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source: palm/trunk/SOURCE/init_grid.f90 @ 4328

Last change on this file since 4328 was 4328, checked in by suehring, 5 years ago
Minor change in nzb_max computation; commentation added; minor formatting adjustments in advec_ws
Property svn:keywords set to `Id`
File size: 119.4 KB

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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 4328 2019-12-09 18:53:04Z suehring $
27	! Minor change in nzb_max computation. Commentation added.
28	!
29	! 4314 2019-11-29 10:29:20Z suehring
30	! Set additional topography flag 4 to mark topography grid points emerged
31	! from the filtering process.
32	!
33	! 4294 2019-11-13 18:34:16Z suehring
34	! Bugfix, always set bit 5 and 6 of wall_flags, indicating terrain- and
35	! building surfaces in all cases, in order to enable terrain-following output
36	! also when no land- or urban-surface model is applied.
37	!
38	! 4265 2019-10-15 16:16:24Z suehring
39	! Bugfix for last commit, exchange oro_max variable only when it is allocated
40	! (not necessarily the case when topography is input from ASCII file).
41	!
42	! 4245 2019-09-30 08:40:37Z pavelkrc
43	! Store oro_max (building z-offset) in 2D for building surfaces
44	!
45	! 4189 2019-08-26 16:19:38Z suehring
46	! - Add check for proper setting of namelist parameter topography
47	! - Set flag to indicate land surfaces in case no topography is provided
48	!
49	! 4182 2019-08-22 15:20:23Z scharf
50	! Corrected "Former revisions" section
51	!
52	! 4168 2019-08-16 13:50:17Z suehring
53	! Pre-calculate topography top index and store it on an array (replaces former
54	! functions get_topography_top_index)
55	!
56	! 4159 2019-08-15 13:31:35Z suehring
57	! Revision of topography processing. This was not consistent between 2D and 3D
58	! buildings.
59	!
60	! 4144 2019-08-06 09:11:47Z raasch
61	! relational operators .EQ., .NE., etc. replaced by ==, /=, etc.
62	!
63	! 4115 2019-07-24 12:50:49Z suehring
64	! Bugfix in setting near-surface flag 24, inidicating wall-bounded grid points
65	!
66	! 4110 2019-07-22 17:05:21Z suehring
67	! - Separate initialization of advection flags for momentum and scalars.
68	! - Change subroutine interface for ws_init_flags_scalar to pass boundary flags
69	!
70	! 4109 2019-07-22 17:00:34Z suehring
71	! Fix bad commit
72	!
73	! 3926 2019-04-23 12:56:42Z suehring
74	! Minor bugfix in building mapping when all building IDs in the model domain
75	! are missing
76	!
77	! 3857 2019-04-03 13:00:16Z knoop
78	! In projection of non-building 3D objects onto numerical grid remove
79	! dependency on building_type
80	!
81	! 3763 2019-02-25 17:33:49Z suehring
82	! Replace work-around for ghost point exchange of 1-byte arrays with specific
83	! routine as already done in other routines
84	!
85	! 3761 2019-02-25 15:31:42Z raasch
86	! unused variables removed
87	!
88	! 3661 2019-01-08 18:22:50Z suehring
89	! Remove setting of nzb_max to nzt at non-cyclic boundary PEs, instead,
90	! order degradation of advection scheme is handeled directly in advec_ws
91	!
92	! 3655 2019-01-07 16:51:22Z knoop
93	! Comment added
94	!
95	! Revision 1.1 1997/08/11 06:17:45 raasch
96	! Initial revision (Testversion)
97	!
98	!
99	! Description:
100	! -----------------------------------------------------------------------------!
101	!> Creating grid depending constants
102	!> @todo: Rearrange topo flag list
103	!> @todo: reference 3D buildings on top of orography is not tested and may need
104	!> further improvement for steep slopes
105	!> @todo: Use more advanced setting of building type at filled holes
106	!------------------------------------------------------------------------------!
107	SUBROUTINE init_grid
108
109	USE advec_ws, &
110	ONLY: ws_init_flags_momentum, ws_init_flags_scalar
111
112	USE arrays_3d, &
113	ONLY: dd2zu, ddzu, ddzu_pres, ddzw, dzu, dzw, x, xu, y, yv, zu, zw
114
115	USE control_parameters, &
116	ONLY: bc_lr_cyc, bc_ns_cyc, &
117	bc_dirichlet_l, &
118	bc_dirichlet_n, &
119	bc_dirichlet_r, &
120	bc_dirichlet_s, &
121	bc_radiation_l, &
122	bc_radiation_n, &
123	bc_radiation_r, &
124	bc_radiation_s, &
125	constant_flux_layer, dz, dz_max, dz_stretch_factor, &
126	dz_stretch_factor_array, dz_stretch_level, dz_stretch_level_end,&
127	dz_stretch_level_end_index, dz_stretch_level_start_index, &
128	dz_stretch_level_start, ibc_uv_b, message_string, &
129	momentum_advec, number_stretch_level_end, &
130	number_stretch_level_start, ocean_mode, psolver, scalar_advec, &
131	topography, use_surface_fluxes
132
133	USE grid_variables, &
134	ONLY: ddx, ddx2, ddy, ddy2, dx, dx2, dy, dy2, zu_s_inner, zw_w_inner
135
136	USE indices, &
137	ONLY: advc_flags_m, &
138	advc_flags_s, &
139	nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
140	nzb, nzb_diff, nzb_diff_s_inner, nzb_diff_s_outer, &
141	nzb_max, nzb_s_inner, nzb_s_outer, nzb_u_inner, &
142	nzb_u_outer, nzb_v_inner, nzb_v_outer, nzb_w_inner, &
143	nzb_w_outer, nzt, topo_top_ind, topo_min_level
144
145	USE kinds
146
147	USE pegrid
148
149	USE poismg_noopt_mod
150
151	USE surface_mod, &
152	ONLY: init_bc
153
154	USE vertical_nesting_mod, &
155	ONLY: vnested, vnest_init_grid
156
157	IMPLICIT NONE
158
159	INTEGER(iwp) :: i !< index variable along x
160	INTEGER(iwp) :: j !< index variable along y
161	INTEGER(iwp) :: k !< index variable along z
162	INTEGER(iwp) :: k_top !< topography top index on local PE
163	INTEGER(iwp) :: n !< loop variable for stretching
164	INTEGER(iwp) :: number_dz !< number of user-specified dz values
165	INTEGER(iwp) :: nzb_local_max !< vertical grid index of maximum topography height
166	INTEGER(iwp) :: nzb_local_min !< vertical grid index of minimum topography height
167
168	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
169	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_tmp !< dummy to calculate topography indices on u- and v-grid
170
171	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
172
173	REAL(wp) :: dz_level_end !< distance between calculated height level for u/v-grid and user-specified end level for stretching
174	REAL(wp) :: dz_stretched !< stretched vertical grid spacing
175
176	REAL(wp), DIMENSION(:), ALLOCATABLE :: min_dz_stretch_level_end !< Array that contains all minimum heights where the stretching can end
177
178
179	!
180	!-- Calculation of horizontal array bounds including ghost layers
181	nxlg = nxl - nbgp
182	nxrg = nxr + nbgp
183	nysg = nys - nbgp
184	nyng = nyn + nbgp
185
186	!
187	!-- Allocate grid arrays
188	ALLOCATE( x(0:nx), xu(0:nx) )
189	DO i = 0, nx
190	xu(i) = i * dx
191	x(i) = i * dx + 0.5_wp * dx
192	ENDDO
193
194	ALLOCATE( y(0:ny), yv(0:ny) )
195	DO j = 0, ny
196	yv(j) = j * dy
197	y(j) = j * dy + 0.5_wp * dy
198	ENDDO
199
200	!
201	!-- Allocate grid arrays
202	ALLOCATE( ddzu(1:nzt+1), ddzw(1:nzt+1), dd2zu(1:nzt), dzu(1:nzt+1), &
203	dzw(1:nzt+1), zu(nzb:nzt+1), zw(nzb:nzt+1) )
204
205	!
206	!-- Compute height of u-levels from constant grid length and dz stretch factors
207	IF ( dz(1) == -1.0_wp ) THEN
208	message_string = 'missing dz'
209	CALL message( 'init_grid', 'PA0200', 1, 2, 0, 6, 0 )
210	ELSEIF ( dz(1) <= 0.0_wp ) THEN
211	WRITE( message_string, * ) 'dz=',dz(1),' <= 0.0'
212	CALL message( 'init_grid', 'PA0201', 1, 2, 0, 6, 0 )
213	ENDIF
214
215	!
216	!-- Initialize dz_stretch_level_start with the value of dz_stretch_level
217	!-- if it was set by the user
218	IF ( dz_stretch_level /= -9999999.9_wp ) THEN
219	dz_stretch_level_start(1) = dz_stretch_level
220	ENDIF
221
222	!
223	!-- Determine number of dz values and stretching levels specified by the
224	!-- user to allow right controlling of the stretching mechanism and to
225	!-- perform error checks. The additional requirement that dz /= dz_max
226	!-- for counting number of user-specified dz values is necessary. Otherwise
227	!-- restarts would abort if the old stretching mechanism with dz_stretch_level
228	!-- is used (Attention: The user is not allowed to specify a dz value equal
229	!-- to the default of dz_max = 999.0).
230	number_dz = COUNT( dz /= -1.0_wp .AND. dz /= dz_max)
231	number_stretch_level_start = COUNT( dz_stretch_level_start /= &
232	-9999999.9_wp )
233	number_stretch_level_end = COUNT( dz_stretch_level_end /= &
234	9999999.9_wp )
235
236	!
237	!-- The number of specified end levels +1 has to be the same than the number
238	!-- of specified dz values
239	IF ( number_dz /= number_stretch_level_end + 1 ) THEN
240	WRITE( message_string, * ) 'The number of values for dz = ', &
241	number_dz, 'has to be the same than& ', &
242	'the number of values for ', &
243	'dz_stretch_level_end + 1 = ', &
244	number_stretch_level_end+1
245	CALL message( 'init_grid', 'PA0156', 1, 2, 0, 6, 0 )
246	ENDIF
247
248	!
249	!-- The number of specified start levels has to be the same or one less than
250	!-- the number of specified dz values
251	IF ( number_dz /= number_stretch_level_start + 1 .AND. &
252	number_dz /= number_stretch_level_start ) THEN
253	WRITE( message_string, * ) 'The number of values for dz = ', &
254	number_dz, 'has to be the same or one ', &
255	'more than& the number of values for ', &
256	'dz_stretch_level_start = ', &
257	number_stretch_level_start
258	CALL message( 'init_grid', 'PA0211', 1, 2, 0, 6, 0 )
259	ENDIF
260
261	!-- The number of specified start levels has to be the same or one more than
262	!-- the number of specified end levels
263	IF ( number_stretch_level_start /= number_stretch_level_end + 1 .AND. &
264	number_stretch_level_start /= number_stretch_level_end ) THEN
265	WRITE( message_string, * ) 'The number of values for ', &
266	'dz_stretch_level_start = ', &
267	dz_stretch_level_start, 'has to be the ',&
268	'same or one more than& the number of ', &
269	'values for dz_stretch_level_end = ', &
270	number_stretch_level_end
271	CALL message( 'init_grid', 'PA0216', 1, 2, 0, 6, 0 )
272	ENDIF
273
274	!
275	!-- Initialize dz for the free atmosphere with the value of dz_max
276	IF ( dz(number_stretch_level_start+1) == -1.0_wp .AND. &
277	number_stretch_level_start /= 0 ) THEN
278	dz(number_stretch_level_start+1) = dz_max
279	ENDIF
280
281	!
282	!-- Initialize the stretching factor if (infinitely) stretching in the free
283	!-- atmosphere is desired (dz_stretch_level_end was not specified for the
284	!-- free atmosphere)
285	IF ( number_stretch_level_start == number_stretch_level_end + 1 ) THEN
286	dz_stretch_factor_array(number_stretch_level_start) = &
287	dz_stretch_factor
288	ENDIF
289
290	!
291	!-- Allocation of arrays for stretching
292	ALLOCATE( min_dz_stretch_level_end(number_stretch_level_start) )
293
294	!
295	!-- Define the vertical grid levels
296	IF ( .NOT. ocean_mode ) THEN
297
298	!
299	!-- The stretching region has to be large enough to allow for a smooth
300	!-- transition between two different grid spacings
301	DO n = 1, number_stretch_level_start
302	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) + &
303	4 * MAX( dz(n),dz(n+1) )
304	ENDDO
305
306	IF ( ANY( min_dz_stretch_level_end(1:number_stretch_level_start) > &
307	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
308	message_string= 'Eeach dz_stretch_level_end has to be larger ' // &
309	'than its corresponding value for &' // &
310	'dz_stretch_level_start + 4*MAX(dz(n),dz(n+1)) '//&
311	'to allow for smooth grid stretching'
312	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
313	ENDIF
314
315	!
316	!-- Stretching must not be applied within the prandtl_layer
317	!-- (first two grid points). For the default case dz_stretch_level_start
318	!-- is negative. Therefore the absolut value is checked here.
319	IF ( ANY( ABS( dz_stretch_level_start ) < dz(1) * 1.5_wp ) ) THEN
320	WRITE( message_string, * ) 'Eeach dz_stretch_level_start has to be ',&
321	'larger than ', dz(1) * 1.5
322	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
323	ENDIF
324
325	!
326	!-- The stretching has to start and end on a grid level. Therefore
327	!-- user-specified values have to ''interpolate'' to the next lowest level
328	IF ( number_stretch_level_start /= 0 ) THEN
329	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) - &
330	dz(1)/2.0) / dz(1) ) &
331	* dz(1) + dz(1)/2.0
332	ENDIF
333
334	IF ( number_stretch_level_start > 1 ) THEN
335	DO n = 2, number_stretch_level_start
336	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
337	dz(n) ) * dz(n)
338	ENDDO
339	ENDIF
340
341	IF ( number_stretch_level_end /= 0 ) THEN
342	DO n = 1, number_stretch_level_end
343	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
344	dz(n+1) ) * dz(n+1)
345	ENDDO
346	ENDIF
347
348	!
349	!-- Determine stretching factor if necessary
350	IF ( number_stretch_level_end >= 1 ) THEN
351	CALL calculate_stretching_factor( number_stretch_level_end )
352	ENDIF
353
354	!
355	!-- Grid for atmosphere with surface at z=0 (k=0, w-grid).
356	!-- First compute the u- and v-levels. In case of dirichlet bc for u and v
357	!-- the first u/v- and w-level (k=0) are defined at same height (z=0).
358	!-- The second u-level (k=1) corresponds to the top of the
359	!-- Prandtl-layer.
