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source: palm/trunk/SOURCE/init_grid.f90 @ 4242

Last change on this file since 4242 was 4189, checked in by suehring, 5 years ago
init_grid: Add check for proper setting of namelist parameter topography; Set bit flag to indicate land surfaces in case no topography is provided
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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 4189 2019-08-26 16:19:38Z suehring $
27	! - Add check for proper setting of namelist parameter topography
28	! - Set flag to indicate land surfaces in case no topography is provided
29	!
30	! 4182 2019-08-22 15:20:23Z scharf
31	! Corrected "Former revisions" section
32	!
33	! 4168 2019-08-16 13:50:17Z suehring
34	! Pre-calculate topography top index and store it on an array (replaces former
35	! functions get_topography_top_index)
36	!
37	! 4159 2019-08-15 13:31:35Z suehring
38	! Revision of topography processing. This was not consistent between 2D and 3D
39	! buildings.
40	!
41	! 4144 2019-08-06 09:11:47Z raasch
42	! relational operators .EQ., .NE., etc. replaced by ==, /=, etc.
43	!
44	! 4115 2019-07-24 12:50:49Z suehring
45	! Bugfix in setting near-surface flag 24, inidicating wall-bounded grid points
46	!
47	! 4110 2019-07-22 17:05:21Z suehring
48	! - Separate initialization of advection flags for momentum and scalars.
49	! - Change subroutine interface for ws_init_flags_scalar to pass boundary flags
50	!
51	! 4109 2019-07-22 17:00:34Z suehring
52	! Fix bad commit
53	!
54	! 3926 2019-04-23 12:56:42Z suehring
55	! Minor bugfix in building mapping when all building IDs in the model domain
56	! are missing
57	!
58	! 3857 2019-04-03 13:00:16Z knoop
59	! In projection of non-building 3D objects onto numerical grid remove
60	! dependency on building_type
61	!
62	! 3763 2019-02-25 17:33:49Z suehring
63	! Replace work-around for ghost point exchange of 1-byte arrays with specific
64	! routine as already done in other routines
65	!
66	! 3761 2019-02-25 15:31:42Z raasch
67	! unused variables removed
68	!
69	! 3661 2019-01-08 18:22:50Z suehring
70	! Remove setting of nzb_max to nzt at non-cyclic boundary PEs, instead,
71	! order degradation of advection scheme is handeled directly in advec_ws
72	!
73	! 3655 2019-01-07 16:51:22Z knoop
74	! Comment added
75	!
76	! Revision 1.1 1997/08/11 06:17:45 raasch
77	! Initial revision (Testversion)
78	!
79	!
80	! Description:
81	! -----------------------------------------------------------------------------!
82	!> Creating grid depending constants
83	!> @todo: Rearrange topo flag list
84	!> @todo: reference 3D buildings on top of orography is not tested and may need
85	!> further improvement for steep slopes
86	!> @todo: Use more advanced setting of building type at filled holes
87	!------------------------------------------------------------------------------!
88	SUBROUTINE init_grid
89
90	USE advec_ws, &
91	ONLY: ws_init_flags_momentum, ws_init_flags_scalar
92
93	USE arrays_3d, &
94	ONLY: dd2zu, ddzu, ddzu_pres, ddzw, dzu, dzw, x, xu, y, yv, zu, zw
95
96	USE control_parameters, &
97	ONLY: bc_lr_cyc, bc_ns_cyc, &
98	bc_dirichlet_l, &
99	bc_dirichlet_n, &
100	bc_dirichlet_r, &
101	bc_dirichlet_s, &
102	bc_radiation_l, &
103	bc_radiation_n, &
104	bc_radiation_r, &
105	bc_radiation_s, &
106	constant_flux_layer, dz, dz_max, dz_stretch_factor, &
107	dz_stretch_factor_array, dz_stretch_level, dz_stretch_level_end,&
108	dz_stretch_level_end_index, dz_stretch_level_start_index, &
109	dz_stretch_level_start, ibc_uv_b, message_string, &
110	momentum_advec, number_stretch_level_end, &
111	number_stretch_level_start, ocean_mode, psolver, scalar_advec, &
112	topography, use_surface_fluxes
113
114	USE grid_variables, &
115	ONLY: ddx, ddx2, ddy, ddy2, dx, dx2, dy, dy2, zu_s_inner, zw_w_inner
116
117	USE indices, &
118	ONLY: advc_flags_m, &
119	advc_flags_s, &
120	nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
121	nzb, nzb_diff, nzb_diff_s_inner, nzb_diff_s_outer, &
122	nzb_max, nzb_s_inner, nzb_s_outer, nzb_u_inner, &
123	nzb_u_outer, nzb_v_inner, nzb_v_outer, nzb_w_inner, &
124	nzb_w_outer, nzt, topo_top_ind, topo_min_level
125
126	USE kinds
127
128	USE pegrid
129
130	USE poismg_noopt_mod
131
132	USE surface_mod, &
133	ONLY: init_bc
134
135	USE vertical_nesting_mod, &
136	ONLY: vnested, vnest_init_grid
137
138	IMPLICIT NONE
139
140	INTEGER(iwp) :: i !< index variable along x
141	INTEGER(iwp) :: j !< index variable along y
142	INTEGER(iwp) :: k !< index variable along z
143	INTEGER(iwp) :: k_top !< topography top index on local PE
144	INTEGER(iwp) :: n !< loop variable for stretching
145	INTEGER(iwp) :: number_dz !< number of user-specified dz values
146	INTEGER(iwp) :: nzb_local_max !< vertical grid index of maximum topography height
147	INTEGER(iwp) :: nzb_local_min !< vertical grid index of minimum topography height
148
149	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
150	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_tmp !< dummy to calculate topography indices on u- and v-grid
151
152	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
153
154	REAL(wp) :: dz_level_end !< distance between calculated height level for u/v-grid and user-specified end level for stretching
155	REAL(wp) :: dz_stretched !< stretched vertical grid spacing
156
157	REAL(wp), DIMENSION(:), ALLOCATABLE :: min_dz_stretch_level_end !< Array that contains all minimum heights where the stretching can end
158
159
160	!
161	!-- Calculation of horizontal array bounds including ghost layers
162	nxlg = nxl - nbgp
163	nxrg = nxr + nbgp
164	nysg = nys - nbgp
165	nyng = nyn + nbgp
166
167	!
168	!-- Allocate grid arrays
169	ALLOCATE( x(0:nx), xu(0:nx) )
170	DO i = 0, nx
171	xu(i) = i * dx
172	x(i) = i * dx + 0.5_wp * dx
173	ENDDO
174
175	ALLOCATE( y(0:ny), yv(0:ny) )
176	DO j = 0, ny
177	yv(j) = j * dy
178	y(j) = j * dy + 0.5_wp * dy
179	ENDDO
180
181	!
182	!-- Allocate grid arrays
183	ALLOCATE( ddzu(1:nzt+1), ddzw(1:nzt+1), dd2zu(1:nzt), dzu(1:nzt+1), &
184	dzw(1:nzt+1), zu(nzb:nzt+1), zw(nzb:nzt+1) )
185
186	!
187	!-- Compute height of u-levels from constant grid length and dz stretch factors
188	IF ( dz(1) == -1.0_wp ) THEN
189	message_string = 'missing dz'
190	CALL message( 'init_grid', 'PA0200', 1, 2, 0, 6, 0 )
191	ELSEIF ( dz(1) <= 0.0_wp ) THEN
192	WRITE( message_string, * ) 'dz=',dz(1),' <= 0.0'
193	CALL message( 'init_grid', 'PA0201', 1, 2, 0, 6, 0 )
194	ENDIF
195
196	!
197	!-- Initialize dz_stretch_level_start with the value of dz_stretch_level
198	!-- if it was set by the user
199	IF ( dz_stretch_level /= -9999999.9_wp ) THEN
200	dz_stretch_level_start(1) = dz_stretch_level
201	ENDIF
202
203	!
204	!-- Determine number of dz values and stretching levels specified by the
205	!-- user to allow right controlling of the stretching mechanism and to
206	!-- perform error checks. The additional requirement that dz /= dz_max
207	!-- for counting number of user-specified dz values is necessary. Otherwise
208	!-- restarts would abort if the old stretching mechanism with dz_stretch_level
209	!-- is used (Attention: The user is not allowed to specify a dz value equal
210	!-- to the default of dz_max = 999.0).
211	number_dz = COUNT( dz /= -1.0_wp .AND. dz /= dz_max)
212	number_stretch_level_start = COUNT( dz_stretch_level_start /= &
213	-9999999.9_wp )
214	number_stretch_level_end = COUNT( dz_stretch_level_end /= &
215	9999999.9_wp )
216
217	!
218	!-- The number of specified end levels +1 has to be the same than the number
219	!-- of specified dz values
220	IF ( number_dz /= number_stretch_level_end + 1 ) THEN
221	WRITE( message_string, * ) 'The number of values for dz = ', &
222	number_dz, 'has to be the same than& ', &
223	'the number of values for ', &
224	'dz_stretch_level_end + 1 = ', &
225	number_stretch_level_end+1
226	CALL message( 'init_grid', 'PA0156', 1, 2, 0, 6, 0 )
227	ENDIF
228
229	!
230	!-- The number of specified start levels has to be the same or one less than
231	!-- the number of specified dz values
232	IF ( number_dz /= number_stretch_level_start + 1 .AND. &
233	number_dz /= number_stretch_level_start ) THEN
234	WRITE( message_string, * ) 'The number of values for dz = ', &
235	number_dz, 'has to be the same or one ', &
236	'more than& the number of values for ', &
237	'dz_stretch_level_start = ', &
238	number_stretch_level_start
239	CALL message( 'init_grid', 'PA0211', 1, 2, 0, 6, 0 )
240	ENDIF
241
242	!-- The number of specified start levels has to be the same or one more than
243	!-- the number of specified end levels
244	IF ( number_stretch_level_start /= number_stretch_level_end + 1 .AND. &
245	number_stretch_level_start /= number_stretch_level_end ) THEN
246	WRITE( message_string, * ) 'The number of values for ', &
247	'dz_stretch_level_start = ', &
248	dz_stretch_level_start, 'has to be the ',&
249	'same or one more than& the number of ', &
250	'values for dz_stretch_level_end = ', &
251	number_stretch_level_end
252	CALL message( 'init_grid', 'PA0216', 1, 2, 0, 6, 0 )
253	ENDIF
254
255	!
256	!-- Initialize dz for the free atmosphere with the value of dz_max
257	IF ( dz(number_stretch_level_start+1) == -1.0_wp .AND. &
258	number_stretch_level_start /= 0 ) THEN
259	dz(number_stretch_level_start+1) = dz_max
260	ENDIF
261
262	!
263	!-- Initialize the stretching factor if (infinitely) stretching in the free
264	!-- atmosphere is desired (dz_stretch_level_end was not specified for the
265	!-- free atmosphere)
266	IF ( number_stretch_level_start == number_stretch_level_end + 1 ) THEN
267	dz_stretch_factor_array(number_stretch_level_start) = &
268	dz_stretch_factor
269	ENDIF
270
271	!
272	!-- Allocation of arrays for stretching
273	ALLOCATE( min_dz_stretch_level_end(number_stretch_level_start) )
274
275	!
276	!-- Define the vertical grid levels
277	IF ( .NOT. ocean_mode ) THEN
278
279	!
280	!-- The stretching region has to be large enough to allow for a smooth
281	!-- transition between two different grid spacings
282	DO n = 1, number_stretch_level_start
283	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) + &
284	4 * MAX( dz(n),dz(n+1) )
285	ENDDO
286
287	IF ( ANY( min_dz_stretch_level_end(1:number_stretch_level_start) > &
288	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
289	message_string= 'Eeach dz_stretch_level_end has to be larger ' // &
290	'than its corresponding value for &' // &
291	'dz_stretch_level_start + 4*MAX(dz(n),dz(n+1)) '//&
292	'to allow for smooth grid stretching'
293	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
294	ENDIF
295
296	!
297	!-- Stretching must not be applied within the prandtl_layer
298	!-- (first two grid points). For the default case dz_stretch_level_start
299	!-- is negative. Therefore the absolut value is checked here.
300	IF ( ANY( ABS( dz_stretch_level_start ) < dz(1) * 1.5_wp ) ) THEN
301	WRITE( message_string, * ) 'Eeach dz_stretch_level_start has to be ',&
302	'larger than ', dz(1) * 1.5
303	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
304	ENDIF
305
306	!
307	!-- The stretching has to start and end on a grid level. Therefore
308	!-- user-specified values have to ''interpolate'' to the next lowest level
309	IF ( number_stretch_level_start /= 0 ) THEN
310	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) - &
311	dz(1)/2.0) / dz(1) ) &
312	* dz(1) + dz(1)/2.0
313	ENDIF
314
315	IF ( number_stretch_level_start > 1 ) THEN
316	DO n = 2, number_stretch_level_start
317	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
318	dz(n) ) * dz(n)
319	ENDDO
320	ENDIF
321
322	IF ( number_stretch_level_end /= 0 ) THEN
323	DO n = 1, number_stretch_level_end
324	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
325	dz(n+1) ) * dz(n+1)
326	ENDDO
327	ENDIF
328
329	!
330	!-- Determine stretching factor if necessary
331	IF ( number_stretch_level_end >= 1 ) THEN
332	CALL calculate_stretching_factor( number_stretch_level_end )
333	ENDIF
334
335	!
336	!-- Grid for atmosphere with surface at z=0 (k=0, w-grid).
337	!-- First compute the u- and v-levels. In case of dirichlet bc for u and v
338	!-- the first u/v- and w-level (k=0) are defined at same height (z=0).
339	!-- The second u-level (k=1) corresponds to the top of the
340	!-- Prandtl-layer.
