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source: palm/trunk/SOURCE/init_grid.f90 @ 4427

Last change on this file since 4427 was 4414, checked in by suehring, 5 years ago
Remove deprecated topography arrays; Move basic initialization of numerics into an extra module interface
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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 1997-2020 Leibniz Universitaet Hannover
18	!------------------------------------------------------------------------------!
19	!
20	! Current revisions:
21	! -----------------
22	!
23	!
24	! Former revisions:
25	! -----------------
26	! $Id: init_grid.f90 4414 2020-02-19 20:16:04Z maronga $
27	! - Remove deprecated topography arrays nzb_s_inner, nzb_u_inner, etc.
28	! - Move initialization of boundary conditions and multigrid into an extra
29	! module interface.
30	!
31	! 4386 2020-01-27 15:07:30Z Giersch
32	! Allocation statements, comments, naming of variables revised and _wp added to
33	! real type values
34	!
35	! 4360 2020-01-07 11:25:50Z suehring
36	! Revise error messages for generic tunnel setup.
37	!
38	! 4346 2019-12-18 11:55:56Z motisi
39	! Introduction of wall_flags_total_0, which currently sets bits based on static
40	! topography information used in wall_flags_static_0
41	!
42	! 4340 2019-12-16 08:17:03Z Giersch
43	! Topography closed channel flow with symmetric boundaries implemented
44	!
45	! 4329 2019-12-10 15:46:36Z motisi
46	! Renamed wall_flags_0 to wall_flags_static_0
47	!
48	! 4328 2019-12-09 18:53:04Z suehring
49	! Minor change in nzb_max computation. Commentation added.
50	!
51	! 4314 2019-11-29 10:29:20Z suehring
52	! Set additional topography flag 4 to mark topography grid points emerged
53	! from the filtering process.
54	!
55	! 4294 2019-11-13 18:34:16Z suehring
56	! Bugfix, always set bit 5 and 6 of wall_flags, indicating terrain- and
57	! building surfaces in all cases, in order to enable terrain-following output
58	! also when no land- or urban-surface model is applied.
59	!
60	! 4265 2019-10-15 16:16:24Z suehring
61	! Bugfix for last commit, exchange oro_max variable only when it is allocated
62	! (not necessarily the case when topography is input from ASCII file).
63	!
64	! 4245 2019-09-30 08:40:37Z pavelkrc
65	! Store oro_max (building z-offset) in 2D for building surfaces
66	!
67	! 4189 2019-08-26 16:19:38Z suehring
68	! - Add check for proper setting of namelist parameter topography
69	! - Set flag to indicate land surfaces in case no topography is provided
70	!
71	! 4182 2019-08-22 15:20:23Z scharf
72	! Corrected "Former revisions" section
73	!
74	! 4168 2019-08-16 13:50:17Z suehring
75	! Pre-calculate topography top index and store it on an array (replaces former
76	! functions get_topography_top_index)
77	!
78	! 4159 2019-08-15 13:31:35Z suehring
79	! Revision of topography processing. This was not consistent between 2D and 3D
80	! buildings.
81	!
82	! 4144 2019-08-06 09:11:47Z raasch
83	! relational operators .EQ., .NE., etc. replaced by ==, /=, etc.
84	!
85	! 4115 2019-07-24 12:50:49Z suehring
86	! Bugfix in setting near-surface flag 24, inidicating wall-bounded grid points
87	!
88	! 4110 2019-07-22 17:05:21Z suehring
89	! - Separate initialization of advection flags for momentum and scalars.
90	! - Change subroutine interface for ws_init_flags_scalar to pass boundary flags
91	!
92	! 4109 2019-07-22 17:00:34Z suehring
93	! Fix bad commit
94	!
95	! 3926 2019-04-23 12:56:42Z suehring
96	! Minor bugfix in building mapping when all building IDs in the model domain
97	! are missing
98	!
99	! 3857 2019-04-03 13:00:16Z knoop
100	! In projection of non-building 3D objects onto numerical grid remove
101	! dependency on building_type
102	!
103	! 3763 2019-02-25 17:33:49Z suehring
104	! Replace work-around for ghost point exchange of 1-byte arrays with specific
105	! routine as already done in other routines
106	!
107	! 3761 2019-02-25 15:31:42Z raasch
108	! unused variables removed
109	!
110	! 3661 2019-01-08 18:22:50Z suehring
111	! Remove setting of nzb_max to nzt at non-cyclic boundary PEs, instead,
112	! order degradation of advection scheme is handeled directly in advec_ws
113	!
114	! 3655 2019-01-07 16:51:22Z knoop
115	! Comment added
116	!
117	! Revision 1.1 1997/08/11 06:17:45 raasch
118	! Initial revision (Testversion)
119	!
120	!
121	! Description:
122	! -----------------------------------------------------------------------------!
123	!> Creating grid depending constants
124	!> @todo: Rearrange topo flag list
125	!> @todo: reference 3D buildings on top of orography is not tested and may need
126	!> further improvement for steep slopes
127	!> @todo: Use more advanced setting of building type at filled holes
128	!------------------------------------------------------------------------------!
129	SUBROUTINE init_grid
130
131	USE arrays_3d, &
132	ONLY: dd2zu, ddzu, ddzu_pres, ddzw, dzu, dzw, x, xu, y, yv, zu, zw
133
134	USE control_parameters, &
135	ONLY: constant_flux_layer, dz, dz_max, dz_stretch_factor, &
136	dz_stretch_factor_array, dz_stretch_level, dz_stretch_level_end,&
137	dz_stretch_level_end_index, dz_stretch_level_start_index, &
138	dz_stretch_level_start, ibc_uv_b, message_string, &
139	number_stretch_level_end, &
140	number_stretch_level_start, &
141	ocean_mode, &
142	psolver, &
143	symmetry_flag, &
144	topography, &
145	use_surface_fluxes
146
147	USE grid_variables, &
148	ONLY: ddx, ddx2, ddy, ddy2, dx, dx2, dy, dy2, zu_s_inner, zw_w_inner
149
150	USE indices, &
151	ONLY: nbgp, &
152	nx, &
153	nxl, &
154	nxlg, &
155	nxr, &
156	nxrg, &
157	ny, &
158	nyn, &
159	nyng, &
160	nys, &
161	nysg, &
162	nz, &
163	nzb, &
164	nzb_diff, &
165	nzb_max, &
166	nzt, &
167	topo_top_ind, &
168	topo_min_level
169
170	USE kinds
171
172	USE pegrid
173
174	USE vertical_nesting_mod, &
175	ONLY: vnested, vnest_init_grid
176
177	IMPLICIT NONE
178
179	INTEGER(iwp) :: i !< index variable along x
180	INTEGER(iwp) :: j !< index variable along y
181	INTEGER(iwp) :: k !< index variable along z
182	INTEGER(iwp) :: k_top !< topography top index on local PE
183	INTEGER(iwp) :: n !< loop variable for stretching
184	INTEGER(iwp) :: number_dz !< number of user-specified dz values
185	INTEGER(iwp) :: nzb_local_max !< vertical grid index of maximum topography height
186	INTEGER(iwp) :: nzb_local_min !< vertical grid index of minimum topography height
187
188	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
189
190	REAL(wp) :: dz_level_end !< distance between calculated height level for u/v-grid and user-specified end level for stretching
191	REAL(wp) :: dz_stretched !< stretched vertical grid spacing
192
193	REAL(wp), DIMENSION(:), ALLOCATABLE :: min_dz_stretch_level_end !< Array that contains all minimum heights where the stretching can end
194
195
196	!
197	!-- Calculation of horizontal array bounds including ghost layers
198	nxlg = nxl - nbgp
199	nxrg = nxr + nbgp
200	nysg = nys - nbgp
201	nyng = nyn + nbgp
202
203	!
204	!-- Allocate grid arrays
205	ALLOCATE( x(0:nx) )
206	ALLOCATE( xu(0:nx) )
207
208	DO i = 0, nx
209	xu(i) = i * dx
210	x(i) = i * dx + 0.5_wp * dx
211	ENDDO
212
213	ALLOCATE( y(0:ny) )
214	ALLOCATE( yv(0:ny) )
215
216	DO j = 0, ny
217	yv(j) = j * dy
218	y(j) = j * dy + 0.5_wp * dy
219	ENDDO
220
221	ALLOCATE( ddzu(1:nzt+1) )
222	ALLOCATE( ddzw(1:nzt+1) )
223	ALLOCATE( dd2zu(1:nzt) )
224	ALLOCATE( dzu(1:nzt+1) )
225	ALLOCATE( dzw(1:nzt+1) )
226	ALLOCATE( zu(nzb:nzt+1) )
227	ALLOCATE( zw(nzb:nzt+1) )
228
229	!
230	!-- For constructing an appropriate grid, the vertical grid spacing dz has to
231	!-- be specified with a non-negative value in the parameter file
232	IF ( dz(1) == -1.0_wp ) THEN
233	message_string = 'missing dz'
234	CALL message( 'init_grid', 'PA0200', 1, 2, 0, 6, 0 )
235	ELSEIF ( dz(1) <= 0.0_wp ) THEN
236	WRITE( message_string, * ) 'dz=',dz(1),' <= 0.0'
237	CALL message( 'init_grid', 'PA0201', 1, 2, 0, 6, 0 )
238	ENDIF
239
240	!
241	!-- Initialize dz_stretch_level_start with the value of dz_stretch_level
242	!-- if it was set by the user
243	IF ( dz_stretch_level /= -9999999.9_wp ) THEN
244	dz_stretch_level_start(1) = dz_stretch_level
245	ENDIF
246
247	!
248	!-- Determine number of dz values and stretching levels specified by the
249	!-- user to allow right controlling of the stretching mechanism and to
250	!-- perform error checks. The additional requirement that dz /= dz_max
251	!-- for counting number of user-specified dz values is necessary. Otherwise
252	!-- restarts would abort if the old stretching mechanism with dz_stretch_level
253	!-- is used (Attention: The user is not allowed to specify a dz value equal
254	!-- to the default of dz_max = 999.0).
255	number_dz = COUNT( dz /= -1.0_wp .AND. dz /= dz_max)
256	number_stretch_level_start = COUNT( dz_stretch_level_start /= &
257	-9999999.9_wp )
258	number_stretch_level_end = COUNT( dz_stretch_level_end /= &
259	9999999.9_wp )
260
261	!
262	!-- The number of specified end levels +1 has to be the same as the number
263	!-- of specified dz values
264	IF ( number_dz /= number_stretch_level_end + 1 ) THEN
265	WRITE( message_string, * ) 'The number of values for dz = ', &
266	number_dz, 'has to be the same as& ', &
267	'the number of values for ', &
268	'dz_stretch_level_end + 1 = ', &
269	number_stretch_level_end+1
270	CALL message( 'init_grid', 'PA0156', 1, 2, 0, 6, 0 )
271	ENDIF
272
273	!
274	!-- The number of specified start levels has to be the same or one less than
275	!-- the number of specified dz values
276	IF ( number_dz /= number_stretch_level_start + 1 .AND. &
277	number_dz /= number_stretch_level_start ) THEN
278	WRITE( message_string, * ) 'The number of values for dz = ', &
279	number_dz, 'has to be the same as or one ', &
280	'more than& the number of values for ', &
281	'dz_stretch_level_start = ', &
282	number_stretch_level_start
283	CALL message( 'init_grid', 'PA0211', 1, 2, 0, 6, 0 )
284	ENDIF
285
286	!-- The number of specified start levels has to be the same or one more than
287	!-- the number of specified end levels
288	IF ( number_stretch_level_start /= number_stretch_level_end + 1 .AND. &
289	number_stretch_level_start /= number_stretch_level_end ) THEN
290	WRITE( message_string, * ) 'The number of values for ', &
291	'dz_stretch_level_start = ', &
292	dz_stretch_level_start, 'has to be the ', &
293	'same or one more than& the number of ', &
294	'values for dz_stretch_level_end = ', &
295	number_stretch_level_end
296	CALL message( 'init_grid', 'PA0216', 1, 2, 0, 6, 0 )
297	ENDIF
298
299	!
300	!-- Initialize dz for the free atmosphere with the value of dz_max
301	IF ( dz(number_stretch_level_start+1) == -1.0_wp .AND. &
302	number_stretch_level_start /= 0 ) THEN
303	dz(number_stretch_level_start+1) = dz_max
304	ENDIF
305
306	!
307	!-- Initialize the stretching factor if (infinitely) stretching in the free
308	!-- atmosphere is desired (dz_stretch_level_end was not specified for the
309	!-- free atmosphere)
310	IF ( number_stretch_level_start == number_stretch_level_end + 1 ) THEN
311	dz_stretch_factor_array(number_stretch_level_start) = &
312	dz_stretch_factor
313	ENDIF
314
315	!
316	!-- Allocation of arrays for stretching
317	ALLOCATE( min_dz_stretch_level_end(number_stretch_level_start) )
318
319	!
320	!-- Define the vertical grid levels. Start with atmosphere branch
321	IF ( .NOT. ocean_mode ) THEN
322
323	!
324	!-- The stretching region has to be large enough to allow for a smooth
325	!-- transition between two different grid spacings. The number 4 is an
326	!-- empirical value
327	DO n = 1, number_stretch_level_start
328	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) + &
329	4 * MAX( dz(n),dz(n+1) )
330	ENDDO
331
332	IF ( ANY( min_dz_stretch_level_end(1:number_stretch_level_start) > &
333	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
334	message_string= 'Each dz_stretch_level_end has to be larger ' // &
335	'than its corresponding value for &' // &
336	'dz_stretch_level_start + 4*MAX(dz(n),dz(n+1)) '//&
337	'to allow for smooth grid stretching'
338	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
339	ENDIF
340
341	!
