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source: palm/trunk/SOURCE/init_grid.f90 @ 4454

Last change on this file since 4454 was 4444, checked in by raasch, 5 years ago
bugfix: cpp-directives for serial mode added
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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 4444 2020-03-05 15:59:50Z forkel $
27	! bugfix: cpp-directives for serial mode added
28	!
29	! 4414 2020-02-19 20:16:04Z suehring
30	! - Remove deprecated topography arrays nzb_s_inner, nzb_u_inner, etc.
31	! - Move initialization of boundary conditions and multigrid into an extra
32	! module interface.
33	!
34	! 4386 2020-01-27 15:07:30Z Giersch
35	! Allocation statements, comments, naming of variables revised and _wp added to
36	! real type values
37	!
38	! 4360 2020-01-07 11:25:50Z suehring
39	! Revise error messages for generic tunnel setup.
40	!
41	! 4346 2019-12-18 11:55:56Z motisi
42	! Introduction of wall_flags_total_0, which currently sets bits based on static
43	! topography information used in wall_flags_static_0
44	!
45	! 4340 2019-12-16 08:17:03Z Giersch
46	! Topography closed channel flow with symmetric boundaries implemented
47	!
48	! 4329 2019-12-10 15:46:36Z motisi
49	! Renamed wall_flags_0 to wall_flags_static_0
50	!
51	! 4328 2019-12-09 18:53:04Z suehring
52	! Minor change in nzb_max computation. Commentation added.
53	!
54	! 4314 2019-11-29 10:29:20Z suehring
55	! Set additional topography flag 4 to mark topography grid points emerged
56	! from the filtering process.
57	!
58	! 4294 2019-11-13 18:34:16Z suehring
59	! Bugfix, always set bit 5 and 6 of wall_flags, indicating terrain- and
60	! building surfaces in all cases, in order to enable terrain-following output
61	! also when no land- or urban-surface model is applied.
62	!
63	! 4265 2019-10-15 16:16:24Z suehring
64	! Bugfix for last commit, exchange oro_max variable only when it is allocated
65	! (not necessarily the case when topography is input from ASCII file).
66	!
67	! 4245 2019-09-30 08:40:37Z pavelkrc
68	! Store oro_max (building z-offset) in 2D for building surfaces
69	!
70	! 4189 2019-08-26 16:19:38Z suehring
71	! - Add check for proper setting of namelist parameter topography
72	! - Set flag to indicate land surfaces in case no topography is provided
73	!
74	! 4182 2019-08-22 15:20:23Z scharf
75	! Corrected "Former revisions" section
76	!
77	! 4168 2019-08-16 13:50:17Z suehring
78	! Pre-calculate topography top index and store it on an array (replaces former
79	! functions get_topography_top_index)
80	!
81	! 4159 2019-08-15 13:31:35Z suehring
82	! Revision of topography processing. This was not consistent between 2D and 3D
83	! buildings.
84	!
85	! 4144 2019-08-06 09:11:47Z raasch
86	! relational operators .EQ., .NE., etc. replaced by ==, /=, etc.
87	!
88	! 4115 2019-07-24 12:50:49Z suehring
89	! Bugfix in setting near-surface flag 24, inidicating wall-bounded grid points
90	!
91	! 4110 2019-07-22 17:05:21Z suehring
92	! - Separate initialization of advection flags for momentum and scalars.
93	! - Change subroutine interface for ws_init_flags_scalar to pass boundary flags
94	!
95	! 4109 2019-07-22 17:00:34Z suehring
96	! Fix bad commit
97	!
98	! 3926 2019-04-23 12:56:42Z suehring
99	! Minor bugfix in building mapping when all building IDs in the model domain
100	! are missing
101	!
102	! 3857 2019-04-03 13:00:16Z knoop
103	! In projection of non-building 3D objects onto numerical grid remove
104	! dependency on building_type
105	!
106	! 3763 2019-02-25 17:33:49Z suehring
107	! Replace work-around for ghost point exchange of 1-byte arrays with specific
108	! routine as already done in other routines
109	!
110	! 3761 2019-02-25 15:31:42Z raasch
111	! unused variables removed
112	!
113	! 3661 2019-01-08 18:22:50Z suehring
114	! Remove setting of nzb_max to nzt at non-cyclic boundary PEs, instead,
115	! order degradation of advection scheme is handeled directly in advec_ws
116	!
117	! 3655 2019-01-07 16:51:22Z knoop
118	! Comment added
119	!
120	! Revision 1.1 1997/08/11 06:17:45 raasch
121	! Initial revision (Testversion)
122	!
123	!
124	! Description:
125	! -----------------------------------------------------------------------------!
126	!> Creating grid depending constants
127	!> @todo: Rearrange topo flag list
128	!> @todo: reference 3D buildings on top of orography is not tested and may need
129	!> further improvement for steep slopes
130	!> @todo: Use more advanced setting of building type at filled holes
131	!------------------------------------------------------------------------------!
132	SUBROUTINE init_grid
133
134	USE arrays_3d, &
135	ONLY: dd2zu, ddzu, ddzu_pres, ddzw, dzu, dzw, x, xu, y, yv, zu, zw
136
137	USE control_parameters, &
138	ONLY: constant_flux_layer, dz, dz_max, dz_stretch_factor, &
139	dz_stretch_factor_array, dz_stretch_level, dz_stretch_level_end,&
140	dz_stretch_level_end_index, dz_stretch_level_start_index, &
141	dz_stretch_level_start, ibc_uv_b, message_string, &
142	number_stretch_level_end, &
143	number_stretch_level_start, &
144	ocean_mode, &
145	psolver, &
146	symmetry_flag, &
147	topography, &
148	use_surface_fluxes
149
150	USE grid_variables, &
151	ONLY: ddx, ddx2, ddy, ddy2, dx, dx2, dy, dy2, zu_s_inner, zw_w_inner
152
153	USE indices, &
154	ONLY: nbgp, &
155	nx, &
156	nxl, &
157	nxlg, &
158	nxr, &
159	nxrg, &
160	ny, &
161	nyn, &
162	nyng, &
163	nys, &
164	nysg, &
165	nz, &
166	nzb, &
167	nzb_diff, &
168	nzb_max, &
169	nzt, &
170	topo_top_ind, &
171	topo_min_level
172
173	USE kinds
174
175	USE pegrid
176
177	#if defined( __parallel )
178	USE vertical_nesting_mod, &
179	ONLY: vnested, vnest_init_grid
180	#endif
181
182	IMPLICIT NONE
183
184	INTEGER(iwp) :: i !< index variable along x
185	INTEGER(iwp) :: j !< index variable along y
186	INTEGER(iwp) :: k !< index variable along z
187	INTEGER(iwp) :: k_top !< topography top index on local PE
188	INTEGER(iwp) :: n !< loop variable for stretching
189	INTEGER(iwp) :: number_dz !< number of user-specified dz values
190	INTEGER(iwp) :: nzb_local_max !< vertical grid index of maximum topography height
191	INTEGER(iwp) :: nzb_local_min !< vertical grid index of minimum topography height
192
193	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
194
195	REAL(wp) :: dz_level_end !< distance between calculated height level for u/v-grid and user-specified end level for stretching
196	REAL(wp) :: dz_stretched !< stretched vertical grid spacing
197
198	REAL(wp), DIMENSION(:), ALLOCATABLE :: min_dz_stretch_level_end !< Array that contains all minimum heights where the stretching can end
199
200
201	!
202	!-- Calculation of horizontal array bounds including ghost layers
203	nxlg = nxl - nbgp
204	nxrg = nxr + nbgp
205	nysg = nys - nbgp
206	nyng = nyn + nbgp
207
208	!
209	!-- Allocate grid arrays
210	ALLOCATE( x(0:nx) )
211	ALLOCATE( xu(0:nx) )
212
213	DO i = 0, nx
214	xu(i) = i * dx
215	x(i) = i * dx + 0.5_wp * dx
216	ENDDO
217
218	ALLOCATE( y(0:ny) )
219	ALLOCATE( yv(0:ny) )
220
221	DO j = 0, ny
222	yv(j) = j * dy
223	y(j) = j * dy + 0.5_wp * dy
224	ENDDO
225
226	ALLOCATE( ddzu(1:nzt+1) )
227	ALLOCATE( ddzw(1:nzt+1) )
228	ALLOCATE( dd2zu(1:nzt) )
229	ALLOCATE( dzu(1:nzt+1) )
230	ALLOCATE( dzw(1:nzt+1) )
231	ALLOCATE( zu(nzb:nzt+1) )
232	ALLOCATE( zw(nzb:nzt+1) )
233
234	!
235	!-- For constructing an appropriate grid, the vertical grid spacing dz has to
236	!-- be specified with a non-negative value in the parameter file
237	IF ( dz(1) == -1.0_wp ) THEN
238	message_string = 'missing dz'
239	CALL message( 'init_grid', 'PA0200', 1, 2, 0, 6, 0 )
240	ELSEIF ( dz(1) <= 0.0_wp ) THEN
241	WRITE( message_string, * ) 'dz=',dz(1),' <= 0.0'
242	CALL message( 'init_grid', 'PA0201', 1, 2, 0, 6, 0 )
243	ENDIF
244
245	!
246	!-- Initialize dz_stretch_level_start with the value of dz_stretch_level
247	!-- if it was set by the user
248	IF ( dz_stretch_level /= -9999999.9_wp ) THEN
249	dz_stretch_level_start(1) = dz_stretch_level
250	ENDIF
251
252	!
253	!-- Determine number of dz values and stretching levels specified by the
254	!-- user to allow right controlling of the stretching mechanism and to
255	!-- perform error checks. The additional requirement that dz /= dz_max
256	!-- for counting number of user-specified dz values is necessary. Otherwise
257	!-- restarts would abort if the old stretching mechanism with dz_stretch_level
258	!-- is used (Attention: The user is not allowed to specify a dz value equal
259	!-- to the default of dz_max = 999.0).
260	number_dz = COUNT( dz /= -1.0_wp .AND. dz /= dz_max)
261	number_stretch_level_start = COUNT( dz_stretch_level_start /= &
262	-9999999.9_wp )
263	number_stretch_level_end = COUNT( dz_stretch_level_end /= &
264	9999999.9_wp )
265
266	!
267	!-- The number of specified end levels +1 has to be the same as the number
268	!-- of specified dz values
269	IF ( number_dz /= number_stretch_level_end + 1 ) THEN
270	WRITE( message_string, * ) 'The number of values for dz = ', &
271	number_dz, 'has to be the same as& ', &
272	'the number of values for ', &
273	'dz_stretch_level_end + 1 = ', &
274	number_stretch_level_end+1
275	CALL message( 'init_grid', 'PA0156', 1, 2, 0, 6, 0 )
276	ENDIF
277
278	!
279	!-- The number of specified start levels has to be the same or one less than
280	!-- the number of specified dz values
281	IF ( number_dz /= number_stretch_level_start + 1 .AND. &
282	number_dz /= number_stretch_level_start ) THEN
283	WRITE( message_string, * ) 'The number of values for dz = ', &
284	number_dz, 'has to be the same as or one ', &
285	'more than& the number of values for ', &
286	'dz_stretch_level_start = ', &
287	number_stretch_level_start
288	CALL message( 'init_grid', 'PA0211', 1, 2, 0, 6, 0 )
289	ENDIF
290
291	!-- The number of specified start levels has to be the same or one more than
292	!-- the number of specified end levels
293	IF ( number_stretch_level_start /= number_stretch_level_end + 1 .AND. &
294	number_stretch_level_start /= number_stretch_level_end ) THEN
295	WRITE( message_string, * ) 'The number of values for ', &
296	'dz_stretch_level_start = ', &
297	dz_stretch_level_start, 'has to be the ', &
298	'same or one more than& the number of ', &
299	'values for dz_stretch_level_end = ', &
300	number_stretch_level_end
301	CALL message( 'init_grid', 'PA0216', 1, 2, 0, 6, 0 )
302	ENDIF
303
304	!
305	!-- Initialize dz for the free atmosphere with the value of dz_max
306	IF ( dz(number_stretch_level_start+1) == -1.0_wp .AND. &
307	number_stretch_level_start /= 0 ) THEN
308	dz(number_stretch_level_start+1) = dz_max
309	ENDIF
310
311	!
312	!-- Initialize the stretching factor if (infinitely) stretching in the free
313	!-- atmosphere is desired (dz_stretch_level_end was not specified for the
314	!-- free atmosphere)
315	IF ( number_stretch_level_start == number_stretch_level_end + 1 ) THEN
316	dz_stretch_factor_array(number_stretch_level_start) = &
317	dz_stretch_factor
318	ENDIF
319
320	!
321	!-- Allocation of arrays for stretching
322	ALLOCATE( min_dz_stretch_level_end(number_stretch_level_start) )
323
324	!
325	!-- Define the vertical grid levels. Start with atmosphere branch
326	IF ( .NOT. ocean_mode ) THEN
327
328	!
329	!-- The stretching region has to be large enough to allow for a smooth
330	!-- transition between two different grid spacings. The number 4 is an
331	!-- empirical value
332	DO n = 1, number_stretch_level_start
333	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) + &
334	4 * MAX( dz(n),dz(n+1) )
335	ENDDO
336
337	IF ( ANY( min_dz_stretch_level_end(1:number_stretch_level_start) > &
338	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
339	message_string= 'Each dz_stretch_level_end has to be larger ' // &
340	'than its corresponding value for &' // &
341	'dz_stretch_level_start + 4*MAX(dz(n),dz(n+1)) '//&
342	'to allow for smooth grid stretching'
343	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
344	ENDIF
345
346	!