360	IF ( ibc_uv_b == 0 .OR. ibc_uv_b == 2 ) THEN
361	zu(0) = 0.0_wp
362	ELSE
363	zu(0) = - dz(1) * 0.5_wp
364	ENDIF
365
366	zu(1) = dz(1) * 0.5_wp
367
368	!
369	!-- Determine u and v height levels considering the possibility of grid
370	!-- stretching in several heights.
371	n = 1
372	dz_stretch_level_start_index = nzt+1
373	dz_stretch_level_end_index = nzt+1
374	dz_stretched = dz(1)
375
376	!-- The default value of dz_stretch_level_start is negative, thus the first
377	!-- condition is always true. Hence, the second condition is necessary.
378	DO k = 2, nzt+1
379	IF ( dz_stretch_level_start(n) <= zu(k-1) .AND. &
380	dz_stretch_level_start(n) /= -9999999.9_wp ) THEN
381	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
382
383	IF ( dz(n) > dz(n+1) ) THEN
384	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
385	ELSE
386	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
387	ENDIF
388
389	IF ( dz_stretch_level_start_index(n) == nzt+1 ) &
390	dz_stretch_level_start_index(n) = k-1
391
392	ENDIF
393
394	zu(k) = zu(k-1) + dz_stretched
395
396	!
397	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
398	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
399
400	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
401	zu(k) = dz_stretch_level_end(n)
402	dz_stretched = dz(n+1)
403	dz_stretch_level_end_index(n) = k
404	n = n + 1
405	ENDIF
406	ENDDO
407
408	!
409	!-- Compute the w-levels. They are always staggered half-way between the
410	!-- corresponding u-levels. In case of dirichlet bc for u and v at the
411	!-- ground the first u- and w-level (k=0) are defined at same height (z=0).
412	!-- The top w-level is extrapolated linearly.
413	zw(0) = 0.0_wp
414	DO k = 1, nzt
415	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
416	ENDDO
417	zw(nzt+1) = zw(nzt) + 2.0_wp * ( zu(nzt+1) - zw(nzt) )
418
419	ELSE
420
421	!
422	!-- The stretching region has to be large enough to allow for a smooth
423	!-- transition between two different grid spacings
424	DO n = 1, number_stretch_level_start
425	min_dz_stretch_level_end(n) = dz_stretch_level_start(n) - &
426	4 * MAX( dz(n),dz(n+1) )
427	ENDDO
428
429	IF ( ANY( min_dz_stretch_level_end (1:number_stretch_level_start) < &
430	dz_stretch_level_end(1:number_stretch_level_start) ) ) THEN
431	message_string= 'Eeach dz_stretch_level_end has to be less ' // &
432	'than its corresponding value for &' // &
433	'dz_stretch_level_start - 4*MAX(dz(n),dz(n+1)) '//&
434	'to allow for smooth grid stretching'
435	CALL message( 'init_grid', 'PA0224', 1, 2, 0, 6, 0 )
436	ENDIF
437
438	!
439	!-- Stretching must not be applied close to the surface (last two grid
440	!-- points). For the default case dz_stretch_level_start is negative.
441	IF ( ANY( dz_stretch_level_start > - dz(1) * 1.5_wp ) ) THEN
442	WRITE( message_string, * ) 'Eeach dz_stretch_level_start has to be ',&
443	'less than ', dz(1) * 1.5
444	CALL message( 'init_grid', 'PA0226', 1, 2, 0, 6, 0 )
445	ENDIF
446
447	!
448	!-- The stretching has to start and end on a grid level. Therefore
449	!-- user-specified values have to ''interpolate'' to the next highest level
450	IF ( number_stretch_level_start /= 0 ) THEN
451	dz_stretch_level_start(1) = INT( (dz_stretch_level_start(1) + &
452	dz(1)/2.0) / dz(1) ) &
453	* dz(1) - dz(1)/2.0
454	ENDIF
455
456	IF ( number_stretch_level_start > 1 ) THEN
457	DO n = 2, number_stretch_level_start
458	dz_stretch_level_start(n) = INT( dz_stretch_level_start(n) / &
459	dz(n) ) * dz(n)
460	ENDDO
461	ENDIF
462
463	IF ( number_stretch_level_end /= 0 ) THEN
464	DO n = 1, number_stretch_level_end
465	dz_stretch_level_end(n) = INT( dz_stretch_level_end(n) / &
466	dz(n+1) ) * dz(n+1)
467	ENDDO
468	ENDIF
469
470	!
471	!-- Determine stretching factor if necessary
472	IF ( number_stretch_level_end >= 1 ) THEN
473	CALL calculate_stretching_factor( number_stretch_level_end )
474	ENDIF
475
476	!
477	!-- Grid for ocean with free water surface is at k=nzt (w-grid).
478	!-- In case of neumann bc at the ground the first first u-level (k=0) lies
479	!-- below the first w-level (k=0). In case of dirichlet bc the first u- and
480	!-- w-level are defined at same height, but staggered from the second level.
481	!-- The second u-level (k=1) corresponds to the top of the Prandtl-layer.
482	!-- z values are negative starting from z=0 (surface)
483	zu(nzt+1) = dz(1) * 0.5_wp
484	zu(nzt) = - dz(1) * 0.5_wp
485
486	!
487	!-- Determine u and v height levels considering the possibility of grid
488	!-- stretching in several heights.
489	n = 1
490	dz_stretch_level_start_index = 0
491	dz_stretch_level_end_index = 0
492	dz_stretched = dz(1)
493
494	DO k = nzt-1, 0, -1
495
496	IF ( dz_stretch_level_start(n) >= zu(k+1) ) THEN
497	dz_stretched = dz_stretched * dz_stretch_factor_array(n)
498
499	IF ( dz(n) > dz(n+1) ) THEN
500	dz_stretched = MAX( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (higher) dz
501	ELSE
502	dz_stretched = MIN( dz_stretched, dz(n+1) ) !Restrict dz_stretched to the user-specified (lower) dz
503	ENDIF
504
505	IF ( dz_stretch_level_start_index(n) == 0 ) &
506	dz_stretch_level_start_index(n) = k+1
507
508	ENDIF
509
510	zu(k) = zu(k+1) - dz_stretched
511
512	!
513	!-- Make sure that the stretching ends exactly at dz_stretch_level_end
514	dz_level_end = ABS( zu(k) - dz_stretch_level_end(n) )
515
516	IF ( dz_level_end < dz(n+1)/3.0 ) THEN
517	zu(k) = dz_stretch_level_end(n)
518	dz_stretched = dz(n+1)
519	dz_stretch_level_end_index(n) = k
520	n = n + 1
521	ENDIF
522	ENDDO
523
524	!
525	!-- Compute the w-levels. They are always staggered half-way between the
526	!-- corresponding u-levels, except in case of dirichlet bc for u and v
527	!-- at the ground. In this case the first u- and w-level are defined at
528	!-- same height. The top w-level (nzt+1) is not used but set for
529	!-- consistency, since w and all scalar variables are defined up tp nzt+1.
530	zw(nzt+1) = dz(1)
531	zw(nzt) = 0.0_wp
532	DO k = 0, nzt
533	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
534	ENDDO
535
536	!
537	!-- In case of dirichlet bc for u and v the first u- and w-level are defined
538	!-- at same height.
539	IF ( ibc_uv_b == 0 ) THEN
540	zu(0) = zw(0)
541	ENDIF
542
543	ENDIF
544
545	!
546	!-- Compute grid lengths.
547	DO k = 1, nzt+1
548	dzu(k) = zu(k) - zu(k-1)
549	ddzu(k) = 1.0_wp / dzu(k)
550	dzw(k) = zw(k) - zw(k-1)
551	ddzw(k) = 1.0_wp / dzw(k)
552	ENDDO
553
554	DO k = 1, nzt
555	dd2zu(k) = 1.0_wp / ( dzu(k) + dzu(k+1) )
556	ENDDO
557
558	!
559	!-- The FFT- SOR-pressure solvers assume grid spacings of a staggered grid
560	!-- everywhere. For the actual grid, the grid spacing at the lowest level
561	!-- is only dz/2, but should be dz. Therefore, an additional array
562	!-- containing with appropriate grid information is created for these
563	!-- solvers.
564	IF ( psolver(1:9) /= 'multigrid' ) THEN
565	ALLOCATE( ddzu_pres(1:nzt+1) )
566	ddzu_pres = ddzu
567	ddzu_pres(1) = ddzu_pres(2) ! change for lowest level
568	ENDIF
569
570	!
571	!-- Compute the reciprocal values of the horizontal grid lengths.
572	ddx = 1.0_wp / dx
573	ddy = 1.0_wp / dy
574	dx2 = dx * dx
575	dy2 = dy * dy
576	ddx2 = 1.0_wp / dx2
577	ddy2 = 1.0_wp / dy2
578
579	!
580	!-- Allocate 3D array to set topography
581	ALLOCATE( topo(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
582	topo = 0
583	!
584	!-- Initialize topography by generic topography or read from topography from file.
585	CALL init_topo( topo )
586	!
587	!-- Set flags to mask topography on the grid.
588	CALL set_topo_flags( topo )
589	!
590	!-- Calculate wall flag arrays for the multigrid method.
591	!-- Please note, wall flags are only applied in the non-optimized version.
592	IF ( psolver == 'multigrid_noopt' ) CALL poismg_noopt_init
593
594	!
595	!-- Init flags for ws-scheme to degrade order of the numerics near walls, i.e.
596	!-- to decrease the numerical stencil appropriately. The order of the scheme
597	!-- is degraded near solid walls as well as near non-cyclic inflow and outflow
598	!-- boundaries. Do this separately for momentum and scalars.
599	IF ( momentum_advec == 'ws-scheme' ) THEN
600	ALLOCATE( advc_flags_m(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
601	CALL ws_init_flags_momentum
602	ENDIF
603	IF ( scalar_advec == 'ws-scheme' ) THEN
604	ALLOCATE( advc_flags_s(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
605	advc_flags_s = 0
606
607	CALL ws_init_flags_scalar( bc_dirichlet_l .OR. bc_radiation_l, &
608	bc_dirichlet_n .OR. bc_radiation_n, &
609	bc_dirichlet_r .OR. bc_radiation_r, &
610	bc_dirichlet_s .OR. bc_radiation_s, &
611	advc_flags_s )
612	ENDIF
613
614	!
615	!-- Determine the maximum level of topography. It is used for
616	!-- steering the degradation of order of the applied advection scheme,
617	!-- as well in the lpm.
618	k_top = 0
619	DO i = nxl, nxr
620	DO j = nys, nyn
621	DO k = nzb, nzt + 1
622	k_top = MAX( k_top, MERGE( k, 0, .NOT. BTEST( topo(k,j,i), 0 ) ) )
623	ENDDO
624	ENDDO
625	ENDDO
626	#if defined( __parallel )
627	CALL MPI_ALLREDUCE( k_top, nzb_max, 1, MPI_INTEGER, &
628	MPI_MAX, comm2d, ierr )
629	#else
630	nzb_max = k_top
631	#endif
632	!
633	!-- Increment nzb_max by 1 in order to allow for proper diverengence correction.
634	!-- Further, in case topography extents up to the model top, limit to nzt.
635	nzb_max = MIN( nzb_max+1, nzt )
636	!
637	!-- Determine minimum index of topography. Usually, this will be nzb. In case
638	!-- there is elevated topography, however, the lowest topography will be higher.
639	!-- This index is e.g. used to calculate mean first-grid point atmosphere
640	!-- temperature, surface pressure and density, etc. .
641	topo_min_level = 0
642	#if defined( __parallel )
643	CALL MPI_ALLREDUCE( MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
644	topo_min_level, 1, MPI_INTEGER, MPI_MIN, comm2d, ierr )
645	#else
646	topo_min_level = MINVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
647	#endif
648	!
649	!-- Initialize boundary conditions via surface type
650	CALL init_bc
651
652	!
653	!-- Allocate and set topography height arrays required for data output
654	IF ( TRIM( topography ) /= 'flat' ) THEN
655	!
656	!-- Allocate and set the arrays containing the topography height
657	IF ( nxr == nx .AND. nyn /= ny ) THEN
658	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn), &
659	zw_w_inner(nxl:nxr+1,nys:nyn) )
660	ELSEIF ( nxr /= nx .AND. nyn == ny ) THEN
661	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn+1), &
662	zw_w_inner(nxl:nxr,nys:nyn+1) )
663	ELSEIF ( nxr == nx .AND. nyn == ny ) THEN
664	ALLOCATE( zu_s_inner(nxl:nxr+1,nys:nyn+1), &
665	zw_w_inner(nxl:nxr+1,nys:nyn+1) )
666	ELSE
667	ALLOCATE( zu_s_inner(nxl:nxr,nys:nyn), &
668	zw_w_inner(nxl:nxr,nys:nyn) )
669	ENDIF
670
671	zu_s_inner = 0.0_wp
672	zw_w_inner = 0.0_wp
673	!
674	!-- Determine local topography height on scalar and w-grid. Note, setting
675	!-- lateral boundary values is not necessary, realized via wall_flags_0
676	!-- array. Further, please note that loop bounds are different from
677	!-- nxl to nxr and nys to nyn on south and right model boundary, hence,
678	!-- use intrinsic lbound and ubound functions to infer array bounds.
679	DO i = LBOUND(zu_s_inner, 1), UBOUND(zu_s_inner, 1)
680	DO j = LBOUND(zu_s_inner, 2), UBOUND(zu_s_inner, 2)
681	!
682	!-- Topography height on scalar grid. Therefore, determine index of
683	!-- upward-facing surface element on scalar grid.
684	zu_s_inner(i,j) = zu(topo_top_ind(j,i,0))
685	!
686	!-- Topography height on w grid. Therefore, determine index of
687	!-- upward-facing surface element on w grid.
688	zw_w_inner(i,j) = zw(topo_top_ind(j,i,3))
689	ENDDO
690	ENDDO
691	ENDIF
692
693	!
694	!-- In the following, calculate 2D index arrays. Note, these will be removed
695	!-- soon.
696	!-- Allocate outer and inner index arrays for topography and set
697	!-- defaults.
698	ALLOCATE( nzb_s_inner(nysg:nyng,nxlg:nxrg), &
699	nzb_s_outer(nysg:nyng,nxlg:nxrg), &
700	nzb_u_inner(nysg:nyng,nxlg:nxrg), &
701	nzb_u_outer(nysg:nyng,nxlg:nxrg), &
702	nzb_v_inner(nysg:nyng,nxlg:nxrg), &
703	nzb_v_outer(nysg:nyng,nxlg:nxrg), &
704	nzb_w_inner(nysg:nyng,nxlg:nxrg), &
705	nzb_w_outer(nysg:nyng,nxlg:nxrg), &
706	nzb_diff_s_inner(nysg:nyng,nxlg:nxrg), &
707	nzb_diff_s_outer(nysg:nyng,nxlg:nxrg), &
708	nzb_local(nysg:nyng,nxlg:nxrg), &
709	nzb_tmp(nysg:nyng,nxlg:nxrg) )
710	!