341	IF ( ibc_uv_b == 0 .OR. ibc_uv_b == 2 ) THEN
342	zu(0) = 0.0_wp
343	ELSE
344	zu(0) = - dz(1) * 0.5_wp
345	ENDIF
346
347	zu(1) = dz(1) * 0.5_wp
348
349	!
350	!-- Determine u and v height levels considering the possibility of grid
351	!-- stretching in several heights.
352	n = 1
353	dz_stretch_level_start_index = nzt+1
354	dz_stretch_level_end_index = nzt+1
355	dz_stretched = dz(1)
356
357	!-- The default value of dz_stretch_level_start is negative, thus the first
358	!-- condition is always true. Hence, the second condition is necessary.
359	DO k = 2, nzt+1
360	IF ( dz_stretch_level_start(n) <= zu(k-1) .AND. &
361	dz_stretch_level_start(n) /= -9999999.9_wp ) THEN
362	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
363
364	IF ( dz(n) > dz(n+1) ) THEN
365	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
366	ELSE
367	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
368	ENDIF
369
370	IF ( dz_stretch_level_start_index(n) == nzt+1 ) &
371	dz_stretch_level_start_index(n) = k-1
372
373	ENDIF
374
375	zu(k) = zu(k-1) + dz_stretched
376
377	!
378	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
379	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
380
381	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
382	zu(k) = dz_stretch_level_end(n)
383	dz_stretched = dz(n+1)
384	dz_stretch_level_end_index(n) = k
385	n = n + 1
386	ENDIF
387	ENDDO
388
389	!
390	!-- Compute the w-levels. They are always staggered half-way between the
391	!-- corresponding u-levels. In case of dirichlet bc for u and v at the
392	!-- ground the first u- and w-level (k=0) are defined at same height (z=0).
393	!-- The top w-level is extrapolated linearly.
394	zw(0) = 0.0_wp
395	DO k = 1, nzt
396	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
397	ENDDO
398	zw(nzt+1) = zw(nzt) + 2.0_wp * ( zu(nzt+1) - zw(nzt) )
399
400	ELSE
401
402	!
403	!-- The stretching region has to be large enough to allow for a smooth
404	!-- transition between two different grid spacings
405	DO n = 1, number_stretch_level_start
406	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) - &
407	4 * MAX( dz(n),dz(n+1) )
408	ENDDO
409
410	IF ( ANY( min_dz_stretch_level_end (1:number_stretch_level_start) < &
411	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
412	message_string= 'Eeach dz_stretch_level_end has to be less ' // &
413	'than its corresponding value for &' // &
414	'dz_stretch_level_start - 4*MAX(dz(n),dz(n+1)) '//&
415	'to allow for smooth grid stretching'
416	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
417	ENDIF
418
419	!
420	!-- Stretching must not be applied close to the surface (last two grid
421	!-- points). For the default case dz_stretch_level_start is negative.
422	IF ( ANY( dz_stretch_level_start > - dz(1) * 1.5_wp ) ) THEN
423	WRITE( message_string, * ) 'Eeach dz_stretch_level_start has to be ',&
424	'less than ', dz(1) * 1.5
425	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
426	ENDIF
427
428	!
429	!-- The stretching has to start and end on a grid level. Therefore
430	!-- user-specified values have to ''interpolate'' to the next highest level
431	IF ( number_stretch_level_start /= 0 ) THEN
432	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) + &
433	dz(1)/2.0) / dz(1) ) &
434	* dz(1) - dz(1)/2.0
435	ENDIF
436
437	IF ( number_stretch_level_start > 1 ) THEN
438	DO n = 2, number_stretch_level_start
439	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
440	dz(n) ) * dz(n)
441	ENDDO
442	ENDIF
443
444	IF ( number_stretch_level_end /= 0 ) THEN
445	DO n = 1, number_stretch_level_end
446	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
447	dz(n+1) ) * dz(n+1)
448	ENDDO
449	ENDIF
450
451	!
452	!-- Determine stretching factor if necessary
453	IF ( number_stretch_level_end >= 1 ) THEN
454	CALL calculate_stretching_factor( number_stretch_level_end )
455	ENDIF
456
457	!
458	!-- Grid for ocean with free water surface is at k=nzt (w-grid).
459	!-- In case of neumann bc at the ground the first first u-level (k=0) lies
460	!-- below the first w-level (k=0). In case of dirichlet bc the first u- and
461	!-- w-level are defined at same height, but staggered from the second level.
462	!-- The second u-level (k=1) corresponds to the top of the Prandtl-layer.
463	!-- z values are negative starting from z=0 (surface)
464	zu(nzt+1) = dz(1) * 0.5_wp
465	zu(nzt) = - dz(1) * 0.5_wp
466
467	!
468	!-- Determine u and v height levels considering the possibility of grid
469	!-- stretching in several heights.
470	n = 1
471	dz_stretch_level_start_index = 0
472	dz_stretch_level_end_index = 0
473	dz_stretched = dz(1)
474
475	DO k = nzt-1, 0, -1
476
477	IF ( dz_stretch_level_start(n) >= zu(k+1) ) THEN
478	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
479
480	IF ( dz(n) > dz(n+1) ) THEN
481	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
482	ELSE
483	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
484	ENDIF
485
486	IF ( dz_stretch_level_start_index(n) == 0 ) &
487	dz_stretch_level_start_index(n) = k+1
488
489	ENDIF
490
491	zu(k) = zu(k+1) - dz_stretched
492
493	!
494	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
495	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
496
497	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
498	zu(k) = dz_stretch_level_end(n)
499	dz_stretched = dz(n+1)
500	dz_stretch_level_end_index(n) = k
501	n = n + 1
502	ENDIF
503	ENDDO
504
505	!
506	!-- Compute the w-levels. They are always staggered half-way between the
507	!-- corresponding u-levels, except in case of dirichlet bc for u and v
508	!-- at the ground. In this case the first u- and w-level are defined at
509	!-- same height. The top w-level (nzt+1) is not used but set for
510	!-- consistency, since w and all scalar variables are defined up tp nzt+1.
511	zw(nzt+1) = dz(1)
512	zw(nzt) = 0.0_wp
513	DO k = 0, nzt
514	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
515	ENDDO
516
517	!
518	!-- In case of dirichlet bc for u and v the first u- and w-level are defined
519	!-- at same height.
520	IF ( ibc_uv_b == 0 ) THEN
521	zu(0) = zw(0)
522	ENDIF
523
524	ENDIF
525
526	!
527	!-- Compute grid lengths.
528	DO k = 1, nzt+1
529	dzu(k) = zu(k) - zu(k-1)
530	ddzu(k) = 1.0_wp / dzu(k)
531	dzw(k) = zw(k) - zw(k-1)
532	ddzw(k) = 1.0_wp / dzw(k)
533	ENDDO
534
535	DO k = 1, nzt
536	dd2zu(k) = 1.0_wp / ( dzu(k) + dzu(k+1) )
537	ENDDO
538
539	!
540	!-- The FFT- SOR-pressure solvers assume grid spacings of a staggered grid
541	!-- everywhere. For the actual grid, the grid spacing at the lowest level
542	!-- is only dz/2, but should be dz. Therefore, an additional array
543	!-- containing with appropriate grid information is created for these
544	!-- solvers.
545	IF ( psolver(1:9) /= 'multigrid' ) THEN
546	ALLOCATE( ddzu_pres(1:nzt+1) )
547	ddzu_pres = ddzu
548	ddzu_pres(1) = ddzu_pres(2) ! change for lowest level
549	ENDIF
550
551	!
552	!-- Compute the reciprocal values of the horizontal grid lengths.
553	ddx = 1.0_wp / dx
554	ddy = 1.0_wp / dy
555	dx2 = dx * dx
556	dy2 = dy * dy
557	ddx2 = 1.0_wp / dx2
558	ddy2 = 1.0_wp / dy2
559
560	!
561	!-- Allocate 3D array to set topography
562	ALLOCATE( topo(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
563	topo = 0
564	!
565	!-- Initialize topography by generic topography or read from topography from file.
566	CALL init_topo( topo )
567	!
568	!-- Set flags to mask topography on the grid.
569	CALL set_topo_flags( topo )
570	!
571	!-- Calculate wall flag arrays for the multigrid method.
572	!-- Please note, wall flags are only applied in the non-optimized version.
573	IF ( psolver == 'multigrid_noopt' ) CALL poismg_noopt_init
574
575	!
576	!-- Init flags for ws-scheme to degrade order of the numerics near walls, i.e.
577	!-- to decrease the numerical stencil appropriately. The order of the scheme
578	!-- is degraded near solid walls as well as near non-cyclic inflow and outflow
579	!-- boundaries. Do this separately for momentum and scalars.
580	IF ( momentum_advec == 'ws-scheme' ) THEN
581	ALLOCATE( advc_flags_m(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
582	CALL ws_init_flags_momentum
583	ENDIF
584	IF ( scalar_advec == 'ws-scheme' ) THEN
585	ALLOCATE( advc_flags_s(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
586	advc_flags_s = 0
587
588	CALL ws_init_flags_scalar( bc_dirichlet_l .OR. bc_radiation_l, &
589	bc_dirichlet_n .OR. bc_radiation_n, &
590	bc_dirichlet_r .OR. bc_radiation_r, &
591	bc_dirichlet_s .OR. bc_radiation_s, &
592	advc_flags_s )
593	ENDIF
594
595	!
596	!-- Determine the maximum level of topography. It is used for
597	!-- steering the degradation of order of the applied advection scheme,
598	!-- as well in the lpm.
599	k_top = 0
600	DO i = nxl, nxr
601	DO j = nys, nyn
602	DO k = nzb, nzt + 1
603	k_top = MAX( k_top, MERGE( k, 0, .NOT. BTEST( topo(k,j,i), 0 ) ) )
604	ENDDO
605	ENDDO
606	ENDDO
607	#if defined( __parallel )
608	CALL MPI_ALLREDUCE( k_top + 1, nzb_max, 1, MPI_INTEGER, & !is +1 really necessary here?
609	MPI_MAX, comm2d, ierr )
610	#else
611	nzb_max = k_top + 1
612	#endif
613	!
614	!-- If topography extents up to the model top, limit nzb_max to nzt.
615	nzb_max = MIN( nzb_max, nzt )
616	!
617	!-- Determine minimum index of topography. Usually, this will be nzb. In case
618	!-- there is elevated topography, however, the lowest topography will be higher.
619	!-- This index is e.g. used to calculate mean first-grid point atmosphere
620	!-- temperature, surface pressure and density, etc. .
621	topo_min_level = 0
622	#if defined( __parallel )
623	CALL MPI_ALLREDUCE( MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
624	topo_min_level, 1, MPI_INTEGER, MPI_MIN, comm2d, ierr )
625	#else
626	topo_min_level = MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
627	#endif
628	!
629	!-- Initialize boundary conditions via surface type
630	CALL init_bc
631
632	!
633	!-- Allocate and set topography height arrays required for data output
634	IF ( TRIM( topography ) /= 'flat' ) THEN
635	!
636	!-- Allocate and set the arrays containing the topography height
637	IF ( nxr == nx .AND. nyn /= ny ) THEN
638	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn), &
639	zw_w_inner(nxl:nxr+1,nys:nyn) )
640	ELSEIF ( nxr /= nx .AND. nyn == ny ) THEN
641	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn+1), &
642	zw_w_inner(nxl:nxr,nys:nyn+1) )
643	ELSEIF ( nxr == nx .AND. nyn == ny ) THEN
644	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn+1), &
645	zw_w_inner(nxl:nxr+1,nys:nyn+1) )
646	ELSE
647	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn), &
648	zw_w_inner(nxl:nxr,nys:nyn) )
649	ENDIF
650
651	zu_s_inner = 0.0_wp
652	zw_w_inner = 0.0_wp
653	!
654	!-- Determine local topography height on scalar and w-grid. Note, setting
655	!-- lateral boundary values is not necessary, realized via wall_flags_0
656	!-- array. Further, please note that loop bounds are different from
657	!-- nxl to nxr and nys to nyn on south and right model boundary, hence,
658	!-- use intrinsic lbound and ubound functions to infer array bounds.
659	DO i = LBOUND(zu_s_inner, 1), UBOUND(zu_s_inner, 1)
660	DO j = LBOUND(zu_s_inner, 2), UBOUND(zu_s_inner, 2)
661	!
662	!-- Topography height on scalar grid. Therefore, determine index of
663	!-- upward-facing surface element on scalar grid.
664	zu_s_inner(i,j) = zu(topo_top_ind(j,i,0))
665	!
666	!-- Topography height on w grid. Therefore, determine index of
667	!-- upward-facing surface element on w grid.
668	zw_w_inner(i,j) = zw(topo_top_ind(j,i,3))
669	ENDDO
670	ENDDO
671	ENDIF
672
673	!
674	!-- In the following, calculate 2D index arrays. Note, these will be removed
675	!-- soon.
676	!-- Allocate outer and inner index arrays for topography and set
677	!-- defaults.
678	ALLOCATE( nzb_s_inner(nysg:nyng,nxlg:nxrg), &
679	nzb_s_outer(nysg:nyng,nxlg:nxrg), &
680	nzb_u_inner(nysg:nyng,nxlg:nxrg), &
681	nzb_u_outer(nysg:nyng,nxlg:nxrg), &
682	nzb_v_inner(nysg:nyng,nxlg:nxrg), &
683	nzb_v_outer(nysg:nyng,nxlg:nxrg), &
684	nzb_w_inner(nysg:nyng,nxlg:nxrg), &
685	nzb_w_outer(nysg:nyng,nxlg:nxrg), &
686	nzb_diff_s_inner(nysg:nyng,nxlg:nxrg), &
687	nzb_diff_s_outer(nysg:nyng,nxlg:nxrg), &
688	nzb_local(nysg:nyng,nxlg:nxrg), &
689	nzb_tmp(nysg:nyng,nxlg:nxrg) )
690	!
691	!-- Initialize 2D-index arrays. Note, these will be removed soon!