347	!-- Stretching must not be applied within the surface layer
348	!-- (first two grid points). For the default case dz_stretch_level_start
349	!-- is negative. Therefore the absolut value is checked here.
350	IF ( ANY( ABS( dz_stretch_level_start ) <= dz(1) * 1.5_wp ) ) THEN
351	WRITE( message_string, * ) 'Each dz_stretch_level_start has to be ',&
352	'larger than ', dz(1) * 1.5
353	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
354	ENDIF
355
356	!
357	!-- The stretching has to start and end on a grid level. Therefore
358	!-- user-specified values are mapped to the next lowest level. The
359	!-- calculation of the first level is realized differently just because of
360	!-- historical reasons (the advanced/new stretching mechanism was realized
361	!-- in a way that results don't change if the old parameters
362	!-- dz_stretch_level, dz_stretch_factor and dz_max are used)
363	IF ( number_stretch_level_start /= 0 ) THEN
364	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) - &
365	dz(1)/2.0) / dz(1) ) &
366	* dz(1) + dz(1)/2.0
367	ENDIF
368
369	IF ( number_stretch_level_start > 1 ) THEN
370	DO n = 2, number_stretch_level_start
371	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
372	dz(n) ) * dz(n)
373	ENDDO
374	ENDIF
375
376	IF ( number_stretch_level_end /= 0 ) THEN
377	DO n = 1, number_stretch_level_end
378	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
379	dz(n+1) ) * dz(n+1)
380	ENDDO
381	ENDIF
382
383	!
384	!-- Determine stretching factor if necessary
385	IF ( number_stretch_level_end >= 1 ) THEN
386	CALL calculate_stretching_factor( number_stretch_level_end )
387	ENDIF
388
389	!
390	!-- Grid for atmosphere with surface at z=0 (k=0, w-grid).
391	!-- First compute the u- and v-levels. In case of dirichlet bc for u and v
392	!-- the first u/v- and w-level (k=0) are defined at same height (z=0).
393	!-- The second u-level (k=1) corresponds to the top of the
394	!-- surface layer. In case of symmetric boundaries (closed channel flow),
395	!-- the first grid point is always at z=0.
396	IF ( ibc_uv_b == 0 .OR. ibc_uv_b == 2 .OR. &
397	topography == 'closed_channel' ) THEN
398	zu(0) = 0.0_wp
399	ELSE
400	zu(0) = - dz(1) * 0.5_wp
401	ENDIF
402
403	zu(1) = dz(1) * 0.5_wp
404
405	!
406	!-- Determine u and v height levels considering the possibility of grid
407	!-- stretching in several heights.
408	n = 1
409	dz_stretch_level_start_index = nzt+1
410	dz_stretch_level_end_index = nzt+1
411	dz_stretched = dz(1)
412
413	!-- The default value of dz_stretch_level_start is negative, thus the first
414	!-- condition is true even if no stretching shall be applied. Hence, the
415	!-- second condition is also necessary.
416	DO k = 2, nzt+1-symmetry_flag
417	IF ( dz_stretch_level_start(n) <= zu(k-1) .AND. &
418	dz_stretch_level_start(n) /= -9999999.9_wp ) THEN
419	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
420
421	IF ( dz(n) > dz(n+1) ) THEN
422	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
423	ELSE
424	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
425	ENDIF
426
427	IF ( dz_stretch_level_start_index(n) == nzt+1 ) &
428	dz_stretch_level_start_index(n) = k-1
429
430	ENDIF
431
432	zu(k) = zu(k-1) + dz_stretched
433
434	!
435	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
436	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
437
438	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
439	zu(k) = dz_stretch_level_end(n)
440	dz_stretched = dz(n+1)
441	dz_stretch_level_end_index(n) = k
442	n = n + 1
443	ENDIF
444	ENDDO
445
446	!
447	!-- If a closed channel flow is simulated, make sure that grid structure is
448	!-- the same for both bottom and top boundary. (Hint: Using a different dz
449	!-- at the bottom and at the top makes no sense due to symmetric boundaries
450	!-- where dz should be equal. Therefore, different dz at the bottom and top
451	!-- causes an abort (see check_parameters).)
452	IF ( topography == 'closed_channel' ) THEN
453	zu(nzt+1) = zu(nzt) + dz(1) * 0.5_wp
454	ENDIF
455
456	!
457	!-- Compute the w-levels. They are always staggered half-way between the
458	!-- corresponding u-levels. In case of dirichlet bc for u and v at the
459	!-- ground the first u- and w-level (k=0) are defined at same height (z=0).
460	!-- Per default, the top w-level is extrapolated linearly. In case of
461	!-- a closed channel flow, zu(nzt+1) and zw(nzt) must be set explicitely.
462	!-- (Hint: Using a different dz at the bottom and at the top makes no sense
463	!-- due to symmetric boundaries where dz should be equal. Therefore,
464	!-- different dz at the bottom and top causes an abort (see
465	!-- check_parameters).)
466	zw(0) = 0.0_wp
467	DO k = 1, nzt-symmetry_flag
468	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
469	ENDDO
470	IF ( topography == 'closed_channel' ) THEN
471	zw(nzt) = zw(nzt-1) + dz(1)
472	zw(nzt+1) = zw(nzt) + dz(1)
473	ELSE
474	zw(nzt+1) = zw(nzt) + 2.0_wp * ( zu(nzt+1) - zw(nzt) )
475	ENDIF
476
477	ELSE !ocean branch
478
479	!
480	!-- The stretching region has to be large enough to allow for a smooth
481	!-- transition between two different grid spacings. The number 4 is an
482	!-- empirical value
483	DO n = 1, number_stretch_level_start
484	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) - &
485	4 * MAX( dz(n),dz(n+1) )
486	ENDDO
487
488	IF ( ANY( min_dz_stretch_level_end (1:number_stretch_level_start) < &
489	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
490	message_string= 'Each dz_stretch_level_end has to be less ' // &
491	'than its corresponding value for &' // &
492	'dz_stretch_level_start - 4*MAX(dz(n),dz(n+1)) '//&
493	'to allow for smooth grid stretching'
494	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
495	ENDIF
496
497	!
498	!-- Stretching must not be applied close to the surface (last two grid
499	!-- points). For the default case dz_stretch_level_start is negative.
500	IF ( ANY( dz_stretch_level_start >= - dz(1) * 1.5_wp ) ) THEN
501	WRITE( message_string, * ) 'Each dz_stretch_level_start has to be ',&
502	'less than ', -dz(1) * 1.5
503	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
504	ENDIF
505
506	!
507	!-- The stretching has to start and end on a grid level. Therefore
508	!-- user-specified values are mapped to the next highest level. The
509	!-- calculation of the first level is realized differently just because of
510	!-- historical reasons (the advanced/new stretching mechanism was realized
511	!-- in a way that results don't change if the old parameters
512	!-- dz_stretch_level, dz_stretch_factor and dz_max are used)
513	IF ( number_stretch_level_start /= 0 ) THEN
514	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) + &
515	dz(1)/2.0) / dz(1) ) &
516	* dz(1) - dz(1)/2.0
517	ENDIF
518
519	IF ( number_stretch_level_start > 1 ) THEN
520	DO n = 2, number_stretch_level_start
521	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
522	dz(n) ) * dz(n)
523	ENDDO
524	ENDIF
525
526	IF ( number_stretch_level_end /= 0 ) THEN
527	DO n = 1, number_stretch_level_end
528	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
529	dz(n+1) ) * dz(n+1)
530	ENDDO
531	ENDIF
532
533	!
534	!-- Determine stretching factor if necessary
535	IF ( number_stretch_level_end >= 1 ) THEN
536	CALL calculate_stretching_factor( number_stretch_level_end )
537	ENDIF
538
539	!
540	!-- Grid for ocean with free water surface is at k=nzt (w-grid).
541	!-- In case of neumann bc at the ground the first first u-level (k=0) lies
542	!-- below the first w-level (k=0). In case of dirichlet bc the first u- and
543	!-- w-level are defined at same height, but staggered from the second level.
544	!-- The second u-level (k=1) corresponds to the top of the surface layer.
545	!-- z values are negative starting from z=0 (surface)
546	zu(nzt+1) = dz(1) * 0.5_wp
547	zu(nzt) = - dz(1) * 0.5_wp
548
549	!
550	!-- Determine u and v height levels considering the possibility of grid
551	!-- stretching in several heights.
552	n = 1
553	dz_stretch_level_start_index = 0
554	dz_stretch_level_end_index = 0
555	dz_stretched = dz(1)
556
557	DO k = nzt-1, 0, -1
558
559	IF ( dz_stretch_level_start(n) >= zu(k+1) ) THEN
560	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
561
562	IF ( dz(n) > dz(n+1) ) THEN
563	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
564	ELSE
565	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
566	ENDIF
567
568	IF ( dz_stretch_level_start_index(n) == 0 ) &
569	dz_stretch_level_start_index(n) = k+1
570
571	ENDIF
572
573	zu(k) = zu(k+1) - dz_stretched
574
575	!
576	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
577	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
578
579	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
580	zu(k) = dz_stretch_level_end(n)
581	dz_stretched = dz(n+1)
582	dz_stretch_level_end_index(n) = k
583	n = n + 1
584	ENDIF
585	ENDDO
586
587	!
588	!-- Compute the w-levels. They are always staggered half-way between the
589	!-- corresponding u-levels, except in case of dirichlet bc for u and v
590	!-- at the ground. In this case the first u- and w-level are defined at
591	!-- same height. The top w-level (nzt+1) is not used but set for
592	!-- consistency, since w and all scalar variables are defined up tp nzt+1.
593	zw(nzt+1) = dz(1)
594	zw(nzt) = 0.0_wp
595	DO k = 0, nzt
596	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
597	ENDDO
598
599	!
600	!-- In case of dirichlet bc for u and v the first u- and w-level are defined
601	!-- at same height.
602	IF ( ibc_uv_b == 0 ) THEN
603	zu(0) = zw(0)
604	ENDIF
605
606	ENDIF !End of defining the vertical grid levels
607
608	!
609	!-- Compute grid lengths.
610	DO k = 1, nzt+1
611	dzu(k) = zu(k) - zu(k-1)
612	ddzu(k) = 1.0_wp / dzu(k)
613	dzw(k) = zw(k) - zw(k-1)
614	ddzw(k) = 1.0_wp / dzw(k)
615	ENDDO
616
617	DO k = 1, nzt
618	dd2zu(k) = 1.0_wp / ( dzu(k) + dzu(k+1) )
619	ENDDO
620
621	!
622	!-- The FFT- SOR-pressure solvers assume grid spacings of a staggered grid
623	!-- everywhere. For the actual grid, the grid spacing at the lowest level
624	!-- is only dz/2, but should be dz. Therefore, an additional array
625	!-- containing with appropriate grid information is created for these
626	!-- solvers.
627	IF ( psolver(1:9) /= 'multigrid' ) THEN
628	ALLOCATE( ddzu_pres(1:nzt+1) )
629	ddzu_pres = ddzu
630	ddzu_pres(1) = ddzu_pres(2) ! change for lowest level
631	ENDIF
632
633	!
634	!-- Compute the reciprocal values of the horizontal grid lengths.
635	ddx = 1.0_wp / dx
636	ddy = 1.0_wp / dy
637	dx2 = dx * dx
638	dy2 = dy * dy
639	ddx2 = 1.0_wp / dx2
640	ddy2 = 1.0_wp / dy2
641
642	!
643	!-- Allocate 3D array to set topography
644	ALLOCATE( topo(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
645	topo = 0
646	!
647	!-- Initialize topography by generic topography or read topography from file.
648	CALL init_topo( topo )
649	!
650	!-- Set flags to mask topography on the grid.
651	CALL set_topo_flags( topo )
652
653	!
654	!-- Determine the maximum level of topography. It is used for
655	!-- steering the degradation of order of the applied advection scheme,
656	!-- as well in the lpm.
657	k_top = 0
658	DO i = nxl, nxr
659	DO j = nys, nyn
660	DO k = nzb, nzt + 1
661	k_top = MAX( k_top, MERGE( k, 0, .NOT. BTEST( topo(k,j,i), 0 ) ) )
662	ENDDO
663	ENDDO
664	ENDDO
665	#if defined( __parallel )
666	CALL MPI_ALLREDUCE( k_top, nzb_max, 1, MPI_INTEGER, &
667	MPI_MAX, comm2d, ierr )
668	#else
669	nzb_max = k_top
670	#endif
671	!
672	!-- Increment nzb_max by 1 in order to allow for proper diverengence correction.
673	!-- Further, in case topography extents up to the model top, limit to nzt.
674	nzb_max = MIN( nzb_max+1, nzt )
675	!
676	!-- Determine minimum index of topography. Usually, this will be nzb. In case
677	!-- there is elevated topography, however, the lowest topography will be higher.
678	!-- This index is e.g. used to calculate mean first-grid point atmosphere
679	!-- temperature, surface pressure and density, etc. .
680	topo_min_level = 0
681	#if defined( __parallel )
682	CALL MPI_ALLREDUCE( MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
683	topo_min_level, 1, MPI_INTEGER, MPI_MIN, comm2d, ierr )
684	#else
685	topo_min_level = MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
686	#endif
687
688	!
689	!-- Check topography for consistency with model domain. Therefore, use
690	!-- maximum and minium topography-top indices. Note, minimum topography top
691	!-- index is already calculated.
692	IF ( TRIM( topography ) /= 'flat' ) THEN
693	#if defined( __parallel )
694	CALL MPI_ALLREDUCE( MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
695	nzb_local_max, 1, MPI_INTEGER, MPI_MAX, comm2d, ierr )
696	#else
697	nzb_local_max = MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
698	#endif
699	nzb_local_min = topo_min_level
700	!
