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source: palm/trunk/SOURCE/synthetic_turbulence_generator_mod.f90 @ 4506

Last change on this file since 4506 was 4495, checked in by raasch, 5 years ago
restart data handling with MPI-IO added, first part
Property svn:keywords set to `Id`
File size: 110.5 KB

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1	!> @synthetic_turbulence_generator_mod.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 2017-2020 Leibniz Universitaet Hannover
18	!------------------------------------------------------------------------------!
19	!
20	! Current revisions:
21	! -----------------
22	!
23	!
24	! Former revisions:
25	! -----------------
26	! $Id: synthetic_turbulence_generator_mod.f90 4495 2020-04-13 20:11:20Z schwenkel $
27	! restart data handling with MPI-IO added
28	!
29	! 4481 2020-03-31 18:55:54Z maronga
30	! bugfix: cpp-directives for serial mode added, dummy statements to prevent compile errors added
31	!
32	! 4442 2020-03-04 19:21:13Z suehring
33	! Set back turbulent length scale to 8 x grid spacing in the parametrized mode
34	! (was accidantly changed).
35	!
36	! 4441 2020-03-04 19:20:35Z suehring
37	! Correct misplaced preprocessor directive
38	!
39	! 4438 2020-03-03 20:49:28Z suehring
40	! Performance optimizations in velocity-seed calculation:
41	! - random number array is only defined and computed locally (except for
42	! normalization to zero mean and unit variance)
43	! - parallel random number generator is applied independent on the 2D random
44	! numbers in other routines
45	! - option to decide wheter velocity seeds are computed locally without any
46	! further communication or are computed by all processes along the
47	! communicator
48	!
49	! 4346 2019-12-18 11:55:56Z motisi
50	! Introduction of wall_flags_total_0, which currently sets bits based on static
51	! topography information used in wall_flags_static_0
52	!
53	! 4335 2019-12-12 16:39:05Z suehring
54	! Commentation of last commit
55	!
56	! 4332 2019-12-10 19:44:12Z suehring
57	! Limit initial velocity seeds in restart runs, if not the seed calculation
58	! may become unstable. Further, minor bugfix in initial velocity seed
59	! calculation.
60	!
61	! 4329 2019-12-10 15:46:36Z motisi
62	! Renamed wall_flags_0 to wall_flags_static_0
63	!
64	! 4309 2019-11-26 18:49:59Z suehring
65	! Computation of velocity seeds optimized. This implies that random numbers
66	! are computed now using the parallel random number generator. Random numbers
67	! are now only computed and normalized locally, while distributed over all
68	! mpi ranks afterwards, instead of computing random numbers on a global array.
69	! Further, the number of calls for the time-consuming velocity-seed generation
70	! is reduced - now the left and right, as well as the north and south boundary
71	! share the same velocity-seed matrices.
72	!
73	! 4182 2019-08-22 15:20:23Z scharf
74	! Corrected "Former revisions" section
75	!
76	! 4148 2019-08-08 11:26:00Z suehring
77	! Remove unused variable
78	!
79	! 4144 2019-08-06 09:11:47Z raasch
80	! relational operators .EQ., .NE., etc. replaced by ==, /=, etc.
81	!
82	! 4071 2019-07-03 20:02:00Z suehring
83	! Bugfix, initialize mean_inflow_profiles in case turbulence and inflow
84	! information is not read from file.
85	!
86	! 4022 2019-06-12 11:52:39Z suehring
87	! Several bugfixes and improvements
88	! - revise bias correction of the imposed perturbations (correction via volume
89	! flow can create instabilities in case the mean volume flow is close to zero)
90	! - introduce lower limits in calculation of coefficient matrix, else the
91	! calculation may become numerically unstable
92	! - impose perturbations every timestep, even though no new set of perturbations
93	! is generated in case dt_stg_call /= dt_3d
94	! - Implement a gradual decrease of Reynolds stress and length scales above
95	! ABL height (within 1 length scale above ABL depth to 1/10) rather than a
96	! discontinuous decrease
97	! - Bugfix in non-nested case: use ABL height for parametrized turbulence
98	!
99	! 3987 2019-05-22 09:52:13Z kanani
100	! Introduce alternative switch for debug output during timestepping
101	!
102	! 3938 2019-04-29 16:06:25Z suehring
103	! Remove unused variables
104	!
105	! 3937 2019-04-29 15:09:07Z suehring
106	! Minor bugfix in case of a very early restart where mc_factor is sill not
107	! present.
108	! Some modification and fixing of potential bugs in the calculation of scaling
109	! parameters used for synthetic turbulence parametrization.
110	!
111	! 3909 2019-04-17 09:13:25Z suehring
112	! Minor bugfix for last commit
113	!
114	! 3900 2019-04-16 15:17:43Z suehring
115	! Missing re-calculation of perturbation seeds in case of restarts
116	!
117	! 3891 2019-04-12 17:52:01Z suehring
118	! Bugfix in initialization in case of restart runs.
119	!
120	! 3885 2019-04-11 11:29:34Z kanani
121	! Changes related to global restructuring of location messages and introduction
122	! of additional debug messages
123	!
124	!
125	! removed unused variables
126	!
