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source: palm/trunk/SOURCE/init_grid.f90 @ 4304

Last change on this file since 4304 was 4294, checked in by suehring, 5 years ago
init_grid: always set bit 5 and 6 of wall_flags, indicating terrain- and building surfaces in all cases, in order to enable terrain-following output also when no land- or urban-surface model is applied
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1	!> @file init_grid.f90
2	!------------------------------------------------------------------------------!
3	! This file is part of the PALM model system.
4	!
5	! PALM is free software: you can redistribute it and/or modify it under the
6	! terms of the GNU General Public License as published by the Free Software
7	! Foundation, either version 3 of the License, or (at your option) any later
8	! version.
9	!
10	! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
11	! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
12	! A PARTICULAR PURPOSE. See the GNU General Public License for more details.
13	!
14	! You should have received a copy of the GNU General Public License along with
15	! PALM. If not, see <http://www.gnu.org/licenses/>.
16	!
17	! Copyright 1997-2019 Leibniz Universitaet Hannover
18	!------------------------------------------------------------------------------!
19	!
20	! Current revisions:
21	! -----------------
22	!
23	!
24	! Former revisions:
25	! -----------------
26	! $Id: init_grid.f90 4294 2019-11-13 18:34:16Z banzhafs $
27	! Bugfix, always set bit 5 and 6 of wall_flags, indicating terrain- and
28	! building surfaces in all cases, in order to enable terrain-following output
29	! also when no land- or urban-surface model is applied.
30	!
31	! 4265 2019-10-15 16:16:24Z suehring
32	! Bugfix for last commit, exchange oro_max variable only when it is allocated
33	! (not necessarily the case when topography is input from ASCII file).
34	!
35	! 4245 2019-09-30 08:40:37Z pavelkrc
36	! Store oro_max (building z-offset) in 2D for building surfaces
37	!
38	! 4189 2019-08-26 16:19:38Z suehring
39	! - Add check for proper setting of namelist parameter topography
40	! - Set flag to indicate land surfaces in case no topography is provided
41	!
42	! 4182 2019-08-22 15:20:23Z scharf
43	! Corrected "Former revisions" section
44	!
45	! 4168 2019-08-16 13:50:17Z suehring
46	! Pre-calculate topography top index and store it on an array (replaces former
47	! functions get_topography_top_index)
48	!
49	! 4159 2019-08-15 13:31:35Z suehring
50	! Revision of topography processing. This was not consistent between 2D and 3D
51	! buildings.
52	!
53	! 4144 2019-08-06 09:11:47Z raasch
54	! relational operators .EQ., .NE., etc. replaced by ==, /=, etc.
55	!
56	! 4115 2019-07-24 12:50:49Z suehring
57	! Bugfix in setting near-surface flag 24, inidicating wall-bounded grid points
58	!
59	! 4110 2019-07-22 17:05:21Z suehring
60	! - Separate initialization of advection flags for momentum and scalars.
61	! - Change subroutine interface for ws_init_flags_scalar to pass boundary flags
62	!
63	! 4109 2019-07-22 17:00:34Z suehring
64	! Fix bad commit
65	!
66	! 3926 2019-04-23 12:56:42Z suehring
67	! Minor bugfix in building mapping when all building IDs in the model domain
68	! are missing
69	!
70	! 3857 2019-04-03 13:00:16Z knoop
71	! In projection of non-building 3D objects onto numerical grid remove
72	! dependency on building_type
73	!
74	! 3763 2019-02-25 17:33:49Z suehring
75	! Replace work-around for ghost point exchange of 1-byte arrays with specific
76	! routine as already done in other routines
77	!
78	! 3761 2019-02-25 15:31:42Z raasch
79	! unused variables removed
80	!
81	! 3661 2019-01-08 18:22:50Z suehring
82	! Remove setting of nzb_max to nzt at non-cyclic boundary PEs, instead,
83	! order degradation of advection scheme is handeled directly in advec_ws
84	!
85	! 3655 2019-01-07 16:51:22Z knoop
86	! Comment added
87	!
88	! Revision 1.1 1997/08/11 06:17:45 raasch
89	! Initial revision (Testversion)
90	!
91	!
92	! Description:
93	! -----------------------------------------------------------------------------!
94	!> Creating grid depending constants
95	!> @todo: Rearrange topo flag list
96	!> @todo: reference 3D buildings on top of orography is not tested and may need
97	!> further improvement for steep slopes
98	!> @todo: Use more advanced setting of building type at filled holes
99	!------------------------------------------------------------------------------!
100	SUBROUTINE init_grid
101
102	USE advec_ws, &
103	ONLY: ws_init_flags_momentum, ws_init_flags_scalar
104
105	USE arrays_3d, &
106	ONLY: dd2zu, ddzu, ddzu_pres, ddzw, dzu, dzw, x, xu, y, yv, zu, zw
107
108	USE control_parameters, &
109	ONLY: bc_lr_cyc, bc_ns_cyc, &
110	bc_dirichlet_l, &
111	bc_dirichlet_n, &
112	bc_dirichlet_r, &
113	bc_dirichlet_s, &
114	bc_radiation_l, &
115	bc_radiation_n, &
116	bc_radiation_r, &
117	bc_radiation_s, &
118	constant_flux_layer, dz, dz_max, dz_stretch_factor, &
119	dz_stretch_factor_array, dz_stretch_level, dz_stretch_level_end,&
120	dz_stretch_level_end_index, dz_stretch_level_start_index, &
121	dz_stretch_level_start, ibc_uv_b, message_string, &
122	momentum_advec, number_stretch_level_end, &
123	number_stretch_level_start, ocean_mode, psolver, scalar_advec, &
124	topography, use_surface_fluxes
125
126	USE grid_variables, &
127	ONLY: ddx, ddx2, ddy, ddy2, dx, dx2, dy, dy2, zu_s_inner, zw_w_inner
128
129	USE indices, &
130	ONLY: advc_flags_m, &
131	advc_flags_s, &
132	nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
133	nzb, nzb_diff, nzb_diff_s_inner, nzb_diff_s_outer, &
134	nzb_max, nzb_s_inner, nzb_s_outer, nzb_u_inner, &
135	nzb_u_outer, nzb_v_inner, nzb_v_outer, nzb_w_inner, &
136	nzb_w_outer, nzt, topo_top_ind, topo_min_level
137
138	USE kinds
139
140	USE pegrid
141
142	USE poismg_noopt_mod
143
144	USE surface_mod, &
145	ONLY: init_bc
146
147	USE vertical_nesting_mod, &
148	ONLY: vnested, vnest_init_grid
149
150	IMPLICIT NONE
151
152	INTEGER(iwp) :: i !< index variable along x
153	INTEGER(iwp) :: j !< index variable along y
154	INTEGER(iwp) :: k !< index variable along z
155	INTEGER(iwp) :: k_top !< topography top index on local PE
156	INTEGER(iwp) :: n !< loop variable for stretching
157	INTEGER(iwp) :: number_dz !< number of user-specified dz values
158	INTEGER(iwp) :: nzb_local_max !< vertical grid index of maximum topography height
159	INTEGER(iwp) :: nzb_local_min !< vertical grid index of minimum topography height
160
161	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
162	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_tmp !< dummy to calculate topography indices on u- and v-grid
163
164	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
165
166	REAL(wp) :: dz_level_end !< distance between calculated height level for u/v-grid and user-specified end level for stretching
167	REAL(wp) :: dz_stretched !< stretched vertical grid spacing
168
169	REAL(wp), DIMENSION(:), ALLOCATABLE :: min_dz_stretch_level_end !< Array that contains all minimum heights where the stretching can end
170
171
172	!
173	!-- Calculation of horizontal array bounds including ghost layers
174	nxlg = nxl - nbgp
175	nxrg = nxr + nbgp
176	nysg = nys - nbgp
177	nyng = nyn + nbgp
178
179	!
180	!-- Allocate grid arrays
181	ALLOCATE( x(0:nx), xu(0:nx) )
182	DO i = 0, nx
183	xu(i) = i * dx
184	x(i) = i * dx + 0.5_wp * dx
185	ENDDO
186
187	ALLOCATE( y(0:ny), yv(0:ny) )
188	DO j = 0, ny
189	yv(j) = j * dy
190	y(j) = j * dy + 0.5_wp * dy
191	ENDDO
192
193	!
194	!-- Allocate grid arrays
195	ALLOCATE( ddzu(1:nzt+1), ddzw(1:nzt+1), dd2zu(1:nzt), dzu(1:nzt+1), &
196	dzw(1:nzt+1), zu(nzb:nzt+1), zw(nzb:nzt+1) )
197
198	!
199	!-- Compute height of u-levels from constant grid length and dz stretch factors
200	IF ( dz(1) == -1.0_wp ) THEN
201	message_string = 'missing dz'
202	CALL message( 'init_grid', 'PA0200', 1, 2, 0, 6, 0 )
203	ELSEIF ( dz(1) <= 0.0_wp ) THEN
204	WRITE( message_string, * ) 'dz=',dz(1),' <= 0.0'
205	CALL message( 'init_grid', 'PA0201', 1, 2, 0, 6, 0 )
206	ENDIF
207
208	!
209	!-- Initialize dz_stretch_level_start with the value of dz_stretch_level
210	!-- if it was set by the user
211	IF ( dz_stretch_level /= -9999999.9_wp ) THEN
212	dz_stretch_level_start(1) = dz_stretch_level
213	ENDIF
214
215	!
216	!-- Determine number of dz values and stretching levels specified by the
217	!-- user to allow right controlling of the stretching mechanism and to
218	!-- perform error checks. The additional requirement that dz /= dz_max
219	!-- for counting number of user-specified dz values is necessary. Otherwise
220	!-- restarts would abort if the old stretching mechanism with dz_stretch_level
221	!-- is used (Attention: The user is not allowed to specify a dz value equal
222	!-- to the default of dz_max = 999.0).
223	number_dz = COUNT( dz /= -1.0_wp .AND. dz /= dz_max)
224	number_stretch_level_start = COUNT( dz_stretch_level_start /= &
225	-9999999.9_wp )
226	number_stretch_level_end = COUNT( dz_stretch_level_end /= &
227	9999999.9_wp )
228
229	!
230	!-- The number of specified end levels +1 has to be the same than the number
231	!-- of specified dz values
232	IF ( number_dz /= number_stretch_level_end + 1 ) THEN
233	WRITE( message_string, * ) 'The number of values for dz = ', &
234	number_dz, 'has to be the same than& ', &
235	'the number of values for ', &
236	'dz_stretch_level_end + 1 = ', &
237	number_stretch_level_end+1
238	CALL message( 'init_grid', 'PA0156', 1, 2, 0, 6, 0 )
239	ENDIF
240
241	!
242	!-- The number of specified start levels has to be the same or one less than
243	!-- the number of specified dz values
244	IF ( number_dz /= number_stretch_level_start + 1 .AND. &
245	number_dz /= number_stretch_level_start ) THEN
246	WRITE( message_string, * ) 'The number of values for dz = ', &
247	number_dz, 'has to be the same or one ', &
248	'more than& the number of values for ', &
249	'dz_stretch_level_start = ', &
250	number_stretch_level_start
251	CALL message( 'init_grid', 'PA0211', 1, 2, 0, 6, 0 )
252	ENDIF
253
254	!-- The number of specified start levels has to be the same or one more than
255	!-- the number of specified end levels
256	IF ( number_stretch_level_start /= number_stretch_level_end + 1 .AND. &
257	number_stretch_level_start /= number_stretch_level_end ) THEN
258	WRITE( message_string, * ) 'The number of values for ', &
259	'dz_stretch_level_start = ', &
260	dz_stretch_level_start, 'has to be the ',&
261	'same or one more than& the number of ', &
262	'values for dz_stretch_level_end = ', &
263	number_stretch_level_end
264	CALL message( 'init_grid', 'PA0216', 1, 2, 0, 6, 0 )
265	ENDIF
266
267	!
268	!-- Initialize dz for the free atmosphere with the value of dz_max
269	IF ( dz(number_stretch_level_start+1) == -1.0_wp .AND. &
270	number_stretch_level_start /= 0 ) THEN
271	dz(number_stretch_level_start+1) = dz_max
272	ENDIF
273
274	!
275	!-- Initialize the stretching factor if (infinitely) stretching in the free
276	!-- atmosphere is desired (dz_stretch_level_end was not specified for the
277	!-- free atmosphere)
278	IF ( number_stretch_level_start == number_stretch_level_end + 1 ) THEN
279	dz_stretch_factor_array(number_stretch_level_start) = &
280	dz_stretch_factor
281	ENDIF
282
283	!
284	!-- Allocation of arrays for stretching
285	ALLOCATE( min_dz_stretch_level_end(number_stretch_level_start) )
286
287	!
288	!-- Define the vertical grid levels
289	IF ( .NOT. ocean_mode ) THEN
290
291	!
292	!-- The stretching region has to be large enough to allow for a smooth
293	!-- transition between two different grid spacings
294	DO n = 1, number_stretch_level_start
295	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) + &
296	4 * MAX( dz(n),dz(n+1) )
297	ENDDO
298
299	IF ( ANY( min_dz_stretch_level_end(1:number_stretch_level_start) > &
300	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
301	message_string= 'Eeach dz_stretch_level_end has to be larger ' // &
302	'than its corresponding value for &' // &
303	'dz_stretch_level_start + 4*MAX(dz(n),dz(n+1)) '//&
304	'to allow for smooth grid stretching'
305	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
306	ENDIF
307
308	!
309	!-- Stretching must not be applied within the prandtl_layer
310	!-- (first two grid points). For the default case dz_stretch_level_start
311	!-- is negative. Therefore the absolut value is checked here.
312	IF ( ANY( ABS( dz_stretch_level_start ) < dz(1) * 1.5_wp ) ) THEN
313	WRITE( message_string, * ) 'Eeach dz_stretch_level_start has to be ',&
314	'larger than ', dz(1) * 1.5
315	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
316	ENDIF
317
318	!