701	!-- Consistency checks
702	IF ( nzb_local_min < 0 .OR. nzb_local_max > nz + 1 ) THEN
703	WRITE( message_string, * ) 'nzb_local values are outside the', &
704	' model domain', &
705	'&MINVAL( nzb_local ) = ', nzb_local_min, &
706	'&MAXVAL( nzb_local ) = ', nzb_local_max
707	CALL message( 'init_grid', 'PA0210', 1, 2, 0, 6, 0 )
708	ENDIF
709	ENDIF
710	!
711	!-- Define vertical gridpoint from (or to) which on the usual finite difference
712	!-- form (which does not use surface fluxes) is applied
713	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
714	nzb_diff = nzb + 2
715	ELSE
716	nzb_diff = nzb + 1
717	ENDIF
718
719	IF ( TRIM( topography ) /= 'flat' ) THEN
720	!
721	!-- Allocate and set the arrays containing the topography height (for output
722	!-- reasons only).
723	IF ( nxr == nx .AND. nyn /= ny ) THEN
724	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn), &
725	zw_w_inner(nxl:nxr+1,nys:nyn) )
726	ELSEIF ( nxr /= nx .AND. nyn == ny ) THEN
727	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn+1), &
728	zw_w_inner(nxl:nxr,nys:nyn+1) )
729	ELSEIF ( nxr == nx .AND. nyn == ny ) THEN
730	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn+1), &
731	zw_w_inner(nxl:nxr+1,nys:nyn+1) )
732	ELSE
733	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn), &
734	zw_w_inner(nxl:nxr,nys:nyn) )
735	ENDIF
736
737	zu_s_inner = 0.0_wp
738	zw_w_inner = 0.0_wp
739	!
740	!-- Determine local topography height on scalar and w-grid. Note, setting
741	!-- lateral boundary values is not necessary, realized via wall_flags_static_0
742	!-- array. Further, please note that loop bounds are different from
743	!-- nxl to nxr and nys to nyn on south and right model boundary, hence,
744	!-- use intrinsic lbound and ubound functions to infer array bounds.
745	DO i = LBOUND(zu_s_inner, 1), UBOUND(zu_s_inner, 1)
746	DO j = LBOUND(zu_s_inner, 2), UBOUND(zu_s_inner, 2)
747	!
748	!-- Topography height on scalar grid. Therefore, determine index of
749	!-- upward-facing surface element on scalar grid.
750	zu_s_inner(i,j) = zu(topo_top_ind(j,i,0))
751	!
752	!-- Topography height on w grid. Therefore, determine index of
753	!-- upward-facing surface element on w grid.
754	zw_w_inner(i,j) = zw(topo_top_ind(j,i,3))
755	ENDDO
756	ENDDO
757	ENDIF
758
759	#if defined( __parallel )
760	!
761	!-- Vertical nesting: communicate vertical grid level arrays between fine and
762	!-- coarse grid
763	IF ( vnested ) CALL vnest_init_grid
764	#endif
765
766	END SUBROUTINE init_grid
767
768
769	! Description:
770	! -----------------------------------------------------------------------------!
771	!> Calculation of the stretching factor through an iterative method. Ideas were
772	!> taken from the paper "Regional stretched grid generation and its application
773	!> to the NCAR RegCM (1999)". Normally, no analytic solution exists because the
774	!> system of equations has two variables (r,l) but four requirements
775	!> (l=integer, r=[0,88;1,2], Eq(6), Eq(5) starting from index j=1) which
776	!> results into an overdetermined system.
777	!------------------------------------------------------------------------------!
778	SUBROUTINE calculate_stretching_factor( number_end )
779
780	USE control_parameters, &
781	ONLY: dz, dz_stretch_factor_array, &
782	dz_stretch_level_end, dz_stretch_level_start, message_string
783
784	USE kinds
785
786	IMPLICIT NONE
787
788	INTEGER(iwp) :: iterations !< number of iterations until stretch_factor_lower/upper_limit is reached
789	INTEGER(iwp) :: l_rounded !< after l_rounded grid levels dz(n) is strechted to dz(n+1) with stretch_factor_2
790	INTEGER(iwp) :: n !< loop variable for stretching
791
792	INTEGER(iwp), INTENT(IN) :: number_end !< number of user-specified end levels for stretching
793
794	REAL(wp) :: delta_l !< absolute difference between l and l_rounded
795	REAL(wp) :: delta_stretch_factor !< absolute difference between stretch_factor_1 and stretch_factor_2
796	REAL(wp) :: delta_total_new !< sum of delta_l and delta_stretch_factor for the next iteration (should be as small as possible)
797	REAL(wp) :: delta_total_old !< sum of delta_l and delta_stretch_factor for the last iteration
798	REAL(wp) :: distance !< distance between dz_stretch_level_start and dz_stretch_level_end (stretching region)
799	REAL(wp) :: l !< value that fulfil Eq. (5) in the paper mentioned above together with stretch_factor_1 exactly
800	REAL(wp) :: numerator !< numerator of the quotient
801	REAL(wp) :: stretch_factor_1 !< stretching factor that fulfil Eq. (5) togehter with l exactly
802	REAL(wp) :: stretch_factor_2 !< stretching factor that fulfil Eq. (6) togehter with l_rounded exactly
803
804	REAL(wp) :: dz_stretch_factor_array_2(9) = 1.08_wp !< Array that contains all stretch_factor_2 that belongs to stretch_factor_1
805
806	REAL(wp), PARAMETER :: stretch_factor_interval = 1.0E-06_wp !< interval for sampling possible stretching factors
807	REAL(wp), PARAMETER :: stretch_factor_lower_limit = 0.88_wp !< lowest possible stretching factor
808	REAL(wp), PARAMETER :: stretch_factor_upper_limit = 1.12_wp !< highest possible stretching factor
809
810
811	l = 0
812	DO n = 1, number_end
813
814	iterations = 1
815	stretch_factor_1 = 1.0_wp
816	stretch_factor_2 = 1.0_wp
817	delta_total_old = 1.0_wp
818
819	!
820	!-- First branch for stretching from rough to fine
821	IF ( dz(n) > dz(n+1) ) THEN
822	DO WHILE ( stretch_factor_1 >= stretch_factor_lower_limit )
823
824	stretch_factor_1 = 1.0_wp - iterations * stretch_factor_interval
825	distance = ABS( dz_stretch_level_end(n) - &
826	dz_stretch_level_start(n) )
827	numerator = distance*stretch_factor_1/dz(n) + &
828	stretch_factor_1 - distance/dz(n)
829
830	IF ( numerator > 0.0_wp ) THEN
831	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0_wp
832	l_rounded = NINT( l )
833	delta_l = ABS( l_rounded - l ) / l
834	ENDIF
835
836	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
837
838	delta_stretch_factor = ABS( stretch_factor_1 - &
839	stretch_factor_2 ) / &
840	stretch_factor_2
841
842	delta_total_new = delta_l + delta_stretch_factor
843
844	!
845	!-- stretch_factor_1 is taken to guarantee that the stretching
846	!-- procedure ends as close as possible to dz_stretch_level_end.
847	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
848	!-- equal to dz(n+1) after l_rounded grid levels.
849	IF (delta_total_new < delta_total_old) THEN
850	dz_stretch_factor_array(n) = stretch_factor_1
851	dz_stretch_factor_array_2(n) = stretch_factor_2
852	delta_total_old = delta_total_new
853	ENDIF
854
855	iterations = iterations + 1
856
857	ENDDO
858
859	!
860	!-- Second branch for stretching from fine to rough
861	ELSEIF ( dz(n) < dz(n+1) ) THEN
862	DO WHILE ( stretch_factor_1 <= stretch_factor_upper_limit )
863
864	stretch_factor_1 = 1.0_wp + iterations * stretch_factor_interval
865	distance = ABS( dz_stretch_level_end(n) - &
866	dz_stretch_level_start(n) )
867	numerator = distance*stretch_factor_1/dz(n) + &
868	stretch_factor_1 - distance/dz(n)
869
870	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0_wp
871	l_rounded = NINT( l )
872	delta_l = ABS( l_rounded - l ) / l
873
874	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
875
876	delta_stretch_factor = ABS( stretch_factor_1 - &
877	stretch_factor_2 ) / &
878	stretch_factor_2
879
880	delta_total_new = delta_l + delta_stretch_factor
881
882	!
883	!-- stretch_factor_1 is taken to guarantee that the stretching
884	!-- procedure ends as close as possible to dz_stretch_level_end.
885	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
886	!-- equal to dz(n+1) after l_rounded grid levels.
887	IF (delta_total_new < delta_total_old) THEN
888	dz_stretch_factor_array(n) = stretch_factor_1
889	dz_stretch_factor_array_2(n) = stretch_factor_2
890	delta_total_old = delta_total_new
891	ENDIF
892
893	iterations = iterations + 1
894	ENDDO
895
896	ELSE
897	message_string= 'Two adjacent values of dz must be different'
898	CALL message( 'init_grid', 'PA0228', 1, 2, 0, 6, 0 )
899
900	ENDIF
901
902	!
903	!-- Check if also the second stretching factor fits into the allowed
904	!-- interval. If not, print a warning for the user.
905	IF ( dz_stretch_factor_array_2(n) < stretch_factor_lower_limit .OR. &
906	dz_stretch_factor_array_2(n) > stretch_factor_upper_limit ) THEN
907	WRITE( message_string, * ) 'stretch_factor_2 = ', &
908	dz_stretch_factor_array_2(n), ' which is',&
909	' responsible for exactly reaching& dz =',&
910	dz(n+1), 'after a specific amount of', &
911	' grid levels& exceeds the upper', &
912	' limit =', stretch_factor_upper_limit, &
913	' &or lower limit = ', &
914	stretch_factor_lower_limit
915	CALL message( 'init_grid', 'PA0499', 0, 1, 0, 6, 0 )
916
917	ENDIF
918	ENDDO
919
920	END SUBROUTINE calculate_stretching_factor
921
922
923	! Description:
924	! -----------------------------------------------------------------------------!
925	!> Set temporary topography flags and reference buildings on top of underlying
926	!> orography.
927	!------------------------------------------------------------------------------!
928	SUBROUTINE process_topography( topo_3d )
929
930	USE arrays_3d, &
931	ONLY: zu, zw
932
933	USE control_parameters, &
934	ONLY: bc_lr_cyc, bc_ns_cyc, message_string, ocean_mode
935
936	USE indices, &
937	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
938	nzt
939
940	USE netcdf_data_input_mod, &
941	ONLY: buildings_f, building_id_f, building_type_f, input_pids_static, &
942	terrain_height_f
943
944	USE kinds
945
946	USE pegrid
947
948	IMPLICIT NONE
949
950	INTEGER(iwp) :: i !< running index along x-direction
951	INTEGER(iwp) :: j !< running index along y-direction
952	INTEGER(iwp) :: k !< running index along z-direction with respect to numeric grid
953	INTEGER(iwp) :: k2 !< running index along z-direction with respect to netcdf grid
954	INTEGER(iwp) :: nr !< index variable indication maximum terrain height for respective building ID
955	INTEGER(iwp) :: num_build !< counter for number of buildings
956	INTEGER(iwp) :: topo_top_index !< orography top index, used to map 3D buildings onto terrain
957
958	#if defined( __parallel )
959	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displace_dum !< displacements of start addresses, used for MPI_ALLGATHERV
960	#endif
961	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids !< building IDs on entire model domain
962	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final !< building IDs on entire model domain, multiple occurences are sorted out
963	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final_tmp !< temporary array used for resizing
964	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l !< building IDs on local subdomain
965	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l_tmp !< temporary array used to resize array of building IDs
966
967	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings !< number of buildings with different ID on entire model domain
968	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings_l !< number of buildings with different ID on local subdomain
969
970	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< input array for 3D topography and dummy array for setting "outer"-flags
971
972	REAL(wp) :: ocean_offset !< offset to consider inverse vertical coordinate at topography definition
973	REAL(wp) :: oro_min = 0.0_wp !< minimum terrain height in entire model domain, used to reference terrain to zero
974	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max !< maximum terrain height occupied by an building with certain id
975	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max_l !< maximum terrain height occupied by an building with certain id, on local subdomain
976
977	!
978	!-- Reference lowest terrain height to zero. In case the minimum terrain height
979	!-- is non-zero, all grid points of the lower vertical grid levels might be
980	!-- entirely below the surface, meaning a waste of computational resources.
981	!-- In order to avoid this, remove the lowest terrain height. Please note,
982	!-- in case of a nested run, the global minimum from all parent and childs
983	!-- need to be remove to avoid steep edges at the child-domain boundaries.
984	IF ( input_pids_static ) THEN
985
986	#if defined( __parallel )
987	CALL MPI_ALLREDUCE( MINVAL( terrain_height_f%var ), oro_min, 1, &
988	MPI_REAL, MPI_MIN, MPI_COMM_WORLD, ierr )
989	#else
990	oro_min = MINVAL( terrain_height_f%var )
991	#endif
992	terrain_height_f%var = terrain_height_f%var - oro_min
993	!
994	!-- Give an informative message that terrain height is referenced to zero
995	IF ( oro_min > 0.0_wp ) THEN
996	WRITE( message_string, * ) 'Terrain height was internally shifted '//&
997	'downwards by ', oro_min, 'meter(s) to save ' // &
998	'computational resources.'
999	CALL message( 'init_grid', 'PA0505', 0, 0, 0, 6, 0 )
1000	ENDIF
1001	ENDIF
1002
1003	!
1004	!-- In the following, buildings and orography are further preprocessed
1005	!-- before they are mapped on the LES grid.