342	!-- Stretching must not be applied within the surface layer
343	!-- (first two grid points). For the default case dz_stretch_level_start
344	!-- is negative. Therefore the absolut value is checked here.
345	IF ( ANY( ABS( dz_stretch_level_start ) <= dz(1) * 1.5_wp ) ) THEN
346	WRITE( message_string, * ) 'Each dz_stretch_level_start has to be ',&
347	'larger than ', dz(1) * 1.5
348	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
349	ENDIF
350
351	!
352	!-- The stretching has to start and end on a grid level. Therefore
353	!-- user-specified values are mapped to the next lowest level. The
354	!-- calculation of the first level is realized differently just because of
355	!-- historical reasons (the advanced/new stretching mechanism was realized
356	!-- in a way that results don't change if the old parameters
357	!-- dz_stretch_level, dz_stretch_factor and dz_max are used)
358	IF ( number_stretch_level_start /= 0 ) THEN
359	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) - &
360	dz(1)/2.0) / dz(1) ) &
361	* dz(1) + dz(1)/2.0
362	ENDIF
363
364	IF ( number_stretch_level_start > 1 ) THEN
365	DO n = 2, number_stretch_level_start
366	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
367	dz(n) ) * dz(n)
368	ENDDO
369	ENDIF
370
371	IF ( number_stretch_level_end /= 0 ) THEN
372	DO n = 1, number_stretch_level_end
373	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
374	dz(n+1) ) * dz(n+1)
375	ENDDO
376	ENDIF
377
378	!
379	!-- Determine stretching factor if necessary
380	IF ( number_stretch_level_end >= 1 ) THEN
381	CALL calculate_stretching_factor( number_stretch_level_end )
382	ENDIF
383
384	!
385	!-- Grid for atmosphere with surface at z=0 (k=0, w-grid).
386	!-- First compute the u- and v-levels. In case of dirichlet bc for u and v
387	!-- the first u/v- and w-level (k=0) are defined at same height (z=0).
388	!-- The second u-level (k=1) corresponds to the top of the
389	!-- surface layer. In case of symmetric boundaries (closed channel flow),
390	!-- the first grid point is always at z=0.
391	IF ( ibc_uv_b == 0 .OR. ibc_uv_b == 2 .OR. &
392	topography == 'closed_channel' ) THEN
393	zu(0) = 0.0_wp
394	ELSE
395	zu(0) = - dz(1) * 0.5_wp
396	ENDIF
397
398	zu(1) = dz(1) * 0.5_wp
399
400	!
401	!-- Determine u and v height levels considering the possibility of grid
402	!-- stretching in several heights.
403	n = 1
404	dz_stretch_level_start_index = nzt+1
405	dz_stretch_level_end_index = nzt+1
406	dz_stretched = dz(1)
407
408	!-- The default value of dz_stretch_level_start is negative, thus the first
409	!-- condition is true even if no stretching shall be applied. Hence, the
410	!-- second condition is also necessary.
411	DO k = 2, nzt+1-symmetry_flag
412	IF ( dz_stretch_level_start(n) <= zu(k-1) .AND. &
413	dz_stretch_level_start(n) /= -9999999.9_wp ) THEN
414	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
415
416	IF ( dz(n) > dz(n+1) ) THEN
417	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
418	ELSE
419	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
420	ENDIF
421
422	IF ( dz_stretch_level_start_index(n) == nzt+1 ) &
423	dz_stretch_level_start_index(n) = k-1
424
425	ENDIF
426
427	zu(k) = zu(k-1) + dz_stretched
428
429	!
430	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
431	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
432
433	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
434	zu(k) = dz_stretch_level_end(n)
435	dz_stretched = dz(n+1)
436	dz_stretch_level_end_index(n) = k
437	n = n + 1
438	ENDIF
439	ENDDO
440
441	!
442	!-- If a closed channel flow is simulated, make sure that grid structure is
443	!-- the same for both bottom and top boundary. (Hint: Using a different dz
444	!-- at the bottom and at the top makes no sense due to symmetric boundaries
445	!-- where dz should be equal. Therefore, different dz at the bottom and top
446	!-- causes an abort (see check_parameters).)
447	IF ( topography == 'closed_channel' ) THEN
448	zu(nzt+1) = zu(nzt) + dz(1) * 0.5_wp
449	ENDIF
450
451	!
452	!-- Compute the w-levels. They are always staggered half-way between the
453	!-- corresponding u-levels. In case of dirichlet bc for u and v at the
454	!-- ground the first u- and w-level (k=0) are defined at same height (z=0).
455	!-- Per default, the top w-level is extrapolated linearly. In case of
456	!-- a closed channel flow, zu(nzt+1) and zw(nzt) must be set explicitely.
457	!-- (Hint: Using a different dz at the bottom and at the top makes no sense
458	!-- due to symmetric boundaries where dz should be equal. Therefore,
459	!-- different dz at the bottom and top causes an abort (see
460	!-- check_parameters).)
461	zw(0) = 0.0_wp
462	DO k = 1, nzt-symmetry_flag
463	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
464	ENDDO
465	IF ( topography == 'closed_channel' ) THEN
466	zw(nzt) = zw(nzt-1) + dz(1)
467	zw(nzt+1) = zw(nzt) + dz(1)
468	ELSE
469	zw(nzt+1) = zw(nzt) + 2.0_wp * ( zu(nzt+1) - zw(nzt) )
470	ENDIF
471
472	ELSE !ocean branch
473
474	!
475	!-- The stretching region has to be large enough to allow for a smooth
476	!-- transition between two different grid spacings. The number 4 is an
477	!-- empirical value
478	DO n = 1, number_stretch_level_start
479	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) - &
480	4 * MAX( dz(n),dz(n+1) )
481	ENDDO
482
483	IF ( ANY( min_dz_stretch_level_end (1:number_stretch_level_start) < &
484	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
485	message_string= 'Each dz_stretch_level_end has to be less ' // &
486	'than its corresponding value for &' // &
487	'dz_stretch_level_start - 4*MAX(dz(n),dz(n+1)) '//&
488	'to allow for smooth grid stretching'
489	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
490	ENDIF
491
492	!
493	!-- Stretching must not be applied close to the surface (last two grid
494	!-- points). For the default case dz_stretch_level_start is negative.
495	IF ( ANY( dz_stretch_level_start >= - dz(1) * 1.5_wp ) ) THEN
496	WRITE( message_string, * ) 'Each dz_stretch_level_start has to be ',&
497	'less than ', -dz(1) * 1.5
498	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
499	ENDIF
500
501	!
502	!-- The stretching has to start and end on a grid level. Therefore
503	!-- user-specified values are mapped to the next highest level. The
504	!-- calculation of the first level is realized differently just because of
505	!-- historical reasons (the advanced/new stretching mechanism was realized
506	!-- in a way that results don't change if the old parameters
507	!-- dz_stretch_level, dz_stretch_factor and dz_max are used)
508	IF ( number_stretch_level_start /= 0 ) THEN
509	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) + &
510	dz(1)/2.0) / dz(1) ) &
511	* dz(1) - dz(1)/2.0
512	ENDIF
513
514	IF ( number_stretch_level_start > 1 ) THEN
515	DO n = 2, number_stretch_level_start
516	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
517	dz(n) ) * dz(n)
518	ENDDO
519	ENDIF
520
521	IF ( number_stretch_level_end /= 0 ) THEN
522	DO n = 1, number_stretch_level_end
523	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
524	dz(n+1) ) * dz(n+1)
525	ENDDO
526	ENDIF
527
528	!
529	!-- Determine stretching factor if necessary
530	IF ( number_stretch_level_end >= 1 ) THEN
531	CALL calculate_stretching_factor( number_stretch_level_end )
532	ENDIF
533
534	!
535	!-- Grid for ocean with free water surface is at k=nzt (w-grid).
536	!-- In case of neumann bc at the ground the first first u-level (k=0) lies
537	!-- below the first w-level (k=0). In case of dirichlet bc the first u- and
538	!-- w-level are defined at same height, but staggered from the second level.
539	!-- The second u-level (k=1) corresponds to the top of the surface layer.
540	!-- z values are negative starting from z=0 (surface)
541	zu(nzt+1) = dz(1) * 0.5_wp
542	zu(nzt) = - dz(1) * 0.5_wp
543
544	!
545	!-- Determine u and v height levels considering the possibility of grid
546	!-- stretching in several heights.
547	n = 1
548	dz_stretch_level_start_index = 0
549	dz_stretch_level_end_index = 0
550	dz_stretched = dz(1)
551
552	DO k = nzt-1, 0, -1
553
554	IF ( dz_stretch_level_start(n) >= zu(k+1) ) THEN
555	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
556
557	IF ( dz(n) > dz(n+1) ) THEN
558	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
559	ELSE
560	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
561	ENDIF
562
563	IF ( dz_stretch_level_start_index(n) == 0 ) &
564	dz_stretch_level_start_index(n) = k+1
565
566	ENDIF
567
568	zu(k) = zu(k+1) - dz_stretched
569
570	!
571	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
572	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
573
574	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
575	zu(k) = dz_stretch_level_end(n)
576	dz_stretched = dz(n+1)
577	dz_stretch_level_end_index(n) = k
578	n = n + 1
579	ENDIF
580	ENDDO
581
582	!
583	!-- Compute the w-levels. They are always staggered half-way between the
584	!-- corresponding u-levels, except in case of dirichlet bc for u and v
585	!-- at the ground. In this case the first u- and w-level are defined at
586	!-- same height. The top w-level (nzt+1) is not used but set for
587	!-- consistency, since w and all scalar variables are defined up tp nzt+1.
588	zw(nzt+1) = dz(1)
589	zw(nzt) = 0.0_wp
590	DO k = 0, nzt
591	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
592	ENDDO
593
594	!
595	!-- In case of dirichlet bc for u and v the first u- and w-level are defined
596	!-- at same height.
597	IF ( ibc_uv_b == 0 ) THEN
598	zu(0) = zw(0)
599	ENDIF
600
601	ENDIF !End of defining the vertical grid levels
602
603	!
604	!-- Compute grid lengths.
605	DO k = 1, nzt+1
606	dzu(k) = zu(k) - zu(k-1)
607	ddzu(k) = 1.0_wp / dzu(k)
608	dzw(k) = zw(k) - zw(k-1)
609	ddzw(k) = 1.0_wp / dzw(k)
610	ENDDO
611
612	DO k = 1, nzt
613	dd2zu(k) = 1.0_wp / ( dzu(k) + dzu(k+1) )
614	ENDDO
615
616	!
617	!-- The FFT- SOR-pressure solvers assume grid spacings of a staggered grid
618	!-- everywhere. For the actual grid, the grid spacing at the lowest level
619	!-- is only dz/2, but should be dz. Therefore, an additional array
620	!-- containing with appropriate grid information is created for these
621	!-- solvers.
622	IF ( psolver(1:9) /= 'multigrid' ) THEN
623	ALLOCATE( ddzu_pres(1:nzt+1) )
624	ddzu_pres = ddzu
625	ddzu_pres(1) = ddzu_pres(2) ! change for lowest level
626	ENDIF
627
628	!
629	!-- Compute the reciprocal values of the horizontal grid lengths.
630	ddx = 1.0_wp / dx
631	ddy = 1.0_wp / dy
632	dx2 = dx * dx
633	dy2 = dy * dy
634	ddx2 = 1.0_wp / dx2
635	ddy2 = 1.0_wp / dy2
636
637	!
638	!-- Allocate 3D array to set topography
639	ALLOCATE( topo(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
640	topo = 0
641	!
642	!-- Initialize topography by generic topography or read topography from file.
643	CALL init_topo( topo )
644	!
645	!-- Set flags to mask topography on the grid.
646	CALL set_topo_flags( topo )
647
648	!
649	!-- Determine the maximum level of topography. It is used for
650	!-- steering the degradation of order of the applied advection scheme,
651	!-- as well in the lpm.
652	k_top = 0
653	DO i = nxl, nxr
654	DO j = nys, nyn
655	DO k = nzb, nzt + 1
656	k_top = MAX( k_top, MERGE( k, 0, .NOT. BTEST( topo(k,j,i), 0 ) ) )
657	ENDDO
658	ENDDO
659	ENDDO
660	#if defined( __parallel )
661	CALL MPI_ALLREDUCE( k_top, nzb_max, 1, MPI_INTEGER, &
662	MPI_MAX, comm2d, ierr )
663	#else
664	nzb_max = k_top
665	#endif
666	!
667	!-- Increment nzb_max by 1 in order to allow for proper diverengence correction.
668	!-- Further, in case topography extents up to the model top, limit to nzt.
669	nzb_max = MIN( nzb_max+1, nzt )
670	!
671	!-- Determine minimum index of topography. Usually, this will be nzb. In case
672	!-- there is elevated topography, however, the lowest topography will be higher.
673	!-- This index is e.g. used to calculate mean first-grid point atmosphere
674	!-- temperature, surface pressure and density, etc. .
675	topo_min_level = 0
676	#if defined( __parallel )
677	CALL MPI_ALLREDUCE( MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
678	topo_min_level, 1, MPI_INTEGER, MPI_MIN, comm2d, ierr )
679	#else
680	topo_min_level = MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
681	#endif
682
683	!
684	!-- Check topography for consistency with model domain. Therefore, use
685	!-- maximum and minium topography-top indices. Note, minimum topography top
686	!-- index is already calculated.
687	IF ( TRIM( topography ) /= 'flat' ) THEN
688	#if defined( __parallel )
689	CALL MPI_ALLREDUCE( MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
690	nzb_local_max, 1, MPI_INTEGER, MPI_MAX, comm2d, ierr )
691	#else
692	nzb_local_max = MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
693	#endif
694	nzb_local_min = topo_min_level
695	!