711	!-- Initialize 2D-index arrays. Note, these will be removed soon!
712	nzb_local(nys:nyn,nxl:nxr) = topo_top_ind(nys:nyn,nxl:nxr,0)
713	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
714	!
715	!-- Check topography for consistency with model domain. Therefore, use
716	!-- maximum and minium topography-top indices. Note, minimum topography top
717	!-- index is already calculated.
718	IF ( TRIM( topography ) /= 'flat' ) THEN
719	#if defined( __parallel )
720	CALL MPI_ALLREDUCE( MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) ), &
721	nzb_local_max, 1, MPI_INTEGER, MPI_MAX, comm2d, ierr )
722	#else
723	nzb_local_max = MAXVAL( topo_top_ind(nys:nyn,nxl:nxr,0) )
724	#endif
725	nzb_local_min = topo_min_level
726	!
727	!-- Consistency checks
728	IF ( nzb_local_min < 0 .OR. nzb_local_max > nz + 1 ) THEN
729	WRITE( message_string, * ) 'nzb_local values are outside the', &
730	' model domain', &
731	'&MINVAL( nzb_local ) = ', nzb_local_min, &
732	'&MAXVAL( nzb_local ) = ', nzb_local_max
733	CALL message( 'init_grid', 'PA0210', 1, 2, 0, 6, 0 )
734	ENDIF
735	ENDIF
736
737	nzb_s_inner = nzb; nzb_s_outer = nzb
738	nzb_u_inner = nzb; nzb_u_outer = nzb
739	nzb_v_inner = nzb; nzb_v_outer = nzb
740	nzb_w_inner = nzb; nzb_w_outer = nzb
741
742	!
743	!-- Define vertical gridpoint from (or to) which on the usual finite difference
744	!-- form (which does not use surface fluxes) is applied
745	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
746	nzb_diff = nzb + 2
747	ELSE
748	nzb_diff = nzb + 1
749	ENDIF
750
751	nzb_diff_s_inner = nzb_diff; nzb_diff_s_outer = nzb_diff
752	!
753	!-- Set Neumann conditions for topography. Will be removed soon.
754	IF ( .NOT. bc_ns_cyc ) THEN
755	IF ( nys == 0 ) THEN
756	DO i = 1, nbgp
757	nzb_local(nys-i,:) = nzb_local(nys,:)
758	ENDDO
759	ELSEIF ( nyn == ny ) THEN
760	DO i = 1, nbgp
761	nzb_local(ny+i,:) = nzb_local(ny,:)
762	ENDDO
763	ENDIF
764	ENDIF
765
766	IF ( .NOT. bc_lr_cyc ) THEN
767	IF ( nxl == 0 ) THEN
768	DO i = 1, nbgp
769	nzb_local(:,nxl-i) = nzb_local(:,nxl)
770	ENDDO
771	ELSEIF ( nxr == nx ) THEN
772	DO i = 1, nbgp
773	nzb_local(:,nx+i) = nzb_local(:,nx)
774	ENDDO
775	ENDIF
776	ENDIF
777	!
778	!-- Initialization of 2D index arrays, will be removed soon!
779	!-- Initialize nzb_s_inner and nzb_w_inner
780	nzb_s_inner = nzb_local
781	nzb_w_inner = nzb_local
782
783	!
784	!-- Initialize remaining index arrays:
785	!-- first pre-initialize them with nzb_s_inner...
786	nzb_u_inner = nzb_s_inner
787	nzb_u_outer = nzb_s_inner
788	nzb_v_inner = nzb_s_inner
789	nzb_v_outer = nzb_s_inner
790	nzb_w_outer = nzb_s_inner
791	nzb_s_outer = nzb_s_inner
792
793	!
794	!-- nzb_s_outer:
795	!-- extend nzb_local east-/westwards first, then north-/southwards
796	nzb_tmp = nzb_local
797	DO j = nys, nyn
798	DO i = nxl, nxr
799	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i), &
800	nzb_local(j,i+1) )
801	ENDDO
802	ENDDO
803
804	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
805
806	DO i = nxl, nxr
807	DO j = nys, nyn
808	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
809	nzb_tmp(j+1,i) )
810	ENDDO
811	!
812	!-- non-cyclic boundary conditions (overwritten by call of
813	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
814	IF ( nys == 0 ) THEN
815	j = -1
816	nzb_s_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
817	ENDIF
818	IF ( nyn == ny ) THEN
819	j = ny + 1
820	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
821	ENDIF
822	ENDDO
823	!
824	!-- nzb_w_outer:
825	!-- identical to nzb_s_outer
826	nzb_w_outer = nzb_s_outer
827	!
828	!-- nzb_u_inner:
829	!-- extend nzb_local rightwards only
830	nzb_tmp = nzb_local
831	DO j = nys, nyn
832	DO i = nxl, nxr
833	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i) )
834	ENDDO
835	ENDDO
836
837	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
838
839	nzb_u_inner = nzb_tmp
840	!
841	!-- nzb_u_outer:
842	!-- extend current nzb_tmp (nzb_u_inner) north-/southwards
843	DO i = nxl, nxr
844	DO j = nys, nyn
845	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
846	nzb_tmp(j+1,i) )
847	ENDDO
848	!
849	!-- non-cyclic boundary conditions (overwritten by call of
850	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
851	IF ( nys == 0 ) THEN
852	j = -1
853	nzb_u_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
854	ENDIF
855	IF ( nyn == ny ) THEN
856	j = ny + 1
857	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
858	ENDIF
859	ENDDO
860
861	!
862	!-- nzb_v_inner:
863	!-- extend nzb_local northwards only
864	nzb_tmp = nzb_local
865	DO i = nxl, nxr
866	DO j = nys, nyn
867	nzb_tmp(j,i) = MAX( nzb_local(j-1,i), nzb_local(j,i) )
868	ENDDO
869	ENDDO
870
871	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
872	nzb_v_inner = nzb_tmp
873
874	!
875	!-- nzb_v_outer:
876	!-- extend current nzb_tmp (nzb_v_inner) right-/leftwards
877	DO j = nys, nyn
878	DO i = nxl, nxr
879	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i), &
880	nzb_tmp(j,i+1) )
881	ENDDO
882	!
883	!-- non-cyclic boundary conditions (overwritten by call of
884	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
885	IF ( nxl == 0 ) THEN
886	i = -1
887	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i+1), nzb_tmp(j,i) )
888	ENDIF
889	IF ( nxr == nx ) THEN
890	i = nx + 1
891	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i) )
892	ENDIF
893	ENDDO
894
895	!
896	!-- Exchange of lateral boundary values (parallel computers) and cyclic
897	!-- boundary conditions, if applicable.
898	!-- Since nzb_s_inner and nzb_w_inner are derived directly from nzb_local
899	!-- they do not require exchange and are not included here.
900	CALL exchange_horiz_2d_int( nzb_u_inner, nys, nyn, nxl, nxr, nbgp )
901	CALL exchange_horiz_2d_int( nzb_u_outer, nys, nyn, nxl, nxr, nbgp )
902	CALL exchange_horiz_2d_int( nzb_v_inner, nys, nyn, nxl, nxr, nbgp )
903	CALL exchange_horiz_2d_int( nzb_v_outer, nys, nyn, nxl, nxr, nbgp )
904	CALL exchange_horiz_2d_int( nzb_w_outer, nys, nyn, nxl, nxr, nbgp )
905	CALL exchange_horiz_2d_int( nzb_s_outer, nys, nyn, nxl, nxr, nbgp )
906
907	!
908	!-- Set the individual index arrays which define the k index from which on
909	!-- the usual finite difference form (which does not use surface fluxes) is
910	!-- applied
911	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
912	nzb_diff_s_inner = nzb_s_inner + 2
913	nzb_diff_s_outer = nzb_s_outer + 2
914	ELSE
915	nzb_diff_s_inner = nzb_s_inner + 1
916	nzb_diff_s_outer = nzb_s_outer + 1
917	ENDIF
918	!
919	!-- Vertical nesting: communicate vertical grid level arrays between fine and
920	!-- coarse grid
921	IF ( vnested ) CALL vnest_init_grid
922
923	END SUBROUTINE init_grid
924
925
926	! Description:
927	! -----------------------------------------------------------------------------!
928	!> Calculation of the stretching factor through an iterative method. Ideas were
929	!> taken from the paper "Regional stretched grid generation and its application
930	!> to the NCAR RegCM (1999)". Normally, no analytic solution exists because the
931	!> system of equations has two variables (r,l) but four requirements
932	!> (l=integer, r=[0,88;1,2], Eq(6), Eq(5) starting from index j=1) which
933	!> results into an overdetermined system.
934	!------------------------------------------------------------------------------!
935	SUBROUTINE calculate_stretching_factor( number_end )
936
937	USE control_parameters, &
938	ONLY: dz, dz_stretch_factor_array, &
939	dz_stretch_level_end, dz_stretch_level_start, message_string
940
941	USE kinds
942
943	IMPLICIT NONE
944
945	INTEGER(iwp) :: iterations !< number of iterations until stretch_factor_lower/upper_limit is reached
946	INTEGER(iwp) :: l_rounded !< after l_rounded grid levels dz(n) is strechted to dz(n+1) with stretch_factor_2
947	INTEGER(iwp) :: n !< loop variable for stretching
948
949	INTEGER(iwp), INTENT(IN) :: number_end !< number of user-specified end levels for stretching
950
951	REAL(wp) :: delta_l !< absolute difference between l and l_rounded
952	REAL(wp) :: delta_stretch_factor !< absolute difference between stretch_factor_1 and stretch_factor_2
953	REAL(wp) :: delta_total_new !< sum of delta_l and delta_stretch_factor for the next iteration (should be as small as possible)
954	REAL(wp) :: delta_total_old !< sum of delta_l and delta_stretch_factor for the last iteration
955	REAL(wp) :: distance !< distance between dz_stretch_level_start and dz_stretch_level_end (stretching region)
956	REAL(wp) :: l !< value that fulfil Eq. (5) in the paper mentioned above together with stretch_factor_1 exactly
957	REAL(wp) :: numerator !< numerator of the quotient
958	REAL(wp) :: stretch_factor_1 !< stretching factor that fulfil Eq. (5) togehter with l exactly
959	REAL(wp) :: stretch_factor_2 !< stretching factor that fulfil Eq. (6) togehter with l_rounded exactly
960
961	REAL(wp) :: dz_stretch_factor_array_2(9) = 1.08_wp !< Array that contains all stretch_factor_2 that belongs to stretch_factor_1
962
963	REAL(wp), PARAMETER :: stretch_factor_interval = 1.0E-06 !< interval for sampling possible stretching factors
964	REAL(wp), PARAMETER :: stretch_factor_lower_limit = 0.88 !< lowest possible stretching factor
965	REAL(wp), PARAMETER :: stretch_factor_upper_limit = 1.12 !< highest possible stretching factor
966
967
968	l = 0
969	DO n = 1, number_end
970
971	iterations = 1
972	stretch_factor_1 = 1.0
973	stretch_factor_2 = 1.0
974	delta_total_old = 1.0
975
976	IF ( dz(n) > dz(n+1) ) THEN
977	DO WHILE ( stretch_factor_1 >= stretch_factor_lower_limit )
978
979	stretch_factor_1 = 1.0 - iterations * stretch_factor_interval
980	distance = ABS( dz_stretch_level_end(n) - &
981	dz_stretch_level_start(n) )
982	numerator = distance*stretch_factor_1/dz(n) + &
983	stretch_factor_1 - distance/dz(n)
984
985	IF ( numerator > 0.0 ) THEN
986	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0
987	l_rounded = NINT( l )
988	delta_l = ABS( l_rounded - l ) / l
989	ENDIF
990
991	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
992
993	delta_stretch_factor = ABS( stretch_factor_1 - &
994	stretch_factor_2 ) / &
995	stretch_factor_2
996
997	delta_total_new = delta_l + delta_stretch_factor
998
999	!
1000	!-- stretch_factor_1 is taken to guarantee that the stretching
1001	!-- procedure ends as close as possible to dz_stretch_level_end.
1002	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
1003	!-- equal to dz(n+1) after l_rounded grid levels.
1004	IF (delta_total_new < delta_total_old) THEN
1005	dz_stretch_factor_array(n) = stretch_factor_1
1006	dz_stretch_factor_array_2(n) = stretch_factor_2
1007	delta_total_old = delta_total_new
1008	ENDIF
1009
1010	iterations = iterations + 1
1011
1012	ENDDO
1013
1014	ELSEIF ( dz(n) < dz(n+1) ) THEN
1015	DO WHILE ( stretch_factor_1 <= stretch_factor_upper_limit )
1016
1017	stretch_factor_1 = 1.0 + iterations * stretch_factor_interval
1018	distance = ABS( dz_stretch_level_end(n) - &
1019	dz_stretch_level_start(n) )
1020	numerator = distance*stretch_factor_1/dz(n) + &
1021	stretch_factor_1 - distance/dz(n)
1022
1023	l = LOG( numerator ) / LOG( stretch_factor_1 ) - 1.0
1024	l_rounded = NINT( l )
1025	delta_l = ABS( l_rounded - l ) / l
1026
1027	stretch_factor_2 = EXP( LOG( dz(n+1)/dz(n) ) / (l_rounded) )
1028
1029	delta_stretch_factor = ABS( stretch_factor_1 - &
1030	stretch_factor_2 ) / &
1031	stretch_factor_2
1032
1033	delta_total_new = delta_l + delta_stretch_factor
1034
1035	!
1036	!-- stretch_factor_1 is taken to guarantee that the stretching
1037	!-- procedure ends as close as possible to dz_stretch_level_end.
1038	!-- stretch_factor_2 would guarantee that the stretched dz(n) is
1039	!-- equal to dz(n+1) after l_rounded grid levels.
1040	IF (delta_total_new < delta_total_old) THEN
1041	dz_stretch_factor_array(n) = stretch_factor_1
1042	dz_stretch_factor_array_2(n) = stretch_factor_2
1043	delta_total_old = delta_total_new
1044	ENDIF
1045
1046	iterations = iterations + 1
1047	ENDDO
1048
1049	ELSE
1050	message_string= 'Two adjacent values of dz must be different'
1051	CALL message( 'init_grid', 'PA0228', 1, 2, 0, 6, 0 )
1052
1053	ENDIF
1054
1055	!
1056	!-- Check if also the second stretching factor fits into the allowed
1057	!-- interval. If not, print a warning for the user.
