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source: palm/trunk/SOURCE/init_grid.f90 @ 4648

Last change on this file since 4648 was 4648, checked in by raasch, 4 years ago
files re-formatted to follow the PALM coding standard
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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 terms of the GNU General
6	! Public License as published by the Free Software Foundation, either version 3 of the License, or
7	! (at your option) any later version.
8	!
9	! PALM is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
10	! implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
11	! Public License for more details.
12	!
13	! You should have received a copy of the GNU General Public License along with PALM. If not, see
14	! <http://www.gnu.org/licenses/>.
15	!
16	! Copyright 1997-2020 Leibniz Universitaet Hannover
17	!--------------------------------------------------------------------------------------------------!
18	!
19	! Current revisions:
20	! -----------------
21	!
22	!
23	! Former revisions:
24	! -----------------
25	! $Id: init_grid.f90 4648 2020-08-25 07:52:08Z raasch $
26	! file re-formatted to follow the PALM coding standard
27	!
28	! 4630 2020-07-30 14:54:34Z suehring
29	! In case of ASCII topography input flag grid points as terrain and building.
30	!
31	! 4601 2020-07-14 12:06:09Z suehring
32	! Minor formatting adjustments
33	!
34	! 4564 2020-06-12 14:03:36Z raasch
35	! Vertical nesting method of Huq et al. (2019) removed
36	!
37	! 4543 2020-05-20 14:12:22Z gronemeier
38	! Remove non-required check for canyon height
39	!
40	! 4507 2020-04-22 18:21:45Z gronemeier
41	! update origin_z with shifting height of orography (oro_min)
42	!
43	! 4457 2020-03-11 14:20:43Z raasch
44	! use statement for exchange horiz added,
45	! bugfix for call of exchange horiz 2d
46	!
47	! 4444 2020-03-05 15:59:50Z raasch
48	! bugfix: cpp-directives for serial mode added
49	!
50	! 4414 2020-02-19 20:16:04Z suehring
51	! - Remove deprecated topography arrays nzb_s_inner, nzb_u_inner, etc.
52	! - Move initialization of boundary conditions and multigrid into an extra module interface.
53	!
54	! 4386 2020-01-27 15:07:30Z Giersch
55	! Allocation statements, comments, naming of variables revised and _wp added to real type values
56	!
57	! 4360 2020-01-07 11:25:50Z suehring
58	! Revise error messages for generic tunnel setup.
59	!
60	! 4346 2019-12-18 11:55:56Z motisi
61	! Introduction of wall_flags_total_0, which currently sets bits based on static topography
62	! information used in wall_flags_static_0
63	!
64	! 4340 2019-12-16 08:17:03Z Giersch
65	! Topography closed channel flow with symmetric boundaries implemented
66	!
67	! 4329 2019-12-10 15:46:36Z motisi
68	! Renamed wall_flags_0 to wall_flags_static_0
69	!
70	! 4328 2019-12-09 18:53:04Z suehring
71	! Minor change in nzb_max computation. Commentation added.
72	!
73	! 4314 2019-11-29 10:29:20Z suehring
74	! Set additional topography flag 4 to mark topography grid points emerged from the filtering process.
75	!
76	! 4294 2019-11-13 18:34:16Z suehring
77	! Bugfix, always set bit 5 and 6 of wall_flags, indicating terrain- and building surfaces in all
78	! cases, in order to enable terrain-following output also when no land- or urban-surface model is
79	! applied.
80	!
81	! 4265 2019-10-15 16:16:24Z suehring
82	! Bugfix for last commit, exchange oro_max variable only when it is allocated (not necessarily the
83	! case when topography is input from ASCII file).
84	!
85	! 4245 2019-09-30 08:40:37Z pavelkrc
86	! Store oro_max (building z-offset) in 2D for building surfaces
87	!
88	! 4189 2019-08-26 16:19:38Z suehring
89	! - Add check for proper setting of namelist parameter topography
90	! - Set flag to indicate land surfaces in case no topography is provided
91	!
92	! 4182 2019-08-22 15:20:23Z scharf
93	! Corrected "Former revisions" section
94	!
95	! 4168 2019-08-16 13:50:17Z suehring
96	! Pre-calculate topography top index and store it on an array (replaces former functions
97	! get_topography_top_index)
98	!
99	! 4159 2019-08-15 13:31:35Z suehring
100	! Revision of topography processing. This was not consistent between 2D and 3D buildings.
101	!
102	! 4144 2019-08-06 09:11:47Z raasch
103	! relational operators .EQ., .NE., etc. replaced by ==, /=, etc.
104	!
105	! 4115 2019-07-24 12:50:49Z suehring
106	! Bugfix in setting near-surface flag 24, inidicating wall-bounded grid points
107	!
108	! 4110 2019-07-22 17:05:21Z suehring
109	! - Separate initialization of advection flags for momentum and scalars.
110	! - Change subroutine interface for ws_init_flags_scalar to pass boundary flags
111	!
112	! 4109 2019-07-22 17:00:34Z suehring
113	! Fix bad commit
114	!
115	! 3926 2019-04-23 12:56:42Z suehring
116	! Minor bugfix in building mapping when all building IDs in the model domain are missing
117	!
118	! 3857 2019-04-03 13:00:16Z knoop
119	! In projection of non-building 3D objects onto numerical grid remove dependency on building_type
120	!
121	! 3763 2019-02-25 17:33:49Z suehring
122	! Replace work-around for ghost point exchange of 1-byte arrays with specific routine as already
123	! done in other routines
124	!
125	! 3761 2019-02-25 15:31:42Z raasch
126	! unused variables removed
127	!
128	! 3661 2019-01-08 18:22:50Z suehring
129	! Remove setting of nzb_max to nzt at non-cyclic boundary PEs, instead, order degradation of
130	! advection scheme is handeled directly in advec_ws
131	!
132	! 3655 2019-01-07 16:51:22Z knoop
133	! Comment added
134	!
135	! Revision 1.1 1997/08/11 06:17:45 raasch
136	! Initial revision (Testversion)
137	!
138	!
139	! Description:
140	! -------------------------------------------------------------------------------------------------!
141	!> Creating grid depending constants
142	!> @todo: Rearrange topo flag list
143	!> @todo: reference 3D buildings on top of orography is not tested and may need further improvement
144	!> for steep slopes
145	!> @todo: Use more advanced setting of building type at filled holes
146	!--------------------------------------------------------------------------------------------------!
147	SUBROUTINE init_grid
148
149	USE arrays_3d, &
150	ONLY: dd2zu, ddzu, ddzu_pres, ddzw, dzu, dzw, x, xu, y, yv, zu, zw
151
152	USE control_parameters, &
153	ONLY: constant_flux_layer, dz, dz_max, dz_stretch_factor, &
154	dz_stretch_factor_array, dz_stretch_level, dz_stretch_level_end, &
155	dz_stretch_level_end_index, dz_stretch_level_start_index, &
156	dz_stretch_level_start, ibc_uv_b, message_string, &
157	number_stretch_level_end, &
158	number_stretch_level_start, &
159	ocean_mode, &
160	psolver, &
161	symmetry_flag, &
162	topography, &
163	use_surface_fluxes
164
165	USE grid_variables, &
166	ONLY: ddx, ddx2, ddy, ddy2, dx, dx2, dy, dy2, zu_s_inner, zw_w_inner
167
168	USE indices, &
169	ONLY: nbgp, &
170	nx, &
171	nxl, &
172	nxlg, &
173	nxr, &
174	nxrg, &
175	ny, &
176	nyn, &
177	nyng, &
178	nys, &
179	nysg, &
180	nz, &
181	nzb, &
182	nzb_diff, &
183	nzb_max, &
184	nzt, &
185	topo_top_ind, &
186	topo_min_level
187
188	USE kinds
189
190	USE pegrid
191
192	IMPLICIT NONE
193
194	INTEGER(iwp) :: i !< index variable along x
195	INTEGER(iwp) :: j !< index variable along y
196	INTEGER(iwp) :: k !< index variable along z
197	INTEGER(iwp) :: k_top !< topography top index on local PE
198	INTEGER(iwp) :: n !< loop variable for stretching
199	INTEGER(iwp) :: number_dz !< number of user-specified dz values
200	INTEGER(iwp) :: nzb_local_max !< vertical grid index of maximum topography height
201	INTEGER(iwp) :: nzb_local_min !< vertical grid index of minimum topography height
202
203	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
204
205	REAL(wp) :: dz_level_end !< distance between calculated height level for u/v-grid and user-specified end level for stretching
206	REAL(wp) :: dz_stretched !< stretched vertical grid spacing
207
208	REAL(wp), DIMENSION(:), ALLOCATABLE :: min_dz_stretch_level_end !< Array that contains all minimum heights where the stretching
209	!< can end
210
211
212	!
213	!-- Calculation of horizontal array bounds including ghost layers
214	nxlg = nxl - nbgp
215	nxrg = nxr + nbgp
216	nysg = nys - nbgp
217	nyng = nyn + nbgp
218
219	!
220	!-- Allocate grid arrays
221	ALLOCATE( x(0:nx) )
222	ALLOCATE( xu(0:nx) )
223
224	DO i = 0, nx
225	xu(i) = i * dx
226	x(i) = i * dx + 0.5_wp * dx
227	ENDDO
228
229	ALLOCATE( y(0:ny) )
230	ALLOCATE( yv(0:ny) )
231
232	DO j = 0, ny
233	yv(j) = j * dy
234	y(j) = j * dy + 0.5_wp * dy
235	ENDDO
236
237	ALLOCATE( ddzu(1:nzt+1) )
238	ALLOCATE( ddzw(1:nzt+1) )
239	ALLOCATE( dd2zu(1:nzt) )
240	ALLOCATE( dzu(1:nzt+1) )
241	ALLOCATE( dzw(1:nzt+1) )
242	ALLOCATE( zu(nzb:nzt+1) )
243	ALLOCATE( zw(nzb:nzt+1) )
244
245	!
246	!-- For constructing an appropriate grid, the vertical grid spacing dz has to be specified with a
247	!-- non-negative value in the parameter file.
248	IF ( dz(1) == -1.0_wp ) THEN
249	message_string = 'missing dz'
250	CALL message( 'init_grid', 'PA0200', 1, 2, 0, 6, 0 )
251	ELSEIF ( dz(1) <= 0.0_wp ) THEN
252	WRITE( message_string, * ) 'dz=',dz(1),' <= 0.0'
253	CALL message( 'init_grid', 'PA0201', 1, 2, 0, 6, 0 )
254	ENDIF
255
256	!
257	!-- Initialize dz_stretch_level_start with the value of dz_stretch_level if it was set by the user.
258	IF ( dz_stretch_level /= -9999999.9_wp ) THEN
259	dz_stretch_level_start(1) = dz_stretch_level
260	ENDIF
261
262	!
263	!-- Determine number of dz values and stretching levels specified by the user to allow right
264	!-- controlling of the stretching mechanism and to perform error checks. The additional requirement
265	!-- that dz /= dz_max for counting number of user-specified dz values is necessary. Otherwise
266	!-- restarts would abort if the old stretching mechanism with dz_stretch_level is used (Attention:
267	!-- The user is not allowed to specify a dz value equal to the default of dz_max = 999.0).
268	number_dz = COUNT( dz /= -1.0_wp .AND. dz /= dz_max)
269	number_stretch_level_start = COUNT( dz_stretch_level_start /= -9999999.9_wp )
270	number_stretch_level_end = COUNT( dz_stretch_level_end /= 9999999.9_wp )
271
272	!
273	!-- The number of specified end levels +1 has to be the same as the number
274	!-- of specified dz values
275	IF ( number_dz /= number_stretch_level_end + 1 ) THEN
276	WRITE( message_string, * ) 'The number of values for dz = ', number_dz, &
277	'has to be the same as& ', 'the number of values for ', &
278	'dz_stretch_level_end + 1 = ', number_stretch_level_end+1
279	CALL message( 'init_grid', 'PA0156', 1, 2, 0, 6, 0 )
280	ENDIF
281
282	!
283	!-- The number of specified start levels has to be the same or one less than the number of specified
284	!-- dz values
285	IF ( number_dz /= number_stretch_level_start + 1 .AND. &
286	number_dz /= number_stretch_level_start ) THEN
287	WRITE( message_string, * ) 'The number of values for dz = ', number_dz, &
288	'has to be the same as or one ', &
289	'more than& the number of values for ', &
290	'dz_stretch_level_start = ', number_stretch_level_start
291	CALL message( 'init_grid', 'PA0211', 1, 2, 0, 6, 0 )
292	ENDIF
293
294	!-- The number of specified start levels has to be the same or one more than the number of specified
295	!-- end levels
296	IF ( number_stretch_level_start /= number_stretch_level_end + 1 .AND. &
297	number_stretch_level_start /= number_stretch_level_end ) THEN
298	WRITE( message_string, * ) 'The number of values for ', &
299	'dz_stretch_level_start = ', dz_stretch_level_start, &
300	'has to be the ', 'same or one more than& the number of ', &
301	'values for dz_stretch_level_end = ', number_stretch_level_end
302	CALL message( 'init_grid', 'PA0216', 1, 2, 0, 6, 0 )
303	ENDIF
304
305	!
306	!-- Initialize dz for the free atmosphere with the value of dz_max
307	IF ( dz(number_stretch_level_start+1) == -1.0_wp .AND. 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 atmosphere is desired
313	!-- (dz_stretch_level_end was not specified for the free atmosphere)
314	IF ( number_stretch_level_start == number_stretch_level_end + 1 ) THEN
315	dz_stretch_factor_array(number_stretch_level_start) = dz_stretch_factor
316	ENDIF
317
318	!
319	!-- Allocation of arrays for stretching
320	ALLOCATE( min_dz_stretch_level_end(number_stretch_level_start) )
321
322	!