1006	!-- Buildings are mapped on top of the orography by maintaining the roof
1007	!-- shape of the building. This can be achieved by referencing building on
1008	!-- top of the maximum terrain height within the area occupied by the
1009	!-- respective building. As buildings and terrain height are defined PE-wise,
1010	!-- parallelization of this referencing is required (a building can be
1011	!-- distributed between different PEs).
1012	!-- In a first step, determine the number of buildings with different
1013	!-- building id on each PE. In a next step, all building ids are gathered
1014	!-- into one array which is present to all PEs. For each building ID,
1015	!-- the maximum terrain height occupied by the respective building is
1016	!-- computed and distributed to each PE.
1017	!-- Finally, for each building id and its respective reference orography,
1018	!-- builidings are mapped on top.
1019	!--
1020	!-- First, pre-set topography flags, bit 1 indicates orography, bit 2
1021	!-- buildings
1022	!-- classify the respective surfaces.
1023	topo_3d = IBSET( topo_3d, 0 )
1024	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1025	!
1026	!-- In order to map topography on PALM grid also in case of ocean simulations,
1027	!-- pre-calculate an offset value.
1028	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1029	!
1030	!-- Reference buildings on top of orography. This is not necessary
1031	!-- if topography is read from ASCII file as no distinction between buildings
1032	!-- and terrain height can be made. Moreover, this is also not necessary if
1033	!-- urban-surface and land-surface model are used at the same time.
1034	IF ( input_pids_static ) THEN
1035
1036	IF ( buildings_f%from_file ) THEN
1037	num_buildings_l = 0
1038	num_buildings = 0
1039	!
1040	!-- Allocate at least one element for building ids and give it an inital
1041	!-- negative value that will be overwritten later. This, however, is
1042	!-- necessary in case there all IDs in the model domain are fill values.
1043	ALLOCATE( build_ids_l(1) )
1044	build_ids_l = -1
1045	DO i = nxl, nxr
1046	DO j = nys, nyn
1047	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1048	IF ( num_buildings_l(myid) > 0 ) THEN
1049	IF ( ANY( building_id_f%var(j,i) == build_ids_l ) ) &
1050	THEN
1051	CYCLE
1052	ELSE
1053	num_buildings_l(myid) = num_buildings_l(myid) + 1
1054	!
1055	!-- Resize array with different local building ids
1056	ALLOCATE( build_ids_l_tmp(1:SIZE(build_ids_l)) )
1057	build_ids_l_tmp = build_ids_l
1058	DEALLOCATE( build_ids_l )
1059	ALLOCATE( build_ids_l(1:num_buildings_l(myid)) )
1060	build_ids_l(1:num_buildings_l(myid)-1) = &
1061	build_ids_l_tmp(1:num_buildings_l(myid)-1)
1062	build_ids_l(num_buildings_l(myid)) = building_id_f%var(j,i)
1063	DEALLOCATE( build_ids_l_tmp )
1064	ENDIF
1065	!
1066	!-- First occuring building id on PE
1067	ELSE
1068	num_buildings_l(myid) = num_buildings_l(myid) + 1
1069	build_ids_l(1) = building_id_f%var(j,i)
1070	ENDIF
1071	ENDIF
1072	ENDDO
1073	ENDDO
1074	!
1075	!-- Determine number of different building ids for the entire domain
1076	#if defined( __parallel )
1077	CALL MPI_ALLREDUCE( num_buildings_l, num_buildings, numprocs, &
1078	MPI_INTEGER, MPI_SUM, comm2d, ierr )
1079	#else
1080	num_buildings = num_buildings_l
1081	#endif
1082	!
1083	!-- Gather all buildings ids on each PEs.
1084	!-- First, allocate array encompassing all building ids in model domain.
1085	ALLOCATE( build_ids(1:SUM(num_buildings)) )
1086	#if defined( __parallel )
1087	!
1088	!-- Allocate array for displacements.
1089	!-- As each PE may has a different number of buildings, so that
1090	!-- the block sizes send by each PE may not be equal. Hence,
1091	!-- information about the respective displacement is required, indicating
1092	!-- the respective adress where each MPI-task writes into the receive
1093	!-- buffer array
1094	ALLOCATE( displace_dum(0:numprocs-1) )
1095	displace_dum(0) = 0
1096	DO i = 1, numprocs-1
1097	displace_dum(i) = displace_dum(i-1) + num_buildings(i-1)
1098	ENDDO
1099
1100	CALL MPI_ALLGATHERV( build_ids_l(1:num_buildings_l(myid)), &
1101	num_buildings(myid), &
1102	MPI_INTEGER, &
1103	build_ids, &
1104	num_buildings, &
1105	displace_dum, &
1106	MPI_INTEGER, &
1107	comm2d, ierr )
1108
1109	DEALLOCATE( displace_dum )
1110
1111	#else
1112	build_ids = build_ids_l
1113	#endif
1114
1115	!
1116	!-- Note, in parallel mode building ids can occure mutliple times, as
1117	!-- each PE has send its own ids. Therefore, sort out building ids which
1118	!-- appear more than one time.
1119	num_build = 0
1120	DO nr = 1, SIZE(build_ids)
1121
1122	IF ( ALLOCATED(build_ids_final) ) THEN
1123	IF ( ANY( build_ids(nr) == build_ids_final ) ) THEN
1124	CYCLE
1125	ELSE
1126	num_build = num_build + 1
1127	!
1128	!-- Resize
1129	ALLOCATE( build_ids_final_tmp(1:num_build) )
1130	build_ids_final_tmp(1:num_build-1) = build_ids_final(1:num_build-1)
1131	DEALLOCATE( build_ids_final )
1132	ALLOCATE( build_ids_final(1:num_build) )
1133	build_ids_final(1:num_build-1) = build_ids_final_tmp(1:num_build-1)
1134	build_ids_final(num_build) = build_ids(nr)
1135	DEALLOCATE( build_ids_final_tmp )
1136	ENDIF
1137	ELSE
1138	num_build = num_build + 1
1139	ALLOCATE( build_ids_final(1:num_build) )
1140	build_ids_final(num_build) = build_ids(nr)
1141	ENDIF
1142	ENDDO
1143
1144	!
1145	!-- Determine maximumum terrain height occupied by the respective
1146	!-- building and temporalily store on oro_max
1147	ALLOCATE( oro_max_l(1:SIZE(build_ids_final)) )
1148	ALLOCATE( oro_max(1:SIZE(build_ids_final)) )
1149	oro_max_l = 0.0_wp
1150
1151	DO nr = 1, SIZE(build_ids_final)
1152	oro_max_l(nr) = MAXVAL( &
1153	MERGE( terrain_height_f%var(nys:nyn,nxl:nxr), &
1154	0.0_wp, &
1155	building_id_f%var(nys:nyn,nxl:nxr) == &
1156	build_ids_final(nr) ) )
1157	ENDDO
1158
1159	#if defined( __parallel )
1160	IF ( SIZE(build_ids_final) >= 1 ) THEN
1161	CALL MPI_ALLREDUCE( oro_max_l, oro_max, SIZE( oro_max ), MPI_REAL,&
1162	MPI_MAX, comm2d, ierr )
1163	ENDIF
1164	#else
1165	oro_max = oro_max_l
1166	#endif
1167	!
1168	!-- Finally, determine discrete grid height of maximum orography occupied
1169	!-- by a building. Use all-or-nothing approach, i.e. if terrain
1170	!-- exceeds the scalar level the grid box is fully terrain and the
1171	!-- maximum terrain is set to the zw level.
1172	!-- terrain or
1173	oro_max_l = 0.0
1174	DO nr = 1, SIZE(build_ids_final)
1175	DO k = nzb, nzt
1176	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1177	oro_max_l(nr) = zw(k) - ocean_offset
1178	ENDDO
1179	oro_max(nr) = oro_max_l(nr)
1180	ENDDO
1181	ENDIF
1182	!
1183	!-- Allocate array for storing terrain height under buildings
1184	IF ( buildings_f%from_file ) THEN
1185	ALLOCATE( buildings_f%oro_max(nysg:nyng,nxlg:nxrg) )
1186	buildings_f%oro_max = buildings_f%fill1
1187	END IF
1188	!
1189	!-- Map orography as well as buildings onto grid.
1190	DO i = nxl, nxr
1191	DO j = nys, nyn
1192	topo_top_index = 0
1193	!
1194	!-- Obtain index in global building_id array
1195	IF ( buildings_f%from_file ) THEN
1196	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1197	!
1198	!-- Determine index where maximum terrain height occupied by
1199	!-- the respective building height is stored.
1200	nr = MINLOC( ABS( build_ids_final - &
1201	building_id_f%var(j,i) ), DIM = 1 )
1202	!
1203	!-- Save grid-indexed oro_max
1204	buildings_f%oro_max(j,i) = oro_max(nr)
1205	ENDIF
1206	ENDIF
1207	DO k = nzb, nzt
1208	!
1209	!-- In a first step, if grid point is below or equal the given
1210	!-- terrain height, grid point is flagged to be of type natural.
1211	!-- Please note, in case there is also a building which is lower
1212	!-- than the vertical grid spacing, initialization of surface
1213	!-- attributes will not be correct as given surface information
1214	!-- will not be in accordance to the classified grid points.
1215	!-- Hence, in this case, also a building flag.
1216	IF ( zu(k) - ocean_offset <= terrain_height_f%var(j,i) ) THEN
1217	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1218	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1219	topo_top_index = k ! topo_top_index + 1
1220	ENDIF
1221	!
1222	!-- Set building grid points. Here, only consider 2D buildings.
1223	!-- 3D buildings require separate treatment.
1224	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1225	!
1226	!-- Fill-up the terrain to the level of maximum orography
1227	!-- within the building-covered area.
1228	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1229	!
1230	!-- Note, oro_max is always on zw level
1231	IF ( zu(k) - ocean_offset < oro_max(nr) ) THEN
1232	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1233	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1234	ELSEIF ( zu(k) - ocean_offset <= &
1235	oro_max(nr) + buildings_f%var_2d(j,i) ) THEN
1236	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1237	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1238	ENDIF
1239	ENDIF
1240	ENDIF
1241	ENDDO
1242	!
1243	!-- Special treatment for non grid-resolved buildings. This case,
1244	!-- the uppermost terrain grid point is flagged as building as well
1245	!-- well, even though no building exists at all. However, the
1246	!-- surface element will be identified as urban-surface and the
1247	!-- input data provided by the drivers is consistent to the surface
1248	!-- classification. Else, all non grid-resolved buildings would vanish
1249	!-- and identified as terrain grid points, which, however, won't be
1250	!-- consistent with the input data.
1251	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1252	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1253	DO k = nzb, nzt
1254	IF( zw(k) - ocean_offset == oro_max(nr) ) THEN
1255	IF ( buildings_f%var_2d(j,i) <= zu(k+1) - zw(k) ) THEN
1256	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1257	ENDIF
1258	ENDIF
1259	ENDDO
1260	ENDIF
1261	ENDIF
1262	!
1263	!-- Map 3D buildings onto terrain height.
1264	!-- In case of any slopes, map building on top of maximum terrain
1265	!-- height covered by the building. In other words, extend
1266	!-- building down to the respective local terrain-surface height.
1267	IF ( buildings_f%from_file .AND. buildings_f%lod == 2 ) THEN
1268	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1269	!
1270	!-- Extend building down to the terrain surface, i.e. fill-up
1271	!-- surface irregularities below a building. Note, oro_max
1272	!-- is already a discrete height according to the all-or-nothing
1273	!-- approach, i.e. grid box is either topography or atmosphere,
1274	!-- terrain top is defined at upper bound of the grid box.
1275	!-- Hence, check for zw in this case.
1276	!-- Note, do this only for buildings which are surface mounted,
1277	!-- i.e. building types 1-6. Below bridges, which are represented
1278	!-- exclusively by building type 7, terrain shape should be
1279	!-- maintained.
1280	IF ( building_type_f%from_file ) THEN
1281	IF ( building_type_f%var(j,i) /= 7 ) THEN
1282	DO k = topo_top_index + 1, nzt + 1
1283	IF ( zu(k) - ocean_offset <= oro_max(nr) ) THEN
1284	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1285	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1286	ENDIF
1287	ENDDO
1288	!
1289	!-- After surface irregularities are smoothen, determine
1290	!-- lower start index where building starts.
1291	DO k = nzb, nzt
1292	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1293	topo_top_index = k
1294	ENDDO
1295	ENDIF
1296	ENDIF
1297	!
1298	!-- Finally, map building on top.
1299	k2 = 0
1300	DO k = topo_top_index, nzt + 1
1301	IF ( k2 <= buildings_f%nz-1 ) THEN
1302	IF ( buildings_f%var_3d(k2,j,i) == 1 ) THEN
1303	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1304	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1305	ENDIF
1306	ENDIF
1307	k2 = k2 + 1
1308	ENDDO
1309	ENDIF
1310	ENDIF
1311	ENDDO
1312	ENDDO
1313	!
1314	!-- Horizontal exchange the oro_max array, which is required to for
1315	!-- initialization of building-surface properties.
1316	IF ( ALLOCATED( buildings_f%oro_max ) ) THEN
1317	CALL exchange_horiz_2d( buildings_f%oro_max(:,:), nbgp )
1318	ENDIF
1319	!
1320	!-- Deallocate temporary arrays required for processing and reading data
1321	IF ( ALLOCATED( oro_max ) ) DEALLOCATE( oro_max )
1322	IF ( ALLOCATED( oro_max_l ) ) DEALLOCATE( oro_max_l )
1323	IF ( ALLOCATED( build_ids_final ) ) DEALLOCATE( build_ids_final )
1324	!
1325	!-- Topography input via ASCII format.
1326	ELSE
1327	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1328	!
1329	!-- Initialize topography bit 0 (indicates obstacle) everywhere to zero
1330	!-- and clear all grid points at nzb, where alway a surface is defined.
