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source: palm/trunk/SOURCE/init_grid.f90 @ 2016

Last change on this file since 2016 was 2001, checked in by knoop, 8 years ago
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[1682]	1	!> @file init_grid.f90
[2000]	2	!------------------------------------------------------------------------------!
[1036]	3	! This file is part of PALM.
	4	!
[2000]	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.
[1036]	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	!
[1818]	17	! Copyright 1997-2016 Leibniz Universitaet Hannover
[2000]	18	!------------------------------------------------------------------------------!
[1036]	19	!
[254]	20	! Current revisions:
[1]	21	! -----------------
[1969]	22	!
[2001]	23	!
[1969]	24	! Former revisions:
	25	! -----------------
	26	! $Id: init_grid.f90 2001 2016-08-20 18:41:22Z lvollmer $
	27	!
[2001]	28	! 2000 2016-08-20 18:09:15Z knoop
	29	! Forced header and separation lines into 80 columns
	30	!
[1995]	31	! 1994 2016-08-15 09:52:21Z suehring
	32	! Bugfix in definition of generic topography
	33	!
[1983]	34	! 1982 2016-08-01 11:04:48Z suehring
	35	! Bugfix concering consistency check for topography
	36	!
[1969]	37	! 1968 2016-07-18 12:01:49Z suehring
[1968]	38	! Changed: PE-wise reading of topography file in order to avoid global definition
	39	! of arrays nzb_local and nzb_tmp. Thereby, topography definition for single
	40	! buildings and street canyons has changed, as well as flag setting for
	41	! multigrid scheme.
	42	!
	43	! Bugfix in checking l_grid anisotropy.
	44	! Simplify initial computation of lwall and vertical_influence, i.e. remove
	45	! nzb_s_inner as it is still zero at this point.
[1932]	46	!
[1943]	47	! 1942 2016-06-14 12:18:18Z suehring
	48	! Topography filter implemented to fill holes resolved by only one grid point.
	49	! Initialization of flags for ws-scheme moved to advec_ws.
	50	!
[1932]	51	! 1931 2016-06-10 12:06:59Z suehring
	52	! Rename multigrid into multigrid_noopt and multigrid_fast into multigrid
	53	!
[1911]	54	! 1910 2016-05-26 06:49:46Z raasch
	55	! Bugfix: if topography is read from file, Neumann conditions are used for the
	56	! nzb_local array (instead of cyclic conditions) in case that non-cyclic
	57	! boundary conditions are switched on for the run
	58	!
[1903]	59	! 1902 2016-05-09 11:18:56Z suehring
[1910]	60	! Set topography flags for multigrid solver only (not for multigrid_fast)
[1903]	61	!
[1887]	62	! 1886 2016-04-21 11:20:47Z suehring
	63	! Bugfix: setting advection flags near walls
	64	! reformulated index values for nzb_v_inner
	65	! variable discriptions added in declaration block
	66	!
[1846]	67	! 1845 2016-04-08 08:29:13Z raasch
	68	! nzb_2d removed
	69	!
[1805]	70	! 1804 2016-04-05 16:30:18Z maronga
	71	! Removed code for parameter file check (__check)
	72	!
[1780]	73	! 1779 2016-03-03 08:01:28Z raasch
	74	! coupling_char is trimmed at every place it occurs, because it can have
	75	! different length now
	76	!
[1763]	77	! 1762 2016-02-25 12:31:13Z hellstea
	78	! Introduction of nested domain feature
	79	!
[1744]	80	! 1743 2016-01-13 10:23:51Z raasch
	81	! Bugfix for calculation of nzb_s_outer and nzb_u_outer at north boundary of
	82	! total domain
	83	!
[1692]	84	! 1691 2015-10-26 16:17:44Z maronga
	85	! Renamed prandtl_layer to constant_flux_layer.
	86	!
[1683]	87	! 1682 2015-10-07 23:56:08Z knoop
	88	! Code annotations made doxygen readable
	89	!
[1678]	90	! 1677 2015-10-02 13:25:23Z boeske
	91	! Bugfix: Ghost points are included in wall_flags_0 and wall_flags_00
	92	!
[1676]	93	! 1675 2015-10-02 08:28:59Z gronemeier
	94	! Bugfix: Definition of topography grid levels
	95	!
[1662]	96	! 1660 2015-09-21 08:15:16Z gronemeier
	97	! Bugfix: Definition of topography grid levels if vertical grid stretching
	98	! starts below the maximum topography height.
	99	!
[1581]	100	! 1580 2015-04-10 13:43:49Z suehring
	101	! Bugfix: setting flags for 5th order scheme near buildings
	102	!
[1576]	103	! 1575 2015-03-27 09:56:27Z raasch
	104	! adjustments for psolver-queries
	105	!
[1558]	106	! 1557 2015-03-05 16:43:04Z suehring
	107	! Adjustment for monotoinic limiter
	108	!
[1419]	109	! 1418 2014-06-06 13:05:08Z fricke
	110	! Bugfix: Change if-condition for stretched grid in the ocean, with the old
	111	! condition and a negative value for dz_stretch_level the condition
	112	! was always true for the whole model domain
	113	!
[1410]	114	! 1409 2014-05-23 12:11:32Z suehring
	115	! Bugfix: set wall_flags_0 at inflow and outflow boundary also for i <= nxlu
	116	! j <= nysv
	117	!
[1354]	118	! 1353 2014-04-08 15:21:23Z heinze
	119	! REAL constants provided with KIND-attribute
	120	!
[1323]	121	! 1322 2014-03-20 16:38:49Z raasch
	122	! REAL constants defined as wp-kind
	123	!
[1321]	124	! 1320 2014-03-20 08:40:49Z raasch
[1320]	125	! ONLY-attribute added to USE-statements,
	126	! kind-parameters added to all INTEGER and REAL declaration statements,
	127	! kinds are defined in new module kinds,
	128	! revision history before 2012 removed,
	129	! comment fields (!:) to be used for variable explanations added to
	130	! all variable declaration statements
[1321]	131	!
[1222]	132	! 1221 2013-09-10 08:59:13Z raasch
	133	! wall_flags_00 introduced to hold bits 32-63,
	134	! additional 3D-flag arrays for replacing the 2D-index array nzb_s_inner in
	135	! loops optimized for openACC (pres + flow_statistics)
	136	!
[1093]	137	! 1092 2013-02-02 11:24:22Z raasch
	138	! unused variables removed
	139	!
[1070]	140	! 1069 2012-11-28 16:18:43Z maronga
[1779]	141	! bugfix: added coupling_char to TOPOGRAPHY_DATA to allow topography in the
	142	! ocean model in case of coupled runs
[1070]	143	!
[1037]	144	! 1036 2012-10-22 13:43:42Z raasch
	145	! code put under GPL (PALM 3.9)
	146	!
[1017]	147	! 1015 2012-09-27 09:23:24Z raasch
	148	! lower index for calculating wall_flags_0 set to nzb_w_inner instead of
	149	! nzb_w_inner+1
	150	!
[997]	151	! 996 2012-09-07 10:41:47Z raasch
	152	! little reformatting
	153	!
[979]	154	! 978 2012-08-09 08:28:32Z fricke
	155	! Bugfix: nzb_max is set to nzt at non-cyclic lateral boundaries
	156	! Bugfix: Set wall_flags_0 for inflow boundary
	157	!
[928]	158	! 927 2012-06-06 19:15:04Z raasch
	159	! Wall flags are not set for multigrid method in case of masking method
	160	!
[865]	161	! 864 2012-03-27 15:10:33Z gryschka
[927]	162	! In case of ocean and Dirichlet bottom bc for u and v dzu_mg and ddzu_pres
	163	! were not correctly defined for k=1.
[865]	164	!
[863]	165	! 861 2012-03-26 14:18:34Z suehring
[861]	166	! Set wall_flags_0. The array is needed for degradation in ws-scheme near walls,
	167	! inflow and outflow boundaries as well as near the bottom and the top of the
[863]	168	! model domain.!
[861]	169	! Initialization of nzb_s_inner and nzb_w_inner.
	170	! gls has to be at least nbgp to do not exceed the array bounds of nzb_local
	171	! while setting wall_flags_0
	172	!
[844]	173	! 843 2012-02-29 15:16:21Z gryschka
	174	! In case of ocean and dirichlet bc for u and v at the bottom
	175	! the first u-level ist defined at same height as the first w-level
	176	!
[819]	177	! 818 2012-02-08 16:11:23Z maronga
	178	! Bugfix: topo_height is only required if topography is used. It is thus now
	179	! allocated in the topography branch
	180	!
[810]	181	! 809 2012-01-30 13:32:58Z maronga
	182	! Bugfix: replaced .AND. and .NOT. with && and ! in the preprocessor directives
	183	!
[808]	184	! 807 2012-01-25 11:53:51Z maronga
	185	! New cpp directive "__check" implemented which is used by check_namelist_files
	186	!
[1]	187	! Revision 1.1 1997/08/11 06:17:45 raasch
	188	! Initial revision (Testversion)
	189	!
	190	!
	191	! Description:
	192	! ------------
[1682]	193	!> Creating grid depending constants
[1]	194	!------------------------------------------------------------------------------!