323	!-- Define the vertical grid levels. Start with atmosphere branch
324	IF ( .NOT. ocean_mode ) THEN
325
326	!
327	!-- The stretching region has to be large enough to allow for a smooth transition between two
328	!-- different grid spacings. The number 4 is an empirical value.
329	DO n = 1, number_stretch_level_start
330	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) + 4 * MAX( dz(n),dz(n+1) )
331	ENDDO
332
333	IF ( ANY( min_dz_stretch_level_end(1:number_stretch_level_start) > &
334	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
335	message_string= 'Each dz_stretch_level_end has to be larger ' // &
336	'than its corresponding value for &' // &
337	'dz_stretch_level_start + 4*MAX(dz(n),dz(n+1)) '// &
338	'to allow for smooth grid stretching'
339	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
340	ENDIF
341
342	!
343	!-- Stretching must not be applied within the surface layer (first two grid points). For the
344	!-- default case dz_stretch_level_start is negative. Therefore the absolut value is checked here.
345	IF ( ANY( ABS( dz_stretch_level_start ) <= dz(1) * 1.5_wp ) ) THEN
346	WRITE( message_string, * ) 'Each dz_stretch_level_start has to be ', &
347	'larger than ', dz(1) * 1.5
348	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
349	ENDIF
350
351	!
352	!-- The stretching has to start and end on a grid level. Therefore user-specified values are
353	!-- mapped to the next lowest level. The calculation of the first level is realized differently
354	!-- just because of historical reasons (the advanced/new stretching mechanism was realized in a
355	!-- way that results don't change if the old parameters dz_stretch_level, dz_stretch_factor and
356	!-- dz_max are used).
357	IF ( number_stretch_level_start /= 0 ) THEN
358	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) - dz(1)/2.0) / dz(1) ) &
359	* dz(1) + dz(1)/2.0
360	ENDIF
361
362	IF ( number_stretch_level_start > 1 ) THEN
363	DO n = 2, number_stretch_level_start
364	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / dz(n) ) * dz(n)
365	ENDDO
366	ENDIF
367
368	IF ( number_stretch_level_end /= 0 ) THEN
369	DO n = 1, number_stretch_level_end
370	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / dz(n+1) ) * dz(n+1)
371	ENDDO
372	ENDIF
373
374	!
375	!-- Determine stretching factor if necessary
376	IF ( number_stretch_level_end >= 1 ) THEN
377	CALL calculate_stretching_factor( number_stretch_level_end )
378	ENDIF
379
380	!
381	!-- Grid for atmosphere with surface at z=0 (k=0, w-grid).
382	!-- First compute the u- and v-levels. In case of dirichlet bc for u and v the first u/v- and
383	!-- w-level (k=0) are defined at same height (z=0).
384	!-- The second u-level (k=1) corresponds to the top of the surface layer. In case of symmetric
385	!-- boundaries (closed channel flow), the first grid point is always at z=0.
386	IF ( ibc_uv_b == 0 .OR. ibc_uv_b == 2 .OR. topography == 'closed_channel' ) THEN
387	zu(0) = 0.0_wp
388	ELSE
389	zu(0) = - dz(1) * 0.5_wp
390	ENDIF
391
392	zu(1) = dz(1) * 0.5_wp
393
394	!
395	!-- Determine u and v height levels considering the possibility of grid stretching in several
396	!-- heights.
397	n = 1
398	dz_stretch_level_start_index = nzt+1
399	dz_stretch_level_end_index = nzt+1
400	dz_stretched = dz(1)
401
402	!-- The default value of dz_stretch_level_start is negative, thus the first condition is true
403	!-- even if no stretching shall be applied. Hence, the second condition is also necessary.
404	DO k = 2, nzt+1-symmetry_flag
405	IF ( dz_stretch_level_start(n) <= zu(k-1) .AND. &
406	dz_stretch_level_start(n) /= -9999999.9_wp ) THEN
407	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
408
409	IF ( dz(n) > dz(n+1) ) THEN
410	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
411	ELSE
412	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
413	ENDIF
414
415	IF ( dz_stretch_level_start_index(n) == nzt+1 ) dz_stretch_level_start_index(n) = k-1
416
417	ENDIF
418
419	zu(k) = zu(k-1) + dz_stretched
420
421	!
422	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
423	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
424
425	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
426	zu(k) = dz_stretch_level_end(n)
427	dz_stretched = dz(n+1)
428	dz_stretch_level_end_index(n) = k
429	n = n + 1
430	ENDIF
431	ENDDO
432
433	!
434	!-- If a closed channel flow is simulated, make sure that grid structure is the same for both
435	!-- bottom and top boundary. (Hint: Using a different dz at the bottom and at the top makes no
436	!-- sense due to symmetric boundaries where dz should be equal. Therefore, different dz at the
437	!-- bottom and top causes an abort (see check_parameters).)
438	IF ( topography == 'closed_channel' ) THEN
439	zu(nzt+1) = zu(nzt) + dz(1) * 0.5_wp
440	ENDIF
441
442	!
443	!-- Compute the w-levels. They are always staggered half-way between the corresponding u-levels.
444	!-- In case of dirichlet bc for u and v at the ground the first u- and w-level (k=0) are defined
445	!-- at same height (z=0).
446	!-- Per default, the top w-level is extrapolated linearly. In case of a closed channel flow,
447	!-- zu(nzt+1) and zw(nzt) must be set explicitely.
448	!-- (Hint: Using a different dz at the bottom and at the top makes no sense due to symmetric
449	!-- boundaries where dz should be equal. Therefore, different dz at the bottom and top causes an
450	!-- abort (see check_parameters).)
451	zw(0) = 0.0_wp
452	DO k = 1, nzt-symmetry_flag
453	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
454	ENDDO
455	IF ( topography == 'closed_channel' ) THEN
456	zw(nzt) = zw(nzt-1) + dz(1)
457	zw(nzt+1) = zw(nzt) + dz(1)
458	ELSE
459	zw(nzt+1) = zw(nzt) + 2.0_wp * ( zu(nzt+1) - zw(nzt) )
460	ENDIF
461
462	ELSE !ocean branch
463
464	!
465	!-- The stretching region has to be large enough to allow for a smooth transition between two
466	!-- different grid spacings. The number 4 is an empirical value
467	DO n = 1, number_stretch_level_start
468	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) - 4 * MAX( dz(n),dz(n+1) )
469	ENDDO
470
471	IF ( ANY( min_dz_stretch_level_end (1:number_stretch_level_start) < &
472	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
473	message_string= 'Each dz_stretch_level_end has to be less ' // &
474	'than its corresponding value for &' // &
475	'dz_stretch_level_start - 4*MAX(dz(n),dz(n+1)) '// &
476	'to allow for smooth grid stretching'
477	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
478	ENDIF
479
480	!
481	!-- Stretching must not be applied close to the surface (last two grid points). For the default
482	!-- case dz_stretch_level_start is negative.
483	IF ( ANY( dz_stretch_level_start >= - dz(1) * 1.5_wp ) ) THEN
484	WRITE( message_string, * ) 'Each dz_stretch_level_start has to be ', &
485	'less than ', -dz(1) * 1.5
486	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
487	ENDIF
488
489	!
490	!-- The stretching has to start and end on a grid level. Therefore user-specified values are
491	!-- mapped to the next highest level. The calculation of the first level is realized differently
492	!-- just because of historical reasons (the advanced/new stretching mechanism was realized in a
493	!-- way that results don't change if the old parameters dz_stretch_level, dz_stretch_factor and
494	!-- dz_max are used)
495	IF ( number_stretch_level_start /= 0 ) THEN
496	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) + dz(1)/2.0) / dz(1) ) &
497	* dz(1) - dz(1)/2.0
498	ENDIF
499
500	IF ( number_stretch_level_start > 1 ) THEN
501	DO n = 2, number_stretch_level_start
502	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / dz(n) ) * dz(n)
503	ENDDO
504	ENDIF
505
506	IF ( number_stretch_level_end /= 0 ) THEN
507	DO n = 1, number_stretch_level_end
508	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / dz(n+1) ) * dz(n+1)
509	ENDDO
510	ENDIF
511
512	!
513	!-- Determine stretching factor if necessary
514	IF ( number_stretch_level_end >= 1 ) THEN
515	CALL calculate_stretching_factor( number_stretch_level_end )
516	ENDIF
517
518	!
519	!-- Grid for ocean with free water surface is at k=nzt (w-grid).
520	!-- In case of neumann bc at the ground the first first u-level (k=0) lies below the first
521	!-- w-level (k=0). In case of dirichlet bc the first u- and w-level are defined at same height,
522	!-- but staggered from the second level.
523	!-- The second u-level (k=1) corresponds to the top of the surface layer.
524	!-- z values are negative starting from z=0 (surface)
525	zu(nzt+1) = dz(1) * 0.5_wp
526	zu(nzt) = - dz(1) * 0.5_wp
527
528	!
529	!-- Determine u and v height levels considering the possibility of grid stretching in several
530	!-- heights.
531	n = 1
532	dz_stretch_level_start_index = 0
533	dz_stretch_level_end_index = 0
534	dz_stretched = dz(1)
535
536	DO k = nzt-1, 0, -1
537
538	IF ( dz_stretch_level_start(n) >= zu(k+1) ) THEN
539	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
540
541	IF ( dz(n) > dz(n+1) ) THEN
542	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
543	ELSE
544	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
545	ENDIF
546
547	IF ( dz_stretch_level_start_index(n) == 0 ) dz_stretch_level_start_index(n) = k+1
548
549	ENDIF
550
551	zu(k) = zu(k+1) - dz_stretched
552
553	!
554	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
555	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
556
557	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
558	zu(k) = dz_stretch_level_end(n)
559	dz_stretched = dz(n+1)
560	dz_stretch_level_end_index(n) = k
561	n = n + 1
562	ENDIF
563	ENDDO
564
565	!
566	!-- Compute the w-levels. They are always staggered half-way between the corresponding u-levels,
567	!-- except in case of dirichlet bc for u and v at the ground. In this case the first u- and
568	!-- w-level are defined at same height. The top w-level (nzt+1) is not used but set for
569	!-- consistency, since w and all scalar variables are defined up tp nzt+1.
570	zw(nzt+1) = dz(1)
571	zw(nzt) = 0.0_wp
572	DO k = 0, nzt
573	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
574	ENDDO
575
576	!
577	!-- In case of dirichlet bc for u and v the first u- and w-level are defined at same height.
578	IF ( ibc_uv_b == 0 ) THEN
579	zu(0) = zw(0)
580	ENDIF
581
582	ENDIF !End of defining the vertical grid levels
583
584	!
585	!-- Compute grid lengths.
586	DO k = 1, nzt+1
587	dzu(k) = zu(k) - zu(k-1)
588	ddzu(k) = 1.0_wp / dzu(k)
589	dzw(k) = zw(k) - zw(k-1)
590	ddzw(k) = 1.0_wp / dzw(k)
591	ENDDO
592
593	DO k = 1, nzt
594	dd2zu(k) = 1.0_wp / ( dzu(k) + dzu(k+1) )
595	ENDDO
596
597	!
598	!-- The FFT- SOR-pressure solvers assume grid spacings of a staggered grid everywhere. For the
599	!-- actual grid, the grid spacing at the lowest level is only dz/2, but should be dz. Therefore, an
600	!-- additional array containing with appropriate grid information is created for these solvers.
601	IF ( psolver(1:9) /= 'multigrid' ) THEN
602	ALLOCATE( ddzu_pres(1:nzt+1) )
603	ddzu_pres = ddzu
604	ddzu_pres(1) = ddzu_pres(2) ! change for lowest level
605	ENDIF
606
607	!
608	!-- Compute the reciprocal values of the horizontal grid lengths.
609	ddx = 1.0_wp / dx
610	ddy = 1.0_wp / dy
611	dx2 = dx * dx
612	dy2 = dy * dy
613	ddx2 = 1.0_wp / dx2
614	ddy2 = 1.0_wp / dy2
615
616	!
617	!-- Allocate 3D array to set topography
618	ALLOCATE( topo(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
619	topo = 0
620	!
621	!-- Initialize topography by generic topography or read topography from file.
622	CALL init_topo( topo )
623	!
624	!-- Set flags to mask topography on the grid.
625	CALL set_topo_flags( topo )
626
627	!
628	!-- Determine the maximum level of topography. It is used for steering the degradation of order of
629	!-- the applied advection scheme, as well in the lpm.
630	k_top = 0
631	DO i = nxl, nxr
632	DO j = nys, nyn
633	DO k = nzb, nzt + 1
634	k_top = MAX( k_top, MERGE( k, 0, .NOT. BTEST( topo(k,j,i), 0 ) ) )
635	ENDDO
636	ENDDO
637	ENDDO
638	#if defined( __parallel )
639	CALL MPI_ALLREDUCE( k_top, nzb_max, 1, MPI_INTEGER, MPI_MAX, comm2d, ierr )
640	#else
641	nzb_max = k_top
642	#endif
643	!
644	!-- Increment nzb_max by 1 in order to allow for proper diverengence correction.
645	!-- Further, in case topography extents up to the model top, limit to nzt.
646	nzb_max = MIN( nzb_max+1, nzt )
647	!
648	!-- Determine minimum index of topography. Usually, this will be nzb. In case there is elevated
649	!-- topography, however, the lowest topography will be higher.
650	!-- This index is e.g. used to calculate mean first-grid point atmosphere temperature, surface
651	!-- pressure and density, etc. .
652	topo_min_level = 0
653	#if defined( __parallel )
654	CALL MPI_ALLREDUCE( MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), topo_min_level, 1, MPI_INTEGER, &
655	MPI_MIN, comm2d, ierr )
656	#else
657	topo_min_level = MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
658	#endif
659
660	!
661	!-- Check topography for consistency with model domain. Therefore, use maximum and minium
662	!-- topography-top indices. Note, minimum topography top index is already calculated.