127	! 3719 2019-02-06 13:10:18Z kanani
128	! Removed log_point measurement from stg_init, since this part is counted to
129	! log_point(2) 'initialisation' already. Moved other log_points to calls of
130	! the subroutines in time_integration for better overview.
131	!
132	! 2259 2017-06-08 09:09:11Z gronemeier
133	! Initial revision
134	!
135	! Authors:
136	! --------
137	! @author Tobias Gronemeier, Matthias Suehring, Atsushi Inagaki, Micha Gryschka, Christoph Knigge
138	!
139	!
140	! Description:
141	! ------------
142	!> The module generates turbulence at the inflow boundary based on a method by
143	!> Xie and Castro (2008) utilizing a Lund rotation (Lund, 1998) and a mass-flux
144	!> correction by Kim et al. (2013).
145	!> The turbulence is correlated based on length scales in y- and z-direction and
146	!> a time scale for each velocity component. The profiles of length and time
147	!> scales, mean u, v, w, e and pt, and all components of the Reynolds stress
148	!> tensor can be either read from file STG_PROFILES, or will be parametrized
149	!> within the boundary layer.
150	!>
151	!> @todo test restart
152	!> enable cyclic_fill
153	!> implement turbulence generation for e and pt
154	!> @todo Input of height-constant length scales via namelist
155	!> @note <Enter notes on the module>
156	!> @bug Height information from input file is not used. Profiles from input
157	!> must match with current PALM grid.
158	!> In case of restart, velocity seeds differ from precursor run if a11,
159	!> a22, or a33 are zero.
160	!------------------------------------------------------------------------------!
161	MODULE synthetic_turbulence_generator_mod
162
163
164	USE arrays_3d, &
165	ONLY: dzw, &
166	ddzw, &
167	drho_air, &
168	mean_inflow_profiles, &
169	q, &
170	q_init, &
171	pt, &
172	pt_init, &
173	u, &
174	u_init, &
175	v, &
176	v_init, &
177	w, &
178	zu, &
179	zw
180
181	USE basic_constants_and_equations_mod, &
182	ONLY: g, &
183	kappa, &
184	pi
185
186	USE control_parameters, &
187	ONLY: bc_lr, &
188	bc_ns, &
189	child_domain, &
190	coupling_char, &
191	debug_output_timestep, &
192	dt_3d, &
193	e_init, &
194	humidity, &
195	initializing_actions, &
196	intermediate_timestep_count, &
197	intermediate_timestep_count_max, &
198	length, &
199	message_string, &
200	nesting_offline, &
201	neutral, &
202	num_mean_inflow_profiles, &
203	random_generator, &
204	rans_mode, &
205	restart_data_format_output, &
206	restart_string, &
207	syn_turb_gen, &
208	time_since_reference_point, &
209	turbulent_inflow
210
211	USE cpulog, &
212	ONLY: cpu_log, &
213	log_point_s
214
215	USE grid_variables, &
216	ONLY: ddx, &
217	ddy, &
218	dx, &
219	dy
220
221	USE indices, &
222	ONLY: nbgp, &
223	nz, &
224	nzb, &
225	nzt, &
226	nx, &
227	nxl, &
228	nxlu, &
229	nxr, &
230	ny, &
231	nys, &
232	nysv, &
233	nyn, &
234	wall_flags_total_0
235
236	USE kinds
237
238	#if defined( __parallel ) && !defined( __mpifh )
239	USE MPI
240	#endif
241
242	USE nesting_offl_mod, &
243	ONLY: nesting_offl_calc_zi, &
244	zi_ribulk
245
246	USE pegrid, &
247	ONLY: comm1dx, &
248	comm1dy, &
249	comm2d, &
250	ierr, &
251	myidx, &
252	myidy, &
253	pdims
254
255	USE pmc_interface, &
256	ONLY : rans_mode_parent
257
258	USE random_generator_parallel, &
259	ONLY: init_parallel_random_generator, &
260	random_dummy, &
261	random_number_parallel, &
262	random_seed_parallel
263
264	USE restart_data_mpi_io_mod, &
265	ONLY: rrd_mpi_io, &
266	wrd_mpi_io
267
268	USE transpose_indices, &
269	ONLY: nzb_x, &
270	nzt_x
271
272	USE surface_mod, &
273	ONLY: surf_def_h, &
274	surf_lsm_h, &
275	surf_usm_h
276
277	IMPLICIT NONE
278
279	#if defined( __parallel ) && defined( __mpifh )
280	INCLUDE "mpif.h"
281	#endif
282
283
284	LOGICAL :: velocity_seed_initialized = .FALSE. !< true after first call of stg_main
285	LOGICAL :: parametrize_inflow_turbulence = .FALSE. !< flag indicating that inflow turbulence is either read from file (.FALSE.) or if it parametrized
286	LOGICAL :: use_syn_turb_gen = .FALSE. !< switch to use synthetic turbulence generator
287	LOGICAL :: compute_velocity_seeds_local = .TRUE. !< switch to decide whether velocity seeds are computed locally or if computation
288	!< is distributed over several processes
289
290	INTEGER(iwp) :: id_stg_left !< left lateral boundary core id in case of turbulence generator
291	INTEGER(iwp) :: id_stg_north !< north lateral boundary core id in case of turbulence generator
292	INTEGER(iwp) :: id_stg_right !< right lateral boundary core id in case of turbulence generator
293	INTEGER(iwp) :: id_stg_south !< south lateral boundary core id in case of turbulence generator
294	INTEGER(iwp) :: mergp !< maximum length scale (in gp)
295	INTEGER(iwp) :: nzb_x_stg !< lower bound of z coordinate (required for transposing z on PEs along x)
296	INTEGER(iwp) :: nzt_x_stg !< upper bound of z coordinate (required for transposing z on PEs along x)