[1682]	195	SUBROUTINE init_grid
	196
[1942]	197	USE advec_ws, &
	198	ONLY: ws_init_flags
[1]	199
[1320]	200	USE arrays_3d, &
	201	ONLY: dd2zu, ddzu, ddzu_pres, ddzw, dzu, dzu_mg, dzw, dzw_mg, f1_mg, &
	202	f2_mg, f3_mg, l_grid, l_wall, zu, zw
	203
[1353]	204	USE control_parameters, &
[1910]	205	ONLY: bc_lr_cyc, bc_ns_cyc, building_height, building_length_x, &
[1320]	206	building_length_y, building_wall_left, building_wall_south, &
	207	canyon_height, canyon_wall_left, canyon_wall_south, &
[1691]	208	canyon_width_x, canyon_width_y, constant_flux_layer, &
	209	coupling_char, dp_level_ind_b, dz, dz_max, dz_stretch_factor, &
[1968]	210	dz_stretch_level, dz_stretch_level_index, grid_level, ibc_uv_b, &
	211	io_blocks, io_group, inflow_l, inflow_n, inflow_r, inflow_s, &
[1691]	212	masking_method, maximum_grid_level, message_string, &
[1942]	213	momentum_advec, nest_domain, ocean, outflow_l, outflow_n, &
[1762]	214	outflow_r, outflow_s, psolver, scalar_advec, topography, &
[1691]	215	topography_grid_convention, use_surface_fluxes, use_top_fluxes, &
	216	wall_adjustment_factor
[1320]	217
	218	USE grid_variables, &
	219	ONLY: ddx, ddx2, ddx2_mg, ddy, ddy2, ddy2_mg, dx, dx2, dy, dy2, fwxm, &
	220	fwxp, fwym, fwyp, fxm, fxp, fym, fyp, wall_e_x, wall_e_y, &
	221	wall_u, wall_v, wall_w_x, wall_w_y, zu_s_inner, zw_w_inner
	222
	223	USE indices, &
[1942]	224	ONLY: flags, nbgp, nx, nxl, nxlg, nxl_mg, nxr, nxrg, nxr_mg, &
	225	ny, nyn, nyng, nyn_mg, nys, nys_mg, nysg, nz, nzb, &
[1845]	226	nzb_diff, nzb_diff_s_inner, nzb_diff_s_outer, nzb_diff_u, &
	227	nzb_diff_v, nzb_max, nzb_s_inner, nzb_s_outer, nzb_u_inner, &
	228	nzb_u_outer, nzb_v_inner, nzb_v_outer, nzb_w_inner, &
	229	nzb_w_outer, nzt, nzt_diff, nzt_mg, rflags_invers, &
[1320]	230	rflags_s_inner, wall_flags_0, wall_flags_00, wall_flags_1, &
	231	wall_flags_10, wall_flags_2, wall_flags_3, wall_flags_4, &
	232	wall_flags_5, wall_flags_6, wall_flags_7, wall_flags_8, &
	233	wall_flags_9
	234
	235	USE kinds
	236
[1]	237	USE pegrid
	238
	239	IMPLICIT NONE
	240
[1968]	241	INTEGER(iwp) :: bh !< temporary vertical index of building height
	242	INTEGER(iwp) :: blx !< grid point number of building size along x
	243	INTEGER(iwp) :: bly !< grid point number of building size along y
	244	INTEGER(iwp) :: bxl !< index for left building wall
	245	INTEGER(iwp) :: bxr !< index for right building wall
	246	INTEGER(iwp) :: byn !< index for north building wall
	247	INTEGER(iwp) :: bys !< index for south building wall
	248	INTEGER(iwp) :: ch !< temporary vertical index for canyon height
	249	INTEGER(iwp) :: cwx !< grid point number of canyon size along x
	250	INTEGER(iwp) :: cwy !< grid point number of canyon size along y
	251	INTEGER(iwp) :: cxl !< index for left canyon wall
	252	INTEGER(iwp) :: cxr !< index for right canyon wall
	253	INTEGER(iwp) :: cyn !< index for north canyon wall
	254	INTEGER(iwp) :: cys !< index for south canyon wall
	255	INTEGER(iwp) :: i !< index variable along x
	256	INTEGER(iwp) :: ii !< loop variable for reading topography file
	257	INTEGER(iwp) :: inc !< incremental parameter for coarsening grid level
	258	INTEGER(iwp) :: j !< index variable along y
	259	INTEGER(iwp) :: k !< index variable along z
	260	INTEGER(iwp) :: l !< loop variable
	261	INTEGER(iwp) :: nxl_l !< index of left PE boundary for multigrid level
	262	INTEGER(iwp) :: nxr_l !< index of right PE boundary for multigrid level
	263	INTEGER(iwp) :: nyn_l !< index of north PE boundary for multigrid level
	264	INTEGER(iwp) :: nys_l !< index of south PE boundary for multigrid level
	265	INTEGER(iwp) :: nzb_local_max !< vertical grid index of maximum topography height
	266	INTEGER(iwp) :: nzb_local_min !< vertical grid index of minimum topography height
	267	INTEGER(iwp) :: nzb_si !< dummy index for local nzb_s_inner
	268	INTEGER(iwp) :: nzt_l !< index of top PE boundary for multigrid level
	269	INTEGER(iwp) :: num_hole !< number of holes (in topography) resolved by only one grid point
	270	INTEGER(iwp) :: num_hole_l !< number of holes (in topography) resolved by only one grid point on local PE
	271	INTEGER(iwp) :: num_wall !< number of surrounding vertical walls for a single grid point
	272	INTEGER(iwp) :: skip_n_rows !< counting variable to skip rows while reading topography file
	273	INTEGER(iwp) :: vi !< dummy for vertical influence
[1]	274
[1886]	275	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: &
[1931]	276	vertical_influence !< number of vertical grid points above obstacle where adjustment of near-wall mixing length is required
[1886]	277
[1968]	278	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: corner_nl !< index of north-left corner location to limit near-wall mixing length
	279	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: corner_nr !< north-right
	280	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: corner_sl !< south-left
	281	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: corner_sr !< south-right
	282	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_local !< index for topography top at cell-center
	283	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: nzb_tmp !< dummy to calculate topography indices on u- and v-grid
	284	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: wall_l !< distance to adjacent left-facing wall
	285	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: wall_n !< north-facing
	286	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: wall_r !< right-facing
	287	INTEGER(iwp), DIMENSION(:,:), ALLOCATABLE :: wall_s !< right-facing
[1]	288
[1968]	289	REAL(wp) :: dum !< dummy variable to skip columns while reading topography file
[1886]	290	REAL(wp) :: dx_l !< grid spacing along x on different multigrid level
	291	REAL(wp) :: dy_l !< grid spacing along y on different multigrid level
	292	REAL(wp) :: dz_stretched !< stretched vertical grid spacing
[861]	293
[1968]	294	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: topo_height !< input variable for topography height
	295	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: zu_s_inner_l !< dummy array on global scale to write topography output array
	296	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: zw_w_inner_l !< dummy array on global scale to write topography output array
[1]	297
[667]	298
[1]	299	!
[709]	300	!-- Calculation of horizontal array bounds including ghost layers
[667]	301	nxlg = nxl - nbgp
	302	nxrg = nxr + nbgp
	303	nysg = nys - nbgp
	304	nyng = nyn + nbgp
[709]	305
[667]	306	!
[1]	307	!-- Allocate grid arrays
[1353]	308	ALLOCATE( ddzu(1:nzt+1), ddzw(1:nzt+1), dd2zu(1:nzt), dzu(1:nzt+1), &
[667]	309	dzw(1:nzt+1), l_grid(1:nzt), zu(nzb:nzt+1), zw(nzb:nzt+1) )
[1]	310
	311	!
	312	!-- Compute height of u-levels from constant grid length and dz stretch factors
[1353]	313	IF ( dz == -1.0_wp ) THEN
[254]	314	message_string = 'missing dz'
	315	CALL message( 'init_grid', 'PA0200', 1, 2, 0, 6, 0 )
[1353]	316	ELSEIF ( dz <= 0.0_wp ) THEN
[254]	317	WRITE( message_string, * ) 'dz=',dz,' <= 0.0'
	318	CALL message( 'init_grid', 'PA0201', 1, 2, 0, 6, 0 )
[1]	319	ENDIF
[94]	320
[1]	321	!
[94]	322	!-- Define the vertical grid levels
	323	IF ( .NOT. ocean ) THEN
	324	!
	325	!-- Grid for atmosphere with surface at z=0 (k=0, w-grid).
[843]	326	!-- The second u-level (k=1) corresponds to the top of the
[94]	327	!-- Prandtl-layer.
[667]	328
	329	IF ( ibc_uv_b == 0 .OR. ibc_uv_b == 2 ) THEN
[1353]	330	zu(0) = 0.0_wp
	331	! zu(0) = - dz * 0.5_wp
[667]	332	ELSE
[1353]	333	zu(0) = - dz * 0.5_wp
[667]	334	ENDIF
[1353]	335	zu(1) = dz * 0.5_wp
[1]	336
[94]	337	dz_stretch_level_index = nzt+1
	338	dz_stretched = dz
	339	DO k = 2, nzt+1
	340	IF ( dz_stretch_level <= zu(k-1) .AND. dz_stretched < dz_max ) THEN
	341	dz_stretched = dz_stretched * dz_stretch_factor
	342	dz_stretched = MIN( dz_stretched, dz_max )
	343	IF ( dz_stretch_level_index == nzt+1 ) dz_stretch_level_index = k-1
	344	ENDIF
	345	zu(k) = zu(k-1) + dz_stretched
	346	ENDDO
[1]	347
	348	!
[94]	349	!-- Compute the w-levels. They are always staggered half-way between the
[843]	350	!-- corresponding u-levels. In case of dirichlet bc for u and v at the
	351	!-- ground the first u- and w-level (k=0) are defined at same height (z=0).
	352	!-- The top w-level is extrapolated linearly.
[1353]	353	zw(0) = 0.0_wp
[94]	354	DO k = 1, nzt
[1353]	355	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
[94]	356	ENDDO
[1353]	357	zw(nzt+1) = zw(nzt) + 2.0_wp * ( zu(nzt+1) - zw(nzt) )
[1]	358
[94]	359	ELSE
[1]	360	!
[843]	361	!-- Grid for ocean with free water surface is at k=nzt (w-grid).
	362	!-- In case of neumann bc at the ground the first first u-level (k=0) lies
	363	!-- below the first w-level (k=0). In case of dirichlet bc the first u- and
	364	!-- w-level are defined at same height, but staggered from the second level.
	365	!-- The second u-level (k=1) corresponds to the top of the Prandtl-layer.
[1353]	366	zu(nzt+1) = dz * 0.5_wp
	367	zu(nzt) = - dz * 0.5_wp
[94]	368
	369	dz_stretch_level_index = 0
	370	dz_stretched = dz
	371	DO k = nzt-1, 0, -1
[1418]	372	!
	373	!-- The default value of dz_stretch_level is positive, thus the first
	374	!-- condition is always true. Hence, the second condition is necessary.
	375	IF ( dz_stretch_level >= zu(k+1) .AND. dz_stretch_level <= 0.0 &
	376	.AND. dz_stretched < dz_max ) THEN
[94]	377	dz_stretched = dz_stretched * dz_stretch_factor
	378	dz_stretched = MIN( dz_stretched, dz_max )
	379	IF ( dz_stretch_level_index == 0 ) dz_stretch_level_index = k+1
	380	ENDIF
	381	zu(k) = zu(k+1) - dz_stretched
	382	ENDDO
	383
	384	!