696	!-- Consistency checks
697	IF ( nzb_local_min < 0 .OR. nzb_local_max > nz + 1 ) THEN
698	WRITE( message_string, * ) 'nzb_local values are outside the', &
699	' model domain', &
700	'&MINVAL( nzb_local ) = ', nzb_local_min, &
701	'&MAXVAL( nzb_local ) = ', nzb_local_max
702	CALL message( 'init_grid', 'PA0210', 1, 2, 0, 6, 0 )
703	ENDIF
704	ENDIF
705	!
706	!-- Define vertical gridpoint from (or to) which on the usual finite difference
707	!-- form (which does not use surface fluxes) is applied
708	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
709	nzb_diff = nzb + 2
710	ELSE
711	nzb_diff = nzb + 1
712	ENDIF
713
714	IF ( TRIM( topography ) /= 'flat' ) THEN
715	!
716	!-- Allocate and set the arrays containing the topography height (for output
717	!-- reasons only).
718	IF ( nxr == nx .AND. nyn /= ny ) THEN
719	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn), &
720	zw_w_inner(nxl:nxr+1,nys:nyn) )
721	ELSEIF ( nxr /= nx .AND. nyn == ny ) THEN
722	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn+1), &
723	zw_w_inner(nxl:nxr,nys:nyn+1) )
724	ELSEIF ( nxr == nx .AND. nyn == ny ) THEN
725	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn+1), &
726	zw_w_inner(nxl:nxr+1,nys:nyn+1) )
727	ELSE
728	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn), &
729	zw_w_inner(nxl:nxr,nys:nyn) )
730	ENDIF
731
732	zu_s_inner = 0.0_wp
733	zw_w_inner = 0.0_wp
734	!
735	!-- Determine local topography height on scalar and w-grid. Note, setting
736	!-- lateral boundary values is not necessary, realized via wall_flags_static_0
737	!-- array. Further, please note that loop bounds are different from
738	!-- nxl to nxr and nys to nyn on south and right model boundary, hence,
739	!-- use intrinsic lbound and ubound functions to infer array bounds.
740	DO i = LBOUND(zu_s_inner, 1), UBOUND(zu_s_inner, 1)
741	DO j = LBOUND(zu_s_inner, 2), UBOUND(zu_s_inner, 2)
742	!
743	!-- Topography height on scalar grid. Therefore, determine index of
744	!-- upward-facing surface element on scalar grid.
745	zu_s_inner(i,j) = zu(topo_top_ind(j,i,0))
746	!
747	!-- Topography height on w grid. Therefore, determine index of
748	!-- upward-facing surface element on w grid.
749	zw_w_inner(i,j) = zw(topo_top_ind(j,i,3))
750	ENDDO
751	ENDDO
752	ENDIF
753	!
754	!-- Vertical nesting: communicate vertical grid level arrays between fine and
755	!-- coarse grid
756	IF ( vnested ) CALL vnest_init_grid
757
758	END SUBROUTINE init_grid
759
760
761	! Description:
762	! -----------------------------------------------------------------------------!
763	!> Calculation of the stretching factor through an iterative method. Ideas were
764	!> taken from the paper "Regional stretched grid generation and its application
765	!> to the NCAR RegCM (1999)". Normally, no analytic solution exists because the
766	!> system of equations has two variables (r,l) but four requirements
767	!> (l=integer, r=[0,88;1,2], Eq(6), Eq(5) starting from index j=1) which
768	!> results into an overdetermined system.
769	!------------------------------------------------------------------------------!
770	SUBROUTINE calculate_stretching_factor( number_end )
771
772	USE control_parameters, &
773	ONLY: dz, dz_stretch_factor_array, &
774	dz_stretch_level_end, dz_stretch_level_start, message_string
775
776	USE kinds
777
778	IMPLICIT NONE
779
780	INTEGER(iwp) :: iterations !< number of iterations until stretch_factor_lower/upper_limit is reached
781	INTEGER(iwp) :: l_rounded !< after l_rounded grid levels dz(n) is strechted to dz(n+1) with stretch_factor_2
782	INTEGER(iwp) :: n !< loop variable for stretching
783
784	INTEGER(iwp), INTENT(IN) :: number_end !< number of user-specified end levels for stretching
785
786	REAL(wp) :: delta_l !< absolute difference between l and l_rounded
787	REAL(wp) :: delta_stretch_factor !< absolute difference between stretch_factor_1 and stretch_factor_2
788	REAL(wp) :: delta_total_new !< sum of delta_l and delta_stretch_factor for the next iteration (should be as small as possible)
789	REAL(wp) :: delta_total_old !< sum of delta_l and delta_stretch_factor for the last iteration
790	REAL(wp) :: distance !< distance between dz_stretch_level_start and dz_stretch_level_end (stretching region)
791	REAL(wp) :: l !< value that fulfil Eq. (5) in the paper mentioned above together with stretch_factor_1 exactly
792	REAL(wp) :: numerator !< numerator of the quotient
793	REAL(wp) :: stretch_factor_1 !< stretching factor that fulfil Eq. (5) togehter with l exactly
794	REAL(wp) :: stretch_factor_2 !< stretching factor that fulfil Eq. (6) togehter with l_rounded exactly
795
796	REAL(wp) :: dz_stretch_factor_array_2(9) = 1.08_wp !< Array that contains all stretch_factor_2 that belongs to stretch_factor_1
797
798	REAL(wp), PARAMETER :: stretch_factor_interval = 1.0E-06_wp !< interval for sampling possible stretching factors
799	REAL(wp), PARAMETER :: stretch_factor_lower_limit = 0.88_wp !< lowest possible stretching factor
800	REAL(wp), PARAMETER :: stretch_factor_upper_limit = 1.12_wp !< highest possible stretching factor
801
802
803	l = 0
804	DO n = 1, number_end
805
806	iterations = 1
807	stretch_factor_1 = 1.0_wp
808	stretch_factor_2 = 1.0_wp
809	delta_total_old = 1.0_wp
810
811	!
812	!-- First branch for stretching from rough to fine
813	IF ( dz(n) > dz(n+1) ) THEN
814	DO WHILE ( stretch_factor_1 >= stretch_factor_lower_limit )
815
816	stretch_factor_1 = 1.0_wp - iterations * stretch_factor_interval
817	distance = ABS( dz_stretch_level_end(n) - &
818	dz_stretch_level_start(n) )
819	numerator = distance*stretch_factor_1/dz(n) + &
820	stretch_factor_1 - distance/dz(n)
821
822	IF ( numerator > 0.0_wp ) THEN
823	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0_wp
824	l_rounded = NINT( l )
825	delta_l = ABS( l_rounded - l ) / l
826	ENDIF
827
828	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
829
830	delta_stretch_factor = ABS( stretch_factor_1 - &
831	stretch_factor_2 ) / &
832	stretch_factor_2
833
834	delta_total_new = delta_l + delta_stretch_factor
835
836	!
837	!-- stretch_factor_1 is taken to guarantee that the stretching
838	!-- procedure ends as close as possible to dz_stretch_level_end.
839	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
840	!-- equal to dz(n+1) after l_rounded grid levels.
841	IF (delta_total_new < delta_total_old) THEN
842	dz_stretch_factor_array(n) = stretch_factor_1
843	dz_stretch_factor_array_2(n) = stretch_factor_2
844	delta_total_old = delta_total_new
845	ENDIF
846
847	iterations = iterations + 1
848
849	ENDDO
850
851	!
852	!-- Second branch for stretching from fine to rough
853	ELSEIF ( dz(n) < dz(n+1) ) THEN
854	DO WHILE ( stretch_factor_1 <= stretch_factor_upper_limit )
855
856	stretch_factor_1 = 1.0_wp + iterations * stretch_factor_interval
857	distance = ABS( dz_stretch_level_end(n) - &
858	dz_stretch_level_start(n) )
859	numerator = distance*stretch_factor_1/dz(n) + &
860	stretch_factor_1 - distance/dz(n)
861
862	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0_wp
863	l_rounded = NINT( l )
864	delta_l = ABS( l_rounded - l ) / l
865
866	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
867
868	delta_stretch_factor = ABS( stretch_factor_1 - &
869	stretch_factor_2 ) / &
870	stretch_factor_2
871
872	delta_total_new = delta_l + delta_stretch_factor
873
874	!
875	!-- stretch_factor_1 is taken to guarantee that the stretching
876	!-- procedure ends as close as possible to dz_stretch_level_end.
877	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
878	!-- equal to dz(n+1) after l_rounded grid levels.
879	IF (delta_total_new < delta_total_old) THEN
880	dz_stretch_factor_array(n) = stretch_factor_1
881	dz_stretch_factor_array_2(n) = stretch_factor_2
882	delta_total_old = delta_total_new
883	ENDIF
884
885	iterations = iterations + 1
886	ENDDO
887
888	ELSE
889	message_string= 'Two adjacent values of dz must be different'
890	CALL message( 'init_grid', 'PA0228', 1, 2, 0, 6, 0 )
891
892	ENDIF
893
894	!
895	!-- Check if also the second stretching factor fits into the allowed
896	!-- interval. If not, print a warning for the user.
897	IF ( dz_stretch_factor_array_2(n) < stretch_factor_lower_limit .OR. &
898	dz_stretch_factor_array_2(n) > stretch_factor_upper_limit ) THEN
899	WRITE( message_string, * ) 'stretch_factor_2 = ', &
900	dz_stretch_factor_array_2(n), ' which is',&
901	' responsible for exactly reaching& dz =',&
902	dz(n+1), 'after a specific amount of', &
903	' grid levels& exceeds the upper', &
904	' limit =', stretch_factor_upper_limit, &
905	' &or lower limit = ', &
906	stretch_factor_lower_limit
907	CALL message( 'init_grid', 'PA0499', 0, 1, 0, 6, 0 )
908
909	ENDIF
910	ENDDO
911
912	END SUBROUTINE calculate_stretching_factor
913
914
915	! Description:
916	! -----------------------------------------------------------------------------!
917	!> Set temporary topography flags and reference buildings on top of underlying
918	!> orography.
919	!------------------------------------------------------------------------------!
920	SUBROUTINE process_topography( topo_3d )
921
922	USE arrays_3d, &
923	ONLY: zu, zw
924
925	USE control_parameters, &
926	ONLY: bc_lr_cyc, bc_ns_cyc, message_string, ocean_mode
927
928	USE indices, &
929	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
930	nzt
931
932	USE netcdf_data_input_mod, &
933	ONLY: buildings_f, building_id_f, building_type_f, input_pids_static, &
934	terrain_height_f
935
936	USE kinds
937
938	USE pegrid
939
940	IMPLICIT NONE
941
942	INTEGER(iwp) :: i !< running index along x-direction
943	INTEGER(iwp) :: j !< running index along y-direction
944	INTEGER(iwp) :: k !< running index along z-direction with respect to numeric grid
945	INTEGER(iwp) :: k2 !< running index along z-direction with respect to netcdf grid
946	INTEGER(iwp) :: nr !< index variable indication maximum terrain height for respective building ID
947	INTEGER(iwp) :: num_build !< counter for number of buildings
948	INTEGER(iwp) :: topo_top_index !< orography top index, used to map 3D buildings onto terrain
949
950	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displace_dum !< displacements of start addresses, used for MPI_ALLGATHERV
951	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids !< building IDs on entire model domain
952	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final !< building IDs on entire model domain, multiple occurences are sorted out
953	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final_tmp !< temporary array used for resizing
954	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l !< building IDs on local subdomain
955	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l_tmp !< temporary array used to resize array of building IDs
956
957	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings !< number of buildings with different ID on entire model domain
958	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings_l !< number of buildings with different ID on local subdomain
959
960	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< input array for 3D topography and dummy array for setting "outer"-flags
961
962	REAL(wp) :: ocean_offset !< offset to consider inverse vertical coordinate at topography definition
963	REAL(wp) :: oro_min = 0.0_wp !< minimum terrain height in entire model domain, used to reference terrain to zero
964	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max !< maximum terrain height occupied by an building with certain id
965	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max_l !< maximum terrain height occupied by an building with certain id, on local subdomain
966
967	!
968	!-- Reference lowest terrain height to zero. In case the minimum terrain height
969	!-- is non-zero, all grid points of the lower vertical grid levels might be
970	!-- entirely below the surface, meaning a waste of computational resources.
971	!-- In order to avoid this, remove the lowest terrain height. Please note,
972	!-- in case of a nested run, the global minimum from all parent and childs
973	!-- need to be remove to avoid steep edges at the child-domain boundaries.
974	IF ( input_pids_static ) THEN
975
976	#if defined( __parallel )
977	CALL MPI_ALLREDUCE( MINVAL( terrain_height_f%var ), oro_min, 1, &
978	MPI_REAL, MPI_MIN, MPI_COMM_WORLD, ierr )
979	#else
980	oro_min = MINVAL( terrain_height_f%var )
981	#endif
982	terrain_height_f%var = terrain_height_f%var - oro_min
983	!
984	!-- Give an informative message that terrain height is referenced to zero
985	IF ( oro_min > 0.0_wp ) THEN
986	WRITE( message_string, * ) 'Terrain height was internally shifted '//&
987	'downwards by ', oro_min, 'meter(s) to save ' // &
988	'computational resources.'
989	CALL message( 'init_grid', 'PA0505', 0, 0, 0, 6, 0 )
990	ENDIF
991	ENDIF
992
993	!
994	!-- In the following, buildings and orography are further preprocessed
995	!-- before they are mapped on the LES grid.