692	nzb_local(nys:nyn,nxl:nxr) = topo_top_ind(nys:nyn,nxl:nxr,0)
693	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
694	!
695	!-- Check topography for consistency with model domain. Therefore, use
696	!-- maximum and minium topography-top indices. Note, minimum topography top
697	!-- index is already calculated.
698	IF ( TRIM( topography ) /= 'flat' ) THEN
699	#if defined( __parallel )
700	CALL MPI_ALLREDUCE( MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
701	nzb_local_max, 1, MPI_INTEGER, MPI_MAX, comm2d, ierr )
702	#else
703	nzb_local_max = MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
704	#endif
705	nzb_local_min = topo_min_level
706	!
707	!-- Consistency checks
708	IF ( nzb_local_min < 0 .OR. nzb_local_max > nz + 1 ) THEN
709	WRITE( message_string, * ) 'nzb_local values are outside the', &
710	' model domain', &
711	'&MINVAL( nzb_local ) = ', nzb_local_min, &
712	'&MAXVAL( nzb_local ) = ', nzb_local_max
713	CALL message( 'init_grid', 'PA0210', 1, 2, 0, 6, 0 )
714	ENDIF
715	ENDIF
716
717	nzb_s_inner = nzb; nzb_s_outer = nzb
718	nzb_u_inner = nzb; nzb_u_outer = nzb
719	nzb_v_inner = nzb; nzb_v_outer = nzb
720	nzb_w_inner = nzb; nzb_w_outer = nzb
721
722	!
723	!-- Define vertical gridpoint from (or to) which on the usual finite difference
724	!-- form (which does not use surface fluxes) is applied
725	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
726	nzb_diff = nzb + 2
727	ELSE
728	nzb_diff = nzb + 1
729	ENDIF
730
731	nzb_diff_s_inner = nzb_diff; nzb_diff_s_outer = nzb_diff
732	!
733	!-- Set Neumann conditions for topography. Will be removed soon.
734	IF ( .NOT. bc_ns_cyc ) THEN
735	IF ( nys == 0 ) THEN
736	DO i = 1, nbgp
737	nzb_local(nys-i,:) = nzb_local(nys,:)
738	ENDDO
739	ELSEIF ( nyn == ny ) THEN
740	DO i = 1, nbgp
741	nzb_local(ny+i,:) = nzb_local(ny,:)
742	ENDDO
743	ENDIF
744	ENDIF
745
746	IF ( .NOT. bc_lr_cyc ) THEN
747	IF ( nxl == 0 ) THEN
748	DO i = 1, nbgp
749	nzb_local(:,nxl-i) = nzb_local(:,nxl)
750	ENDDO
751	ELSEIF ( nxr == nx ) THEN
752	DO i = 1, nbgp
753	nzb_local(:,nx+i) = nzb_local(:,nx)
754	ENDDO
755	ENDIF
756	ENDIF
757	!
758	!-- Initialization of 2D index arrays, will be removed soon!
759	!-- Initialize nzb_s_inner and nzb_w_inner
760	nzb_s_inner = nzb_local
761	nzb_w_inner = nzb_local
762
763	!
764	!-- Initialize remaining index arrays:
765	!-- first pre-initialize them with nzb_s_inner...
766	nzb_u_inner = nzb_s_inner
767	nzb_u_outer = nzb_s_inner
768	nzb_v_inner = nzb_s_inner
769	nzb_v_outer = nzb_s_inner
770	nzb_w_outer = nzb_s_inner
771	nzb_s_outer = nzb_s_inner
772
773	!
774	!-- nzb_s_outer:
775	!-- extend nzb_local east-/westwards first, then north-/southwards
776	nzb_tmp = nzb_local
777	DO j = nys, nyn
778	DO i = nxl, nxr
779	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i), &
780	nzb_local(j,i+1) )
781	ENDDO
782	ENDDO
783
784	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
785
786	DO i = nxl, nxr
787	DO j = nys, nyn
788	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
789	nzb_tmp(j+1,i) )
790	ENDDO
791	!
792	!-- non-cyclic boundary conditions (overwritten by call of
793	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
794	IF ( nys == 0 ) THEN
795	j = -1
796	nzb_s_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
797	ENDIF
798	IF ( nyn == ny ) THEN
799	j = ny + 1
800	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
801	ENDIF
802	ENDDO
803	!
804	!-- nzb_w_outer:
805	!-- identical to nzb_s_outer
806	nzb_w_outer = nzb_s_outer
807	!
808	!-- nzb_u_inner:
809	!-- extend nzb_local rightwards only
810	nzb_tmp = nzb_local
811	DO j = nys, nyn
812	DO i = nxl, nxr
813	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i) )
814	ENDDO
815	ENDDO
816
817	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
818
819	nzb_u_inner = nzb_tmp
820	!
821	!-- nzb_u_outer:
822	!-- extend current nzb_tmp (nzb_u_inner) north-/southwards
823	DO i = nxl, nxr
824	DO j = nys, nyn
825	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
826	nzb_tmp(j+1,i) )
827	ENDDO
828	!
829	!-- non-cyclic boundary conditions (overwritten by call of
830	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
831	IF ( nys == 0 ) THEN
832	j = -1
833	nzb_u_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
834	ENDIF
835	IF ( nyn == ny ) THEN
836	j = ny + 1
837	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
838	ENDIF
839	ENDDO
840
841	!
842	!-- nzb_v_inner:
843	!-- extend nzb_local northwards only
844	nzb_tmp = nzb_local
845	DO i = nxl, nxr
846	DO j = nys, nyn
847	nzb_tmp(j,i) = MAX( nzb_local(j-1,i), nzb_local(j,i) )
848	ENDDO
849	ENDDO
850
851	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
852	nzb_v_inner = nzb_tmp
853
854	!
855	!-- nzb_v_outer:
856	!-- extend current nzb_tmp (nzb_v_inner) right-/leftwards
857	DO j = nys, nyn
858	DO i = nxl, nxr
859	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i), &
860	nzb_tmp(j,i+1) )
861	ENDDO
862	!
863	!-- non-cyclic boundary conditions (overwritten by call of
864	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
865	IF ( nxl == 0 ) THEN
866	i = -1
867	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i+1), nzb_tmp(j,i) )
868	ENDIF
869	IF ( nxr == nx ) THEN
870	i = nx + 1
871	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i) )
872	ENDIF
873	ENDDO
874
875	!
876	!-- Exchange of lateral boundary values (parallel computers) and cyclic
877	!-- boundary conditions, if applicable.
878	!-- Since nzb_s_inner and nzb_w_inner are derived directly from nzb_local
879	!-- they do not require exchange and are not included here.
880	CALL exchange_horiz_2d_int( nzb_u_inner, nys, nyn, nxl, nxr, nbgp )
881	CALL exchange_horiz_2d_int( nzb_u_outer, nys, nyn, nxl, nxr, nbgp )
882	CALL exchange_horiz_2d_int( nzb_v_inner, nys, nyn, nxl, nxr, nbgp )
883	CALL exchange_horiz_2d_int( nzb_v_outer, nys, nyn, nxl, nxr, nbgp )
884	CALL exchange_horiz_2d_int( nzb_w_outer, nys, nyn, nxl, nxr, nbgp )
885	CALL exchange_horiz_2d_int( nzb_s_outer, nys, nyn, nxl, nxr, nbgp )
886
887	!
888	!-- Set the individual index arrays which define the k index from which on
889	!-- the usual finite difference form (which does not use surface fluxes) is
890	!-- applied
891	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
892	nzb_diff_s_inner = nzb_s_inner + 2
893	nzb_diff_s_outer = nzb_s_outer + 2
894	ELSE
895	nzb_diff_s_inner = nzb_s_inner + 1
896	nzb_diff_s_outer = nzb_s_outer + 1
897	ENDIF
898	!
899	!-- Vertical nesting: communicate vertical grid level arrays between fine and
900	!-- coarse grid
901	IF ( vnested ) CALL vnest_init_grid
902
903	END SUBROUTINE init_grid
904
905
906	! Description:
907	! -----------------------------------------------------------------------------!
908	!> Calculation of the stretching factor through an iterative method. Ideas were
909	!> taken from the paper "Regional stretched grid generation and its application
910	!> to the NCAR RegCM (1999)". Normally, no analytic solution exists because the
911	!> system of equations has two variables (r,l) but four requirements
912	!> (l=integer, r=[0,88;1,2], Eq(6), Eq(5) starting from index j=1) which
913	!> results into an overdetermined system.
914	!------------------------------------------------------------------------------!
915	SUBROUTINE calculate_stretching_factor( number_end )
916
917	USE control_parameters, &
918	ONLY: dz, dz_stretch_factor_array, &
919	dz_stretch_level_end, dz_stretch_level_start, message_string
920
921	USE kinds
922
923	IMPLICIT NONE
924
925	INTEGER(iwp) :: iterations !< number of iterations until stretch_factor_lower/upper_limit is reached
926	INTEGER(iwp) :: l_rounded !< after l_rounded grid levels dz(n) is strechted to dz(n+1) with stretch_factor_2
927	INTEGER(iwp) :: n !< loop variable for stretching
928
929	INTEGER(iwp), INTENT(IN) :: number_end !< number of user-specified end levels for stretching
930
931	REAL(wp) :: delta_l !< absolute difference between l and l_rounded
932	REAL(wp) :: delta_stretch_factor !< absolute difference between stretch_factor_1 and stretch_factor_2
933	REAL(wp) :: delta_total_new !< sum of delta_l and delta_stretch_factor for the next iteration (should be as small as possible)
934	REAL(wp) :: delta_total_old !< sum of delta_l and delta_stretch_factor for the last iteration
935	REAL(wp) :: distance !< distance between dz_stretch_level_start and dz_stretch_level_end (stretching region)
936	REAL(wp) :: l !< value that fulfil Eq. (5) in the paper mentioned above together with stretch_factor_1 exactly
937	REAL(wp) :: numerator !< numerator of the quotient
938	REAL(wp) :: stretch_factor_1 !< stretching factor that fulfil Eq. (5) togehter with l exactly
939	REAL(wp) :: stretch_factor_2 !< stretching factor that fulfil Eq. (6) togehter with l_rounded exactly
940
941	REAL(wp) :: dz_stretch_factor_array_2(9) = 1.08_wp !< Array that contains all stretch_factor_2 that belongs to stretch_factor_1
942
943	REAL(wp), PARAMETER :: stretch_factor_interval = 1.0E-06 !< interval for sampling possible stretching factors
944	REAL(wp), PARAMETER :: stretch_factor_lower_limit = 0.88 !< lowest possible stretching factor
945	REAL(wp), PARAMETER :: stretch_factor_upper_limit = 1.12 !< highest possible stretching factor
946
947
948	l = 0
949	DO n = 1, number_end
950
951	iterations = 1
952	stretch_factor_1 = 1.0
953	stretch_factor_2 = 1.0
954	delta_total_old = 1.0
955
956	IF ( dz(n) > dz(n+1) ) THEN
957	DO WHILE ( stretch_factor_1 >= stretch_factor_lower_limit )
958
959	stretch_factor_1 = 1.0 - iterations * stretch_factor_interval
960	distance = ABS( dz_stretch_level_end(n) - &
961	dz_stretch_level_start(n) )
962	numerator = distance*stretch_factor_1/dz(n) + &
963	stretch_factor_1 - distance/dz(n)
964
965	IF ( numerator > 0.0 ) THEN
966	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0
967	l_rounded = NINT( l )
968	delta_l = ABS( l_rounded - l ) / l
969	ENDIF
970
971	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
972
973	delta_stretch_factor = ABS( stretch_factor_1 - &
974	stretch_factor_2 ) / &
975	stretch_factor_2
976
977	delta_total_new = delta_l + delta_stretch_factor
978
979	!
980	!-- stretch_factor_1 is taken to guarantee that the stretching
981	!-- procedure ends as close as possible to dz_stretch_level_end.
982	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
983	!-- equal to dz(n+1) after l_rounded grid levels.
984	IF (delta_total_new < delta_total_old) THEN
985	dz_stretch_factor_array(n) = stretch_factor_1
986	dz_stretch_factor_array_2(n) = stretch_factor_2
987	delta_total_old = delta_total_new
988	ENDIF
989
990	iterations = iterations + 1
991
992	ENDDO
993
994	ELSEIF ( dz(n) < dz(n+1) ) THEN
995	DO WHILE ( stretch_factor_1 <= stretch_factor_upper_limit )
996
997	stretch_factor_1 = 1.0 + iterations * stretch_factor_interval
998	distance = ABS( dz_stretch_level_end(n) - &
999	dz_stretch_level_start(n) )
1000	numerator = distance*stretch_factor_1/dz(n) + &
1001	stretch_factor_1 - distance/dz(n)
1002
1003	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0
1004	l_rounded = NINT( l )
1005	delta_l = ABS( l_rounded - l ) / l
1006
1007	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
1008
1009	delta_stretch_factor = ABS( stretch_factor_1 - &
1010	stretch_factor_2 ) / &
1011	stretch_factor_2
1012
1013	delta_total_new = delta_l + delta_stretch_factor
1014
1015	!
1016	!-- stretch_factor_1 is taken to guarantee that the stretching
1017	!-- procedure ends as close as possible to dz_stretch_level_end.
1018	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
1019	!-- equal to dz(n+1) after l_rounded grid levels.
1020	IF (delta_total_new < delta_total_old) THEN
1021	dz_stretch_factor_array(n) = stretch_factor_1
1022	dz_stretch_factor_array_2(n) = stretch_factor_2
1023	delta_total_old = delta_total_new
1024	ENDIF
1025
1026	iterations = iterations + 1
1027	ENDDO
1028
1029	ELSE
1030	message_string= 'Two adjacent values of dz must be different'
1031	CALL message( 'init_grid', 'PA0228', 1, 2, 0, 6, 0 )
1032
1033	ENDIF
1034
1035	!
1036	!-- Check if also the second stretching factor fits into the allowed
1037	!-- interval. If not, print a warning for the user.