319	!-- The stretching has to start and end on a grid level. Therefore
320	!-- user-specified values have to ''interpolate'' to the next lowest level
321	IF ( number_stretch_level_start /= 0 ) THEN
322	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) - &
323	dz(1)/2.0) / dz(1) ) &
324	* dz(1) + dz(1)/2.0
325	ENDIF
326
327	IF ( number_stretch_level_start > 1 ) THEN
328	DO n = 2, number_stretch_level_start
329	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
330	dz(n) ) * dz(n)
331	ENDDO
332	ENDIF
333
334	IF ( number_stretch_level_end /= 0 ) THEN
335	DO n = 1, number_stretch_level_end
336	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
337	dz(n+1) ) * dz(n+1)
338	ENDDO
339	ENDIF
340
341	!
342	!-- Determine stretching factor if necessary
343	IF ( number_stretch_level_end >= 1 ) THEN
344	CALL calculate_stretching_factor( number_stretch_level_end )
345	ENDIF
346
347	!
348	!-- Grid for atmosphere with surface at z=0 (k=0, w-grid).
349	!-- First compute the u- and v-levels. In case of dirichlet bc for u and v
350	!-- the first u/v- and w-level (k=0) are defined at same height (z=0).
351	!-- The second u-level (k=1) corresponds to the top of the
352	!-- Prandtl-layer.
353	IF ( ibc_uv_b == 0 .OR. ibc_uv_b == 2 ) THEN
354	zu(0) = 0.0_wp
355	ELSE
356	zu(0) = - dz(1) * 0.5_wp
357	ENDIF
358
359	zu(1) = dz(1) * 0.5_wp
360
361	!
362	!-- Determine u and v height levels considering the possibility of grid
363	!-- stretching in several heights.
364	n = 1
365	dz_stretch_level_start_index = nzt+1
366	dz_stretch_level_end_index = nzt+1
367	dz_stretched = dz(1)
368
369	!-- The default value of dz_stretch_level_start is negative, thus the first
370	!-- condition is always true. Hence, the second condition is necessary.
371	DO k = 2, nzt+1
372	IF ( dz_stretch_level_start(n) <= zu(k-1) .AND. &
373	dz_stretch_level_start(n) /= -9999999.9_wp ) THEN
374	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
375
376	IF ( dz(n) > dz(n+1) ) THEN
377	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
378	ELSE
379	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
380	ENDIF
381
382	IF ( dz_stretch_level_start_index(n) == nzt+1 ) &
383	dz_stretch_level_start_index(n) = k-1
384
385	ENDIF
386
387	zu(k) = zu(k-1) + dz_stretched
388
389	!
390	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
391	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
392
393	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
394	zu(k) = dz_stretch_level_end(n)
395	dz_stretched = dz(n+1)
396	dz_stretch_level_end_index(n) = k
397	n = n + 1
398	ENDIF
399	ENDDO
400
401	!
402	!-- Compute the w-levels. They are always staggered half-way between the
403	!-- corresponding u-levels. In case of dirichlet bc for u and v at the
404	!-- ground the first u- and w-level (k=0) are defined at same height (z=0).
405	!-- The top w-level is extrapolated linearly.
406	zw(0) = 0.0_wp
407	DO k = 1, nzt
408	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
409	ENDDO
410	zw(nzt+1) = zw(nzt) + 2.0_wp * ( zu(nzt+1) - zw(nzt) )
411
412	ELSE
413
414	!
415	!-- The stretching region has to be large enough to allow for a smooth
416	!-- transition between two different grid spacings
417	DO n = 1, number_stretch_level_start
418	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) - &
419	4 * MAX( dz(n),dz(n+1) )
420	ENDDO
421
422	IF ( ANY( min_dz_stretch_level_end (1:number_stretch_level_start) < &
423	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
424	message_string= 'Eeach dz_stretch_level_end has to be less ' // &
425	'than its corresponding value for &' // &
426	'dz_stretch_level_start - 4*MAX(dz(n),dz(n+1)) '//&
427	'to allow for smooth grid stretching'
428	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
429	ENDIF
430
431	!
432	!-- Stretching must not be applied close to the surface (last two grid
433	!-- points). For the default case dz_stretch_level_start is negative.
434	IF ( ANY( dz_stretch_level_start > - dz(1) * 1.5_wp ) ) THEN
435	WRITE( message_string, * ) 'Eeach dz_stretch_level_start has to be ',&
436	'less than ', dz(1) * 1.5
437	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
438	ENDIF
439
440	!
441	!-- The stretching has to start and end on a grid level. Therefore
442	!-- user-specified values have to ''interpolate'' to the next highest level
443	IF ( number_stretch_level_start /= 0 ) THEN
444	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) + &
445	dz(1)/2.0) / dz(1) ) &
446	* dz(1) - dz(1)/2.0
447	ENDIF
448
449	IF ( number_stretch_level_start > 1 ) THEN
450	DO n = 2, number_stretch_level_start
451	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
452	dz(n) ) * dz(n)
453	ENDDO
454	ENDIF
455
456	IF ( number_stretch_level_end /= 0 ) THEN
457	DO n = 1, number_stretch_level_end
458	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
459	dz(n+1) ) * dz(n+1)
460	ENDDO
461	ENDIF
462
463	!
464	!-- Determine stretching factor if necessary
465	IF ( number_stretch_level_end >= 1 ) THEN
466	CALL calculate_stretching_factor( number_stretch_level_end )
467	ENDIF
468
469	!
470	!-- Grid for ocean with free water surface is at k=nzt (w-grid).
471	!-- In case of neumann bc at the ground the first first u-level (k=0) lies
472	!-- below the first w-level (k=0). In case of dirichlet bc the first u- and
473	!-- w-level are defined at same height, but staggered from the second level.
474	!-- The second u-level (k=1) corresponds to the top of the Prandtl-layer.
475	!-- z values are negative starting from z=0 (surface)
476	zu(nzt+1) = dz(1) * 0.5_wp
477	zu(nzt) = - dz(1) * 0.5_wp
478
479	!
480	!-- Determine u and v height levels considering the possibility of grid
481	!-- stretching in several heights.
482	n = 1
483	dz_stretch_level_start_index = 0
484	dz_stretch_level_end_index = 0
485	dz_stretched = dz(1)
486
487	DO k = nzt-1, 0, -1
488
489	IF ( dz_stretch_level_start(n) >= zu(k+1) ) THEN
490	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
491
492	IF ( dz(n) > dz(n+1) ) THEN
493	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
494	ELSE
495	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
496	ENDIF
497
498	IF ( dz_stretch_level_start_index(n) == 0 ) &
499	dz_stretch_level_start_index(n) = k+1
500
501	ENDIF
502
503	zu(k) = zu(k+1) - dz_stretched
504
505	!
506	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
507	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
508
509	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
510	zu(k) = dz_stretch_level_end(n)
511	dz_stretched = dz(n+1)
512	dz_stretch_level_end_index(n) = k
513	n = n + 1
514	ENDIF
515	ENDDO
516
517	!
518	!-- Compute the w-levels. They are always staggered half-way between the
519	!-- corresponding u-levels, except in case of dirichlet bc for u and v
520	!-- at the ground. In this case the first u- and w-level are defined at
521	!-- same height. The top w-level (nzt+1) is not used but set for
522	!-- consistency, since w and all scalar variables are defined up tp nzt+1.
523	zw(nzt+1) = dz(1)
524	zw(nzt) = 0.0_wp
525	DO k = 0, nzt
526	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
527	ENDDO
528
529	!
530	!-- In case of dirichlet bc for u and v the first u- and w-level are defined
531	!-- at same height.
532	IF ( ibc_uv_b == 0 ) THEN
533	zu(0) = zw(0)
534	ENDIF
535
536	ENDIF
537
538	!
539	!-- Compute grid lengths.
540	DO k = 1, nzt+1
541	dzu(k) = zu(k) - zu(k-1)
542	ddzu(k) = 1.0_wp / dzu(k)
543	dzw(k) = zw(k) - zw(k-1)
544	ddzw(k) = 1.0_wp / dzw(k)
545	ENDDO
546
547	DO k = 1, nzt
548	dd2zu(k) = 1.0_wp / ( dzu(k) + dzu(k+1) )
549	ENDDO
550
551	!
552	!-- The FFT- SOR-pressure solvers assume grid spacings of a staggered grid
553	!-- everywhere. For the actual grid, the grid spacing at the lowest level
554	!-- is only dz/2, but should be dz. Therefore, an additional array
555	!-- containing with appropriate grid information is created for these
556	!-- solvers.
557	IF ( psolver(1:9) /= 'multigrid' ) THEN
558	ALLOCATE( ddzu_pres(1:nzt+1) )
559	ddzu_pres = ddzu
560	ddzu_pres(1) = ddzu_pres(2) ! change for lowest level
561	ENDIF
562
563	!
564	!-- Compute the reciprocal values of the horizontal grid lengths.
565	ddx = 1.0_wp / dx
566	ddy = 1.0_wp / dy
567	dx2 = dx * dx
568	dy2 = dy * dy
569	ddx2 = 1.0_wp / dx2
570	ddy2 = 1.0_wp / dy2
571
572	!
573	!-- Allocate 3D array to set topography
574	ALLOCATE( topo(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
575	topo = 0
576	!
577	!-- Initialize topography by generic topography or read from topography from file.
578	CALL init_topo( topo )
579	!
580	!-- Set flags to mask topography on the grid.
581	CALL set_topo_flags( topo )
582	!
583	!-- Calculate wall flag arrays for the multigrid method.
584	!-- Please note, wall flags are only applied in the non-optimized version.
585	IF ( psolver == 'multigrid_noopt' ) CALL poismg_noopt_init
586
587	!
588	!-- Init flags for ws-scheme to degrade order of the numerics near walls, i.e.
589	!-- to decrease the numerical stencil appropriately. The order of the scheme
590	!-- is degraded near solid walls as well as near non-cyclic inflow and outflow
591	!-- boundaries. Do this separately for momentum and scalars.
592	IF ( momentum_advec == 'ws-scheme' ) THEN
593	ALLOCATE( advc_flags_m(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
594	CALL ws_init_flags_momentum
595	ENDIF
596	IF ( scalar_advec == 'ws-scheme' ) THEN
597	ALLOCATE( advc_flags_s(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
598	advc_flags_s = 0
599
600	CALL ws_init_flags_scalar( bc_dirichlet_l .OR. bc_radiation_l, &
601	bc_dirichlet_n .OR. bc_radiation_n, &
602	bc_dirichlet_r .OR. bc_radiation_r, &
603	bc_dirichlet_s .OR. bc_radiation_s, &
604	advc_flags_s )
605	ENDIF
606
607	!
608	!-- Determine the maximum level of topography. It is used for
609	!-- steering the degradation of order of the applied advection scheme,
610	!-- as well in the lpm.
611	k_top = 0
612	DO i = nxl, nxr
613	DO j = nys, nyn
614	DO k = nzb, nzt + 1
615	k_top = MAX( k_top, MERGE( k, 0, .NOT. BTEST( topo(k,j,i), 0 ) ) )
616	ENDDO
617	ENDDO
618	ENDDO
619	#if defined( __parallel )
620	CALL MPI_ALLREDUCE( k_top + 1, nzb_max, 1, MPI_INTEGER, & !is +1 really necessary here?
621	MPI_MAX, comm2d, ierr )
622	#else
623	nzb_max = k_top + 1
624	#endif
625	!
626	!-- If topography extents up to the model top, limit nzb_max to nzt.
627	nzb_max = MIN( nzb_max, nzt )
628	!
629	!-- Determine minimum index of topography. Usually, this will be nzb. In case
630	!-- there is elevated topography, however, the lowest topography will be higher.
631	!-- This index is e.g. used to calculate mean first-grid point atmosphere
632	!-- temperature, surface pressure and density, etc. .
633	topo_min_level = 0
634	#if defined( __parallel )
635	CALL MPI_ALLREDUCE( MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
636	topo_min_level, 1, MPI_INTEGER, MPI_MIN, comm2d, ierr )
637	#else
638	topo_min_level = MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
639	#endif
640	!
641	!-- Initialize boundary conditions via surface type
642	CALL init_bc
643
644	!
645	!-- Allocate and set topography height arrays required for data output
646	IF ( TRIM( topography ) /= 'flat' ) THEN
647	!
648	!-- Allocate and set the arrays containing the topography height
649	IF ( nxr == nx .AND. nyn /= ny ) THEN
650	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn), &
651	zw_w_inner(nxl:nxr+1,nys:nyn) )
652	ELSEIF ( nxr /= nx .AND. nyn == ny ) THEN
653	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn+1), &
654	zw_w_inner(nxl:nxr,nys:nyn+1) )
655	ELSEIF ( nxr == nx .AND. nyn == ny ) THEN
656	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn+1), &
657	zw_w_inner(nxl:nxr+1,nys:nyn+1) )
658	ELSE
659	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn), &
660	zw_w_inner(nxl:nxr,nys:nyn) )
661	ENDIF
662
663	zu_s_inner = 0.0_wp
664	zw_w_inner = 0.0_wp
665	!
666	!-- Determine local topography height on scalar and w-grid. Note, setting
667	!-- lateral boundary values is not necessary, realized via wall_flags_0
668	!-- array. Further, please note that loop bounds are different from
669	!-- nxl to nxr and nys to nyn on south and right model boundary, hence,
670	!-- use intrinsic lbound and ubound functions to infer array bounds.
671	DO i = LBOUND(zu_s_inner, 1), UBOUND(zu_s_inner, 1)
672	DO j = LBOUND(zu_s_inner, 2), UBOUND(zu_s_inner, 2)
673	!
674	!-- Topography height on scalar grid. Therefore, determine index of
675	!-- upward-facing surface element on scalar grid.
676	zu_s_inner(i,j) = zu(topo_top_ind(j,i,0))
677	!
678	!-- Topography height on w grid. Therefore, determine index of
679	!-- upward-facing surface element on w grid.
680	zw_w_inner(i,j) = zw(topo_top_ind(j,i,3))
681	ENDDO
682	ENDDO
683	ENDIF
684
685	!
686	!-- In the following, calculate 2D index arrays. Note, these will be removed
687	!-- soon.
688	!-- Allocate outer and inner index arrays for topography and set
689	!-- defaults.