1058	IF ( dz_stretch_factor_array_2(n) < stretch_factor_lower_limit .OR. &
1059	dz_stretch_factor_array_2(n) > stretch_factor_upper_limit ) THEN
1060	WRITE( message_string, * ) 'stretch_factor_2 = ', &
1061	dz_stretch_factor_array_2(n), ' which is',&
1062	' responsible for exactly reaching& dz =',&
1063	dz(n+1), 'after a specific amount of', &
1064	' grid levels& exceeds the upper', &
1065	' limit =', stretch_factor_upper_limit, &
1066	' &or lower limit = ', &
1067	stretch_factor_lower_limit
1068	CALL message( 'init_grid', 'PA0499', 0, 1, 0, 6, 0 )
1069
1070	ENDIF
1071	ENDDO
1072
1073	END SUBROUTINE calculate_stretching_factor
1074
1075
1076	! Description:
1077	! -----------------------------------------------------------------------------!
1078	!> Set temporary topography flags and reference buildings on top of underlying
1079	!> orography.
1080	!------------------------------------------------------------------------------!
1081	SUBROUTINE process_topography( topo_3d )
1082
1083	USE arrays_3d, &
1084	ONLY: zu, zw
1085
1086	USE control_parameters, &
1087	ONLY: bc_lr_cyc, bc_ns_cyc, message_string, ocean_mode
1088
1089	USE indices, &
1090	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
1091	nzt
1092
1093	USE netcdf_data_input_mod, &
1094	ONLY: buildings_f, building_id_f, building_type_f, input_pids_static, &
1095	terrain_height_f
1096
1097	USE kinds
1098
1099	USE pegrid
1100
1101	IMPLICIT NONE
1102
1103	INTEGER(iwp) :: i !< running index along x-direction
1104	INTEGER(iwp) :: j !< running index along y-direction
1105	INTEGER(iwp) :: k !< running index along z-direction with respect to numeric grid
1106	INTEGER(iwp) :: k2 !< running index along z-direction with respect to netcdf grid
1107	INTEGER(iwp) :: nr !< index variable indication maximum terrain height for respective building ID
1108	INTEGER(iwp) :: num_build !< counter for number of buildings
1109	INTEGER(iwp) :: topo_top_index !< orography top index, used to map 3D buildings onto terrain
1110
1111	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displace_dum !< displacements of start addresses, used for MPI_ALLGATHERV
1112	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids !< building IDs on entire model domain
1113	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final !< building IDs on entire model domain, multiple occurences are sorted out
1114	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_final_tmp !< temporary array used for resizing
1115	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l !< building IDs on local subdomain
1116	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: build_ids_l_tmp !< temporary array used to resize array of building IDs
1117
1118	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings !< number of buildings with different ID on entire model domain
1119	INTEGER(iwp), DIMENSION(0:numprocs-1) :: num_buildings_l !< number of buildings with different ID on local subdomain
1120
1121	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< input array for 3D topography and dummy array for setting "outer"-flags
1122
1123	REAL(wp) :: ocean_offset !< offset to consider inverse vertical coordinate at topography definition
1124	REAL(wp) :: oro_min = 0.0_wp !< minimum terrain height in entire model domain, used to reference terrain to zero
1125	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max !< maximum terrain height occupied by an building with certain id
1126	REAL(wp), DIMENSION(:), ALLOCATABLE :: oro_max_l !< maximum terrain height occupied by an building with certain id, on local subdomain
1127
1128	!
1129	!-- Reference lowest terrain height to zero. In case the minimum terrain height
1130	!-- is non-zero, all grid points of the lower vertical grid levels might be
1131	!-- entirely below the surface, meaning a waste of computational resources.
1132	!-- In order to avoid this, remove the lowest terrain height. Please note,
1133	!-- in case of a nested run, the global minimum from all parent and childs
1134	!-- need to be remove to avoid steep edges at the child-domain boundaries.
1135	IF ( input_pids_static ) THEN
1136
1137	#if defined( __parallel )
1138	CALL MPI_ALLREDUCE( MINVAL( terrain_height_f%var ), oro_min, 1, &
1139	MPI_REAL, MPI_MIN, MPI_COMM_WORLD, ierr )
1140	#else
1141	oro_min = MINVAL( terrain_height_f%var )
1142	#endif
1143	terrain_height_f%var = terrain_height_f%var - oro_min
1144	!
1145	!-- Give an informative message that terrain height is referenced to zero
1146	IF ( oro_min > 0.0_wp ) THEN
1147	WRITE( message_string, * ) 'Terrain height was internally shifted '//&
1148	'downwards by ', oro_min, 'meter(s) to save ' // &
1149	'computational resources.'
1150	CALL message( 'init_grid', 'PA0505', 0, 0, 0, 6, 0 )
1151	ENDIF
1152	ENDIF
1153
1154	!
1155	!-- In the following, buildings and orography are further preprocessed
1156	!-- before they are mapped on the LES grid.
1157	!-- Buildings are mapped on top of the orography by maintaining the roof
1158	!-- shape of the building. This can be achieved by referencing building on
1159	!-- top of the maximum terrain height within the area occupied by the
1160	!-- respective building. As buildings and terrain height are defined PE-wise,
1161	!-- parallelization of this referencing is required (a building can be
1162	!-- distributed between different PEs).
1163	!-- In a first step, determine the number of buildings with different
1164	!-- building id on each PE. In a next step, all building ids are gathered
1165	!-- into one array which is present to all PEs. For each building ID,
1166	!-- the maximum terrain height occupied by the respective building is
1167	!-- computed and distributed to each PE.
1168	!-- Finally, for each building id and its respective reference orography,
1169	!-- builidings are mapped on top.
1170	!--
1171	!-- First, pre-set topography flags, bit 1 indicates orography, bit 2
1172	!-- buildings
1173	!-- classify the respective surfaces.
1174	topo_3d = IBSET( topo_3d, 0 )
1175	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1176	!
1177	!-- In order to map topography on PALM grid also in case of ocean simulations,
1178	!-- pre-calculate an offset value.
1179	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1180	!
1181	!-- Reference buildings on top of orography. This is not necessary
1182	!-- if topography is read from ASCII file as no distinction between buildings
1183	!-- and terrain height can be made. Moreover, this is also not necessary if
1184	!-- urban-surface and land-surface model are used at the same time.
1185	IF ( input_pids_static ) THEN
1186
1187	IF ( buildings_f%from_file ) THEN
1188	num_buildings_l = 0
1189	num_buildings = 0
1190	!
1191	!-- Allocate at least one element for building ids and give it an inital
1192	!-- negative value that will be overwritten later. This, however, is
1193	!-- necessary in case there all IDs in the model domain are fill values.
1194	ALLOCATE( build_ids_l(1) )
1195	build_ids_l = -1
1196	DO i = nxl, nxr
1197	DO j = nys, nyn
1198	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1199	IF ( num_buildings_l(myid) > 0 ) THEN
1200	IF ( ANY( building_id_f%var(j,i) == build_ids_l ) ) &
1201	THEN
1202	CYCLE
1203	ELSE
1204	num_buildings_l(myid) = num_buildings_l(myid) + 1
1205	!
1206	!-- Resize array with different local building ids
1207	ALLOCATE( build_ids_l_tmp(1:SIZE(build_ids_l)) )
1208	build_ids_l_tmp = build_ids_l
1209	DEALLOCATE( build_ids_l )
1210	ALLOCATE( build_ids_l(1:num_buildings_l(myid)) )
1211	build_ids_l(1:num_buildings_l(myid)-1) = &
1212	build_ids_l_tmp(1:num_buildings_l(myid)-1)
1213	build_ids_l(num_buildings_l(myid)) = building_id_f%var(j,i)
1214	DEALLOCATE( build_ids_l_tmp )
1215	ENDIF
1216	!
1217	!-- First occuring building id on PE
1218	ELSE
1219	num_buildings_l(myid) = num_buildings_l(myid) + 1
1220	build_ids_l(1) = building_id_f%var(j,i)
1221	ENDIF
1222	ENDIF
1223	ENDDO
1224	ENDDO
1225	!
1226	!-- Determine number of different building ids for the entire domain
1227	#if defined( __parallel )
1228	CALL MPI_ALLREDUCE( num_buildings_l, num_buildings, numprocs, &
1229	MPI_INTEGER, MPI_SUM, comm2d, ierr )
1230	#else
1231	num_buildings = num_buildings_l
1232	#endif
1233	!
1234	!-- Gather all buildings ids on each PEs.
1235	!-- First, allocate array encompassing all building ids in model domain.
1236	ALLOCATE( build_ids(1:SUM(num_buildings)) )
1237	#if defined( __parallel )
1238	!
1239	!-- Allocate array for displacements.
1240	!-- As each PE may has a different number of buildings, so that
1241	!-- the block sizes send by each PE may not be equal. Hence,
1242	!-- information about the respective displacement is required, indicating
1243	!-- the respective adress where each MPI-task writes into the receive
1244	!-- buffer array
1245	ALLOCATE( displace_dum(0:numprocs-1) )
1246	displace_dum(0) = 0
1247	DO i = 1, numprocs-1
1248	displace_dum(i) = displace_dum(i-1) + num_buildings(i-1)
1249	ENDDO
1250
1251	CALL MPI_ALLGATHERV( build_ids_l(1:num_buildings_l(myid)), &
1252	num_buildings(myid), &
1253	MPI_INTEGER, &
1254	build_ids, &
1255	num_buildings, &
1256	displace_dum, &
1257	MPI_INTEGER, &
1258	comm2d, ierr )
1259
1260	DEALLOCATE( displace_dum )
1261
1262	#else
1263	build_ids = build_ids_l
1264	#endif
1265
1266	!
1267	!-- Note, in parallel mode building ids can occure mutliple times, as
1268	!-- each PE has send its own ids. Therefore, sort out building ids which
1269	!-- appear more than one time.
1270	num_build = 0
1271	DO nr = 1, SIZE(build_ids)
1272
1273	IF ( ALLOCATED(build_ids_final) ) THEN
1274	IF ( ANY( build_ids(nr) == build_ids_final ) ) THEN
1275	CYCLE
1276	ELSE
1277	num_build = num_build + 1
1278	!
1279	!-- Resize
1280	ALLOCATE( build_ids_final_tmp(1:num_build) )
1281	build_ids_final_tmp(1:num_build-1) = build_ids_final(1:num_build-1)
1282	DEALLOCATE( build_ids_final )
1283	ALLOCATE( build_ids_final(1:num_build) )
1284	build_ids_final(1:num_build-1) = build_ids_final_tmp(1:num_build-1)
1285	build_ids_final(num_build) = build_ids(nr)
1286	DEALLOCATE( build_ids_final_tmp )
1287	ENDIF
1288	ELSE
1289	num_build = num_build + 1
1290	ALLOCATE( build_ids_final(1:num_build) )
1291	build_ids_final(num_build) = build_ids(nr)
1292	ENDIF
1293	ENDDO
1294
1295	!
1296	!-- Determine maximumum terrain height occupied by the respective
1297	!-- building and temporalily store on oro_max
1298	ALLOCATE( oro_max_l(1:SIZE(build_ids_final)) )
1299	ALLOCATE( oro_max(1:SIZE(build_ids_final)) )
1300	oro_max_l = 0.0_wp
1301
1302	DO nr = 1, SIZE(build_ids_final)
1303	oro_max_l(nr) = MAXVAL( &
1304	MERGE( terrain_height_f%var(nys:nyn,nxl:nxr), &
1305	0.0_wp, &
1306	building_id_f%var(nys:nyn,nxl:nxr) == &
1307	build_ids_final(nr) ) )
1308	ENDDO
1309
1310	#if defined( __parallel )
1311	IF ( SIZE(build_ids_final) >= 1 ) THEN
1312	CALL MPI_ALLREDUCE( oro_max_l, oro_max, SIZE( oro_max ), MPI_REAL,&
1313	MPI_MAX, comm2d, ierr )
1314	ENDIF
1315	#else
1316	oro_max = oro_max_l
1317	#endif
1318	!
1319	!-- Finally, determine discrete grid height of maximum orography occupied
1320	!-- by a building. Use all-or-nothing approach, i.e. if terrain
1321	!-- exceeds the scalar level the grid box is fully terrain and the
1322	!-- maximum terrain is set to the zw level.
1323	!-- terrain or
1324	oro_max_l = 0.0
1325	DO nr = 1, SIZE(build_ids_final)
1326	DO k = nzb, nzt
1327	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1328	oro_max_l(nr) = zw(k) - ocean_offset
1329	ENDDO
1330	oro_max(nr) = oro_max_l(nr)
1331	ENDDO
1332	ENDIF
1333	!
1334	!-- Allocate array for storing terrain height under buildings
1335	IF ( buildings_f%from_file ) THEN
1336	ALLOCATE( buildings_f%oro_max(nysg:nyng,nxlg:nxrg) )
1337	buildings_f%oro_max = buildings_f%fill1
1338	END IF
1339	!
1340	!-- Map orography as well as buildings onto grid.
1341	DO i = nxl, nxr
1342	DO j = nys, nyn
1343	topo_top_index = 0
1344	!
1345	!-- Obtain index in global building_id array
1346	IF ( buildings_f%from_file ) THEN
1347	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1348	!
1349	!-- Determine index where maximum terrain height occupied by
1350	!-- the respective building height is stored.
1351	nr = MINLOC( ABS( build_ids_final - &
1352	building_id_f%var(j,i) ), DIM = 1 )
1353	!
1354	!-- Save grid-indexed oro_max
1355	buildings_f%oro_max(j,i) = oro_max(nr)
1356	ENDIF
1357	ENDIF
1358	DO k = nzb, nzt
1359	!
1360	!-- In a first step, if grid point is below or equal the given
1361	!-- terrain height, grid point is flagged to be of type natural.
1362	!-- Please note, in case there is also a building which is lower
1363	!-- than the vertical grid spacing, initialization of surface
1364	!-- attributes will not be correct as given surface information
1365	!-- will not be in accordance to the classified grid points.
1366	!-- Hence, in this case, also a building flag.
1367	IF ( zu(k) - ocean_offset <= terrain_height_f%var(j,i) ) THEN
1368	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1369	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1370	topo_top_index = k ! topo_top_index + 1
1371	ENDIF
1372	!
1373	!-- Set building grid points. Here, only consider 2D buildings.
1374	!-- 3D buildings require separate treatment.
1375	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1376	!
1377	!-- Fill-up the terrain to the level of maximum orography
1378	!-- within the building-covered area.
1379	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1380	!
1381	!-- Note, oro_max is always on zw level
1382	IF ( zu(k) - ocean_offset < oro_max(nr) ) THEN
1383	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1384	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1385	ELSEIF ( zu(k) - ocean_offset <= &
1386	oro_max(nr) + buildings_f%var_2d(j,i) ) THEN
1387	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1388	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1389	ENDIF
1390	ENDIF
1391	ENDIF
1392	ENDDO
1393	!