297	INTEGER(iwp) :: nzb_y_stg !< lower bound of z coordinate (required for transposing z on PEs along y)
298	INTEGER(iwp) :: nzt_y_stg !< upper bound of z coordinate (required for transposing z on PEs along y)
299	#if defined( __parallel )
300	INTEGER(iwp) :: stg_type_xz !< MPI type for full z range
301	INTEGER(iwp) :: stg_type_xz_small !< MPI type for small z range
302	INTEGER(iwp) :: stg_type_yz !< MPI type for full z range
303	INTEGER(iwp) :: stg_type_yz_small !< MPI type for small z range
304	#endif
305
306	INTEGER(iwp), DIMENSION(3) :: nr_non_topo_xz = 0 !< number of non-topography grid points at xz cross-sections,
307	!< required for bias correction of imposed perturbations
308	INTEGER(iwp), DIMENSION(3) :: nr_non_topo_yz = 0 !< number of non-topography grid points at yz cross-sections,
309	!< required for bias correction of imposed perturbations
310
311	#if defined( __parallel )
312	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displs_xz !< displacement for MPI_GATHERV
313	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: recv_count_xz !< receive count for MPI_GATHERV
314	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: displs_yz !< displacement for MPI_GATHERV
315	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: recv_count_yz !< receive count for MPI_GATHERV
316	#endif
317	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nux !< length scale of u in x direction (in gp)
318	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nuy !< length scale of u in y direction (in gp)
319	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nuz !< length scale of u in z direction (in gp)
320	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nvx !< length scale of v in x direction (in gp)
321	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nvy !< length scale of v in y direction (in gp)
322	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nvz !< length scale of v in z direction (in gp)
323	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nwx !< length scale of w in x direction (in gp)
324	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nwy !< length scale of w in y direction (in gp)
325	INTEGER(iwp), DIMENSION(:), ALLOCATABLE :: nwz !< length scale of w in z direction (in gp)
326
327	INTEGER(isp), DIMENSION(:), ALLOCATABLE :: id_rand_xz !< initial random IDs at xz inflow boundary
328	INTEGER(isp), DIMENSION(:), ALLOCATABLE :: id_rand_yz !< initial random IDs at yz inflow boundary
329	INTEGER(isp), DIMENSION(:,:), ALLOCATABLE :: seq_rand_xz !< initial random seeds at xz inflow boundary
330	INTEGER(isp), DIMENSION(:,:), ALLOCATABLE :: seq_rand_yz !< initial random seeds at yz inflow boundary
331
332	REAL(wp) :: blend !< value to create gradually and smooth blending of Reynolds stress and length
333	!< scales above the boundary layer
334	REAL(wp) :: blend_coeff = -2.3_wp !< coefficient used to ensure that blending functions decreases to 1/10 after
335	!< one length scale above ABL top
336	REAL(wp) :: d_l !< blend_coeff/length_scale
337	REAL(wp) :: length_scale !< length scale, default is 8 x minimum grid spacing
338	REAL(wp) :: dt_stg_adjust = 300.0_wp !< time interval for adjusting turbulence statistics
339	REAL(wp) :: dt_stg_call = 0.0_wp !< time interval for calling synthetic turbulence generator
340	REAL(wp) :: scale_l !< scaling parameter used for turbulence parametrization - Obukhov length
341	REAL(wp) :: scale_us !< scaling parameter used for turbulence parametrization - friction velocity
342	REAL(wp) :: scale_wm !< scaling parameter used for turbulence parametrization - momentum scale
343	REAL(wp) :: time_stg_adjust = 0.0_wp !< time counter for adjusting turbulence information
344	REAL(wp) :: time_stg_call = 0.0_wp !< time counter for calling generator
345
346	REAL(wp), DIMENSION(3) :: mc_factor = 1.0_wp !< correction factor for the u,v,w-components to maintain original mass flux
347
348
349	REAL(wp),DIMENSION(:), ALLOCATABLE :: r11 !< Reynolds parameter
350	REAL(wp),DIMENSION(:), ALLOCATABLE :: r21 !< Reynolds parameter
351	REAL(wp),DIMENSION(:), ALLOCATABLE :: r22 !< Reynolds parameter
352	REAL(wp),DIMENSION(:), ALLOCATABLE :: r31 !< Reynolds parameter
353	REAL(wp),DIMENSION(:), ALLOCATABLE :: r32 !< Reynolds parameter
354	REAL(wp),DIMENSION(:), ALLOCATABLE :: r33 !< Reynolds parameter
355
356	REAL(wp), DIMENSION(:), ALLOCATABLE :: a11 !< coefficient for Lund rotation
357	REAL(wp), DIMENSION(:), ALLOCATABLE :: a21 !< coefficient for Lund rotation
358	REAL(wp), DIMENSION(:), ALLOCATABLE :: a22 !< coefficient for Lund rotation
359	REAL(wp), DIMENSION(:), ALLOCATABLE :: a31 !< coefficient for Lund rotation
360	REAL(wp), DIMENSION(:), ALLOCATABLE :: a32 !< coefficient for Lund rotation
361	REAL(wp), DIMENSION(:), ALLOCATABLE :: a33 !< coefficient for Lund rotation
362	REAL(wp), DIMENSION(:), ALLOCATABLE :: tu !< Lagrangian time scale of u
363	REAL(wp), DIMENSION(:), ALLOCATABLE :: tv !< Lagrangian time scale of v