690	ALLOCATE( nzb_s_inner(nysg:nyng,nxlg:nxrg), &
691	nzb_s_outer(nysg:nyng,nxlg:nxrg), &
692	nzb_u_inner(nysg:nyng,nxlg:nxrg), &
693	nzb_u_outer(nysg:nyng,nxlg:nxrg), &
694	nzb_v_inner(nysg:nyng,nxlg:nxrg), &
695	nzb_v_outer(nysg:nyng,nxlg:nxrg), &
696	nzb_w_inner(nysg:nyng,nxlg:nxrg), &
697	nzb_w_outer(nysg:nyng,nxlg:nxrg), &
698	nzb_diff_s_inner(nysg:nyng,nxlg:nxrg), &
699	nzb_diff_s_outer(nysg:nyng,nxlg:nxrg), &
700	nzb_local(nysg:nyng,nxlg:nxrg), &
701	nzb_tmp(nysg:nyng,nxlg:nxrg) )
702	!
703	!-- Initialize 2D-index arrays. Note, these will be removed soon!
704	nzb_local(nys:nyn,nxl:nxr) = topo_top_ind(nys:nyn,nxl:nxr,0)
705	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
706	!
707	!-- Check topography for consistency with model domain. Therefore, use
708	!-- maximum and minium topography-top indices. Note, minimum topography top
709	!-- index is already calculated.
710	IF ( TRIM( topography ) /= 'flat' ) THEN
711	#if defined( __parallel )
712	CALL MPI_ALLREDUCE( MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
713	nzb_local_max, 1, MPI_INTEGER, MPI_MAX, comm2d, ierr )
714	#else
715	nzb_local_max = MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
716	#endif
717	nzb_local_min = topo_min_level
718	!
719	!-- Consistency checks
720	IF ( nzb_local_min < 0 .OR. nzb_local_max > nz + 1 ) THEN
721	WRITE( message_string, * ) 'nzb_local values are outside the', &
722	' model domain', &
723	'&MINVAL( nzb_local ) = ', nzb_local_min, &
724	'&MAXVAL( nzb_local ) = ', nzb_local_max
725	CALL message( 'init_grid', 'PA0210', 1, 2, 0, 6, 0 )
726	ENDIF
727	ENDIF
728
729	nzb_s_inner = nzb; nzb_s_outer = nzb
730	nzb_u_inner = nzb; nzb_u_outer = nzb
731	nzb_v_inner = nzb; nzb_v_outer = nzb
732	nzb_w_inner = nzb; nzb_w_outer = nzb
733
734	!
735	!-- Define vertical gridpoint from (or to) which on the usual finite difference
736	!-- form (which does not use surface fluxes) is applied
737	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
738	nzb_diff = nzb + 2
739	ELSE
740	nzb_diff = nzb + 1
741	ENDIF
742
743	nzb_diff_s_inner = nzb_diff; nzb_diff_s_outer = nzb_diff
744	!
745	!-- Set Neumann conditions for topography. Will be removed soon.
746	IF ( .NOT. bc_ns_cyc ) THEN
747	IF ( nys == 0 ) THEN
748	DO i = 1, nbgp
749	nzb_local(nys-i,:) = nzb_local(nys,:)
750	ENDDO
751	ELSEIF ( nyn == ny ) THEN
752	DO i = 1, nbgp
753	nzb_local(ny+i,:) = nzb_local(ny,:)
754	ENDDO
755	ENDIF
756	ENDIF
757
758	IF ( .NOT. bc_lr_cyc ) THEN
759	IF ( nxl == 0 ) THEN
760	DO i = 1, nbgp
761	nzb_local(:,nxl-i) = nzb_local(:,nxl)
762	ENDDO
763	ELSEIF ( nxr == nx ) THEN
764	DO i = 1, nbgp
765	nzb_local(:,nx+i) = nzb_local(:,nx)
766	ENDDO
767	ENDIF
768	ENDIF
769	!
770	!-- Initialization of 2D index arrays, will be removed soon!
771	!-- Initialize nzb_s_inner and nzb_w_inner
772	nzb_s_inner = nzb_local
773	nzb_w_inner = nzb_local
774
775	!
776	!-- Initialize remaining index arrays:
777	!-- first pre-initialize them with nzb_s_inner...
778	nzb_u_inner = nzb_s_inner
779	nzb_u_outer = nzb_s_inner
780	nzb_v_inner = nzb_s_inner
781	nzb_v_outer = nzb_s_inner
782	nzb_w_outer = nzb_s_inner
783	nzb_s_outer = nzb_s_inner
784
785	!
786	!-- nzb_s_outer:
787	!-- extend nzb_local east-/westwards first, then north-/southwards
788	nzb_tmp = nzb_local
789	DO j = nys, nyn
790	DO i = nxl, nxr
791	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i), &
792	nzb_local(j,i+1) )
793	ENDDO
794	ENDDO
795
796	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
797
798	DO i = nxl, nxr
799	DO j = nys, nyn
800	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
801	nzb_tmp(j+1,i) )
802	ENDDO
803	!
804	!-- non-cyclic boundary conditions (overwritten by call of
805	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
806	IF ( nys == 0 ) THEN
807	j = -1
808	nzb_s_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
809	ENDIF
810	IF ( nyn == ny ) THEN
811	j = ny + 1
812	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
813	ENDIF
814	ENDDO
815	!
816	!-- nzb_w_outer:
817	!-- identical to nzb_s_outer
818	nzb_w_outer = nzb_s_outer
819	!
820	!-- nzb_u_inner:
821	!-- extend nzb_local rightwards only
822	nzb_tmp = nzb_local
823	DO j = nys, nyn
824	DO i = nxl, nxr
825	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i) )
826	ENDDO
827	ENDDO
828
829	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
830
831	nzb_u_inner = nzb_tmp
832	!
833	!-- nzb_u_outer:
834	!-- extend current nzb_tmp (nzb_u_inner) north-/southwards
835	DO i = nxl, nxr
836	DO j = nys, nyn
837	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
838	nzb_tmp(j+1,i) )
839	ENDDO
840	!
841	!-- non-cyclic boundary conditions (overwritten by call of
842	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
843	IF ( nys == 0 ) THEN
844	j = -1
845	nzb_u_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
846	ENDIF
847	IF ( nyn == ny ) THEN
848	j = ny + 1
849	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
850	ENDIF
851	ENDDO
852
853	!
854	!-- nzb_v_inner:
855	!-- extend nzb_local northwards only
856	nzb_tmp = nzb_local
857	DO i = nxl, nxr
858	DO j = nys, nyn
859	nzb_tmp(j,i) = MAX( nzb_local(j-1,i), nzb_local(j,i) )
860	ENDDO
861	ENDDO
862
863	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
864	nzb_v_inner = nzb_tmp
865
866	!
867	!-- nzb_v_outer:
868	!-- extend current nzb_tmp (nzb_v_inner) right-/leftwards
869	DO j = nys, nyn
870	DO i = nxl, nxr
871	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i), &
872	nzb_tmp(j,i+1) )
873	ENDDO
874	!
875	!-- non-cyclic boundary conditions (overwritten by call of
876	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
877	IF ( nxl == 0 ) THEN
878	i = -1
879	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i+1), nzb_tmp(j,i) )
880	ENDIF
881	IF ( nxr == nx ) THEN
882	i = nx + 1
883	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i) )
884	ENDIF
885	ENDDO
886
887	!
888	!-- Exchange of lateral boundary values (parallel computers) and cyclic
889	!-- boundary conditions, if applicable.
890	!-- Since nzb_s_inner and nzb_w_inner are derived directly from nzb_local
891	!-- they do not require exchange and are not included here.
892	CALL exchange_horiz_2d_int( nzb_u_inner, nys, nyn, nxl, nxr, nbgp )
893	CALL exchange_horiz_2d_int( nzb_u_outer, nys, nyn, nxl, nxr, nbgp )
894	CALL exchange_horiz_2d_int( nzb_v_inner, nys, nyn, nxl, nxr, nbgp )
895	CALL exchange_horiz_2d_int( nzb_v_outer, nys, nyn, nxl, nxr, nbgp )
896	CALL exchange_horiz_2d_int( nzb_w_outer, nys, nyn, nxl, nxr, nbgp )
897	CALL exchange_horiz_2d_int( nzb_s_outer, nys, nyn, nxl, nxr, nbgp )
898
899	!
900	!-- Set the individual index arrays which define the k index from which on
901	!-- the usual finite difference form (which does not use surface fluxes) is
902	!-- applied
903	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
904	nzb_diff_s_inner = nzb_s_inner + 2
905	nzb_diff_s_outer = nzb_s_outer + 2
906	ELSE
907	nzb_diff_s_inner = nzb_s_inner + 1
908	nzb_diff_s_outer = nzb_s_outer + 1
909	ENDIF
910	!
911	!-- Vertical nesting: communicate vertical grid level arrays between fine and
912	!-- coarse grid
913	IF ( vnested ) CALL vnest_init_grid
914
915	END SUBROUTINE init_grid
916
917
918	! Description:
919	! -----------------------------------------------------------------------------!
920	!> Calculation of the stretching factor through an iterative method. Ideas were
921	!> taken from the paper "Regional stretched grid generation and its application
922	!> to the NCAR RegCM (1999)". Normally, no analytic solution exists because the
923	!> system of equations has two variables (r,l) but four requirements
924	!> (l=integer, r=[0,88;1,2], Eq(6), Eq(5) starting from index j=1) which
925	!> results into an overdetermined system.
926	!------------------------------------------------------------------------------!
927	SUBROUTINE calculate_stretching_factor( number_end )
928
929	USE control_parameters, &
930	ONLY: dz, dz_stretch_factor_array, &
931	dz_stretch_level_end, dz_stretch_level_start, message_string
932
933	USE kinds
934
935	IMPLICIT NONE
936
937	INTEGER(iwp) :: iterations !< number of iterations until stretch_factor_lower/upper_limit is reached
938	INTEGER(iwp) :: l_rounded !< after l_rounded grid levels dz(n) is strechted to dz(n+1) with stretch_factor_2
939	INTEGER(iwp) :: n !< loop variable for stretching
940
941	INTEGER(iwp), INTENT(IN) :: number_end !< number of user-specified end levels for stretching
942
943	REAL(wp) :: delta_l !< absolute difference between l and l_rounded
944	REAL(wp) :: delta_stretch_factor !< absolute difference between stretch_factor_1 and stretch_factor_2
945	REAL(wp) :: delta_total_new !< sum of delta_l and delta_stretch_factor for the next iteration (should be as small as possible)
946	REAL(wp) :: delta_total_old !< sum of delta_l and delta_stretch_factor for the last iteration
947	REAL(wp) :: distance !< distance between dz_stretch_level_start and dz_stretch_level_end (stretching region)
948	REAL(wp) :: l !< value that fulfil Eq. (5) in the paper mentioned above together with stretch_factor_1 exactly
949	REAL(wp) :: numerator !< numerator of the quotient
950	REAL(wp) :: stretch_factor_1 !< stretching factor that fulfil Eq. (5) togehter with l exactly
951	REAL(wp) :: stretch_factor_2 !< stretching factor that fulfil Eq. (6) togehter with l_rounded exactly
952
953	REAL(wp) :: dz_stretch_factor_array_2(9) = 1.08_wp !< Array that contains all stretch_factor_2 that belongs to stretch_factor_1
954
955	REAL(wp), PARAMETER :: stretch_factor_interval = 1.0E-06 !< interval for sampling possible stretching factors
956	REAL(wp), PARAMETER :: stretch_factor_lower_limit = 0.88 !< lowest possible stretching factor
957	REAL(wp), PARAMETER :: stretch_factor_upper_limit = 1.12 !< highest possible stretching factor
958
959
960	l = 0
961	DO n = 1, number_end
962
963	iterations = 1
964	stretch_factor_1 = 1.0
965	stretch_factor_2 = 1.0
966	delta_total_old = 1.0
967
968	IF ( dz(n) > dz(n+1) ) THEN
969	DO WHILE ( stretch_factor_1 >= stretch_factor_lower_limit )
970
971	stretch_factor_1 = 1.0 - iterations * stretch_factor_interval
972	distance = ABS( dz_stretch_level_end(n) - &
973	dz_stretch_level_start(n) )
974	numerator = distance*stretch_factor_1/dz(n) + &
975	stretch_factor_1 - distance/dz(n)
976
977	IF ( numerator > 0.0 ) THEN
978	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0
979	l_rounded = NINT( l )
980	delta_l = ABS( l_rounded - l ) / l
981	ENDIF
982
983	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
984
985	delta_stretch_factor = ABS( stretch_factor_1 - &
986	stretch_factor_2 ) / &
987	stretch_factor_2
988
989	delta_total_new = delta_l + delta_stretch_factor
990
991	!
992	!-- stretch_factor_1 is taken to guarantee that the stretching
993	!-- procedure ends as close as possible to dz_stretch_level_end.
994	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
995	!-- equal to dz(n+1) after l_rounded grid levels.
996	IF (delta_total_new < delta_total_old) THEN
997	dz_stretch_factor_array(n) = stretch_factor_1
998	dz_stretch_factor_array_2(n) = stretch_factor_2
999	delta_total_old = delta_total_new
1000	ENDIF
1001
1002	iterations = iterations + 1
1003
1004	ENDDO
1005
1006	ELSEIF ( dz(n) < dz(n+1) ) THEN
1007	DO WHILE ( stretch_factor_1 <= stretch_factor_upper_limit )
1008
1009	stretch_factor_1 = 1.0 + iterations * stretch_factor_interval
1010	distance = ABS( dz_stretch_level_end(n) - &
1011	dz_stretch_level_start(n) )
1012	numerator = distance*stretch_factor_1/dz(n) + &
1013	stretch_factor_1 - distance/dz(n)
1014
1015	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0
1016	l_rounded = NINT( l )
1017	delta_l = ABS( l_rounded - l ) / l
1018
1019	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
1020
1021	delta_stretch_factor = ABS( stretch_factor_1 - &
1022	stretch_factor_2 ) / &
1023	stretch_factor_2
1024
1025	delta_total_new = delta_l + delta_stretch_factor
1026
1027	!
1028	!-- stretch_factor_1 is taken to guarantee that the stretching
1029	!-- procedure ends as close as possible to dz_stretch_level_end.