996	!-- Buildings are mapped on top of the orography by maintaining the roof
997	!-- shape of the building. This can be achieved by referencing building on
998	!-- top of the maximum terrain height within the area occupied by the
999	!-- respective building. As buildings and terrain height are defined PE-wise,
1000	!-- parallelization of this referencing is required (a building can be
1001	!-- distributed between different PEs).
1002	!-- In a first step, determine the number of buildings with different
1003	!-- building id on each PE. In a next step, all building ids are gathered
1004	!-- into one array which is present to all PEs. For each building ID,
1005	!-- the maximum terrain height occupied by the respective building is
1006	!-- computed and distributed to each PE.
1007	!-- Finally, for each building id and its respective reference orography,
1008	!-- builidings are mapped on top.
1009	!--
1010	!-- First, pre-set topography flags, bit 1 indicates orography, bit 2
1011	!-- buildings
1012	!-- classify the respective surfaces.
1013	topo_3d = IBSET( topo_3d, 0 )
1014	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1015	!
1016	!-- In order to map topography on PALM grid also in case of ocean simulations,
1017	!-- pre-calculate an offset value.
1018	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1019	!
1020	!-- Reference buildings on top of orography. This is not necessary
1021	!-- if topography is read from ASCII file as no distinction between buildings
1022	!-- and terrain height can be made. Moreover, this is also not necessary if
1023	!-- urban-surface and land-surface model are used at the same time.
1024	IF ( input_pids_static ) THEN
1025
1026	IF ( buildings_f%from_file ) THEN
1027	num_buildings_l = 0
1028	num_buildings = 0
1029	!
1030	!-- Allocate at least one element for building ids and give it an inital
1031	!-- negative value that will be overwritten later. This, however, is
1032	!-- necessary in case there all IDs in the model domain are fill values.
1033	ALLOCATE( build_ids_l(1) )
1034	build_ids_l = -1
1035	DO i = nxl, nxr
1036	DO j = nys, nyn
1037	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1038	IF ( num_buildings_l(myid) > 0 ) THEN
1039	IF ( ANY( building_id_f%var(j,i) == build_ids_l ) ) &
1040	THEN
1041	CYCLE
1042	ELSE
1043	num_buildings_l(myid) = num_buildings_l(myid) + 1
1044	!
1045	!-- Resize array with different local building ids
1046	ALLOCATE( build_ids_l_tmp(1:SIZE(build_ids_l)) )
1047	build_ids_l_tmp = build_ids_l
1048	DEALLOCATE( build_ids_l )
1049	ALLOCATE( build_ids_l(1:num_buildings_l(myid)) )
1050	build_ids_l(1:num_buildings_l(myid)-1) = &
1051	build_ids_l_tmp(1:num_buildings_l(myid)-1)
1052	build_ids_l(num_buildings_l(myid)) = building_id_f%var(j,i)
1053	DEALLOCATE( build_ids_l_tmp )
1054	ENDIF
1055	!
1056	!-- First occuring building id on PE
1057	ELSE
1058	num_buildings_l(myid) = num_buildings_l(myid) + 1
1059	build_ids_l(1) = building_id_f%var(j,i)
1060	ENDIF
1061	ENDIF
1062	ENDDO
1063	ENDDO
1064	!
1065	!-- Determine number of different building ids for the entire domain
1066	#if defined( __parallel )
1067	CALL MPI_ALLREDUCE( num_buildings_l, num_buildings, numprocs, &
1068	MPI_INTEGER, MPI_SUM, comm2d, ierr )
1069	#else
1070	num_buildings = num_buildings_l
1071	#endif
1072	!
1073	!-- Gather all buildings ids on each PEs.
1074	!-- First, allocate array encompassing all building ids in model domain.
1075	ALLOCATE( build_ids(1:SUM(num_buildings)) )
1076	#if defined( __parallel )
1077	!
1078	!-- Allocate array for displacements.
1079	!-- As each PE may has a different number of buildings, so that
1080	!-- the block sizes send by each PE may not be equal. Hence,
1081	!-- information about the respective displacement is required, indicating
1082	!-- the respective adress where each MPI-task writes into the receive
1083	!-- buffer array
1084	ALLOCATE( displace_dum(0:numprocs-1) )
1085	displace_dum(0) = 0
1086	DO i = 1, numprocs-1
1087	displace_dum(i) = displace_dum(i-1) + num_buildings(i-1)
1088	ENDDO
1089
1090	CALL MPI_ALLGATHERV( build_ids_l(1:num_buildings_l(myid)), &
1091	num_buildings(myid), &
1092	MPI_INTEGER, &
1093	build_ids, &
1094	num_buildings, &
1095	displace_dum, &
1096	MPI_INTEGER, &
1097	comm2d, ierr )
1098
1099	DEALLOCATE( displace_dum )
1100
1101	#else
1102	build_ids = build_ids_l
1103	#endif
1104
1105	!
1106	!-- Note, in parallel mode building ids can occure mutliple times, as
1107	!-- each PE has send its own ids. Therefore, sort out building ids which
1108	!-- appear more than one time.
1109	num_build = 0
1110	DO nr = 1, SIZE(build_ids)
1111
1112	IF ( ALLOCATED(build_ids_final) ) THEN
1113	IF ( ANY( build_ids(nr) == build_ids_final ) ) THEN
1114	CYCLE
1115	ELSE
1116	num_build = num_build + 1
1117	!
1118	!-- Resize
1119	ALLOCATE( build_ids_final_tmp(1:num_build) )
1120	build_ids_final_tmp(1:num_build-1) = build_ids_final(1:num_build-1)
1121	DEALLOCATE( build_ids_final )
1122	ALLOCATE( build_ids_final(1:num_build) )
1123	build_ids_final(1:num_build-1) = build_ids_final_tmp(1:num_build-1)
1124	build_ids_final(num_build) = build_ids(nr)
1125	DEALLOCATE( build_ids_final_tmp )
1126	ENDIF
1127	ELSE
1128	num_build = num_build + 1
1129	ALLOCATE( build_ids_final(1:num_build) )
1130	build_ids_final(num_build) = build_ids(nr)
1131	ENDIF
1132	ENDDO
1133
1134	!
1135	!-- Determine maximumum terrain height occupied by the respective
1136	!-- building and temporalily store on oro_max
1137	ALLOCATE( oro_max_l(1:SIZE(build_ids_final)) )
1138	ALLOCATE( oro_max(1:SIZE(build_ids_final)) )
1139	oro_max_l = 0.0_wp
1140
1141	DO nr = 1, SIZE(build_ids_final)
1142	oro_max_l(nr) = MAXVAL( &
1143	MERGE( terrain_height_f%var(nys:nyn,nxl:nxr), &
1144	0.0_wp, &
1145	building_id_f%var(nys:nyn,nxl:nxr) == &
1146	build_ids_final(nr) ) )
1147	ENDDO
1148
1149	#if defined( __parallel )
1150	IF ( SIZE(build_ids_final) >= 1 ) THEN
1151	CALL MPI_ALLREDUCE( oro_max_l, oro_max, SIZE( oro_max ), MPI_REAL,&
1152	MPI_MAX, comm2d, ierr )
1153	ENDIF
1154	#else
1155	oro_max = oro_max_l
1156	#endif
1157	!
1158	!-- Finally, determine discrete grid height of maximum orography occupied
1159	!-- by a building. Use all-or-nothing approach, i.e. if terrain
1160	!-- exceeds the scalar level the grid box is fully terrain and the
1161	!-- maximum terrain is set to the zw level.
1162	!-- terrain or
1163	oro_max_l = 0.0
1164	DO nr = 1, SIZE(build_ids_final)
1165	DO k = nzb, nzt
1166	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1167	oro_max_l(nr) = zw(k) - ocean_offset
1168	ENDDO
1169	oro_max(nr) = oro_max_l(nr)
1170	ENDDO
1171	ENDIF
1172	!
1173	!-- Allocate array for storing terrain height under buildings
1174	IF ( buildings_f%from_file ) THEN
1175	ALLOCATE( buildings_f%oro_max(nysg:nyng,nxlg:nxrg) )
1176	buildings_f%oro_max = buildings_f%fill1
1177	END IF
1178	!
1179	!-- Map orography as well as buildings onto grid.
1180	DO i = nxl, nxr
1181	DO j = nys, nyn
1182	topo_top_index = 0
1183	!
1184	!-- Obtain index in global building_id array
1185	IF ( buildings_f%from_file ) THEN
1186	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1187	!
1188	!-- Determine index where maximum terrain height occupied by
1189	!-- the respective building height is stored.
1190	nr = MINLOC( ABS( build_ids_final - &
1191	building_id_f%var(j,i) ), DIM = 1 )
1192	!
1193	!-- Save grid-indexed oro_max
1194	buildings_f%oro_max(j,i) = oro_max(nr)
1195	ENDIF
1196	ENDIF
1197	DO k = nzb, nzt
1198	!
1199	!-- In a first step, if grid point is below or equal the given
1200	!-- terrain height, grid point is flagged to be of type natural.
1201	!-- Please note, in case there is also a building which is lower
1202	!-- than the vertical grid spacing, initialization of surface
1203	!-- attributes will not be correct as given surface information
1204	!-- will not be in accordance to the classified grid points.
1205	!-- Hence, in this case, also a building flag.
1206	IF ( zu(k) - ocean_offset <= terrain_height_f%var(j,i) ) THEN
1207	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1208	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1209	topo_top_index = k ! topo_top_index + 1
1210	ENDIF
1211	!
1212	!-- Set building grid points. Here, only consider 2D buildings.
1213	!-- 3D buildings require separate treatment.
1214	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1215	!
1216	!-- Fill-up the terrain to the level of maximum orography
1217	!-- within the building-covered area.
1218	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1219	!
1220	!-- Note, oro_max is always on zw level
1221	IF ( zu(k) - ocean_offset < oro_max(nr) ) THEN
1222	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1223	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1224	ELSEIF ( zu(k) - ocean_offset <= &
1225	oro_max(nr) + buildings_f%var_2d(j,i) ) THEN
1226	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1227	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1228	ENDIF
1229	ENDIF
1230	ENDIF
1231	ENDDO
1232	!
1233	!-- Special treatment for non grid-resolved buildings. This case,
1234	!-- the uppermost terrain grid point is flagged as building as well
1235	!-- well, even though no building exists at all. However, the
1236	!-- surface element will be identified as urban-surface and the
1237	!-- input data provided by the drivers is consistent to the surface
1238	!-- classification. Else, all non grid-resolved buildings would vanish
1239	!-- and identified as terrain grid points, which, however, won't be
1240	!-- consistent with the input data.
1241	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1242	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1243	DO k = nzb, nzt
1244	IF( zw(k) - ocean_offset == oro_max(nr) ) THEN
1245	IF ( buildings_f%var_2d(j,i) <= zu(k+1) - zw(k) ) THEN
1246	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1247	ENDIF
1248	ENDIF
1249	ENDDO
1250	ENDIF
1251	ENDIF
1252	!
1253	!-- Map 3D buildings onto terrain height.
1254	!-- In case of any slopes, map building on top of maximum terrain
1255	!-- height covered by the building. In other words, extend
1256	!-- building down to the respective local terrain-surface height.
1257	IF ( buildings_f%from_file .AND. buildings_f%lod == 2 ) THEN
1258	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1259	!
1260	!-- Extend building down to the terrain surface, i.e. fill-up
1261	!-- surface irregularities below a building. Note, oro_max
1262	!-- is already a discrete height according to the all-or-nothing
1263	!-- approach, i.e. grid box is either topography or atmosphere,
1264	!-- terrain top is defined at upper bound of the grid box.
1265	!-- Hence, check for zw in this case.
1266	!-- Note, do this only for buildings which are surface mounted,
1267	!-- i.e. building types 1-6. Below bridges, which are represented
1268	!-- exclusively by building type 7, terrain shape should be
1269	!-- maintained.
1270	IF ( building_type_f%from_file ) THEN
1271	IF ( building_type_f%var(j,i) /= 7 ) THEN
1272	DO k = topo_top_index + 1, nzt + 1
1273	IF ( zu(k) - ocean_offset <= oro_max(nr) ) THEN
1274	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1275	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1276	ENDIF
1277	ENDDO
1278	!
1279	!-- After surface irregularities are smoothen, determine
1280	!-- lower start index where building starts.
1281	DO k = nzb, nzt
1282	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1283	topo_top_index = k
1284	ENDDO
1285	ENDIF
1286	ENDIF
1287	!
1288	!-- Finally, map building on top.
1289	k2 = 0
1290	DO k = topo_top_index, nzt + 1
1291	IF ( k2 <= buildings_f%nz-1 ) THEN
1292	IF ( buildings_f%var_3d(k2,j,i) == 1 ) THEN
1293	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1294	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1295	ENDIF
1296	ENDIF
1297	k2 = k2 + 1
1298	ENDDO
1299	ENDIF
1300	ENDIF
1301	ENDDO
1302	ENDDO
1303	!
1304	!-- Horizontal exchange the oro_max array, which is required to for
1305	!-- initialization of building-surface properties.
1306	IF ( ALLOCATED( buildings_f%oro_max ) ) THEN
1307	CALL exchange_horiz_2d( buildings_f%oro_max(:,:), nbgp )
1308	ENDIF
1309	!
1310	!-- Deallocate temporary arrays required for processing and reading data
1311	IF ( ALLOCATED( oro_max ) ) DEALLOCATE( oro_max )
1312	IF ( ALLOCATED( oro_max_l ) ) DEALLOCATE( oro_max_l )
1313	IF ( ALLOCATED( build_ids_final ) ) DEALLOCATE( build_ids_final )
1314	!
1315	!-- Topography input via ASCII format.
1316	ELSE
1317	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1318	!