663	IF ( TRIM( topography ) /= 'flat' ) THEN
664	#if defined( __parallel )
665	CALL MPI_ALLREDUCE( MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), nzb_local_max, 1, &
666	MPI_INTEGER, MPI_MAX, comm2d, ierr )
667	#else
668	nzb_local_max = MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
669	#endif
670	nzb_local_min = topo_min_level
671	!
672	!-- Consistency checks
673	IF ( nzb_local_min < 0 .OR. nzb_local_max > nz + 1 ) THEN
674	WRITE( message_string, * ) 'nzb_local values are outside the model domain', &
675	'&MINVAL( nzb_local ) = ', nzb_local_min, &
676	'&MAXVAL( nzb_local ) = ', nzb_local_max
677	CALL message( 'init_grid', 'PA0210', 1, 2, 0, 6, 0 )
678	ENDIF
679	ENDIF
680	!
681	!-- Define vertical gridpoint from (or to) which on the usual finite difference form (which does not
682	!-- use surface fluxes) is applied.
683	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
684	nzb_diff = nzb + 2
685	ELSE
686	nzb_diff = nzb + 1
687	ENDIF
688
689	IF ( TRIM( topography ) /= 'flat' ) THEN
690	!
691	!-- Allocate and set the arrays containing the topography height (for output reasons only).
692	IF ( nxr == nx .AND. nyn /= ny ) THEN
693	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn), zw_w_inner(nxl:nxr+1,nys:nyn) )
694	ELSEIF ( nxr /= nx .AND. nyn == ny ) THEN
695	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn+1), zw_w_inner(nxl:nxr,nys:nyn+1) )
696	ELSEIF ( nxr == nx .AND. nyn == ny ) THEN
697	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn+1), zw_w_inner(nxl:nxr+1,nys:nyn+1) )
698	ELSE
699	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn), zw_w_inner(nxl:nxr,nys:nyn) )
700	ENDIF
701
702	zu_s_inner = 0.0_wp
703	zw_w_inner = 0.0_wp
704	!
705	!-- Determine local topography height on scalar and w-grid. Note, setting lateral boundary values
706	!-- is not necessary, realized via wall_flags_static_0 array. Further, please note that loop
707	!-- bounds are different from nxl to nxr and nys to nyn on south and right model boundary, hence,
708	!-- use intrinsic lbound and ubound functions to infer array bounds.
709	DO i = LBOUND(zu_s_inner, 1), UBOUND(zu_s_inner, 1)
710	DO j = LBOUND(zu_s_inner, 2), UBOUND(zu_s_inner, 2)
711	!
712	!-- Topography height on scalar grid. Therefore, determine index of upward-facing surface
713	!-- element on scalar grid.
714	zu_s_inner(i,j) = zu(topo_top_ind(j,i,0))
715	!
716	!-- Topography height on w grid. Therefore, determine index of upward-facing surface
717	!-- element on w grid.
718	zw_w_inner(i,j) = zw(topo_top_ind(j,i,3))
719	ENDDO
720	ENDDO
721	ENDIF
722
723	END SUBROUTINE init_grid
724
725
726	! Description:
727	! -------------------------------------------------------------------------------------------------!
728	!> Calculation of the stretching factor through an iterative method. Ideas were taken from the paper
729	!> "Regional stretched grid generation and its application to the NCAR RegCM (1999)". Normally, no
730	!> analytic solution exists because the system of equations has two variables (r,l) but four
731	!> requirements (l=integer, r=[0,88;1,2], Eq(6), Eq(5) starting from index j=1) which results into
732	!> an overdetermined system.
733	!--------------------------------------------------------------------------------------------------!
734	SUBROUTINE calculate_stretching_factor( number_end )
735
736	USE control_parameters, &
737	ONLY: dz, dz_stretch_factor_array, dz_stretch_level_end, dz_stretch_level_start, &
738	message_string
739
740	USE kinds
741
742	IMPLICIT NONE
743
744	REAL(wp), PARAMETER :: stretch_factor_interval = 1.0E-06_wp !< interval for sampling possible stretching factors
745	REAL(wp), PARAMETER :: stretch_factor_lower_limit = 0.88_wp !< lowest possible stretching factor
746	REAL(wp), PARAMETER :: stretch_factor_upper_limit = 1.12_wp !< highest possible stretching factor
747
748	INTEGER(iwp) :: iterations !< number of iterations until stretch_factor_lower/upper_limit is reached
749	INTEGER(iwp) :: l_rounded !< after l_rounded grid levels dz(n) is strechted to dz(n+1) with stretch_factor_2
750	INTEGER(iwp) :: n !< loop variable for stretching
751
752	INTEGER(iwp), INTENT(IN) :: number_end !< number of user-specified end levels for stretching
753
754	REAL(wp) :: delta_l !< absolute difference between l and l_rounded
755	REAL(wp) :: delta_stretch_factor !< absolute difference between stretch_factor_1 and stretch_factor_2
756	REAL(wp) :: delta_total_new !< sum of delta_l and delta_stretch_factor for the next iteration (should be as small as
757	!< possible)
758	REAL(wp) :: delta_total_old !< sum of delta_l and delta_stretch_factor for the last iteration
759	REAL(wp) :: distance !< distance between dz_stretch_level_start and dz_stretch_level_end (stretching region)
760	REAL(wp) :: l !< value that fulfil Eq. (5) in the paper mentioned above together with stretch_factor_1
761	!< exactly
762	REAL(wp) :: numerator !< numerator of the quotient
763	REAL(wp) :: stretch_factor_1 !< stretching factor that fulfil Eq. (5) togehter with l exactly
764	REAL(wp) :: stretch_factor_2 !< stretching factor that fulfil Eq. (6) togehter with l_rounded exactly
765
766	REAL(wp) :: dz_stretch_factor_array_2(9) = 1.08_wp !< Array that contains all stretch_factor_2 that belongs to
767	!< stretch_factor_1
768
769
770	l = 0
771	DO n = 1, number_end
772
773	iterations = 1
774	stretch_factor_1 = 1.0_wp
775	stretch_factor_2 = 1.0_wp
776	delta_total_old = 1.0_wp
777
778	!
779	!-- First branch for stretching from rough to fine
780	IF ( dz(n) > dz(n+1) ) THEN
781	DO WHILE ( stretch_factor_1 >= stretch_factor_lower_limit )
782
783	stretch_factor_1 = 1.0_wp - iterations * stretch_factor_interval
784	distance = ABS( dz_stretch_level_end(n) - dz_stretch_level_start(n) )
785	numerator = distance * stretch_factor_1 / dz(n) + stretch_factor_1 - distance / dz(n)
786
787	IF ( numerator > 0.0_wp ) THEN
788	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0_wp
789	l_rounded = NINT( l )
790	delta_l = ABS( l_rounded - l ) / l
791	ENDIF
792
793	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
794
795	delta_stretch_factor = ABS( stretch_factor_1 - stretch_factor_2 ) / stretch_factor_2
796
797	delta_total_new = delta_l + delta_stretch_factor
798
799	!
800	!-- stretch_factor_1 is taken to guarantee that the stretching procedure ends as close as
801	!-- possible to dz_stretch_level_end.
802	!-- stretch_factor_2 would guarantee that the stretched dz(n) is equal to dz(n+1) after
803	!-- l_rounded grid levels.
804	IF (delta_total_new < delta_total_old) THEN
805	dz_stretch_factor_array(n) = stretch_factor_1
806	dz_stretch_factor_array_2(n) = stretch_factor_2
807	delta_total_old = delta_total_new
808	ENDIF
809
810	iterations = iterations + 1
811
812	ENDDO
813
814	!
815	!-- Second branch for stretching from fine to rough
816	ELSEIF ( dz(n) < dz(n+1) ) THEN
817	DO WHILE ( stretch_factor_1 <= stretch_factor_upper_limit )
818
819	stretch_factor_1 = 1.0_wp + iterations * stretch_factor_interval
820	distance = ABS( dz_stretch_level_end(n) - dz_stretch_level_start(n) )
821	numerator = distance * stretch_factor_1 / dz(n) + stretch_factor_1 - distance / dz(n)
822
823	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0_wp
824	l_rounded = NINT( l )
825	delta_l = ABS( l_rounded - l ) / l
826
827	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
828
829	delta_stretch_factor = ABS( stretch_factor_1 - stretch_factor_2 ) / stretch_factor_2
830
831	delta_total_new = delta_l + delta_stretch_factor
832
833	!
834	!-- stretch_factor_1 is taken to guarantee that the stretching procedure ends as close as
835	!-- possible to dz_stretch_level_end.
836	!-- stretch_factor_2 would guarantee that the stretched dz(n) is equal to dz(n+1) after
837	!-- l_rounded grid levels.
838	IF (delta_total_new < delta_total_old) THEN
839	dz_stretch_factor_array(n) = stretch_factor_1
840	dz_stretch_factor_array_2(n) = stretch_factor_2
841	delta_total_old = delta_total_new
842	ENDIF
843
844	iterations = iterations + 1
845	ENDDO
846
847	ELSE
848	message_string= 'Two adjacent values of dz must be different'
849	CALL message( 'init_grid', 'PA0228', 1, 2, 0, 6, 0 )
850
851	ENDIF
852
853	!
854	!-- Check if also the second stretching factor fits into the allowed interval. If not, print a
855	!-- warning for the user.
856	IF ( dz_stretch_factor_array_2(n) < stretch_factor_lower_limit .OR. &
857	dz_stretch_factor_array_2(n) > stretch_factor_upper_limit ) THEN
858	WRITE( message_string, * ) 'stretch_factor_2 = ', dz_stretch_factor_array_2(n), &
859	' which is', ' responsible for exactly reaching& dz =', &
860	dz(n+1), 'after a specific amount of', &
861	' grid levels& exceeds the upper', &
862	' limit =', stretch_factor_upper_limit, &
863	' &or lower limit = ', stretch_factor_lower_limit
864	CALL message( 'init_grid', 'PA0499', 0, 1, 0, 6, 0 )
865
866	ENDIF
867	ENDDO
868
869	END SUBROUTINE calculate_stretching_factor
870
871
872	! Description:
873	! -------------------------------------------------------------------------------------------------!
874	!> Set temporary topography flags and reference buildings on top of underlying orography.
875	!--------------------------------------------------------------------------------------------------!
876	SUBROUTINE process_topography( topo_3d )
877
878	USE arrays_3d, &
879	ONLY: zu, zw
880
881	USE control_parameters, &
882	ONLY: bc_lr_cyc, bc_ns_cyc, ocean_mode
883
884	USE exchange_horiz_mod, &
885	ONLY: exchange_horiz_2d, exchange_horiz_int
886
887	USE indices, &
888	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt
889
890	USE netcdf_data_input_mod, &
891	ONLY: buildings_f, building_id_f, building_type_f, &
892	init_model, &
893	input_pids_static, &
894	terrain_height_f
895
896	USE kinds
897
898	USE pegrid
899
900	IMPLICIT NONE
901
902	INTEGER(iwp) :: i !< running index along x-direction
903	INTEGER(iwp) :: j !< running index along y-direction
904	INTEGER(iwp) :: k !< running index along z-direction with respect to numeric grid
905	INTEGER(iwp) :: k2 !< running index along z-direction with respect to netcdf grid
906	INTEGER(iwp) :: nr !< index variable indication maximum terrain height for respective building ID
907	INTEGER(iwp) :: num_build !< counter for number of buildings
908	INTEGER(iwp) :: topo_top_index !< orography top index, used to map 3D buildings onto terrain
909
910	#if defined( __parallel )
911	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displace_dum !< displacements of start addresses, used for MPI_ALLGATHERV
912	#endif
913	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids !< building IDs on entire model domain
914	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final !< building IDs on entire model domain, multiple occurences are
915	!< sorted out
916	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final_tmp !< temporary array used for resizing
917	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l !< building IDs on local subdomain
918	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l_tmp !< temporary array used to resize array of building IDs
919
920	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings !< number of buildings with different ID on entire model domain
921	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings_l !< number of buildings with different ID on local subdomain
922
923	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< input array for 3D topography and dummy array for setting
924	!< "outer"-flags
925
926	REAL(wp) :: ocean_offset !< offset to consider inverse vertical coordinate at topography
927	!< definition
928	REAL(wp) :: oro_min = 0.0_wp !< minimum terrain height in entire model domain, used to reference
929	!< terrain to zero
930	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max !< maximum terrain height occupied by an building with certain id
931	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max_l !< maximum terrain height occupied by an building with certain id,
932	!< on local subdomain
933
934	!
935	!-- Reference lowest terrain height to zero. This ensures that first, non-required gird levels
936	!-- (those which lie entirely below the minimum orography) are avoided, and second, that also
937	!-- negative orography can be used within the input file.
938	!-- Please note, in case of a nested run, the global minimum from all parent and childs needs to be
939	!-- removed to avoid steep edges at the child-domain boundaries.
940	IF ( input_pids_static ) THEN
941
942	#if defined( __parallel )
943	CALL MPI_ALLREDUCE( MINVAL( terrain_height_f%var ), oro_min, 1, MPI_REAL, MPI_MIN, &
944	MPI_COMM_WORLD, ierr )
945	#else
946	oro_min = MINVAL( terrain_height_f%var )
947	#endif
948	terrain_height_f%var = terrain_height_f%var - oro_min
949	!
950	!-- Update reference height used within output files
951	init_model%origin_z = init_model%origin_z + oro_min
952
953	ENDIF
954
955	!
956	!-- In the following, buildings and orography are further preprocessed before they are mapped on the
957	!-- LES grid.
958	!-- Buildings are mapped on top of the orography by maintaining the roof shape of the building. This
959	!-- can be achieved by referencing building on top of the maximum terrain height within the area
960	!-- occupied by the respective building. As buildings and terrain height are defined PE-wise,
961	!-- parallelization of this referencing is required (a building can be distributed between different
962	!-- PEs).