1038	IF ( dz_stretch_factor_array_2(n) < stretch_factor_lower_limit .OR. &
1039	dz_stretch_factor_array_2(n) > stretch_factor_upper_limit ) THEN
1040	WRITE( message_string, * ) 'stretch_factor_2 = ', &
1041	dz_stretch_factor_array_2(n), ' which is',&
1042	' responsible for exactly reaching& dz =',&
1043	dz(n+1), 'after a specific amount of', &
1044	' grid levels& exceeds the upper', &
1045	' limit =', stretch_factor_upper_limit, &
1046	' &or lower limit = ', &
1047	stretch_factor_lower_limit
1048	CALL message( 'init_grid', 'PA0499', 0, 1, 0, 6, 0 )
1049
1050	ENDIF
1051	ENDDO
1052
1053	END SUBROUTINE calculate_stretching_factor
1054
1055
1056	! Description:
1057	! -----------------------------------------------------------------------------!
1058	!> Set temporary topography flags and reference buildings on top of underlying
1059	!> orography.
1060	!------------------------------------------------------------------------------!
1061	SUBROUTINE process_topography( topo_3d )
1062
1063	USE arrays_3d, &
1064	ONLY: zu, zw
1065
1066	USE control_parameters, &
1067	ONLY: bc_lr_cyc, bc_ns_cyc, message_string, ocean_mode
1068
1069	USE indices, &
1070	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
1071	nzt
1072
1073	USE netcdf_data_input_mod, &
1074	ONLY: buildings_f, building_id_f, building_type_f, input_pids_static, &
1075	terrain_height_f
1076
1077	USE kinds
1078
1079	USE pegrid
1080
1081	IMPLICIT NONE
1082
1083	INTEGER(iwp) :: i !< running index along x-direction
1084	INTEGER(iwp) :: j !< running index along y-direction
1085	INTEGER(iwp) :: k !< running index along z-direction with respect to numeric grid
1086	INTEGER(iwp) :: k2 !< running index along z-direction with respect to netcdf grid
1087	INTEGER(iwp) :: nr !< index variable indication maximum terrain height for respective building ID
1088	INTEGER(iwp) :: num_build !< counter for number of buildings
1089	INTEGER(iwp) :: topo_top_index !< orography top index, used to map 3D buildings onto terrain
1090
1091	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displace_dum !< displacements of start addresses, used for MPI_ALLGATHERV
1092	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids !< building IDs on entire model domain
1093	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final !< building IDs on entire model domain, multiple occurences are sorted out
1094	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final_tmp !< temporary array used for resizing
1095	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l !< building IDs on local subdomain
1096	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l_tmp !< temporary array used to resize array of building IDs
1097
1098	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings !< number of buildings with different ID on entire model domain
1099	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings_l !< number of buildings with different ID on local subdomain
1100
1101	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< input array for 3D topography and dummy array for setting "outer"-flags
1102
1103	REAL(wp) :: ocean_offset !< offset to consider inverse vertical coordinate at topography definition
1104	REAL(wp) :: oro_min = 0.0_wp !< minimum terrain height in entire model domain, used to reference terrain to zero
1105	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max !< maximum terrain height occupied by an building with certain id
1106	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max_l !< maximum terrain height occupied by an building with certain id, on local subdomain
1107
1108	!
1109	!-- Reference lowest terrain height to zero. In case the minimum terrain height
1110	!-- is non-zero, all grid points of the lower vertical grid levels might be
1111	!-- entirely below the surface, meaning a waste of computational resources.
1112	!-- In order to avoid this, remove the lowest terrain height. Please note,
1113	!-- in case of a nested run, the global minimum from all parent and childs
1114	!-- need to be remove to avoid steep edges at the child-domain boundaries.
1115	IF ( input_pids_static ) THEN
1116
1117	#if defined( __parallel )
1118	CALL MPI_ALLREDUCE( MINVAL( terrain_height_f%var ), oro_min, 1, &
1119	MPI_REAL, MPI_MIN, MPI_COMM_WORLD, ierr )
1120	#else
1121	oro_min = MINVAL( terrain_height_f%var )
1122	#endif
1123	terrain_height_f%var = terrain_height_f%var - oro_min
1124	!
1125	!-- Give an informative message that terrain height is referenced to zero
1126	IF ( oro_min > 0.0_wp ) THEN
1127	WRITE( message_string, * ) 'Terrain height was internally shifted '//&
1128	'downwards by ', oro_min, 'meter(s) to save ' // &
1129	'computational resources.'
1130	CALL message( 'init_grid', 'PA0505', 0, 0, 0, 6, 0 )
1131	ENDIF
1132	ENDIF
1133
1134	!
1135	!-- In the following, buildings and orography are further preprocessed
1136	!-- before they are mapped on the LES grid.
1137	!-- Buildings are mapped on top of the orography by maintaining the roof
1138	!-- shape of the building. This can be achieved by referencing building on
1139	!-- top of the maximum terrain height within the area occupied by the
1140	!-- respective building. As buildings and terrain height are defined PE-wise,
1141	!-- parallelization of this referencing is required (a building can be
1142	!-- distributed between different PEs).
1143	!-- In a first step, determine the number of buildings with different
1144	!-- building id on each PE. In a next step, all building ids are gathered
1145	!-- into one array which is present to all PEs. For each building ID,
1146	!-- the maximum terrain height occupied by the respective building is
1147	!-- computed and distributed to each PE.
1148	!-- Finally, for each building id and its respective reference orography,
1149	!-- builidings are mapped on top.
1150	!--
1151	!-- First, pre-set topography flags, bit 1 indicates orography, bit 2
1152	!-- buildings
1153	!-- classify the respective surfaces.
1154	topo_3d = IBSET( topo_3d, 0 )
1155	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1156	!
1157	!-- In order to map topography on PALM grid also in case of ocean simulations,
1158	!-- pre-calculate an offset value.
1159	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1160	!
1161	!-- Reference buildings on top of orography. This is not necessary
1162	!-- if topography is read from ASCII file as no distinction between buildings
1163	!-- and terrain height can be made. Moreover, this is also not necessary if
1164	!-- urban-surface and land-surface model are used at the same time.
1165	IF ( input_pids_static ) THEN
1166
1167	IF ( buildings_f%from_file ) THEN
1168	num_buildings_l = 0
1169	num_buildings = 0
1170	!
1171	!-- Allocate at least one element for building ids and give it an inital
1172	!-- negative value that will be overwritten later. This, however, is
1173	!-- necessary in case there all IDs in the model domain are fill values.
1174	ALLOCATE( build_ids_l(1) )
1175	build_ids_l = -1
1176	DO i = nxl, nxr
1177	DO j = nys, nyn
1178	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1179	IF ( num_buildings_l(myid) > 0 ) THEN
1180	IF ( ANY( building_id_f%var(j,i) == build_ids_l ) ) &
1181	THEN
1182	CYCLE
1183	ELSE
1184	num_buildings_l(myid) = num_buildings_l(myid) + 1
1185	!
1186	!-- Resize array with different local building ids
1187	ALLOCATE( build_ids_l_tmp(1:SIZE(build_ids_l)) )
1188	build_ids_l_tmp = build_ids_l
1189	DEALLOCATE( build_ids_l )
1190	ALLOCATE( build_ids_l(1:num_buildings_l(myid)) )
1191	build_ids_l(1:num_buildings_l(myid)-1) = &
1192	build_ids_l_tmp(1:num_buildings_l(myid)-1)
1193	build_ids_l(num_buildings_l(myid)) = building_id_f%var(j,i)
1194	DEALLOCATE( build_ids_l_tmp )
1195	ENDIF
1196	!
1197	!-- First occuring building id on PE
1198	ELSE
1199	num_buildings_l(myid) = num_buildings_l(myid) + 1
1200	build_ids_l(1) = building_id_f%var(j,i)
1201	ENDIF
1202	ENDIF
1203	ENDDO
1204	ENDDO
1205	!
1206	!-- Determine number of different building ids for the entire domain
1207	#if defined( __parallel )
1208	CALL MPI_ALLREDUCE( num_buildings_l, num_buildings, numprocs, &
1209	MPI_INTEGER, MPI_SUM, comm2d, ierr )
1210	#else
1211	num_buildings = num_buildings_l
1212	#endif
1213	!
1214	!-- Gather all buildings ids on each PEs.
1215	!-- First, allocate array encompassing all building ids in model domain.
1216	ALLOCATE( build_ids(1:SUM(num_buildings)) )
1217	#if defined( __parallel )
1218	!
1219	!-- Allocate array for displacements.
1220	!-- As each PE may has a different number of buildings, so that
1221	!-- the block sizes send by each PE may not be equal. Hence,
1222	!-- information about the respective displacement is required, indicating
1223	!-- the respective adress where each MPI-task writes into the receive
1224	!-- buffer array
1225	ALLOCATE( displace_dum(0:numprocs-1) )
1226	displace_dum(0) = 0
1227	DO i = 1, numprocs-1
1228	displace_dum(i) = displace_dum(i-1) + num_buildings(i-1)
1229	ENDDO
1230
1231	CALL MPI_ALLGATHERV( build_ids_l(1:num_buildings_l(myid)), &
1232	num_buildings(myid), &
1233	MPI_INTEGER, &
1234	build_ids, &
1235	num_buildings, &
1236	displace_dum, &
1237	MPI_INTEGER, &
1238	comm2d, ierr )
1239
1240	DEALLOCATE( displace_dum )
1241
1242	#else
1243	build_ids = build_ids_l
1244	#endif
1245
1246	!
1247	!-- Note, in parallel mode building ids can occure mutliple times, as
1248	!-- each PE has send its own ids. Therefore, sort out building ids which
1249	!-- appear more than one time.
1250	num_build = 0
1251	DO nr = 1, SIZE(build_ids)
1252
1253	IF ( ALLOCATED(build_ids_final) ) THEN
1254	IF ( ANY( build_ids(nr) == build_ids_final ) ) THEN
1255	CYCLE
1256	ELSE
1257	num_build = num_build + 1
1258	!
1259	!-- Resize
1260	ALLOCATE( build_ids_final_tmp(1:num_build) )
1261	build_ids_final_tmp(1:num_build-1) = build_ids_final(1:num_build-1)
1262	DEALLOCATE( build_ids_final )
1263	ALLOCATE( build_ids_final(1:num_build) )
1264	build_ids_final(1:num_build-1) = build_ids_final_tmp(1:num_build-1)
1265	build_ids_final(num_build) = build_ids(nr)
1266	DEALLOCATE( build_ids_final_tmp )
1267	ENDIF
1268	ELSE
1269	num_build = num_build + 1
1270	ALLOCATE( build_ids_final(1:num_build) )
1271	build_ids_final(num_build) = build_ids(nr)
1272	ENDIF
1273	ENDDO
1274
1275	!
1276	!-- Determine maximumum terrain height occupied by the respective
1277	!-- building and temporalily store on oro_max
1278	ALLOCATE( oro_max_l(1:SIZE(build_ids_final)) )
1279	ALLOCATE( oro_max(1:SIZE(build_ids_final)) )
1280	oro_max_l = 0.0_wp
1281
1282	DO nr = 1, SIZE(build_ids_final)
1283	oro_max_l(nr) = MAXVAL( &
1284	MERGE( terrain_height_f%var(nys:nyn,nxl:nxr), &
1285	0.0_wp, &
1286	building_id_f%var(nys:nyn,nxl:nxr) == &
1287	build_ids_final(nr) ) )
1288	ENDDO
1289
1290	#if defined( __parallel )
1291	IF ( SIZE(build_ids_final) >= 1 ) THEN
1292	CALL MPI_ALLREDUCE( oro_max_l, oro_max, SIZE( oro_max ), MPI_REAL,&
1293	MPI_MAX, comm2d, ierr )
1294	ENDIF
1295	#else
1296	oro_max = oro_max_l
1297	#endif
1298	!
1299	!-- Finally, determine discrete grid height of maximum orography occupied
1300	!-- by a building. Use all-or-nothing approach, i.e. if terrain
1301	!-- exceeds the scalar level the grid box is fully terrain and the
1302	!-- maximum terrain is set to the zw level.
1303	!-- terrain or
1304	oro_max_l = 0.0
1305	DO nr = 1, SIZE(build_ids_final)
1306	DO k = nzb, nzt
1307	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1308	oro_max_l(nr) = zw(k) - ocean_offset
1309	ENDDO
1310	oro_max(nr) = oro_max_l(nr)
1311	ENDDO
1312	ENDIF
1313	!
1314	!-- Map orography as well as buildings onto grid.
1315	DO i = nxl, nxr
1316	DO j = nys, nyn
1317	topo_top_index = 0
1318	!
1319	!-- Obtain index in global building_id array
1320	IF ( buildings_f%from_file ) THEN
1321	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1322	!
1323	!-- Determine index where maximum terrain height occupied by
1324	!-- the respective building height is stored.
1325	nr = MINLOC( ABS( build_ids_final - &
1326	building_id_f%var(j,i) ), DIM = 1 )
1327	ENDIF
1328	ENDIF
1329	DO k = nzb, nzt
1330	!
1331	!-- In a first step, if grid point is below or equal the given
1332	!-- terrain height, grid point is flagged to be of type natural.
1333	!-- Please note, in case there is also a building which is lower
1334	!-- than the vertical grid spacing, initialization of surface
1335	!-- attributes will not be correct as given surface information
1336	!-- will not be in accordance to the classified grid points.
1337	!-- Hence, in this case, also a building flag.
1338	IF ( zu(k) - ocean_offset <= terrain_height_f%var(j,i) ) THEN
1339	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1340	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1341	topo_top_index = k ! topo_top_index + 1
1342	ENDIF
1343	!
1344	!-- Set building grid points. Here, only consider 2D buildings.
1345	!-- 3D buildings require separate treatment.
1346	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1347	!