1331	!-- Further, set also bit 1 (indicates terrain) at nzb, which is further
1332	!-- used for masked data output and further processing. Note, in the
1333	!-- ASCII case no distinction is made between buildings and terrain,
1334	!-- so that setting of bit 1 and 2 at the same time has no effect.
1335	topo_3d = IBSET( topo_3d, 0 )
1336	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1337	topo_3d(nzb,:,:) = IBSET( topo_3d(nzb,:,:), 1 )
1338	DO i = nxl, nxr
1339	DO j = nys, nyn
1340	DO k = nzb, nzt
1341	!
1342	!-- Flag topography for all grid points which are below
1343	!-- the local topography height.
1344	!-- Note, each topography is flagged as building.
1345	IF ( zu(k) - ocean_offset <= buildings_f%var_2d(j,i) ) THEN
1346	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1347	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 ) !indicates building
1348	ENDIF
1349	ENDDO
1350	ENDDO
1351	ENDDO
1352	ENDIF
1353
1354	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1355
1356	IF ( .NOT. bc_ns_cyc ) THEN
1357	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1358	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1359	ENDIF
1360
1361	IF ( .NOT. bc_lr_cyc ) THEN
1362	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1363	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1364	ENDIF
1365
1366	END SUBROUTINE process_topography
1367
1368
1369	! Description:
1370	! -----------------------------------------------------------------------------!
1371	!> Filter topography, i.e. fill holes resolved by only one grid point.
1372	!> Such holes are suspected to lead to velocity blow-ups as continuity
1373	!> equation on discrete grid cannot be fulfilled in such case.
1374	!------------------------------------------------------------------------------!
1375	SUBROUTINE filter_topography( topo_3d )
1376
1377	USE control_parameters, &
1378	ONLY: bc_lr_cyc, bc_ns_cyc, message_string
1379
1380	USE indices, &
1381	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt
1382
1383	USE netcdf_data_input_mod, &
1384	ONLY: building_id_f, building_type_f
1385
1386	USE pegrid
1387
1388	IMPLICIT NONE
1389
1390	LOGICAL :: filled = .FALSE. !< flag indicating if holes were filled
1391
1392	INTEGER(iwp) :: i !< running index along x-direction
1393	INTEGER(iwp) :: j !< running index along y-direction
1394	INTEGER(iwp) :: k !< running index along z-direction
1395	INTEGER(iwp) :: num_hole !< number of holes (in topography) resolved by only one grid point
1396	INTEGER(iwp) :: num_hole_l !< number of holes (in topography) resolved by only one grid point on local PE
1397	INTEGER(iwp) :: num_wall !< number of surrounding vertical walls for a single grid point
1398
1399	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo_tmp !< temporary 3D-topography used to fill holes
1400	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< 3D-topography array merging buildings and orography
1401	!
1402	!-- Before checking for holes, set lateral boundary conditions for
1403	!-- topography. After hole-filling, boundary conditions must be set again.
1404	!-- Several iterations are performed, in order to fill holes which might
1405	!-- emerge by the filling-algorithm itself.
1406	ALLOCATE( topo_tmp(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
1407	topo_tmp = 0
1408
1409	num_hole = 99999
1410	DO WHILE ( num_hole > 0 )
1411
1412	num_hole = 0
1413	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1414	!
1415	!-- Exchange also building ID and type. Note, building_type is an one-byte
1416	!-- variable.
1417	IF ( building_id_f%from_file ) &
1418	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1419	IF ( building_type_f%from_file ) &
1420	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1421
1422	topo_tmp = topo_3d
1423	!
1424	!-- In case of non-cyclic lateral boundaries, assume lateral boundary to be
1425	!-- a solid wall. Thus, intermediate spaces of one grid point between
1426	!-- boundary and some topographic structure will be filled.
1427	IF ( .NOT. bc_ns_cyc ) THEN
1428	IF ( nys == 0 ) topo_tmp(:,-1,:) = IBCLR( topo_tmp(:,0,:), 0 )
1429	IF ( nyn == ny ) topo_tmp(:,ny+1,:) = IBCLR( topo_tmp(:,ny,:), 0 )
1430	ENDIF
1431
1432	IF ( .NOT. bc_lr_cyc ) THEN
1433	IF ( nxl == 0 ) topo_tmp(:,:,-1) = IBCLR( topo_tmp(:,:,0), 0 )
1434	IF ( nxr == nx ) topo_tmp(:,:,nx+1) = IBCLR( topo_tmp(:,:,nx), 0 )
1435	ENDIF
1436
1437	num_hole_l = 0
1438	DO i = nxl, nxr
1439	DO j = nys, nyn
1440	DO k = nzb+1, nzt
1441	IF ( BTEST( topo_tmp(k,j,i), 0 ) ) THEN
1442	num_wall = 0
1443	IF ( .NOT. BTEST( topo_tmp(k,j-1,i), 0 ) ) &
1444	num_wall = num_wall + 1
1445	IF ( .NOT. BTEST( topo_tmp(k,j+1,i), 0 ) ) &
1446	num_wall = num_wall + 1
1447	IF ( .NOT. BTEST( topo_tmp(k,j,i-1), 0 ) ) &
1448	num_wall = num_wall + 1
1449	IF ( .NOT. BTEST( topo_tmp(k,j,i+1), 0 ) ) &
1450	num_wall = num_wall + 1
1451	IF ( .NOT. BTEST( topo_tmp(k-1,j,i), 0 ) ) &
1452	num_wall = num_wall + 1
1453	IF ( .NOT. BTEST( topo_tmp(k+1,j,i), 0 ) ) &
1454	num_wall = num_wall + 1
1455
1456	IF ( num_wall >= 4 ) THEN
1457	num_hole_l = num_hole_l + 1
1458	!
1459	!-- Clear flag 0 and set special flag ( bit 4) to indicate
1460	!-- that new topography point is a result of filtering process.
1461	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1462	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 4 )
1463	!
1464	!-- If filled grid point is occupied by a building, classify
1465	!-- it as building grid point.
1466	IF ( building_type_f%from_file ) THEN
1467	IF ( building_type_f%var(j,i) /= &
1468	building_type_f%fill .OR. &
1469	building_type_f%var(j+1,i) /= &
1470	building_type_f%fill .OR. &
1471	building_type_f%var(j-1,i) /= &
1472	building_type_f%fill .OR. &
1473	building_type_f%var(j,i+1) /= &
1474	building_type_f%fill .OR. &
1475	building_type_f%var(j,i-1) /= &
1476	building_type_f%fill ) THEN
1477	!
1478	!-- Set flag indicating building surfaces
1479	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1480	!
1481	!-- Set building_type and ID at this position if not
1482	!-- already set. This is required for proper
1483	!-- initialization of urban-surface energy balance
1484	!-- solver.
1485	IF ( building_type_f%var(j,i) == &
1486	building_type_f%fill ) THEN
1487
1488	IF ( building_type_f%var(j+1,i) /= &
1489	building_type_f%fill ) THEN
1490	building_type_f%var(j,i) = &
1491	building_type_f%var(j+1,i)
1492	building_id_f%var(j,i) = &
1493	building_id_f%var(j+1,i)
1494	ELSEIF ( building_type_f%var(j-1,i) /= &
1495	building_type_f%fill ) THEN
1496	building_type_f%var(j,i) = &
1497	building_type_f%var(j-1,i)
1498	building_id_f%var(j,i) = &
1499	building_id_f%var(j-1,i)
1500	ELSEIF ( building_type_f%var(j,i+1) /= &
1501	building_type_f%fill ) THEN
1502	building_type_f%var(j,i) = &
1503	building_type_f%var(j,i+1)
1504	building_id_f%var(j,i) = &
1505	building_id_f%var(j,i+1)
1506	ELSEIF ( building_type_f%var(j,i-1) /= &
1507	building_type_f%fill ) THEN
1508	building_type_f%var(j,i) = &
1509	building_type_f%var(j,i-1)
1510	building_id_f%var(j,i) = &
1511	building_id_f%var(j,i-1)
1512	ENDIF
1513	ENDIF
1514	ENDIF
1515	ENDIF
1516	!
1517	!-- If filled grid point is already classified as building
1518	!-- everything is fine, else classify this grid point as
1519	!-- natural type grid point. This case, values for the
1520	!-- surface type are already set.
1521	IF ( .NOT. BTEST( topo_3d(k,j,i), 2 ) ) THEN
1522	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1523	ENDIF
1524	ENDIF
1525	ENDIF
1526	ENDDO
1527	ENDDO
1528	ENDDO
1529	!
1530	!-- Count the total number of holes, required for informative message.
1531	#if defined( __parallel )
1532	CALL MPI_ALLREDUCE( num_hole_l, num_hole, 1, MPI_INTEGER, MPI_SUM, &
1533	comm2d, ierr )
1534	#else
1535	num_hole = num_hole_l
1536	#endif
1537	IF ( num_hole > 0 .AND. .NOT. filled ) filled = .TRUE.
1538
1539	ENDDO
1540	!
1541	!-- Create an informative message if any holes were filled.
1542	IF ( filled ) THEN
1543	WRITE( message_string, * ) 'Topography was filtered, i.e. holes ' // &
1544	'resolved by only one grid point ' // &
1545	'were filled during initialization.'
1546	CALL message( 'init_grid', 'PA0430', 0, 0, 0, 6, 0 )
1547	ENDIF
1548
1549	DEALLOCATE( topo_tmp )
1550	!
1551	!-- Finally, exchange topo_3d array again and if necessary set Neumann boundary
1552	!-- condition in case of non-cyclic lateral boundaries.
1553	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1554
1555	IF ( .NOT. bc_ns_cyc ) THEN
1556	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1557	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1558	ENDIF
1559
1560	IF ( .NOT. bc_lr_cyc ) THEN
1561	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1562	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1563	ENDIF
1564	!
1565	!-- Exchange building ID and type. Note, building_type is an one-byte variable.
1566	IF ( building_id_f%from_file ) &
1567	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1568	IF ( building_type_f%from_file ) &
1569	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1570
1571	END SUBROUTINE filter_topography
1572
1573
1574	! Description:
1575	! -----------------------------------------------------------------------------!
1576	!> Reads topography information from file or sets generic topography. Moreover,
1577	!> all topography-relevant topography arrays are initialized, and grid flags
1578	!> are set.
1579	!------------------------------------------------------------------------------!
1580	SUBROUTINE init_topo( topo )
1581
1582	USE arrays_3d, &
1583	ONLY: zw
1584
1585	USE control_parameters, &
1586	ONLY: bc_lr_cyc, bc_ns_cyc, building_height, building_length_x, &
1587	building_length_y, building_wall_left, building_wall_south, &
1588	canyon_height, canyon_wall_left, canyon_wall_south, &
1589	canyon_width_x, canyon_width_y, dp_level_ind_b, dz, &
1590	message_string, topography, topography_grid_convention, &
1591	tunnel_height, tunnel_length, tunnel_width_x, tunnel_width_y, &
1592	tunnel_wall_depth
1593
1594	USE grid_variables, &
1595	ONLY: dx, dy
1596
1597	USE indices, &
1598	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
1599	nzb, nzt
1600
1601	USE kinds
1602
1603	USE netcdf_data_input_mod, &
1604	ONLY: buildings_f, terrain_height_f
1605
1606	USE pegrid
1607
1608	IMPLICIT NONE
1609
1610	INTEGER(iwp) :: bh !< temporary vertical index of building height
1611	INTEGER(iwp) :: ngp_bx !< grid point number of building size along x
1612	INTEGER(iwp) :: ngp_by !< grid point number of building size along y
1613	INTEGER(iwp) :: index_left_bwall !< index for left building wall
1614	INTEGER(iwp) :: index_right_bwall !< index for right building wall
1615	INTEGER(iwp) :: index_north_bwall !< index for north building wall
1616	INTEGER(iwp) :: index_south_bwall !< index for south building wall
1617	INTEGER(iwp) :: ch !< temporary vertical index for canyon height
1618	INTEGER(iwp) :: ngp_cx !< grid point number of canyon size along x
1619	INTEGER(iwp) :: ngp_cy !< grid point number of canyon size along y
1620	INTEGER(iwp) :: index_left_cwall !< index for left canyon wall
1621	INTEGER(iwp) :: index_right_cwall !< index for right canyon wall
1622	INTEGER(iwp) :: index_north_cwall !< index for north canyon wall
1623	INTEGER(iwp) :: index_south_cwall !< index for south canyon wall
1624	INTEGER(iwp) :: i !< index variable along x
1625	INTEGER(iwp) :: j !< index variable along y
1626	INTEGER(iwp) :: k !< index variable along z
1627	INTEGER(iwp) :: hv_in !< heavyside function to model inner tunnel surface
1628	INTEGER(iwp) :: hv_out !< heavyside function to model outer tunnel surface
1629	INTEGER(iwp) :: txe_out !< end position of outer tunnel wall in x
1630	INTEGER(iwp) :: txs_out !< start position of outer tunnel wall in x
1631	INTEGER(iwp) :: tye_out !< end position of outer tunnel wall in y
1632	INTEGER(iwp) :: tys_out !< start position of outer tunnel wall in y
1633	INTEGER(iwp) :: txe_in !< end position of inner tunnel wall in x
1634	INTEGER(iwp) :: txs_in !< start position of inner tunnel wall in x
1635	INTEGER(iwp) :: tye_in !< end position of inner tunnel wall in y
1636	INTEGER(iwp) :: tys_in !< start position of inner tunnel wall in y
1637	INTEGER(iwp) :: td !< tunnel wall depth
1638	INTEGER(iwp) :: th !< height of outer tunnel wall
1639
1640	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
1641	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
1642	!