1030	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
1031	!-- equal to dz(n+1) after l_rounded grid levels.
1032	IF (delta_total_new < delta_total_old) THEN
1033	dz_stretch_factor_array(n) = stretch_factor_1
1034	dz_stretch_factor_array_2(n) = stretch_factor_2
1035	delta_total_old = delta_total_new
1036	ENDIF
1037
1038	iterations = iterations + 1
1039	ENDDO
1040
1041	ELSE
1042	message_string= 'Two adjacent values of dz must be different'
1043	CALL message( 'init_grid', 'PA0228', 1, 2, 0, 6, 0 )
1044
1045	ENDIF
1046
1047	!
1048	!-- Check if also the second stretching factor fits into the allowed
1049	!-- interval. If not, print a warning for the user.
1050	IF ( dz_stretch_factor_array_2(n) < stretch_factor_lower_limit .OR. &
1051	dz_stretch_factor_array_2(n) > stretch_factor_upper_limit ) THEN
1052	WRITE( message_string, * ) 'stretch_factor_2 = ', &
1053	dz_stretch_factor_array_2(n), ' which is',&
1054	' responsible for exactly reaching& dz =',&
1055	dz(n+1), 'after a specific amount of', &
1056	' grid levels& exceeds the upper', &
1057	' limit =', stretch_factor_upper_limit, &
1058	' &or lower limit = ', &
1059	stretch_factor_lower_limit
1060	CALL message( 'init_grid', 'PA0499', 0, 1, 0, 6, 0 )
1061
1062	ENDIF
1063	ENDDO
1064
1065	END SUBROUTINE calculate_stretching_factor
1066
1067
1068	! Description:
1069	! -----------------------------------------------------------------------------!
1070	!> Set temporary topography flags and reference buildings on top of underlying
1071	!> orography.
1072	!------------------------------------------------------------------------------!
1073	SUBROUTINE process_topography( topo_3d )
1074
1075	USE arrays_3d, &
1076	ONLY: zu, zw
1077
1078	USE control_parameters, &
1079	ONLY: bc_lr_cyc, bc_ns_cyc, message_string, ocean_mode
1080
1081	USE indices, &
1082	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
1083	nzt
1084
1085	USE netcdf_data_input_mod, &
1086	ONLY: buildings_f, building_id_f, building_type_f, input_pids_static, &
1087	terrain_height_f
1088
1089	USE kinds
1090
1091	USE pegrid
1092
1093	IMPLICIT NONE
1094
1095	INTEGER(iwp) :: i !< running index along x-direction
1096	INTEGER(iwp) :: j !< running index along y-direction
1097	INTEGER(iwp) :: k !< running index along z-direction with respect to numeric grid
1098	INTEGER(iwp) :: k2 !< running index along z-direction with respect to netcdf grid
1099	INTEGER(iwp) :: nr !< index variable indication maximum terrain height for respective building ID
1100	INTEGER(iwp) :: num_build !< counter for number of buildings
1101	INTEGER(iwp) :: topo_top_index !< orography top index, used to map 3D buildings onto terrain
1102
1103	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displace_dum !< displacements of start addresses, used for MPI_ALLGATHERV
1104	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids !< building IDs on entire model domain
1105	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final !< building IDs on entire model domain, multiple occurences are sorted out
1106	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final_tmp !< temporary array used for resizing
1107	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l !< building IDs on local subdomain
1108	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l_tmp !< temporary array used to resize array of building IDs
1109
1110	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings !< number of buildings with different ID on entire model domain
1111	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings_l !< number of buildings with different ID on local subdomain
1112
1113	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< input array for 3D topography and dummy array for setting "outer"-flags
1114
1115	REAL(wp) :: ocean_offset !< offset to consider inverse vertical coordinate at topography definition
1116	REAL(wp) :: oro_min = 0.0_wp !< minimum terrain height in entire model domain, used to reference terrain to zero
1117	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max !< maximum terrain height occupied by an building with certain id
1118	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max_l !< maximum terrain height occupied by an building with certain id, on local subdomain
1119
1120	!
1121	!-- Reference lowest terrain height to zero. In case the minimum terrain height
1122	!-- is non-zero, all grid points of the lower vertical grid levels might be
1123	!-- entirely below the surface, meaning a waste of computational resources.
1124	!-- In order to avoid this, remove the lowest terrain height. Please note,
1125	!-- in case of a nested run, the global minimum from all parent and childs
1126	!-- need to be remove to avoid steep edges at the child-domain boundaries.
1127	IF ( input_pids_static ) THEN
1128
1129	#if defined( __parallel )
1130	CALL MPI_ALLREDUCE( MINVAL( terrain_height_f%var ), oro_min, 1, &
1131	MPI_REAL, MPI_MIN, MPI_COMM_WORLD, ierr )
1132	#else
1133	oro_min = MINVAL( terrain_height_f%var )
1134	#endif
1135	terrain_height_f%var = terrain_height_f%var - oro_min
1136	!
1137	!-- Give an informative message that terrain height is referenced to zero
1138	IF ( oro_min > 0.0_wp ) THEN
1139	WRITE( message_string, * ) 'Terrain height was internally shifted '//&
1140	'downwards by ', oro_min, 'meter(s) to save ' // &
1141	'computational resources.'
1142	CALL message( 'init_grid', 'PA0505', 0, 0, 0, 6, 0 )
1143	ENDIF
1144	ENDIF
1145
1146	!
1147	!-- In the following, buildings and orography are further preprocessed
1148	!-- before they are mapped on the LES grid.
1149	!-- Buildings are mapped on top of the orography by maintaining the roof
1150	!-- shape of the building. This can be achieved by referencing building on
1151	!-- top of the maximum terrain height within the area occupied by the
1152	!-- respective building. As buildings and terrain height are defined PE-wise,
1153	!-- parallelization of this referencing is required (a building can be
1154	!-- distributed between different PEs).
1155	!-- In a first step, determine the number of buildings with different
1156	!-- building id on each PE. In a next step, all building ids are gathered
1157	!-- into one array which is present to all PEs. For each building ID,
1158	!-- the maximum terrain height occupied by the respective building is
1159	!-- computed and distributed to each PE.
1160	!-- Finally, for each building id and its respective reference orography,
1161	!-- builidings are mapped on top.
1162	!--
1163	!-- First, pre-set topography flags, bit 1 indicates orography, bit 2
1164	!-- buildings
1165	!-- classify the respective surfaces.
1166	topo_3d = IBSET( topo_3d, 0 )
1167	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1168	!
1169	!-- In order to map topography on PALM grid also in case of ocean simulations,
1170	!-- pre-calculate an offset value.
1171	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1172	!
1173	!-- Reference buildings on top of orography. This is not necessary
1174	!-- if topography is read from ASCII file as no distinction between buildings
1175	!-- and terrain height can be made. Moreover, this is also not necessary if
1176	!-- urban-surface and land-surface model are used at the same time.
1177	IF ( input_pids_static ) THEN
1178
1179	IF ( buildings_f%from_file ) THEN
1180	num_buildings_l = 0
1181	num_buildings = 0
1182	!
1183	!-- Allocate at least one element for building ids and give it an inital
1184	!-- negative value that will be overwritten later. This, however, is
1185	!-- necessary in case there all IDs in the model domain are fill values.
1186	ALLOCATE( build_ids_l(1) )
1187	build_ids_l = -1
1188	DO i = nxl, nxr
1189	DO j = nys, nyn
1190	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1191	IF ( num_buildings_l(myid) > 0 ) THEN
1192	IF ( ANY( building_id_f%var(j,i) == build_ids_l ) ) &
1193	THEN
1194	CYCLE
1195	ELSE
1196	num_buildings_l(myid) = num_buildings_l(myid) + 1
1197	!
1198	!-- Resize array with different local building ids
1199	ALLOCATE( build_ids_l_tmp(1:SIZE(build_ids_l)) )
1200	build_ids_l_tmp = build_ids_l
1201	DEALLOCATE( build_ids_l )
1202	ALLOCATE( build_ids_l(1:num_buildings_l(myid)) )
1203	build_ids_l(1:num_buildings_l(myid)-1) = &
1204	build_ids_l_tmp(1:num_buildings_l(myid)-1)
1205	build_ids_l(num_buildings_l(myid)) = building_id_f%var(j,i)
1206	DEALLOCATE( build_ids_l_tmp )
1207	ENDIF
1208	!
1209	!-- First occuring building id on PE
1210	ELSE
1211	num_buildings_l(myid) = num_buildings_l(myid) + 1
1212	build_ids_l(1) = building_id_f%var(j,i)
1213	ENDIF
1214	ENDIF
1215	ENDDO
1216	ENDDO
1217	!
1218	!-- Determine number of different building ids for the entire domain
1219	#if defined( __parallel )
1220	CALL MPI_ALLREDUCE( num_buildings_l, num_buildings, numprocs, &
1221	MPI_INTEGER, MPI_SUM, comm2d, ierr )
1222	#else
1223	num_buildings = num_buildings_l
1224	#endif
1225	!
1226	!-- Gather all buildings ids on each PEs.
1227	!-- First, allocate array encompassing all building ids in model domain.
1228	ALLOCATE( build_ids(1:SUM(num_buildings)) )
1229	#if defined( __parallel )
1230	!
1231	!-- Allocate array for displacements.
1232	!-- As each PE may has a different number of buildings, so that
1233	!-- the block sizes send by each PE may not be equal. Hence,
1234	!-- information about the respective displacement is required, indicating
1235	!-- the respective adress where each MPI-task writes into the receive
1236	!-- buffer array
1237	ALLOCATE( displace_dum(0:numprocs-1) )
1238	displace_dum(0) = 0
1239	DO i = 1, numprocs-1
1240	displace_dum(i) = displace_dum(i-1) + num_buildings(i-1)
1241	ENDDO
1242
1243	CALL MPI_ALLGATHERV( build_ids_l(1:num_buildings_l(myid)), &
1244	num_buildings(myid), &
1245	MPI_INTEGER, &
1246	build_ids, &
1247	num_buildings, &
1248	displace_dum, &
1249	MPI_INTEGER, &
1250	comm2d, ierr )
1251
1252	DEALLOCATE( displace_dum )
1253
1254	#else
1255	build_ids = build_ids_l
1256	#endif
1257
1258	!
1259	!-- Note, in parallel mode building ids can occure mutliple times, as
1260	!-- each PE has send its own ids. Therefore, sort out building ids which
1261	!-- appear more than one time.
1262	num_build = 0
1263	DO nr = 1, SIZE(build_ids)
1264
1265	IF ( ALLOCATED(build_ids_final) ) THEN
1266	IF ( ANY( build_ids(nr) == build_ids_final ) ) THEN
1267	CYCLE
1268	ELSE
1269	num_build = num_build + 1
1270	!
1271	!-- Resize
1272	ALLOCATE( build_ids_final_tmp(1:num_build) )
1273	build_ids_final_tmp(1:num_build-1) = build_ids_final(1:num_build-1)
1274	DEALLOCATE( build_ids_final )
1275	ALLOCATE( build_ids_final(1:num_build) )
1276	build_ids_final(1:num_build-1) = build_ids_final_tmp(1:num_build-1)
1277	build_ids_final(num_build) = build_ids(nr)
1278	DEALLOCATE( build_ids_final_tmp )
1279	ENDIF
1280	ELSE
1281	num_build = num_build + 1
1282	ALLOCATE( build_ids_final(1:num_build) )
1283	build_ids_final(num_build) = build_ids(nr)
1284	ENDIF
1285	ENDDO
1286
1287	!
1288	!-- Determine maximumum terrain height occupied by the respective
1289	!-- building and temporalily store on oro_max
1290	ALLOCATE( oro_max_l(1:SIZE(build_ids_final)) )
1291	ALLOCATE( oro_max(1:SIZE(build_ids_final)) )
1292	oro_max_l = 0.0_wp
1293
1294	DO nr = 1, SIZE(build_ids_final)
1295	oro_max_l(nr) = MAXVAL( &
1296	MERGE( terrain_height_f%var(nys:nyn,nxl:nxr), &
1297	0.0_wp, &
1298	building_id_f%var(nys:nyn,nxl:nxr) == &
1299	build_ids_final(nr) ) )
1300	ENDDO
1301
1302	#if defined( __parallel )
1303	IF ( SIZE(build_ids_final) >= 1 ) THEN
1304	CALL MPI_ALLREDUCE( oro_max_l, oro_max, SIZE( oro_max ), MPI_REAL,&
1305	MPI_MAX, comm2d, ierr )
1306	ENDIF
1307	#else
1308	oro_max = oro_max_l
1309	#endif
1310	!
1311	!-- Finally, determine discrete grid height of maximum orography occupied
1312	!-- by a building. Use all-or-nothing approach, i.e. if terrain
1313	!-- exceeds the scalar level the grid box is fully terrain and the
1314	!-- maximum terrain is set to the zw level.
1315	!-- terrain or
1316	oro_max_l = 0.0
1317	DO nr = 1, SIZE(build_ids_final)
1318	DO k = nzb, nzt
1319	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1320	oro_max_l(nr) = zw(k) - ocean_offset
1321	ENDDO
1322	oro_max(nr) = oro_max_l(nr)
1323	ENDDO
1324	ENDIF
1325	!
1326	!-- Allocate array for storing terrain height under buildings
1327	IF ( buildings_f%from_file ) THEN
1328	ALLOCATE( buildings_f%oro_max(nysg:nyng,nxlg:nxrg) )
1329	buildings_f%oro_max = buildings_f%fill1
1330	END IF
1331	!
1332	!-- Map orography as well as buildings onto grid.
1333	DO i = nxl, nxr
1334	DO j = nys, nyn
1335	topo_top_index = 0
1336	!
1337	!-- Obtain index in global building_id array
1338	IF ( buildings_f%from_file ) THEN
1339	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1340	!
1341	!-- Determine index where maximum terrain height occupied by
1342	!-- the respective building height is stored.
1343	nr = MINLOC( ABS( build_ids_final - &
1344	building_id_f%var(j,i) ), DIM = 1 )
1345	!