963	!-- In a first step, determine the number of buildings with different building id on each PE. In a
964	!-- next step, all building ids are gathered into one array which is present to all PEs. For each
965	!-- building ID, the maximum terrain height occupied by the respective building is computed and
966	!-- distributed to each PE.
967	!-- Finally, for each building id and its respective reference orography, builidings are mapped on
968	!-- top.
969	!--
970	!-- First, pre-set topography flags, bit 1 indicates orography, bit 2 buildings classify the
971	!-- respective surfaces.
972	topo_3d = IBSET( topo_3d, 0 )
973	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
974	!
975	!-- In order to map topography on PALM grid also in case of ocean simulations, pre-calculate an
976	!-- offset value.
977	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
978	!
979	!-- Reference buildings on top of orography. This is not necessary if topography is read from ASCII
980	!-- file as no distinction between buildings and terrain height can be made. Moreover, this is also
981	!-- not necessary if urban-surface and land-surface model are used at the same time.
982	IF ( input_pids_static ) THEN
983
984	IF ( buildings_f%from_file ) THEN
985	num_buildings_l = 0
986	num_buildings = 0
987	!
988	!-- Allocate at least one element for building ids and give it an inital negative value that
989	!-- will be overwritten later. This, however, is necessary in case there all IDs in the model
990	!-- domain are fill values.
991	ALLOCATE( build_ids_l(1) )
992	build_ids_l = -1
993	DO i = nxl, nxr
994	DO j = nys, nyn
995	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
996	IF ( num_buildings_l(myid) > 0 ) THEN
997	IF ( ANY( building_id_f%var(j,i) == build_ids_l ) ) THEN
998	CYCLE
999	ELSE
1000	num_buildings_l(myid) = num_buildings_l(myid) + 1
1001	!
1002	!-- Resize array with different local building ids
1003	ALLOCATE( build_ids_l_tmp(1:SIZE(build_ids_l)) )
1004	build_ids_l_tmp = build_ids_l
1005	DEALLOCATE( build_ids_l )
1006	ALLOCATE( build_ids_l(1:num_buildings_l(myid)) )
1007	build_ids_l(1:num_buildings_l(myid)-1) = &
1008	build_ids_l_tmp(1:num_buildings_l(myid)-1)
1009	build_ids_l(num_buildings_l(myid)) = building_id_f%var(j,i)
1010	DEALLOCATE( build_ids_l_tmp )
1011	ENDIF
1012	!
1013	!-- First occuring building id on PE
1014	ELSE
1015	num_buildings_l(myid) = num_buildings_l(myid) + 1
1016	build_ids_l(1) = building_id_f%var(j,i)
1017	ENDIF
1018	ENDIF
1019	ENDDO
1020	ENDDO
1021	!
1022	!-- Determine number of different building ids for the entire domain
1023	#if defined( __parallel )
1024	CALL MPI_ALLREDUCE( num_buildings_l, num_buildings, numprocs, MPI_INTEGER, MPI_SUM, &
1025	comm2d, ierr )
1026	#else
1027	num_buildings = num_buildings_l
1028	#endif
1029	!
1030	!-- Gather all buildings ids on each PEs.
1031	!-- First, allocate array encompassing all building ids in model domain.
1032	ALLOCATE( build_ids(1:SUM(num_buildings)) )
1033	#if defined( __parallel )
1034	!
1035	!-- Allocate array for displacements.
1036	!-- As each PE may has a different number of buildings, so that the block sizes send by each
1037	!-- PE may not be equal. Hence, information about the respective displacement is required,
1038	!-- indicating the respective adress where each MPI-task writes into the receive buffer array.
1039	ALLOCATE( displace_dum(0:numprocs-1) )
1040	displace_dum(0) = 0
1041	DO i = 1, numprocs-1
1042	displace_dum(i) = displace_dum(i-1) + num_buildings(i-1)
1043	ENDDO
1044
1045	CALL MPI_ALLGATHERV( build_ids_l(1:num_buildings_l(myid)), num_buildings(myid), &
1046	MPI_INTEGER, build_ids, num_buildings, displace_dum, MPI_INTEGER, &
1047	comm2d, ierr )
1048
1049	DEALLOCATE( displace_dum )
1050
1051	#else
1052	build_ids = build_ids_l
1053	#endif
1054
1055	!
1056	!-- Note, in parallel mode building ids can occure mutliple times, as each PE has send its own
1057	!-- ids. Therefore, sort out building ids which appear more than one time.
1058	num_build = 0
1059	DO nr = 1, SIZE(build_ids)
1060
1061	IF ( ALLOCATED(build_ids_final) ) THEN
1062	IF ( ANY( build_ids(nr) == build_ids_final ) ) THEN
1063	CYCLE
1064	ELSE
1065	num_build = num_build + 1
1066	!
1067	!-- Resize
1068	ALLOCATE( build_ids_final_tmp(1:num_build) )
1069	build_ids_final_tmp(1:num_build-1) = build_ids_final(1:num_build-1)
1070	DEALLOCATE( build_ids_final )
1071	ALLOCATE( build_ids_final(1:num_build) )
1072	build_ids_final(1:num_build-1) = build_ids_final_tmp(1:num_build-1)
1073	build_ids_final(num_build) = build_ids(nr)
1074	DEALLOCATE( build_ids_final_tmp )
1075	ENDIF
1076	ELSE
1077	num_build = num_build + 1
1078	ALLOCATE( build_ids_final(1:num_build) )
1079	build_ids_final(num_build) = build_ids(nr)
1080	ENDIF
1081	ENDDO
1082
1083	!
1084	!-- Determine maximumum terrain height occupied by the respective building and temporalily
1085	!-- store on oro_max.
1086	ALLOCATE( oro_max_l(1:SIZE(build_ids_final)) )
1087	ALLOCATE( oro_max(1:SIZE(build_ids_final)) )
1088	oro_max_l = 0.0_wp
1089
1090	DO nr = 1, SIZE(build_ids_final)
1091	oro_max_l(nr) = MAXVAL( MERGE( terrain_height_f%var(nys:nyn,nxl:nxr), &
1092	0.0_wp, &
1093	building_id_f%var(nys:nyn,nxl:nxr) == &
1094	build_ids_final(nr) ) )
1095	ENDDO
1096
1097	#if defined( __parallel )
1098	IF ( SIZE(build_ids_final) >= 1 ) THEN
1099	CALL MPI_ALLREDUCE( oro_max_l, oro_max, SIZE( oro_max ), MPI_REAL, MPI_MAX, comm2d, &
1100	ierr )
1101	ENDIF
1102	#else
1103	oro_max = oro_max_l
1104	#endif
1105	!
1106	!-- Finally, determine discrete grid height of maximum orography occupied by a building. Use
1107	!-- all-or-nothing approach, i.e. if terrain exceeds the scalar level the grid box is fully
1108	!-- terrain and the maximum terrain is set to the zw level.
1109	!-- terrain or
1110	oro_max_l = 0.0
1111	DO nr = 1, SIZE(build_ids_final)
1112	DO k = nzb, nzt
1113	IF ( zu(k) - ocean_offset <= oro_max(nr) ) oro_max_l(nr) = zw(k) - ocean_offset
1114	ENDDO
1115	oro_max(nr) = oro_max_l(nr)
1116	ENDDO
1117	ENDIF
1118	!
1119	!-- Allocate array for storing terrain height under buildings
1120	IF ( buildings_f%from_file ) THEN
1121	ALLOCATE( buildings_f%oro_max(nysg:nyng,nxlg:nxrg) )
1122	buildings_f%oro_max = buildings_f%fill1
1123	END IF
1124	!
1125	!-- Map orography as well as buildings onto grid.
1126	DO i = nxl, nxr
1127	DO j = nys, nyn
1128	topo_top_index = 0
1129	!
1130	!-- Obtain index in global building_id array
1131	IF ( buildings_f%from_file ) THEN
1132	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1133	!
1134	!-- Determine index where maximum terrain height occupied by the respective building
1135	!-- height is stored.
1136	nr = MINLOC( ABS( build_ids_final - building_id_f%var(j,i) ), DIM=1 )
1137	!
1138	!-- Save grid-indexed oro_max
1139	buildings_f%oro_max(j,i) = oro_max(nr)
1140	ENDIF
1141	ENDIF
1142	DO k = nzb, nzt
1143	!
1144	!-- In a first step, if grid point is below or equal the given terrain height, grid
1145	!-- point is flagged to be of type natural.
1146	!-- Please note, in case there is also a building which is lower than the vertical grid
1147	!-- spacing, initialization of surface attributes will not be correct as given surface
1148	!-- information will not be in accordance to the classified grid points.
1149	!-- Hence, in this case, also a building flag.
1150	IF ( zu(k) - ocean_offset <= terrain_height_f%var(j,i) ) THEN
1151	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1152	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1153	topo_top_index = k ! topo_top_index + 1
1154	ENDIF
1155	!
1156	!-- Set building grid points. Here, only consider 2D buildings.
1157	!-- 3D buildings require separate treatment.
1158	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1159	!
1160	!-- Fill-up the terrain to the level of maximum orography within the building-covered
1161	!-- area.
1162	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1163	!
1164	!-- Note, oro_max is always on zw level
1165	IF ( zu(k) - ocean_offset < oro_max(nr) ) THEN
1166	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1167	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1168	ELSEIF ( zu(k) - ocean_offset <= oro_max(nr) + buildings_f%var_2d(j,i) ) THEN
1169	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1170	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1171	ENDIF
1172	ENDIF
1173	ENDIF
1174	ENDDO
1175	!
1176	!-- Special treatment for non grid-resolved buildings. This case, the uppermost terrain
1177	!-- grid point is flagged as building as well, even though no building exists at all.
1178	!-- However, the surface element will be identified as urban-surface and the input data
1179	!-- provided by the drivers is consistent to the surface classification. Else, all non
1180	!-- grid-resolved buildings would vanish and identified as terrain grid points, which,
1181	!-- however, won't be consistent with the input data.
1182	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1183	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1184	DO k = nzb, nzt
1185	IF( zw(k) - ocean_offset == oro_max(nr) ) THEN
1186	IF ( buildings_f%var_2d(j,i) <= zu(k+1) - zw(k) ) THEN
1187	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1188	ENDIF
1189	ENDIF
1190	ENDDO
1191	ENDIF
1192	ENDIF
1193	!
1194	!-- Map 3D buildings onto terrain height.
1195	!-- In case of any slopes, map building on top of maximum terrain height covered by the
1196	!-- building. In other words, extend building down to the respective local terrain-surface
1197	!-- height.
1198	IF ( buildings_f%from_file .AND. buildings_f%lod == 2 ) THEN
1199	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1200	!
1201	!-- Extend building down to the terrain surface, i.e. fill-up surface irregularities
1202	!-- below a building. Note, oro_max is already a discrete height according to the
1203	!-- all-or-nothing approach, i.e. grid box is either topography or atmosphere,
1204	!-- terrain top is defined at upper bound of the grid box.
1205	!-- Hence, check for zw in this case.
1206	!-- Note, do this only for buildings which are surface mounted, i.e. building types
1207	!-- 1-6. Below bridges, which are represented exclusively by building type 7, terrain
1208	!-- shape should be maintained.
1209	IF ( building_type_f%from_file ) THEN
1210	IF ( building_type_f%var(j,i) /= 7 ) THEN
1211	DO k = topo_top_index + 1, nzt + 1
1212	IF ( zu(k) - ocean_offset <= oro_max(nr) ) THEN
1213	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1214	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1215	ENDIF
1216	ENDDO
1217	!
1218	!-- After surface irregularities are smoothen, determine lower start index
1219	!-- where building starts.
1220	DO k = nzb, nzt
1221	IF ( zu(k) - ocean_offset <= oro_max(nr) ) topo_top_index = k
1222	ENDDO
1223	ENDIF
1224	ENDIF
1225	!
1226	!-- Finally, map building on top.
1227	k2 = 0
1228	DO k = topo_top_index, nzt + 1
1229	IF ( k2 <= buildings_f%nz-1 ) THEN
1230	IF ( buildings_f%var_3d(k2,j,i) == 1 ) THEN
1231	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1232	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1233	ENDIF
1234	ENDIF
1235	k2 = k2 + 1
1236	ENDDO
1237	ENDIF
1238	ENDIF
1239	ENDDO
1240	ENDDO
1241	!
1242	!-- Horizontal exchange the oro_max array, which is required to for initialization of
1243	!-- building-surface properties.
1244	IF ( ALLOCATED( buildings_f%oro_max ) ) THEN
1245	CALL exchange_horiz_2d( buildings_f%oro_max(:,:) )
1246	ENDIF
1247	!
1248	!-- Deallocate temporary arrays required for processing and reading data
1249	IF ( ALLOCATED( oro_max ) ) DEALLOCATE( oro_max )
1250	IF ( ALLOCATED( oro_max_l ) ) DEALLOCATE( oro_max_l )
1251	IF ( ALLOCATED( build_ids_final ) ) DEALLOCATE( build_ids_final )
1252	!
1253	!-- Topography input via ASCII format.
1254	ELSE
1255	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1256	!
1257	!-- Initialize topography bit 0 (indicates obstacle) everywhere to zero and clear all grid points
1258	!-- at nzb, where alway a surface is defined.
1259	!-- Further, set also bit 1 (indicates terrain) at nzb, which is further used for masked data
1260	!-- output and further processing. Note, in the ASCII case no distinction is made between
1261	!-- buildings and terrain, so that setting of bit 1 and 2 at the same time has no effect.
1262	topo_3d = IBSET( topo_3d, 0 )
1263	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1264	topo_3d(nzb,:,:) = IBSET( topo_3d(nzb,:,:), 1 )
1265	DO i = nxl, nxr
1266	DO j = nys, nyn
1267	DO k = nzb, nzt
1268	!