1348	!-- Fill-up the terrain to the level of maximum orography
1349	!-- within the building-covered area.
1350	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1351	!
1352	!-- Note, oro_max is always on zw level
1353	IF ( zu(k) - ocean_offset < oro_max(nr) ) THEN
1354	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1355	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1356	ELSEIF ( zu(k) - ocean_offset <= &
1357	oro_max(nr) + buildings_f%var_2d(j,i) ) THEN
1358	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1359	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1360	ENDIF
1361	ENDIF
1362	ENDIF
1363	ENDDO
1364	!
1365	!-- Special treatment for non grid-resolved buildings. This case,
1366	!-- the uppermost terrain grid point is flagged as building as well
1367	!-- well, even though no building exists at all. However, the
1368	!-- surface element will be identified as urban-surface and the
1369	!-- input data provided by the drivers is consistent to the surface
1370	!-- classification. Else, all non grid-resolved buildings would vanish
1371	!-- and identified as terrain grid points, which, however, won't be
1372	!-- consistent with the input data.
1373	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1374	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1375	DO k = nzb, nzt
1376	IF( zw(k) - ocean_offset == oro_max(nr) ) THEN
1377	IF ( buildings_f%var_2d(j,i) <= zu(k+1) - zw(k) ) THEN
1378	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1379	ENDIF
1380	ENDIF
1381	ENDDO
1382	ENDIF
1383	ENDIF
1384	!
1385	!-- Map 3D buildings onto terrain height.
1386	!-- In case of any slopes, map building on top of maximum terrain
1387	!-- height covered by the building. In other words, extend
1388	!-- building down to the respective local terrain-surface height.
1389	IF ( buildings_f%from_file .AND. buildings_f%lod == 2 ) THEN
1390	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1391	!
1392	!-- Extend building down to the terrain surface, i.e. fill-up
1393	!-- surface irregularities below a building. Note, oro_max
1394	!-- is already a discrete height according to the all-or-nothing
1395	!-- approach, i.e. grid box is either topography or atmosphere,
1396	!-- terrain top is defined at upper bound of the grid box.
1397	!-- Hence, check for zw in this case.
1398	!-- Note, do this only for buildings which are surface mounted,
1399	!-- i.e. building types 1-6. Below bridges, which are represented
1400	!-- exclusively by building type 7, terrain shape should be
1401	!-- maintained.
1402	IF ( building_type_f%from_file ) THEN
1403	IF ( building_type_f%var(j,i) /= 7 ) THEN
1404	DO k = topo_top_index + 1, nzt + 1
1405	IF ( zu(k) - ocean_offset <= oro_max(nr) ) THEN
1406	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1407	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1408	ENDIF
1409	ENDDO
1410	!
1411	!-- After surface irregularities are smoothen, determine
1412	!-- lower start index where building starts.
1413	DO k = nzb, nzt
1414	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1415	topo_top_index = k
1416	ENDDO
1417	ENDIF
1418	ENDIF
1419	!
1420	!-- Finally, map building on top.
1421	k2 = 0
1422	DO k = topo_top_index, nzt + 1
1423	IF ( k2 <= buildings_f%nz-1 ) THEN
1424	IF ( buildings_f%var_3d(k2,j,i) == 1 ) THEN
1425	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1426	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1427	ENDIF
1428	ENDIF
1429	k2 = k2 + 1
1430	ENDDO
1431	ENDIF
1432	ENDIF
1433	ENDDO
1434	ENDDO
1435	!
1436	!-- Deallocate temporary arrays required for processing and reading data
1437	IF ( ALLOCATED( oro_max ) ) DEALLOCATE( oro_max )
1438	IF ( ALLOCATED( oro_max_l ) ) DEALLOCATE( oro_max_l )
1439	IF ( ALLOCATED( build_ids_final ) ) DEALLOCATE( build_ids_final )
1440	!
1441	!-- Topography input via ASCII format.
1442	ELSE
1443	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1444	!
1445	!-- Initialize topography bit 0 (indicates obstacle) everywhere to zero
1446	!-- and clear all grid points at nzb, where alway a surface is defined.
1447	!-- Further, set also bit 1 (indicates terrain) at nzb, which is further
1448	!-- used for masked data output and further processing. Note, in the
1449	!-- ASCII case no distinction is made between buildings and terrain,
1450	!-- so that setting of bit 1 and 2 at the same time has no effect.
1451	topo_3d = IBSET( topo_3d, 0 )
1452	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1453	topo_3d(nzb,:,:) = IBSET( topo_3d(nzb,:,:), 1 )
1454	DO i = nxl, nxr
1455	DO j = nys, nyn
1456	DO k = nzb, nzt
1457	!
1458	!-- Flag topography for all grid points which are below
1459	!-- the local topography height.
1460	!-- Note, each topography is flagged as building.
1461	IF ( zu(k) - ocean_offset <= buildings_f%var_2d(j,i) ) THEN
1462	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1463	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 ) !indicates building
1464	ENDIF
1465	ENDDO
1466	ENDDO
1467	ENDDO
1468	ENDIF
1469
1470	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1471
1472	IF ( .NOT. bc_ns_cyc ) THEN
1473	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1474	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1475	ENDIF
1476
1477	IF ( .NOT. bc_lr_cyc ) THEN
1478	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1479	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1480	ENDIF
1481
1482	END SUBROUTINE process_topography
1483
1484
1485	! Description:
1486	! -----------------------------------------------------------------------------!
1487	!> Filter topography, i.e. fill holes resolved by only one grid point.
1488	!> Such holes are suspected to lead to velocity blow-ups as continuity
1489	!> equation on discrete grid cannot be fulfilled in such case.
1490	!------------------------------------------------------------------------------!
1491	SUBROUTINE filter_topography( topo_3d )
1492
1493	USE control_parameters, &
1494	ONLY: bc_lr_cyc, bc_ns_cyc, message_string
1495
1496	USE indices, &
1497	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt
1498
1499	USE netcdf_data_input_mod, &
1500	ONLY: building_id_f, building_type_f
1501
1502	USE pegrid
1503
1504	IMPLICIT NONE
1505
1506	LOGICAL :: filled = .FALSE. !< flag indicating if holes were filled
1507
1508	INTEGER(iwp) :: i !< running index along x-direction
1509	INTEGER(iwp) :: j !< running index along y-direction
1510	INTEGER(iwp) :: k !< running index along z-direction
1511	INTEGER(iwp) :: num_hole !< number of holes (in topography) resolved by only one grid point
1512	INTEGER(iwp) :: num_hole_l !< number of holes (in topography) resolved by only one grid point on local PE
1513	INTEGER(iwp) :: num_wall !< number of surrounding vertical walls for a single grid point
1514
1515	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo_tmp !< temporary 3D-topography used to fill holes
1516	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< 3D-topography array merging buildings and orography
1517	!
1518	!-- Before checking for holes, set lateral boundary conditions for
1519	!-- topography. After hole-filling, boundary conditions must be set again.
1520	!-- Several iterations are performed, in order to fill holes which might
1521	!-- emerge by the filling-algorithm itself.
1522	ALLOCATE( topo_tmp(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
1523	topo_tmp = 0
1524
1525	num_hole = 99999
1526	DO WHILE ( num_hole > 0 )
1527
1528	num_hole = 0
1529	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1530	!
1531	!-- Exchange also building ID and type. Note, building_type is an one-byte
1532	!-- variable.
1533	IF ( building_id_f%from_file ) &
1534	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1535	IF ( building_type_f%from_file ) &
1536	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1537
1538	topo_tmp = topo_3d
1539	!
1540	!-- In case of non-cyclic lateral boundaries, assume lateral boundary to be
1541	!-- a solid wall. Thus, intermediate spaces of one grid point between
1542	!-- boundary and some topographic structure will be filled.
1543	IF ( .NOT. bc_ns_cyc ) THEN
1544	IF ( nys == 0 ) topo_tmp(:,-1,:) = IBCLR( topo_tmp(:,0,:), 0 )
1545	IF ( nyn == ny ) topo_tmp(:,ny+1,:) = IBCLR( topo_tmp(:,ny,:), 0 )
1546	ENDIF
1547
1548	IF ( .NOT. bc_lr_cyc ) THEN
1549	IF ( nxl == 0 ) topo_tmp(:,:,-1) = IBCLR( topo_tmp(:,:,0), 0 )
1550	IF ( nxr == nx ) topo_tmp(:,:,nx+1) = IBCLR( topo_tmp(:,:,nx), 0 )
1551	ENDIF
1552
1553	num_hole_l = 0
1554	DO i = nxl, nxr
1555	DO j = nys, nyn
1556	DO k = nzb+1, nzt
1557	IF ( BTEST( topo_tmp(k,j,i), 0 ) ) THEN
1558	num_wall = 0
1559	IF ( .NOT. BTEST( topo_tmp(k,j-1,i), 0 ) ) &
1560	num_wall = num_wall + 1
1561	IF ( .NOT. BTEST( topo_tmp(k,j+1,i), 0 ) ) &
1562	num_wall = num_wall + 1
1563	IF ( .NOT. BTEST( topo_tmp(k,j,i-1), 0 ) ) &
1564	num_wall = num_wall + 1
1565	IF ( .NOT. BTEST( topo_tmp(k,j,i+1), 0 ) ) &
1566	num_wall = num_wall + 1
1567	IF ( .NOT. BTEST( topo_tmp(k-1,j,i), 0 ) ) &
1568	num_wall = num_wall + 1
1569	IF ( .NOT. BTEST( topo_tmp(k+1,j,i), 0 ) ) &
1570	num_wall = num_wall + 1
1571
1572	IF ( num_wall >= 4 ) THEN
1573	num_hole_l = num_hole_l + 1
1574	!
1575	!-- Clear flag 0 and set special flag ( bit 3) to indicate
1576	!-- that new topography point is a result of filtering process.
1577	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1578	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 3 )
1579	!
1580	!-- If filled grid point is occupied by a building, classify
1581	!-- it as building grid point.
1582	IF ( building_type_f%from_file ) THEN
1583	IF ( building_type_f%var(j,i) /= &
1584	building_type_f%fill .OR. &
1585	building_type_f%var(j+1,i) /= &
1586	building_type_f%fill .OR. &
1587	building_type_f%var(j-1,i) /= &
1588	building_type_f%fill .OR. &
1589	building_type_f%var(j,i+1) /= &
1590	building_type_f%fill .OR. &
1591	building_type_f%var(j,i-1) /= &
1592	building_type_f%fill ) THEN
1593	!
1594	!-- Set flag indicating building surfaces
1595	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1596	!
1597	!-- Set building_type and ID at this position if not
1598	!-- already set. This is required for proper
1599	!-- initialization of urban-surface energy balance
1600	!-- solver.
1601	IF ( building_type_f%var(j,i) == &
1602	building_type_f%fill ) THEN
1603
1604	IF ( building_type_f%var(j+1,i) /= &
1605	building_type_f%fill ) THEN
1606	building_type_f%var(j,i) = &
1607	building_type_f%var(j+1,i)
1608	building_id_f%var(j,i) = &
1609	building_id_f%var(j+1,i)
1610	ELSEIF ( building_type_f%var(j-1,i) /= &
1611	building_type_f%fill ) THEN
1612	building_type_f%var(j,i) = &
1613	building_type_f%var(j-1,i)
1614	building_id_f%var(j,i) = &
1615	building_id_f%var(j-1,i)
1616	ELSEIF ( building_type_f%var(j,i+1) /= &
1617	building_type_f%fill ) THEN
1618	building_type_f%var(j,i) = &
1619	building_type_f%var(j,i+1)
1620	building_id_f%var(j,i) = &
1621	building_id_f%var(j,i+1)
1622	ELSEIF ( building_type_f%var(j,i-1) /= &
1623	building_type_f%fill ) THEN
1624	building_type_f%var(j,i) = &
1625	building_type_f%var(j,i-1)
1626	building_id_f%var(j,i) = &
1627	building_id_f%var(j,i-1)
1628	ENDIF
1629	ENDIF
1630	ENDIF
1631	ENDIF
1632	!
1633	!-- If filled grid point is already classified as building
1634	!-- everything is fine, else classify this grid point as
1635	!-- natural type grid point. This case, values for the
1636	!-- surface type are already set.
1637	IF ( .NOT. BTEST( topo_3d(k,j,i), 2 ) ) THEN
1638	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1639	ENDIF
1640	ENDIF
1641	ENDIF
1642	ENDDO
1643	ENDDO
1644	ENDDO
1645	!
1646	!-- Count the total number of holes, required for informative message.
1647	#if defined( __parallel )
1648	CALL MPI_ALLREDUCE( num_hole_l, num_hole, 1, MPI_INTEGER, MPI_SUM, &
1649	comm2d, ierr )
1650	#else
1651	num_hole = num_hole_l
1652	#endif
1653	IF ( num_hole > 0 .AND. .NOT. filled ) filled = .TRUE.
1654
1655	ENDDO
1656	!
1657	!-- Create an informative message if any holes were filled.
1658	IF ( filled ) THEN
1659	WRITE( message_string, * ) 'Topography was filtered, i.e. holes ' // &
1660	'resolved by only one grid point ' // &
1661	'were filled during initialization.'
1662	CALL message( 'init_grid', 'PA0430', 0, 0, 0, 6, 0 )
1663	ENDIF
1664
1665	DEALLOCATE( topo_tmp )
1666	!
1667	!-- Finally, exchange topo_3d array again and if necessary set Neumann boundary
1668	!-- condition in case of non-cyclic lateral boundaries.
1669	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1670
1671	IF ( .NOT. bc_ns_cyc ) THEN
1672	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1673	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1674	ENDIF
1675
1676	IF ( .NOT. bc_lr_cyc ) THEN
1677	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1678	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1679	ENDIF
1680	!
1681	!-- Exchange building ID and type. Note, building_type is an one-byte variable.