1346	!-- Save grid-indexed oro_max
1347	buildings_f%oro_max(j,i) = oro_max(nr)
1348	ENDIF
1349	ENDIF
1350	DO k = nzb, nzt
1351	!
1352	!-- In a first step, if grid point is below or equal the given
1353	!-- terrain height, grid point is flagged to be of type natural.
1354	!-- Please note, in case there is also a building which is lower
1355	!-- than the vertical grid spacing, initialization of surface
1356	!-- attributes will not be correct as given surface information
1357	!-- will not be in accordance to the classified grid points.
1358	!-- Hence, in this case, also a building flag.
1359	IF ( zu(k) - ocean_offset <= terrain_height_f%var(j,i) ) THEN
1360	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1361	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1362	topo_top_index = k ! topo_top_index + 1
1363	ENDIF
1364	!
1365	!-- Set building grid points. Here, only consider 2D buildings.
1366	!-- 3D buildings require separate treatment.
1367	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1368	!
1369	!-- Fill-up the terrain to the level of maximum orography
1370	!-- within the building-covered area.
1371	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1372	!
1373	!-- Note, oro_max is always on zw level
1374	IF ( zu(k) - ocean_offset < oro_max(nr) ) THEN
1375	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1376	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1377	ELSEIF ( zu(k) - ocean_offset <= &
1378	oro_max(nr) + buildings_f%var_2d(j,i) ) THEN
1379	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1380	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1381	ENDIF
1382	ENDIF
1383	ENDIF
1384	ENDDO
1385	!
1386	!-- Special treatment for non grid-resolved buildings. This case,
1387	!-- the uppermost terrain grid point is flagged as building as well
1388	!-- well, even though no building exists at all. However, the
1389	!-- surface element will be identified as urban-surface and the
1390	!-- input data provided by the drivers is consistent to the surface
1391	!-- classification. Else, all non grid-resolved buildings would vanish
1392	!-- and identified as terrain grid points, which, however, won't be
1393	!-- consistent with the input data.
1394	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1395	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1396	DO k = nzb, nzt
1397	IF( zw(k) - ocean_offset == oro_max(nr) ) THEN
1398	IF ( buildings_f%var_2d(j,i) <= zu(k+1) - zw(k) ) THEN
1399	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1400	ENDIF
1401	ENDIF
1402	ENDDO
1403	ENDIF
1404	ENDIF
1405	!
1406	!-- Map 3D buildings onto terrain height.
1407	!-- In case of any slopes, map building on top of maximum terrain
1408	!-- height covered by the building. In other words, extend
1409	!-- building down to the respective local terrain-surface height.
1410	IF ( buildings_f%from_file .AND. buildings_f%lod == 2 ) THEN
1411	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1412	!
1413	!-- Extend building down to the terrain surface, i.e. fill-up
1414	!-- surface irregularities below a building. Note, oro_max
1415	!-- is already a discrete height according to the all-or-nothing
1416	!-- approach, i.e. grid box is either topography or atmosphere,
1417	!-- terrain top is defined at upper bound of the grid box.
1418	!-- Hence, check for zw in this case.
1419	!-- Note, do this only for buildings which are surface mounted,
1420	!-- i.e. building types 1-6. Below bridges, which are represented
1421	!-- exclusively by building type 7, terrain shape should be
1422	!-- maintained.
1423	IF ( building_type_f%from_file ) THEN
1424	IF ( building_type_f%var(j,i) /= 7 ) THEN
1425	DO k = topo_top_index + 1, nzt + 1
1426	IF ( zu(k) - ocean_offset <= oro_max(nr) ) THEN
1427	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1428	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1429	ENDIF
1430	ENDDO
1431	!
1432	!-- After surface irregularities are smoothen, determine
1433	!-- lower start index where building starts.
1434	DO k = nzb, nzt
1435	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1436	topo_top_index = k
1437	ENDDO
1438	ENDIF
1439	ENDIF
1440	!
1441	!-- Finally, map building on top.
1442	k2 = 0
1443	DO k = topo_top_index, nzt + 1
1444	IF ( k2 <= buildings_f%nz-1 ) THEN
1445	IF ( buildings_f%var_3d(k2,j,i) == 1 ) THEN
1446	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1447	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1448	ENDIF
1449	ENDIF
1450	k2 = k2 + 1
1451	ENDDO
1452	ENDIF
1453	ENDIF
1454	ENDDO
1455	ENDDO
1456	!
1457	!-- Horizontal exchange the oro_max array, which is required to for
1458	!-- initialization of building-surface properties.
1459	IF ( ALLOCATED( buildings_f%oro_max ) ) THEN
1460	CALL exchange_horiz_2d( buildings_f%oro_max(:,:), nbgp )
1461	ENDIF
1462	!
1463	!-- Deallocate temporary arrays required for processing and reading data
1464	IF ( ALLOCATED( oro_max ) ) DEALLOCATE( oro_max )
1465	IF ( ALLOCATED( oro_max_l ) ) DEALLOCATE( oro_max_l )
1466	IF ( ALLOCATED( build_ids_final ) ) DEALLOCATE( build_ids_final )
1467	!
1468	!-- Topography input via ASCII format.
1469	ELSE
1470	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1471	!
1472	!-- Initialize topography bit 0 (indicates obstacle) everywhere to zero
1473	!-- and clear all grid points at nzb, where alway a surface is defined.
1474	!-- Further, set also bit 1 (indicates terrain) at nzb, which is further
1475	!-- used for masked data output and further processing. Note, in the
1476	!-- ASCII case no distinction is made between buildings and terrain,
1477	!-- so that setting of bit 1 and 2 at the same time has no effect.
1478	topo_3d = IBSET( topo_3d, 0 )
1479	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1480	topo_3d(nzb,:,:) = IBSET( topo_3d(nzb,:,:), 1 )
1481	DO i = nxl, nxr
1482	DO j = nys, nyn
1483	DO k = nzb, nzt
1484	!
1485	!-- Flag topography for all grid points which are below
1486	!-- the local topography height.
1487	!-- Note, each topography is flagged as building.
1488	IF ( zu(k) - ocean_offset <= buildings_f%var_2d(j,i) ) THEN
1489	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1490	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 ) !indicates building
1491	ENDIF
1492	ENDDO
1493	ENDDO
1494	ENDDO
1495	ENDIF
1496
1497	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1498
1499	IF ( .NOT. bc_ns_cyc ) THEN
1500	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1501	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1502	ENDIF
1503
1504	IF ( .NOT. bc_lr_cyc ) THEN
1505	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1506	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1507	ENDIF
1508
1509	END SUBROUTINE process_topography
1510
1511
1512	! Description:
1513	! -----------------------------------------------------------------------------!
1514	!> Filter topography, i.e. fill holes resolved by only one grid point.
1515	!> Such holes are suspected to lead to velocity blow-ups as continuity
1516	!> equation on discrete grid cannot be fulfilled in such case.
1517	!------------------------------------------------------------------------------!
1518	SUBROUTINE filter_topography( topo_3d )
1519
1520	USE control_parameters, &
1521	ONLY: bc_lr_cyc, bc_ns_cyc, message_string
1522
1523	USE indices, &
1524	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt
1525
1526	USE netcdf_data_input_mod, &
1527	ONLY: building_id_f, building_type_f
1528
1529	USE pegrid
1530
1531	IMPLICIT NONE
1532
1533	LOGICAL :: filled = .FALSE. !< flag indicating if holes were filled
1534
1535	INTEGER(iwp) :: i !< running index along x-direction
1536	INTEGER(iwp) :: j !< running index along y-direction
1537	INTEGER(iwp) :: k !< running index along z-direction
1538	INTEGER(iwp) :: num_hole !< number of holes (in topography) resolved by only one grid point
1539	INTEGER(iwp) :: num_hole_l !< number of holes (in topography) resolved by only one grid point on local PE
1540	INTEGER(iwp) :: num_wall !< number of surrounding vertical walls for a single grid point
1541
1542	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo_tmp !< temporary 3D-topography used to fill holes
1543	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< 3D-topography array merging buildings and orography
1544	!
1545	!-- Before checking for holes, set lateral boundary conditions for
1546	!-- topography. After hole-filling, boundary conditions must be set again.
1547	!-- Several iterations are performed, in order to fill holes which might
1548	!-- emerge by the filling-algorithm itself.
1549	ALLOCATE( topo_tmp(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
1550	topo_tmp = 0
1551
1552	num_hole = 99999
1553	DO WHILE ( num_hole > 0 )
1554
1555	num_hole = 0
1556	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1557	!
1558	!-- Exchange also building ID and type. Note, building_type is an one-byte
1559	!-- variable.
1560	IF ( building_id_f%from_file ) &
1561	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1562	IF ( building_type_f%from_file ) &
1563	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1564
1565	topo_tmp = topo_3d
1566	!
1567	!-- In case of non-cyclic lateral boundaries, assume lateral boundary to be
1568	!-- a solid wall. Thus, intermediate spaces of one grid point between
1569	!-- boundary and some topographic structure will be filled.
1570	IF ( .NOT. bc_ns_cyc ) THEN
1571	IF ( nys == 0 ) topo_tmp(:,-1,:) = IBCLR( topo_tmp(:,0,:), 0 )
1572	IF ( nyn == ny ) topo_tmp(:,ny+1,:) = IBCLR( topo_tmp(:,ny,:), 0 )
1573	ENDIF
1574
1575	IF ( .NOT. bc_lr_cyc ) THEN
1576	IF ( nxl == 0 ) topo_tmp(:,:,-1) = IBCLR( topo_tmp(:,:,0), 0 )
1577	IF ( nxr == nx ) topo_tmp(:,:,nx+1) = IBCLR( topo_tmp(:,:,nx), 0 )
1578	ENDIF
1579
1580	num_hole_l = 0
1581	DO i = nxl, nxr
1582	DO j = nys, nyn
1583	DO k = nzb+1, nzt
1584	IF ( BTEST( topo_tmp(k,j,i), 0 ) ) THEN
1585	num_wall = 0
1586	IF ( .NOT. BTEST( topo_tmp(k,j-1,i), 0 ) ) &
1587	num_wall = num_wall + 1
1588	IF ( .NOT. BTEST( topo_tmp(k,j+1,i), 0 ) ) &
1589	num_wall = num_wall + 1
1590	IF ( .NOT. BTEST( topo_tmp(k,j,i-1), 0 ) ) &
1591	num_wall = num_wall + 1
1592	IF ( .NOT. BTEST( topo_tmp(k,j,i+1), 0 ) ) &
1593	num_wall = num_wall + 1
1594	IF ( .NOT. BTEST( topo_tmp(k-1,j,i), 0 ) ) &
1595	num_wall = num_wall + 1
1596	IF ( .NOT. BTEST( topo_tmp(k+1,j,i), 0 ) ) &
1597	num_wall = num_wall + 1
1598
1599	IF ( num_wall >= 4 ) THEN
1600	num_hole_l = num_hole_l + 1
1601	!
1602	!-- Clear flag 0 and set special flag ( bit 3) to indicate
1603	!-- that new topography point is a result of filtering process.
1604	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1605	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 3 )
1606	!
1607	!-- If filled grid point is occupied by a building, classify
1608	!-- it as building grid point.
1609	IF ( building_type_f%from_file ) THEN
1610	IF ( building_type_f%var(j,i) /= &
1611	building_type_f%fill .OR. &
1612	building_type_f%var(j+1,i) /= &
1613	building_type_f%fill .OR. &
1614	building_type_f%var(j-1,i) /= &
1615	building_type_f%fill .OR. &
1616	building_type_f%var(j,i+1) /= &
1617	building_type_f%fill .OR. &
1618	building_type_f%var(j,i-1) /= &
1619	building_type_f%fill ) THEN
1620	!
1621	!-- Set flag indicating building surfaces
1622	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1623	!
1624	!-- Set building_type and ID at this position if not
1625	!-- already set. This is required for proper
1626	!-- initialization of urban-surface energy balance
1627	!-- solver.
1628	IF ( building_type_f%var(j,i) == &
1629	building_type_f%fill ) THEN
1630
1631	IF ( building_type_f%var(j+1,i) /= &
1632	building_type_f%fill ) THEN
1633	building_type_f%var(j,i) = &
1634	building_type_f%var(j+1,i)
1635	building_id_f%var(j,i) = &
1636	building_id_f%var(j+1,i)
1637	ELSEIF ( building_type_f%var(j-1,i) /= &
1638	building_type_f%fill ) THEN
1639	building_type_f%var(j,i) = &
1640	building_type_f%var(j-1,i)
1641	building_id_f%var(j,i) = &
1642	building_id_f%var(j-1,i)
1643	ELSEIF ( building_type_f%var(j,i+1) /= &
1644	building_type_f%fill ) THEN
1645	building_type_f%var(j,i) = &
1646	building_type_f%var(j,i+1)
1647	building_id_f%var(j,i) = &
1648	building_id_f%var(j,i+1)
1649	ELSEIF ( building_type_f%var(j,i-1) /= &
1650	building_type_f%fill ) THEN
1651	building_type_f%var(j,i) = &
1652	building_type_f%var(j,i-1)
1653	building_id_f%var(j,i) = &
1654	building_id_f%var(j,i-1)
1655	ENDIF
1656	ENDIF
1657	ENDIF
1658	ENDIF
1659	!
1660	!-- If filled grid point is already classified as building
1661	!-- everything is fine, else classify this grid point as
1662	!-- natural type grid point. This case, values for the
1663	!-- surface type are already set.
1664	IF ( .NOT. BTEST( topo_3d(k,j,i), 2 ) ) THEN
1665	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1666	ENDIF
1667	ENDIF
1668	ENDIF
1669	ENDDO
1670	ENDDO
1671	ENDDO
1672	!
1673	!-- Count the total number of holes, required for informative message.
1674	#if defined( __parallel )
1675	CALL MPI_ALLREDUCE( num_hole_l, num_hole, 1, MPI_INTEGER, MPI_SUM, &
1676	comm2d, ierr )
1677	#else
1678	num_hole = num_hole_l
1679	#endif
1680	IF ( num_hole > 0 .AND. .NOT. filled ) filled = .TRUE.
1681
1682	ENDDO
1683	!
1684	!-- Create an informative message if any holes were filled.