1394	!-- Special treatment for non grid-resolved buildings. This case,
1395	!-- the uppermost terrain grid point is flagged as building as well
1396	!-- well, even though no building exists at all. However, the
1397	!-- surface element will be identified as urban-surface and the
1398	!-- input data provided by the drivers is consistent to the surface
1399	!-- classification. Else, all non grid-resolved buildings would vanish
1400	!-- and identified as terrain grid points, which, however, won't be
1401	!-- consistent with the input data.
1402	IF ( buildings_f%from_file .AND. buildings_f%lod == 1 ) THEN
1403	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1404	DO k = nzb, nzt
1405	IF( zw(k) - ocean_offset == oro_max(nr) ) THEN
1406	IF ( buildings_f%var_2d(j,i) <= zu(k+1) - zw(k) ) THEN
1407	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1408	ENDIF
1409	ENDIF
1410	ENDDO
1411	ENDIF
1412	ENDIF
1413	!
1414	!-- Map 3D buildings onto terrain height.
1415	!-- In case of any slopes, map building on top of maximum terrain
1416	!-- height covered by the building. In other words, extend
1417	!-- building down to the respective local terrain-surface height.
1418	IF ( buildings_f%from_file .AND. buildings_f%lod == 2 ) THEN
1419	IF ( building_id_f%var(j,i) /= building_id_f%fill ) THEN
1420	!
1421	!-- Extend building down to the terrain surface, i.e. fill-up
1422	!-- surface irregularities below a building. Note, oro_max
1423	!-- is already a discrete height according to the all-or-nothing
1424	!-- approach, i.e. grid box is either topography or atmosphere,
1425	!-- terrain top is defined at upper bound of the grid box.
1426	!-- Hence, check for zw in this case.
1427	!-- Note, do this only for buildings which are surface mounted,
1428	!-- i.e. building types 1-6. Below bridges, which are represented
1429	!-- exclusively by building type 7, terrain shape should be
1430	!-- maintained.
1431	IF ( building_type_f%from_file ) THEN
1432	IF ( building_type_f%var(j,i) /= 7 ) THEN
1433	DO k = topo_top_index + 1, nzt + 1
1434	IF ( zu(k) - ocean_offset <= oro_max(nr) ) THEN
1435	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1436	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1437	ENDIF
1438	ENDDO
1439	!
1440	!-- After surface irregularities are smoothen, determine
1441	!-- lower start index where building starts.
1442	DO k = nzb, nzt
1443	IF ( zu(k) - ocean_offset <= oro_max(nr) ) &
1444	topo_top_index = k
1445	ENDDO
1446	ENDIF
1447	ENDIF
1448	!
1449	!-- Finally, map building on top.
1450	k2 = 0
1451	DO k = topo_top_index, nzt + 1
1452	IF ( k2 <= buildings_f%nz-1 ) THEN
1453	IF ( buildings_f%var_3d(k2,j,i) == 1 ) THEN
1454	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1455	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1456	ENDIF
1457	ENDIF
1458	k2 = k2 + 1
1459	ENDDO
1460	ENDIF
1461	ENDIF
1462	ENDDO
1463	ENDDO
1464	!
1465	!-- Horizontal exchange the oro_max array, which is required to for
1466	!-- initialization of building-surface properties.
1467	IF ( ALLOCATED( buildings_f%oro_max ) ) THEN
1468	CALL exchange_horiz_2d( buildings_f%oro_max(:,:), nbgp )
1469	ENDIF
1470	!
1471	!-- Deallocate temporary arrays required for processing and reading data
1472	IF ( ALLOCATED( oro_max ) ) DEALLOCATE( oro_max )
1473	IF ( ALLOCATED( oro_max_l ) ) DEALLOCATE( oro_max_l )
1474	IF ( ALLOCATED( build_ids_final ) ) DEALLOCATE( build_ids_final )
1475	!
1476	!-- Topography input via ASCII format.
1477	ELSE
1478	ocean_offset = MERGE( zw(0), 0.0_wp, ocean_mode )
1479	!
1480	!-- Initialize topography bit 0 (indicates obstacle) everywhere to zero
1481	!-- and clear all grid points at nzb, where alway a surface is defined.
1482	!-- Further, set also bit 1 (indicates terrain) at nzb, which is further
1483	!-- used for masked data output and further processing. Note, in the
1484	!-- ASCII case no distinction is made between buildings and terrain,
1485	!-- so that setting of bit 1 and 2 at the same time has no effect.
1486	topo_3d = IBSET( topo_3d, 0 )
1487	topo_3d(nzb,:,:) = IBCLR( topo_3d(nzb,:,:), 0 )
1488	topo_3d(nzb,:,:) = IBSET( topo_3d(nzb,:,:), 1 )
1489	DO i = nxl, nxr
1490	DO j = nys, nyn
1491	DO k = nzb, nzt
1492	!
1493	!-- Flag topography for all grid points which are below
1494	!-- the local topography height.
1495	!-- Note, each topography is flagged as building.
1496	IF ( zu(k) - ocean_offset <= buildings_f%var_2d(j,i) ) THEN
1497	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1498	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 ) !indicates building
1499	ENDIF
1500	ENDDO
1501	ENDDO
1502	ENDDO
1503	ENDIF
1504
1505	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1506
1507	IF ( .NOT. bc_ns_cyc ) THEN
1508	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1509	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1510	ENDIF
1511
1512	IF ( .NOT. bc_lr_cyc ) THEN
1513	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1514	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1515	ENDIF
1516
1517	END SUBROUTINE process_topography
1518
1519
1520	! Description:
1521	! -----------------------------------------------------------------------------!
1522	!> Filter topography, i.e. fill holes resolved by only one grid point.
1523	!> Such holes are suspected to lead to velocity blow-ups as continuity
1524	!> equation on discrete grid cannot be fulfilled in such case.
1525	!------------------------------------------------------------------------------!
1526	SUBROUTINE filter_topography( topo_3d )
1527
1528	USE control_parameters, &
1529	ONLY: bc_lr_cyc, bc_ns_cyc, message_string
1530
1531	USE indices, &
1532	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, nzt
1533
1534	USE netcdf_data_input_mod, &
1535	ONLY: building_id_f, building_type_f
1536
1537	USE pegrid
1538
1539	IMPLICIT NONE
1540
1541	LOGICAL :: filled = .FALSE. !< flag indicating if holes were filled
1542
1543	INTEGER(iwp) :: i !< running index along x-direction
1544	INTEGER(iwp) :: j !< running index along y-direction
1545	INTEGER(iwp) :: k !< running index along z-direction
1546	INTEGER(iwp) :: num_hole !< number of holes (in topography) resolved by only one grid point
1547	INTEGER(iwp) :: num_hole_l !< number of holes (in topography) resolved by only one grid point on local PE
1548	INTEGER(iwp) :: num_wall !< number of surrounding vertical walls for a single grid point
1549
1550	INTEGER(iwp), DIMENSION(:,:,:), ALLOCATABLE :: topo_tmp !< temporary 3D-topography used to fill holes
1551	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo_3d !< 3D-topography array merging buildings and orography
1552	!
1553	!-- Before checking for holes, set lateral boundary conditions for
1554	!-- topography. After hole-filling, boundary conditions must be set again.
1555	!-- Several iterations are performed, in order to fill holes which might
1556	!-- emerge by the filling-algorithm itself.
1557	ALLOCATE( topo_tmp(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
1558	topo_tmp = 0
1559
1560	num_hole = 99999
1561	DO WHILE ( num_hole > 0 )
1562
1563	num_hole = 0
1564	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1565	!
1566	!-- Exchange also building ID and type. Note, building_type is an one-byte
1567	!-- variable.
1568	IF ( building_id_f%from_file ) &
1569	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1570	IF ( building_type_f%from_file ) &
1571	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1572
1573	topo_tmp = topo_3d
1574	!
1575	!-- In case of non-cyclic lateral boundaries, assume lateral boundary to be
1576	!-- a solid wall. Thus, intermediate spaces of one grid point between
1577	!-- boundary and some topographic structure will be filled.
1578	IF ( .NOT. bc_ns_cyc ) THEN
1579	IF ( nys == 0 ) topo_tmp(:,-1,:) = IBCLR( topo_tmp(:,0,:), 0 )
1580	IF ( nyn == ny ) topo_tmp(:,ny+1,:) = IBCLR( topo_tmp(:,ny,:), 0 )
1581	ENDIF
1582
1583	IF ( .NOT. bc_lr_cyc ) THEN
1584	IF ( nxl == 0 ) topo_tmp(:,:,-1) = IBCLR( topo_tmp(:,:,0), 0 )
1585	IF ( nxr == nx ) topo_tmp(:,:,nx+1) = IBCLR( topo_tmp(:,:,nx), 0 )
1586	ENDIF
1587
1588	num_hole_l = 0
1589	DO i = nxl, nxr
1590	DO j = nys, nyn
1591	DO k = nzb+1, nzt
1592	IF ( BTEST( topo_tmp(k,j,i), 0 ) ) THEN
1593	num_wall = 0
1594	IF ( .NOT. BTEST( topo_tmp(k,j-1,i), 0 ) ) &
1595	num_wall = num_wall + 1
1596	IF ( .NOT. BTEST( topo_tmp(k,j+1,i), 0 ) ) &
1597	num_wall = num_wall + 1
1598	IF ( .NOT. BTEST( topo_tmp(k,j,i-1), 0 ) ) &
1599	num_wall = num_wall + 1
1600	IF ( .NOT. BTEST( topo_tmp(k,j,i+1), 0 ) ) &
1601	num_wall = num_wall + 1
1602	IF ( .NOT. BTEST( topo_tmp(k-1,j,i), 0 ) ) &
1603	num_wall = num_wall + 1
1604	IF ( .NOT. BTEST( topo_tmp(k+1,j,i), 0 ) ) &
1605	num_wall = num_wall + 1
1606
1607	IF ( num_wall >= 4 ) THEN
1608	num_hole_l = num_hole_l + 1
1609	!
1610	!-- Clear flag 0 and set special flag ( bit 4) to indicate
1611	!-- that new topography point is a result of filtering process.
1612	topo_3d(k,j,i) = IBCLR( topo_3d(k,j,i), 0 )
1613	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 4 )
1614	!
1615	!-- If filled grid point is occupied by a building, classify
1616	!-- it as building grid point.
1617	IF ( building_type_f%from_file ) THEN
1618	IF ( building_type_f%var(j,i) /= &
1619	building_type_f%fill .OR. &
1620	building_type_f%var(j+1,i) /= &
1621	building_type_f%fill .OR. &
1622	building_type_f%var(j-1,i) /= &
1623	building_type_f%fill .OR. &
1624	building_type_f%var(j,i+1) /= &
1625	building_type_f%fill .OR. &
1626	building_type_f%var(j,i-1) /= &
1627	building_type_f%fill ) THEN
1628	!
1629	!-- Set flag indicating building surfaces
1630	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 2 )
1631	!
1632	!-- Set building_type and ID at this position if not
1633	!-- already set. This is required for proper
1634	!-- initialization of urban-surface energy balance
1635	!-- solver.
1636	IF ( building_type_f%var(j,i) == &
1637	building_type_f%fill ) THEN
1638
1639	IF ( building_type_f%var(j+1,i) /= &
1640	building_type_f%fill ) THEN
1641	building_type_f%var(j,i) = &
1642	building_type_f%var(j+1,i)
1643	building_id_f%var(j,i) = &
1644	building_id_f%var(j+1,i)
1645	ELSEIF ( building_type_f%var(j-1,i) /= &
1646	building_type_f%fill ) THEN
1647	building_type_f%var(j,i) = &
1648	building_type_f%var(j-1,i)
1649	building_id_f%var(j,i) = &
1650	building_id_f%var(j-1,i)
1651	ELSEIF ( building_type_f%var(j,i+1) /= &
1652	building_type_f%fill ) THEN
1653	building_type_f%var(j,i) = &
1654	building_type_f%var(j,i+1)
1655	building_id_f%var(j,i) = &
1656	building_id_f%var(j,i+1)
1657	ELSEIF ( building_type_f%var(j,i-1) /= &
1658	building_type_f%fill ) THEN
1659	building_type_f%var(j,i) = &
1660	building_type_f%var(j,i-1)
1661	building_id_f%var(j,i) = &
1662	building_id_f%var(j,i-1)
1663	ENDIF
1664	ENDIF
1665	ENDIF
1666	ENDIF
1667	!
1668	!-- If filled grid point is already classified as building
1669	!-- everything is fine, else classify this grid point as
1670	!-- natural type grid point. This case, values for the
1671	!-- surface type are already set.
1672	IF ( .NOT. BTEST( topo_3d(k,j,i), 2 ) ) THEN
1673	topo_3d(k,j,i) = IBSET( topo_3d(k,j,i), 1 )
1674	ENDIF
1675	ENDIF
1676	ENDIF
1677	ENDDO
1678	ENDDO
1679	ENDDO
1680	!
1681	!-- Count the total number of holes, required for informative message.
1682	#if defined( __parallel )
1683	CALL MPI_ALLREDUCE( num_hole_l, num_hole, 1, MPI_INTEGER, MPI_SUM, &
1684	comm2d, ierr )
1685	#else
1686	num_hole = num_hole_l
1687	#endif
1688	IF ( num_hole > 0 .AND. .NOT. filled ) filled = .TRUE.
1689
1690	ENDDO
1691	!
1692	!-- Create an informative message if any holes were filled.
1693	IF ( filled ) THEN
1694	WRITE( message_string, * ) 'Topography was filtered, i.e. holes ' // &
1695	'resolved by only one grid point ' // &
1696	'were filled during initialization.'
1697	CALL message( 'init_grid', 'PA0430', 0, 0, 0, 6, 0 )
1698	ENDIF
1699
1700	DEALLOCATE( topo_tmp )
1701	!
1702	!-- Finally, exchange topo_3d array again and if necessary set Neumann boundary
1703	!-- condition in case of non-cyclic lateral boundaries.
1704	CALL exchange_horiz_int( topo_3d, nys, nyn, nxl, nxr, nzt, nbgp )
1705
1706	IF ( .NOT. bc_ns_cyc ) THEN
1707	IF ( nys == 0 ) topo_3d(:,-1,:) = topo_3d(:,0,:)
1708	IF ( nyn == ny ) topo_3d(:,ny+1,:) = topo_3d(:,ny,:)
1709	ENDIF
1710
1711	IF ( .NOT. bc_lr_cyc ) THEN
1712	IF ( nxl == 0 ) topo_3d(:,:,-1) = topo_3d(:,:,0)
1713	IF ( nxr == nx ) topo_3d(:,:,nx+1) = topo_3d(:,:,nx)
1714	ENDIF
1715	!
1716	!-- Exchange building ID and type. Note, building_type is an one-byte variable.