1643	!-- Check for correct setting of the namelist parameter topography. If
1644	!-- topography information is read from file but topography = 'flat',
1645	!-- initialization does not work properly.
1646	IF ( ( buildings_f%from_file .OR. terrain_height_f%from_file ) .AND. &
1647	TRIM( topography ) /= 'read_from_file' ) THEN
1648	message_string = 'If topography information is provided (via ' // &
1649	'Netcdf or ASCII input) topography = ' // &
1650	'"read_from_file" is required.'
1651	CALL message( 'init_grid', 'PA0437', 1, 2, 0, 6, 0 )
1652	ENDIF
1653	!
1654	!-- Set outer and inner index arrays for non-flat topography.
1655	!-- Here consistency checks concerning domain size and periodicity are
1656	!-- necessary.
1657	!-- Within this SELECT CASE structure only nzb_local is initialized
1658	!-- individually depending on the chosen topography type, all other index
1659	!-- arrays are initialized further below.
1660	SELECT CASE ( TRIM( topography ) )
1661
1662	CASE ( 'flat' )
1663	!
1664	!-- Initialilize 3D topography array, used later for initializing flags
1665	topo(nzb+1:nzt+1,:,:) = IBSET( topo(nzb+1:nzt+1,:,:), 0 )
1666
1667	CASE ( 'closed_channel' )
1668	!
1669	!-- Initialilize 3D topography array, used later for initializing flags
1670	topo(nzb+1:nzt,:,:) = IBSET( topo(nzb+1:nzt,:,:), 0 )
1671
1672	CASE ( 'single_building' )
1673	!
1674	!-- Single rectangular building, by default centered in the middle of the
1675	!-- total domain
1676	ngp_bx = NINT( building_length_x / dx )
1677	ngp_by = NINT( building_length_y / dy )
1678	bh = MINLOC( ABS( zw - building_height ), 1 ) - 1
1679	IF ( ABS( zw(bh) - building_height ) == &
1680	ABS( zw(bh+1) - building_height ) ) bh = bh + 1
1681	IF ( building_wall_left == 9999999.9_wp ) THEN
1682	building_wall_left = ( nx + 1 - ngp_bx ) / 2 * dx
1683	ENDIF
1684	index_left_bwall = NINT( building_wall_left / dx )
1685	index_right_bwall = index_left_bwall + ngp_bx
1686
1687	IF ( building_wall_south == 9999999.9_wp ) THEN
1688	building_wall_south = ( ny + 1 - ngp_by ) / 2 * dy
1689	ENDIF
1690	index_south_bwall = NINT( building_wall_south / dy )
1691	index_north_bwall = index_south_bwall + ngp_by
1692
1693	!
1694	!-- Building size has to meet some requirements
1695	IF ( ( index_left_bwall < 1 ) .OR. ( index_right_bwall > nx-1 ) .OR. &
1696	( index_right_bwall < index_left_bwall+3 ) .OR. &
1697	( index_south_bwall < 1 ) .OR. ( index_north_bwall > ny-1 ) .OR.&
1698	( index_north_bwall < index_south_bwall+3 ) ) THEN
1699	WRITE( message_string, * ) 'inconsistent building parameters:', &
1700	'&index_left_bwall=', index_left_bwall, &
1701	'index_right_bwall=', index_right_bwall, &
1702	'index_south_bwall=', index_south_bwall, &
1703	'index_north_bwall=', index_north_bwall, &
1704	'nx=', nx, 'ny=', ny
1705	CALL message( 'init_grid', 'PA0203', 1, 2, 0, 6, 0 )
1706	ENDIF
1707
1708	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1709	nzb_local = 0
1710	!
1711	!-- Define the building.
1712	IF ( index_left_bwall <= nxr .AND. index_right_bwall >= nxl .AND. &
1713	index_south_bwall <= nyn .AND. index_north_bwall >= nys ) &
1714	nzb_local(MAX(nys,index_south_bwall):MIN(nyn,index_north_bwall), &
1715	MAX(nxl,index_left_bwall):MIN(nxr,index_right_bwall)) = bh
1716	!
1717	!-- Set bit array on basis of nzb_local
1718	DO i = nxl, nxr
1719	DO j = nys, nyn
1720	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1721	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1722	ENDDO
1723	ENDDO
1724
1725	DEALLOCATE( nzb_local )
1726
1727	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1728	!
1729	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1730	!-- boundary conditions for topography.
1731	IF ( .NOT. bc_ns_cyc ) THEN
1732	IF ( nys == 0 ) THEN
1733	DO i = 1, nbgp
1734	topo(:,nys-i,:) = topo(:,nys,:)
1735	ENDDO
1736	ENDIF
1737	IF ( nyn == ny ) THEN
1738	DO i = 1, nbgp
1739	topo(:,nyn+i,:) = topo(:,nyn,:)
1740	ENDDO
1741	ENDIF
1742	ENDIF
1743	IF ( .NOT. bc_lr_cyc ) THEN
1744	IF ( nxl == 0 ) THEN
1745	DO i = 1, nbgp
1746	topo(:,:,nxl-i) = topo(:,:,nxl)
1747	ENDDO
1748	ENDIF
1749	IF ( nxr == nx ) THEN
1750	DO i = 1, nbgp
1751	topo(:,:,nxr+i) = topo(:,:,nxr)
1752	ENDDO
1753	ENDIF
1754	ENDIF
1755
1756	CASE ( 'single_street_canyon' )
1757	!
1758	!-- Single quasi-2D street canyon of infinite length in x or y direction.
1759	!-- The canyon is centered in the other direction by default.
1760	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1761	!
1762	!-- Street canyon in y direction
1763	ngp_cx = NINT( canyon_width_x / dx )
1764	IF ( canyon_wall_left == 9999999.9_wp ) THEN
1765	canyon_wall_left = ( nx + 1 - ngp_cx ) / 2 * dx
1766	ENDIF
1767	index_left_cwall= NINT( canyon_wall_left / dx )
1768	index_right_cwall= index_left_cwall+ ngp_cx
1769	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1770	!
1771	!-- Street canyon in x direction
1772	ngp_cy = NINT( canyon_width_y / dy )
1773	IF ( canyon_wall_south == 9999999.9_wp ) THEN
1774	canyon_wall_south = ( ny + 1 - ngp_cy ) / 2 * dy
1775	ENDIF
1776	index_south_cwall = NINT( canyon_wall_south / dy )
1777	index_north_cwall = index_south_cwall + ngp_cy
1778
1779	ELSE
1780
1781	message_string = 'no street canyon width given'
1782	CALL message( 'init_grid', 'PA0204', 1, 2, 0, 6, 0 )
1783
1784	ENDIF
1785
1786	ch = MINLOC( ABS( zw - canyon_height ), 1 ) - 1
1787	IF ( ABS( zw(ch) - canyon_height ) == &
1788	ABS( zw(ch+1) - canyon_height ) ) ch = ch + 1
1789	dp_level_ind_b = ch
1790	!
1791	!-- Street canyon size has to meet some requirements
1792	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1793	IF ( ( index_left_cwall< 1 ) .OR. ( index_right_cwall> nx-1 ) .OR.&
1794	( ngp_cx < 3 ) .OR. ( ch < 3 ) ) THEN
1795	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1796	'&index_left_cwall=', index_left_cwall, &
1797	' index_right_cwall=', index_right_cwall, &
1798	' ngp_cx=', ngp_cx, &
1799	' ch=', ch, ' nx=', nx, ' ny=', ny
1800	CALL message( 'init_grid', 'PA0205', 1, 2, 0, 6, 0 )
1801	ENDIF
1802	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1803	IF ( ( index_south_cwall < 1 ) .OR. &
1804	( index_north_cwall > ny-1 ) .OR. ( ngp_cy < 3 ) .OR. &
1805	( ch < 3 ) ) THEN
1806	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1807	'&index_south_cwall=', index_south_cwall, &
1808	' index_north_cwall=', index_north_cwall, &
1809	' ngp_cy=', ngp_cy, &
1810	' ch=', ch, ' nx=', nx, ' ny=', ny
1811	CALL message( 'init_grid', 'PA0206', 1, 2, 0, 6, 0 )
1812	ENDIF
1813	ENDIF
1814	IF ( canyon_width_x /= 9999999.9_wp .AND. &
1815	canyon_width_y /= 9999999.9_wp ) THEN
1816	message_string = 'inconsistent canyon parameters:' // &
1817	'&street canyon can only be oriented' // &
1818	' either in x- or in y-direction'
1819	CALL message( 'init_grid', 'PA0207', 1, 2, 0, 6, 0 )
1820	ENDIF
1821
1822	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1823	nzb_local = ch
1824	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1825	IF ( index_left_cwall<= nxr .AND. index_right_cwall>= nxl ) &
1826	nzb_local(:,MAX(nxl,index_left_cwall+1):MIN(nxr,index_right_cwall-1)) = 0
1827	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1828	IF ( index_south_cwall <= nyn .AND. index_north_cwall >= nys ) &
1829	nzb_local(MAX(nys,index_south_cwall+1):MIN(nyn,index_north_cwall-1),:) = 0
1830	ENDIF
1831	!
1832	!-- Set bit array on basis of nzb_local
1833	DO i = nxl, nxr
1834	DO j = nys, nyn
1835	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1836	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1837	ENDDO
1838	ENDDO
1839	DEALLOCATE( nzb_local )
1840
1841	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1842	!
1843	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1844	!-- boundary conditions for topography.
1845	IF ( .NOT. bc_ns_cyc ) THEN
1846	IF ( nys == 0 ) THEN
1847	DO i = 1, nbgp
1848	topo(:,nys-i,:) = topo(:,nys,:)
1849	ENDDO
1850	ENDIF
1851	IF ( nyn == ny ) THEN
1852	DO i = 1, nbgp
1853	topo(:,nyn+i,:) = topo(:,nyn,:)
1854	ENDDO
1855	ENDIF
1856	ENDIF
1857	IF ( .NOT. bc_lr_cyc ) THEN
1858	IF ( nxl == 0 ) THEN
1859	DO i = 1, nbgp
1860	topo(:,:,nxl-i) = topo(:,:,nxl)
1861	ENDDO
1862	ENDIF
1863	IF ( nxr == nx ) THEN
1864	DO i = 1, nbgp
1865	topo(:,:,nxr+i) = topo(:,:,nxr)
1866	ENDDO
1867	ENDIF
1868	ENDIF
1869
1870	CASE ( 'tunnel' )
1871
1872	!
1873	!-- Tunnel height
1874	IF ( tunnel_height == 9999999.9_wp ) THEN
1875	th = zw( INT( 0.2 * nz) )
1876	ELSE
1877	th = tunnel_height
1878	ENDIF
1879	!
1880	!-- Tunnel-wall depth
1881	IF ( tunnel_wall_depth == 9999999.9_wp ) THEN
1882	td = MAX ( dx, dy, dz(1) )
1883	ELSE
1884	td = tunnel_wall_depth
1885	ENDIF
1886	!
1887	!-- Check for tunnel width
1888	IF ( tunnel_width_x == 9999999.9_wp .AND. &
1889	tunnel_width_y == 9999999.9_wp ) THEN
1890	message_string = 'No tunnel width is given. '
1891	CALL message( 'init_grid', 'PA0280', 1, 2, 0, 6, 0 )
1892	ENDIF
1893	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
1894	tunnel_width_y /= 9999999.9_wp ) THEN
1895	message_string = 'Inconsistent tunnel parameters:' // &
1896	'tunnel can only be oriented' // &
1897	'either in x- or in y-direction.'
1898	CALL message( 'init_grid', 'PA0281', 1, 2, 0, 6, 0 )
1899	ENDIF
1900	!
1901	!-- Check for too small tunnel width in x- and y-direction
1902	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
1903	tunnel_width_x - 2.0_wp * td <= 2.0_wp * dx ) THEN
1904	message_string = 'tunnel_width_x too small'
1905	CALL message( 'init_grid', 'PA0175', 1, 2, 0, 6, 0 )
1906	ENDIF
1907	IF ( tunnel_width_y /= 9999999.9_wp .AND. &
1908	tunnel_width_y - 2.0_wp * td <= 2.0_wp * dy ) THEN
1909	message_string = 'tunnel_width_y too small'
1910	CALL message( 'init_grid', 'PA0455', 1, 2, 0, 6, 0 )
1911	ENDIF
1912	!
1913	!-- Check for too large tunnel width.
1914	!-- Tunnel axis along y.
1915	IF ( tunnel_width_x /= 9999999.9_wp ) THEN
1916	IF ( tunnel_width_x > ( nx + 1 ) * dx ) THEN
1917	message_string = 'tunnel_width_x too large'
1918	CALL message( 'init_grid', 'PA0282', 1, 2, 0, 6, 0 )
1919	ENDIF
1920
1921	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_width_x * 0.5_wp )
1922	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_width_x * 0.5_wp )
1923	txs_in = INT( ( nx + 1 ) * 0.5_wp * dx - &
1924	( tunnel_width_x * 0.5_wp - td ) )
1925	txe_in = INT( ( nx + 1 ) * 0.5_wp * dx + &
1926	( tunnel_width_x * 0.5_wp - td ) )
1927
1928	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_length * 0.5_wp )
1929	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_length * 0.5_wp )
1930	tys_in = tys_out
1931	tye_in = tye_out
1932	ENDIF
1933	!
1934	!-- Tunnel axis along x.