	385	!-- Compute the w-levels. They are always staggered half-way between the
[843]	386	!-- corresponding u-levels, except in case of dirichlet bc for u and v
	387	!-- at the ground. In this case the first u- and w-level are defined at
	388	!-- same height. The top w-level (nzt+1) is not used but set for
	389	!-- consistency, since w and all scalar variables are defined up tp nzt+1.
[94]	390	zw(nzt+1) = dz
[1353]	391	zw(nzt) = 0.0_wp
[94]	392	DO k = 0, nzt
[1353]	393	zw(k) = ( zu(k) + zu(k+1) ) * 0.5_wp
[94]	394	ENDDO
	395
[843]	396	!
	397	!-- In case of dirichlet bc for u and v the first u- and w-level are defined
	398	!-- at same height.
	399	IF ( ibc_uv_b == 0 ) THEN
	400	zu(0) = zw(0)
	401	ENDIF
	402
[94]	403	ENDIF
	404
	405	!
[1]	406	!-- Compute grid lengths.
	407	DO k = 1, nzt+1
	408	dzu(k) = zu(k) - zu(k-1)
[1353]	409	ddzu(k) = 1.0_wp / dzu(k)
[1]	410	dzw(k) = zw(k) - zw(k-1)
[1353]	411	ddzw(k) = 1.0_wp / dzw(k)
[1]	412	ENDDO
	413
	414	DO k = 1, nzt
[1353]	415	dd2zu(k) = 1.0_wp / ( dzu(k) + dzu(k+1) )
[1]	416	ENDDO
[667]	417
	418	!
[709]	419	!-- The FFT- SOR-pressure solvers assume grid spacings of a staggered grid
	420	!-- everywhere. For the actual grid, the grid spacing at the lowest level
	421	!-- is only dz/2, but should be dz. Therefore, an additional array
	422	!-- containing with appropriate grid information is created for these
	423	!-- solvers.
[1575]	424	IF ( psolver(1:9) /= 'multigrid' ) THEN
[667]	425	ALLOCATE( ddzu_pres(1:nzt+1) )
	426	ddzu_pres = ddzu
[864]	427	ddzu_pres(1) = ddzu_pres(2) ! change for lowest level
[667]	428	ENDIF
[1]	429
	430	!
	431	!-- In case of multigrid method, compute grid lengths and grid factors for the
	432	!-- grid levels
[1575]	433	IF ( psolver(1:9) == 'multigrid' ) THEN
[1]	434
	435	ALLOCATE( ddx2_mg(maximum_grid_level), ddy2_mg(maximum_grid_level), &
	436	dzu_mg(nzb+1:nzt+1,maximum_grid_level), &
	437	dzw_mg(nzb+1:nzt+1,maximum_grid_level), &
	438	f1_mg(nzb+1:nzt,maximum_grid_level), &
	439	f2_mg(nzb+1:nzt,maximum_grid_level), &
	440	f3_mg(nzb+1:nzt,maximum_grid_level) )
	441
	442	dzu_mg(:,maximum_grid_level) = dzu
[667]	443	!
[864]	444	!-- Next line to ensure an equally spaced grid.
	445	dzu_mg(1,maximum_grid_level) = dzu(2)
[709]	446
[1]	447	dzw_mg(:,maximum_grid_level) = dzw
	448	nzt_l = nzt
	449	DO l = maximum_grid_level-1, 1, -1
[1353]	450	dzu_mg(nzb+1,l) = 2.0_wp * dzu_mg(nzb+1,l+1)
	451	dzw_mg(nzb+1,l) = 2.0_wp * dzw_mg(nzb+1,l+1)
[1]	452	nzt_l = nzt_l / 2
	453	DO k = 2, nzt_l+1
	454	dzu_mg(k,l) = dzu_mg(2k-2,l+1) + dzu_mg(2k-1,l+1)
	455	dzw_mg(k,l) = dzw_mg(2k-2,l+1) + dzw_mg(2k-1,l+1)
	456	ENDDO
	457	ENDDO
	458
	459	nzt_l = nzt
	460	dx_l = dx
	461	dy_l = dy
	462	DO l = maximum_grid_level, 1, -1
[1353]	463	ddx2_mg(l) = 1.0_wp / dx_l**2
	464	ddy2_mg(l) = 1.0_wp / dy_l**2
[1]	465	DO k = nzb+1, nzt_l
[1353]	466	f2_mg(k,l) = 1.0_wp / ( dzu_mg(k+1,l) * dzw_mg(k,l) )
	467	f3_mg(k,l) = 1.0_wp / ( dzu_mg(k,l) * dzw_mg(k,l) )
	468	f1_mg(k,l) = 2.0_wp * ( ddx2_mg(l) + ddy2_mg(l) ) + &
[1]	469	f2_mg(k,l) + f3_mg(k,l)
	470	ENDDO
	471	nzt_l = nzt_l / 2
[1353]	472	dx_l = dx_l * 2.0_wp
	473	dy_l = dy_l * 2.0_wp
[1]	474	ENDDO
	475
	476	ENDIF
	477
	478	!
	479	!-- Compute the reciprocal values of the horizontal grid lengths.
[1353]	480	ddx = 1.0_wp / dx
	481	ddy = 1.0_wp / dy
[1]	482	dx2 = dx * dx
	483	dy2 = dy * dy
[1353]	484	ddx2 = 1.0_wp / dx2
	485	ddy2 = 1.0_wp / dy2
[1]	486
	487	!
	488	!-- Compute the grid-dependent mixing length.
	489	DO k = 1, nzt
[1322]	490	l_grid(k) = ( dx * dy * dzw(k) )**0.33333333333333_wp
[1]	491	ENDDO
	492
	493	!
	494	!-- Allocate outer and inner index arrays for topography and set
[114]	495	!-- defaults.
[667]	496
[114]	497	ALLOCATE( corner_nl(nys:nyn,nxl:nxr), corner_nr(nys:nyn,nxl:nxr), &
	498	corner_sl(nys:nyn,nxl:nxr), corner_sr(nys:nyn,nxl:nxr), &
	499	wall_l(nys:nyn,nxl:nxr), wall_n(nys:nyn,nxl:nxr), &
[1968]	500	wall_r(nys:nyn,nxl:nxr), wall_s(nys:nyn,nxl:nxr) )
	501
[667]	502	ALLOCATE( fwxm(nysg:nyng,nxlg:nxrg), fwxp(nysg:nyng,nxlg:nxrg), &
	503	fwym(nysg:nyng,nxlg:nxrg), fwyp(nysg:nyng,nxlg:nxrg), &
	504	fxm(nysg:nyng,nxlg:nxrg), fxp(nysg:nyng,nxlg:nxrg), &
	505	fym(nysg:nyng,nxlg:nxrg), fyp(nysg:nyng,nxlg:nxrg), &
	506	nzb_s_inner(nysg:nyng,nxlg:nxrg), &
	507	nzb_s_outer(nysg:nyng,nxlg:nxrg), &
	508	nzb_u_inner(nysg:nyng,nxlg:nxrg), &
	509	nzb_u_outer(nysg:nyng,nxlg:nxrg), &
	510	nzb_v_inner(nysg:nyng,nxlg:nxrg), &
	511	nzb_v_outer(nysg:nyng,nxlg:nxrg), &
	512	nzb_w_inner(nysg:nyng,nxlg:nxrg), &
	513	nzb_w_outer(nysg:nyng,nxlg:nxrg), &
	514	nzb_diff_s_inner(nysg:nyng,nxlg:nxrg), &
	515	nzb_diff_s_outer(nysg:nyng,nxlg:nxrg), &
	516	nzb_diff_u(nysg:nyng,nxlg:nxrg), &
	517	nzb_diff_v(nysg:nyng,nxlg:nxrg), &
[1968]	518	nzb_local(nysg:nyng,nxlg:nxrg), &
	519	nzb_tmp(nysg:nyng,nxlg:nxrg), &
[1221]	520	rflags_s_inner(nzb:nzt+2,nysg:nyng,nxlg:nxrg), &
	521	rflags_invers(nysg:nyng,nxlg:nxrg,nzb:nzt+2), &
[667]	522	wall_e_x(nysg:nyng,nxlg:nxrg), &
	523	wall_e_y(nysg:nyng,nxlg:nxrg), &
	524	wall_u(nysg:nyng,nxlg:nxrg), &
	525	wall_v(nysg:nyng,nxlg:nxrg), &
	526	wall_w_x(nysg:nyng,nxlg:nxrg), &
	527	wall_w_y(nysg:nyng,nxlg:nxrg) )
[1]	528
	529
[667]	530
	531	ALLOCATE( l_wall(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
	532
[818]	533
[1]	534	nzb_s_inner = nzb; nzb_s_outer = nzb
	535	nzb_u_inner = nzb; nzb_u_outer = nzb
	536	nzb_v_inner = nzb; nzb_v_outer = nzb
	537	nzb_w_inner = nzb; nzb_w_outer = nzb
	538
[1353]	539	rflags_s_inner = 1.0_wp
	540	rflags_invers = 1.0_wp
[1221]	541
[1]	542	!
[19]	543	!-- Define vertical gridpoint from (or to) which on the usual finite difference
[1]	544	!-- form (which does not use surface fluxes) is applied
[1691]	545	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
[1]	546	nzb_diff = nzb + 2
	547	ELSE
	548	nzb_diff = nzb + 1
	549	ENDIF
[19]	550	IF ( use_top_fluxes ) THEN
	551	nzt_diff = nzt - 1
	552	ELSE
	553	nzt_diff = nzt
	554	ENDIF
[1]	555
	556	nzb_diff_s_inner = nzb_diff; nzb_diff_s_outer = nzb_diff
	557	nzb_diff_u = nzb_diff; nzb_diff_v = nzb_diff
	558
[1353]	559	wall_e_x = 0.0_wp; wall_e_y = 0.0_wp; wall_u = 0.0_wp; wall_v = 0.0_wp
	560	wall_w_x = 0.0_wp; wall_w_y = 0.0_wp
	561	fwxp = 1.0_wp; fwxm = 1.0_wp; fwyp = 1.0_wp; fwym = 1.0_wp
	562	fxp = 1.0_wp; fxm = 1.0_wp; fyp = 1.0_wp; fym = 1.0_wp
[1]	563
	564	!