364	REAL(wp), DIMENSION(:), ALLOCATABLE :: tw !< Lagrangian time scale of w
365
366	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: bux !< filter function for u in x direction
367	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: buy !< filter function for u in y direction
368	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: buz !< filter function for u in z direction
369	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: bvx !< filter function for v in x direction
370	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: bvy !< filter function for v in y direction
371	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: bvz !< filter function for v in z direction
372	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: bwx !< filter function for w in y direction
373	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: bwy !< filter function for w in y direction
374	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: bwz !< filter function for w in z direction
375	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fu_xz !< velocity seed for u at xz plane
376	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fuo_xz !< velocity seed for u at xz plane with new random number
377	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fu_yz !< velocity seed for u at yz plane
378	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fuo_yz !< velocity seed for u at yz plane with new random number
379	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fv_xz !< velocity seed for v at xz plane
380	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fvo_xz !< velocity seed for v at xz plane with new random number
381	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fv_yz !< velocity seed for v at yz plane
382	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fvo_yz !< velocity seed for v at yz plane with new random number
383	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fw_xz !< velocity seed for w at xz plane
384	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fwo_xz !< velocity seed for w at xz plane with new random number
385	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fw_yz !< velocity seed for w at yz plane
386	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: fwo_yz !< velocity seed for w at yz plane with new random number
387
388	REAL(wp), DIMENSION(:,:,:), ALLOCATABLE :: dist_xz !< imposed disturbances at north/south boundary
389	REAL(wp), DIMENSION(:,:,:), ALLOCATABLE :: dist_yz !< imposed disturbances at north/south boundary
390
391	!
392	!-- PALM interfaces:
393	!-- Adjust time and lenght scales, Reynolds stress, and filter functions
394	INTERFACE stg_adjust
395	MODULE PROCEDURE stg_adjust
396	END INTERFACE stg_adjust
397	!
398	!-- Input parameter checks to be done in check_parameters
399	INTERFACE stg_check_parameters
400	MODULE PROCEDURE stg_check_parameters
401	END INTERFACE stg_check_parameters
402
403	!
404	!-- Calculate filter functions
405	INTERFACE stg_filter_func
406	MODULE PROCEDURE stg_filter_func
407	END INTERFACE stg_filter_func
408
409	!
410	!-- Generate velocity seeds at south and north domain boundary
411	INTERFACE stg_generate_seed_xz
412	MODULE PROCEDURE stg_generate_seed_xz
413	END INTERFACE stg_generate_seed_xz
414	!
415	!-- Generate velocity seeds at left and/or right domain boundary
416	INTERFACE stg_generate_seed_yz
417	MODULE PROCEDURE stg_generate_seed_yz
418	END INTERFACE stg_generate_seed_yz
419
420	!
421	!-- Output of information to the header file
422	INTERFACE stg_header
423	MODULE PROCEDURE stg_header
424	END INTERFACE stg_header
425
426	!
427	!-- Initialization actions
428	INTERFACE stg_init
429	MODULE PROCEDURE stg_init
430	END INTERFACE stg_init
431
432	!
433	!-- Main procedure of synth. turb. gen.
434	INTERFACE stg_main
435	MODULE PROCEDURE stg_main
436	END INTERFACE stg_main
437
438	!
439	!-- Reading of NAMELIST parameters
440	INTERFACE stg_parin
441	MODULE PROCEDURE stg_parin
442	END INTERFACE stg_parin
443
444	!
445	!-- Reading of parameters for restart runs
446	INTERFACE stg_rrd_global
447	MODULE PROCEDURE stg_rrd_global_ftn
448	MODULE PROCEDURE stg_rrd_global_mpi
449	END INTERFACE stg_rrd_global
450
451	!
452	!-- Writing of binary output for restart runs
453	INTERFACE stg_wrd_global
454	MODULE PROCEDURE stg_wrd_global
455	END INTERFACE stg_wrd_global
456
457	SAVE
458
459	PRIVATE
460
461	!
462	!-- Public interfaces
463	PUBLIC stg_adjust, stg_check_parameters, stg_header, stg_init, stg_main, &
464	stg_parin, stg_rrd_global, stg_wrd_global
465
466	!
467	!-- Public variables
468	PUBLIC dt_stg_call, dt_stg_adjust, id_stg_left, id_stg_north, &
469	id_stg_right, id_stg_south, parametrize_inflow_turbulence, &
470	time_stg_adjust, time_stg_call, use_syn_turb_gen
471
472
473	CONTAINS
474
475
476	!------------------------------------------------------------------------------!