1935	IF ( tunnel_width_y /= 9999999.9_wp ) THEN
1936	IF ( tunnel_width_y > ( ny + 1 ) * dy ) THEN
1937	message_string = 'tunnel_width_y too large'
1938	CALL message( 'init_grid', 'PA0456', 1, 2, 0, 6, 0 )
1939	ENDIF
1940
1941	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_length * 0.5_wp )
1942	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_length * 0.5_wp )
1943	txs_in = txs_out
1944	txe_in = txe_out
1945
1946	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_width_y * 0.5_wp )
1947	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_width_y * 0.5_wp )
1948	tys_in = INT( ( ny + 1 ) * 0.5_wp * dy - &
1949	( tunnel_width_y * 0.5_wp - td ) )
1950	tye_in = INT( ( ny + 1 ) * 0.5_wp * dy + &
1951	( tunnel_width_y * 0.5_wp - td ) )
1952	ENDIF
1953
1954	topo = 0
1955	DO i = nxl, nxr
1956	DO j = nys, nyn
1957	!
1958	!-- Use heaviside function to model outer tunnel surface
1959	hv_out = th * 0.5_wp * &
1960	( ( SIGN( 1.0_wp, i * dx - txs_out ) + 1.0_wp ) &
1961	- ( SIGN( 1.0_wp, i * dx - txe_out ) + 1.0_wp ) )
1962
1963	hv_out = hv_out * 0.5_wp * &
1964	( ( SIGN( 1.0_wp, j * dy - tys_out ) + 1.0_wp ) &
1965	- ( SIGN( 1.0_wp, j * dy - tye_out ) + 1.0_wp ) )
1966	!
1967	!-- Use heaviside function to model inner tunnel surface
1968	hv_in = ( th - td ) * 0.5_wp * &
1969	( ( SIGN( 1.0_wp, i * dx - txs_in ) + 1.0_wp ) &
1970	- ( SIGN( 1.0_wp, i * dx - txe_in ) + 1.0_wp ) )
1971
1972	hv_in = hv_in * 0.5_wp * &
1973	( ( SIGN( 1.0_wp, j * dy - tys_in ) + 1.0_wp ) &
1974	- ( SIGN( 1.0_wp, j * dy - tye_in ) + 1.0_wp ) )
1975	!
1976	!-- Set flags at x-y-positions without any tunnel surface
1977	IF ( hv_out - hv_in == 0.0_wp ) THEN
1978	topo(nzb+1:nzt+1,j,i) = IBSET( topo(nzb+1:nzt+1,j,i), 0 )
1979	!
1980	!-- Set flags at x-y-positions with tunnel surfaces
1981	ELSE
1982	DO k = nzb + 1, nzt + 1
1983	!
1984	!-- Inner tunnel
1985	IF ( hv_out - hv_in == th ) THEN
1986	IF ( zw(k) <= hv_out ) THEN
1987	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
1988	ELSE
1989	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
1990	ENDIF
1991	ENDIF
1992	!
1993	!-- Lateral tunnel walls
1994	IF ( hv_out - hv_in == td ) THEN
1995	IF ( zw(k) <= hv_in ) THEN
1996	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
1997	ELSEIF ( zw(k) > hv_in .AND. zw(k) <= hv_out ) THEN
1998	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
1999	ELSEIF ( zw(k) > hv_out ) THEN
2000	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2001	ENDIF
2002	ENDIF
2003	ENDDO
2004	ENDIF
2005	ENDDO
2006	ENDDO
2007
2008	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2009	!
2010	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2011	!-- boundary conditions for topography.
2012	IF ( .NOT. bc_ns_cyc ) THEN
2013	IF ( nys == 0 ) THEN
2014	DO i = 1, nbgp
2015	topo(:,nys-i,:) = topo(:,nys,:)
2016	ENDDO
2017	ENDIF
2018	IF ( nyn == ny ) THEN
2019	DO i = 1, nbgp
2020	topo(:,nyn+i,:) = topo(:,nyn,:)
2021	ENDDO
2022	ENDIF
2023	ENDIF
2024	IF ( .NOT. bc_lr_cyc ) THEN
2025	IF ( nxl == 0 ) THEN
2026	DO i = 1, nbgp
2027	topo(:,:,nxl-i) = topo(:,:,nxl)
2028	ENDDO
2029	ENDIF
2030	IF ( nxr == nx ) THEN
2031	DO i = 1, nbgp
2032	topo(:,:,nxr+i) = topo(:,:,nxr)
2033	ENDDO
2034	ENDIF
2035	ENDIF
2036
2037	CASE ( 'read_from_file' )
2038	!
2039	!-- Note, topography information have been already read.
2040	!-- If required, further process topography, i.e. reference buildings on
2041	!-- top of orography and set temporary 3D topography array, which is
2042	!-- used later to set grid flags. Calling of this rouinte is also
2043	!-- required in case of ASCII input, even though no distinction between
2044	!-- terrain- and building height is made in this case.
2045	CALL process_topography( topo )
2046	!
2047	!-- Filter holes resolved by only one grid-point
2048	CALL filter_topography( topo )
2049	!
2050	!-- Exchange ghost-points, as well as add cyclic or Neumann boundary
2051	!-- conditions.
2052	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2053	!
2054	!-- Set lateral boundary conditions for topography on all ghost layers
2055	IF ( .NOT. bc_ns_cyc ) THEN
2056	IF ( nys == 0 ) THEN
2057	DO i = 1, nbgp
2058	topo(:,nys-i,:) = topo(:,nys,:)
2059	ENDDO
2060	ENDIF
2061	IF ( nyn == ny ) THEN
2062	DO i = 1, nbgp
2063	topo(:,nyn+i,:) = topo(:,nyn,:)
2064	ENDDO
2065	ENDIF
2066	ENDIF
2067
2068	IF ( .NOT. bc_lr_cyc ) THEN
2069	IF ( nxl == 0 ) THEN
2070	DO i = 1, nbgp
2071	topo(:,:,nxl-i) = topo(:,:,nxl)
2072	ENDDO
2073	ENDIF
2074	IF ( nxr == nx ) THEN
2075	DO i = 1, nbgp
2076	topo(:,:,nxr+i) = topo(:,:,nxr)
2077	ENDDO
2078	ENDIF
2079	ENDIF
2080
2081
2082	CASE DEFAULT
2083	!
2084	!-- The DEFAULT case is reached either if the parameter topography
2085	!-- contains a wrong character string or if the user has defined a special
2086	!-- case in the user interface. There, the subroutine user_init_grid
2087	!-- checks which of these two conditions applies.
2088	CALL user_init_grid( topo )
2089	CALL filter_topography( topo )
2090
2091	END SELECT
2092	!
2093	!-- Consistency checks and index array initialization are only required for
2094	!-- non-flat topography.
2095	IF ( TRIM( topography ) /= 'flat' ) THEN
2096	!
2097	!-- In case of non-flat topography, check whether the convention how to
2098	!-- define the topography grid has been set correctly, or whether the default
2099	!-- is applicable. If this is not possible, abort.
2100	IF ( TRIM( topography_grid_convention ) == ' ' ) THEN
2101	IF ( TRIM( topography ) /= 'closed_channel' .AND. &
2102	TRIM( topography ) /= 'single_building' .AND. &
2103	TRIM( topography ) /= 'single_street_canyon' .AND. &
2104	TRIM( topography ) /= 'tunnel' .AND. &
2105	TRIM( topography ) /= 'read_from_file') THEN
2106	!-- The default value is not applicable here, because it is only valid
2107	!-- for the four standard cases 'single_building',
2108	!-- 'single_street_canyon', 'tunnel' and 'read_from_file'
2109	!-- defined in init_grid.
2110	WRITE( message_string, * ) &
2111	'The value for "topography_grid_convention" ', &
2112	'is not set. Its default value is & only valid for ', &
2113	'"topography" = ''single_building'', ''tunnel'' ', &
2114	'''single_street_canyon'', ''closed_channel'' & or ', &
2115	'''read_from_file''.', &
2116	'& Choose ''cell_edge'' or ''cell_center''.'
2117	CALL message( 'init_grid', 'PA0239', 1, 2, 0, 6, 0 )
2118	ELSE
2119	!-- The default value is applicable here.
2120	!-- Set convention according to topography.
2121	IF ( TRIM( topography ) == 'single_building' .OR. &
2122	TRIM( topography ) == 'single_street_canyon' ) THEN
2123	topography_grid_convention = 'cell_edge'
2124	ELSEIF ( TRIM( topography ) == 'read_from_file' .OR. &
2125	TRIM( topography ) == 'tunnel') THEN
2126	topography_grid_convention = 'cell_center'
2127	ENDIF
2128	ENDIF
2129	ELSEIF ( TRIM( topography_grid_convention ) /= 'cell_edge' .AND. &
2130	TRIM( topography_grid_convention ) /= 'cell_center' ) THEN
2131	WRITE( message_string, * ) &
2132	'The value for "topography_grid_convention" is ', &
2133	'not recognized.& Choose ''cell_edge'' or ''cell_center''.'
2134	CALL message( 'init_grid', 'PA0240', 1, 2, 0, 6, 0 )
2135	ENDIF
2136
2137
2138	IF ( topography_grid_convention == 'cell_edge' ) THEN
2139	!
2140	!-- The array nzb_local as defined using the 'cell_edge' convention
2141	!-- describes the actual total size of topography which is defined at the
2142	!-- cell edges where u=0 on the topography walls in x-direction and v=0
2143	!-- on the topography walls in y-direction. However, PALM uses individual
2144	!-- arrays nzb_u\|v\|w\|s_inner\|outer that are based on nzb_s_inner.
2145	!-- Therefore, the extent of topography in nzb_local is now reduced by
2146	!-- 1dx at the E topography walls and by 1dy at the N topography walls
2147	!-- to form the basis for nzb_s_inner.
2148	!-- Note, the reverse memory access (i-j instead of j-i) is absolutely
2149	!-- required at this point.
2150	DO j = nys+1, nyn+1
2151	DO i = nxl-1, nxr
2152	DO k = nzb, nzt+1
2153	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2154	BTEST( topo(k,j,i+1), 0 ) ) &
2155	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2156	ENDDO
2157	ENDDO
2158	ENDDO
2159	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2160
2161	DO i = nxl, nxr+1
2162	DO j = nys-1, nyn
2163	DO k = nzb, nzt+1
2164	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2165	BTEST( topo(k,j+1,i), 0 ) ) &
2166	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2167	ENDDO
2168	ENDDO
2169	ENDDO
2170	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2171
2172	ENDIF
2173	ENDIF
2174
2175
2176	END SUBROUTINE init_topo
2177
2178	SUBROUTINE set_topo_flags(topo)
2179
2180	USE control_parameters, &
2181	ONLY: bc_lr_cyc, bc_ns_cyc, constant_flux_layer, &
2182	scalar_advec, topography, use_surface_fluxes, use_top_fluxes
2183
2184	USE indices, &
2185	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
2186	nzt, topo_top_ind, wall_flags_static_0, wall_flags_total_0
2187
2188	USE kinds
2189
2190	IMPLICIT NONE
2191
2192	INTEGER(iwp) :: i !< index variable along x
2193	INTEGER(iwp) :: ibit !< integer bit position of topgraphy masking array
2194	INTEGER(iwp) :: j !< index variable along y
2195	INTEGER(iwp) :: k !< index variable along z
2196
2197	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
2198
2199	ALLOCATE( wall_flags_static_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2200	wall_flags_static_0 = 0
2201	!
2202	!-- Set-up topography flags. First, set flags only for s, u, v and w-grid.
2203	!-- Further special flags will be set in following loops.
2204	DO i = nxl, nxr
2205	DO j = nys, nyn
2206	DO k = nzb, nzt+1
2207	!
2208	!-- scalar grid
2209	IF ( BTEST( topo(k,j,i), 0 ) ) &
2210	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 0 )
2211	!
2212	!-- u grid
2213	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2214	BTEST( topo(k,j,i-1), 0 ) ) &
2215	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 1 )
2216	!
2217	!-- v grid
2218	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2219	BTEST( topo(k,j-1,i), 0 ) ) &
2220	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 2 )
2221
2222	ENDDO
2223
2224	DO k = nzb, nzt
2225	!
2226	!-- w grid
2227	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2228	BTEST( topo(k+1,j,i), 0 ) ) &
2229	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 3 )
2230	ENDDO
2231
2232	IF ( topography /= 'closed_channel' ) THEN
2233	wall_flags_static_0(nzt+1,j,i) = IBSET( wall_flags_static_0(nzt+1,j,i), 3 )
2234	ENDIF
2235
2236	ENDDO
2237	ENDDO
2238
2239	CALL exchange_horiz_int( wall_flags_static_0, nys, nyn, nxl, nxr, nzt, nbgp )
2240
2241	!
2242	!-- Set outer array for scalars to mask near-surface grid points. Note, on
2243	!-- basis of flag 24 futher flags will be derived which are used to control
2244	!-- production of subgrid TKE production near walls.
2245
2246	ALLOCATE( wall_flags_total_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2247	wall_flags_total_0 = 0
2248
2249	DO i = nxl, nxr
2250	DO j = nys, nyn
2251	DO k = nzb, nzt+1
2252	wall_flags_total_0(k,j,i) = IOR( wall_flags_total_0(k,j,i), wall_flags_static_0(k,j,i) )
2253	ENDDO
2254	ENDDO
2255	ENDDO
2256
2257	CALL exchange_horiz_int( wall_flags_total_0, nys, nyn, nxl, nxr, nzt, nbgp )
2258
2259	DO i = nxl, nxr
2260	DO j = nys, nyn
2261	DO k = nzb, nzt+1
2262	IF ( BTEST( wall_flags_total_0(k,j-1,i), 0 ) .AND. &
2263	BTEST( wall_flags_total_0(k,j+1,i), 0 ) .AND. &
2264	BTEST( wall_flags_total_0(k,j,i-1), 0 ) .AND. &
2265	BTEST( wall_flags_total_0(k,j,i+1), 0 ) .AND. &
2266	BTEST( wall_flags_total_0(k,j-1,i-1), 0 ) .AND. &
2267	BTEST( wall_flags_total_0(k,j+1,i-1), 0 ) .AND. &
2268	BTEST( wall_flags_total_0(k,j-1,i+1), 0 ) .AND. &
2269	BTEST( wall_flags_total_0(k,j+1,i+1), 0 ) ) &
2270	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 24 )
2271	ENDDO
2272	ENDDO
2273	ENDDO
2274	!