	565	!-- Initialize near-wall mixing length l_wall only in the vertical direction
	566	!-- for the moment,
	567	!-- multiplication with wall_adjustment_factor near the end of this routine
	568	l_wall(nzb,:,:) = l_grid(1)
	569	DO k = nzb+1, nzt
	570	l_wall(k,:,:) = l_grid(k)
	571	ENDDO
	572	l_wall(nzt+1,:,:) = l_grid(nzt)
	573
	574	ALLOCATE ( vertical_influence(nzb:nzt) )
	575	DO k = 1, nzt
	576	vertical_influence(k) = MIN ( INT( l_grid(k) / &
[1353]	577	( wall_adjustment_factor * dzw(k) ) + 0.5_wp ), nzt - k )
[1]	578	ENDDO
	579
[1968]	580	DO k = 1, nzt
[1353]	581	IF ( l_grid(k) > 1.5_wp * dx * wall_adjustment_factor .OR. &
	582	l_grid(k) > 1.5_wp * dy * wall_adjustment_factor ) THEN
[254]	583	WRITE( message_string, * ) 'grid anisotropy exceeds ', &
	584	'threshold given by only local', &
	585	' &horizontal reduction of near_wall ', &
	586	'mixing length l_wall', &
	587	' &starting from height level k = ', k, '.'
	588	CALL message( 'init_grid', 'PA0202', 0, 1, 0, 6, 0 )
[1]	589	EXIT
	590	ENDIF
	591	ENDDO
	592	vertical_influence(0) = vertical_influence(1)
	593
[1968]	594	DO k = nzb + 1, nzb + vertical_influence(nzb)
	595	l_wall(k,:,:) = zu(k) - zw(nzb)
[1]	596	ENDDO
	597
	598	!
	599	!-- Set outer and inner index arrays for non-flat topography.
	600	!-- Here consistency checks concerning domain size and periodicity are
	601	!-- necessary.
	602	!-- Within this SELECT CASE structure only nzb_local is initialized
	603	!-- individually depending on the chosen topography type, all other index
	604	!-- arrays are initialized further below.
	605	SELECT CASE ( TRIM( topography ) )
	606
	607	CASE ( 'flat' )
	608	!
[555]	609	!-- nzb_local is required for the multigrid solver
	610	nzb_local = 0
[1]	611
	612	CASE ( 'single_building' )
	613	!
	614	!-- Single rectangular building, by default centered in the middle of the
	615	!-- total domain
	616	blx = NINT( building_length_x / dx )
	617	bly = NINT( building_length_y / dy )
[1675]	618	bh = MINLOC( ABS( zw - building_height ), 1 ) - 1
	619	IF ( ABS( zw(bh ) - building_height ) == &
	620	ABS( zw(bh+1) - building_height ) ) bh = bh + 1
[1]	621
[1322]	622	IF ( building_wall_left == 9999999.9_wp ) THEN
[1]	623	building_wall_left = ( nx + 1 - blx ) / 2 * dx
	624	ENDIF
	625	bxl = NINT( building_wall_left / dx )
	626	bxr = bxl + blx
	627
[1322]	628	IF ( building_wall_south == 9999999.9_wp ) THEN
[1]	629	building_wall_south = ( ny + 1 - bly ) / 2 * dy
	630	ENDIF
	631	bys = NINT( building_wall_south / dy )
	632	byn = bys + bly
	633
	634	!
	635	!-- Building size has to meet some requirements
	636	IF ( ( bxl < 1 ) .OR. ( bxr > nx-1 ) .OR. ( bxr < bxl+3 ) .OR. &
	637	( bys < 1 ) .OR. ( byn > ny-1 ) .OR. ( byn < bys+3 ) ) THEN
[274]	638	WRITE( message_string, * ) 'inconsistent building parameters:', &
	639	'& bxl=', bxl, 'bxr=', bxr, 'bys=', bys, &
	640	'byn=', byn, 'nx=', nx, 'ny=', ny
[254]	641	CALL message( 'init_grid', 'PA0203', 1, 2, 0, 6, 0 )
[1]	642	ENDIF
	643
	644	!
[1968]	645	!-- Define the building.
[1]	646	nzb_local = 0
[1968]	647	IF ( bxl <= nxr .AND. bxr >= nxl .AND. &
	648	bys <= nyn .AND. byn >= nys ) &
	649	nzb_local(MAX(nys,bys):MIN(nyn,byn),MAX(nxl,bxl):MIN(nxr,bxr)) = bh
[1]	650
[1994]	651	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
	652
[240]	653	CASE ( 'single_street_canyon' )
	654	!
	655	!-- Single quasi-2D street canyon of infinite length in x or y direction.
	656	!-- The canyon is centered in the other direction by default.
[1322]	657	IF ( canyon_width_x /= 9999999.9_wp ) THEN
[240]	658	!
	659	!-- Street canyon in y direction
	660	cwx = NINT( canyon_width_x / dx )
[1322]	661	IF ( canyon_wall_left == 9999999.9_wp ) THEN
[240]	662	canyon_wall_left = ( nx + 1 - cwx ) / 2 * dx
	663	ENDIF
	664	cxl = NINT( canyon_wall_left / dx )
	665	cxr = cxl + cwx
	666
[1322]	667	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
[240]	668	!
	669	!-- Street canyon in x direction
	670	cwy = NINT( canyon_width_y / dy )
[1322]	671	IF ( canyon_wall_south == 9999999.9_wp ) THEN
[240]	672	canyon_wall_south = ( ny + 1 - cwy ) / 2 * dy
	673	ENDIF
	674	cys = NINT( canyon_wall_south / dy )
	675	cyn = cys + cwy
	676
	677	ELSE
[254]	678
	679	message_string = 'no street canyon width given'
	680	CALL message( 'init_grid', 'PA0204', 1, 2, 0, 6, 0 )
	681
[240]	682	ENDIF
	683
[1675]	684	ch = MINLOC( ABS( zw - canyon_height ), 1 ) - 1
	685	IF ( ABS( zw(ch ) - canyon_height ) == &
	686	ABS( zw(ch+1) - canyon_height ) ) ch = ch + 1
	687
[240]	688	dp_level_ind_b = ch
	689	!
	690	!-- Street canyon size has to meet some requirements
[1322]	691	IF ( canyon_width_x /= 9999999.9_wp ) THEN
[1353]	692	IF ( ( cxl < 1 ) .OR. ( cxr > nx-1 ) .OR. ( cwx < 3 ) .OR. &
[240]	693	( ch < 3 ) ) THEN
[1353]	694	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
	695	'&cxl=', cxl, 'cxr=', cxr, &
	696	'cwx=', cwx, &
[254]	697	'ch=', ch, 'nx=', nx, 'ny=', ny
	698	CALL message( 'init_grid', 'PA0205', 1, 2, 0, 6, 0 )
[240]	699	ENDIF
[1322]	700	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
[1353]	701	IF ( ( cys < 1 ) .OR. ( cyn > ny-1 ) .OR. ( cwy < 3 ) .OR. &
[240]	702	( ch < 3 ) ) THEN
[1353]	703	WRITE( message_string, * ) 'inconsistent canyon parameters:', &
	704	'&cys=', cys, 'cyn=', cyn, &
	705	'cwy=', cwy, &
[254]	706	'ch=', ch, 'nx=', nx, 'ny=', ny
	707	CALL message( 'init_grid', 'PA0206', 1, 2, 0, 6, 0 )
[240]	708	ENDIF
	709	ENDIF
[1353]	710	IF ( canyon_width_x /= 9999999.9_wp .AND. &
	711	canyon_width_y /= 9999999.9_wp ) THEN
	712	message_string = 'inconsistent canyon parameters:' // &
	713	'&street canyon can only be oriented' // &
[254]	714	'&either in x- or in y-direction'
	715	CALL message( 'init_grid', 'PA0207', 1, 2, 0, 6, 0 )
[240]	716	ENDIF
	717
	718	nzb_local = ch
[1322]	719	IF ( canyon_width_x /= 9999999.9_wp ) THEN
[1968]	720	IF ( cxl <= nxr .AND. cxr >= nxl ) &
	721	nzb_local(:,MAX(nxl,cxl+1):MIN(nxr,cxr-1)) = 0
[1322]	722	ELSEIF ( canyon_width_y /= 9999999.9_wp ) THEN
[1968]	723	IF ( cys <= nyn .AND. cyn >= nys ) &
	724	nzb_local(MAX(nys,cys+1):MIN(nyn,cyn-1),:) = 0
[240]	725	ENDIF
	726
[1994]	727	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
	728
[1]	729	CASE ( 'read_from_file' )
[759]	730
[1968]	731	ALLOCATE ( topo_height(nys:nyn,nxl:nxr) )
[818]	732
[759]	733	DO ii = 0, io_blocks-1
	734	IF ( ii == io_group ) THEN
	735
[1]	736	!
[759]	737	!-- Arbitrary irregular topography data in PALM format (exactly
	738	!-- matching the grid size and total domain size)
[1779]	739	OPEN( 90, FILE='TOPOGRAPHY_DATA'//TRIM( coupling_char ), &
	740	STATUS='OLD', FORM='FORMATTED', ERR=10 )
[1968]	741	!
	742	!-- Read topography PE-wise. Rows are read from nyn to nys, columns
	743	!-- are read from nxl to nxr. At first, ny-nyn rows need to be skipped.
	744	skip_n_rows = 0
	745	DO WHILE ( skip_n_rows < ny - nyn )
	746	READ( 90, * )
	747	skip_n_rows = skip_n_rows + 1
[759]	748	ENDDO
[1968]	749	!
	750	!-- Read data from nyn to nys and nxl to nxr. Therefore, skip
	751	!-- column until nxl-1 is reached
	752	DO j = nyn, nys, -1
	753	READ( 90, *, ERR=11, END=11 ) &
	754	( dum, i = 0, nxl-1 ), &
	755	( topo_height(j,i), i = nxl, nxr )
	756	ENDDO
[759]	757
	758	GOTO 12
	759
[1779]	760	10 message_string = 'file TOPOGRAPHY'//TRIM( coupling_char )// &
	761	' does not exist'
[759]	762	CALL message( 'init_grid', 'PA0208', 1, 2, 0, 6, 0 )
	763
[1779]	764	11 message_string = 'errors in file TOPOGRAPHY_DATA'// &
	765	TRIM( coupling_char )
[759]	766	CALL message( 'init_grid', 'PA0209', 1, 2, 0, 6, 0 )
	767
	768	12 CLOSE( 90 )
	769
	770	ENDIF
[1804]	771	#if defined( __parallel )
[759]	772	CALL MPI_BARRIER( comm2d, ierr )
	773	#endif
[559]	774	ENDDO
[759]	775
[1]	776	!