1269	!-- Flag topography for all grid points which are below the local topography height.
1270	!-- Note, each topography is flagged as building (bit 2) as well as terrain (bit 1) in
1271	!-- order to employ urban-surface as well as land-surface model.
1272	IF ( zu(k) - ocean_offset <= buildings_f%var_2d(j,i) ) THEN
1273	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1274	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 1 )
1275	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1276	ENDIF
1277	ENDDO
1278	ENDDO
1279	ENDDO
1280	ENDIF
1281
1282	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1283
1284	IF ( .NOT. bc_ns_cyc ) THEN
1285	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1286	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1287	ENDIF
1288
1289	IF ( .NOT. bc_lr_cyc ) THEN
1290	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1291	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1292	ENDIF
1293
1294	END SUBROUTINE process_topography
1295
1296
1297	! Description:
1298	! -------------------------------------------------------------------------------------------------!
1299	!> Filter topography, i.e. fill holes resolved by only one grid point.
1300	!> Such holes are suspected to lead to velocity blow-ups as continuity equation on discrete grid
1301	!> cannot be fulfilled in such case.
1302	!--------------------------------------------------------------------------------------------------!
1303	SUBROUTINE filter_topography( topo_3d )
1304
1305	USE control_parameters, &
1306	ONLY: bc_lr_cyc, bc_ns_cyc, message_string
1307
1308	USE exchange_horiz_mod, &
1309	ONLY: exchange_horiz_int, exchange_horiz_2d_byte, exchange_horiz_2d_int
1310
1311	USE indices, &
1312	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt
1313
1314	USE netcdf_data_input_mod, &
1315	ONLY: building_id_f, building_type_f
1316
1317	USE pegrid
1318
1319	IMPLICIT NONE
1320
1321	INTEGER(iwp) :: i !< running index along x-direction
1322	INTEGER(iwp) :: j !< running index along y-direction
1323	INTEGER(iwp) :: k !< running index along z-direction
1324	INTEGER(iwp) :: num_hole !< number of holes (in topography) resolved by only one grid point
1325	INTEGER(iwp) :: num_hole_l !< number of holes (in topography) resolved by only one grid point on local PE
1326	INTEGER(iwp) :: num_wall !< number of surrounding vertical walls for a single grid point
1327
1328	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo_tmp !< temporary 3D-topography used to fill holes
1329	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< 3D-topography array merging buildings and
1330	!< orography
1331
1332	LOGICAL :: filled = .FALSE. !< flag indicating if holes were filled
1333
1334	!
1335	!-- Before checking for holes, set lateral boundary conditions for
1336	!-- topography. After hole-filling, boundary conditions must be set again.
1337	!-- Several iterations are performed, in order to fill holes which might
1338	!-- emerge by the filling-algorithm itself.
1339	ALLOCATE( topo_tmp(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
1340	topo_tmp = 0
1341
1342	num_hole = 99999
1343	DO WHILE ( num_hole > 0 )
1344
1345	num_hole = 0
1346	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1347	!
1348	!-- Exchange also building ID and type. Note, building_type is an one-byte variable.
1349	IF ( building_id_f%from_file ) &
1350	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1351	IF ( building_type_f%from_file ) &
1352	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1353
1354	topo_tmp = topo_3d
1355	!
1356	!-- In case of non-cyclic lateral boundaries, assume lateral boundary to be a solid wall. Thus,
1357	!-- intermediate spaces of one grid point between boundary and some topographic structure will be
1358	!-- filled.
1359	IF ( .NOT. bc_ns_cyc ) THEN
1360	IF ( nys == 0 ) topo_tmp(:,-1,:) = IBCLR( topo_tmp(:,0,:), 0 )
1361	IF ( nyn == ny ) topo_tmp(:,ny+1,:) = IBCLR( topo_tmp(:,ny,:), 0 )
1362	ENDIF
1363
1364	IF ( .NOT. bc_lr_cyc ) THEN
1365	IF ( nxl == 0 ) topo_tmp(:,:,-1) = IBCLR( topo_tmp(:,:,0), 0 )
1366	IF ( nxr == nx ) topo_tmp(:,:,nx+1) = IBCLR( topo_tmp(:,:,nx), 0 )
1367	ENDIF
1368
1369	num_hole_l = 0
1370	DO i = nxl, nxr
1371	DO j = nys, nyn
1372	DO k = nzb+1, nzt
1373	IF ( BTEST( topo_tmp(k,j,i), 0 ) ) THEN
1374	num_wall = 0
1375	IF ( .NOT. BTEST( topo_tmp(k,j-1,i), 0 ) ) num_wall = num_wall + 1
1376	IF ( .NOT. BTEST( topo_tmp(k,j+1,i), 0 ) ) num_wall = num_wall + 1
1377	IF ( .NOT. BTEST( topo_tmp(k,j,i-1), 0 ) ) num_wall = num_wall + 1
1378	IF ( .NOT. BTEST( topo_tmp(k,j,i+1), 0 ) ) num_wall = num_wall + 1
1379	IF ( .NOT. BTEST( topo_tmp(k-1,j,i), 0 ) ) num_wall = num_wall + 1
1380	IF ( .NOT. BTEST( topo_tmp(k+1,j,i), 0 ) ) num_wall = num_wall + 1
1381
1382	IF ( num_wall >= 4 ) THEN
1383	num_hole_l = num_hole_l + 1
1384	!
1385	!-- Clear flag 0 and set special flag ( bit 4) to indicate that new topography
1386	!-- point is a result of filtering process.
1387	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1388	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 4 )
1389	!
1390	!-- If filled grid point is occupied by a building, classify it as building grid
1391	!-- point.
1392	IF ( building_type_f%from_file ) THEN
1393	IF ( building_type_f%var(j,i) /= building_type_f%fill .OR. &
1394	building_type_f%var(j+1,i) /= building_type_f%fill .OR. &
1395	building_type_f%var(j-1,i) /= building_type_f%fill .OR. &
1396	building_type_f%var(j,i+1) /= building_type_f%fill .OR. &
1397	building_type_f%var(j,i-1) /= building_type_f%fill ) THEN
1398	!
1399	!-- Set flag indicating building surfaces
1400	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1401	!
1402	!-- Set building_type and ID at this position if not already set. This is
1403	!-- required for proper initialization of urban-surface energy balance
1404	!-- solver.
1405	IF ( building_type_f%var(j,i) == building_type_f%fill ) THEN
1406
1407	IF ( building_type_f%var(j+1,i) /= building_type_f%fill ) THEN
1408	building_type_f%var(j,i) = building_type_f%var(j+1,i)
1409	building_id_f%var(j,i) = building_id_f%var(j+1,i)
1410	ELSEIF ( building_type_f%var(j-1,i) /= building_type_f%fill ) THEN
1411	building_type_f%var(j,i) = building_type_f%var(j-1,i)
1412	building_id_f%var(j,i) = building_id_f%var(j-1,i)
1413	ELSEIF ( building_type_f%var(j,i+1) /= building_type_f%fill ) THEN
1414	building_type_f%var(j,i) = building_type_f%var(j,i+1)
1415	building_id_f%var(j,i) = building_id_f%var(j,i+1)
1416	ELSEIF ( building_type_f%var(j,i-1) /= building_type_f%fill ) THEN
1417	building_type_f%var(j,i) = building_type_f%var(j,i-1)
1418	building_id_f%var(j,i) = building_id_f%var(j,i-1)
1419	ENDIF
1420	ENDIF
1421	ENDIF
1422	ENDIF
1423	!
1424	!-- If filled grid point is already classified as building everything is fine,
1425	!-- else classify this grid point as natural type grid point. This case, values
1426	!-- for the surface type are already set.
1427	IF ( .NOT. BTEST( topo_3d(k,j,i), 2 ) ) THEN
1428	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1429	ENDIF
1430	ENDIF
1431	ENDIF
1432	ENDDO
1433	ENDDO
1434	ENDDO
1435	!
1436	!-- Count the total number of holes, required for informative message.
1437	#if defined( __parallel )
1438	CALL MPI_ALLREDUCE( num_hole_l, num_hole, 1, MPI_INTEGER, MPI_SUM, comm2d, ierr )
1439	#else
1440	num_hole = num_hole_l
1441	#endif
1442	IF ( num_hole > 0 .AND. .NOT. filled ) filled = .TRUE.
1443
1444	ENDDO
1445	!
1446	!-- Create an informative message if any holes were filled.
1447	IF ( filled ) THEN
1448	WRITE( message_string, * ) 'Topography was filtered, i.e. holes ' // &
1449	'resolved by only one grid point ' // &
1450	'were filled during initialization.'
1451	CALL message( 'init_grid', 'PA0430', 0, 0, 0, 6, 0 )
1452	ENDIF
1453
1454	DEALLOCATE( topo_tmp )
1455	!
1456	!-- Finally, exchange topo_3d array again and if necessary set Neumann boundary condition in case of
1457	!-- non-cyclic lateral boundaries.
1458	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1459
1460	IF ( .NOT. bc_ns_cyc ) THEN
1461	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1462	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1463	ENDIF
1464
1465	IF ( .NOT. bc_lr_cyc ) THEN
1466	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1467	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1468	ENDIF
1469	!
1470	!-- Exchange building ID and type. Note, building_type is an one-byte variable.
1471	IF ( building_id_f%from_file ) &
1472	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1473	IF ( building_type_f%from_file ) &
1474	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1475
1476	END SUBROUTINE filter_topography
1477
1478
1479	! Description:
1480	! -------------------------------------------------------------------------------------------------!
1481	!> Reads topography information from file or sets generic topography. Moreover, all
1482	!> topography-relevant topography arrays are initialized, and grid flags are set.
1483	!--------------------------------------------------------------------------------------------------!
1484	SUBROUTINE init_topo( topo )
1485
1486	USE arrays_3d, &
1487	ONLY: zw
1488
1489	USE control_parameters, &
1490	ONLY: bc_lr_cyc, bc_ns_cyc, building_height, building_length_x, building_length_y, &
1491	building_wall_left, building_wall_south, canyon_height, canyon_wall_left, &
1492	canyon_wall_south, canyon_width_x, canyon_width_y, dp_level_ind_b, dz, &
1493	message_string, topography, topography_grid_convention, tunnel_height, &
1494	tunnel_length, tunnel_width_x, tunnel_width_y, tunnel_wall_depth
1495
1496	USE exchange_horiz_mod, &
1497	ONLY: exchange_horiz_int
1498
1499	USE grid_variables, &
1500	ONLY: dx, dy
1501
1502	USE indices, &
1503	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, nzb, nzt
1504
1505	USE kinds
1506
1507	USE netcdf_data_input_mod, &
1508	ONLY: buildings_f, terrain_height_f
1509
1510	USE pegrid
1511
1512	IMPLICIT NONE
1513
1514	INTEGER(iwp) :: bh !< temporary vertical index of building height
1515	INTEGER(iwp) :: ch !< temporary vertical index for canyon height
1516	INTEGER(iwp) :: hv_in !< heavyside function to model inner tunnel surface
1517	INTEGER(iwp) :: i !< index variable along x
1518	INTEGER(iwp) :: index_left_bwall !< index for left building wall
1519	INTEGER(iwp) :: index_north_bwall !< index for north building wall
1520	INTEGER(iwp) :: index_right_bwall !< index for right building wall
1521	INTEGER(iwp) :: index_south_bwall !< index for south building wall
1522	INTEGER(iwp) :: index_left_cwall !< index for left canyon wall
1523	INTEGER(iwp) :: index_north_cwall !< index for north canyon wall
1524	INTEGER(iwp) :: index_right_cwall !< index for right canyon wall
1525	INTEGER(iwp) :: index_south_cwall !< index for south canyon wall
1526	INTEGER(iwp) :: j !< index variable along y
1527	INTEGER(iwp) :: k !< index variable along z
1528	INTEGER(iwp) :: ngp_bx !< grid point number of building size along x
1529	INTEGER(iwp) :: ngp_by !< grid point number of building size along y
1530	INTEGER(iwp) :: ngp_cx !< grid point number of canyon size along x
1531	INTEGER(iwp) :: ngp_cy !< grid point number of canyon size along y
1532	INTEGER(iwp) :: hv_out !< heavyside function to model outer tunnel surface
1533	INTEGER(iwp) :: td !< tunnel wall depth
1534	INTEGER(iwp) :: th !< height of outer tunnel wall
1535	INTEGER(iwp) :: txe_in !< end position of inner tunnel wall in x
1536	INTEGER(iwp) :: txe_out !< end position of outer tunnel wall in x
1537	INTEGER(iwp) :: txs_in !< start position of inner tunnel wall in x
1538	INTEGER(iwp) :: txs_out !< start position of outer tunnel wall in x
1539	INTEGER(iwp) :: tye_in !< end position of inner tunnel wall in y
1540	INTEGER(iwp) :: tye_out !< end position of outer tunnel wall in y
1541	INTEGER(iwp) :: tys_in !< start position of inner tunnel wall in y
1542	INTEGER(iwp) :: tys_out !< start position of outer tunnel wall in y
1543
1544	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
1545	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting
1546	!< "outer"-flags
1547	!
1548	!-- Check for correct setting of the namelist parameter topography. If topography information is
1549	!-- read from file but topography = 'flat', initialization does not work properly.
1550	IF ( ( buildings_f%from_file .OR. terrain_height_f%from_file ) .AND. &
1551	TRIM( topography ) /= 'read_from_file' ) THEN
1552	message_string = 'If topography information is provided (via ' // &
1553	'Netcdf or ASCII input) topography = ' // &
1554	'"read_from_file" is required.'
1555	CALL message( 'init_grid', 'PA0437', 1, 2, 0, 6, 0 )
1556	ENDIF
1557	!