1682	IF ( building_id_f%from_file ) &
1683	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1684	IF ( building_type_f%from_file ) &
1685	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1686
1687	END SUBROUTINE filter_topography
1688
1689
1690	! Description:
1691	! -----------------------------------------------------------------------------!
1692	!> Reads topography information from file or sets generic topography. Moreover,
1693	!> all topography-relevant topography arrays are initialized, and grid flags
1694	!> are set.
1695	!------------------------------------------------------------------------------!
1696	SUBROUTINE init_topo( topo )
1697
1698	USE arrays_3d, &
1699	ONLY: zw
1700
1701	USE control_parameters, &
1702	ONLY: bc_lr_cyc, bc_ns_cyc, building_height, building_length_x, &
1703	building_length_y, building_wall_left, building_wall_south, &
1704	canyon_height, canyon_wall_left, canyon_wall_south, &
1705	canyon_width_x, canyon_width_y, dp_level_ind_b, dz, &
1706	message_string, topography, topography_grid_convention, &
1707	tunnel_height, tunnel_length, tunnel_width_x, tunnel_width_y, &
1708	tunnel_wall_depth
1709
1710	USE grid_variables, &
1711	ONLY: dx, dy
1712
1713	USE indices, &
1714	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
1715	nzb, nzt
1716
1717	USE kinds
1718
1719	USE netcdf_data_input_mod, &
1720	ONLY: buildings_f, terrain_height_f
1721
1722	USE pegrid
1723
1724	IMPLICIT NONE
1725
1726	INTEGER(iwp) :: bh !< temporary vertical index of building height
1727	INTEGER(iwp) :: blx !< grid point number of building size along x
1728	INTEGER(iwp) :: bly !< grid point number of building size along y
1729	INTEGER(iwp) :: bxl !< index for left building wall
1730	INTEGER(iwp) :: bxr !< index for right building wall
1731	INTEGER(iwp) :: byn !< index for north building wall
1732	INTEGER(iwp) :: bys !< index for south building wall
1733	INTEGER(iwp) :: ch !< temporary vertical index for canyon height
1734	INTEGER(iwp) :: cwx !< grid point number of canyon size along x
1735	INTEGER(iwp) :: cwy !< grid point number of canyon size along y
1736	INTEGER(iwp) :: cxl !< index for left canyon wall
1737	INTEGER(iwp) :: cxr !< index for right canyon wall
1738	INTEGER(iwp) :: cyn !< index for north canyon wall
1739	INTEGER(iwp) :: cys !< index for south canyon wall
1740	INTEGER(iwp) :: i !< index variable along x
1741	INTEGER(iwp) :: j !< index variable along y
1742	INTEGER(iwp) :: k !< index variable along z
1743	INTEGER(iwp) :: hv_in !< heavyside function to model inner tunnel surface
1744	INTEGER(iwp) :: hv_out !< heavyside function to model outer tunnel surface
1745	INTEGER(iwp) :: txe_out !< end position of outer tunnel wall in x
1746	INTEGER(iwp) :: txs_out !< start position of outer tunnel wall in x
1747	INTEGER(iwp) :: tye_out !< end position of outer tunnel wall in y
1748	INTEGER(iwp) :: tys_out !< start position of outer tunnel wall in y
1749	INTEGER(iwp) :: txe_in !< end position of inner tunnel wall in x
1750	INTEGER(iwp) :: txs_in !< start position of inner tunnel wall in x
1751	INTEGER(iwp) :: tye_in !< end position of inner tunnel wall in y
1752	INTEGER(iwp) :: tys_in !< start position of inner tunnel wall in y
1753	INTEGER(iwp) :: td !< tunnel wall depth
1754	INTEGER(iwp) :: th !< height of outer tunnel wall
1755
1756	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
1757	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
1758	!
1759	!-- Check for correct setting of the namelist parameter topography. If
1760	!-- topography information is read from file but topography = 'flat',
1761	!-- initialization does not properly.
1762	IF ( ( buildings_f%from_file .OR. terrain_height_f%from_file ) .AND. &
1763	TRIM( topography ) /= 'read_from_file' ) THEN
1764	message_string = 'If topography information is provided (via ' // &
1765	'Netcdf or ASCII input) topography = ' // &
1766	'"read_from_file" is required.'
1767	CALL message( 'init_grid', 'PA0437', 1, 2, 0, 6, 0 )
1768	ENDIF
1769	!
1770	!-- Set outer and inner index arrays for non-flat topography.
1771	!-- Here consistency checks concerning domain size and periodicity are
1772	!-- necessary.
1773	!-- Within this SELECT CASE structure only nzb_local is initialized
1774	!-- individually depending on the chosen topography type, all other index
1775	!-- arrays are initialized further below.
1776	SELECT CASE ( TRIM( topography ) )
1777
1778	CASE ( 'flat' )
1779	!
1780	!-- Initialilize 3D topography array, used later for initializing flags
1781	topo(nzb+1:nzt+1,:,:) = IBSET( topo(nzb+1:nzt+1,:,:), 0 )
1782
1783	CASE ( 'single_building' )
1784	!
1785	!-- Single rectangular building, by default centered in the middle of the
1786	!-- total domain
1787	blx = NINT( building_length_x / dx )
1788	bly = NINT( building_length_y / dy )
1789	bh = MINLOC( ABS( zw - building_height ), 1 ) - 1
1790	IF ( ABS( zw(bh) - building_height ) == &
1791	ABS( zw(bh+1) - building_height ) ) bh = bh + 1
1792	IF ( building_wall_left == 9999999.9_wp ) THEN
1793	building_wall_left = ( nx + 1 - blx ) / 2 * dx
1794	ENDIF
1795	bxl = NINT( building_wall_left / dx )
1796	bxr = bxl + blx
1797
1798	IF ( building_wall_south == 9999999.9_wp ) THEN
1799	building_wall_south = ( ny + 1 - bly ) / 2 * dy
1800	ENDIF
1801	bys = NINT( building_wall_south / dy )
1802	byn = bys + bly
1803
1804	!
1805	!-- Building size has to meet some requirements
1806	IF ( ( bxl < 1 ) .OR. ( bxr > nx-1 ) .OR. ( bxr < bxl+3 ) .OR. &
1807	( bys < 1 ) .OR. ( byn > ny-1 ) .OR. ( byn < bys+3 ) ) THEN
1808	WRITE( message_string, * ) 'inconsistent building parameters:', &
1809	'&bxl=', bxl, 'bxr=', bxr, 'bys=', bys, &
1810	'byn=', byn, 'nx=', nx, 'ny=', ny
1811	CALL message( 'init_grid', 'PA0203', 1, 2, 0, 6, 0 )
1812	ENDIF
1813
1814	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1815	nzb_local = 0
1816	!
1817	!-- Define the building.
1818	IF ( bxl <= nxr .AND. bxr >= nxl .AND. &
1819	bys <= nyn .AND. byn >= nys ) &
1820	nzb_local(MAX(nys,bys):MIN(nyn,byn),MAX(nxl,bxl):MIN(nxr,bxr)) = bh
1821	!
1822	!-- Set bit array on basis of nzb_local
1823	DO i = nxl, nxr
1824	DO j = nys, nyn
1825	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1826	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1827	ENDDO
1828	ENDDO
1829
1830	DEALLOCATE( nzb_local )
1831
1832	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1833	!
1834	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1835	!-- boundary conditions for topography.
1836	IF ( .NOT. bc_ns_cyc ) THEN
1837	IF ( nys == 0 ) THEN
1838	DO i = 1, nbgp
1839	topo(:,nys-i,:) = topo(:,nys,:)
1840	ENDDO
1841	ENDIF
1842	IF ( nyn == ny ) THEN
1843	DO i = 1, nbgp
1844	topo(:,nyn+i,:) = topo(:,nyn,:)
1845	ENDDO
1846	ENDIF
1847	ENDIF
1848	IF ( .NOT. bc_lr_cyc ) THEN
1849	IF ( nxl == 0 ) THEN
1850	DO i = 1, nbgp
1851	topo(:,:,nxl-i) = topo(:,:,nxl)
1852	ENDDO
1853	ENDIF
1854	IF ( nxr == nx ) THEN
1855	DO i = 1, nbgp
1856	topo(:,:,nxr+i) = topo(:,:,nxr)
1857	ENDDO
1858	ENDIF
1859	ENDIF
1860
1861	CASE ( 'single_street_canyon' )
1862	!
1863	!-- Single quasi-2D street canyon of infinite length in x or y direction.
1864	!-- The canyon is centered in the other direction by default.
1865	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1866	!
1867	!-- Street canyon in y direction
1868	cwx = NINT( canyon_width_x / dx )
1869	IF ( canyon_wall_left == 9999999.9_wp ) THEN
1870	canyon_wall_left = ( nx + 1 - cwx ) / 2 * dx
1871	ENDIF
1872	cxl = NINT( canyon_wall_left / dx )
1873	cxr = cxl + cwx
1874	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1875	!
1876	!-- Street canyon in x direction
1877	cwy = NINT( canyon_width_y / dy )
1878	IF ( canyon_wall_south == 9999999.9_wp ) THEN
1879	canyon_wall_south = ( ny + 1 - cwy ) / 2 * dy
1880	ENDIF
1881	cys = NINT( canyon_wall_south / dy )
1882	cyn = cys + cwy
1883
1884	ELSE
1885
1886	message_string = 'no street canyon width given'
1887	CALL message( 'init_grid', 'PA0204', 1, 2, 0, 6, 0 )
1888
1889	ENDIF
1890
1891	ch = MINLOC( ABS( zw - canyon_height ), 1 ) - 1
1892	IF ( ABS( zw(ch) - canyon_height ) == &
1893	ABS( zw(ch+1) - canyon_height ) ) ch = ch + 1
1894	dp_level_ind_b = ch
1895	!
1896	!-- Street canyon size has to meet some requirements
1897	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1898	IF ( ( cxl < 1 ) .OR. ( cxr > nx-1 ) .OR. ( cwx < 3 ) .OR. &
1899	( ch < 3 ) ) THEN
1900	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1901	'&cxl=', cxl, ' cxr=', cxr, &
1902	' cwx=', cwx, &
1903	' ch=', ch, ' nx=', nx, ' ny=', ny
1904	CALL message( 'init_grid', 'PA0205', 1, 2, 0, 6, 0 )
1905	ENDIF
1906	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1907	IF ( ( cys < 1 ) .OR. ( cyn > ny-1 ) .OR. ( cwy < 3 ) .OR. &
1908	( ch < 3 ) ) THEN
1909	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1910	'&cys=', cys, ' cyn=', cyn, &
1911	' cwy=', cwy, &
1912	' ch=', ch, ' nx=', nx, ' ny=', ny
1913	CALL message( 'init_grid', 'PA0206', 1, 2, 0, 6, 0 )
1914	ENDIF
1915	ENDIF
1916	IF ( canyon_width_x /= 9999999.9_wp .AND. &
1917	canyon_width_y /= 9999999.9_wp ) THEN
1918	message_string = 'inconsistent canyon parameters:' // &
1919	'&street canyon can only be oriented' // &
1920	' either in x- or in y-direction'
1921	CALL message( 'init_grid', 'PA0207', 1, 2, 0, 6, 0 )
1922	ENDIF
1923
1924	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1925	nzb_local = ch
1926	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1927	IF ( cxl <= nxr .AND. cxr >= nxl ) &
1928	nzb_local(:,MAX(nxl,cxl+1):MIN(nxr,cxr-1)) = 0
1929	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1930	IF ( cys <= nyn .AND. cyn >= nys ) &
1931	nzb_local(MAX(nys,cys+1):MIN(nyn,cyn-1),:) = 0
1932	ENDIF
1933	!
1934	!-- Set bit array on basis of nzb_local
1935	DO i = nxl, nxr
1936	DO j = nys, nyn
1937	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1938	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1939	ENDDO
1940	ENDDO
1941	DEALLOCATE( nzb_local )
1942
1943	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1944	!
1945	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1946	!-- boundary conditions for topography.
1947	IF ( .NOT. bc_ns_cyc ) THEN
1948	IF ( nys == 0 ) THEN
1949	DO i = 1, nbgp
1950	topo(:,nys-i,:) = topo(:,nys,:)
1951	ENDDO
1952	ENDIF
1953	IF ( nyn == ny ) THEN
1954	DO i = 1, nbgp
1955	topo(:,nyn+i,:) = topo(:,nyn,:)
1956	ENDDO
1957	ENDIF
1958	ENDIF
1959	IF ( .NOT. bc_lr_cyc ) THEN
1960	IF ( nxl == 0 ) THEN
1961	DO i = 1, nbgp
1962	topo(:,:,nxl-i) = topo(:,:,nxl)
1963	ENDDO
1964	ENDIF
1965	IF ( nxr == nx ) THEN
1966	DO i = 1, nbgp
1967	topo(:,:,nxr+i) = topo(:,:,nxr)
1968	ENDDO
1969	ENDIF
1970	ENDIF
1971
1972	CASE ( 'tunnel' )
1973
1974	!
1975	!-- Tunnel height
1976	IF ( tunnel_height == 9999999.9_wp ) THEN
1977	th = zw( INT( 0.2 * nz) )
1978	ELSE
1979	th = tunnel_height
1980	ENDIF
1981	!
1982	!-- Tunnel-wall depth
1983	IF ( tunnel_wall_depth == 9999999.9_wp ) THEN
1984	td = MAX ( dx, dy, dz(1) )
1985	ELSE
1986	td = tunnel_wall_depth
1987	ENDIF
1988	!
1989	!-- Check for tunnel width
1990	IF ( tunnel_width_x == 9999999.9_wp .AND. &
1991	tunnel_width_y == 9999999.9_wp ) THEN
1992	message_string = 'No tunnel width is given. '
1993	CALL message( 'init_grid', 'PA0280', 1, 2, 0, 6, 0 )
1994	ENDIF
1995	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
1996	tunnel_width_y /= 9999999.9_wp ) THEN
1997	message_string = 'Inconsistent tunnel parameters:' // &
1998	'tunnel can only be oriented' // &
1999	'either in x- or in y-direction.'