	777	!-- Calculate the index height of the topography
[1968]	778	nzb_local = 0
	779	DO i = nxl, nxr
	780	DO j = nys, nyn
[1675]	781	nzb_local(j,i) = MINLOC( ABS( zw - topo_height(j,i) ), 1 ) - 1
	782	IF ( ABS( zw(nzb_local(j,i) ) - topo_height(j,i) ) == &
	783	ABS( zw(nzb_local(j,i)+1) - topo_height(j,i) ) ) &
	784	nzb_local(j,i) = nzb_local(j,i) + 1
[1]	785	ENDDO
	786	ENDDO
[818]	787
	788	DEALLOCATE ( topo_height )
[1942]	789	!
	790	!-- Filter topography, i.e. fill holes resolved by only one grid point.
	791	!-- Such holes are suspected to lead to velocity blow-ups as continuity
	792	!-- equation on discrete grid cannot be fulfilled in such case.
	793	!-- For now, check only for holes and fill them to the lowest height level
	794	!-- of the directly adjoining grid points along x- and y- direction.
	795	!-- Before checking for holes, set lateral boundary conditions for
	796	!-- topography. After hole-filling, boundary conditions must be set again!
[1968]	797	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
	798
	799	IF ( .NOT. bc_ns_cyc ) THEN
	800	IF ( nys == 0 ) nzb_local(-1,:) = nzb_local(0,:)
	801	IF ( nyn == ny ) nzb_local(ny+1,:) = nzb_local(ny,:)
[1942]	802	ENDIF
[1910]	803
[1968]	804	IF ( .NOT. bc_lr_cyc ) THEN
	805	IF ( nxl == 0 ) nzb_local(:,-1) = nzb_local(:,0)
	806	IF ( nxr == nx ) nzb_local(:,nx+1) = nzb_local(:,nx)
[1942]	807	ENDIF
	808
[1968]	809	num_hole_l = 0
	810	DO i = nxl, nxr
	811	DO j = nys, nyn
[1942]	812
	813	num_wall = 0
	814
	815	IF ( nzb_local(j-1,i) > nzb_local(j,i) ) &
	816	num_wall = num_wall + 1
	817	IF ( nzb_local(j+1,i) > nzb_local(j,i) ) &
	818	num_wall = num_wall + 1
	819	IF ( nzb_local(j,i-1) > nzb_local(j,i) ) &
	820	num_wall = num_wall + 1
	821	IF ( nzb_local(j,i+1) > nzb_local(j,i) ) &
	822	num_wall = num_wall + 1
	823
	824	IF ( num_wall == 4 ) THEN
	825	nzb_local(j,i) = MIN( nzb_local(j-1,i), nzb_local(j+1,i), &
	826	nzb_local(j,i-1), nzb_local(j,i+1) )
[1968]	827	num_hole_l = num_hole_l + 1
[1942]	828	ENDIF
	829	ENDDO
	830	ENDDO
[114]	831	!
[1968]	832	!-- Count the total number of holes, required for informative message.
	833	#if defined( __parallel )
	834	CALL MPI_ALLREDUCE( num_hole_l, num_hole, 1, MPI_INTEGER, MPI_SUM, &
	835	comm2d, ierr )
	836	#else
	837	num_hole = num_hole_l
	838	#endif
	839	!
[1942]	840	!-- Create an informative message if any hole was removed.
[1968]	841	IF ( num_hole > 0 ) THEN
[1942]	842	WRITE( message_string, * ) num_hole, 'hole(s) resolved by only '//&
	843	'one grid point were filled'
	844	CALL message( 'init_grid', 'PA0430', 0, 0, 0, 6, 0 )
	845	ENDIF
	846	!
[1968]	847	!-- Exchange ghost-points, as well as add cyclic or Neumann boundary
	848	!-- conditions.
	849	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
	850
	851	IF ( .NOT. bc_ns_cyc ) THEN
	852	IF ( nys == 0 ) nzb_local(-1,:) = nzb_local(0,:)
	853	IF ( nyn == ny ) nzb_local(ny+1,:) = nzb_local(ny,:)
[1910]	854	ENDIF
[667]	855
[1968]	856	IF ( .NOT. bc_lr_cyc ) THEN
	857	IF ( nxl == 0 ) nzb_local(:,-1) = nzb_local(:,0)
	858	IF ( nxr == nx ) nzb_local(:,nx+1) = nzb_local(:,nx)
[1910]	859	ENDIF
	860
[1]	861	CASE DEFAULT
	862	!
	863	!-- The DEFAULT case is reached either if the parameter topography
[217]	864	!-- contains a wrong character string or if the user has defined a special
[1]	865	!-- case in the user interface. There, the subroutine user_init_grid
	866	!-- checks which of these two conditions applies.
[1968]	867	CALL user_init_grid( nzb_local )
[1]	868
	869	END SELECT
	870	!
[861]	871	!-- Determine the maximum level of topography. Furthermore it is used for
	872	!-- steering the degradation of order of the applied advection scheme.
[978]	873	!-- In case of non-cyclic lateral boundaries, the order of the advection
[1968]	874	!-- scheme has to be reduced up to nzt (required at the lateral boundaries).
	875	#if defined( __parallel )
	876	CALL MPI_ALLREDUCE( MAXVAL( nzb_local ) + 1, nzb_max, 1, MPI_INTEGER, &
	877	MPI_MAX, comm2d, ierr )
	878	#else
[1677]	879	nzb_max = MAXVAL( nzb_local ) + 1
[1968]	880	#endif
[1353]	881	IF ( inflow_l .OR. outflow_l .OR. inflow_r .OR. outflow_r .OR. &
[1762]	882	inflow_n .OR. outflow_n .OR. inflow_s .OR. outflow_s .OR. &
	883	nest_domain ) &
	884	THEN
	885	nzb_max = nzt
[978]	886	ENDIF
	887
[861]	888	!
[1]	889	!-- Consistency checks and index array initialization are only required for
[217]	890	!-- non-flat topography, also the initialization of topography height arrays
[49]	891	!-- zu_s_inner and zw_w_inner
[1]	892	IF ( TRIM( topography ) /= 'flat' ) THEN
[1968]	893	#if defined( __parallel )
	894	CALL MPI_ALLREDUCE( MAXVAL( nzb_local ), nzb_local_max, 1, MPI_INTEGER, &
	895	MPI_MAX, comm2d, ierr )
[1982]	896	CALL MPI_ALLREDUCE( MINVAL( nzb_local ), nzb_local_min, 1, MPI_INTEGER, &
[1968]	897	MPI_MIN, comm2d, ierr )
	898	#else
	899	nzb_local_max = MAXVAL( nzb_local )
	900	nzb_local_min = MINVAL( nzb_local )
	901	#endif
[1982]	902
[1]	903	!
	904	!-- Consistency checks
[1968]	905	IF ( nzb_local_min < 0 .OR. nzb_local_max > nz + 1 ) THEN
[1353]	906	WRITE( message_string, * ) 'nzb_local values are outside the', &
	907	'model domain', &
[1968]	908	'&MINVAL( nzb_local ) = ', nzb_local_min, &
	909	'&MAXVAL( nzb_local ) = ', nzb_local_max
[254]	910	CALL message( 'init_grid', 'PA0210', 1, 2, 0, 6, 0 )
[1]	911	ENDIF
	912
[217]	913	IF ( topography_grid_convention == 'cell_edge' ) THEN
[134]	914	!
[217]	915	!-- The array nzb_local as defined using the 'cell_edge' convention
	916	!-- describes the actual total size of topography which is defined at the
	917	!-- cell edges where u=0 on the topography walls in x-direction and v=0
	918	!-- on the topography walls in y-direction. However, PALM uses individual
	919	!-- arrays nzb_u\|v\|w\|s_inner\|outer that are based on nzb_s_inner.
	920	!-- Therefore, the extent of topography in nzb_local is now reduced by
	921	!-- 1dx at the E topography walls and by 1dy at the N topography walls
[1968]	922	!-- to form the basis for nzb_s_inner.
	923	!-- Note, the reverse memory access (i-j instead of j-i) is absolutely
	924	!-- required at this point.
	925	DO j = nys+1, nyn+1
	926	DO i = nxl-1, nxr
[217]	927	nzb_local(j,i) = MIN( nzb_local(j,i), nzb_local(j,i+1) )
	928	ENDDO
[134]	929	ENDDO
[1968]	930	!
	931	!-- Exchange ghost points
	932	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
	933
	934	DO i = nxl, nxr+1
	935	DO j = nys-1, nyn
[217]	936	nzb_local(j,i) = MIN( nzb_local(j,i), nzb_local(j+1,i) )
	937	ENDDO
[134]	938	ENDDO
[1968]	939	!
	940	!-- Exchange ghost points
	941	CALL exchange_horiz_2d_int( nzb_local, nys, nyn, nxl, nxr, nbgp )
[217]	942	ENDIF
[1]	943	!
	944	!-- Initialize index arrays nzb_s_inner and nzb_w_inner
[1968]	945	nzb_s_inner = nzb_local
	946	nzb_w_inner = nzb_local
[1]	947
	948	!
	949	!-- Initialize remaining index arrays:
	950	!-- first pre-initialize them with nzb_s_inner...
	951	nzb_u_inner = nzb_s_inner
	952	nzb_u_outer = nzb_s_inner
	953	nzb_v_inner = nzb_s_inner
	954	nzb_v_outer = nzb_s_inner
	955	nzb_w_outer = nzb_s_inner
	956	nzb_s_outer = nzb_s_inner
	957
	958	!
	959	!-- ...then extend pre-initialized arrays in their according directions
	960	!-- based on nzb_local using nzb_tmp as a temporary global index array
	961
	962	!