477	! Description:
478	! ------------
479	!> Check parameters routine for synthetic turbulence generator
480	!------------------------------------------------------------------------------!
481	SUBROUTINE stg_check_parameters
482
483	IF ( .NOT. use_syn_turb_gen .AND. .NOT. rans_mode .AND. &
484	nesting_offline ) THEN
485	message_string = 'Synthetic turbulence generator is required ' // &
486	'if offline nesting is applied and PALM operates ' // &
487	'in LES mode.'
488	CALL message( 'stg_check_parameters', 'PA0520', 0, 0, 0, 6, 0 )
489	ENDIF
490
491	IF ( .NOT. use_syn_turb_gen .AND. child_domain &
492	.AND. rans_mode_parent .AND. .NOT. rans_mode ) THEN
493	message_string = 'Synthetic turbulence generator is required ' // &
494	'when nesting is applied and parent operates in ' // &
495	'RANS-mode but current child in LES mode.'
496	CALL message( 'stg_check_parameters', 'PA0524', 1, 2, 0, 6, 0 )
497	ENDIF
498
499	IF ( use_syn_turb_gen ) THEN
500
501	IF ( child_domain .AND. .NOT. rans_mode .AND. &
502	.NOT. rans_mode_parent ) THEN
503	message_string = 'Using synthetic turbulence generator ' // &
504	'is not allowed in LES-LES nesting.'
505	CALL message( 'stg_check_parameters', 'PA0620', 1, 2, 0, 6, 0 )
506
507	ENDIF
508
509	IF ( child_domain .AND. rans_mode .AND. &
510	rans_mode_parent ) THEN
511	message_string = 'Using synthetic turbulence generator ' // &
512	'is not allowed in RANS-RANS nesting.'
513	CALL message( 'stg_check_parameters', 'PA0621', 1, 2, 0, 6, 0 )
514
515	ENDIF
516
517	IF ( .NOT. nesting_offline .AND. .NOT. child_domain ) THEN
518
519	IF ( INDEX( initializing_actions, 'set_constant_profiles' ) == 0 &
520	.AND. INDEX( initializing_actions, 'read_restart_data' ) == 0 ) THEN
521	message_string = 'Using synthetic turbulence generator ' // &
522	'requires %initializing_actions = ' // &
523	'"set_constant_profiles" or "read_restart_data"' //&
524	', if not offline nesting is applied.'
525	CALL message( 'stg_check_parameters', 'PA0015', 1, 2, 0, 6, 0 )
526	ENDIF
527
528	IF ( bc_lr /= 'dirichlet/radiation' ) THEN
529	message_string = 'Using synthetic turbulence generator ' // &
530	'requires &bc_lr = "dirichlet/radiation", ' // &
531	'if not offline nesting is applied.'
532	CALL message( 'stg_check_parameters', 'PA0035', 1, 2, 0, 6, 0 )
533	ENDIF
534	IF ( bc_ns /= 'cyclic' ) THEN
535	message_string = 'Using synthetic turbulence generator ' // &
536	'requires &bc_ns = "cyclic", ' // &
537	'if not offline nesting is applied.'
538	CALL message( 'stg_check_parameters', 'PA0037', 1, 2, 0, 6, 0 )
539	ENDIF
540
541	ENDIF
542
543	IF ( turbulent_inflow ) THEN
544	message_string = 'Using synthetic turbulence generator ' // &
545	'in combination &with turbulent_inflow = .T. '// &
546	'is not allowed'
547	CALL message( 'stg_check_parameters', 'PA0039', 1, 2, 0, 6, 0 )
548	ENDIF
549	!
550	!-- Synthetic turbulence generator requires the parallel random generator
551	IF ( random_generator /= 'random-parallel' ) THEN
552	message_string = 'Using synthetic turbulence generator ' // &
553	'requires random_generator = random-parallel.'
554	CALL message( 'stg_check_parameters', 'PA0421', 1, 2, 0, 6, 0 )
555	ENDIF
556
557	ENDIF
558
559	END SUBROUTINE stg_check_parameters
560
561
562	!------------------------------------------------------------------------------!
563	! Description:
564	! ------------
565	!> Header output for synthetic turbulence generator
566	!------------------------------------------------------------------------------!
567	SUBROUTINE stg_header ( io )
568
569	INTEGER(iwp), INTENT(IN) :: io !< Unit of the output file
570
571	!
572	!-- Write synthetic turbulence generator Header
573	WRITE( io, 1 )
574	IF ( use_syn_turb_gen ) THEN
575	WRITE( io, 2 )
576	ELSE
577	WRITE( io, 3 )
578	ENDIF
579
580	IF ( parametrize_inflow_turbulence ) THEN
581	WRITE( io, 4 ) dt_stg_adjust
582	ELSE
583	WRITE( io, 5 )
584	ENDIF
585
586	1 FORMAT (//' Synthetic turbulence generator information:'/ &
587	' ------------------------------------------'/)
588	2 FORMAT (' synthetic turbulence generator is switched on')
589	3 FORMAT (' synthetic turbulence generator is switched off')
590	4 FORMAT (' imposed turbulence statistics are parametrized and ajdusted to boundary-layer development each ', F8.2, ' s' )
591	5 FORMAT (' imposed turbulence is read from file' )
592
593	END SUBROUTINE stg_header
594
595
596	!------------------------------------------------------------------------------!