2275	!-- Set further special flags
2276	DO i = nxl, nxr
2277	DO j = nys, nyn
2278	DO k = nzb, nzt+1
2279	!
2280	!-- scalar grid, former nzb_diff_s_inner.
2281	!-- Note, use this flag also to mask topography in diffusion_u and
2282	!-- diffusion_v along the vertical direction. In case of
2283	!-- use_surface_fluxes, fluxes are calculated via MOST, else, simple
2284	!-- gradient approach is applied. Please note, in case of u- and v-
2285	!-- diffuison, a small error is made at edges (on the east side for u,
2286	!-- at the north side for v), since topography on scalar grid point
2287	!-- is used instead of topography on u/v-grid. As number of topography grid
2288	!-- points on uv-grid is different than s-grid, different number of
2289	!-- surface elements would be required. In order to avoid this,
2290	!-- treat edges (u(k,j,i+1)) simply by a gradient approach, i.e. these
2291	!-- points are not masked within diffusion_u. Tests had shown that the
2292	!-- effect on the flow is negligible.
2293	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2294	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2295	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 8 )
2296	ELSE
2297	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 8 )
2298	ENDIF
2299
2300	ENDDO
2301	!
2302	!-- Special flag to control vertical diffusion at model top - former
2303	!-- nzt_diff
2304	wall_flags_total_0(:,j,i) = IBSET( wall_flags_total_0(:,j,i), 9 )
2305	IF ( use_top_fluxes ) &
2306	wall_flags_total_0(nzt+1,j,i) = IBCLR( wall_flags_total_0(nzt+1,j,i), 9 )
2307
2308
2309	DO k = nzb+1, nzt
2310	!
2311	!-- Special flag on u grid, former nzb_u_inner + 1, required
2312	!-- for disturb_field and initialization. Do not disturb directly at
2313	!-- topography, as well as initialize u with zero one grid point outside
2314	!-- of topography.
2315	IF ( BTEST( wall_flags_total_0(k-1,j,i), 1 ) .AND. &
2316	BTEST( wall_flags_total_0(k,j,i), 1 ) .AND. &
2317	BTEST( wall_flags_total_0(k+1,j,i), 1 ) ) &
2318	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 20 )
2319	!
2320	!-- Special flag on v grid, former nzb_v_inner + 1, required
2321	!-- for disturb_field and initialization. Do not disturb directly at
2322	!-- topography, as well as initialize v with zero one grid point outside
2323	!-- of topography.
2324	IF ( BTEST( wall_flags_total_0(k-1,j,i), 2 ) .AND. &
2325	BTEST( wall_flags_total_0(k,j,i), 2 ) .AND. &
2326	BTEST( wall_flags_total_0(k+1,j,i), 2 ) ) &
2327	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 21 )
2328	!
2329	!-- Special flag on scalar grid, former nzb_s_inner+1. Used for
2330	!-- lpm_sgs_tke
2331	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2332	BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2333	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2334	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 25 )
2335	!
2336	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2337	!-- in production_e
2338	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2339	IF ( BTEST( wall_flags_total_0(k,j,i), 24 ) .AND. &
2340	BTEST( wall_flags_total_0(k-1,j,i), 24 ) .AND. &
2341	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2342	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 29 )
2343	ELSE
2344	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2345	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 29 )
2346	ENDIF
2347	!
2348	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2349	!-- in production_e
2350	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2351	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2352	BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2353	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2354	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 30 )
2355	ELSE
2356	IF ( 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), 30 )
2358	ENDIF
2359	ENDDO
2360	!
2361	!-- Flags indicating downward facing walls
2362	DO k = nzb+1, nzt+1
2363	!
2364	!-- Scalar grid
2365	IF ( BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2366	.NOT. BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2367	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 13 )
2368	!
2369	!-- Downward facing wall on u grid
2370	IF ( BTEST( wall_flags_total_0(k-1,j,i), 1 ) .AND. &
2371	.NOT. BTEST( wall_flags_total_0(k,j,i), 1 ) ) &
2372	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 15 )
2373	!
2374	!-- Downward facing wall on v grid
2375	IF ( BTEST( wall_flags_total_0(k-1,j,i), 2 ) .AND. &
2376	.NOT. BTEST( wall_flags_total_0(k,j,i), 2 ) ) &
2377	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 17 )
2378	!
2379	!-- Downward facing wall on w grid
2380	IF ( BTEST( wall_flags_total_0(k-1,j,i), 3 ) .AND. &
2381	.NOT. BTEST( wall_flags_total_0(k,j,i), 3 ) ) &
2382	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 19 )
2383	ENDDO
2384	!
2385	!-- Flags indicating upward facing walls
2386	DO k = nzb, nzt
2387	!
2388	!-- Upward facing wall on scalar grid
2389	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2390	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2391	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 12 )
2392	!
2393	!-- Upward facing wall on u grid
2394	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 1 ) .AND. &
2395	BTEST( wall_flags_total_0(k+1,j,i), 1 ) ) &
2396	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 14 )
2397
2398	!
2399	!-- Upward facing wall on v grid
2400	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 2 ) .AND. &
2401	BTEST( wall_flags_total_0(k+1,j,i), 2 ) ) &
2402	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 16 )
2403
2404	!
2405	!-- Upward facing wall on w grid
2406	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 3 ) .AND. &
2407	BTEST( wall_flags_total_0(k+1,j,i), 3 ) ) &
2408	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 18 )
2409	!
2410	!-- Special flag on scalar grid, former nzb_s_inner
2411	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .OR. &
2412	BTEST( wall_flags_total_0(k,j,i), 12 ) .OR. &
2413	BTEST( wall_flags_total_0(k,j,i), 13 ) ) &
2414	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 22 )
2415	!
2416	!-- Special flag on scalar grid, nzb_diff_s_inner - 1, required for
2417	!-- flow_statistics
2418	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2419	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2420	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2421	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 23 )
2422	ELSE
2423	IF ( BTEST( wall_flags_total_0(k,j,i), 22 ) ) &
2424	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 23 )
2425	ENDIF
2426
2427
2428	ENDDO
2429	wall_flags_total_0(nzt+1,j,i) = IBSET( wall_flags_total_0(nzt+1,j,i), 22 )
2430	wall_flags_total_0(nzt+1,j,i) = IBSET( wall_flags_total_0(nzt+1,j,i), 23 )
2431	!
2432	!-- Set flags indicating that topography is close by in horizontal
2433	!-- direction, i.e. flags that infold the topography. These will be used
2434	!-- to set advection flags for passive scalars, where due to large
2435	!-- gradients near buildings stationary numerical oscillations can produce
2436	!-- unrealistically high concentrations. This is only necessary if
2437	!-- WS-scheme is applied for scalar advection. Note, these flags will be
2438	!-- only used for passive scalars such as chemical species or aerosols.
2439	IF ( scalar_advec == 'ws-scheme' ) THEN
2440	DO k = nzb, nzt
2441	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. ( &
2442	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-1), 0 ) ) .OR.&
2443	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-2), 0 ) ) .OR.&
2444	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-3), 0 ) ) .OR.&
2445	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+1), 0 ) ) .OR.&
2446	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+2), 0 ) ) .OR.&
2447	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+3), 0 ) ) .OR.&
2448	ANY( .NOT. BTEST( wall_flags_total_0(k,j-1,i-3:i+3), 0 ) ) .OR.&
2449	ANY( .NOT. BTEST( wall_flags_total_0(k,j-2,i-3:i+3), 0 ) ) .OR.&
2450	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3,i-3:i+3), 0 ) ) .OR.&
2451	ANY( .NOT. BTEST( wall_flags_total_0(k,j+1,i-3:i+3), 0 ) ) .OR.&
2452	ANY( .NOT. BTEST( wall_flags_total_0(k,j+2,i-3:i+3), 0 ) ) .OR.&
2453	ANY( .NOT. BTEST( wall_flags_total_0(k,j+3,i-3:i+3), 0 ) ) &
2454	) ) &
2455	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 31 )
2456
2457	ENDDO
2458	ENDIF
2459	ENDDO
2460	ENDDO
2461	!
2462	!-- Finally, set identification flags indicating natural terrain or buildings.
2463	!-- Natural terrain grid points. Information on the type of the surface is
2464	!-- stored in bit 1 of 3D Integer array topo. However, this bit is only set
2465	!-- when topography is read from file. In order to run the land-surface model
2466	!-- also without topography information, set bit 1 explicitely in this case.
2467	!--
2468	!-- Natural terrain grid points
2469	!-- If no topography is initialized, the land-surface is at k = nzb.
2470	IF ( TRIM( topography ) /= 'read_from_file' ) THEN
2471	wall_flags_static_0(nzb,:,:) = IBSET( wall_flags_static_0(nzb,:,:), 5 )
2472	ELSE
2473	DO i = nxl, nxr
2474	DO j = nys, nyn
2475	DO k = nzb, nzt+1
2476	!
2477	!-- Natural terrain grid point
2478	IF ( BTEST( topo(k,j,i), 1 ) ) &
2479	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 5 )
2480	ENDDO
2481	ENDDO
2482	ENDDO
2483	ENDIF
2484	!
2485	!-- Building grid points.
2486	DO i = nxl, nxr
2487	DO j = nys, nyn
2488	DO k = nzb, nzt+1
2489	IF ( BTEST( topo(k,j,i), 2 ) ) &
2490	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 6 )
2491	ENDDO
2492	ENDDO
2493	ENDDO
2494	!
2495	!-- Set flag 4, indicating new topography grid points due to filtering.
2496	DO i = nxl, nxr
2497	DO j = nys, nyn
2498	DO k = nzb, nzt+1
2499	IF ( BTEST( topo(k,j,i), 4 ) ) &
2500	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 4 )
2501	ENDDO
2502	ENDDO
2503	ENDDO
2504
2505	CALL exchange_horiz_int( wall_flags_static_0, nys, nyn, nxl, nxr, nzt, nbgp )
2506
2507	DO i = nxl, nxr
2508	DO j = nys, nyn
2509	DO k = nzb, nzt+1
2510	wall_flags_total_0(k,j,i) = IOR( wall_flags_total_0(k,j,i), wall_flags_static_0(k,j,i) )
2511	ENDDO
2512	ENDDO
2513	ENDDO
2514	!
2515	!-- Exchange ghost points for wall flags
2516	CALL exchange_horiz_int( wall_flags_total_0, nys, nyn, nxl, nxr, nzt, nbgp )
2517	!
2518	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2519	!-- boundary conditions for topography.
2520	IF ( .NOT. bc_ns_cyc ) THEN
2521	IF ( nys == 0 ) THEN
2522	DO i = 1, nbgp
2523	wall_flags_total_0(:,nys-i,:) = wall_flags_total_0(:,nys,:)
2524	ENDDO
2525	ENDIF
2526	IF ( nyn == ny ) THEN
2527	DO i = 1, nbgp
2528	wall_flags_total_0(:,nyn+i,:) = wall_flags_total_0(:,nyn,:)
2529	ENDDO
2530	ENDIF
2531	ENDIF
2532	IF ( .NOT. bc_lr_cyc ) THEN
2533	IF ( nxl == 0 ) THEN
2534	DO i = 1, nbgp
2535	wall_flags_total_0(:,:,nxl-i) = wall_flags_total_0(:,:,nxl)
2536	ENDDO
2537	ENDIF
2538	IF ( nxr == nx ) THEN
2539	DO i = 1, nbgp
2540	wall_flags_total_0(:,:,nxr+i) = wall_flags_total_0(:,:,nxr)
2541	ENDDO
2542	ENDIF
2543	ENDIF
2544	!
2545	!-- Pre-calculate topography top indices (former get_topography_top_index
2546	!-- function)
2547	ALLOCATE( topo_top_ind(nysg:nyng,nxlg:nxrg,0:4) )
2548	!
2549	!-- Uppermost topography index on scalar grid
2550	ibit = 12
2551	topo_top_ind(:,:,0) = MAXLOC( &
2552	MERGE( 1, 0, &
2553	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2554	), DIM = 1 &
2555	) - 1
2556	!
2557	!-- Uppermost topography index on u grid
2558	ibit = 14
2559	topo_top_ind(:,:,1) = MAXLOC( &
2560	MERGE( 1, 0, &
2561	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2562	), DIM = 1 &
2563	) - 1
2564	!
2565	!-- Uppermost topography index on v grid
2566	ibit = 16
2567	topo_top_ind(:,:,2) = MAXLOC( &
2568	MERGE( 1, 0, &
2569	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2570	), DIM = 1 &
2571	) - 1
2572	!
2573	!-- Uppermost topography index on w grid
2574	ibit = 18
2575	topo_top_ind(:,:,3) = MAXLOC( &
2576	MERGE( 1, 0, &
2577	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2578	), DIM = 1 &
2579	) - 1
2580	!
2581	!-- Uppermost topography index on scalar outer grid
2582	ibit = 24
2583	topo_top_ind(:,:,4) = MAXLOC( &
2584	MERGE( 1, 0, &
2585	BTEST( wall_flags_total_0(:,:,:), ibit ) &
2586	), DIM = 1 &
2587	) - 1
2588
2589	END SUBROUTINE set_topo_flags
2590
2591
2592
2593

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