	963	!-- nzb_s_outer:
	964	!-- extend nzb_local east-/westwards first, then north-/southwards
[1968]	965	nzb_tmp = nzb_local
	966	DO j = nys, nyn
	967	DO i = nxl, nxr
[1353]	968	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i), &
[1]	969	nzb_local(j,i+1) )
	970	ENDDO
	971	ENDDO
[1968]	972
	973	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
	974
[1]	975	DO i = nxl, nxr
	976	DO j = nys, nyn
[1353]	977	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
[1]	978	nzb_tmp(j+1,i) )
	979	ENDDO
	980	!
	981	!-- non-cyclic boundary conditions (overwritten by call of
	982	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
	983	IF ( nys == 0 ) THEN
	984	j = -1
	985	nzb_s_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
	986	ENDIF
[1743]	987	IF ( nyn == ny ) THEN
[1]	988	j = ny + 1
	989	nzb_s_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
	990	ENDIF
	991	ENDDO
	992	!
	993	!-- nzb_w_outer:
	994	!-- identical to nzb_s_outer
	995	nzb_w_outer = nzb_s_outer
	996
	997	!
	998	!-- nzb_u_inner:
	999	!-- extend nzb_local rightwards only
[1968]	1000	nzb_tmp = nzb_local
	1001	DO j = nys, nyn
	1002	DO i = nxl, nxr
[1]	1003	nzb_tmp(j,i) = MAX( nzb_local(j,i-1), nzb_local(j,i) )
	1004	ENDDO
	1005	ENDDO
[1968]	1006
	1007	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
	1008
	1009	nzb_u_inner = nzb_tmp
[1]	1010	!
	1011	!-- nzb_u_outer:
	1012	!-- extend current nzb_tmp (nzb_u_inner) north-/southwards
	1013	DO i = nxl, nxr
	1014	DO j = nys, nyn
[1353]	1015	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i), &
[1]	1016	nzb_tmp(j+1,i) )
	1017	ENDDO
	1018	!
	1019	!-- non-cyclic boundary conditions (overwritten by call of
	1020	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
	1021	IF ( nys == 0 ) THEN
	1022	j = -1
	1023	nzb_u_outer(j,i) = MAX( nzb_tmp(j+1,i), nzb_tmp(j,i) )
	1024	ENDIF
[1743]	1025	IF ( nyn == ny ) THEN
[1]	1026	j = ny + 1
	1027	nzb_u_outer(j,i) = MAX( nzb_tmp(j-1,i), nzb_tmp(j,i) )
	1028	ENDIF
	1029	ENDDO
	1030
	1031	!
	1032	!-- nzb_v_inner:
	1033	!-- extend nzb_local northwards only
[1968]	1034	nzb_tmp = nzb_local
	1035	DO i = nxl, nxr
	1036	DO j = nys, nyn
[1]	1037	nzb_tmp(j,i) = MAX( nzb_local(j-1,i), nzb_local(j,i) )
	1038	ENDDO
	1039	ENDDO
[1968]	1040
	1041	CALL exchange_horiz_2d_int( nzb_tmp, nys, nyn, nxl, nxr, nbgp )
	1042	nzb_v_inner = nzb_tmp
[1]	1043
	1044	!
	1045	!-- nzb_v_outer:
	1046	!-- extend current nzb_tmp (nzb_v_inner) right-/leftwards
	1047	DO j = nys, nyn
	1048	DO i = nxl, nxr
[1353]	1049	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i), &
[1]	1050	nzb_tmp(j,i+1) )
	1051	ENDDO
	1052	!
	1053	!-- non-cyclic boundary conditions (overwritten by call of
	1054	!-- exchange_horiz_2d_int below in case of cyclic boundary conditions)
	1055	IF ( nxl == 0 ) THEN
	1056	i = -1
	1057	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i+1), nzb_tmp(j,i) )
	1058	ENDIF
	1059	IF ( nxr == nx ) THEN
	1060	i = nx + 1
	1061	nzb_v_outer(j,i) = MAX( nzb_tmp(j,i-1), nzb_tmp(j,i) )
	1062	ENDIF
	1063	ENDDO
[1804]	1064
[1]	1065	!
	1066	!-- Exchange of lateral boundary values (parallel computers) and cyclic
	1067	!-- boundary conditions, if applicable.
	1068	!-- Since nzb_s_inner and nzb_w_inner are derived directly from nzb_local
	1069	!-- they do not require exchange and are not included here.
[1968]	1070	CALL exchange_horiz_2d_int( nzb_u_inner, nys, nyn, nxl, nxr, nbgp )
	1071	CALL exchange_horiz_2d_int( nzb_u_outer, nys, nyn, nxl, nxr, nbgp )
	1072	CALL exchange_horiz_2d_int( nzb_v_inner, nys, nyn, nxl, nxr, nbgp )
	1073	CALL exchange_horiz_2d_int( nzb_v_outer, nys, nyn, nxl, nxr, nbgp )
	1074	CALL exchange_horiz_2d_int( nzb_w_outer, nys, nyn, nxl, nxr, nbgp )
	1075	CALL exchange_horiz_2d_int( nzb_s_outer, nys, nyn, nxl, nxr, nbgp )
[1]	1076
[49]	1077	!
	1078	!-- Allocate and set the arrays containing the topography height
[1968]	1079	ALLOCATE( zu_s_inner(0:nx+1,0:ny+1), zw_w_inner(0:nx+1,0:ny+1), &
	1080	zu_s_inner_l(0:nx+1,0:ny+1), zw_w_inner_l(0:nx+1,0:ny+1) )
	1081
	1082	zu_s_inner = 0.0_wp
	1083	zw_w_inner = 0.0_wp
	1084	zu_s_inner_l = 0.0_wp
	1085	zw_w_inner_l = 0.0_wp
	1086
	1087	DO i = nxl, nxr
	1088	DO j = nys, nyn
	1089	zu_s_inner_l(i,j) = zu(nzb_local(j,i))
	1090	zw_w_inner_l(i,j) = zw(nzb_local(j,i))
	1091	ENDDO
	1092	ENDDO
	1093
	1094	#if defined( __parallel )
	1095	CALL MPI_REDUCE( zu_s_inner_l, zu_s_inner, (nx+2)*(ny+2), &
	1096	MPI_REAL, MPI_SUM, 0, comm2d, ierr )
	1097	CALL MPI_REDUCE( zw_w_inner_l, zw_w_inner, (nx+2)*(ny+2), &
	1098	MPI_REAL, MPI_SUM, 0, comm2d, ierr )
	1099	#else
	1100	zu_s_inner = zu_s_inner_l
	1101	zw_w_inner = zw_w_inner_l
	1102	#endif
[49]	1103
[1968]	1104	DEALLOCATE( zu_s_inner_l, zw_w_inner_l )
	1105	IF ( myid /= 0 ) DEALLOCATE( zu_s_inner, zw_w_inner )
[1221]	1106	!
[1968]	1107	!-- Set south and left ghost points, required for netcdf output
	1108	IF ( myid == 0 ) THEN
	1109	IF( bc_lr_cyc ) THEN
	1110	zu_s_inner(nx+1,:) = zu_s_inner(0,:)
	1111	zw_w_inner(nx+1,:) = zw_w_inner(0,:)
	1112	ELSE
	1113	zu_s_inner(nx+1,:) = zu_s_inner(nx,:)
	1114	zw_w_inner(nx+1,:) = zw_w_inner(nx,:)
	1115	ENDIF
	1116	IF( bc_ns_cyc ) THEN
	1117	zu_s_inner(:,ny+1) = zu_s_inner(:,0)
	1118	zw_w_inner(:,ny+1) = zw_w_inner(:,0)
	1119	ELSE
	1120	zu_s_inner(:,ny+1) = zu_s_inner(:,ny)
	1121	zw_w_inner(:,ny+1) = zw_w_inner(:,ny)
	1122	ENDIF
	1123	ENDIF
	1124	!
[1221]	1125	!-- Set flag arrays to be used for masking of grid points
	1126	DO i = nxlg, nxrg
	1127	DO j = nysg, nyng
	1128	DO k = nzb, nzt+1
[1353]	1129	IF ( k <= nzb_s_inner(j,i) ) rflags_s_inner(k,j,i) = 0.0_wp
	1130	IF ( k <= nzb_s_inner(j,i) ) rflags_invers(j,i,k) = 0.0_wp
[1221]	1131	ENDDO
	1132	ENDDO
	1133	ENDDO
[1804]	1134
[1]	1135	ENDIF
[1968]	1136	!
	1137	!-- Deallocate temporary array, as it might be reused for different
	1138	!-- grid-levels further below.
	1139	DEALLOCATE( nzb_tmp )
[1]	1140
	1141	!
	1142	!-- Set the individual index arrays which define the k index from which on
	1143	!-- the usual finite difference form (which does not use surface fluxes) is
	1144	!-- applied
[1691]	1145	IF ( constant_flux_layer .OR. use_surface_fluxes ) THEN
[1]	1146	nzb_diff_u = nzb_u_inner + 2
	1147	nzb_diff_v = nzb_v_inner + 2
	1148	nzb_diff_s_inner = nzb_s_inner + 2
	1149	nzb_diff_s_outer = nzb_s_outer + 2
	1150	ELSE
	1151	nzb_diff_u = nzb_u_inner + 1
	1152	nzb_diff_v = nzb_v_inner + 1
	1153	nzb_diff_s_inner = nzb_s_inner + 1
	1154	nzb_diff_s_outer = nzb_s_outer + 1
	1155	ENDIF
	1156
	1157	!
	1158	!-- Calculation of wall switches and factors required by diffusion_u/v.f90 and
	1159	!-- for limitation of near-wall mixing length l_wall further below
	1160	corner_nl = 0
	1161	corner_nr = 0
	1162	corner_sl = 0
	1163	corner_sr = 0
	1164	wall_l = 0
	1165	wall_n = 0
	1166	wall_r = 0
	1167	wall_s = 0
	1168
	1169	DO i = nxl, nxr
	1170	DO j = nys, nyn
	1171	!
	1172	!-- u-component
	1173	IF ( nzb_u_outer(j,i) > nzb_u_outer(j+1,i) ) THEN
[1353]	1174	wall_u(j,i) = 1.0_wp ! north wall (location of adjacent fluid)
	1175	fym(j,i) = 0.0_wp
	1176	fyp(j,i) = 1.0_wp
[1]	1177	ELSEIF ( nzb_u_outer(j,i) > nzb_u_outer(j-1,i) ) THEN
[1353]	1178	wall_u(j,i) = 1.0_wp ! south wall (location of adjacent fluid)
	1179	fym(j,i) = 1.0_wp
	1180	fyp(j,i) = 0.0_wp
[1]	1181	ENDIF
	1182	!