1558	!-- Set outer and inner index arrays for non-flat topography.
1559	!-- Here consistency checks concerning domain size and periodicity are necessary.
1560	!-- Within this SELECT CASE structure only nzb_local is initialized individually depending on the
1561	!-- chosen topography type, all other index arrays are initialized further below.
1562	SELECT CASE ( TRIM( topography ) )
1563
1564	CASE ( 'flat' )
1565	!
1566	!-- Initialilize 3D topography array, used later for initializing flags
1567	topo(nzb+1:nzt+1,:,:) = IBSET( topo(nzb+1:nzt+1,:,:), 0 )
1568
1569	CASE ( 'closed_channel' )
1570	!
1571	!-- Initialilize 3D topography array, used later for initializing flags
1572	topo(nzb+1:nzt,:,:) = IBSET( topo(nzb+1:nzt,:,:), 0 )
1573
1574	CASE ( 'single_building' )
1575	!
1576	!-- Single rectangular building, by default centered in the middle of the
1577	!-- total domain
1578	ngp_bx = NINT( building_length_x / dx )
1579	ngp_by = NINT( building_length_y / dy )
1580	bh = MINLOC( ABS( zw - building_height ), 1 ) - 1
1581	IF ( ABS( zw(bh) - building_height ) == ABS( zw(bh+1) - building_height ) ) bh = bh + 1
1582	IF ( building_wall_left == 9999999.9_wp ) THEN
1583	building_wall_left = ( nx + 1 - ngp_bx ) / 2 * dx
1584	ENDIF
1585	index_left_bwall = NINT( building_wall_left / dx )
1586	index_right_bwall = index_left_bwall + ngp_bx
1587
1588	IF ( building_wall_south == 9999999.9_wp ) THEN
1589	building_wall_south = ( ny + 1 - ngp_by ) / 2 * dy
1590	ENDIF
1591	index_south_bwall = NINT( building_wall_south / dy )
1592	index_north_bwall = index_south_bwall + ngp_by
1593
1594	!
1595	!-- Building size has to meet some requirements
1596	IF ( ( index_left_bwall < 1 ) .OR. ( index_right_bwall > nx-1 ) .OR. &
1597	( index_right_bwall < index_left_bwall+3 ) .OR. &
1598	( index_south_bwall < 1 ) .OR. ( index_north_bwall > ny-1 ) .OR. &
1599	( index_north_bwall < index_south_bwall+3 ) ) THEN
1600	WRITE( message_string, * ) 'inconsistent building parameters:', &
1601	'&index_left_bwall=', index_left_bwall, &
1602	'index_right_bwall=', index_right_bwall, &
1603	'index_south_bwall=', index_south_bwall, &
1604	'index_north_bwall=', index_north_bwall, &
1605	'nx=', nx, 'ny=', ny
1606	CALL message( 'init_grid', 'PA0203', 1, 2, 0, 6, 0 )
1607	ENDIF
1608
1609	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1610	nzb_local = 0
1611	!
1612	!-- Define the building.
1613	IF ( index_left_bwall <= nxr .AND. index_right_bwall >= nxl .AND. &
1614	index_south_bwall <= nyn .AND. index_north_bwall >= nys ) &
1615	nzb_local(MAX(nys,index_south_bwall):MIN(nyn,index_north_bwall), &
1616	MAX(nxl,index_left_bwall):MIN(nxr,index_right_bwall)) = bh
1617	!
1618	!-- Set bit array on basis of nzb_local
1619	DO i = nxl, nxr
1620	DO j = nys, nyn
1621	topo(nzb_local(j,i)+1:nzt+1,j,i) = IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1622	ENDDO
1623	ENDDO
1624
1625	DEALLOCATE( nzb_local )
1626
1627	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1628	!
1629	!-- Set boundary conditions also for flags. Can be interpreted as Neumannb oundary conditions
1630	!-- for topography.
1631	IF ( .NOT. bc_ns_cyc ) THEN
1632	IF ( nys == 0 ) THEN
1633	DO i = 1, nbgp
1634	topo(:,nys-i,:) = topo(:,nys,:)
1635	ENDDO
1636	ENDIF
1637	IF ( nyn == ny ) THEN
1638	DO i = 1, nbgp
1639	topo(:,nyn+i,:) = topo(:,nyn,:)
1640	ENDDO
1641	ENDIF
1642	ENDIF
1643	IF ( .NOT. bc_lr_cyc ) THEN
1644	IF ( nxl == 0 ) THEN
1645	DO i = 1, nbgp
1646	topo(:,:,nxl-i) = topo(:,:,nxl)
1647	ENDDO
1648	ENDIF
1649	IF ( nxr == nx ) THEN
1650	DO i = 1, nbgp
1651	topo(:,:,nxr+i) = topo(:,:,nxr)
1652	ENDDO
1653	ENDIF
1654	ENDIF
1655
1656	CASE ( 'single_street_canyon' )
1657	!
1658	!-- Single quasi-2D street canyon of infinite length in x or y direction.
1659	!-- The canyon is centered in the other direction by default.
1660	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1661	!
1662	!-- Street canyon in y direction
1663	ngp_cx = NINT( canyon_width_x / dx )
1664	IF ( canyon_wall_left == 9999999.9_wp ) THEN
1665	canyon_wall_left = ( nx + 1 - ngp_cx ) / 2 * dx
1666	ENDIF
1667	index_left_cwall= NINT( canyon_wall_left / dx )
1668	index_right_cwall= index_left_cwall+ ngp_cx
1669	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1670	!
1671	!-- Street canyon in x direction
1672	ngp_cy = NINT( canyon_width_y / dy )
1673	IF ( canyon_wall_south == 9999999.9_wp ) THEN
1674	canyon_wall_south = ( ny + 1 - ngp_cy ) / 2 * dy
1675	ENDIF
1676	index_south_cwall = NINT( canyon_wall_south / dy )
1677	index_north_cwall = index_south_cwall + ngp_cy
1678
1679	ELSE
1680
1681	message_string = 'no street canyon width given'
1682	CALL message( 'init_grid', 'PA0204', 1, 2, 0, 6, 0 )
1683
1684	ENDIF
1685
1686	ch = MINLOC( ABS( zw - canyon_height ), 1 ) - 1
1687	IF ( ABS( zw(ch) - canyon_height ) == ABS( zw(ch+1) - canyon_height ) ) ch = ch + 1
1688	dp_level_ind_b = ch
1689	!
1690	!-- Street canyon size has to meet some requirements
1691	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1692	IF ( ( index_left_cwall< 1 ) .OR. ( index_right_cwall> nx-1 ) .OR. &
1693	( ngp_cx < 3 ) ) THEN
1694	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1695	'&index_left_cwall=', index_left_cwall, &
1696	' index_right_cwall=', index_right_cwall, &
1697	' ngp_cx=', ngp_cx, ' ch=', ch, ' nx=', nx, ' ny=', ny
1698	CALL message( 'init_grid', 'PA0205', 1, 2, 0, 6, 0 )
1699	ENDIF
1700	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1701	IF ( ( index_south_cwall < 1 ) .OR. &
1702	( index_north_cwall > ny-1 ) .OR. ( ngp_cy < 3 ) ) THEN
1703	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1704	'&index_south_cwall=', index_south_cwall, &
1705	' index_north_cwall=', index_north_cwall, &
1706	' ngp_cy=', ngp_cy, ' ch=', ch, ' nx=', nx, ' ny=', ny
1707	CALL message( 'init_grid', 'PA0206', 1, 2, 0, 6, 0 )
1708	ENDIF
1709	ENDIF
1710	IF ( canyon_width_x /= 9999999.9_wp .AND. canyon_width_y /= 9999999.9_wp ) THEN
1711	message_string = 'inconsistent canyon parameters:' // &
1712	'&street canyon can only be oriented' // &
1713	' either in x- or in y-direction'
1714	CALL message( 'init_grid', 'PA0207', 1, 2, 0, 6, 0 )
1715	ENDIF
1716
1717	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1718	nzb_local = ch
1719	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1720	IF ( index_left_cwall<= nxr .AND. index_right_cwall>= nxl ) &
1721	nzb_local(:,MAX(nxl,index_left_cwall+1):MIN(nxr,index_right_cwall-1)) = 0
1722	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1723	IF ( index_south_cwall <= nyn .AND. index_north_cwall >= nys ) &
1724	nzb_local(MAX(nys,index_south_cwall+1):MIN(nyn,index_north_cwall-1),:) = 0
1725	ENDIF
1726	!
1727	!-- Set bit array on basis of nzb_local
1728	DO i = nxl, nxr
1729	DO j = nys, nyn
1730	topo(nzb_local(j,i)+1:nzt+1,j,i) = IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1731	ENDDO
1732	ENDDO
1733	DEALLOCATE( nzb_local )
1734
1735	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1736	!
1737	!-- Set boundary conditions also for flags. Can be interpreted as Neumann boundary conditions
1738	!-- for topography.
1739	IF ( .NOT. bc_ns_cyc ) THEN
1740	IF ( nys == 0 ) THEN
1741	DO i = 1, nbgp
1742	topo(:,nys-i,:) = topo(:,nys,:)
1743	ENDDO
1744	ENDIF
1745	IF ( nyn == ny ) THEN
1746	DO i = 1, nbgp
1747	topo(:,nyn+i,:) = topo(:,nyn,:)
1748	ENDDO
1749	ENDIF
1750	ENDIF
1751	IF ( .NOT. bc_lr_cyc ) THEN
1752	IF ( nxl == 0 ) THEN
1753	DO i = 1, nbgp
1754	topo(:,:,nxl-i) = topo(:,:,nxl)
1755	ENDDO
1756	ENDIF
1757	IF ( nxr == nx ) THEN
1758	DO i = 1, nbgp
1759	topo(:,:,nxr+i) = topo(:,:,nxr)
1760	ENDDO
1761	ENDIF
1762	ENDIF
1763
1764	CASE ( 'tunnel' )
1765
1766	!
1767	!-- Tunnel height
1768	IF ( tunnel_height == 9999999.9_wp ) THEN
1769	th = zw( INT( 0.2 * nz) )
1770	ELSE
1771	th = tunnel_height
1772	ENDIF
1773	!
1774	!-- Tunnel-wall depth
1775	IF ( tunnel_wall_depth == 9999999.9_wp ) THEN
1776	td = MAX ( dx, dy, dz(1) )
1777	ELSE
1778	td = tunnel_wall_depth
1779	ENDIF
1780	!
1781	!-- Check for tunnel width
1782	IF ( tunnel_width_x == 9999999.9_wp .AND. tunnel_width_y == 9999999.9_wp ) THEN
1783	message_string = 'No tunnel width is given. '
1784	CALL message( 'init_grid', 'PA0280', 1, 2, 0, 6, 0 )
1785	ENDIF
1786	IF ( tunnel_width_x /= 9999999.9_wp .AND. tunnel_width_y /= 9999999.9_wp ) THEN
1787	message_string = 'Inconsistent tunnel parameters:' // &
1788	'tunnel can only be oriented' // &
1789	'either in x- or in y-direction.'
1790	CALL message( 'init_grid', 'PA0281', 1, 2, 0, 6, 0 )
1791	ENDIF
1792	!
1793	!-- Check for too small tunnel width in x- and y-direction
1794	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
1795	tunnel_width_x - 2.0_wp * td <= 2.0_wp * dx ) THEN
1796	message_string = 'tunnel_width_x too small'
1797	CALL message( 'init_grid', 'PA0175', 1, 2, 0, 6, 0 )
1798	ENDIF
1799	IF ( tunnel_width_y /= 9999999.9_wp .AND. &
1800	tunnel_width_y - 2.0_wp * td <= 2.0_wp * dy ) THEN
1801	message_string = 'tunnel_width_y too small'
1802	CALL message( 'init_grid', 'PA0455', 1, 2, 0, 6, 0 )
1803	ENDIF
1804	!
1805	!-- Check for too large tunnel width.
1806	!-- Tunnel axis along y.
1807	IF ( tunnel_width_x /= 9999999.9_wp ) THEN
1808	IF ( tunnel_width_x > ( nx + 1 ) * dx ) THEN
1809	message_string = 'tunnel_width_x too large'
1810	CALL message( 'init_grid', 'PA0282', 1, 2, 0, 6, 0 )
1811	ENDIF
1812
1813	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_width_x * 0.5_wp )
1814	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_width_x * 0.5_wp )
1815	txs_in = INT( ( nx + 1 ) * 0.5_wp * dx - ( tunnel_width_x * 0.5_wp - td ) )
1816	txe_in = INT( ( nx + 1 ) * 0.5_wp * dx + ( tunnel_width_x * 0.5_wp - td ) )
1817
1818	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_length * 0.5_wp )
1819	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_length * 0.5_wp )
1820	tys_in = tys_out
1821	tye_in = tye_out
1822	ENDIF
1823	!
1824	!-- Tunnel axis along x.
1825	IF ( tunnel_width_y /= 9999999.9_wp ) THEN
1826	IF ( tunnel_width_y > ( ny + 1 ) * dy ) THEN
1827	message_string = 'tunnel_width_y too large'
1828	CALL message( 'init_grid', 'PA0456', 1, 2, 0, 6, 0 )
1829	ENDIF
1830
1831	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_length * 0.5_wp )
1832	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_length * 0.5_wp )
1833	txs_in = txs_out
1834	txe_in = txe_out
1835
1836	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_width_y * 0.5_wp )
1837	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_width_y * 0.5_wp )
1838	tys_in = INT( ( ny + 1 ) * 0.5_wp * dy - ( tunnel_width_y * 0.5_wp - td ) )
1839	tye_in = INT( ( ny + 1 ) * 0.5_wp * dy + ( tunnel_width_y * 0.5_wp - td ) )
1840	ENDIF
1841
1842	topo = 0
1843	DO i = nxl, nxr
1844	DO j = nys, nyn
1845	!