1685	IF ( filled ) THEN
1686	WRITE( message_string, * ) 'Topography was filtered, i.e. holes ' // &
1687	'resolved by only one grid point ' // &
1688	'were filled during initialization.'
1689	CALL message( 'init_grid', 'PA0430', 0, 0, 0, 6, 0 )
1690	ENDIF
1691
1692	DEALLOCATE( topo_tmp )
1693	!
1694	!-- Finally, exchange topo_3d array again and if necessary set Neumann boundary
1695	!-- condition in case of non-cyclic lateral boundaries.
1696	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1697
1698	IF ( .NOT. bc_ns_cyc ) THEN
1699	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1700	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1701	ENDIF
1702
1703	IF ( .NOT. bc_lr_cyc ) THEN
1704	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1705	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1706	ENDIF
1707	!
1708	!-- Exchange building ID and type. Note, building_type is an one-byte variable.
1709	IF ( building_id_f%from_file ) &
1710	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1711	IF ( building_type_f%from_file ) &
1712	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1713
1714	END SUBROUTINE filter_topography
1715
1716
1717	! Description:
1718	! -----------------------------------------------------------------------------!
1719	!> Reads topography information from file or sets generic topography. Moreover,
1720	!> all topography-relevant topography arrays are initialized, and grid flags
1721	!> are set.
1722	!------------------------------------------------------------------------------!
1723	SUBROUTINE init_topo( topo )
1724
1725	USE arrays_3d, &
1726	ONLY: zw
1727
1728	USE control_parameters, &
1729	ONLY: bc_lr_cyc, bc_ns_cyc, building_height, building_length_x, &
1730	building_length_y, building_wall_left, building_wall_south, &
1731	canyon_height, canyon_wall_left, canyon_wall_south, &
1732	canyon_width_x, canyon_width_y, dp_level_ind_b, dz, &
1733	message_string, topography, topography_grid_convention, &
1734	tunnel_height, tunnel_length, tunnel_width_x, tunnel_width_y, &
1735	tunnel_wall_depth
1736
1737	USE grid_variables, &
1738	ONLY: dx, dy
1739
1740	USE indices, &
1741	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
1742	nzb, nzt
1743
1744	USE kinds
1745
1746	USE netcdf_data_input_mod, &
1747	ONLY: buildings_f, terrain_height_f
1748
1749	USE pegrid
1750
1751	IMPLICIT NONE
1752
1753	INTEGER(iwp) :: bh !< temporary vertical index of building height
1754	INTEGER(iwp) :: blx !< grid point number of building size along x
1755	INTEGER(iwp) :: bly !< grid point number of building size along y
1756	INTEGER(iwp) :: bxl !< index for left building wall
1757	INTEGER(iwp) :: bxr !< index for right building wall
1758	INTEGER(iwp) :: byn !< index for north building wall
1759	INTEGER(iwp) :: bys !< index for south building wall
1760	INTEGER(iwp) :: ch !< temporary vertical index for canyon height
1761	INTEGER(iwp) :: cwx !< grid point number of canyon size along x
1762	INTEGER(iwp) :: cwy !< grid point number of canyon size along y
1763	INTEGER(iwp) :: cxl !< index for left canyon wall
1764	INTEGER(iwp) :: cxr !< index for right canyon wall
1765	INTEGER(iwp) :: cyn !< index for north canyon wall
1766	INTEGER(iwp) :: cys !< index for south canyon wall
1767	INTEGER(iwp) :: i !< index variable along x
1768	INTEGER(iwp) :: j !< index variable along y
1769	INTEGER(iwp) :: k !< index variable along z
1770	INTEGER(iwp) :: hv_in !< heavyside function to model inner tunnel surface
1771	INTEGER(iwp) :: hv_out !< heavyside function to model outer tunnel surface
1772	INTEGER(iwp) :: txe_out !< end position of outer tunnel wall in x
1773	INTEGER(iwp) :: txs_out !< start position of outer tunnel wall in x
1774	INTEGER(iwp) :: tye_out !< end position of outer tunnel wall in y
1775	INTEGER(iwp) :: tys_out !< start position of outer tunnel wall in y
1776	INTEGER(iwp) :: txe_in !< end position of inner tunnel wall in x
1777	INTEGER(iwp) :: txs_in !< start position of inner tunnel wall in x
1778	INTEGER(iwp) :: tye_in !< end position of inner tunnel wall in y
1779	INTEGER(iwp) :: tys_in !< start position of inner tunnel wall in y
1780	INTEGER(iwp) :: td !< tunnel wall depth
1781	INTEGER(iwp) :: th !< height of outer tunnel wall
1782
1783	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
1784	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
1785	!
1786	!-- Check for correct setting of the namelist parameter topography. If
1787	!-- topography information is read from file but topography = 'flat',
1788	!-- initialization does not properly.
1789	IF ( ( buildings_f%from_file .OR. terrain_height_f%from_file ) .AND. &
1790	TRIM( topography ) /= 'read_from_file' ) THEN
1791	message_string = 'If topography information is provided (via ' // &
1792	'Netcdf or ASCII input) topography = ' // &
1793	'"read_from_file" is required.'
1794	CALL message( 'init_grid', 'PA0437', 1, 2, 0, 6, 0 )
1795	ENDIF
1796	!
1797	!-- Set outer and inner index arrays for non-flat topography.
1798	!-- Here consistency checks concerning domain size and periodicity are
1799	!-- necessary.
1800	!-- Within this SELECT CASE structure only nzb_local is initialized
1801	!-- individually depending on the chosen topography type, all other index
1802	!-- arrays are initialized further below.
1803	SELECT CASE ( TRIM( topography ) )
1804
1805	CASE ( 'flat' )
1806	!
1807	!-- Initialilize 3D topography array, used later for initializing flags
1808	topo(nzb+1:nzt+1,:,:) = IBSET( topo(nzb+1:nzt+1,:,:), 0 )
1809
1810	CASE ( 'single_building' )
1811	!
1812	!-- Single rectangular building, by default centered in the middle of the
1813	!-- total domain
1814	blx = NINT( building_length_x / dx )
1815	bly = NINT( building_length_y / dy )
1816	bh = MINLOC( ABS( zw - building_height ), 1 ) - 1
1817	IF ( ABS( zw(bh) - building_height ) == &
1818	ABS( zw(bh+1) - building_height ) ) bh = bh + 1
1819	IF ( building_wall_left == 9999999.9_wp ) THEN
1820	building_wall_left = ( nx + 1 - blx ) / 2 * dx
1821	ENDIF
1822	bxl = NINT( building_wall_left / dx )
1823	bxr = bxl + blx
1824
1825	IF ( building_wall_south == 9999999.9_wp ) THEN
1826	building_wall_south = ( ny + 1 - bly ) / 2 * dy
1827	ENDIF
1828	bys = NINT( building_wall_south / dy )
1829	byn = bys + bly
1830
1831	!
1832	!-- Building size has to meet some requirements
1833	IF ( ( bxl < 1 ) .OR. ( bxr > nx-1 ) .OR. ( bxr < bxl+3 ) .OR. &
1834	( bys < 1 ) .OR. ( byn > ny-1 ) .OR. ( byn < bys+3 ) ) THEN
1835	WRITE( message_string, * ) 'inconsistent building parameters:', &
1836	'&bxl=', bxl, 'bxr=', bxr, 'bys=', bys, &
1837	'byn=', byn, 'nx=', nx, 'ny=', ny
1838	CALL message( 'init_grid', 'PA0203', 1, 2, 0, 6, 0 )
1839	ENDIF
1840
1841	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1842	nzb_local = 0
1843	!
1844	!-- Define the building.
1845	IF ( bxl <= nxr .AND. bxr >= nxl .AND. &
1846	bys <= nyn .AND. byn >= nys ) &
1847	nzb_local(MAX(nys,bys):MIN(nyn,byn),MAX(nxl,bxl):MIN(nxr,bxr)) = bh
1848	!
1849	!-- Set bit array on basis of nzb_local
1850	DO i = nxl, nxr
1851	DO j = nys, nyn
1852	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1853	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1854	ENDDO
1855	ENDDO
1856
1857	DEALLOCATE( nzb_local )
1858
1859	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1860	!
1861	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1862	!-- boundary conditions for topography.
1863	IF ( .NOT. bc_ns_cyc ) THEN
1864	IF ( nys == 0 ) THEN
1865	DO i = 1, nbgp
1866	topo(:,nys-i,:) = topo(:,nys,:)
1867	ENDDO
1868	ENDIF
1869	IF ( nyn == ny ) THEN
1870	DO i = 1, nbgp
1871	topo(:,nyn+i,:) = topo(:,nyn,:)
1872	ENDDO
1873	ENDIF
1874	ENDIF
1875	IF ( .NOT. bc_lr_cyc ) THEN
1876	IF ( nxl == 0 ) THEN
1877	DO i = 1, nbgp
1878	topo(:,:,nxl-i) = topo(:,:,nxl)
1879	ENDDO
1880	ENDIF
1881	IF ( nxr == nx ) THEN
1882	DO i = 1, nbgp
1883	topo(:,:,nxr+i) = topo(:,:,nxr)
1884	ENDDO
1885	ENDIF
1886	ENDIF
1887
1888	CASE ( 'single_street_canyon' )
1889	!
1890	!-- Single quasi-2D street canyon of infinite length in x or y direction.
1891	!-- The canyon is centered in the other direction by default.
1892	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1893	!
1894	!-- Street canyon in y direction
1895	cwx = NINT( canyon_width_x / dx )
1896	IF ( canyon_wall_left == 9999999.9_wp ) THEN
1897	canyon_wall_left = ( nx + 1 - cwx ) / 2 * dx
1898	ENDIF
1899	cxl = NINT( canyon_wall_left / dx )
1900	cxr = cxl + cwx
1901	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1902	!
1903	!-- Street canyon in x direction
1904	cwy = NINT( canyon_width_y / dy )
1905	IF ( canyon_wall_south == 9999999.9_wp ) THEN
1906	canyon_wall_south = ( ny + 1 - cwy ) / 2 * dy
1907	ENDIF
1908	cys = NINT( canyon_wall_south / dy )
1909	cyn = cys + cwy
1910
1911	ELSE
1912
1913	message_string = 'no street canyon width given'
1914	CALL message( 'init_grid', 'PA0204', 1, 2, 0, 6, 0 )
1915
1916	ENDIF
1917
1918	ch = MINLOC( ABS( zw - canyon_height ), 1 ) - 1
1919	IF ( ABS( zw(ch) - canyon_height ) == &
1920	ABS( zw(ch+1) - canyon_height ) ) ch = ch + 1
1921	dp_level_ind_b = ch
1922	!
1923	!-- Street canyon size has to meet some requirements
1924	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1925	IF ( ( cxl < 1 ) .OR. ( cxr > nx-1 ) .OR. ( cwx < 3 ) .OR. &
1926	( ch < 3 ) ) THEN
1927	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1928	'&cxl=', cxl, ' cxr=', cxr, &
1929	' cwx=', cwx, &
1930	' ch=', ch, ' nx=', nx, ' ny=', ny
1931	CALL message( 'init_grid', 'PA0205', 1, 2, 0, 6, 0 )
1932	ENDIF
1933	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1934	IF ( ( cys < 1 ) .OR. ( cyn > ny-1 ) .OR. ( cwy < 3 ) .OR. &
1935	( ch < 3 ) ) THEN
1936	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1937	'&cys=', cys, ' cyn=', cyn, &
1938	' cwy=', cwy, &
1939	' ch=', ch, ' nx=', nx, ' ny=', ny
1940	CALL message( 'init_grid', 'PA0206', 1, 2, 0, 6, 0 )
1941	ENDIF
1942	ENDIF
1943	IF ( canyon_width_x /= 9999999.9_wp .AND. &
1944	canyon_width_y /= 9999999.9_wp ) THEN
1945	message_string = 'inconsistent canyon parameters:' // &
1946	'&street canyon can only be oriented' // &
1947	' either in x- or in y-direction'
1948	CALL message( 'init_grid', 'PA0207', 1, 2, 0, 6, 0 )
1949	ENDIF
1950
1951	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1952	nzb_local = ch
1953	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1954	IF ( cxl <= nxr .AND. cxr >= nxl ) &
1955	nzb_local(:,MAX(nxl,cxl+1):MIN(nxr,cxr-1)) = 0
1956	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1957	IF ( cys <= nyn .AND. cyn >= nys ) &
1958	nzb_local(MAX(nys,cys+1):MIN(nyn,cyn-1),:) = 0
1959	ENDIF
1960	!
1961	!-- Set bit array on basis of nzb_local
1962	DO i = nxl, nxr
1963	DO j = nys, nyn
1964	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1965	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1966	ENDDO
1967	ENDDO
1968	DEALLOCATE( nzb_local )
1969
1970	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1971	!
1972	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1973	!-- boundary conditions for topography.
1974	IF ( .NOT. bc_ns_cyc ) THEN
1975	IF ( nys == 0 ) THEN
1976	DO i = 1, nbgp
1977	topo(:,nys-i,:) = topo(:,nys,:)
1978	ENDDO
1979	ENDIF
1980	IF ( nyn == ny ) THEN
1981	DO i = 1, nbgp
1982	topo(:,nyn+i,:) = topo(:,nyn,:)
1983	ENDDO
1984	ENDIF
1985	ENDIF
1986	IF ( .NOT. bc_lr_cyc ) THEN
1987	IF ( nxl == 0 ) THEN
1988	DO i = 1, nbgp
1989	topo(:,:,nxl-i) = topo(:,:,nxl)
1990	ENDDO
1991	ENDIF
1992	IF ( nxr == nx ) THEN
1993	DO i = 1, nbgp
1994	topo(:,:,nxr+i) = topo(:,:,nxr)
1995	ENDDO
1996	ENDIF
1997	ENDIF
1998
1999	CASE ( 'tunnel' )
2000
2001	!
2002	!-- Tunnel height
2003	IF ( tunnel_height == 9999999.9_wp ) THEN
2004	th = zw( INT( 0.2 * nz) )
2005	ELSE
2006	th = tunnel_height
2007	ENDIF
2008	!