597	! Description:
598	! ------------
599	!> Initialization of the synthetic turbulence generator
600	!------------------------------------------------------------------------------!
601	SUBROUTINE stg_init
602
603	LOGICAL :: file_stg_exist = .FALSE. !< flag indicating whether parameter file for Reynolds stress and length scales exist
604
605	#if defined( __parallel )
606	INTEGER(KIND=MPI_ADDRESS_KIND) :: extent !< extent of new MPI type
607	INTEGER(KIND=MPI_ADDRESS_KIND) :: tob=0 !< dummy variable
608	#endif
609
610	INTEGER(iwp) :: i !> grid index in x-direction
611	INTEGER(iwp) :: j !> loop index
612	INTEGER(iwp) :: k !< index
613	#if defined( __parallel )
614	INTEGER(iwp) :: newtype !< dummy MPI type
615	INTEGER(iwp) :: realsize !< size of REAL variables
616	#endif
617
618	INTEGER(iwp), DIMENSION(3) :: nr_non_topo_xz_l = 0 !< number of non-topography grid points at xz-cross-section on subdomain
619	INTEGER(iwp), DIMENSION(3) :: nr_non_topo_yz_l = 0 !< number of non-topography grid points at yz-cross-section on subdomain
620	!
621	!-- Dummy variables used for reading profiles
622	REAL(wp) :: d1 !< u profile
623	REAL(wp) :: d2 !< v profile
624	REAL(wp) :: d3 !< w profile
625	REAL(wp) :: d5 !< e profile
626	REAL(wp) :: luy !< length scale for u in y direction
627	REAL(wp) :: luz !< length scale for u in z direction
628	REAL(wp) :: lvy !< length scale for v in y direction
629	REAL(wp) :: lvz !< length scale for v in z direction
630	REAL(wp) :: lwy !< length scale for w in y direction
631	REAL(wp) :: lwz !< length scale for w in z direction
632	#if defined( __parallel )
633	REAL(wp) :: nnz !< increment used to determine processor decomposition of z-axis along x and y direction
634	#endif
635	REAL(wp) :: zz !< height
636
637
638	#if defined( __parallel )
639	CALL MPI_BARRIER( comm2d, ierr )
640	#endif
641	!
642	!-- Create mpi-datatypes for exchange in case of non-local but distributed
643	!-- computation of the velocity seeds. This option is useful in
644	!-- case large turbulent length scales are present, where the computational
645	!-- effort becomes large and need to be parallelized. For parameterized
646	!-- turbulence the length scales are small and computing the velocity seeds
647	!-- locally is faster (no overhead by communication).
648	IF ( .NOT. compute_velocity_seeds_local ) THEN
649	#if defined( __parallel )
650	!
651	!-- Determine processor decomposition of z-axis along x- and y-direction
652	nnz = nz / pdims(1)
653	nzb_x_stg = 1 + myidx * INT( nnz )
654	nzt_x_stg = ( myidx + 1 ) * INT( nnz )
655
656	IF ( MOD( nz , pdims(1) ) /= 0 .AND. myidx == id_stg_right ) &
657	nzt_x_stg = nzt_x_stg + myidx * ( nnz - INT( nnz ) )
658
659	IF ( nesting_offline .OR. ( child_domain .AND. rans_mode_parent &
660	.AND. .NOT. rans_mode ) ) THEN
661	nnz = nz / pdims(2)
662	nzb_y_stg = 1 + myidy * INT( nnz )
663	nzt_y_stg = ( myidy + 1 ) * INT( nnz )
664
665	IF ( MOD( nz , pdims(2) ) /= 0 .AND. myidy == id_stg_north ) &
666	nzt_y_stg = nzt_y_stg + myidy * ( nnz - INT( nnz ) )
667	ENDIF
668
669	!
670	!-- Define MPI type used in stg_generate_seed_yz to gather vertical splitted
671	!-- velocity seeds
672	CALL MPI_TYPE_SIZE( MPI_REAL, realsize, ierr )
673	extent = 1 * realsize
674	!
