500	.NOT. BTEST( wall_flags_static_0(k,j,i), 3 ) ) &
2501	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 19 )
2502	ENDDO
2503	!
2504	!-- Flags indicating upward facing walls
2505	DO k = nzb, nzt
2506	!
2507	!-- Upward facing wall on scalar grid
2508	IF ( .NOT. BTEST( wall_flags_static_0(k,j,i), 0 ) .AND. &
2509	BTEST( wall_flags_static_0(k+1,j,i), 0 ) ) &
2510	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 12 )
2511	!
2512	!-- Upward facing wall on u grid
2513	IF ( .NOT. BTEST( wall_flags_static_0(k,j,i), 1 ) .AND. &
2514	BTEST( wall_flags_static_0(k+1,j,i), 1 ) ) &
2515	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 14 )
2516
2517	!
2518	!-- Upward facing wall on v grid
2519	IF ( .NOT. BTEST( wall_flags_static_0(k,j,i), 2 ) .AND. &
2520	BTEST( wall_flags_static_0(k+1,j,i), 2 ) ) &
2521	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 16 )
2522
2523	!
2524	!-- Upward facing wall on w grid
2525	IF ( .NOT. BTEST( wall_flags_static_0(k,j,i), 3 ) .AND. &
2526	BTEST( wall_flags_static_0(k+1,j,i), 3 ) ) &
2527	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 18 )
2528	!
2529	!-- Special flag on scalar grid, former nzb_s_inner
2530	IF ( BTEST( wall_flags_static_0(k,j,i), 0 ) .OR. &
2531	BTEST( wall_flags_static_0(k,j,i), 12 ) .OR. &
2532	BTEST( wall_flags_static_0(k,j,i), 13 ) ) &
2533	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 22 )
2534	!
2535	!-- Special flag on scalar grid, nzb_diff_s_inner - 1, required for
2536	!-- flow_statistics
2537	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2538	IF ( BTEST( wall_flags_static_0(k,j,i), 0 ) .AND. &
2539	BTEST( wall_flags_static_0(k+1,j,i), 0 ) ) &
2540	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 23 )
2541	ELSE
2542	IF ( BTEST( wall_flags_static_0(k,j,i), 22 ) ) &
2543	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 23 )
2544	ENDIF
2545
2546
2547	ENDDO
2548	wall_flags_static_0(nzt+1,j,i) = IBSET( wall_flags_static_0(nzt+1,j,i), 22 )
2549	wall_flags_static_0(nzt+1,j,i) = IBSET( wall_flags_static_0(nzt+1,j,i), 23 )
2550	!
2551	!-- Set flags indicating that topography is close by in horizontal
2552	!-- direction, i.e. flags that infold the topography. These will be used
2553	!-- to set advection flags for passive scalars, where due to large
2554	!-- gradients near buildings stationary numerical oscillations can produce
2555	!-- unrealistically high concentrations. This is only necessary if
2556	!-- WS-scheme is applied for scalar advection. Note, these flags will be
2557	!-- only used for passive scalars such as chemical species or aerosols.
2558	IF ( scalar_advec == 'ws-scheme' ) THEN
2559	DO k = nzb, nzt
2560	IF ( BTEST( wall_flags_static_0(k,j,i), 0 ) .AND. ( &
2561	ANY( .NOT. BTEST( wall_flags_static_0(k,j-3:j+3,i-1), 0 ) ) .OR.&
2562	ANY( .NOT. BTEST( wall_flags_static_0(k,j-3:j+3,i-2), 0 ) ) .OR.&
2563	ANY( .NOT. BTEST( wall_flags_static_0(k,j-3:j+3,i-3), 0 ) ) .OR.&
2564	ANY( .NOT. BTEST( wall_flags_static_0(k,j-3:j+3,i+1), 0 ) ) .OR.&
2565	ANY( .NOT. BTEST( wall_flags_static_0(k,j-3:j+3,i+2), 0 ) ) .OR.&
2566	ANY( .NOT. BTEST( wall_flags_static_0(k,j-3:j+3,i+3), 0 ) ) .OR.&
2567	ANY( .NOT. BTEST( wall_flags_static_0(k,j-1,i-3:i+3), 0 ) ) .OR.&
2568	ANY( .NOT. BTEST( wall_flags_static_0(k,j-2,i-3:i+3), 0 ) ) .OR.&
2569	ANY( .NOT. BTEST( wall_flags_static_0(k,j-3,i-3:i+3), 0 ) ) .OR.&
2570	ANY( .NOT. BTEST( wall_flags_static_0(k,j+1,i-3:i+3), 0 ) ) .OR.&
2571	ANY( .NOT. BTEST( wall_flags_static_0(k,j+2,i-3:i+3), 0 ) ) .OR.&
2572	ANY( .NOT. BTEST( wall_flags_static_0(k,j+3,i-3:i+3), 0 ) ) &
2573	) ) &
2574	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 31 )
2575
2576	ENDDO
2577	ENDIF
2578	ENDDO
2579	ENDDO
2580	!