1717	IF ( building_id_f%from_file ) &
1718	CALL exchange_horiz_2d_int( building_id_f%var, nys, nyn, nxl, nxr, nbgp )
1719	IF ( building_type_f%from_file ) &
1720	CALL exchange_horiz_2d_byte( building_type_f%var, nys, nyn, nxl, nxr, nbgp )
1721
1722	END SUBROUTINE filter_topography
1723
1724
1725	! Description:
1726	! -----------------------------------------------------------------------------!
1727	!> Reads topography information from file or sets generic topography. Moreover,
1728	!> all topography-relevant topography arrays are initialized, and grid flags
1729	!> are set.
1730	!------------------------------------------------------------------------------!
1731	SUBROUTINE init_topo( topo )
1732
1733	USE arrays_3d, &
1734	ONLY: zw
1735
1736	USE control_parameters, &
1737	ONLY: bc_lr_cyc, bc_ns_cyc, building_height, building_length_x, &
1738	building_length_y, building_wall_left, building_wall_south, &
1739	canyon_height, canyon_wall_left, canyon_wall_south, &
1740	canyon_width_x, canyon_width_y, dp_level_ind_b, dz, &
1741	message_string, topography, topography_grid_convention, &
1742	tunnel_height, tunnel_length, tunnel_width_x, tunnel_width_y, &
1743	tunnel_wall_depth
1744
1745	USE grid_variables, &
1746	ONLY: dx, dy
1747
1748	USE indices, &
1749	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nz, &
1750	nzb, nzt
1751
1752	USE kinds
1753
1754	USE netcdf_data_input_mod, &
1755	ONLY: buildings_f, terrain_height_f
1756
1757	USE pegrid
1758
1759	IMPLICIT NONE
1760
1761	INTEGER(iwp) :: bh !< temporary vertical index of building height
1762	INTEGER(iwp) :: blx !< grid point number of building size along x
1763	INTEGER(iwp) :: bly !< grid point number of building size along y
1764	INTEGER(iwp) :: bxl !< index for left building wall
1765	INTEGER(iwp) :: bxr !< index for right building wall
1766	INTEGER(iwp) :: byn !< index for north building wall
1767	INTEGER(iwp) :: bys !< index for south building wall
1768	INTEGER(iwp) :: ch !< temporary vertical index for canyon height
1769	INTEGER(iwp) :: cwx !< grid point number of canyon size along x
1770	INTEGER(iwp) :: cwy !< grid point number of canyon size along y
1771	INTEGER(iwp) :: cxl !< index for left canyon wall
1772	INTEGER(iwp) :: cxr !< index for right canyon wall
1773	INTEGER(iwp) :: cyn !< index for north canyon wall
1774	INTEGER(iwp) :: cys !< index for south canyon wall
1775	INTEGER(iwp) :: i !< index variable along x
1776	INTEGER(iwp) :: j !< index variable along y
1777	INTEGER(iwp) :: k !< index variable along z
1778	INTEGER(iwp) :: hv_in !< heavyside function to model inner tunnel surface
1779	INTEGER(iwp) :: hv_out !< heavyside function to model outer tunnel surface
1780	INTEGER(iwp) :: txe_out !< end position of outer tunnel wall in x
1781	INTEGER(iwp) :: txs_out !< start position of outer tunnel wall in x
1782	INTEGER(iwp) :: tye_out !< end position of outer tunnel wall in y
1783	INTEGER(iwp) :: tys_out !< start position of outer tunnel wall in y
1784	INTEGER(iwp) :: txe_in !< end position of inner tunnel wall in x
1785	INTEGER(iwp) :: txs_in !< start position of inner tunnel wall in x
1786	INTEGER(iwp) :: tye_in !< end position of inner tunnel wall in y
1787	INTEGER(iwp) :: tys_in !< start position of inner tunnel wall in y
1788	INTEGER(iwp) :: td !< tunnel wall depth
1789	INTEGER(iwp) :: th !< height of outer tunnel wall
1790
1791	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
1792	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
1793	!
1794	!-- Check for correct setting of the namelist parameter topography. If
1795	!-- topography information is read from file but topography = 'flat',
1796	!-- initialization does not properly.
1797	IF ( ( buildings_f%from_file .OR. terrain_height_f%from_file ) .AND. &
1798	TRIM( topography ) /= 'read_from_file' ) THEN
1799	message_string = 'If topography information is provided (via ' // &
1800	'Netcdf or ASCII input) topography = ' // &
1801	'"read_from_file" is required.'
1802	CALL message( 'init_grid', 'PA0437', 1, 2, 0, 6, 0 )
1803	ENDIF
1804	!
1805	!-- Set outer and inner index arrays for non-flat topography.
1806	!-- Here consistency checks concerning domain size and periodicity are
1807	!-- necessary.
1808	!-- Within this SELECT CASE structure only nzb_local is initialized
1809	!-- individually depending on the chosen topography type, all other index
1810	!-- arrays are initialized further below.
1811	SELECT CASE ( TRIM( topography ) )
1812
1813	CASE ( 'flat' )
1814	!
1815	!-- Initialilize 3D topography array, used later for initializing flags
1816	topo(nzb+1:nzt+1,:,:) = IBSET( topo(nzb+1:nzt+1,:,:), 0 )
1817
1818	CASE ( 'single_building' )
1819	!
1820	!-- Single rectangular building, by default centered in the middle of the
1821	!-- total domain
1822	blx = NINT( building_length_x / dx )
1823	bly = NINT( building_length_y / dy )
1824	bh = MINLOC( ABS( zw - building_height ), 1 ) - 1
1825	IF ( ABS( zw(bh) - building_height ) == &
1826	ABS( zw(bh+1) - building_height ) ) bh = bh + 1
1827	IF ( building_wall_left == 9999999.9_wp ) THEN
1828	building_wall_left = ( nx + 1 - blx ) / 2 * dx
1829	ENDIF
1830	bxl = NINT( building_wall_left / dx )
1831	bxr = bxl + blx
1832
1833	IF ( building_wall_south == 9999999.9_wp ) THEN
1834	building_wall_south = ( ny + 1 - bly ) / 2 * dy
1835	ENDIF
1836	bys = NINT( building_wall_south / dy )
1837	byn = bys + bly
1838
1839	!
1840	!-- Building size has to meet some requirements
1841	IF ( ( bxl < 1 ) .OR. ( bxr > nx-1 ) .OR. ( bxr < bxl+3 ) .OR. &
1842	( bys < 1 ) .OR. ( byn > ny-1 ) .OR. ( byn < bys+3 ) ) THEN
1843	WRITE( message_string, * ) 'inconsistent building parameters:', &
1844	'&bxl=', bxl, 'bxr=', bxr, 'bys=', bys, &
1845	'byn=', byn, 'nx=', nx, 'ny=', ny
1846	CALL message( 'init_grid', 'PA0203', 1, 2, 0, 6, 0 )
1847	ENDIF
1848
1849	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1850	nzb_local = 0
1851	!
1852	!-- Define the building.
1853	IF ( bxl <= nxr .AND. bxr >= nxl .AND. &
1854	bys <= nyn .AND. byn >= nys ) &
1855	nzb_local(MAX(nys,bys):MIN(nyn,byn),MAX(nxl,bxl):MIN(nxr,bxr)) = bh
1856	!
1857	!-- Set bit array on basis of nzb_local
1858	DO i = nxl, nxr
1859	DO j = nys, nyn
1860	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1861	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1862	ENDDO
1863	ENDDO
1864
1865	DEALLOCATE( nzb_local )
1866
1867	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1868	!
1869	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1870	!-- boundary conditions for topography.
1871	IF ( .NOT. bc_ns_cyc ) THEN
1872	IF ( nys == 0 ) THEN
1873	DO i = 1, nbgp
1874	topo(:,nys-i,:) = topo(:,nys,:)
1875	ENDDO
1876	ENDIF
1877	IF ( nyn == ny ) THEN
1878	DO i = 1, nbgp
1879	topo(:,nyn+i,:) = topo(:,nyn,:)
1880	ENDDO
1881	ENDIF
1882	ENDIF
1883	IF ( .NOT. bc_lr_cyc ) THEN
1884	IF ( nxl == 0 ) THEN
1885	DO i = 1, nbgp
1886	topo(:,:,nxl-i) = topo(:,:,nxl)
1887	ENDDO
1888	ENDIF
1889	IF ( nxr == nx ) THEN
1890	DO i = 1, nbgp
1891	topo(:,:,nxr+i) = topo(:,:,nxr)
1892	ENDDO
1893	ENDIF
1894	ENDIF
1895
1896	CASE ( 'single_street_canyon' )
1897	!
1898	!-- Single quasi-2D street canyon of infinite length in x or y direction.
1899	!-- The canyon is centered in the other direction by default.
1900	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1901	!
1902	!-- Street canyon in y direction
1903	cwx = NINT( canyon_width_x / dx )
1904	IF ( canyon_wall_left == 9999999.9_wp ) THEN
1905	canyon_wall_left = ( nx + 1 - cwx ) / 2 * dx
1906	ENDIF
1907	cxl = NINT( canyon_wall_left / dx )
1908	cxr = cxl + cwx
1909	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1910	!
1911	!-- Street canyon in x direction
1912	cwy = NINT( canyon_width_y / dy )
1913	IF ( canyon_wall_south == 9999999.9_wp ) THEN
1914	canyon_wall_south = ( ny + 1 - cwy ) / 2 * dy
1915	ENDIF
1916	cys = NINT( canyon_wall_south / dy )
1917	cyn = cys + cwy
1918
1919	ELSE
1920
1921	message_string = 'no street canyon width given'
1922	CALL message( 'init_grid', 'PA0204', 1, 2, 0, 6, 0 )
1923
1924	ENDIF
1925
1926	ch = MINLOC( ABS( zw - canyon_height ), 1 ) - 1
1927	IF ( ABS( zw(ch) - canyon_height ) == &
1928	ABS( zw(ch+1) - canyon_height ) ) ch = ch + 1
1929	dp_level_ind_b = ch
1930	!
1931	!-- Street canyon size has to meet some requirements
1932	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1933	IF ( ( cxl < 1 ) .OR. ( cxr > nx-1 ) .OR. ( cwx < 3 ) .OR. &
1934	( ch < 3 ) ) THEN
1935	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1936	'&cxl=', cxl, ' cxr=', cxr, &
1937	' cwx=', cwx, &
1938	' ch=', ch, ' nx=', nx, ' ny=', ny
1939	CALL message( 'init_grid', 'PA0205', 1, 2, 0, 6, 0 )
1940	ENDIF
1941	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1942	IF ( ( cys < 1 ) .OR. ( cyn > ny-1 ) .OR. ( cwy < 3 ) .OR. &
1943	( ch < 3 ) ) THEN
1944	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
1945	'&cys=', cys, ' cyn=', cyn, &
1946	' cwy=', cwy, &
1947	' ch=', ch, ' nx=', nx, ' ny=', ny
1948	CALL message( 'init_grid', 'PA0206', 1, 2, 0, 6, 0 )
1949	ENDIF
1950	ENDIF
1951	IF ( canyon_width_x /= 9999999.9_wp .AND. &
1952	canyon_width_y /= 9999999.9_wp ) THEN
1953	message_string = 'inconsistent canyon parameters:' // &
1954	'&street canyon can only be oriented' // &
1955	' either in x- or in y-direction'
1956	CALL message( 'init_grid', 'PA0207', 1, 2, 0, 6, 0 )
1957	ENDIF
1958
1959	ALLOCATE( nzb_local(nysg:nyng,nxlg:nxrg) )
1960	nzb_local = ch
1961	IF ( canyon_width_x /= 9999999.9_wp ) THEN
1962	IF ( cxl <= nxr .AND. cxr >= nxl ) &
1963	nzb_local(:,MAX(nxl,cxl+1):MIN(nxr,cxr-1)) = 0
1964	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
1965	IF ( cys <= nyn .AND. cyn >= nys ) &
1966	nzb_local(MAX(nys,cys+1):MIN(nyn,cyn-1),:) = 0
1967	ENDIF
1968	!
1969	!-- Set bit array on basis of nzb_local
1970	DO i = nxl, nxr
1971	DO j = nys, nyn
1972	topo(nzb_local(j,i)+1:nzt+1,j,i) = &
1973	IBSET( topo(nzb_local(j,i)+1:nzt+1,j,i), 0 )
1974	ENDDO
1975	ENDDO
1976	DEALLOCATE( nzb_local )
1977
1978	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
1979	!
1980	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
1981	!-- boundary conditions for topography.
1982	IF ( .NOT. bc_ns_cyc ) THEN
1983	IF ( nys == 0 ) THEN
1984	DO i = 1, nbgp
1985	topo(:,nys-i,:) = topo(:,nys,:)
1986	ENDDO
1987	ENDIF
1988	IF ( nyn == ny ) THEN
1989	DO i = 1, nbgp
1990	topo(:,nyn+i,:) = topo(:,nyn,:)
1991	ENDDO
1992	ENDIF
1993	ENDIF
1994	IF ( .NOT. bc_lr_cyc ) THEN
1995	IF ( nxl == 0 ) THEN
1996	DO i = 1, nbgp
1997	topo(:,:,nxl-i) = topo(:,:,nxl)
1998	ENDDO
1999	ENDIF
2000	IF ( nxr == nx ) THEN
2001	DO i = 1, nbgp
2002	topo(:,:,nxr+i) = topo(:,:,nxr)
2003	ENDDO
2004	ENDIF
2005	ENDIF
2006
2007	CASE ( 'tunnel' )
2008
2009	!
2010	!-- Tunnel height
2011	IF ( tunnel_height == 9999999.9_wp ) THEN
2012	th = zw( INT( 0.2 * nz) )
2013	ELSE
2014	th = tunnel_height
2015	ENDIF
2016	!
2017	!-- Tunnel-wall depth
2018	IF ( tunnel_wall_depth == 9999999.9_wp ) THEN
2019	td = MAX ( dx, dy, dz(1) )
2020	ELSE
2021	td = tunnel_wall_depth
2022	ENDIF
2023	!
2024	!-- Check for tunnel width
2025	IF ( tunnel_width_x == 9999999.9_wp .AND. &
2026	tunnel_width_y == 9999999.9_wp ) THEN
2027	message_string = 'No tunnel width is given. '
2028	CALL message( 'init_grid', 'PA0280', 1, 2, 0, 6, 0 )
2029	ENDIF
2030	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
2031	tunnel_width_y /= 9999999.9_wp ) THEN
2032	message_string = 'Inconsistent tunnel parameters:' // &
2033	'tunnel can only be oriented' // &
2034	'either in x- or in y-direction.'
2035	CALL message( 'init_grid', 'PA0281', 1, 2, 0, 6, 0 )
2036	ENDIF
2037	!