2000	CALL message( 'init_grid', 'PA0281', 1, 2, 0, 6, 0 )
2001	ENDIF
2002	!
2003	!-- Tunnel axis along y
2004	IF ( tunnel_width_x /= 9999999.9_wp ) THEN
2005	IF ( tunnel_width_x > ( nx + 1 ) * dx ) THEN
2006	message_string = 'Tunnel width too large'
2007	CALL message( 'init_grid', 'PA0282', 1, 2, 0, 6, 0 )
2008	ENDIF
2009
2010	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_width_x * 0.5_wp )
2011	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_width_x * 0.5_wp )
2012	txs_in = INT( ( nx + 1 ) * 0.5_wp * dx - &
2013	( tunnel_width_x * 0.5_wp - td ) )
2014	txe_in = INT( ( nx + 1 ) * 0.5_wp * dx + &
2015	( tunnel_width_x * 0.5_wp - td ) )
2016
2017	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_length * 0.5_wp )
2018	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_length * 0.5_wp )
2019	tys_in = tys_out
2020	tye_in = tye_out
2021	ENDIF
2022	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
2023	tunnel_width_x - 2.0_wp * td <= 2.0_wp * dx ) &
2024	THEN
2025	message_string = 'Tunnel width too small'
2026	CALL message( 'init_grid', 'PA0175', 1, 2, 0, 6, 0 )
2027	ENDIF
2028	IF ( tunnel_width_y /= 9999999.9_wp .AND. &
2029	tunnel_width_y - 2.0_wp * td <= 2.0_wp * dy ) &
2030	THEN
2031	message_string = 'Tunnel width too small'
2032	CALL message( 'init_grid', 'PA0455', 1, 2, 0, 6, 0 )
2033	ENDIF
2034	!
2035	!-- Tunnel axis along x
2036	IF ( tunnel_width_y /= 9999999.9_wp ) THEN
2037	IF ( tunnel_width_y > ( ny + 1 ) * dy ) THEN
2038	message_string = 'Tunnel width too large'
2039	CALL message( 'init_grid', 'PA0456', 1, 2, 0, 6, 0 )
2040	ENDIF
2041
2042	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_length * 0.5_wp )
2043	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_length * 0.5_wp )
2044	txs_in = txs_out
2045	txe_in = txe_out
2046
2047	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_width_y * 0.5_wp )
2048	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_width_y * 0.5_wp )
2049	tys_in = INT( ( ny + 1 ) * 0.5_wp * dy - &
2050	( tunnel_width_y * 0.5_wp - td ) )
2051	tye_in = INT( ( ny + 1 ) * 0.5_wp * dy + &
2052	( tunnel_width_y * 0.5_wp - td ) )
2053	ENDIF
2054
2055	topo = 0
2056	DO i = nxl, nxr
2057	DO j = nys, nyn
2058	!
2059	!-- Use heaviside function to model outer tunnel surface
2060	hv_out = th * 0.5_wp * &
2061	( ( SIGN( 1.0_wp, i * dx - txs_out ) + 1.0_wp ) &
2062	- ( SIGN( 1.0_wp, i * dx - txe_out ) + 1.0_wp ) )
2063
2064	hv_out = hv_out * 0.5_wp * &
2065	( ( SIGN( 1.0_wp, j * dy - tys_out ) + 1.0_wp ) &
2066	- ( SIGN( 1.0_wp, j * dy - tye_out ) + 1.0_wp ) )
2067	!
2068	!-- Use heaviside function to model inner tunnel surface
2069	hv_in = ( th - td ) * 0.5_wp * &
2070	( ( SIGN( 1.0_wp, i * dx - txs_in ) + 1.0_wp ) &
2071	- ( SIGN( 1.0_wp, i * dx - txe_in ) + 1.0_wp ) )
2072
2073	hv_in = hv_in * 0.5_wp * &
2074	( ( SIGN( 1.0_wp, j * dy - tys_in ) + 1.0_wp ) &
2075	- ( SIGN( 1.0_wp, j * dy - tye_in ) + 1.0_wp ) )
2076	!
2077	!-- Set flags at x-y-positions without any tunnel surface
2078	IF ( hv_out - hv_in == 0.0_wp ) THEN
2079	topo(nzb+1:nzt+1,j,i) = IBSET( topo(nzb+1:nzt+1,j,i), 0 )
2080	!
2081	!-- Set flags at x-y-positions with tunnel surfaces
2082	ELSE
2083	DO k = nzb + 1, nzt + 1
2084	!
2085	!-- Inner tunnel
2086	IF ( hv_out - hv_in == th ) THEN
2087	IF ( zw(k) <= hv_out ) THEN
2088	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
2089	ELSE
2090	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2091	ENDIF
2092	ENDIF
2093	!
2094	!-- Lateral tunnel walls
2095	IF ( hv_out - hv_in == td ) THEN
2096	IF ( zw(k) <= hv_in ) THEN
2097	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2098	ELSEIF ( zw(k) > hv_in .AND. zw(k) <= hv_out ) THEN
2099	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
2100	ELSEIF ( zw(k) > hv_out ) THEN
2101	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2102	ENDIF
2103	ENDIF
2104	ENDDO
2105	ENDIF
2106	ENDDO
2107	ENDDO
2108
2109	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2110	!
2111	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2112	!-- boundary conditions for topography.
2113	IF ( .NOT. bc_ns_cyc ) THEN
2114	IF ( nys == 0 ) THEN
2115	DO i = 1, nbgp
2116	topo(:,nys-i,:) = topo(:,nys,:)
2117	ENDDO
2118	ENDIF
2119	IF ( nyn == ny ) THEN
2120	DO i = 1, nbgp
2121	topo(:,nyn+i,:) = topo(:,nyn,:)
2122	ENDDO
2123	ENDIF
2124	ENDIF
2125	IF ( .NOT. bc_lr_cyc ) THEN
2126	IF ( nxl == 0 ) THEN
2127	DO i = 1, nbgp
2128	topo(:,:,nxl-i) = topo(:,:,nxl)
2129	ENDDO
2130	ENDIF
2131	IF ( nxr == nx ) THEN
2132	DO i = 1, nbgp
2133	topo(:,:,nxr+i) = topo(:,:,nxr)
2134	ENDDO
2135	ENDIF
2136	ENDIF
2137
2138	CASE ( 'read_from_file' )
2139	!
2140	!-- Note, topography information have been already read.
2141	!-- If required, further process topography, i.e. reference buildings on
2142	!-- top of orography and set temporary 3D topography array, which is
2143	!-- used later to set grid flags. Calling of this rouinte is also
2144	!-- required in case of ASCII input, even though no distinction between
2145	!-- terrain- and building height is made in this case.
2146	CALL process_topography( topo )
2147	!
2148	!-- Filter holes resolved by only one grid-point
2149	CALL filter_topography( topo )
2150	!
2151	!-- Exchange ghost-points, as well as add cyclic or Neumann boundary
2152	!-- conditions.
2153	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2154	!
2155	!-- Set lateral boundary conditions for topography on all ghost layers
2156	IF ( .NOT. bc_ns_cyc ) THEN
2157	IF ( nys == 0 ) THEN
2158	DO i = 1, nbgp
2159	topo(:,nys-i,:) = topo(:,nys,:)
2160	ENDDO
2161	ENDIF
2162	IF ( nyn == ny ) THEN
2163	DO i = 1, nbgp
2164	topo(:,nyn+i,:) = topo(:,nyn,:)
2165	ENDDO
2166	ENDIF
2167	ENDIF
2168
2169	IF ( .NOT. bc_lr_cyc ) THEN
2170	IF ( nxl == 0 ) THEN
2171	DO i = 1, nbgp
2172	topo(:,:,nxl-i) = topo(:,:,nxl)
2173	ENDDO
2174	ENDIF
2175	IF ( nxr == nx ) THEN
2176	DO i = 1, nbgp
2177	topo(:,:,nxr+i) = topo(:,:,nxr)
2178	ENDDO
2179	ENDIF
2180	ENDIF
2181
2182
2183	CASE DEFAULT
2184	!
2185	!-- The DEFAULT case is reached either if the parameter topography
2186	!-- contains a wrong character string or if the user has defined a special
2187	!-- case in the user interface. There, the subroutine user_init_grid
2188	!-- checks which of these two conditions applies.
2189	CALL user_init_grid( topo )
2190	CALL filter_topography( topo )
2191
2192	END SELECT
2193	!
2194	!-- Consistency checks and index array initialization are only required for
2195	!-- non-flat topography.
2196	IF ( TRIM( topography ) /= 'flat' ) THEN
2197	!
2198	!-- In case of non-flat topography, check whether the convention how to
2199	!-- define the topography grid has been set correctly, or whether the default
2200	!-- is applicable. If this is not possible, abort.
2201	IF ( TRIM( topography_grid_convention ) == ' ' ) THEN
2202	IF ( TRIM( topography ) /= 'single_building' .AND. &
2203	TRIM( topography ) /= 'single_street_canyon' .AND. &
2204	TRIM( topography ) /= 'tunnel' .AND. &
2205	TRIM( topography ) /= 'read_from_file') THEN
2206	!-- The default value is not applicable here, because it is only valid
2207	!-- for the four standard cases 'single_building',
2208	!-- 'single_street_canyon', 'tunnel' and 'read_from_file'
2209	!-- defined in init_grid.
2210	WRITE( message_string, * ) &
2211	'The value for "topography_grid_convention" ', &
2212	'is not set. Its default value is & only valid for ', &
2213	'"topography" = ''single_building'', ''tunnel'' ', &
2214	'''single_street_canyon'' & or ''read_from_file''.', &
2215	'& Choose ''cell_edge'' or ''cell_center''.'
2216	CALL message( 'init_grid', 'PA0239', 1, 2, 0, 6, 0 )
2217	ELSE
2218	!-- The default value is applicable here.
2219	!-- Set convention according to topography.
2220	IF ( TRIM( topography ) == 'single_building' .OR. &
2221	TRIM( topography ) == 'single_street_canyon' ) THEN
2222	topography_grid_convention = 'cell_edge'
2223	ELSEIF ( TRIM( topography ) == 'read_from_file' .OR. &
2224	TRIM( topography ) == 'tunnel') THEN
2225	topography_grid_convention = 'cell_center'
2226	ENDIF
2227	ENDIF
2228	ELSEIF ( TRIM( topography_grid_convention ) /= 'cell_edge' .AND. &
2229	TRIM( topography_grid_convention ) /= 'cell_center' ) THEN
2230	WRITE( message_string, * ) &
2231	'The value for "topography_grid_convention" is ', &
2232	'not recognized.& Choose ''cell_edge'' or ''cell_center''.'
2233	CALL message( 'init_grid', 'PA0240', 1, 2, 0, 6, 0 )
2234	ENDIF
2235
2236
2237	IF ( topography_grid_convention == 'cell_edge' ) THEN
2238	!
2239	!-- The array nzb_local as defined using the 'cell_edge' convention
2240	!-- describes the actual total size of topography which is defined at the
2241	!-- cell edges where u=0 on the topography walls in x-direction and v=0
2242	!-- on the topography walls in y-direction. However, PALM uses individual
2243	!-- arrays nzb_u\|v\|w\|s_inner\|outer that are based on nzb_s_inner.
2244	!-- Therefore, the extent of topography in nzb_local is now reduced by
2245	!-- 1dx at the E topography walls and by 1dy at the N topography walls
2246	!-- to form the basis for nzb_s_inner.
2247	!-- Note, the reverse memory access (i-j instead of j-i) is absolutely
2248	!-- required at this point.
2249	DO j = nys+1, nyn+1
2250	DO i = nxl-1, nxr
2251	DO k = nzb, nzt+1
2252	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2253	BTEST( topo(k,j,i+1), 0 ) ) &
2254	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2255	ENDDO
2256	ENDDO
2257	ENDDO
2258	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2259
2260	DO i = nxl, nxr+1
2261	DO j = nys-1, nyn
2262	DO k = nzb, nzt+1
2263	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2264	BTEST( topo(k,j+1,i), 0 ) ) &
2265	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2266	ENDDO
2267	ENDDO
2268	ENDDO
2269	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2270
2271	ENDIF
2272	ENDIF
2273
2274
2275	END SUBROUTINE init_topo
2276
2277	SUBROUTINE set_topo_flags(topo)
2278
2279	USE control_parameters, &
2280	ONLY: bc_lr_cyc, bc_ns_cyc, constant_flux_layer, land_surface, &
2281	scalar_advec, topography, use_surface_fluxes, use_top_fluxes, &
2282	urban_surface
2283
2284	USE indices, &
2285	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
2286	nzt, topo_top_ind, wall_flags_0
2287
2288	USE kinds
2289
2290	IMPLICIT NONE
2291
2292	INTEGER(iwp) :: i !< index variable along x
2293	INTEGER(iwp) :: ibit !< integer bit position of topgraphy masking array
2294	INTEGER(iwp) :: j !< index variable along y
2295	INTEGER(iwp) :: k !< index variable along z
2296
2297	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
2298
2299	ALLOCATE( wall_flags_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2300	wall_flags_0 = 0
2301	!
2302	!-- Set-up topography flags. First, set flags only for s, u, v and w-grid.
2303	!-- Further special flags will be set in following loops.
2304	DO i = nxl, nxr
2305	DO j = nys, nyn
2306	DO k = nzb, nzt+1
2307	!
2308	!-- scalar grid
2309	IF ( BTEST( topo(k,j,i), 0 ) ) &
2310	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 0 )
2311	!
2312	!-- u grid
2313	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2314	BTEST( topo(k,j,i-1), 0 ) ) &
2315	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 1 )
2316	!
2317	!-- v grid
2318	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2319	BTEST( topo(k,j-1,i), 0 ) ) &
2320	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 2 )
2321
2322	ENDDO
2323
2324	DO k = nzb, nzt
2325	!