	1183	!-- v-component
	1184	IF ( nzb_v_outer(j,i) > nzb_v_outer(j,i+1) ) THEN
[1353]	1185	wall_v(j,i) = 1.0_wp ! rigth wall (location of adjacent fluid)
	1186	fxm(j,i) = 0.0_wp
	1187	fxp(j,i) = 1.0_wp
[1]	1188	ELSEIF ( nzb_v_outer(j,i) > nzb_v_outer(j,i-1) ) THEN
[1353]	1189	wall_v(j,i) = 1.0_wp ! left wall (location of adjacent fluid)
	1190	fxm(j,i) = 1.0_wp
	1191	fxp(j,i) = 0.0_wp
[1]	1192	ENDIF
	1193	!
	1194	!-- w-component, also used for scalars, separate arrays for shear
	1195	!-- production of tke
	1196	IF ( nzb_w_outer(j,i) > nzb_w_outer(j+1,i) ) THEN
[1353]	1197	wall_e_y(j,i) = 1.0_wp ! north wall (location of adjacent fluid)
	1198	wall_w_y(j,i) = 1.0_wp
	1199	fwym(j,i) = 0.0_wp
	1200	fwyp(j,i) = 1.0_wp
[1]	1201	ELSEIF ( nzb_w_outer(j,i) > nzb_w_outer(j-1,i) ) THEN
[1353]	1202	wall_e_y(j,i) = -1.0_wp ! south wall (location of adjacent fluid)
	1203	wall_w_y(j,i) = 1.0_wp
	1204	fwym(j,i) = 1.0_wp
	1205	fwyp(j,i) = 0.0_wp
[1]	1206	ENDIF
	1207	IF ( nzb_w_outer(j,i) > nzb_w_outer(j,i+1) ) THEN
[1353]	1208	wall_e_x(j,i) = 1.0_wp ! right wall (location of adjacent fluid)
	1209	wall_w_x(j,i) = 1.0_wp
	1210	fwxm(j,i) = 0.0_wp
	1211	fwxp(j,i) = 1.0_wp
[1]	1212	ELSEIF ( nzb_w_outer(j,i) > nzb_w_outer(j,i-1) ) THEN
[1353]	1213	wall_e_x(j,i) = -1.0_wp ! left wall (location of adjacent fluid)
	1214	wall_w_x(j,i) = 1.0_wp
	1215	fwxm(j,i) = 1.0_wp
	1216	fwxp(j,i) = 0.0_wp
[1]	1217	ENDIF
	1218	!
	1219	!-- Wall and corner locations inside buildings for limitation of
	1220	!-- near-wall mixing length l_wall
	1221	IF ( nzb_s_inner(j,i) > nzb_s_inner(j+1,i) ) THEN
	1222
	1223	wall_n(j,i) = nzb_s_inner(j+1,i) + 1 ! North wall
	1224
	1225	IF ( nzb_s_inner(j,i) > nzb_s_inner(j,i-1) ) THEN
	1226	corner_nl(j,i) = MAX( nzb_s_inner(j+1,i), & ! Northleft corner
	1227	nzb_s_inner(j,i-1) ) + 1
	1228	ENDIF
	1229
	1230	IF ( nzb_s_inner(j,i) > nzb_s_inner(j,i+1) ) THEN
	1231	corner_nr(j,i) = MAX( nzb_s_inner(j+1,i), & ! Northright corner
	1232	nzb_s_inner(j,i+1) ) + 1
	1233	ENDIF
	1234
	1235	ENDIF
	1236
	1237	IF ( nzb_s_inner(j,i) > nzb_s_inner(j-1,i) ) THEN
	1238
	1239	wall_s(j,i) = nzb_s_inner(j-1,i) + 1 ! South wall
	1240	IF ( nzb_s_inner(j,i) > nzb_s_inner(j,i-1) ) THEN
	1241	corner_sl(j,i) = MAX( nzb_s_inner(j-1,i), & ! Southleft corner
	1242	nzb_s_inner(j,i-1) ) + 1
	1243	ENDIF
	1244
	1245	IF ( nzb_s_inner(j,i) > nzb_s_inner(j,i+1) ) THEN
	1246	corner_sr(j,i) = MAX( nzb_s_inner(j-1,i), & ! Southright corner
	1247	nzb_s_inner(j,i+1) ) + 1
	1248	ENDIF
	1249
	1250	ENDIF
	1251
	1252	IF ( nzb_s_inner(j,i) > nzb_s_inner(j,i-1) ) THEN
	1253	wall_l(j,i) = nzb_s_inner(j,i-1) + 1 ! Left wall
	1254	ENDIF
	1255
	1256	IF ( nzb_s_inner(j,i) > nzb_s_inner(j,i+1) ) THEN
	1257	wall_r(j,i) = nzb_s_inner(j,i+1) + 1 ! Right wall
	1258	ENDIF
	1259
	1260	ENDDO
	1261	ENDDO
	1262	!
[1931]	1263	!-- Calculate wall flag arrays for the multigrid method.
	1264	!-- Please note, wall flags are only applied in the not cache-optimized
	1265	!-- version.
	1266	IF ( psolver == 'multigrid_noopt' ) THEN
[1968]	1267
[114]	1268	!
[1968]	1269	!-- Gridpoint increment of the current level.
[114]	1270	inc = 1
	1271	DO l = maximum_grid_level, 1 , -1
[1968]	1272	!
	1273	!-- Set grid_level as it is required for exchange_horiz_2d_int
	1274	grid_level = l
[114]	1275
	1276	nxl_l = nxl_mg(l)
	1277	nxr_l = nxr_mg(l)
	1278	nys_l = nys_mg(l)
	1279	nyn_l = nyn_mg(l)
	1280	nzt_l = nzt_mg(l)
	1281	!
	1282	!-- Assign the flag level to be calculated
	1283	SELECT CASE ( l )
	1284	CASE ( 1 )
	1285	flags => wall_flags_1
	1286	CASE ( 2 )
	1287	flags => wall_flags_2
	1288	CASE ( 3 )
	1289	flags => wall_flags_3
	1290	CASE ( 4 )
	1291	flags => wall_flags_4
	1292	CASE ( 5 )
	1293	flags => wall_flags_5
	1294	CASE ( 6 )
	1295	flags => wall_flags_6
	1296	CASE ( 7 )
	1297	flags => wall_flags_7
	1298	CASE ( 8 )
	1299	flags => wall_flags_8
	1300	CASE ( 9 )
	1301	flags => wall_flags_9
	1302	CASE ( 10 )
	1303	flags => wall_flags_10
	1304	END SELECT
	1305
	1306	!
	1307	!-- Depending on the grid level, set the respective bits in case of
	1308	!-- neighbouring walls
	1309	!-- Bit 0: wall to the bottom
	1310	!-- Bit 1: wall to the top (not realized in remaining PALM code so far)
	1311	!-- Bit 2: wall to the south
	1312	!-- Bit 3: wall to the north
	1313	!-- Bit 4: wall to the left
	1314	!-- Bit 5: wall to the right
[116]	1315	!-- Bit 6: inside building
[114]	1316
	1317	flags = 0
	1318
[927]	1319	!
	1320	!-- In case of masking method, flags are not set and multigrid method
	1321	!-- works like FFT-solver
[1931]	1322	IF ( .NOT. masking_method ) THEN
[927]	1323
[1968]	1324	!
	1325	!-- Allocate temporary array for topography heights on coarser grid
	1326	!-- level. Please note, 2 ghoist points are required, in order to
	1327	!-- calculate flags() on the interior ghost point.
	1328	ALLOCATE( nzb_tmp(nys_l-2:nyn_l+2,nxl_l-2:nxr_l+2) )
	1329	nzb_tmp = 0
	1330
	1331	DO i = nxl_l, nxr_l
	1332	DO j = nys_l, nyn_l
	1333	nzb_tmp(j,i) = nzb_local(jinc,iinc)
	1334	ENDDO
	1335	ENDDO
	1336	!
	1337	!-- Exchange ghost points on respective multigrid level. 2 ghost points
	1338	!-- are required, in order to calculate flags on
	1339	!-- nys_l-1 / nyn_l+1 / nxl_l-1 / nxr_l+1. The alternative would be to
	1340	!-- exchange 3D-INTEGER array flags on the respective multigrid level.
	1341	CALL exchange_horiz_2d_int( nzb_tmp, nys_l, nyn_l, nxl_l, nxr_l, 2 )
	1342	!
	1343	!-- Set non-cyclic boundary conditions on respective multigrid level
	1344	IF ( .NOT. bc_ns_cyc ) THEN
	1345	IF ( nys == 0 ) THEN
	1346	nzb_tmp(-2,:) = nzb_tmp(0,:)
	1347	nzb_tmp(-1,:) = nzb_tmp(0,:)
	1348	ENDIF
	1349	IF ( nyn == ny ) THEN
	1350	nzb_tmp(ny+2,:) = nzb_tmp(ny,:)
	1351	nzb_tmp(ny+1,:) = nzb_tmp(ny,:)
	1352	ENDIF
	1353	ENDIF
	1354	IF ( .NOT. bc_lr_cyc ) THEN
	1355	IF ( nxl == 0 ) THEN
	1356	nzb_tmp(:,-2) = nzb_tmp(:,0)
	1357	nzb_tmp(:,-1) = nzb_tmp(:,0)
	1358	ENDIF
	1359	IF ( nxr == nx ) THEN
	1360	nzb_tmp(:,nx+1) = nzb_tmp(:,nx)
	1361	nzb_tmp(:,nx+2) = nzb_tmp(:,nx)
	1362	ENDIF
	1363	ENDIF
	1364
[927]	1365	DO i = nxl_l-1, nxr_l+1
	1366	DO j = nys_l-1, nyn_l+1
[1968]	1367	DO k = nzb, nzt_l+1
[114]	1368	!
[927]	1369	!-- Inside/outside building (inside building does not need
	1370	!-- further tests for walls)
[1968]	1371	IF ( k*inc <= nzb_tmp(j,i) ) THEN
[114]	1372
[927]	1373	flags(k,j,i) = IBSET( flags(k,j,i), 6 )
[114]	1374
[927]	1375	ELSE
[114]	1376	!