675	!-- Set-up MPI datatyp to involve all cores for turbulence generation at yz
676	!-- layer
677	!-- stg_type_yz: yz-slice with vertical bounds nzb:nzt+1
678	CALL MPI_TYPE_CREATE_SUBARRAY( 2, [nzt-nzb+2,nyn-nys+1], &
679	[1,nyn-nys+1], [0,0], MPI_ORDER_FORTRAN, MPI_REAL, newtype, ierr )
680	CALL MPI_TYPE_CREATE_RESIZED( newtype, tob, extent, stg_type_yz, ierr )
681	CALL MPI_TYPE_COMMIT( stg_type_yz, ierr )
682	CALL MPI_TYPE_FREE( newtype, ierr )
683
684	! stg_type_yz_small: yz-slice with vertical bounds nzb_x_stg:nzt_x_stg+1
685	CALL MPI_TYPE_CREATE_SUBARRAY( 2, [nzt_x_stg-nzb_x_stg+2,nyn-nys+1], &
686	[1,nyn-nys+1], [0,0], MPI_ORDER_FORTRAN, MPI_REAL, newtype, ierr )
687	CALL MPI_TYPE_CREATE_RESIZED( newtype, tob, extent, stg_type_yz_small, ierr )
688	CALL MPI_TYPE_COMMIT( stg_type_yz_small, ierr )
689	CALL MPI_TYPE_FREE( newtype, ierr )
690
691	! receive count and displacement for MPI_GATHERV in stg_generate_seed_yz
692	ALLOCATE( recv_count_yz(pdims(1)), displs_yz(pdims(1)) )
693
694	recv_count_yz = nzt_x_stg-nzb_x_stg + 1
695	recv_count_yz(pdims(1)) = recv_count_yz(pdims(1)) + 1
696
697	DO j = 1, pdims(1)
698	displs_yz(j) = 0 + (nzt_x_stg-nzb_x_stg+1) * (j-1)
699	ENDDO
700	!
701	!-- Set-up MPI datatyp to involve all cores for turbulence generation at xz
702	!-- layer
703	!-- stg_type_xz: xz-slice with vertical bounds nzb:nzt+1
704	IF ( nesting_offline .OR. ( child_domain .AND. rans_mode_parent &
705	.AND. .NOT. rans_mode ) ) THEN
706	CALL MPI_TYPE_CREATE_SUBARRAY( 2, [nzt-nzb+2,nxr-nxl+1], &
707	[1,nxr-nxl+1], [0,0], MPI_ORDER_FORTRAN, MPI_REAL, newtype, ierr )
708	CALL MPI_TYPE_CREATE_RESIZED( newtype, tob, extent, stg_type_xz, ierr )
709	CALL MPI_TYPE_COMMIT( stg_type_xz, ierr )
710	CALL MPI_TYPE_FREE( newtype, ierr )
711
712	! stg_type_yz_small: xz-slice with vertical bounds nzb_x_stg:nzt_x_stg+1
713	CALL MPI_TYPE_CREATE_SUBARRAY( 2, [nzt_y_stg-nzb_y_stg+2,nxr-nxl+1], &
714	[1,nxr-nxl+1], [0,0], MPI_ORDER_FORTRAN, MPI_REAL, newtype, ierr )
715	CALL MPI_TYPE_CREATE_RESIZED( newtype, tob, extent, stg_type_xz_small, ierr )
716	CALL MPI_TYPE_COMMIT( stg_type_xz_small, ierr )
717	CALL MPI_TYPE_FREE( newtype, ierr )
718
719	! receive count and displacement for MPI_GATHERV in stg_generate_seed_yz
720	ALLOCATE( recv_count_xz(pdims(2)), displs_xz(pdims(2)) )
721
722	recv_count_xz = nzt_y_stg-nzb_y_stg + 1
723	recv_count_xz(pdims(2)) = recv_count_xz(pdims(2)) + 1
724
725	DO j = 1, pdims(2)
726	displs_xz(j) = 0 + (nzt_y_stg-nzb_y_stg+1) * (j-1)
727	ENDDO
728
729	ENDIF
730	#endif
731	ENDIF
732	!
733	!-- Allocate required arrays.
734	!-- In case no offline nesting or self nesting is used, the arrary
735	!-- mean_inflow profiles is required. Check if it is already allocated, else
736	!-- allocate and initialize it appropriately. Note, in case turbulence and
737	!-- inflow information is read from file, mean_inflow_profiles is already
738	!-- allocated and initialized appropriately.
739	IF ( .NOT. nesting_offline .AND. .NOT. child_domain ) THEN
740	IF ( .NOT. ALLOCATED( mean_inflow_profiles ) ) THEN
741	ALLOCATE( mean_inflow_profiles(nzb:nzt+1,1:num_mean_inflow_profiles) )
742	mean_inflow_profiles = 0.0_wp
743	mean_inflow_profiles(:,1) = u_init
744	mean_inflow_profiles(:,2) = v_init
745	!
746	!-- Even though potential temperature and humidity are not perturbed,
747	!-- they need to be initialized appropriately.
748	IF ( .NOT. neutral ) &
749	mean_inflow_profiles(:,4) = pt_init
750	IF ( humidity ) &
751	mean_inflow_profiles(:,6) = q_init
752	ENDIF
753	ENDIF
754
755	ALLOCATE ( a11(nzb:nzt+1), a21(nzb:nzt+1), a22(nzb:nzt+1), &
756	a31(nzb:nzt+1), a32(nzb:nzt+1), a33(nzb:nzt+1), &
757	nux(nzb:nzt+1), nuy(nzb:nzt+1), nuz(nzb:nzt+1), &
758	nvx(nzb:nzt+1), nvy(nzb:nzt+1), nvz(nzb:nzt+1), &
759	nwx(nzb:nzt+1), nwy(nzb:nzt+1), nwz(nzb:nzt+1), &
760	r11(nzb:nzt+1), r21(nzb:nzt+1), r22(nzb:nzt+1), &
761	r31(nzb:nzt+1), r32(nzb:nzt+1), r33(nzb:nzt+1), &
762	tu(nzb:nzt+1), tv(nzb:nzt+1), tw(nzb:nzt+1) )
763
764	ALLOCATE ( dist_xz(nzb:nzt+1,nxl:nxr,3) )
765	ALLOCATE ( dist_yz(nzb:nzt+1,nys:nyn,3) )
766	dist_xz = 0.0_wp
767	dist_yz = 0.0_wp
768	!