2038	!-- Tunnel axis along y
2039	IF ( tunnel_width_x /= 9999999.9_wp ) THEN
2040	IF ( tunnel_width_x > ( nx + 1 ) * dx ) THEN
2041	message_string = 'Tunnel width too large'
2042	CALL message( 'init_grid', 'PA0282', 1, 2, 0, 6, 0 )
2043	ENDIF
2044
2045	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_width_x * 0.5_wp )
2046	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_width_x * 0.5_wp )
2047	txs_in = INT( ( nx + 1 ) * 0.5_wp * dx - &
2048	( tunnel_width_x * 0.5_wp - td ) )
2049	txe_in = INT( ( nx + 1 ) * 0.5_wp * dx + &
2050	( tunnel_width_x * 0.5_wp - td ) )
2051
2052	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_length * 0.5_wp )
2053	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_length * 0.5_wp )
2054	tys_in = tys_out
2055	tye_in = tye_out
2056	ENDIF
2057	IF ( tunnel_width_x /= 9999999.9_wp .AND. &
2058	tunnel_width_x - 2.0_wp * td <= 2.0_wp * dx ) &
2059	THEN
2060	message_string = 'Tunnel width too small'
2061	CALL message( 'init_grid', 'PA0175', 1, 2, 0, 6, 0 )
2062	ENDIF
2063	IF ( tunnel_width_y /= 9999999.9_wp .AND. &
2064	tunnel_width_y - 2.0_wp * td <= 2.0_wp * dy ) &
2065	THEN
2066	message_string = 'Tunnel width too small'
2067	CALL message( 'init_grid', 'PA0455', 1, 2, 0, 6, 0 )
2068	ENDIF
2069	!
2070	!-- Tunnel axis along x
2071	IF ( tunnel_width_y /= 9999999.9_wp ) THEN
2072	IF ( tunnel_width_y > ( ny + 1 ) * dy ) THEN
2073	message_string = 'Tunnel width too large'
2074	CALL message( 'init_grid', 'PA0456', 1, 2, 0, 6, 0 )
2075	ENDIF
2076
2077	txs_out = INT( ( nx + 1 ) * 0.5_wp * dx - tunnel_length * 0.5_wp )
2078	txe_out = INT( ( nx + 1 ) * 0.5_wp * dx + tunnel_length * 0.5_wp )
2079	txs_in = txs_out
2080	txe_in = txe_out
2081
2082	tys_out = INT( ( ny + 1 ) * 0.5_wp * dy - tunnel_width_y * 0.5_wp )
2083	tye_out = INT( ( ny + 1 ) * 0.5_wp * dy + tunnel_width_y * 0.5_wp )
2084	tys_in = INT( ( ny + 1 ) * 0.5_wp * dy - &
2085	( tunnel_width_y * 0.5_wp - td ) )
2086	tye_in = INT( ( ny + 1 ) * 0.5_wp * dy + &
2087	( tunnel_width_y * 0.5_wp - td ) )
2088	ENDIF
2089
2090	topo = 0
2091	DO i = nxl, nxr
2092	DO j = nys, nyn
2093	!
2094	!-- Use heaviside function to model outer tunnel surface
2095	hv_out = th * 0.5_wp * &
2096	( ( SIGN( 1.0_wp, i * dx - txs_out ) + 1.0_wp ) &
2097	- ( SIGN( 1.0_wp, i * dx - txe_out ) + 1.0_wp ) )
2098
2099	hv_out = hv_out * 0.5_wp * &
2100	( ( SIGN( 1.0_wp, j * dy - tys_out ) + 1.0_wp ) &
2101	- ( SIGN( 1.0_wp, j * dy - tye_out ) + 1.0_wp ) )
2102	!
2103	!-- Use heaviside function to model inner tunnel surface
2104	hv_in = ( th - td ) * 0.5_wp * &
2105	( ( SIGN( 1.0_wp, i * dx - txs_in ) + 1.0_wp ) &
2106	- ( SIGN( 1.0_wp, i * dx - txe_in ) + 1.0_wp ) )
2107
2108	hv_in = hv_in * 0.5_wp * &
2109	( ( SIGN( 1.0_wp, j * dy - tys_in ) + 1.0_wp ) &
2110	- ( SIGN( 1.0_wp, j * dy - tye_in ) + 1.0_wp ) )
2111	!
2112	!-- Set flags at x-y-positions without any tunnel surface
2113	IF ( hv_out - hv_in == 0.0_wp ) THEN
2114	topo(nzb+1:nzt+1,j,i) = IBSET( topo(nzb+1:nzt+1,j,i), 0 )
2115	!
2116	!-- Set flags at x-y-positions with tunnel surfaces
2117	ELSE
2118	DO k = nzb + 1, nzt + 1
2119	!
2120	!-- Inner tunnel
2121	IF ( hv_out - hv_in == th ) THEN
2122	IF ( zw(k) <= hv_out ) THEN
2123	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
2124	ELSE
2125	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2126	ENDIF
2127	ENDIF
2128	!
2129	!-- Lateral tunnel walls
2130	IF ( hv_out - hv_in == td ) THEN
2131	IF ( zw(k) <= hv_in ) THEN
2132	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2133	ELSEIF ( zw(k) > hv_in .AND. zw(k) <= hv_out ) THEN
2134	topo(k,j,i) = IBCLR( topo(k,j,i), 0 )
2135	ELSEIF ( zw(k) > hv_out ) THEN
2136	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2137	ENDIF
2138	ENDIF
2139	ENDDO
2140	ENDIF
2141	ENDDO
2142	ENDDO
2143
2144	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2145	!
2146	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2147	!-- boundary conditions for topography.
2148	IF ( .NOT. bc_ns_cyc ) THEN
2149	IF ( nys == 0 ) THEN
2150	DO i = 1, nbgp
2151	topo(:,nys-i,:) = topo(:,nys,:)
2152	ENDDO
2153	ENDIF
2154	IF ( nyn == ny ) THEN
2155	DO i = 1, nbgp
2156	topo(:,nyn+i,:) = topo(:,nyn,:)
2157	ENDDO
2158	ENDIF
2159	ENDIF
2160	IF ( .NOT. bc_lr_cyc ) THEN
2161	IF ( nxl == 0 ) THEN
2162	DO i = 1, nbgp
2163	topo(:,:,nxl-i) = topo(:,:,nxl)
2164	ENDDO
2165	ENDIF
2166	IF ( nxr == nx ) THEN
2167	DO i = 1, nbgp
2168	topo(:,:,nxr+i) = topo(:,:,nxr)
2169	ENDDO
2170	ENDIF
2171	ENDIF
2172
2173	CASE ( 'read_from_file' )
2174	!
2175	!-- Note, topography information have been already read.
2176	!-- If required, further process topography, i.e. reference buildings on
2177	!-- top of orography and set temporary 3D topography array, which is
2178	!-- used later to set grid flags. Calling of this rouinte is also
2179	!-- required in case of ASCII input, even though no distinction between
2180	!-- terrain- and building height is made in this case.
2181	CALL process_topography( topo )
2182	!
2183	!-- Filter holes resolved by only one grid-point
2184	CALL filter_topography( topo )
2185	!
2186	!-- Exchange ghost-points, as well as add cyclic or Neumann boundary
2187	!-- conditions.
2188	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2189	!
2190	!-- Set lateral boundary conditions for topography on all ghost layers
2191	IF ( .NOT. bc_ns_cyc ) THEN
2192	IF ( nys == 0 ) THEN
2193	DO i = 1, nbgp
2194	topo(:,nys-i,:) = topo(:,nys,:)
2195	ENDDO
2196	ENDIF
2197	IF ( nyn == ny ) THEN
2198	DO i = 1, nbgp
2199	topo(:,nyn+i,:) = topo(:,nyn,:)
2200	ENDDO
2201	ENDIF
2202	ENDIF
2203
2204	IF ( .NOT. bc_lr_cyc ) THEN
2205	IF ( nxl == 0 ) THEN
2206	DO i = 1, nbgp
2207	topo(:,:,nxl-i) = topo(:,:,nxl)
2208	ENDDO
2209	ENDIF
2210	IF ( nxr == nx ) THEN
2211	DO i = 1, nbgp
2212	topo(:,:,nxr+i) = topo(:,:,nxr)
2213	ENDDO
2214	ENDIF
2215	ENDIF
2216
2217
2218	CASE DEFAULT
2219	!
2220	!-- The DEFAULT case is reached either if the parameter topography
2221	!-- contains a wrong character string or if the user has defined a special
2222	!-- case in the user interface. There, the subroutine user_init_grid
2223	!-- checks which of these two conditions applies.
2224	CALL user_init_grid( topo )
2225	CALL filter_topography( topo )
2226
2227	END SELECT
2228	!
2229	!-- Consistency checks and index array initialization are only required for
2230	!-- non-flat topography.
2231	IF ( TRIM( topography ) /= 'flat' ) THEN
2232	!
2233	!-- In case of non-flat topography, check whether the convention how to
2234	!-- define the topography grid has been set correctly, or whether the default
2235	!-- is applicable. If this is not possible, abort.
2236	IF ( TRIM( topography_grid_convention ) == ' ' ) THEN
2237	IF ( TRIM( topography ) /= 'single_building' .AND. &
2238	TRIM( topography ) /= 'single_street_canyon' .AND. &
2239	TRIM( topography ) /= 'tunnel' .AND. &
2240	TRIM( topography ) /= 'read_from_file') THEN
2241	!-- The default value is not applicable here, because it is only valid
2242	!-- for the four standard cases 'single_building',
2243	!-- 'single_street_canyon', 'tunnel' and 'read_from_file'
2244	!-- defined in init_grid.
2245	WRITE( message_string, * ) &
2246	'The value for "topography_grid_convention" ', &
2247	'is not set. Its default value is & only valid for ', &
2248	'"topography" = ''single_building'', ''tunnel'' ', &
2249	'''single_street_canyon'' & or ''read_from_file''.', &
2250	'& Choose ''cell_edge'' or ''cell_center''.'
2251	CALL message( 'init_grid', 'PA0239', 1, 2, 0, 6, 0 )
2252	ELSE
2253	!-- The default value is applicable here.
2254	!-- Set convention according to topography.
2255	IF ( TRIM( topography ) == 'single_building' .OR. &
2256	TRIM( topography ) == 'single_street_canyon' ) THEN
2257	topography_grid_convention = 'cell_edge'
2258	ELSEIF ( TRIM( topography ) == 'read_from_file' .OR. &
2259	TRIM( topography ) == 'tunnel') THEN
2260	topography_grid_convention = 'cell_center'
2261	ENDIF
2262	ENDIF
2263	ELSEIF ( TRIM( topography_grid_convention ) /= 'cell_edge' .AND. &
2264	TRIM( topography_grid_convention ) /= 'cell_center' ) THEN
2265	WRITE( message_string, * ) &
2266	'The value for "topography_grid_convention" is ', &
2267	'not recognized.& Choose ''cell_edge'' or ''cell_center''.'
2268	CALL message( 'init_grid', 'PA0240', 1, 2, 0, 6, 0 )
2269	ENDIF
2270
2271
2272	IF ( topography_grid_convention == 'cell_edge' ) THEN
2273	!
2274	!-- The array nzb_local as defined using the 'cell_edge' convention
2275	!-- describes the actual total size of topography which is defined at the
2276	!-- cell edges where u=0 on the topography walls in x-direction and v=0
2277	!-- on the topography walls in y-direction. However, PALM uses individual
2278	!-- arrays nzb_u\|v\|w\|s_inner\|outer that are based on nzb_s_inner.
2279	!-- Therefore, the extent of topography in nzb_local is now reduced by
2280	!-- 1dx at the E topography walls and by 1dy at the N topography walls
2281	!-- to form the basis for nzb_s_inner.
2282	!-- Note, the reverse memory access (i-j instead of j-i) is absolutely
2283	!-- required at this point.
2284	DO j = nys+1, nyn+1
2285	DO i = nxl-1, nxr
2286	DO k = nzb, nzt+1
2287	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2288	BTEST( topo(k,j,i+1), 0 ) ) &
2289	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2290	ENDDO
2291	ENDDO
2292	ENDDO
2293	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2294
2295	DO i = nxl, nxr+1
2296	DO j = nys-1, nyn
2297	DO k = nzb, nzt+1
2298	IF ( BTEST( topo(k,j,i), 0 ) .OR. &
2299	BTEST( topo(k,j+1,i), 0 ) ) &
2300	topo(k,j,i) = IBSET( topo(k,j,i), 0 )
2301	ENDDO
2302	ENDDO
2303	ENDDO
2304	CALL exchange_horiz_int( topo, nys, nyn, nxl, nxr, nzt, nbgp )
2305
2306	ENDIF
2307	ENDIF
2308
2309
2310	END SUBROUTINE init_topo
2311
2312	SUBROUTINE set_topo_flags(topo)
2313
2314	USE control_parameters, &
2315	ONLY: bc_lr_cyc, bc_ns_cyc, constant_flux_layer, &
2316	scalar_advec, topography, use_surface_fluxes, use_top_fluxes
2317
2318	USE indices, &
2319	ONLY: nbgp, nx, nxl, nxlg, nxr, nxrg, ny, nyn, nyng, nys, nysg, nzb, &
2320	nzt, topo_top_ind, wall_flags_0
2321
2322	USE kinds
2323
2324	IMPLICIT NONE
2325
2326	INTEGER(iwp) :: i !< index variable along x
2327	INTEGER(iwp) :: ibit !< integer bit position of topgraphy masking array
2328	INTEGER(iwp) :: j !< index variable along y
2329	INTEGER(iwp) :: k !< index variable along z
2330
2331	INTEGER(iwp), DIMENSION(nzb:nzt+1,nysg:nyng,nxlg:nxrg) :: topo !< input array for 3D topography and dummy array for setting "outer"-flags
2332
2333	ALLOCATE( wall_flags_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
2334	wall_flags_0 = 0
2335	!
2336	!-- Set-up topography flags. First, set flags only for s, u, v and w-grid.
2337	!-- Further special flags will be set in following loops.
2338	DO i = nxl, nxr
2339	DO j = nys, nyn
2340	DO k = nzb, nzt+1
2341	!
2342	!-- scalar grid
2343	IF ( BTEST( topo(k,j,i), 0 ) ) &
2344	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 0 )
2345	!
2346	!-- u grid
2347	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2348	BTEST( topo(k,j,i-1), 0 ) ) &
2349	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 1 )
2350	!
2351	!-- v grid
2352	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2353	BTEST( topo(k,j-1,i), 0 ) ) &
2354	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 2 )
2355
2356	ENDDO
2357
2358	DO k = nzb, nzt
2359	!