[927]	1377	!-- Bottom wall
[1968]	1378	IF ( (k-1)*inc <= nzb_tmp(j,i) ) THEN
[927]	1379	flags(k,j,i) = IBSET( flags(k,j,i), 0 )
	1380	ENDIF
[114]	1381	!
[927]	1382	!-- South wall
[1968]	1383	IF ( k*inc <= nzb_tmp(j-1,i) ) THEN
[927]	1384	flags(k,j,i) = IBSET( flags(k,j,i), 2 )
	1385	ENDIF
[114]	1386	!
[927]	1387	!-- North wall
[1968]	1388	IF ( k*inc <= nzb_tmp(j+1,i) ) THEN
[927]	1389	flags(k,j,i) = IBSET( flags(k,j,i), 3 )
	1390	ENDIF
[114]	1391	!
[927]	1392	!-- Left wall
[1968]	1393	IF ( k*inc <= nzb_tmp(j,i-1) ) THEN
[927]	1394	flags(k,j,i) = IBSET( flags(k,j,i), 4 )
	1395	ENDIF
[114]	1396	!
[927]	1397	!-- Right wall
[1968]	1398	IF ( k*inc <= nzb_tmp(j,i+1) ) THEN
[927]	1399	flags(k,j,i) = IBSET( flags(k,j,i), 5 )
	1400	ENDIF
	1401
[114]	1402	ENDIF
	1403
[927]	1404	ENDDO
[114]	1405	ENDDO
	1406	ENDDO
	1407
[1968]	1408	DEALLOCATE( nzb_tmp )
	1409
[927]	1410	ENDIF
	1411
[114]	1412	inc = inc * 2
	1413
	1414	ENDDO
[1968]	1415	!
	1416	!-- Reset grid_level to "normal" grid
	1417	grid_level = 0
	1418
[114]	1419	ENDIF
[861]	1420	!
[1942]	1421	!-- Allocate flags needed for masking walls. Even though these flags are only
	1422	!-- required in the ws-scheme, the arrays need to be allocated as they are
	1423	!-- used in OpenACC directives.
[1677]	1424	ALLOCATE( wall_flags_0(nzb:nzt+1,nysg:nyng,nxlg:nxrg), &
	1425	wall_flags_00(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
[1221]	1426	wall_flags_0 = 0
	1427	wall_flags_00 = 0
[114]	1428	!
[1942]	1429	!-- Init flags for ws-scheme to degrade order near walls
	1430	IF ( momentum_advec == 'ws-scheme' .OR. scalar_advec == 'ws-scheme' .OR.&
	1431	scalar_advec == 'ws-scheme-mono' ) THEN
	1432	CALL ws_init_flags
[861]	1433	ENDIF
	1434
	1435	!
[1]	1436	!-- In case of topography: limit near-wall mixing length l_wall further:
	1437	!-- Go through all points of the subdomain one by one and look for the closest
	1438	!-- surface
	1439	IF ( TRIM(topography) /= 'flat' ) THEN
	1440	DO i = nxl, nxr
	1441	DO j = nys, nyn
	1442
	1443	nzb_si = nzb_s_inner(j,i)
	1444	vi = vertical_influence(nzb_si)
	1445
	1446	IF ( wall_n(j,i) > 0 ) THEN
	1447	!
	1448	!-- North wall (y distance)
	1449	DO k = wall_n(j,i), nzb_si
[1353]	1450	l_wall(k,j+1,i) = MIN( l_wall(k,j+1,i), 0.5_wp * dy )
[1]	1451	ENDDO
	1452	!
	1453	!-- Above North wall (yz distance)
	1454	DO k = nzb_si + 1, nzb_si + vi
[1353]	1455	l_wall(k,j+1,i) = MIN( l_wall(k,j+1,i), &
	1456	SQRT( 0.25_wp * dy**2 + &
[1]	1457	( zu(k) - zw(nzb_si) )**2 ) )
	1458	ENDDO
	1459	!
	1460	!-- Northleft corner (xy distance)
	1461	IF ( corner_nl(j,i) > 0 ) THEN
	1462	DO k = corner_nl(j,i), nzb_si
	1463	l_wall(k,j+1,i-1) = MIN( l_wall(k,j+1,i-1), &
[1353]	1464	0.5_wp * SQRT( dx2 + dy2 ) )
[1]	1465	ENDDO
	1466	!
	1467	!-- Above Northleft corner (xyz distance)
	1468	DO k = nzb_si + 1, nzb_si + vi
[1353]	1469	l_wall(k,j+1,i-1) = MIN( l_wall(k,j+1,i-1), &
	1470	SQRT( 0.25_wp * (dx2 + dy2) + &
	1471	( zu(k) - zw(nzb_si) )**2 ) )
[1]	1472	ENDDO
	1473	ENDIF
	1474	!
	1475	!-- Northright corner (xy distance)
	1476	IF ( corner_nr(j,i) > 0 ) THEN
	1477	DO k = corner_nr(j,i), nzb_si
[1353]	1478	l_wall(k,j+1,i+1) = MIN( l_wall(k,j+1,i+1), &
	1479	0.5_wp * SQRT( dx2 + dy2 ) )
[1]	1480	ENDDO
	1481	!
	1482	!-- Above northright corner (xyz distance)
	1483	DO k = nzb_si + 1, nzb_si + vi
[1353]	1484	l_wall(k,j+1,i+1) = MIN( l_wall(k,j+1,i+1), &
	1485	SQRT( 0.25_wp * (dx2 + dy2) + &
	1486	( zu(k) - zw(nzb_si) )**2 ) )
[1]	1487	ENDDO
	1488	ENDIF
	1489	ENDIF
	1490
	1491	IF ( wall_s(j,i) > 0 ) THEN
	1492	!
	1493	!-- South wall (y distance)
	1494	DO k = wall_s(j,i), nzb_si
[1353]	1495	l_wall(k,j-1,i) = MIN( l_wall(k,j-1,i), 0.5_wp * dy )
[1]	1496	ENDDO
	1497	!
	1498	!-- Above south wall (yz distance)
[1353]	1499	DO k = nzb_si + 1, nzb_si + vi
	1500	l_wall(k,j-1,i) = MIN( l_wall(k,j-1,i), &
	1501	SQRT( 0.25_wp * dy**2 + &
[1]	1502	( zu(k) - zw(nzb_si) )**2 ) )
	1503	ENDDO
	1504	!
	1505	!-- Southleft corner (xy distance)
	1506	IF ( corner_sl(j,i) > 0 ) THEN
	1507	DO k = corner_sl(j,i), nzb_si
[1353]	1508	l_wall(k,j-1,i-1) = MIN( l_wall(k,j-1,i-1), &
	1509	0.5_wp * SQRT( dx2 + dy2 ) )
[1]	1510	ENDDO
	1511	!
	1512	!-- Above southleft corner (xyz distance)
	1513	DO k = nzb_si + 1, nzb_si + vi
[1353]	1514	l_wall(k,j-1,i-1) = MIN( l_wall(k,j-1,i-1), &
	1515	SQRT( 0.25_wp * (dx2 + dy2) + &
	1516	( zu(k) - zw(nzb_si) )**2 ) )
[1]	1517	ENDDO
	1518	ENDIF
	1519	!
	1520	!-- Southright corner (xy distance)
	1521	IF ( corner_sr(j,i) > 0 ) THEN
	1522	DO k = corner_sr(j,i), nzb_si
[1353]	1523	l_wall(k,j-1,i+1) = MIN( l_wall(k,j-1,i+1), &
	1524	0.5_wp * SQRT( dx2 + dy2 ) )
[1]	1525	ENDDO
	1526	!
	1527	!-- Above southright corner (xyz distance)
	1528	DO k = nzb_si + 1, nzb_si + vi
[1353]	1529	l_wall(k,j-1,i+1) = MIN( l_wall(k,j-1,i+1), &
	1530	SQRT( 0.25_wp * (dx2 + dy2) + &
	1531	( zu(k) - zw(nzb_si) )**2 ) )
[1]	1532	ENDDO
	1533	ENDIF
	1534
	1535	ENDIF
	1536
	1537	IF ( wall_l(j,i) > 0 ) THEN
	1538	!
	1539	!-- Left wall (x distance)
	1540	DO k = wall_l(j,i), nzb_si
[1353]	1541	l_wall(k,j,i-1) = MIN( l_wall(k,j,i-1), 0.5_wp * dx )
[1]	1542	ENDDO
	1543	!
	1544	!-- Above left wall (xz distance)
	1545	DO k = nzb_si + 1, nzb_si + vi
[1353]	1546	l_wall(k,j,i-1) = MIN( l_wall(k,j,i-1), &
	1547	SQRT( 0.25_wp * dx**2 + &
	1548	( zu(k) - zw(nzb_si) )**2 ) )
[1]	1549	ENDDO
	1550	ENDIF
	1551
	1552	IF ( wall_r(j,i) > 0 ) THEN
	1553	!
	1554	!-- Right wall (x distance)
	1555	DO k = wall_r(j,i), nzb_si
[1353]	1556	l_wall(k,j,i+1) = MIN( l_wall(k,j,i+1), 0.5_wp * dx )
[1]	1557	ENDDO
	1558	!
	1559	!-- Above right wall (xz distance)
	1560	DO k = nzb_si + 1, nzb_si + vi
[1353]	1561	l_wall(k,j,i+1) = MIN( l_wall(k,j,i+1), &
	1562	SQRT( 0.25_wp * dx**2 + &
[1]	1563	( zu(k) - zw(nzb_si) )**2 ) )
	1564	ENDDO
	1565
	1566	ENDIF
	1567
	1568	ENDDO
	1569	ENDDO
	1570
	1571	ENDIF
	1572
	1573	!
	1574	!-- Multiplication with wall_adjustment_factor
	1575	l_wall = wall_adjustment_factor * l_wall
	1576
	1577	!
[709]	1578	!-- Set lateral boundary conditions for l_wall
[667]	1579	CALL exchange_horiz( l_wall, nbgp )
	1580
[1]	1581	DEALLOCATE( corner_nl, corner_nr, corner_sl, corner_sr, nzb_local, &
[1968]	1582	vertical_influence, wall_l, wall_n, wall_r, wall_s )
[1]	1583
	1584
	1585	END SUBROUTINE init_grid

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