1846	!-- Use heaviside function to model outer tunnel surface
1847	hv_out = th * 0.5_wp * ( ( SIGN( 1.0_wp, i * dx - txs_out ) + 1.0_wp ) &
1848	- ( SIGN( 1.0_wp, i * dx - txe_out ) + 1.0_wp ) )
1849
1850	hv_out = hv_out * 0.5_wp * ( ( SIGN( 1.0_wp, j * dy - tys_out ) + 1.0_wp ) &
1851	- ( SIGN( 1.0_wp, j * dy - tye_out ) + 1.0_wp ) )
1852	!
1853	!-- Use heaviside function to model inner tunnel surface
1854	hv_in = ( th - td ) * 0.5_wp * ( ( SIGN( 1.0_wp, i * dx - txs_in ) + 1.0_wp ) &
1855	- ( SIGN( 1.0_wp, i * dx - txe_in ) + 1.0_wp ) )
1856
1857	hv_in = hv_in * 0.5_wp * ( ( SIGN( 1.0_wp, j * dy - tys_in ) + 1.0_wp ) &
1858	- ( SIGN( 1.0_wp, j * dy - tye_in ) + 1.0_wp ) )
1859	!
1860	!-- Set flags at x-y-positions without any tunnel surface
1861	IF ( hv_out - hv_in == 0.0_wp ) THEN
1862	topo(nzb+1:nzt+1,j,i) = IBSET( topo(nzb+1:nzt+1,j,i), 0 )
1863	!
1864	!-- Set flags at x-y-positions with tunnel surfaces
1865	ELSE
1866	DO k = nzb + 1, nzt + 1
1867	!
1868	!-- Inner tunnel
1869	IF ( hv_out - hv_in == th ) THEN
1870	IF ( zw(k) <= hv_out ) THEN
1871	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
1872	ELSE
1873	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
1874	ENDIF
1875	ENDIF
1876	!
1877	!-- Lateral tunnel walls
1878	IF ( hv_out - hv_in == td ) THEN
1879	IF ( zw(k) <= hv_in ) THEN
1880	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
1881	ELSEIF ( zw(k) > hv_in .AND. zw(k) <= hv_out ) THEN
1882	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
1883	ELSEIF ( zw(k) > hv_out ) THEN
1884	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
1885	ENDIF
1886	ENDIF
1887	ENDDO
1888	ENDIF
1889	ENDDO
1890	ENDDO
1891
1892	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1893	!
1894	!-- Set boundary conditions also for flags. Can be interpreted as Neumann boundary conditions
1895	!-- for topography.
1896	IF ( .NOT. bc_ns_cyc ) THEN
1897	IF ( nys == 0 ) THEN
1898	DO i = 1, nbgp
1899	topo(:,nys-i,:) = topo(:,nys,:)
1900	ENDDO
1901	ENDIF
1902	IF ( nyn == ny ) THEN
1903	DO i = 1, nbgp
1904	topo(:,nyn+i,:) = topo(:,nyn,:)
1905	ENDDO
1906	ENDIF
1907	ENDIF
1908	IF ( .NOT. bc_lr_cyc ) THEN
1909	IF ( nxl == 0 ) THEN
1910	DO i = 1, nbgp
1911	topo(:,:,nxl-i) = topo(:,:,nxl)
1912	ENDDO
1913	ENDIF
1914	IF ( nxr == nx ) THEN
1915	DO i = 1, nbgp
1916	topo(:,:,nxr+i) = topo(:,:,nxr)
1917	ENDDO
1918	ENDIF
1919	ENDIF
1920
1921	CASE ( 'read_from_file' )
1922	!
1923	!-- Note, topography information have been already read.
1924	!-- If required, further process topography, i.e. reference buildings on top of orography and
1925	!-- set temporary 3D topography array, which is used later to set grid flags. Calling of this
1926	!-- rouinte is also required in case of ASCII input, even though no distinction between
1927	!-- terrain- and building height is made in this case.
1928	CALL process_topography( topo )
1929	!
1930	!-- Filter holes resolved by only one grid-point
1931	CALL filter_topography( topo )
1932	!
1933	!-- Exchange ghost-points, as well as add cyclic or Neumann boundary conditions.
1934	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1935	!
1936	!-- Set lateral boundary conditions for topography on all ghost layers
1937	IF ( .NOT. bc_ns_cyc ) THEN
1938	IF ( nys == 0 ) THEN
1939	DO i = 1, nbgp
1940	topo(:,nys-i,:) = topo(:,nys,:)
1941	ENDDO
1942	ENDIF
1943	IF ( nyn == ny ) THEN
1944	DO i = 1, nbgp
1945	topo(:,nyn+i,:) = topo(:,nyn,:)
1946	ENDDO
1947	ENDIF
1948	ENDIF
1949
1950	IF ( .NOT. bc_lr_cyc ) THEN
1951	IF ( nxl == 0 ) THEN
1952	DO i = 1, nbgp
1953	topo(:,:,nxl-i) = topo(:,:,nxl)
1954	ENDDO
1955	ENDIF
1956	IF ( nxr == nx ) THEN
1957	DO i = 1, nbgp
1958	topo(:,:,nxr+i) = topo(:,:,nxr)
1959	ENDDO
1960	ENDIF
1961	ENDIF
1962
1963
1964	CASE DEFAULT
1965	!
1966	!-- The DEFAULT case is reached either if the parameter topography contains a wrong character
1967	!-- string or if the user has defined a special case in the user interface. There, the
1968	!-- subroutine user_init_grid checks which of these two conditions applies.
1969	CALL user_init_grid( topo )
1970	CALL filter_topography( topo )
1971
1972	END SELECT
1973	!
1974	!-- Consistency checks and index array initialization are only required for non-flat topography.
1975	IF ( TRIM( topography ) /= 'flat' ) THEN
1976	!
1977	!-- In case of non-flat topography, check whether the convention how to define the topography
1978	!-- grid has been set correctly, or whether the default is applicable. If this is not possible,
1979	!-- abort.
1980	IF ( TRIM( topography_grid_convention ) == ' ' ) THEN
1981	IF ( TRIM( topography ) /= 'closed_channel' .AND. &
1982	TRIM( topography ) /= 'single_building' .AND. &
1983	TRIM( topography ) /= 'single_street_canyon' .AND. &
1984	TRIM( topography ) /= 'tunnel' .AND. &
1985	TRIM( topography ) /= 'read_from_file') THEN
1986	!-- The default value is not applicable here, because it is only valid for the four
1987	!-- standard cases 'single_building', 'single_street_canyon', 'tunnel' and 'read_from_file'
1988	!-- defined in init_grid.
1989	WRITE( message_string, * ) 'The value for "topography_grid_convention" ', &
1990	'is not set. Its default value is & only valid for ', &
1991	'"topography" = ''single_building'', ''tunnel'' ', &
1992	'''single_street_canyon'', ''closed_channel'' & or ', &
1993	'''read_from_file''.', &
1994	'& Choose ''cell_edge'' or ''cell_center''.'
1995	CALL message( 'init_grid', 'PA0239', 1, 2, 0, 6, 0 )
1996	ELSE
1997	!-- The default value is applicable here.
1998	!-- Set convention according to topography.
1999	IF ( TRIM( topography ) == 'single_building' .OR. &
2000	TRIM( topography ) == 'single_street_canyon' ) THEN
2001	topography_grid_convention = 'cell_edge'
2002	ELSEIF ( TRIM( topography ) == 'read_from_file' .OR. &
2003	TRIM( topography ) == 'tunnel') THEN
2004	topography_grid_convention = 'cell_center'
2005	ENDIF
2006	ENDIF
2007	ELSEIF ( TRIM( topography_grid_convention ) /= 'cell_edge' .AND. &
2008	TRIM( topography_grid_convention ) /= 'cell_center' ) THEN
2009	WRITE( message_string, * ) 'The value for "topography_grid_convention" is ', &
2010	'not recognized.& Choose ''cell_edge'' or ''cell_center''.'
2011	CALL message( 'init_grid', 'PA0240', 1, 2, 0, 6, 0 )
2012	ENDIF
2013
2014
2015	IF ( topography_grid_convention == 'cell_edge' ) THEN
2016	!
2017	!-- The array nzb_local as defined using the 'cell_edge' convention
2018	!-- describes the actual total size of topography which is defined at the
2019	!-- cell edges where u=0 on the topography walls in x-direction and v=0
2020	!-- on the topography walls in y-direction. However, PALM uses individual
2021	!-- arrays nzb_u\|v\|w\|s_inner\|outer that are based on nzb_s_inner.
2022	!-- Therefore, the extent of topography in nzb_local is now reduced by
2023	!-- 1dx at the E topography walls and by 1dy at the N topography walls
2024	!-- to form the basis for nzb_s_inner.
2025	!-- Note, the reverse memory access (i-j instead of j-i) is absolutely
2026	!-- required at this point.
2027	DO j = nys+1, nyn+1
2028	DO i = nxl-1, nxr
2029	DO k = nzb, nzt+1
2030	IF ( BTEST( topo(k,j,i), 0 ) .OR. BTEST( topo(k,j,i+1), 0 ) ) &
2031	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2032	ENDDO
2033	ENDDO
2034	ENDDO
2035	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2036
2037	DO i = nxl, nxr+1
2038	DO j = nys-1, nyn
2039	DO k = nzb, nzt+1
2040	IF ( BTEST( topo(k,j,i), 0 ) .OR. BTEST( topo(k,j+1,i), 0 ) ) &
2041	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2042	ENDDO
2043	ENDDO
2044	ENDDO
2045	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2046
2047	ENDIF
2048	ENDIF
2049
2050
2051	END SUBROUTINE init_topo
2052
2053	SUBROUTINE set_topo_flags(topo)
2054
2055	USE control_parameters, &
2056	ONLY: bc_lr_cyc, bc_ns_cyc, constant_flux_layer, scalar_advec, topography, &
2057	use_surface_fluxes, use_top_fluxes
2058
2059	USE exchange_horiz_mod, &
2060	ONLY: exchange_horiz_int
2061
2062	USE indices, &
2063	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt, topo_top_ind, &
2064	wall_flags_static_0, wall_flags_total_0
2065
2066	USE kinds
2067
2068	IMPLICIT NONE
2069
2070	INTEGER(iwp) :: i !< index variable along x
2071	INTEGER(iwp) :: ibit !< integer bit position of topgraphy masking array
2072	INTEGER(iwp) :: j !< index variable along y
2073	INTEGER(iwp) :: k !< index variable along z
2074
2075	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting
2076	!< "outer"-flags
2077
2078	ALLOCATE( wall_flags_static_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2079	wall_flags_static_0 = 0
2080	!
2081	!-- Set-up topography flags. First, set flags only for s, u, v and w-grid.
2082	!-- Further special flags will be set in following loops.
2083	DO i = nxl, nxr
2084	DO j = nys, nyn
2085	DO k = nzb, nzt+1
2086	!
2087	!-- scalar grid
2088	IF ( BTEST( topo(k,j,i), 0 ) ) &
2089	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 0 )
2090	!
2091	!-- u grid
2092	IF ( BTEST( topo(k,j,i), 0 ) .AND. BTEST( topo(k,j,i-1), 0 ) ) &
2093	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 1 )
2094	!
2095	!-- v grid
2096	IF ( BTEST( topo(k,j,i), 0 ) .AND. BTEST( topo(k,j-1,i), 0 ) ) &
2097	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 2 )
2098
2099	ENDDO
2100
2101	DO k = nzb, nzt
2102	!
2103	!-- w grid
2104	IF ( BTEST( topo(k,j,i), 0 ) .AND. BTEST( topo(k+1,j,i), 0 ) ) &
2105	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 3 )
2106	ENDDO
2107
2108	IF ( topography /= 'closed_channel' ) THEN
2109	wall_flags_static_0(nzt+1,j,i) = IBSET( wall_flags_static_0(nzt+1,j,i), 3 )
2110	ENDIF
2111
2112	ENDDO
2113	ENDDO
2114
2115	CALL exchange_horiz_int( wall_flags_static_0, nys, nyn, nxl, nxr, nzt, nbgp )
2116
2117	!
2118	!-- Set outer array for scalars to mask near-surface grid points. Note, on basis of flag 24 futher
2119	!-- flags will be derived which are used to control production of subgrid TKE production near walls.
2120
2121	ALLOCATE( wall_flags_total_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2122	wall_flags_total_0 = 0
2123
2124	DO i = nxl, nxr
2125	DO j = nys, nyn
2126	DO k = nzb, nzt+1
2127	wall_flags_total_0(k,j,i) = IOR( wall_flags_total_0(k,j,i), wall_flags_static_0(k,j,i) )
2128	ENDDO
2129	ENDDO
2130	ENDDO
2131
2132	CALL exchange_horiz_int( wall_flags_total_0, nys, nyn, nxl, nxr, nzt, nbgp )
2133
2134	DO i = nxl, nxr
2135	DO j = nys, nyn
2136	DO k = nzb, nzt+1
2137	IF ( BTEST( wall_flags_total_0(k,j-1,i), 0 ) .AND. &
2138	BTEST( wall_flags_total_0(k,j+1,i), 0 ) .AND. &
2139	BTEST( wall_flags_total_0(k,j,i-1), 0 ) .AND. &
2140	BTEST( wall_flags_total_0(k,j,i+1), 0 ) .AND. &
2141	BTEST( wall_flags_total_0(k,j-1,i-1), 0 ) .AND. &
2142	BTEST( wall_flags_total_0(k,j+1,i-1), 0 ) .AND. &
2143	BTEST( wall_flags_total_0(k,j-1,i+1), 0 ) .AND. &
2144	BTEST( wall_flags_total_0(k,j+1,i+1), 0 ) ) &
2145	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 24 )
2146	ENDDO
2147	ENDDO
2148	ENDDO
2149	!