2360	!-- w grid
2361	IF ( BTEST( topo(k,j,i), 0 ) .AND. &
2362	BTEST( topo(k+1,j,i), 0 ) ) &
2363	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 3 )
2364	ENDDO
2365	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 3 )
2366
2367	ENDDO
2368	ENDDO
2369
2370	CALL exchange_horiz_int( wall_flags_0, nys, nyn, nxl, nxr, nzt, nbgp )
2371	!
2372	!-- Set outer array for scalars to mask near-surface grid points. Note, on
2373	!-- basis of flag 24 futher flags will be derived which are used to control
2374	!-- production of subgrid TKE production near walls.
2375	DO i = nxl, nxr
2376	DO j = nys, nyn
2377	DO k = nzb, nzt+1
2378	IF ( BTEST( wall_flags_0(k,j-1,i), 0 ) .AND. &
2379	BTEST( wall_flags_0(k,j+1,i), 0 ) .AND. &
2380	BTEST( wall_flags_0(k,j,i-1), 0 ) .AND. &
2381	BTEST( wall_flags_0(k,j,i+1), 0 ) .AND. &
2382	BTEST( wall_flags_0(k,j-1,i-1), 0 ) .AND. &
2383	BTEST( wall_flags_0(k,j+1,i-1), 0 ) .AND. &
2384	BTEST( wall_flags_0(k,j-1,i+1), 0 ) .AND. &
2385	BTEST( wall_flags_0(k,j+1,i+1), 0 ) ) &
2386	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 24 )
2387	ENDDO
2388	ENDDO
2389	ENDDO
2390	!
2391	!-- Set further special flags
2392	DO i = nxl, nxr
2393	DO j = nys, nyn
2394	DO k = nzb, nzt+1
2395	!
2396	!-- scalar grid, former nzb_diff_s_inner.
2397	!-- Note, use this flag also to mask topography in diffusion_u and
2398	!-- diffusion_v along the vertical direction. In case of
2399	!-- use_surface_fluxes, fluxes are calculated via MOST, else, simple
2400	!-- gradient approach is applied. Please note, in case of u- and v-
2401	!-- diffuison, a small error is made at edges (on the east side for u,
2402	!-- at the north side for v), since topography on scalar grid point
2403	!-- is used instead of topography on u/v-grid. As number of topography grid
2404	!-- points on uv-grid is different than s-grid, different number of
2405	!-- surface elements would be required. In order to avoid this,
2406	!-- treat edges (u(k,j,i+1)) simply by a gradient approach, i.e. these
2407	!-- points are not masked within diffusion_u. Tests had shown that the
2408	!-- effect on the flow is negligible.
2409	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2410	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2411	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 8 )
2412	ELSE
2413	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 8 )
2414	ENDIF
2415
2416	ENDDO
2417	!
2418	!-- Special flag to control vertical diffusion at model top - former
2419	!-- nzt_diff
2420	wall_flags_0(:,j,i) = IBSET( wall_flags_0(:,j,i), 9 )
2421	IF ( use_top_fluxes ) &
2422	wall_flags_0(nzt+1,j,i) = IBCLR( wall_flags_0(nzt+1,j,i), 9 )
2423
2424
2425	DO k = nzb+1, nzt
2426	!
2427	!-- Special flag on u grid, former nzb_u_inner + 1, required
2428	!-- for disturb_field and initialization. Do not disturb directly at
2429	!-- topography, as well as initialize u with zero one grid point outside
2430	!-- of topography.
2431	IF ( BTEST( wall_flags_0(k-1,j,i), 1 ) .AND. &
2432	BTEST( wall_flags_0(k,j,i), 1 ) .AND. &
2433	BTEST( wall_flags_0(k+1,j,i), 1 ) ) &
2434	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 20 )
2435	!
2436	!-- Special flag on v grid, former nzb_v_inner + 1, required
2437	!-- for disturb_field and initialization. Do not disturb directly at
2438	!-- topography, as well as initialize v with zero one grid point outside
2439	!-- of topography.
2440	IF ( BTEST( wall_flags_0(k-1,j,i), 2 ) .AND. &
2441	BTEST( wall_flags_0(k,j,i), 2 ) .AND. &
2442	BTEST( wall_flags_0(k+1,j,i), 2 ) ) &
2443	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 21 )
2444	!
2445	!-- Special flag on scalar grid, former nzb_s_inner+1. Used for
2446	!-- lpm_sgs_tke
2447	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2448	BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2449	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2450	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 25 )
2451	!
2452	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2453	!-- in production_e
2454	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2455	IF ( BTEST( wall_flags_0(k,j,i), 24 ) .AND. &
2456	BTEST( wall_flags_0(k-1,j,i), 24 ) .AND. &
2457	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2458	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 29 )
2459	ELSE
2460	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2461	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 29 )
2462	ENDIF
2463	!
2464	!-- Special flag on scalar grid, nzb_diff_s_outer - 1, required in
2465	!-- in production_e
2466	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2467	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2468	BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2469	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2470	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 30 )
2471	ELSE
2472	IF ( BTEST( wall_flags_0(k,j,i), 0 ) ) &
2473	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 30 )
2474	ENDIF
2475	ENDDO
2476	!
2477	!-- Flags indicating downward facing walls
2478	DO k = nzb+1, nzt
2479	!
2480	!-- Scalar grid
2481	IF ( BTEST( wall_flags_0(k-1,j,i), 0 ) .AND. &
2482	.NOT. BTEST( wall_flags_0(k,j,i), 0 ) ) &
2483	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 13 )
2484	!
2485	!-- Downward facing wall on u grid
2486	IF ( BTEST( wall_flags_0(k-1,j,i), 1 ) .AND. &
2487	.NOT. BTEST( wall_flags_0(k,j,i), 1 ) ) &
2488	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 15 )
2489	!
2490	!-- Downward facing wall on v grid
2491	IF ( BTEST( wall_flags_0(k-1,j,i), 2 ) .AND. &
2492	.NOT. BTEST( wall_flags_0(k,j,i), 2 ) ) &
2493	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 17 )
2494	!
2495	!-- Downward facing wall on w grid
2496	IF ( BTEST( wall_flags_0(k-1,j,i), 3 ) .AND. &
2497	.NOT. BTEST( wall_flags_0(k,j,i), 3 ) ) &
2498	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 19 )
2499	ENDDO
2500	!
2501	!-- Flags indicating upward facing walls
2502	DO k = nzb, nzt
2503	!
2504	!-- Upward facing wall on scalar grid
2505	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2506	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2507	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 12 )
2508	!
2509	!-- Upward facing wall on u grid
2510	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 1 ) .AND. &
2511	BTEST( wall_flags_0(k+1,j,i), 1 ) ) &
2512	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 14 )
2513
2514	!
2515	!-- Upward facing wall on v grid
2516	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 2 ) .AND. &
2517	BTEST( wall_flags_0(k+1,j,i), 2 ) ) &
2518	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 16 )
2519
2520	!
2521	!-- Upward facing wall on w grid
2522	IF ( .NOT. BTEST( wall_flags_0(k,j,i), 3 ) .AND. &
2523	BTEST( wall_flags_0(k+1,j,i), 3 ) ) &
2524	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 18 )
2525	!
2526	!-- Special flag on scalar grid, former nzb_s_inner
2527	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .OR. &
2528	BTEST( wall_flags_0(k,j,i), 12 ) .OR. &
2529	BTEST( wall_flags_0(k,j,i), 13 ) ) &
2530	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 22 )
2531	!
2532	!-- Special flag on scalar grid, nzb_diff_s_inner - 1, required for
2533	!-- flow_statistics
2534	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
2535	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. &
2536	BTEST( wall_flags_0(k+1,j,i), 0 ) ) &
2537	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 23 )
2538	ELSE
2539	IF ( BTEST( wall_flags_0(k,j,i), 22 ) ) &
2540	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 23 )
2541	ENDIF
2542
2543
2544	ENDDO
2545	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 22 )
2546	wall_flags_0(nzt+1,j,i) = IBSET( wall_flags_0(nzt+1,j,i), 23 )
2547	!
2548	!-- Set flags indicating that topography is close by in horizontal
2549	!-- direction, i.e. flags that infold the topography. These will be used
2550	!-- to set advection flags for passive scalars, where due to large
2551	!-- gradients near buildings stationary numerical oscillations can produce
2552	!-- unrealistically high concentrations. This is only necessary if
2553	!-- WS-scheme is applied for scalar advection. Note, these flags will be
2554	!-- only used for passive scalars such as chemical species or aerosols.
2555	IF ( scalar_advec == 'ws-scheme' ) THEN
2556	DO k = nzb, nzt
2557	IF ( BTEST( wall_flags_0(k,j,i), 0 ) .AND. ( &
2558	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-1), 0 ) ) .OR.&
2559	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-2), 0 ) ) .OR.&
2560	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i-3), 0 ) ) .OR.&
2561	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+1), 0 ) ) .OR.&
2562	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+2), 0 ) ) .OR.&
2563	ANY( .NOT. BTEST( wall_flags_0(k,j-3:j+3,i+3), 0 ) ) .OR.&
2564	ANY( .NOT. BTEST( wall_flags_0(k,j-1,i-3:i+3), 0 ) ) .OR.&
2565	ANY( .NOT. BTEST( wall_flags_0(k,j-2,i-3:i+3), 0 ) ) .OR.&
2566	ANY( .NOT. BTEST( wall_flags_0(k,j-3,i-3:i+3), 0 ) ) .OR.&
2567	ANY( .NOT. BTEST( wall_flags_0(k,j+1,i-3:i+3), 0 ) ) .OR.&
2568	ANY( .NOT. BTEST( wall_flags_0(k,j+2,i-3:i+3), 0 ) ) .OR.&
2569	ANY( .NOT. BTEST( wall_flags_0(k,j+3,i-3:i+3), 0 ) ) &
2570	) ) &
2571	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 31 )
2572
2573	ENDDO
2574	ENDIF
2575	ENDDO
2576	ENDDO
2577	!
2578	!-- Finally, set identification flags indicating natural terrain or buildings.
2579	!-- Natural terrain grid points. Information on the type of the surface is
2580	!-- stored in bit 1 of 3D Integer array topo. However, this bit is only set
2581	!-- when topography is read from file. In order to run the land-surface model
2582	!-- also without topography information, set bit 1 explicitely in this case.
2583	!--
2584	!-- Natural terrain grid points
2585	!-- If no topography is initialized, the land-surface is at k = nzb.
2586	IF ( TRIM( topography ) /= 'read_from_file' ) THEN
2587	wall_flags_0(nzb,:,:) = IBSET( wall_flags_0(nzb,:,:), 5 )
2588	ELSE
2589	DO i = nxl, nxr
2590	DO j = nys, nyn
2591	DO k = nzb, nzt+1
2592	!
2593	!-- Natural terrain grid point
2594	IF ( BTEST( topo(k,j,i), 1 ) ) &
2595	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 5 )
2596	ENDDO
2597	ENDDO
2598	ENDDO
2599	ENDIF
2600	!
2601	!-- Building grid points.
2602	DO i = nxl, nxr
2603	DO j = nys, nyn
2604	DO k = nzb, nzt+1
2605	IF ( BTEST( topo(k,j,i), 2 ) ) &
2606	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 6 )
2607	ENDDO
2608	ENDDO
2609	ENDDO
2610	!
2611	!-- Set flag 4, indicating new topography grid points due to filtering.
2612	DO i = nxl, nxr
2613	DO j = nys, nyn
2614	DO k = nzb, nzt+1
2615	IF ( BTEST( topo(k,j,i), 4 ) ) &
2616	wall_flags_0(k,j,i) = IBSET( wall_flags_0(k,j,i), 4 )
2617	ENDDO
2618	ENDDO
2619	ENDDO
2620	!
2621	!-- Exchange ghost points for wall flags
2622	CALL exchange_horiz_int( wall_flags_0, nys, nyn, nxl, nxr, nzt, nbgp )
2623	!
2624	!-- Set boundary conditions also for flags. Can be interpreted as Neumann
2625	!-- boundary conditions for topography.
2626	IF ( .NOT. bc_ns_cyc ) THEN
2627	IF ( nys == 0 ) THEN
2628	DO i = 1, nbgp
2629	wall_flags_0(:,nys-i,:) = wall_flags_0(:,nys,:)
2630	ENDDO
2631	ENDIF
2632	IF ( nyn == ny ) THEN
2633	DO i = 1, nbgp
2634	wall_flags_0(:,nyn+i,:) = wall_flags_0(:,nyn,:)
2635	ENDDO
2636	ENDIF
2637	ENDIF
2638	IF ( .NOT. bc_lr_cyc ) THEN
2639	IF ( nxl == 0 ) THEN
2640	DO i = 1, nbgp
2641	wall_flags_0(:,:,nxl-i) = wall_flags_0(:,:,nxl)
2642	ENDDO
2643	ENDIF
2644	IF ( nxr == nx ) THEN
2645	DO i = 1, nbgp
2646	wall_flags_0(:,:,nxr+i) = wall_flags_0(:,:,nxr)
2647	ENDDO
2648	ENDIF
2649	ENDIF
2650	!
2651	!-- Pre-calculate topography top indices (former get_topography_top_index
2652	!-- function)
2653	ALLOCATE( topo_top_ind(nysg:nyng,nxlg:nxrg,0:4) )
2654	!
2655	!-- Uppermost topography index on scalar grid
2656	ibit = 12
2657	topo_top_ind(:,:,0) = MAXLOC( &
2658	MERGE( 1, 0, &
2659	BTEST( wall_flags_0(:,:,:), ibit ) &
2660	), DIM = 1 &
2661	) - 1
2662	!
2663	!-- Uppermost topography index on u grid
2664	ibit = 14
2665	topo_top_ind(:,:,1) = MAXLOC( &
2666	MERGE( 1, 0, &
2667	BTEST( wall_flags_0(:,:,:), ibit ) &
2668	), DIM = 1 &
2669	) - 1
2670	!
2671	!-- Uppermost topography index on v grid
2672	ibit = 16
2673	topo_top_ind(:,:,2) = MAXLOC( &
2674	MERGE( 1, 0, &
2675	BTEST( wall_flags_0(:,:,:), ibit ) &
2676	), DIM = 1 &
2677	) - 1
2678	!
2679	!-- Uppermost topography index on w grid
2680	ibit = 18
2681	topo_top_ind(:,:,3) = MAXLOC( &
2682	MERGE( 1, 0, &
2683	BTEST( wall_flags_0(:,:,:), ibit ) &
2684	), DIM = 1 &
2685	) - 1
2686	!
2687	!-- Uppermost topography index on scalar outer grid
2688	ibit = 24
2689	topo_top_ind(:,:,4) = MAXLOC( &
2690	MERGE( 1, 0, &
2691	BTEST( wall_flags_0(:,:,:), ibit ) &
2692	), DIM = 1 &
2693	) - 1
2694
2695	END SUBROUTINE set_topo_flags
2696
2697
2698

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