1319	!-- Initialize topography bit 0 (indicates obstacle) everywhere to zero
1320	!-- and clear all grid points at nzb, where alway a surface is defined.
1321	!-- Further, set also bit 1 (indicates terrain) at nzb, which is further
1322	!-- used for masked data output and further processing. Note, in the
1323	!-- ASCII case no distinction is made between buildings and terrain,
1324	!-- so that setting of bit 1 and 2 at the same time has no effect.
1325	topo_3d = IBSET( topo_3d, 0 )
1326	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1327	topo_3d(nzb,:,:) = IBSET( topo_3d(nzb,:,:), 1 )
1328	DO i = nxl, nxr
1329	DO j = nys, nyn
1330	DO k = nzb, nzt
1331	!
1332	!-- Flag topography for all grid points which are below
1333	!-- the local topography height.
1334	!-- Note, each topography is flagged as building.
1335	IF ( zu(k) - ocean_offset <= buildings_f%var_2d(j,i) ) THEN
1336	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1337	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 ) !indicates building
1338	ENDIF
1339	ENDDO
1340	ENDDO
1341	ENDDO
1342	ENDIF
1343
1344	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1345
1346	IF ( .NOT. bc_ns_cyc ) THEN
1347	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1348	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1349	ENDIF
1350
1351	IF ( .NOT. bc_lr_cyc ) THEN
1352	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1353	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1354	ENDIF
1355
1356	END SUBROUTINE process_topography
1357
1358
1359	! Description:
1360	! -----------------------------------------------------------------------------!
1361	!> Filter topography, i.e. fill holes resolved by only one grid point.
1362	!> Such holes are suspected to lead to velocity blow-ups as continuity
1363	!> equation on discrete grid cannot be fulfilled in such case.
1364	!------------------------------------------------------------------------------!
1365	SUBROUTINE filter_topography( topo_3d )
1366
1367	USE control_parameters, &
1368	ONLY: bc_lr_cyc, bc_ns_cyc, message_string
1369
1370	USE indices, &
1371	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt
1372
1373	USE netcdf_data_input_mod, &
1374	ONLY: building_id_f, building_type_f
1375
1376	USE pegrid
1377
1378	IMPLICIT NONE
1379
1380	LOGICAL :: filled = .FALSE. !< flag indicating if holes were filled
1381
1382	INTEGER(iwp) :: i !< running index along x-direction
1383	INTEGER(iwp) :: j !< running index along y-direction
1384	INTEGER(iwp) :: k !< running index along z-direction
1385	INTEGER(iwp) :: num_hole !< number of holes (in topography) resolved by only one grid point
1386	INTEGER(iwp) :: num_hole_l !< number of holes (in topography) resolved by only one grid point on local PE
1387	INTEGER(iwp) :: num_wall !< number of surrounding vertical walls for a single grid point
1388
1389	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo_tmp !< temporary 3D-topography used to fill holes
1390	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< 3D-topography array merging buildings and orography
1391	!
1392	!-- Before checking for holes, set lateral boundary conditions for
1393	!-- topography. After hole-filling, boundary conditions must be set again.
1394	!-- Several iterations are performed, in order to fill holes which might
1395	!-- emerge by the filling-algorithm itself.
1396	ALLOCATE( topo_tmp(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
1397	topo_tmp = 0
1398
1399	num_hole = 99999
1400	DO WHILE ( num_hole > 0 )
1401
1402	num_hole = 0
1403	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1404	!
1405	!-- Exchange also building ID and type. Note, building_type is an one-byte
1406	!-- variable.
1407	IF ( building_id_f%from_file ) &
1408	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1409	IF ( building_type_f%from_file ) &
1410	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1411
1412	topo_tmp = topo_3d
1413	!
1414	!-- In case of non-cyclic lateral boundaries, assume lateral boundary to be
1415	!-- a solid wall. Thus, intermediate spaces of one grid point between
1416	!-- boundary and some topographic structure will be filled.
1417	IF ( .NOT. bc_ns_cyc ) THEN
1418	IF ( nys == 0 ) topo_tmp(:,-1,:) = IBCLR( topo_tmp(:,0,:), 0 )
1419	IF ( nyn == ny ) topo_tmp(:,ny+1,:) = IBCLR( topo_tmp(:,ny,:), 0 )
1420	ENDIF
1421
1422	IF ( .NOT. bc_lr_cyc ) THEN
1423	IF ( nxl == 0 ) topo_tmp(:,:,-1) = IBCLR( topo_tmp(:,:,0), 0 )
1424	IF ( nxr == nx ) topo_tmp(:,:,nx+1) = IBCLR( topo_tmp(:,:,nx), 0 )
1425	ENDIF
1426
1427	num_hole_l = 0
1428	DO i = nxl, nxr
1429	DO j = nys, nyn
1430	DO k = nzb+1, nzt
1431	IF ( BTEST( topo_tmp(k,j,i), 0 ) ) THEN
1432	num_wall = 0
1433	IF ( .NOT. BTEST( topo_tmp(k,j-1,i), 0 ) ) &
1434	num_wall = num_wall + 1
1435	IF ( .NOT. BTEST( topo_tmp(k,j+1,i), 0 ) ) &
1436	num_wall = num_wall + 1
1437	IF ( .NOT. BTEST( topo_tmp(k,j,i-1), 0 ) ) &
1438	num_wall = num_wall + 1
1439	IF ( .NOT. BTEST( topo_tmp(k,j,i+1), 0 ) ) &
1440	num_wall = num_wall + 1
1441	IF ( .NOT. BTEST( topo_tmp(k-1,j,i), 0 ) ) &
1442	num_wall = num_wall + 1
1443	IF ( .NOT. BTEST( topo_tmp(k+1,j,i), 0 ) ) &
1444	num_wall = num_wall + 1
1445
1446	IF ( num_wall >= 4 ) THEN
1447	num_hole_l = num_hole_l + 1
1448	!
1449	!-- Clear flag 0 and set special flag ( bit 4) to indicate
1450	!-- that new topography point is a result of filtering process.
1451	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1452	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 4 )
1453	!
1454	!-- If filled grid point is occupied by a building, classify
1455	!-- it as building grid point.
1456	IF ( building_type_f%from_file ) THEN
1457	IF ( building_type_f%var(j,i) /= &
1458	building_type_f%fill .OR. &
1459	building_type_f%var(j+1,i) /= &
1460	building_type_f%fill .OR. &
1461	building_type_f%var(j-1,i) /= &
1462	building_type_f%fill .OR. &
1463	building_type_f%var(j,i+1) /= &
1464	building_type_f%fill .OR. &
1465	building_type_f%var(j,i-1) /= &
1466	building_type_f%fill ) THEN
1467	!
1468	!-- Set flag indicating building surfaces
1469	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1470	!
1471	!-- Set building_type and ID at this position if not
1472	!-- already set. This is required for proper
1473	!-- initialization of urban-surface energy balance
1474	!-- solver.
1475	IF ( building_type_f%var(j,i) == &
1476	building_type_f%fill ) THEN
1477
1478	IF ( building_type_f%var(j+1,i) /= &
1479	building_type_f%fill ) THEN
1480	building_type_f%var(j,i) = &
1481	building_type_f%var(j+1,i)
1482	building_id_f%var(j,i) = &
1483	building_id_f%var(j+1,i)
1484	ELSEIF ( building_type_f%var(j-1,i) /= &
1485	building_type_f%fill ) THEN
1486	building_type_f%var(j,i) = &
1487	building_type_f%var(j-1,i)
1488	building_id_f%var(j,i) = &
1489	building_id_f%var(j-1,i)
1490	ELSEIF ( building_type_f%var(j,i+1) /= &
1491	building_type_f%fill ) THEN
1492	building_type_f%var(j,i) = &
1493	building_type_f%var(j,i+1)
1494	building_id_f%var(j,i) = &
1495	building_id_f%var(j,i+1)
1496	ELSEIF ( building_type_f%var(j,i-1) /= &
1497	building_type_f%fill ) THEN
1498	building_type_f%var(j,i) = &
1499	building_type_f%var(j,i-1)
1500	building_id_f%var(j,i) = &
1501	building_id_f%var(j,i-1)
1502	ENDIF
1503	ENDIF
1504	ENDIF
1505	ENDIF
1506	!
1507	!-- If filled grid point is already classified as building
1508	!-- everything is fine, else classify this grid point as
1509	!-- natural type grid point. This case, values for the
1510	!-- surface type are already set.
1511	IF ( .NOT. BTEST( topo_3d(k,j,i), 2 ) ) THEN
1512	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1513	ENDIF
1514	ENDIF
1515	ENDIF
1516	ENDDO
1517	ENDDO
1518	ENDDO
1519	!
1520	!-- Count the total number of holes, required for informative message.
1521	#if defined( __parallel )
1522	CALL MPI_ALLREDUCE( num_hole_l, num_hole, 1, MPI_INTEGER, MPI_SUM, &
1523	comm2d, ierr )
1524	#else
1525	num_hole = num_hole_l
1526	#endif
1527	IF ( num_hole > 0 .AND. .NOT. filled ) filled = .TRUE.
1528
1529	ENDDO
1530	!
1531	!-- Create an informative message if any holes were filled.
1532	IF ( filled ) THEN
1533	WRITE( message_string, * ) 'Topography was filtered, i.e. holes ' // &
1534	'resolved by only one grid point ' // &
1535	'were filled during initialization.'
1536	CALL message( 'init_grid', 'PA0430', 0, 0, 0, 6, 0 )
1537	ENDIF
1538
1539	DEALLOCATE( topo_tmp )
1540	!
1541	!-- Finally, exchange topo_3d array again and if necessary set Neumann boundary
1542	!-- condition in case of non-cyclic lateral boundaries.
1543	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1544
1545	IF ( .NOT. bc_ns_cyc ) THEN
1546	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1547	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1548	ENDIF
1549
1550	IF ( .NOT. bc_lr_cyc ) THEN
1551	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1552	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1553	ENDIF
1554	!
1555	!-- Exchange building ID and type. Note, building_type is an one-byte variable.
1556	IF ( building_id_f%from_file ) &
1557	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1558	IF ( building_type_f%from_file ) &
1559	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1560
1561	END SUBROUTINE filter_topography
1562
1563
1564	! Description:
1565	! -----------------------------------------------------------------------------!
1566	!> Reads topography information from file or sets generic topography. Moreover,
1567	!> all topography-relevant topography arrays are initialized, and grid flags
1568	!> are set.
1569	!------------------------------------------------------------------------------!
1570	SUBROUTINE init_topo( topo )
1571
1572	USE arrays_3d, &
1573	ONLY: zw
1574
1575	USE control_parameters, &
1576	ONLY: bc_lr_cyc, bc_ns_cyc, building_height, building_length_x, &
1577	building_length_y, building_wall_left, building_wall_south, &
1578	canyon_height, canyon_wall_left, canyon_wall_south, &
1579	canyon_width_x, canyon_width_y, dp_level_ind_b, dz, &
1580	message_string, topography, topography_grid_convention, &
1581	tunnel_height, tunnel_length, tunnel_width_x, tunnel_width_y, &
1582	tunnel_wall_depth
1583
1584	USE grid_variables, &
1585	ONLY: dx, dy
1586
1587	USE indices, &
1588	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
1589	nzb, nzt
1590
1591	USE kinds
1592
1593	USE netcdf_data_input_mod, &
1594	ONLY: buildings_f, terrain_height_f
1595
1596	USE pegrid
1597
1598	IMPLICIT NONE
1599
1600	INTEGER(iwp) :: bh !< temporary vertical index of building height
1601	INTEGER(iwp) :: ngp_bx !< grid point number of building size along x
1602	INTEGER(iwp) :: ngp_by !< grid point number of building size along y
1603	INTEGER(iwp) :: index_left_bwall !< index for left building wall
1604	INTEGER(iwp) :: index_right_bwall !< index for right building wall
1605	INTEGER(iwp) :: index_north_bwall !< index for north building wall
1606	INTEGER(iwp) :: index_south_bwall !< index for south building wall
1607	INTEGER(iwp) :: ch !< temporary vertical index for canyon height
1608	INTEGER(iwp) :: ngp_cx !< grid point number of canyon size along x
1609	INTEGER(iwp) :: ngp_cy !< grid point number of canyon size along y
1610	INTEGER(iwp) :: index_left_cwall !< index for left canyon wall
1611	INTEGER(iwp) :: index_right_cwall !< index for right canyon wall
1612	INTEGER(iwp) :: index_north_cwall !< index for north canyon wall
1613	INTEGER(iwp) :: index_south_cwall !< index for south canyon wall
1614	INTEGER(iwp) :: i !< index variable along x
1615	INTEGER(iwp) :: j !< index variable along y
1616	INTEGER(iwp) :: k !< index variable along z
1617	INTEGER(iwp) :: hv_in !< heavyside function to model inner tunnel surface
1618	INTEGER(iwp) :: hv_out !< heavyside function to model outer tunnel surface
1619	INTEGER(iwp) :: txe_out !< end position of outer tunnel wall in x
1620	INTEGER(iwp) :: txs_out !< start position of outer tunnel wall in x
1621	INTEGER(iwp) :: tye_out !< end position of outer tunnel wall in y
1622	INTEGER(iwp) :: tys_out !< start position of outer tunnel wall in y
1623	INTEGER(iwp) :: txe_in !< end position of inner tunnel wall in x
1624	INTEGER(iwp) :: txs_in !< start position of inner tunnel wall in x
1625	INTEGER(iwp) :: tye_in !< end position of inner tunnel wall in y
1626	INTEGER(iwp) :: tys_in !< start position of inner tunnel wall in y
1627	INTEGER(iwp) :: td !< tunnel wall depth
1628	INTEGER(iwp) :: th !< height of outer tunnel wall
1629
1630	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
1631	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
1632	!