2150	!-- Set further special flags
2151	DO i = nxl, nxr
2152	DO j = nys, nyn
2153	DO k = nzb, nzt+1
2154	!
2155	!-- scalar grid, former nzb_diff_s_inner.
2156	!-- Note, use this flag also to mask topography in diffusion_u and diffusion_v along the
2157	!-- vertical direction. In case of use_surface_fluxes, fluxes are calculated via MOST,
2158	!-- else, simple gradient approach is applied. Please note, in case of u- and v-diffuison,
2159	!-- a small error is made at edges (on the east side for u, at the north side for v), since
2160	!-- topography on scalar grid point is used instead of topography on u/v-grid. As number of
2161	!-- topography grid points on uv-grid is different than s-grid, different number of surface
2162	!-- elements would be required. In order to avoid this, treat edges (u(k,j,i+1)) simply by
2163	!-- a gradient approach, i.e. these points are not masked within diffusion_u. Tests had
2164	!-- shown that the effect on the flow is negligible.
2165	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2166	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2167	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 8 )
2168	ELSE
2169	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 8 )
2170	ENDIF
2171
2172	ENDDO
2173	!
2174	!-- Special flag to control vertical diffusion at model top - former nzt_diff
2175	wall_flags_total_0(:,j,i) = IBSET( wall_flags_total_0(:,j,i), 9 )
2176	IF ( use_top_fluxes ) &
2177	wall_flags_total_0(nzt+1,j,i) = IBCLR( wall_flags_total_0(nzt+1,j,i), 9 )
2178
2179
2180	DO k = nzb+1, nzt
2181	!
2182	!-- Special flag on u grid, former nzb_u_inner + 1, required for disturb_field and
2183	!-- initialization. Do not disturb directly at topography, as well as initialize u with
2184	!-- zero one grid point outside of topography.
2185	IF ( BTEST( wall_flags_total_0(k-1,j,i), 1 ) .AND. &
2186	BTEST( wall_flags_total_0(k,j,i), 1 ) .AND. &
2187	BTEST( wall_flags_total_0(k+1,j,i), 1 ) ) &
2188	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 20 )
2189	!
2190	!-- Special flag on v grid, former nzb_v_inner + 1, required for disturb_field and
2191	!-- initialization. Do not disturb directly at topography, as well as initialize v with
2192	!-- zero one grid point outside of topography.
2193	IF ( BTEST( wall_flags_total_0(k-1,j,i), 2 ) .AND. &
2194	BTEST( wall_flags_total_0(k,j,i), 2 ) .AND. &
2195	BTEST( wall_flags_total_0(k+1,j,i), 2 ) ) &
2196	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 21 )
2197	!
2198	!-- Special flag on scalar grid, former nzb_s_inner+1. Used for lpm_sgs_tke
2199	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2200	BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2201	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2202	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 25 )
2203	!
2204	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in in production_e
2205	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2206	IF ( BTEST( wall_flags_total_0(k,j,i), 24 ) .AND. &
2207	BTEST( wall_flags_total_0(k-1,j,i), 24 ) .AND. &
2208	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2209	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 29 )
2210	ELSE
2211	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2212	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 29 )
2213	ENDIF
2214	!
2215	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2216	!-- in production_e
2217	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2218	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2219	BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2220	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2221	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 30 )
2222	ELSE
2223	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2224	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 30 )
2225	ENDIF
2226	ENDDO
2227	!
2228	!-- Flags indicating downward facing walls
2229	DO k = nzb+1, nzt+1
2230	!
2231	!-- Scalar grid
2232	IF ( BTEST( wall_flags_total_0(k-1,j,i), 0 ) .AND. &
2233	.NOT. BTEST( wall_flags_total_0(k,j,i), 0 ) ) &
2234	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 13 )
2235	!
2236	!-- Downward facing wall on u grid
2237	IF ( BTEST( wall_flags_total_0(k-1,j,i), 1 ) .AND. &
2238	.NOT. BTEST( wall_flags_total_0(k,j,i), 1 ) ) &
2239	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 15 )
2240	!
2241	!-- Downward facing wall on v grid
2242	IF ( BTEST( wall_flags_total_0(k-1,j,i), 2 ) .AND. &
2243	.NOT. BTEST( wall_flags_total_0(k,j,i), 2 ) ) &
2244	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 17 )
2245	!
2246	!-- Downward facing wall on w grid
2247	IF ( BTEST( wall_flags_total_0(k-1,j,i), 3 ) .AND. &
2248	.NOT. BTEST( wall_flags_total_0(k,j,i), 3 ) ) &
2249	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 19 )
2250	ENDDO
2251	!
2252	!-- Flags indicating upward facing walls
2253	DO k = nzb, nzt
2254	!
2255	!-- Upward facing wall on scalar grid
2256	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2257	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2258	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 12 )
2259	!
2260	!-- Upward facing wall on u grid
2261	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 1 ) .AND. &
2262	BTEST( wall_flags_total_0(k+1,j,i), 1 ) ) &
2263	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 14 )
2264
2265	!
2266	!-- Upward facing wall on v grid
2267	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 2 ) .AND. &
2268	BTEST( wall_flags_total_0(k+1,j,i), 2 ) ) &
2269	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 16 )
2270
2271	!
2272	!-- Upward facing wall on w grid
2273	IF ( .NOT. BTEST( wall_flags_total_0(k,j,i), 3 ) .AND. &
2274	BTEST( wall_flags_total_0(k+1,j,i), 3 ) ) &
2275	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 18 )
2276	!
2277	!-- Special flag on scalar grid, former nzb_s_inner
2278	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .OR. &
2279	BTEST( wall_flags_total_0(k,j,i), 12 ) .OR. &
2280	BTEST( wall_flags_total_0(k,j,i), 13 ) ) &
2281	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 22 )
2282	!
2283	!-- Special flag on scalar grid, nzb_diff_s_inner - 1, required for
2284	!-- flow_statistics
2285	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2286	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. &
2287	BTEST( wall_flags_total_0(k+1,j,i), 0 ) ) &
2288	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 23 )
2289	ELSE
2290	IF ( BTEST( wall_flags_total_0(k,j,i), 22 ) ) &
2291	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 23 )
2292	ENDIF
2293
2294
2295	ENDDO
2296	wall_flags_total_0(nzt+1,j,i) = IBSET( wall_flags_total_0(nzt+1,j,i), 22 )
2297	wall_flags_total_0(nzt+1,j,i) = IBSET( wall_flags_total_0(nzt+1,j,i), 23 )
2298	!
2299	!-- Set flags indicating that topography is close by in horizontal direction, i.e. flags that
2300	!-- infold the topography. These will be used to set advection flags for passive scalars,
2301	!-- where due to large gradients near buildings stationary numerical oscillations can produce
2302	!-- unrealistically high concentrations. This is only necessary if WS-scheme is applied for
2303	!-- scalar advection. Note, these flags will be only used for passive scalars such as chemical
2304	!-- species or aerosols.
2305	IF ( scalar_advec == 'ws-scheme' ) THEN
2306	DO k = nzb, nzt
2307	IF ( BTEST( wall_flags_total_0(k,j,i), 0 ) .AND. ( &
2308	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-1), 0 ) ) .OR. &
2309	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-2), 0 ) ) .OR. &
2310	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i-3), 0 ) ) .OR. &
2311	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+1), 0 ) ) .OR. &
2312	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+2), 0 ) ) .OR. &
2313	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3:j+3,i+3), 0 ) ) .OR. &
2314	ANY( .NOT. BTEST( wall_flags_total_0(k,j-1,i-3:i+3), 0 ) ) .OR. &
2315	ANY( .NOT. BTEST( wall_flags_total_0(k,j-2,i-3:i+3), 0 ) ) .OR. &
2316	ANY( .NOT. BTEST( wall_flags_total_0(k,j-3,i-3:i+3), 0 ) ) .OR. &
2317	ANY( .NOT. BTEST( wall_flags_total_0(k,j+1,i-3:i+3), 0 ) ) .OR. &
2318	ANY( .NOT. BTEST( wall_flags_total_0(k,j+2,i-3:i+3), 0 ) ) .OR. &
2319	ANY( .NOT. BTEST( wall_flags_total_0(k,j+3,i-3:i+3), 0 ) ) &
2320	) &
2321	) &
2322	wall_flags_total_0(k,j,i) = IBSET( wall_flags_total_0(k,j,i), 31 )
2323	ENDDO
2324	ENDIF
2325	ENDDO
2326	ENDDO
2327	!
2328	!-- Finally, set identification flags indicating natural terrain or buildings.
2329	!-- Natural terrain grid points. Information on the type of the surface is stored in bit 1 of
2330	!-- 3D Integer array topo. However, this bit is only set when topography is read from file. In order
2331	!-- to run the land-surface model also without topography information, set bit 1 explicitely in this
2332	!-- case.
2333	!--
2334	!-- Natural terrain grid points
2335	!-- If no topography is initialized, the land-surface is at k = nzb.
2336	IF ( TRIM( topography ) /= 'read_from_file' ) THEN
2337	wall_flags_static_0(nzb,:,:) = IBSET( wall_flags_static_0(nzb,:,:), 5 )
2338	ELSE
2339	DO i = nxl, nxr
2340	DO j = nys, nyn
2341	DO k = nzb, nzt+1
2342	!
2343	!-- Natural terrain grid point
2344	IF ( BTEST( topo(k,j,i), 1 ) ) &
2345	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 5 )
2346	ENDDO
2347	ENDDO
2348	ENDDO
2349	ENDIF
2350	!
2351	!-- Building grid points.
2352	DO i = nxl, nxr
2353	DO j = nys, nyn
2354	DO k = nzb, nzt+1
2355	IF ( BTEST( topo(k,j,i), 2 ) ) &
2356	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 6 )
2357	ENDDO
2358	ENDDO
2359	ENDDO
2360	!
2361	!-- Set flag 4, indicating new topography grid points due to filtering.
2362	DO i = nxl, nxr
2363	DO j = nys, nyn
2364	DO k = nzb, nzt+1
2365	IF ( BTEST( topo(k,j,i), 4 ) ) &
2366	wall_flags_static_0(k,j,i) = IBSET( wall_flags_static_0(k,j,i), 4 )
2367	ENDDO
2368	ENDDO
2369	ENDDO
2370
2371	CALL exchange_horiz_int( wall_flags_static_0, nys, nyn, nxl, nxr, nzt, nbgp )
2372
2373	DO i = nxl, nxr
2374	DO j = nys, nyn
2375	DO k = nzb, nzt+1
2376	wall_flags_total_0(k,j,i) = IOR( wall_flags_total_0(k,j,i), wall_flags_static_0(k,j,i) )
2377	ENDDO
2378	ENDDO
2379	ENDDO
2380	!
2381	!-- Exchange ghost points for wall flags
2382	CALL exchange_horiz_int( wall_flags_total_0, nys, nyn, nxl, nxr, nzt, nbgp )
2383	!
2384	!-- Set boundary conditions also for flags. Can be interpreted as Neumann boundary conditions for
2385	!-- topography.
2386	IF ( .NOT. bc_ns_cyc ) THEN
2387	IF ( nys == 0 ) THEN
2388	DO i = 1, nbgp
2389	wall_flags_total_0(:,nys-i,:) = wall_flags_total_0(:,nys,:)
2390	ENDDO
2391	ENDIF
2392	IF ( nyn == ny ) THEN
2393	DO i = 1, nbgp
2394	wall_flags_total_0(:,nyn+i,:) = wall_flags_total_0(:,nyn,:)
2395	ENDDO
2396	ENDIF
2397	ENDIF
2398	IF ( .NOT. bc_lr_cyc ) THEN
2399	IF ( nxl == 0 ) THEN
2400	DO i = 1, nbgp
2401	wall_flags_total_0(:,:,nxl-i) = wall_flags_total_0(:,:,nxl)
2402	ENDDO
2403	ENDIF
2404	IF ( nxr == nx ) THEN
2405	DO i = 1, nbgp
2406	wall_flags_total_0(:,:,nxr+i) = wall_flags_total_0(:,:,nxr)
2407	ENDDO
2408	ENDIF
2409	ENDIF
2410	!
2411	!-- Pre-calculate topography top indices (former get_topography_top_index
2412	!-- function)
2413	ALLOCATE( topo_top_ind(nysg:nyng,nxlg:nxrg,0:4) )
2414	!
2415	!-- Uppermost topography index on scalar grid
2416	ibit = 12
2417	topo_top_ind(:,:,0) = MAXLOC( MERGE( 1, 0, BTEST( wall_flags_total_0(:,:,:), ibit ) ), DIM=1 ) &
2418	- 1
2419	!
2420	!-- Uppermost topography index on u grid
2421	ibit = 14
2422	topo_top_ind(:,:,1) = MAXLOC( MERGE( 1, 0, BTEST( wall_flags_total_0(:,:,:), ibit ) ), DIM=1 ) &
2423	- 1
2424	!
2425	!-- Uppermost topography index on v grid
2426	ibit = 16
2427	topo_top_ind(:,:,2) = MAXLOC( MERGE( 1, 0, BTEST( wall_flags_total_0(:,:,:), ibit ) ), DIM=1 ) &
2428	- 1
2429	!
2430	!-- Uppermost topography index on w grid
2431	ibit = 18
2432	topo_top_ind(:,:,3) = MAXLOC( MERGE( 1, 0, BTEST( wall_flags_total_0(:,:,:), ibit ) ), DIM=1 ) &
2433	- 1
2434	!
2435	!-- Uppermost topography index on scalar outer grid
2436	ibit = 24
2437	topo_top_ind(:,:,4) = MAXLOC( MERGE( 1, 0, BTEST( wall_flags_total_0(:,:,:), ibit ) ), DIM=1 ) &
2438	- 1
2439
2440	END SUBROUTINE set_topo_flags

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