2326	!-- w grid
2327	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2328	BTEST( topo(k+1,j,i), 0 ) ) &
2329	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 3 )
2330	ENDDO
2331	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 3 )
2332
2333	ENDDO
2334	ENDDO
2335
2336	CALL exchange_horiz_int( wall_flags_0, nys, nyn, nxl, nxr, nzt, nbgp )
2337	!
2338	!-- Set outer array for scalars to mask near-surface grid points. Note, on
2339	!-- basis of flag 24 futher flags will be derived which are used to control
2340	!-- production of subgrid TKE production near walls.
2341	DO i = nxl, nxr
2342	DO j = nys, nyn
2343	DO k = nzb, nzt+1
2344	IF ( BTEST( wall_flags_0(k,j-1,i), 0 ) .AND. &
2345	BTEST( wall_flags_0(k,j+1,i), 0 ) .AND. &
2346	BTEST( wall_flags_0(k,j,i-1), 0 ) .AND. &
2347	BTEST( wall_flags_0(k,j,i+1), 0 ) .AND. &
2348	BTEST( wall_flags_0(k,j-1,i-1), 0 ) .AND. &
2349	BTEST( wall_flags_0(k,j+1,i-1), 0 ) .AND. &
2350	BTEST( wall_flags_0(k,j-1,i+1), 0 ) .AND. &
2351	BTEST( wall_flags_0(k,j+1,i+1), 0 ) ) &
2352	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 24 )
2353	ENDDO
2354	ENDDO
2355	ENDDO
2356	!
2357	!-- Set further special flags
2358	DO i = nxl, nxr
2359	DO j = nys, nyn
2360	DO k = nzb, nzt+1
2361	!
2362	!-- scalar grid, former nzb_diff_s_inner.
2363	!-- Note, use this flag also to mask topography in diffusion_u and
2364	!-- diffusion_v along the vertical direction. In case of
2365	!-- use_surface_fluxes, fluxes are calculated via MOST, else, simple
2366	!-- gradient approach is applied. Please note, in case of u- and v-
2367	!-- diffuison, a small error is made at edges (on the east side for u,
2368	!-- at the north side for v), since topography on scalar grid point
2369	!-- is used instead of topography on u/v-grid. As number of topography grid
2370	!-- points on uv-grid is different than s-grid, different number of
2371	!-- surface elements would be required. In order to avoid this,
2372	!-- treat edges (u(k,j,i+1)) simply by a gradient approach, i.e. these
2373	!-- points are not masked within diffusion_u. Tests had shown that the
2374	!-- effect on the flow is negligible.
2375	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2376	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2377	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 8 )
2378	ELSE
2379	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 8 )
2380	ENDIF
2381
2382	ENDDO
2383	!
2384	!-- Special flag to control vertical diffusion at model top - former
2385	!-- nzt_diff
2386	wall_flags_0(:,j,i) = IBSET( wall_flags_0(:,j,i), 9 )
2387	IF ( use_top_fluxes ) &
2388	wall_flags_0(nzt+1,j,i) = IBCLR( wall_flags_0(nzt+1,j,i), 9 )
2389
2390
2391	DO k = nzb+1, nzt
2392	!
2393	!-- Special flag on u grid, former nzb_u_inner + 1, required
2394	!-- for disturb_field and initialization. Do not disturb directly at
2395	!-- topography, as well as initialize u with zero one grid point outside
2396	!-- of topography.
2397	IF ( BTEST( wall_flags_0(k-1,j,i), 1 ) .AND. &
2398	BTEST( wall_flags_0(k,j,i), 1 ) .AND. &
2399	BTEST( wall_flags_0(k+1,j,i), 1 ) ) &
2400	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 20 )
2401	!
2402	!-- Special flag on v grid, former nzb_v_inner + 1, required
2403	!-- for disturb_field and initialization. Do not disturb directly at
2404	!-- topography, as well as initialize v with zero one grid point outside
2405	!-- of topography.
2406	IF ( BTEST( wall_flags_0(k-1,j,i), 2 ) .AND. &
2407	BTEST( wall_flags_0(k,j,i), 2 ) .AND. &
2408	BTEST( wall_flags_0(k+1,j,i), 2 ) ) &
2409	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 21 )
2410	!
2411	!-- Special flag on scalar grid, former nzb_s_inner+1. Used for
2412	!-- lpm_sgs_tke
2413	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2414	BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2415	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2416	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 25 )
2417	!
2418	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2419	!-- in production_e
2420	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2421	IF ( BTEST( wall_flags_0(k,j,i), 24 ) .AND. &
2422	BTEST( wall_flags_0(k-1,j,i), 24 ) .AND. &
2423	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2424	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 29 )
2425	ELSE
2426	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2427	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 29 )
2428	ENDIF
2429	!
2430	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2431	!-- in production_e
2432	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2433	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2434	BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2435	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2436	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 30 )
2437	ELSE
2438	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2439	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 30 )
2440	ENDIF
2441	ENDDO
2442	!
2443	!-- Flags indicating downward facing walls
2444	DO k = nzb+1, nzt
2445	!
2446	!-- Scalar grid
2447	IF ( BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2448	.NOT. BTEST( wall_flags_0(k,j,i), 0 ) ) &
2449	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 13 )
2450	!
2451	!-- Downward facing wall on u grid
2452	IF ( BTEST( wall_flags_0(k-1,j,i), 1 ) .AND. &
2453	.NOT. BTEST( wall_flags_0(k,j,i), 1 ) ) &
2454	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 15 )
2455	!
2456	!-- Downward facing wall on v grid
2457	IF ( BTEST( wall_flags_0(k-1,j,i), 2 ) .AND. &
2458	.NOT. BTEST( wall_flags_0(k,j,i), 2 ) ) &
2459	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 17 )
2460	!
2461	!-- Downward facing wall on w grid
2462	IF ( BTEST( wall_flags_0(k-1,j,i), 3 ) .AND. &
2463	.NOT. BTEST( wall_flags_0(k,j,i), 3 ) ) &
2464	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 19 )
2465	ENDDO
2466	!
2467	!-- Flags indicating upward facing walls
2468	DO k = nzb, nzt
2469	!
2470	!-- Upward facing wall on scalar grid
2471	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2472	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2473	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 12 )
2474	!
2475	!-- Upward facing wall on u grid
2476	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 1 ) .AND. &
2477	BTEST( wall_flags_0(k+1,j,i), 1 ) ) &
2478	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 14 )
2479
2480	!
2481	!-- Upward facing wall on v grid
2482	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 2 ) .AND. &
2483	BTEST( wall_flags_0(k+1,j,i), 2 ) ) &
2484	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 16 )
2485
2486	!
2487	!-- Upward facing wall on w grid
2488	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 3 ) .AND. &
2489	BTEST( wall_flags_0(k+1,j,i), 3 ) ) &
2490	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 18 )
2491	!
2492	!-- Special flag on scalar grid, former nzb_s_inner
2493	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .OR. &
2494	BTEST( wall_flags_0(k,j,i), 12 ) .OR. &
2495	BTEST( wall_flags_0(k,j,i), 13 ) ) &
2496	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 22 )
2497	!
2498	!-- Special flag on scalar grid, nzb_diff_s_inner - 1, required for
2499	!-- flow_statistics
2500	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2501	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2502	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2503	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 23 )
2504	ELSE
2505	IF ( BTEST( wall_flags_0(k,j,i), 22 ) ) &
2506	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 23 )
2507	ENDIF
2508
2509
2510	ENDDO
2511	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 22 )
2512	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 23 )
2513	!
2514	!-- Set flags indicating that topography is close by in horizontal
2515	!-- direction, i.e. flags that infold the topography. These will be used
2516	!-- to set advection flags for passive scalars, where due to large
2517	!-- gradients near buildings stationary numerical oscillations can produce
2518	!-- unrealistically high concentrations. This is only necessary if
2519	!-- WS-scheme is applied for scalar advection. Note, these flags will be
2520	!-- only used for passive scalars such as chemical species or aerosols.
2521	IF ( scalar_advec == 'ws-scheme' ) THEN
2522	DO k = nzb, nzt
2523	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. ( &
2524	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-1), 0 ) ) .OR.&
2525	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-2), 0 ) ) .OR.&
2526	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-3), 0 ) ) .OR.&
2527	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+1), 0 ) ) .OR.&
2528	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+2), 0 ) ) .OR.&
2529	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+3), 0 ) ) .OR.&
2530	ANY( .NOT. BTEST( wall_flags_0(k,j-1,i-3:i+3), 0 ) ) .OR.&
2531	ANY( .NOT. BTEST( wall_flags_0(k,j-2,i-3:i+3), 0 ) ) .OR.&
2532	ANY( .NOT. BTEST( wall_flags_0(k,j-3,i-3:i+3), 0 ) ) .OR.&
2533	ANY( .NOT. BTEST( wall_flags_0(k,j+1,i-3:i+3), 0 ) ) .OR.&
2534	ANY( .NOT. BTEST( wall_flags_0(k,j+2,i-3:i+3), 0 ) ) .OR.&
2535	ANY( .NOT. BTEST( wall_flags_0(k,j+3,i-3:i+3), 0 ) ) &
2536	) ) &
2537	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 31 )
2538
2539	ENDDO
2540	ENDIF
2541	ENDDO
2542	ENDDO
2543	!
2544	!-- Finally, set identification flags indicating natural terrain or buildings.
2545	!-- Natural terrain grid points. Information on the type of the surface is
2546	!-- stored in bit 1 of 3D Integer array topo. However, this bit is only set
2547	!-- when topography is read from file. In order to run the land-surface model
2548	!-- also without topography information, set bit 1 explicitely in this case.
2549	IF ( land_surface ) THEN
2550	!
2551	!-- If no topography is initialized, the land-surface is at k = nzb.
2552	IF ( TRIM( topography ) /= 'read_from_file' ) THEN
2553	wall_flags_0(nzb,:,:) = IBSET( wall_flags_0(nzb,:,:), 5 )
2554	ELSE
2555	DO i = nxl, nxr
2556	DO j = nys, nyn
2557	DO k = nzb, nzt+1
2558	!
2559	!-- Natural terrain grid point
2560	IF ( BTEST( topo(k,j,i), 1 ) ) &
2561	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 5 )
2562	ENDDO
2563	ENDDO
2564	ENDDO
2565	ENDIF
2566	ENDIF
2567	!
2568	!-- Building grid points.
2569	IF ( urban_surface ) THEN
2570	DO i = nxl, nxr
2571	DO j = nys, nyn
2572	DO k = nzb, nzt+1
2573	IF ( BTEST( topo(k,j,i), 2 ) ) &
2574	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 6 )
2575	ENDDO
2576	ENDDO
2577	ENDDO
2578	ENDIF
2579	!
2580	!-- Exchange ghost points for wall flags
2581	CALL exchange_horiz_int( wall_flags_0, nys, nyn, nxl, nxr, nzt, nbgp )
2582	!
2583	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2584	!-- boundary conditions for topography.
2585	IF ( .NOT. bc_ns_cyc ) THEN
2586	IF ( nys == 0 ) THEN
2587	DO i = 1, nbgp
2588	wall_flags_0(:,nys-i,:) = wall_flags_0(:,nys,:)
2589	ENDDO
2590	ENDIF
2591	IF ( nyn == ny ) THEN
2592	DO i = 1, nbgp
2593	wall_flags_0(:,nyn+i,:) = wall_flags_0(:,nyn,:)
2594	ENDDO
2595	ENDIF
2596	ENDIF
2597	IF ( .NOT. bc_lr_cyc ) THEN
2598	IF ( nxl == 0 ) THEN
2599	DO i = 1, nbgp
2600	wall_flags_0(:,:,nxl-i) = wall_flags_0(:,:,nxl)
2601	ENDDO
2602	ENDIF
2603	IF ( nxr == nx ) THEN
2604	DO i = 1, nbgp
2605	wall_flags_0(:,:,nxr+i) = wall_flags_0(:,:,nxr)
2606	ENDDO
2607	ENDIF
2608	ENDIF
2609	!
2610	!-- Pre-calculate topography top indices (former get_topography_top_index
2611	!-- function)
2612	ALLOCATE( topo_top_ind(nysg:nyng,nxlg:nxrg,0:4) )
2613	!
2614	!-- Uppermost topography index on scalar grid
2615	ibit = 12
2616	topo_top_ind(:,:,0) = MAXLOC( &
2617	MERGE( 1, 0, &
2618	BTEST( wall_flags_0(:,:,:), ibit ) &
2619	), DIM = 1 &
2620	) - 1
2621	!
2622	!-- Uppermost topography index on u grid
2623	ibit = 14
2624	topo_top_ind(:,:,1) = MAXLOC( &
2625	MERGE( 1, 0, &
2626	BTEST( wall_flags_0(:,:,:), ibit ) &
2627	), DIM = 1 &
2628	) - 1
2629	!
2630	!-- Uppermost topography index on v grid
2631	ibit = 16
2632	topo_top_ind(:,:,2) = MAXLOC( &
2633	MERGE( 1, 0, &
2634	BTEST( wall_flags_0(:,:,:), ibit ) &
2635	), DIM = 1 &
2636	) - 1
2637	!
2638	!-- Uppermost topography index on w grid
2639	ibit = 18
2640	topo_top_ind(:,:,3) = MAXLOC( &
2641	MERGE( 1, 0, &
2642	BTEST( wall_flags_0(:,:,:), ibit ) &
2643	), DIM = 1 &
2644	) - 1
2645	!
2646	!-- Uppermost topography index on scalar outer grid
2647	ibit = 24
2648	topo_top_ind(:,:,4) = MAXLOC( &
2649	MERGE( 1, 0, &
2650	BTEST( wall_flags_0(:,:,:), ibit ) &
2651	), DIM = 1 &
2652	) - 1
2653
2654	END SUBROUTINE set_topo_flags
2655
2656
2657

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