1633	!-- Check for correct setting of the namelist parameter topography. If
1634	!-- topography information is read from file but topography = 'flat',
1635	!-- initialization does not work properly.
1636	IF ( ( buildings_f%from_file .OR. terrain_height_f%from_file ) .AND. &
1637	TRIM( topography ) /= 'read_from_file' ) THEN
1638	message_string = 'If topography information is provided (via ' // &
1639	'Netcdf or ASCII input) topography = ' // &
1640	'"read_from_file" is required.'
1641	CALL message( 'init_grid', 'PA0437', 1, 2, 0, 6, 0 )
1642	ENDIF
1643	!
1644	!-- Set outer and inner index arrays for non-flat topography.
1645	!-- Here consistency checks concerning domain size and periodicity are
1646	!-- necessary.
1647	!-- Within this SELECT CASE structure only nzb_local is initialized
1648	!-- individually depending on the chosen topography type, all other index
1649	!-- arrays are initialized further below.
1650	SELECT CASE ( TRIM( topography ) )
1651
1652	CASE ( 'flat' )
1653	!
1654	!-- Initialilize 3D topography array, used later for initializing flags
1655	topo(nzb+1:nzt+1,:,:) = IBSET( topo(nzb+1:nzt+1,:,:), 0 )
1656
1657	CASE ( 'closed_channel' )
1658	!
1659	!-- Initialilize 3D topography array, used later for initializing flags
1660	topo(nzb+1:nzt,:,:) = IBSET( topo(nzb+1:nzt,:,:), 0 )
1661
1662	CASE ( 'single_building' )
1663	!
1664	!-- Single rectangular building, by default centered in the middle of the
1665	!-- total domain
1666	ngp_bx = NINT( building_length_x / dx )
1667	ngp_by = NINT( building_length_y / dy )
1668	bh = MINLOC( ABS( zw - building_height ), 1 ) - 1
1669	IF ( ABS( zw(bh) - building_height ) == &
1670	ABS( zw(bh+1) - building_height ) ) bh = bh + 1
1671	IF ( building_wall_left == 9999999.9_wp ) THEN
1672	building_wall_left = ( nx + 1 - ngp_bx ) / 2 * dx
1673	ENDIF
1674	index_left_bwall = NINT( building_wall_left / dx )
1675	index_right_bwall = index_left_bwall + ngp_bx
1676
1677	IF ( building_wall_south == 9999999.9_wp ) THEN
1678	building_wall_south = ( ny + 1 - ngp_by ) / 2 * dy
1679	ENDIF
1680	index_south_bwall = NINT( building_wall_south / dy )
1681	index_north_bwall = index_south_bwall + ngp_by
1682
1683	!
1684	!-- Building size has to meet some requirements
1685	IF ( ( index_left_bwall < 1 ) .OR. ( index_right_bwall > nx-1 ) .OR. &
1686	( index_right_bwall < index_left_bwall+3 ) .OR. &
1687	( index_south_bwall < 1 ) .OR. ( index_north_bwall > ny-1 ) .OR.&
1688	( index_north_bwall < index_south_bwall+3 ) ) THEN
1689	WRITE( message_string, * ) 'inconsistent building parameters:', &
1690	'&index_left_bwall=', index_left_bwall, &
1691	'index_right_bwall=', index_right_bwall, &
1692	'index_south_bwall=', index_south_bwall, &
1693	'index_north_bwall=', index_north_bwall, &
1694	'nx=', nx, 'ny=', ny
1695	CALL message( 'init_grid', 'PA0203', 1, 2, 0, 6, 0 )
1696	ENDIF
1697
1698	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1699	nzb_local = 0
1700	!
1701	!-- Define the building.
1702	IF ( index_left_bwall <= nxr .AND. index_right_bwall >= nxl .AND. &
1703	index_south_bwall <= nyn .AND. index_north_bwall >= nys ) &
1704	nzb_local(MAX(nys,index_south_bwall):MIN(nyn,index_north_bwall), &
1705	MAX(nxl,index_left_bwall):MIN(nxr,index_right_bwall)) = bh
1706	!
1707	!-- Set bit array on basis of nzb_local
1708	DO i = nxl, nxr
1709	DO j = nys, nyn
1710	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1711	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1712	ENDDO
1713	ENDDO
1714
1715	DEALLOCATE( nzb_local )
1716
1717	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1718	!
1719	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1720	!-- boundary conditions for topography.
1721	IF ( .NOT. bc_ns_cyc ) THEN
1722	IF ( nys == 0 ) THEN
1723	DO i = 1, nbgp
1724	topo(:,nys-i,:) = topo(:,nys,:)
1725	ENDDO
1726	ENDIF
1727	IF ( nyn == ny ) THEN
1728	DO i = 1, nbgp
1729	topo(:,nyn+i,:) = topo(:,nyn,:)
1730	ENDDO
1731	ENDIF
1732	ENDIF
1733	IF ( .NOT. bc_lr_cyc ) THEN
1734	IF ( nxl == 0 ) THEN
1735	DO i = 1, nbgp
1736	topo(:,:,nxl-i) = topo(:,:,nxl)
1737	ENDDO
1738	ENDIF
1739	IF ( nxr == nx ) THEN
1740	DO i = 1, nbgp
1741	topo(:,:,nxr+i) = topo(:,:,nxr)
1742	ENDDO
1743	ENDIF
1744	ENDIF
1745
1746	CASE ( 'single_street_canyon' )
1747	!
1748	!-- Single quasi-2D street canyon of infinite length in x or y direction.
1749	!-- The canyon is centered in the other direction by default.
1750	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1751	!
1752	!-- Street canyon in y direction
1753	ngp_cx = NINT( canyon_width_x / dx )
1754	IF ( canyon_wall_left == 9999999.9_wp ) THEN
1755	canyon_wall_left = ( nx + 1 - ngp_cx ) / 2 * dx
1756	ENDIF
1757	index_left_cwall= NINT( canyon_wall_left / dx )
1758	index_right_cwall= index_left_cwall+ ngp_cx
1759	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1760	!
1761	!-- Street canyon in x direction
1762	ngp_cy = NINT( canyon_width_y / dy )
1763	IF ( canyon_wall_south == 9999999.9_wp ) THEN
1764	canyon_wall_south = ( ny + 1 - ngp_cy ) / 2 * dy
1765	ENDIF
1766	index_south_cwall = NINT( canyon_wall_south / dy )
1767	index_north_cwall = index_south_cwall + ngp_cy
1768
1769	ELSE
1770
1771	message_string = 'no street canyon width given'
1772	CALL message( 'init_grid', 'PA0204', 1, 2, 0, 6, 0 )
1773
1774	ENDIF
1775
1776	ch = MINLOC( ABS( zw - canyon_height ), 1 ) - 1
1777	IF ( ABS( zw(ch) - canyon_height ) == &
1778	ABS( zw(ch+1) - canyon_height ) ) ch = ch + 1
1779	dp_level_ind_b = ch
1780	!
1781	!-- Street canyon size has to meet some requirements
1782	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1783	IF ( ( index_left_cwall< 1 ) .OR. ( index_right_cwall> nx-1 ) .OR.&
1784	( ngp_cx < 3 ) .OR. ( ch < 3 ) ) THEN
1785	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1786	'&index_left_cwall=', index_left_cwall, &
1787	' index_right_cwall=', index_right_cwall, &
1788	' ngp_cx=', ngp_cx, &
1789	' ch=', ch, ' nx=', nx, ' ny=', ny
1790	CALL message( 'init_grid', 'PA0205', 1, 2, 0, 6, 0 )
1791	ENDIF
1792	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1793	IF ( ( index_south_cwall < 1 ) .OR. &
1794	( index_north_cwall > ny-1 ) .OR. ( ngp_cy < 3 ) .OR. &
1795	( ch < 3 ) ) THEN
1796	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1797	'&index_south_cwall=', index_south_cwall, &
1798	' index_north_cwall=', index_north_cwall, &
1799	' ngp_cy=', ngp_cy, &
1800	' ch=', ch, ' nx=', nx, ' ny=', ny
1801	CALL message( 'init_grid', 'PA0206', 1, 2, 0, 6, 0 )
1802	ENDIF
1803	ENDIF
1804	IF ( canyon_width_x /= 9999999.9_wp .AND. &
1805	canyon_width_y /= 9999999.9_wp ) THEN
1806	message_string = 'inconsistent canyon parameters:' // &
1807	'&street canyon can only be oriented' // &
1808	' either in x- or in y-direction'
1809	CALL message( 'init_grid', 'PA0207', 1, 2, 0, 6, 0 )
1810	ENDIF
1811
1812	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1813	nzb_local = ch
1814	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1815	IF ( index_left_cwall<= nxr .AND. index_right_cwall>= nxl ) &
1816	nzb_local(:,MAX(nxl,index_left_cwall+1):MIN(nxr,index_right_cwall-1)) = 0
1817	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1818	IF ( index_south_cwall <= nyn .AND. index_north_cwall >= nys ) &
1819	nzb_local(MAX(nys,index_south_cwall+1):MIN(nyn,index_north_cwall-1),:) = 0
1820	ENDIF
1821	!
1822	!-- Set bit array on basis of nzb_local
1823	DO i = nxl, nxr
1824	DO j = nys, nyn
1825	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1826	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1827	ENDDO
1828	ENDDO
1829	DEALLOCATE( nzb_local )
1830
1831	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1832	!
1833	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1834	!-- boundary conditions for topography.
1835	IF ( .NOT. bc_ns_cyc ) THEN
1836	IF ( nys == 0 ) THEN
1837	DO i = 1, nbgp
1838	topo(:,nys-i,:) = topo(:,nys,:)
1839	ENDDO
1840	ENDIF
1841	IF ( nyn == ny ) THEN
1842	DO i = 1, nbgp
1843	topo(:,nyn+i,:) = topo(:,nyn,:)
1844	ENDDO
1845	ENDIF
1846	ENDIF
1847	IF ( .NOT. bc_lr_cyc ) THEN
1848	IF ( nxl == 0 ) THEN
1849	DO i = 1, nbgp
1850	topo(:,:,nxl-i) = topo(:,:,nxl)
1851	ENDDO
1852	ENDIF
1853	IF ( nxr == nx ) THEN
1854	DO i = 1, nbgp
1855	topo(:,:,nxr+i) = topo(:,:,nxr)
1856	ENDDO
1857	ENDIF
1858	ENDIF
1859
1860	CASE ( 'tunnel' )
1861
1862	!
1863	!-- Tunnel height
1864	IF ( tunnel_height == 9999999.9_wp ) THEN
1865	th = zw( INT( 0.2 * nz) )
1866	ELSE
1867	th = tunnel_height
1868	ENDIF
1869	!
1870	!-- Tunnel-wall depth
1871	IF ( tunnel_wall_depth == 9999999.9_wp ) THEN
1872	td = MAX ( dx, dy, dz(1) )
1873	ELSE
1874	td = tunnel_wall_depth
1875	ENDIF
1876	!
1877	!-- Check for tunnel width
1878	IF ( tunnel_width_x == 9999999.9_wp .AND. &
1879	tunnel_width_y == 9999999.9_wp ) THEN
1880	message_string = 'No tunnel width is given. '
1881	CALL message( 'init_grid', 'PA0280', 1, 2, 0, 6, 0 )
1882	ENDIF
1883	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
1884	tunnel_width_y /= 9999999.9_wp ) THEN
1885	message_string = 'Inconsistent tunnel parameters:' // &
1886	'tunnel can only be oriented' // &
1887	'either in x- or in y-direction.'
1888	CALL message( 'init_grid', 'PA0281', 1, 2, 0, 6, 0 )
1889	ENDIF
1890	!
1891	!-- Check for too small tunnel width in x- and y-direction
1892	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
1893	tunnel_width_x - 2.0_wp * td <= 2.0_wp * dx ) THEN
1894	message_string = 'tunnel_width_x too small'
1895	CALL message( 'init_grid', 'PA0175', 1, 2, 0, 6, 0 )
1896	ENDIF
1897	IF ( tunnel_width_y /= 9999999.9_wp .AND. &
1898	tunnel_width_y - 2.0_wp * td <= 2.0_wp * dy ) THEN
1899	message_string = 'tunnel_width_y too small'
1900	CALL message( 'init_grid', 'PA0455', 1, 2, 0, 6, 0 )
1901	ENDIF
1902	!
1903	!-- Check for too large tunnel width.
1904	!-- Tunnel axis along y.
1905	IF ( tunnel_width_x /= 9999999.9_wp ) THEN
1906	IF ( tunnel_width_x > ( nx + 1 ) * dx ) THEN
1907	message_string = 'tunnel_width_x too large'
1908	CALL message( 'init_grid', 'PA0282', 1, 2, 0, 6, 0 )
1909	ENDIF
1910
1911	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_width_x * 0.5_wp )
1912	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_width_x * 0.5_wp )
1913	txs_in = INT( ( nx + 1 ) * 0.5_wp * dx - &
1914	( tunnel_width_x * 0.5_wp - td ) )
1915	txe_in = INT( ( nx + 1 ) * 0.5_wp * dx + &
1916	( tunnel_width_x * 0.5_wp - td ) )
1917
1918	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_length * 0.5_wp )
1919	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_length * 0.5_wp )
1920	tys_in = tys_out
1921	tye_in = tye_out
1922	ENDIF
1923	!
1924	!-- Tunnel axis along x.