2009	!-- Tunnel-wall depth
2010	IF ( tunnel_wall_depth == 9999999.9_wp ) THEN
2011	td = MAX ( dx, dy, dz(1) )
2012	ELSE
2013	td = tunnel_wall_depth
2014	ENDIF
2015	!
2016	!-- Check for tunnel width
2017	IF ( tunnel_width_x == 9999999.9_wp .AND. &
2018	tunnel_width_y == 9999999.9_wp ) THEN
2019	message_string = 'No tunnel width is given. '
2020	CALL message( 'init_grid', 'PA0280', 1, 2, 0, 6, 0 )
2021	ENDIF
2022	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
2023	tunnel_width_y /= 9999999.9_wp ) THEN
2024	message_string = 'Inconsistent tunnel parameters:' // &
2025	'tunnel can only be oriented' // &
2026	'either in x- or in y-direction.'
2027	CALL message( 'init_grid', 'PA0281', 1, 2, 0, 6, 0 )
2028	ENDIF
2029	!
2030	!-- Tunnel axis along y
2031	IF ( tunnel_width_x /= 9999999.9_wp ) THEN
2032	IF ( tunnel_width_x > ( nx + 1 ) * dx ) THEN
2033	message_string = 'Tunnel width too large'
2034	CALL message( 'init_grid', 'PA0282', 1, 2, 0, 6, 0 )
2035	ENDIF
2036
2037	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_width_x * 0.5_wp )
2038	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_width_x * 0.5_wp )
2039	txs_in = INT( ( nx + 1 ) * 0.5_wp * dx - &
2040	( tunnel_width_x * 0.5_wp - td ) )
2041	txe_in = INT( ( nx + 1 ) * 0.5_wp * dx + &
2042	( tunnel_width_x * 0.5_wp - td ) )
2043
2044	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_length * 0.5_wp )
2045	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_length * 0.5_wp )
2046	tys_in = tys_out
2047	tye_in = tye_out
2048	ENDIF
2049	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
2050	tunnel_width_x - 2.0_wp * td <= 2.0_wp * dx ) &
2051	THEN
2052	message_string = 'Tunnel width too small'
2053	CALL message( 'init_grid', 'PA0175', 1, 2, 0, 6, 0 )
2054	ENDIF
2055	IF ( tunnel_width_y /= 9999999.9_wp .AND. &
2056	tunnel_width_y - 2.0_wp * td <= 2.0_wp * dy ) &
2057	THEN
2058	message_string = 'Tunnel width too small'
2059	CALL message( 'init_grid', 'PA0455', 1, 2, 0, 6, 0 )
2060	ENDIF
2061	!
2062	!-- Tunnel axis along x
2063	IF ( tunnel_width_y /= 9999999.9_wp ) THEN
2064	IF ( tunnel_width_y > ( ny + 1 ) * dy ) THEN
2065	message_string = 'Tunnel width too large'
2066	CALL message( 'init_grid', 'PA0456', 1, 2, 0, 6, 0 )
2067	ENDIF
2068
2069	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_length * 0.5_wp )
2070	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_length * 0.5_wp )
2071	txs_in = txs_out
2072	txe_in = txe_out
2073
2074	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_width_y * 0.5_wp )
2075	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_width_y * 0.5_wp )
2076	tys_in = INT( ( ny + 1 ) * 0.5_wp * dy - &
2077	( tunnel_width_y * 0.5_wp - td ) )
2078	tye_in = INT( ( ny + 1 ) * 0.5_wp * dy + &
2079	( tunnel_width_y * 0.5_wp - td ) )
2080	ENDIF
2081
2082	topo = 0
2083	DO i = nxl, nxr
2084	DO j = nys, nyn
2085	!
2086	!-- Use heaviside function to model outer tunnel surface
2087	hv_out = th * 0.5_wp * &
2088	( ( SIGN( 1.0_wp, i * dx - txs_out ) + 1.0_wp ) &
2089	- ( SIGN( 1.0_wp, i * dx - txe_out ) + 1.0_wp ) )
2090
2091	hv_out = hv_out * 0.5_wp * &
2092	( ( SIGN( 1.0_wp, j * dy - tys_out ) + 1.0_wp ) &
2093	- ( SIGN( 1.0_wp, j * dy - tye_out ) + 1.0_wp ) )
2094	!
2095	!-- Use heaviside function to model inner tunnel surface
2096	hv_in = ( th - td ) * 0.5_wp * &
2097	( ( SIGN( 1.0_wp, i * dx - txs_in ) + 1.0_wp ) &
2098	- ( SIGN( 1.0_wp, i * dx - txe_in ) + 1.0_wp ) )
2099
2100	hv_in = hv_in * 0.5_wp * &
2101	( ( SIGN( 1.0_wp, j * dy - tys_in ) + 1.0_wp ) &
2102	- ( SIGN( 1.0_wp, j * dy - tye_in ) + 1.0_wp ) )
2103	!
2104	!-- Set flags at x-y-positions without any tunnel surface
2105	IF ( hv_out - hv_in == 0.0_wp ) THEN
2106	topo(nzb+1:nzt+1,j,i) = IBSET( topo(nzb+1:nzt+1,j,i), 0 )
2107	!
2108	!-- Set flags at x-y-positions with tunnel surfaces
2109	ELSE
2110	DO k = nzb + 1, nzt + 1
2111	!
2112	!-- Inner tunnel
2113	IF ( hv_out - hv_in == th ) THEN
2114	IF ( zw(k) <= hv_out ) THEN
2115	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
2116	ELSE
2117	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2118	ENDIF
2119	ENDIF
2120	!
2121	!-- Lateral tunnel walls
2122	IF ( hv_out - hv_in == td ) THEN
2123	IF ( zw(k) <= hv_in ) THEN
2124	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2125	ELSEIF ( zw(k) > hv_in .AND. zw(k) <= hv_out ) THEN
2126	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
2127	ELSEIF ( zw(k) > hv_out ) THEN
2128	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2129	ENDIF
2130	ENDIF
2131	ENDDO
2132	ENDIF
2133	ENDDO
2134	ENDDO
2135
2136	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2137	!
2138	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2139	!-- boundary conditions for topography.
2140	IF ( .NOT. bc_ns_cyc ) THEN
2141	IF ( nys == 0 ) THEN
2142	DO i = 1, nbgp
2143	topo(:,nys-i,:) = topo(:,nys,:)
2144	ENDDO
2145	ENDIF
2146	IF ( nyn == ny ) THEN
2147	DO i = 1, nbgp
2148	topo(:,nyn+i,:) = topo(:,nyn,:)
2149	ENDDO
2150	ENDIF
2151	ENDIF
2152	IF ( .NOT. bc_lr_cyc ) THEN
2153	IF ( nxl == 0 ) THEN
2154	DO i = 1, nbgp
2155	topo(:,:,nxl-i) = topo(:,:,nxl)
2156	ENDDO
2157	ENDIF
2158	IF ( nxr == nx ) THEN
2159	DO i = 1, nbgp
2160	topo(:,:,nxr+i) = topo(:,:,nxr)
2161	ENDDO
2162	ENDIF
2163	ENDIF
2164
2165	CASE ( 'read_from_file' )
2166	!
2167	!-- Note, topography information have been already read.
2168	!-- If required, further process topography, i.e. reference buildings on
2169	!-- top of orography and set temporary 3D topography array, which is
2170	!-- used later to set grid flags. Calling of this rouinte is also
2171	!-- required in case of ASCII input, even though no distinction between
2172	!-- terrain- and building height is made in this case.
2173	CALL process_topography( topo )
2174	!
2175	!-- Filter holes resolved by only one grid-point
2176	CALL filter_topography( topo )
2177	!
2178	!-- Exchange ghost-points, as well as add cyclic or Neumann boundary
2179	!-- conditions.
2180	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2181	!
2182	!-- Set lateral boundary conditions for topography on all ghost layers
2183	IF ( .NOT. bc_ns_cyc ) THEN
2184	IF ( nys == 0 ) THEN
2185	DO i = 1, nbgp
2186	topo(:,nys-i,:) = topo(:,nys,:)
2187	ENDDO
2188	ENDIF
2189	IF ( nyn == ny ) THEN
2190	DO i = 1, nbgp
2191	topo(:,nyn+i,:) = topo(:,nyn,:)
2192	ENDDO
2193	ENDIF
2194	ENDIF
2195
2196	IF ( .NOT. bc_lr_cyc ) THEN
2197	IF ( nxl == 0 ) THEN
2198	DO i = 1, nbgp
2199	topo(:,:,nxl-i) = topo(:,:,nxl)
2200	ENDDO
2201	ENDIF
2202	IF ( nxr == nx ) THEN
2203	DO i = 1, nbgp
2204	topo(:,:,nxr+i) = topo(:,:,nxr)
2205	ENDDO
2206	ENDIF
2207	ENDIF
2208
2209
2210	CASE DEFAULT
2211	!
2212	!-- The DEFAULT case is reached either if the parameter topography
2213	!-- contains a wrong character string or if the user has defined a special
2214	!-- case in the user interface. There, the subroutine user_init_grid
2215	!-- checks which of these two conditions applies.
2216	CALL user_init_grid( topo )
2217	CALL filter_topography( topo )
2218
2219	END SELECT
2220	!
2221	!-- Consistency checks and index array initialization are only required for
2222	!-- non-flat topography.
2223	IF ( TRIM( topography ) /= 'flat' ) THEN
2224	!
2225	!-- In case of non-flat topography, check whether the convention how to
2226	!-- define the topography grid has been set correctly, or whether the default
2227	!-- is applicable. If this is not possible, abort.
2228	IF ( TRIM( topography_grid_convention ) == ' ' ) THEN
2229	IF ( TRIM( topography ) /= 'single_building' .AND. &
2230	TRIM( topography ) /= 'single_street_canyon' .AND. &
2231	TRIM( topography ) /= 'tunnel' .AND. &
2232	TRIM( topography ) /= 'read_from_file') THEN
2233	!-- The default value is not applicable here, because it is only valid
2234	!-- for the four standard cases 'single_building',
2235	!-- 'single_street_canyon', 'tunnel' and 'read_from_file'
2236	!-- defined in init_grid.
2237	WRITE( message_string, * ) &
2238	'The value for "topography_grid_convention" ', &
2239	'is not set. Its default value is & only valid for ', &
2240	'"topography" = ''single_building'', ''tunnel'' ', &
2241	'''single_street_canyon'' & or ''read_from_file''.', &
2242	'& Choose ''cell_edge'' or ''cell_center''.'
2243	CALL message( 'init_grid', 'PA0239', 1, 2, 0, 6, 0 )
2244	ELSE
2245	!-- The default value is applicable here.
2246	!-- Set convention according to topography.
2247	IF ( TRIM( topography ) == 'single_building' .OR. &
2248	TRIM( topography ) == 'single_street_canyon' ) THEN
2249	topography_grid_convention = 'cell_edge'
2250	ELSEIF ( TRIM( topography ) == 'read_from_file' .OR. &
2251	TRIM( topography ) == 'tunnel') THEN
2252	topography_grid_convention = 'cell_center'
2253	ENDIF
2254	ENDIF
2255	ELSEIF ( TRIM( topography_grid_convention ) /= 'cell_edge' .AND. &
2256	TRIM( topography_grid_convention ) /= 'cell_center' ) THEN
2257	WRITE( message_string, * ) &
2258	'The value for "topography_grid_convention" is ', &
2259	'not recognized.& Choose ''cell_edge'' or ''cell_center''.'
2260	CALL message( 'init_grid', 'PA0240', 1, 2, 0, 6, 0 )
2261	ENDIF
2262
2263
2264	IF ( topography_grid_convention == 'cell_edge' ) THEN
2265	!
2266	!-- The array nzb_local as defined using the 'cell_edge' convention
2267	!-- describes the actual total size of topography which is defined at the
2268	!-- cell edges where u=0 on the topography walls in x-direction and v=0
2269	!-- on the topography walls in y-direction. However, PALM uses individual
2270	!-- arrays nzb_u\|v\|w\|s_inner\|outer that are based on nzb_s_inner.
2271	!-- Therefore, the extent of topography in nzb_local is now reduced by
2272	!-- 1dx at the E topography walls and by 1dy at the N topography walls
2273	!-- to form the basis for nzb_s_inner.
2274	!-- Note, the reverse memory access (i-j instead of j-i) is absolutely
2275	!-- required at this point.
2276	DO j = nys+1, nyn+1
2277	DO i = nxl-1, nxr
2278	DO k = nzb, nzt+1
2279	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2280	BTEST( topo(k,j,i+1), 0 ) ) &
2281	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2282	ENDDO
2283	ENDDO
2284	ENDDO
2285	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2286
2287	DO i = nxl, nxr+1
2288	DO j = nys-1, nyn
2289	DO k = nzb, nzt+1
2290	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2291	BTEST( topo(k,j+1,i), 0 ) ) &
2292	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2293	ENDDO
2294	ENDDO
2295	ENDDO
2296	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2297
2298	ENDIF
2299	ENDIF
2300
2301
2302	END SUBROUTINE init_topo
2303
2304	SUBROUTINE set_topo_flags(topo)
2305
2306	USE control_parameters, &
2307	ONLY: bc_lr_cyc, bc_ns_cyc, constant_flux_layer, &
2308	scalar_advec, topography, use_surface_fluxes, use_top_fluxes
2309
2310	USE indices, &
2311	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
2312	nzt, topo_top_ind, wall_flags_0
2313
2314	USE kinds
2315
2316	IMPLICIT NONE
2317
2318	INTEGER(iwp) :: i !< index variable along x
2319	INTEGER(iwp) :: ibit !< integer bit position of topgraphy masking array
2320	INTEGER(iwp) :: j !< index variable along y
2321	INTEGER(iwp) :: k !< index variable along z
2322
2323	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
2324
2325	ALLOCATE( wall_flags_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2326	wall_flags_0 = 0
2327	!
2328	!-- Set-up topography flags. First, set flags only for s, u, v and w-grid.
2329	!-- Further special flags will be set in following loops.
2330	DO i = nxl, nxr
2331	DO j = nys, nyn
2332	DO k = nzb, nzt+1
2333	!
2334	!-- scalar grid
2335	IF ( BTEST( topo(k,j,i), 0 ) ) &
2336	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 0 )
2337	!