2581	!-- Finally, set identification flags indicating natural terrain or buildings.
2582	!-- Natural terrain grid points. Information on the type of the surface is
2583	!-- stored in bit 1 of 3D Integer array topo. However, this bit is only set
2584	!-- when topography is read from file. In order to run the land-surface model
2585	!-- also without topography information, set bit 1 explicitely in this case.
2586	!--
2587	!-- Natural terrain grid points
2588	!-- If no topography is initialized, the land-surface is at k = nzb.
2589	IF ( TRIM( topography ) /= 'read_from_file' ) THEN
2590	wall_flags_static_0(nzb,:,:) = IBSET( wall_flags_static_0(nzb,:,:), 5 )
2591	ELSE
2592	DO i = nxl, nxr
2593	DO j = nys, nyn
2594	DO k = nzb, nzt+1
2595	!
2596	!-- Natural terrain grid point
2597	IF ( BTEST( topo(k,j,i), 1 ) ) &
2598	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 5 )
2599	ENDDO
2600	ENDDO
2601	ENDDO
2602	ENDIF
2603	!
2604	!-- Building grid points.
2605	DO i = nxl, nxr
2606	DO j = nys, nyn
2607	DO k = nzb, nzt+1
2608	IF ( BTEST( topo(k,j,i), 2 ) ) &
2609	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 6 )
2610	ENDDO
2611	ENDDO
2612	ENDDO
2613	!
2614	!-- Set flag 4, indicating new topography grid points due to filtering.
2615	DO i = nxl, nxr
2616	DO j = nys, nyn
2617	DO k = nzb, nzt+1
2618	IF ( BTEST( topo(k,j,i), 4 ) ) &
2619	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 4 )
2620	ENDDO
2621	ENDDO
2622	ENDDO
2623	!
2624	!-- Exchange ghost points for wall flags
2625	CALL exchange_horiz_int( wall_flags_static_0, nys, nyn, nxl, nxr, nzt, nbgp )
2626	!
2627	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2628	!-- boundary conditions for topography.
2629	IF ( .NOT. bc_ns_cyc ) THEN
2630	IF ( nys == 0 ) THEN
2631	DO i = 1, nbgp
2632	wall_flags_static_0(:,nys-i,:) = wall_flags_static_0(:,nys,:)
2633	ENDDO
2634	ENDIF
2635	IF ( nyn == ny ) THEN
2636	DO i = 1, nbgp
2637	wall_flags_static_0(:,nyn+i,:) = wall_flags_static_0(:,nyn,:)
2638	ENDDO
2639	ENDIF
2640	ENDIF
2641	IF ( .NOT. bc_lr_cyc ) THEN
2642	IF ( nxl == 0 ) THEN
2643	DO i = 1, nbgp
2644	wall_flags_static_0(:,:,nxl-i) = wall_flags_static_0(:,:,nxl)
2645	ENDDO
2646	ENDIF
2647	IF ( nxr == nx ) THEN
2648	DO i = 1, nbgp
2649	wall_flags_static_0(:,:,nxr+i) = wall_flags_static_0(:,:,nxr)
2650	ENDDO
2651	ENDIF
2652	ENDIF
2653	!
2654	!-- Pre-calculate topography top indices (former get_topography_top_index
2655	!-- function)
2656	ALLOCATE( topo_top_ind(nysg:nyng,nxlg:nxrg,0:4) )
2657	!
2658	!-- Uppermost topography index on scalar grid
2659	ibit = 12
2660	topo_top_ind(:,:,0) = MAXLOC( &
2661	MERGE( 1, 0, &
2662	BTEST( wall_flags_static_0(:,:,:), ibit ) &
2663	), DIM = 1 &
2664	) - 1
2665	!
2666	!-- Uppermost topography index on u grid
2667	ibit = 14
2668	topo_top_ind(:,:,1) = MAXLOC( &
2669	MERGE( 1, 0, &
2670	BTEST( wall_flags_static_0(:,:,:), ibit ) &
2671	), DIM = 1 &
2672	) - 1
2673	!
2674	!-- Uppermost topography index on v grid
2675	ibit = 16
2676	topo_top_ind(:,:,2) = MAXLOC( &
2677	MERGE( 1, 0, &
2678	BTEST( wall_flags_static_0(:,:,:), ibit ) &
2679	), DIM = 1 &
2680	) - 1
2681	!
2682	!-- Uppermost topography index on w grid
2683	ibit = 18
2684	topo_top_ind(:,:,3) = MAXLOC( &
2685	MERGE( 1, 0, &
2686	BTEST( wall_flags_static_0(:,:,:), ibit ) &
2687	), DIM = 1 &
2688	) - 1
2689	!
2690	!-- Uppermost topography index on scalar outer grid
2691	ibit = 24
2692	topo_top_ind(:,:,4) = MAXLOC( &
2693	MERGE( 1, 0, &
2694	BTEST( wall_flags_static_0(:,:,:), ibit ) &
2695	), DIM = 1 &
2696	) - 1
2697
2698	END SUBROUTINE set_topo_flags
2699
2700
2701

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