1925	IF ( tunnel_width_y /= 9999999.9_wp ) THEN
1926	IF ( tunnel_width_y > ( ny + 1 ) * dy ) THEN
1927	message_string = 'tunnel_width_y too large'
1928	CALL message( 'init_grid', 'PA0456', 1, 2, 0, 6, 0 )
1929	ENDIF
1930
1931	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_length * 0.5_wp )
1932	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_length * 0.5_wp )
1933	txs_in = txs_out
1934	txe_in = txe_out
1935
1936	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_width_y * 0.5_wp )
1937	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_width_y * 0.5_wp )
1938	tys_in = INT( ( ny + 1 ) * 0.5_wp * dy - &
1939	( tunnel_width_y * 0.5_wp - td ) )
1940	tye_in = INT( ( ny + 1 ) * 0.5_wp * dy + &
1941	( tunnel_width_y * 0.5_wp - td ) )
1942	ENDIF
1943
1944	topo = 0
1945	DO i = nxl, nxr
1946	DO j = nys, nyn
1947	!
1948	!-- Use heaviside function to model outer tunnel surface
1949	hv_out = th * 0.5_wp * &
1950	( ( SIGN( 1.0_wp, i * dx - txs_out ) + 1.0_wp ) &
1951	- ( SIGN( 1.0_wp, i * dx - txe_out ) + 1.0_wp ) )
1952
1953	hv_out = hv_out * 0.5_wp * &
1954	( ( SIGN( 1.0_wp, j * dy - tys_out ) + 1.0_wp ) &
1955	- ( SIGN( 1.0_wp, j * dy - tye_out ) + 1.0_wp ) )
1956	!
1957	!-- Use heaviside function to model inner tunnel surface
1958	hv_in = ( th - td ) * 0.5_wp * &
1959	( ( SIGN( 1.0_wp, i * dx - txs_in ) + 1.0_wp ) &
1960	- ( SIGN( 1.0_wp, i * dx - txe_in ) + 1.0_wp ) )
1961
1962	hv_in = hv_in * 0.5_wp * &
1963	( ( SIGN( 1.0_wp, j * dy - tys_in ) + 1.0_wp ) &
1964	- ( SIGN( 1.0_wp, j * dy - tye_in ) + 1.0_wp ) )
1965	!
1966	!-- Set flags at x-y-positions without any tunnel surface
1967	IF ( hv_out - hv_in == 0.0_wp ) THEN
1968	topo(nzb+1:nzt+1,j,i) = IBSET( topo(nzb+1:nzt+1,j,i), 0 )
1969	!
1970	!-- Set flags at x-y-positions with tunnel surfaces
1971	ELSE
1972	DO k = nzb + 1, nzt + 1
1973	!
1974	!-- Inner tunnel
1975	IF ( hv_out - hv_in == th ) THEN
1976	IF ( zw(k) <= hv_out ) THEN
1977	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
1978	ELSE
1979	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
1980	ENDIF
1981	ENDIF
1982	!
1983	!-- Lateral tunnel walls
1984	IF ( hv_out - hv_in == td ) THEN
1985	IF ( zw(k) <= hv_in ) THEN
1986	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
1987	ELSEIF ( zw(k) > hv_in .AND. zw(k) <= hv_out ) THEN
1988	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
1989	ELSEIF ( zw(k) > hv_out ) THEN
1990	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
1991	ENDIF
1992	ENDIF
1993	ENDDO
1994	ENDIF
1995	ENDDO
1996	ENDDO
1997
1998	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1999	!
2000	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2001	!-- boundary conditions for topography.
2002	IF ( .NOT. bc_ns_cyc ) THEN
2003	IF ( nys == 0 ) THEN
2004	DO i = 1, nbgp
2005	topo(:,nys-i,:) = topo(:,nys,:)
2006	ENDDO
2007	ENDIF
2008	IF ( nyn == ny ) THEN
2009	DO i = 1, nbgp
2010	topo(:,nyn+i,:) = topo(:,nyn,:)
2011	ENDDO
2012	ENDIF
2013	ENDIF
2014	IF ( .NOT. bc_lr_cyc ) THEN
2015	IF ( nxl == 0 ) THEN
2016	DO i = 1, nbgp
2017	topo(:,:,nxl-i) = topo(:,:,nxl)
2018	ENDDO
2019	ENDIF
2020	IF ( nxr == nx ) THEN
2021	DO i = 1, nbgp
2022	topo(:,:,nxr+i) = topo(:,:,nxr)
2023	ENDDO
2024	ENDIF
2025	ENDIF
2026
2027	CASE ( 'read_from_file' )
2028	!
2029	!-- Note, topography information have been already read.
2030	!-- If required, further process topography, i.e. reference buildings on
2031	!-- top of orography and set temporary 3D topography array, which is
2032	!-- used later to set grid flags. Calling of this rouinte is also
2033	!-- required in case of ASCII input, even though no distinction between
2034	!-- terrain- and building height is made in this case.
2035	CALL process_topography( topo )
2036	!
2037	!-- Filter holes resolved by only one grid-point
2038	CALL filter_topography( topo )
2039	!
2040	!-- Exchange ghost-points, as well as add cyclic or Neumann boundary
2041	!-- conditions.
2042	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2043	!
2044	!-- Set lateral boundary conditions for topography on all ghost layers
2045	IF ( .NOT. bc_ns_cyc ) THEN
2046	IF ( nys == 0 ) THEN
2047	DO i = 1, nbgp
2048	topo(:,nys-i,:) = topo(:,nys,:)
2049	ENDDO
2050	ENDIF
2051	IF ( nyn == ny ) THEN
2052	DO i = 1, nbgp
2053	topo(:,nyn+i,:) = topo(:,nyn,:)
2054	ENDDO
2055	ENDIF
2056	ENDIF
2057
2058	IF ( .NOT. bc_lr_cyc ) THEN
2059	IF ( nxl == 0 ) THEN
2060	DO i = 1, nbgp
2061	topo(:,:,nxl-i) = topo(:,:,nxl)
2062	ENDDO
2063	ENDIF
2064	IF ( nxr == nx ) THEN
2065	DO i = 1, nbgp
2066	topo(:,:,nxr+i) = topo(:,:,nxr)
2067	ENDDO
2068	ENDIF
2069	ENDIF
2070
2071
2072	CASE DEFAULT
2073	!
2074	!-- The DEFAULT case is reached either if the parameter topography
2075	!-- contains a wrong character string or if the user has defined a special
2076	!-- case in the user interface. There, the subroutine user_init_grid
2077	!-- checks which of these two conditions applies.
2078	CALL user_init_grid( topo )
2079	CALL filter_topography( topo )
2080
2081	END SELECT
2082	!
2083	!-- Consistency checks and index array initialization are only required for
2084	!-- non-flat topography.
2085	IF ( TRIM( topography ) /= 'flat' ) THEN
2086	!
2087	!-- In case of non-flat topography, check whether the convention how to
2088	!-- define the topography grid has been set correctly, or whether the default
2089	!-- is applicable. If this is not possible, abort.
2090	IF ( TRIM( topography_grid_convention ) == ' ' ) THEN
2091	IF ( TRIM( topography ) /= 'closed_channel' .AND. &
2092	TRIM( topography ) /= 'single_building' .AND. &
2093	TRIM( topography ) /= 'single_street_canyon' .AND. &
2094	TRIM( topography ) /= 'tunnel' .AND. &
2095	TRIM( topography ) /= 'read_from_file') THEN
2096	!-- The default value is not applicable here, because it is only valid
2097	!-- for the four standard cases 'single_building',
2098	!-- 'single_street_canyon', 'tunnel' and 'read_from_file'
2099	!-- defined in init_grid.
2100	WRITE( message_string, * ) &
2101	'The value for "topography_grid_convention" ', &
2102	'is not set. Its default value is & only valid for ', &
2103	'"topography" = ''single_building'', ''tunnel'' ', &
2104	'''single_street_canyon'', ''closed_channel'' & or ', &
2105	'''read_from_file''.', &
2106	'& Choose ''cell_edge'' or ''cell_center''.'
2107	CALL message( 'init_grid', 'PA0239', 1, 2, 0, 6, 0 )
2108	ELSE
2109	!-- The default value is applicable here.
2110	!-- Set convention according to topography.
2111	IF ( TRIM( topography ) == 'single_building' .OR. &
2112	TRIM( topography ) == 'single_street_canyon' ) THEN
2113	topography_grid_convention = 'cell_edge'
2114	ELSEIF ( TRIM( topography ) == 'read_from_file' .OR. &
2115	TRIM( topography ) == 'tunnel') THEN
2116	topography_grid_convention = 'cell_center'
2117	ENDIF
2118	ENDIF
2119	ELSEIF ( TRIM( topography_grid_convention ) /= 'cell_edge' .AND. &
2120	TRIM( topography_grid_convention ) /= 'cell_center' ) THEN
2121	WRITE( message_string, * ) &
2122	'The value for "topography_grid_convention" is ', &
2123	'not recognized.& Choose ''cell_edge'' or ''cell_center''.'
2124	CALL message( 'init_grid', 'PA0240', 1, 2, 0, 6, 0 )
2125	ENDIF
2126
2127
2128	IF ( topography_grid_convention == 'cell_edge' ) THEN
2129	!
2130	!-- The array nzb_local as defined using the 'cell_edge' convention
2131	!-- describes the actual total size of topography which is defined at the
2132	!-- cell edges where u=0 on the topography walls in x-direction and v=0
2133	!-- on the topography walls in y-direction. However, PALM uses individual
2134	!-- arrays nzb_u\|v\|w\|s_inner\|outer that are based on nzb_s_inner.
2135	!-- Therefore, the extent of topography in nzb_local is now reduced by
2136	!-- 1dx at the E topography walls and by 1dy at the N topography walls
2137	!-- to form the basis for nzb_s_inner.
2138	!-- Note, the reverse memory access (i-j instead of j-i) is absolutely
2139	!-- required at this point.
2140	DO j = nys+1, nyn+1
2141	DO i = nxl-1, nxr
2142	DO k = nzb, nzt+1
2143	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2144	BTEST( topo(k,j,i+1), 0 ) ) &
2145	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2146	ENDDO
2147	ENDDO
2148	ENDDO
2149	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2150
2151	DO i = nxl, nxr+1
2152	DO j = nys-1, nyn
2153	DO k = nzb, nzt+1
2154	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2155	BTEST( topo(k,j+1,i), 0 ) ) &
2156	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2157	ENDDO
2158	ENDDO
2159	ENDDO
2160	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2161
2162	ENDIF
2163	ENDIF
2164
2165
2166	END SUBROUTINE init_topo
2167
2168	SUBROUTINE set_topo_flags(topo)
2169
2170	USE control_parameters, &
2171	ONLY: bc_lr_cyc, bc_ns_cyc, constant_flux_layer, &
2172	scalar_advec, topography, use_surface_fluxes, use_top_fluxes
2173
2174	USE indices, &
2175	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
2176	nzt, topo_top_ind, wall_flags_static_0, wall_flags_total_0
2177
2178	USE kinds
2179
2180	IMPLICIT NONE
2181
2182	INTEGER(iwp) :: i !< index variable along x
2183	INTEGER(iwp) :: ibit !< integer bit position of topgraphy masking array
2184	INTEGER(iwp) :: j !< index variable along y
2185	INTEGER(iwp) :: k !< index variable along z
2186
2187	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
2188
2189	ALLOCATE( wall_flags_static_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2190	wall_flags_static_0 = 0
2191	!
2192	!-- Set-up topography flags. First, set flags only for s, u, v and w-grid.
2193	!-- Further special flags will be set in following loops.
2194	DO i = nxl, nxr
2195	DO j = nys, nyn
2196	DO k = nzb, nzt+1
2197	!
2198	!-- scalar grid
2199	IF ( BTEST( topo(k,j,i), 0 ) ) &
2200	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 0 )
2201	!
2202	!-- u grid
2203	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2204	BTEST( topo(k,j,i-1), 0 ) ) &
2205	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 1 )
2206	!
2207	!-- v grid
2208	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2209	BTEST( topo(k,j-1,i), 0 ) ) &
2210	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 2 )
2211
2212	ENDDO
2213
2214	DO k = nzb, nzt
2215	!
2216	!-- w grid
2217	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2218	BTEST( topo(k+1,j,i), 0 ) ) &
2219	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 3 )
2220	ENDDO
2221
2222	IF ( topography /= 'closed_channel' ) THEN
2223	wall_flags_static_0(nzt+1,j,i) = IBSET( wall_flags_static_0(nzt+1,j,i), 3 )
2224	ENDIF
2225
2226	ENDDO
2227	ENDDO
2228
2229	CALL exchange_horiz_int( wall_flags_static_0, nys, nyn, nxl, nxr, nzt, nbgp )
2230
2231	!
2232	!-- Set outer array for scalars to mask near-surface grid points. Note, on
2233	!-- basis of flag 24 futher flags will be derived which are used to control
2234	!-- production of subgrid TKE production near walls.
2235
2236	ALLOCATE( wall_flags_total_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2237	wall_flags_total_0 = 0
2238
2239	DO i = nxl, nxr
2240	DO j = nys, nyn
2241	DO k = nzb, nzt+1
2242	wall_flags_total_0(k,j,i) = IOR( wall_flags_total_0(k,j,i), wall_flags_static_0(k,j,i) )
2243	ENDDO
2244	ENDDO
2245	ENDDO
2246
2247	CALL exchange_horiz_int( wall_flags_total_0, nys, nyn, nxl, nxr, nzt, nbgp )
2248
2249	DO i = nxl, nxr
2250	DO j = nys, nyn
2251	DO k = nzb, nzt+1
2252	IF ( BTEST( wall_flags_total_0(k,j-1,i), 0 ) .AND. &
2253	BTEST( wall_flags_total_0(k,j+1,i), 0 ) .AND. &
2254	BTEST( wall_flags_total_0(k,j,i-1), 0 ) .AND. &
2255	BTEST( wall_flags_total_0(k,j,i+1), 0 ) .AND. &
2256	BTEST( wall_flags_total_0(k,j-1,i-1), 0 ) .AND. &
2257	BTEST( wall_flags_total_0(k,j+1,i-1), 0 ) .AND. &
2258	BTEST( wall_flags_total_0(k,j-1,i+1), 0 ) .AND. &
2259	BTEST( wall_flags_total_0(k,j+1,i+1), 0 ) ) &
2260	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 24 )
2261	ENDDO
2262	ENDDO
2263	ENDDO
2264	!