2338	!-- u grid
2339	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2340	BTEST( topo(k,j,i-1), 0 ) ) &
2341	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 1 )
2342	!
2343	!-- v grid
2344	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2345	BTEST( topo(k,j-1,i), 0 ) ) &
2346	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 2 )
2347
2348	ENDDO
2349
2350	DO k = nzb, nzt
2351	!
2352	!-- w grid
2353	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2354	BTEST( topo(k+1,j,i), 0 ) ) &
2355	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 3 )
2356	ENDDO
2357	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 3 )
2358
2359	ENDDO
2360	ENDDO
2361
2362	CALL exchange_horiz_int( wall_flags_0, nys, nyn, nxl, nxr, nzt, nbgp )
2363	!
2364	!-- Set outer array for scalars to mask near-surface grid points. Note, on
2365	!-- basis of flag 24 futher flags will be derived which are used to control
2366	!-- production of subgrid TKE production near walls.
2367	DO i = nxl, nxr
2368	DO j = nys, nyn
2369	DO k = nzb, nzt+1
2370	IF ( BTEST( wall_flags_0(k,j-1,i), 0 ) .AND. &
2371	BTEST( wall_flags_0(k,j+1,i), 0 ) .AND. &
2372	BTEST( wall_flags_0(k,j,i-1), 0 ) .AND. &
2373	BTEST( wall_flags_0(k,j,i+1), 0 ) .AND. &
2374	BTEST( wall_flags_0(k,j-1,i-1), 0 ) .AND. &
2375	BTEST( wall_flags_0(k,j+1,i-1), 0 ) .AND. &
2376	BTEST( wall_flags_0(k,j-1,i+1), 0 ) .AND. &
2377	BTEST( wall_flags_0(k,j+1,i+1), 0 ) ) &
2378	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 24 )
2379	ENDDO
2380	ENDDO
2381	ENDDO
2382	!
2383	!-- Set further special flags
2384	DO i = nxl, nxr
2385	DO j = nys, nyn
2386	DO k = nzb, nzt+1
2387	!
2388	!-- scalar grid, former nzb_diff_s_inner.
2389	!-- Note, use this flag also to mask topography in diffusion_u and
2390	!-- diffusion_v along the vertical direction. In case of
2391	!-- use_surface_fluxes, fluxes are calculated via MOST, else, simple
2392	!-- gradient approach is applied. Please note, in case of u- and v-
2393	!-- diffuison, a small error is made at edges (on the east side for u,
2394	!-- at the north side for v), since topography on scalar grid point
2395	!-- is used instead of topography on u/v-grid. As number of topography grid
2396	!-- points on uv-grid is different than s-grid, different number of
2397	!-- surface elements would be required. In order to avoid this,
2398	!-- treat edges (u(k,j,i+1)) simply by a gradient approach, i.e. these
2399	!-- points are not masked within diffusion_u. Tests had shown that the
2400	!-- effect on the flow is negligible.
2401	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2402	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2403	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 8 )
2404	ELSE
2405	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 8 )
2406	ENDIF
2407
2408	ENDDO
2409	!
2410	!-- Special flag to control vertical diffusion at model top - former
2411	!-- nzt_diff
2412	wall_flags_0(:,j,i) = IBSET( wall_flags_0(:,j,i), 9 )
2413	IF ( use_top_fluxes ) &
2414	wall_flags_0(nzt+1,j,i) = IBCLR( wall_flags_0(nzt+1,j,i), 9 )
2415
2416
2417	DO k = nzb+1, nzt
2418	!
2419	!-- Special flag on u grid, former nzb_u_inner + 1, required
2420	!-- for disturb_field and initialization. Do not disturb directly at
2421	!-- topography, as well as initialize u with zero one grid point outside
2422	!-- of topography.
2423	IF ( BTEST( wall_flags_0(k-1,j,i), 1 ) .AND. &
2424	BTEST( wall_flags_0(k,j,i), 1 ) .AND. &
2425	BTEST( wall_flags_0(k+1,j,i), 1 ) ) &
2426	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 20 )
2427	!
2428	!-- Special flag on v grid, former nzb_v_inner + 1, required
2429	!-- for disturb_field and initialization. Do not disturb directly at
2430	!-- topography, as well as initialize v with zero one grid point outside
2431	!-- of topography.
2432	IF ( BTEST( wall_flags_0(k-1,j,i), 2 ) .AND. &
2433	BTEST( wall_flags_0(k,j,i), 2 ) .AND. &
2434	BTEST( wall_flags_0(k+1,j,i), 2 ) ) &
2435	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 21 )
2436	!
2437	!-- Special flag on scalar grid, former nzb_s_inner+1. Used for
2438	!-- lpm_sgs_tke
2439	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2440	BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2441	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2442	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 25 )
2443	!
2444	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2445	!-- in production_e
2446	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2447	IF ( BTEST( wall_flags_0(k,j,i), 24 ) .AND. &
2448	BTEST( wall_flags_0(k-1,j,i), 24 ) .AND. &
2449	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2450	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 29 )
2451	ELSE
2452	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2453	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 29 )
2454	ENDIF
2455	!
2456	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2457	!-- in production_e
2458	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2459	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2460	BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2461	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2462	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 30 )
2463	ELSE
2464	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2465	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 30 )
2466	ENDIF
2467	ENDDO
2468	!
2469	!-- Flags indicating downward facing walls
2470	DO k = nzb+1, nzt
2471	!
2472	!-- Scalar grid
2473	IF ( BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2474	.NOT. BTEST( wall_flags_0(k,j,i), 0 ) ) &
2475	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 13 )
2476	!
2477	!-- Downward facing wall on u grid
2478	IF ( BTEST( wall_flags_0(k-1,j,i), 1 ) .AND. &
2479	.NOT. BTEST( wall_flags_0(k,j,i), 1 ) ) &
2480	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 15 )
2481	!
2482	!-- Downward facing wall on v grid
2483	IF ( BTEST( wall_flags_0(k-1,j,i), 2 ) .AND. &
2484	.NOT. BTEST( wall_flags_0(k,j,i), 2 ) ) &
2485	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 17 )
2486	!
2487	!-- Downward facing wall on w grid
2488	IF ( BTEST( wall_flags_0(k-1,j,i), 3 ) .AND. &
2489	.NOT. BTEST( wall_flags_0(k,j,i), 3 ) ) &
2490	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 19 )
2491	ENDDO
2492	!
2493	!-- Flags indicating upward facing walls
2494	DO k = nzb, nzt
2495	!
2496	!-- Upward facing wall on scalar grid
2497	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2498	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2499	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 12 )
2500	!
2501	!-- Upward facing wall on u grid
2502	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 1 ) .AND. &
2503	BTEST( wall_flags_0(k+1,j,i), 1 ) ) &
2504	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 14 )
2505
2506	!
2507	!-- Upward facing wall on v grid
2508	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 2 ) .AND. &
2509	BTEST( wall_flags_0(k+1,j,i), 2 ) ) &
2510	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 16 )
2511
2512	!
2513	!-- Upward facing wall on w grid
2514	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 3 ) .AND. &
2515	BTEST( wall_flags_0(k+1,j,i), 3 ) ) &
2516	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 18 )
2517	!
2518	!-- Special flag on scalar grid, former nzb_s_inner
2519	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .OR. &
2520	BTEST( wall_flags_0(k,j,i), 12 ) .OR. &
2521	BTEST( wall_flags_0(k,j,i), 13 ) ) &
2522	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 22 )
2523	!
2524	!-- Special flag on scalar grid, nzb_diff_s_inner - 1, required for
2525	!-- flow_statistics
2526	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2527	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2528	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2529	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 23 )
2530	ELSE
2531	IF ( BTEST( wall_flags_0(k,j,i), 22 ) ) &
2532	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 23 )
2533	ENDIF
2534
2535
2536	ENDDO
2537	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 22 )
2538	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 23 )
2539	!
2540	!-- Set flags indicating that topography is close by in horizontal
2541	!-- direction, i.e. flags that infold the topography. These will be used
2542	!-- to set advection flags for passive scalars, where due to large
2543	!-- gradients near buildings stationary numerical oscillations can produce
2544	!-- unrealistically high concentrations. This is only necessary if
2545	!-- WS-scheme is applied for scalar advection. Note, these flags will be
2546	!-- only used for passive scalars such as chemical species or aerosols.
2547	IF ( scalar_advec == 'ws-scheme' ) THEN
2548	DO k = nzb, nzt
2549	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. ( &
2550	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-1), 0 ) ) .OR.&
2551	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-2), 0 ) ) .OR.&
2552	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-3), 0 ) ) .OR.&
2553	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+1), 0 ) ) .OR.&
2554	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+2), 0 ) ) .OR.&
2555	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+3), 0 ) ) .OR.&
2556	ANY( .NOT. BTEST( wall_flags_0(k,j-1,i-3:i+3), 0 ) ) .OR.&
2557	ANY( .NOT. BTEST( wall_flags_0(k,j-2,i-3:i+3), 0 ) ) .OR.&
2558	ANY( .NOT. BTEST( wall_flags_0(k,j-3,i-3:i+3), 0 ) ) .OR.&
2559	ANY( .NOT. BTEST( wall_flags_0(k,j+1,i-3:i+3), 0 ) ) .OR.&
2560	ANY( .NOT. BTEST( wall_flags_0(k,j+2,i-3:i+3), 0 ) ) .OR.&
2561	ANY( .NOT. BTEST( wall_flags_0(k,j+3,i-3:i+3), 0 ) ) &
2562	) ) &
2563	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 31 )
2564
2565	ENDDO
2566	ENDIF
2567	ENDDO
2568	ENDDO
2569	!
2570	!-- Finally, set identification flags indicating natural terrain or buildings.
2571	!-- Natural terrain grid points. Information on the type of the surface is
2572	!-- stored in bit 1 of 3D Integer array topo. However, this bit is only set
2573	!-- when topography is read from file. In order to run the land-surface model
2574	!-- also without topography information, set bit 1 explicitely in this case.
2575	!--
2576	!-- Natural terrain grid points
2577	!-- If no topography is initialized, the land-surface is at k = nzb.
2578	IF ( TRIM( topography ) /= 'read_from_file' ) THEN
2579	wall_flags_0(nzb,:,:) = IBSET( wall_flags_0(nzb,:,:), 5 )
2580	ELSE
2581	DO i = nxl, nxr
2582	DO j = nys, nyn
2583	DO k = nzb, nzt+1
2584	!
2585	!-- Natural terrain grid point
2586	IF ( BTEST( topo(k,j,i), 1 ) ) &
2587	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 5 )
2588	ENDDO
2589	ENDDO
2590	ENDDO
2591	ENDIF
2592	!
2593	!-- Building grid points.
2594	DO i = nxl, nxr
2595	DO j = nys, nyn
2596	DO k = nzb, nzt+1
2597	IF ( BTEST( topo(k,j,i), 2 ) ) &
2598	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 6 )
2599	ENDDO
2600	ENDDO
2601	ENDDO
2602	!
2603	!-- Exchange ghost points for wall flags
2604	CALL exchange_horiz_int( wall_flags_0, nys, nyn, nxl, nxr, nzt, nbgp )
2605	!
2606	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2607	!-- boundary conditions for topography.
2608	IF ( .NOT. bc_ns_cyc ) THEN
2609	IF ( nys == 0 ) THEN
2610	DO i = 1, nbgp
2611	wall_flags_0(:,nys-i,:) = wall_flags_0(:,nys,:)
2612	ENDDO
2613	ENDIF
2614	IF ( nyn == ny ) THEN
2615	DO i = 1, nbgp
2616	wall_flags_0(:,nyn+i,:) = wall_flags_0(:,nyn,:)
2617	ENDDO
2618	ENDIF
2619	ENDIF
2620	IF ( .NOT. bc_lr_cyc ) THEN
2621	IF ( nxl == 0 ) THEN
2622	DO i = 1, nbgp
2623	wall_flags_0(:,:,nxl-i) = wall_flags_0(:,:,nxl)
2624	ENDDO
2625	ENDIF
2626	IF ( nxr == nx ) THEN
2627	DO i = 1, nbgp
2628	wall_flags_0(:,:,nxr+i) = wall_flags_0(:,:,nxr)
2629	ENDDO
2630	ENDIF
2631	ENDIF
2632	!
2633	!-- Pre-calculate topography top indices (former get_topography_top_index
2634	!-- function)
2635	ALLOCATE( topo_top_ind(nysg:nyng,nxlg:nxrg,0:4) )
2636	!
2637	!-- Uppermost topography index on scalar grid
2638	ibit = 12
2639	topo_top_ind(:,:,0) = MAXLOC( &
2640	MERGE( 1, 0, &
2641	BTEST( wall_flags_0(:,:,:), ibit ) &
2642	), DIM = 1 &
2643	) - 1
2644	!
2645	!-- Uppermost topography index on u grid
2646	ibit = 14
2647	topo_top_ind(:,:,1) = MAXLOC( &
2648	MERGE( 1, 0, &
2649	BTEST( wall_flags_0(:,:,:), ibit ) &
2650	), DIM = 1 &
2651	) - 1
2652	!
2653	!-- Uppermost topography index on v grid
2654	ibit = 16
2655	topo_top_ind(:,:,2) = MAXLOC( &
2656	MERGE( 1, 0, &
2657	BTEST( wall_flags_0(:,:,:), ibit ) &
2658	), DIM = 1 &
2659	) - 1
2660	!
2661	!-- Uppermost topography index on w grid
2662	ibit = 18
2663	topo_top_ind(:,:,3) = MAXLOC( &
2664	MERGE( 1, 0, &
2665	BTEST( wall_flags_0(:,:,:), ibit ) &
2666	), DIM = 1 &
2667	) - 1
2668	!
2669	!-- Uppermost topography index on scalar outer grid
2670	ibit = 24
2671	topo_top_ind(:,:,4) = MAXLOC( &
2672	MERGE( 1, 0, &
2673	BTEST( wall_flags_0(:,:,:), ibit ) &
2674	), DIM = 1 &
2675	) - 1
2676
2677	END SUBROUTINE set_topo_flags
2678
2679
2680

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