2265	!-- Set further special flags
2266	DO i = nxl, nxr
2267	DO j = nys, nyn
2268	DO k = nzb, nzt+1
2269	!
2270	!-- scalar grid, former nzb_diff_s_inner.
2271	!-- Note, use this flag also to mask topography in diffusion_u and
2272	!-- diffusion_v along the vertical direction. In case of
2273	!-- use_surface_fluxes, fluxes are calculated via MOST, else, simple
2274	!-- gradient approach is applied. Please note, in case of u- and v-
2275	!-- diffuison, a small error is made at edges (on the east side for u,
2276	!-- at the north side for v), since topography on scalar grid point
2277	!-- is used instead of topography on u/v-grid. As number of topography grid
2278	!-- points on uv-grid is different than s-grid, different number of
2279	!-- surface elements would be required. In order to avoid this,
2280	!-- treat edges (u(k,j,i+1)) simply by a gradient approach, i.e. these
2281	!-- points are not masked within diffusion_u. Tests had shown that the
2282	!-- effect on the flow is negligible.
2283	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2284	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2285	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 8 )
2286	ELSE
2287	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 8 )
2288	ENDIF
2289
2290	ENDDO
2291	!
2292	!-- Special flag to control vertical diffusion at model top - former
2293	!-- nzt_diff
2294	wall_flags_total_0(:,j,i) = IBSET( wall_flags_total_0(:,j,i), 9 )
2295	IF ( use_top_fluxes ) &
2296	wall_flags_total_0(nzt+1,j,i) = IBCLR( wall_flags_total_0(nzt+1,j,i), 9 )
2297
2298
2299	DO k = nzb+1, nzt
2300	!
2301	!-- Special flag on u grid, former nzb_u_inner + 1, required
2302	!-- for disturb_field and initialization. Do not disturb directly at
2303	!-- topography, as well as initialize u with zero one grid point outside
2304	!-- of topography.
2305	IF ( BTEST( wall_flags_total_0(k-1,j,i), 1 ) .AND. &
2306	BTEST( wall_flags_total_0(k,j,i), 1 ) .AND. &
2307	BTEST( wall_flags_total_0(k+1,j,i), 1 ) ) &
2308	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 20 )
2309	!
2310	!-- Special flag on v grid, former nzb_v_inner + 1, required
2311	!-- for disturb_field and initialization. Do not disturb directly at
2312	!-- topography, as well as initialize v with zero one grid point outside
2313	!-- of topography.
2314	IF ( BTEST( wall_flags_total_0(k-1,j,i), 2 ) .AND. &
2315	BTEST( wall_flags_total_0(k,j,i), 2 ) .AND. &
2316	BTEST( wall_flags_total_0(k+1,j,i), 2 ) ) &
2317	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 21 )
2318	!
2319	!-- Special flag on scalar grid, former nzb_s_inner+1. Used for
2320	!-- lpm_sgs_tke
2321	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2322	BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2323	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2324	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 25 )
2325	!
2326	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2327	!-- in production_e
2328	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2329	IF ( BTEST( wall_flags_total_0(k,j,i), 24 ) .AND. &
2330	BTEST( wall_flags_total_0(k-1,j,i), 24 ) .AND. &
2331	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2332	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 29 )
2333	ELSE
2334	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2335	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 29 )
2336	ENDIF
2337	!
2338	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2339	!-- in production_e
2340	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2341	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2342	BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2343	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2344	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 30 )
2345	ELSE
2346	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2347	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 30 )
2348	ENDIF
2349	ENDDO
2350	!
2351	!-- Flags indicating downward facing walls
2352	DO k = nzb+1, nzt+1
2353	!
2354	!-- Scalar grid
2355	IF ( BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2356	.NOT. BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2357	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 13 )
2358	!
2359	!-- Downward facing wall on u grid
2360	IF ( BTEST( wall_flags_total_0(k-1,j,i), 1 ) .AND. &
2361	.NOT. BTEST( wall_flags_total_0(k,j,i), 1 ) ) &
2362	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 15 )
2363	!
2364	!-- Downward facing wall on v grid
2365	IF ( BTEST( wall_flags_total_0(k-1,j,i), 2 ) .AND. &
2366	.NOT. BTEST( wall_flags_total_0(k,j,i), 2 ) ) &
2367	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 17 )
2368	!
2369	!-- Downward facing wall on w grid
2370	IF ( BTEST( wall_flags_total_0(k-1,j,i), 3 ) .AND. &
2371	.NOT. BTEST( wall_flags_total_0(k,j,i), 3 ) ) &
2372	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 19 )
2373	ENDDO
2374	!
2375	!-- Flags indicating upward facing walls
2376	DO k = nzb, nzt
2377	!
2378	!-- Upward facing wall on scalar grid
2379	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2380	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2381	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 12 )
2382	!
2383	!-- Upward facing wall on u grid
2384	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 1 ) .AND. &
2385	BTEST( wall_flags_total_0(k+1,j,i), 1 ) ) &
2386	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 14 )
2387
2388	!
2389	!-- Upward facing wall on v grid
2390	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 2 ) .AND. &
2391	BTEST( wall_flags_total_0(k+1,j,i), 2 ) ) &
2392	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 16 )
2393
2394	!
2395	!-- Upward facing wall on w grid
2396	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 3 ) .AND. &
2397	BTEST( wall_flags_total_0(k+1,j,i), 3 ) ) &
2398	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 18 )
2399	!
2400	!-- Special flag on scalar grid, former nzb_s_inner
2401	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .OR. &
2402	BTEST( wall_flags_total_0(k,j,i), 12 ) .OR. &
2403	BTEST( wall_flags_total_0(k,j,i), 13 ) ) &
2404	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 22 )
2405	!
2406	!-- Special flag on scalar grid, nzb_diff_s_inner - 1, required for
2407	!-- flow_statistics
2408	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2409	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2410	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2411	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 23 )
2412	ELSE
2413	IF ( BTEST( wall_flags_total_0(k,j,i), 22 ) ) &
2414	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 23 )
2415	ENDIF
2416
2417
2418	ENDDO
2419	wall_flags_total_0(nzt+1,j,i) = IBSET( wall_flags_total_0(nzt+1,j,i), 22 )
2420	wall_flags_total_0(nzt+1,j,i) = IBSET( wall_flags_total_0(nzt+1,j,i), 23 )
2421	!
2422	!-- Set flags indicating that topography is close by in horizontal
2423	!-- direction, i.e. flags that infold the topography. These will be used
2424	!-- to set advection flags for passive scalars, where due to large
2425	!-- gradients near buildings stationary numerical oscillations can produce
2426	!-- unrealistically high concentrations. This is only necessary if
2427	!-- WS-scheme is applied for scalar advection. Note, these flags will be
2428	!-- only used for passive scalars such as chemical species or aerosols.
2429	IF ( scalar_advec == 'ws-scheme' ) THEN
2430	DO k = nzb, nzt
2431	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. ( &
2432	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-1), 0 ) ) .OR.&
2433	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-2), 0 ) ) .OR.&
2434	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-3), 0 ) ) .OR.&
2435	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+1), 0 ) ) .OR.&
2436	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+2), 0 ) ) .OR.&
2437	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+3), 0 ) ) .OR.&
2438	ANY( .NOT. BTEST( wall_flags_total_0(k,j-1,i-3:i+3), 0 ) ) .OR.&
2439	ANY( .NOT. BTEST( wall_flags_total_0(k,j-2,i-3:i+3), 0 ) ) .OR.&
2440	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3,i-3:i+3), 0 ) ) .OR.&
2441	ANY( .NOT. BTEST( wall_flags_total_0(k,j+1,i-3:i+3), 0 ) ) .OR.&
2442	ANY( .NOT. BTEST( wall_flags_total_0(k,j+2,i-3:i+3), 0 ) ) .OR.&
2443	ANY( .NOT. BTEST( wall_flags_total_0(k,j+3,i-3:i+3), 0 ) ) &
2444	) ) &
2445	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 31 )
2446
2447	ENDDO
2448	ENDIF
2449	ENDDO
2450	ENDDO
2451	!
2452	!-- Finally, set identification flags indicating natural terrain or buildings.
2453	!-- Natural terrain grid points. Information on the type of the surface is
2454	!-- stored in bit 1 of 3D Integer array topo. However, this bit is only set
2455	!-- when topography is read from file. In order to run the land-surface model
2456	!-- also without topography information, set bit 1 explicitely in this case.
2457	!--
2458	!-- Natural terrain grid points
2459	!-- If no topography is initialized, the land-surface is at k = nzb.
2460	IF ( TRIM( topography ) /= 'read_from_file' ) THEN
2461	wall_flags_static_0(nzb,:,:) = IBSET( wall_flags_static_0(nzb,:,:), 5 )
2462	ELSE
2463	DO i = nxl, nxr
2464	DO j = nys, nyn
2465	DO k = nzb, nzt+1
2466	!
2467	!-- Natural terrain grid point
2468	IF ( BTEST( topo(k,j,i), 1 ) ) &
2469	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 5 )
2470	ENDDO
2471	ENDDO
2472	ENDDO
2473	ENDIF
2474	!
2475	!-- Building grid points.
2476	DO i = nxl, nxr
2477	DO j = nys, nyn
2478	DO k = nzb, nzt+1
2479	IF ( BTEST( topo(k,j,i), 2 ) ) &
2480	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 6 )
2481	ENDDO
2482	ENDDO
2483	ENDDO
2484	!
2485	!-- Set flag 4, indicating new topography grid points due to filtering.
2486	DO i = nxl, nxr
2487	DO j = nys, nyn
2488	DO k = nzb, nzt+1
2489	IF ( BTEST( topo(k,j,i), 4 ) ) &
2490	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 4 )
2491	ENDDO
2492	ENDDO
2493	ENDDO
2494
2495	CALL exchange_horiz_int( wall_flags_static_0, nys, nyn, nxl, nxr, nzt, nbgp )
2496
2497	DO i = nxl, nxr
2498	DO j = nys, nyn
2499	DO k = nzb, nzt+1
2500	wall_flags_total_0(k,j,i) = IOR( wall_flags_total_0(k,j,i), wall_flags_static_0(k,j,i) )
2501	ENDDO
2502	ENDDO
2503	ENDDO
2504	!
2505	!-- Exchange ghost points for wall flags
2506	CALL exchange_horiz_int( wall_flags_total_0, nys, nyn, nxl, nxr, nzt, nbgp )
2507	!
2508	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2509	!-- boundary conditions for topography.
2510	IF ( .NOT. bc_ns_cyc ) THEN
2511	IF ( nys == 0 ) THEN
2512	DO i = 1, nbgp
2513	wall_flags_total_0(:,nys-i,:) = wall_flags_total_0(:,nys,:)
2514	ENDDO
2515	ENDIF
2516	IF ( nyn == ny ) THEN
2517	DO i = 1, nbgp
2518	wall_flags_total_0(:,nyn+i,:) = wall_flags_total_0(:,nyn,:)
2519	ENDDO
2520	ENDIF
2521	ENDIF
2522	IF ( .NOT. bc_lr_cyc ) THEN
2523	IF ( nxl == 0 ) THEN
2524	DO i = 1, nbgp
2525	wall_flags_total_0(:,:,nxl-i) = wall_flags_total_0(:,:,nxl)
2526	ENDDO
2527	ENDIF
2528	IF ( nxr == nx ) THEN
2529	DO i = 1, nbgp
2530	wall_flags_total_0(:,:,nxr+i) = wall_flags_total_0(:,:,nxr)
2531	ENDDO
2532	ENDIF
2533	ENDIF
2534	!
2535	!-- Pre-calculate topography top indices (former get_topography_top_index
2536	!-- function)
2537	ALLOCATE( topo_top_ind(nysg:nyng,nxlg:nxrg,0:4) )
2538	!
2539	!-- Uppermost topography index on scalar grid
2540	ibit = 12
2541	topo_top_ind(:,:,0) = MAXLOC( &
2542	MERGE( 1, 0, &
2543	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2544	), DIM = 1 &
2545	) - 1
2546	!
2547	!-- Uppermost topography index on u grid
2548	ibit = 14
2549	topo_top_ind(:,:,1) = MAXLOC( &
2550	MERGE( 1, 0, &
2551	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2552	), DIM = 1 &
2553	) - 1
2554	!
2555	!-- Uppermost topography index on v grid
2556	ibit = 16
2557	topo_top_ind(:,:,2) = MAXLOC( &
2558	MERGE( 1, 0, &
2559	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2560	), DIM = 1 &
2561	) - 1
2562	!
2563	!-- Uppermost topography index on w grid
2564	ibit = 18
2565	topo_top_ind(:,:,3) = MAXLOC( &
2566	MERGE( 1, 0, &
2567	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2568	), DIM = 1 &
2569	) - 1
2570	!
2571	!-- Uppermost topography index on scalar outer grid
2572	ibit = 24
2573	topo_top_ind(:,:,4) = MAXLOC( &
2574	MERGE( 1, 0, &
2575	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2576	), DIM = 1 &
2577	) - 1
2578
2579	END SUBROUTINE set_topo_flags
2580
2581
2582
2583

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