769	!-- Read inflow profile
770	!-- Height levels of profiles in input profile is as follows:
771	!-- zu: luy, luz, tu, lvy, lvz, tv, r11, r21, r22, d1, d2, d5
772	!-- zw: lwy, lwz, tw, r31, r32, r33, d3
773	!-- WARNING: zz is not used at the moment
774	INQUIRE( FILE = 'STG_PROFILES' // TRIM( coupling_char ), &
775	EXIST = file_stg_exist )
776
777	IF ( file_stg_exist ) THEN
778
779	OPEN( 90, FILE='STG_PROFILES'//TRIM( coupling_char ), STATUS='OLD', &
780	FORM='FORMATTED')
781	!
782	!-- Skip header
783	READ( 90, * )
784
785	DO k = nzb+1, nzt+1
786	READ( 90, * ) zz, luy, luz, tu(k), lvy, lvz, tv(k), lwy, lwz, tw(k), &
787	r11(k), r21(k), r22(k), r31(k), r32(k), r33(k), &
788	d1, d2, d3, d5
789
790	!
791	!-- Convert length scales from meter to number of grid points.
792	nuy(k) = INT( luy * ddy )
793	nuz(k) = INT( luz * ddzw(k) )
794	nvy(k) = INT( lvy * ddy )
795	nvz(k) = INT( lvz * ddzw(k) )
796	nwy(k) = INT( lwy * ddy )
797	nwz(k) = INT( lwz * ddzw(k) )
798	!
799	!-- Workaround, assume isotropic turbulence
800	nwx(k) = nwy(k)
801	nvx(k) = nvy(k)
802	nux(k) = nuy(k)
803	!
804	!-- Save Mean inflow profiles
805	IF ( TRIM( initializing_actions ) /= 'read_restart_data' ) THEN
806	mean_inflow_profiles(k,1) = d1
807	mean_inflow_profiles(k,2) = d2
808	! mean_inflow_profiles(k,4) = d4
809	mean_inflow_profiles(k,5) = d5
810	ENDIF
811	ENDDO
812	!
813	!-- Set lenght scales at surface grid point
814	nuy(nzb) = nuy(nzb+1)
815	nuz(nzb) = nuz(nzb+1)
816	nvy(nzb) = nvy(nzb+1)
817	nvz(nzb) = nvz(nzb+1)
818	nwy(nzb) = nwy(nzb+1)
819	nwz(nzb) = nwz(nzb+1)
820
821	CLOSE( 90 )
822	!
823	!-- Calculate coefficient matrix from Reynolds stress tensor
824	!-- (Lund rotation)
825	CALL calc_coeff_matrix
826	!
827	!-- No information about turbulence and its length scales are available.
828	!-- Instead, parametrize turbulence which is imposed at the boundaries.
829	!-- Set flag which indicates that turbulence is parametrized, which is done
830	!-- later when energy-balance models are already initialized. This is
831	!-- because the STG needs information about surface properties such as
832	!-- roughness to build 'realistic' turbulence profiles.
833	ELSE
834	!
835	!-- Define length scale for the imposed turbulence, which is defined as
836	!-- 8 times the minimum grid spacing
837	length_scale = 8.0_wp * MIN( dx, dy, MINVAL( dzw ) )
838	!
839	!-- Define constant to gradually decrease length scales and Reynolds stress
840	!-- above ABL top. Assure that no zero length scales are used.
841	d_l = blend_coeff / MAX( length_scale, dx, dy, MINVAL( dzw ) )
842	!
843	!-- Set flag indicating that turbulence is parametrized
844	parametrize_inflow_turbulence = .TRUE.
845	!
846	!-- In case of dirichlet inflow boundary conditions only at one lateral
847	!-- boundary, i.e. in the case no offline or self nesting is applied but
848	!-- synthetic turbulence shall be parametrized nevertheless, the
849	!-- boundary-layer depth need to determined first.
850	IF ( .NOT. nesting_offline .AND. .NOT. child_domain ) &
851	CALL nesting_offl_calc_zi
852	!
853	!-- Determine boundary-layer depth, which is used to initialize lenght
854	!-- scales
855	CALL calc_scaling_variables
856	!
857	!-- Initialize lenght and time scales, which in turn are used
858	!-- to initialize the filter functions.
859	CALL calc_length_and_time_scale
860	!
861	!-- Parametrize Reynolds-stress tensor, diagonal elements as well
862	!-- as r21 (v'u'), r31 (w'u'), r32 (w'v'). Parametrization follows
863	!-- Rotach et al. (1996) and is based on boundary-layer depth,
864	!-- friction velocity and velocity scale.
865	CALL parametrize_reynolds_stress
866	!
867	!-- Calculate coefficient matrix from Reynolds stress tensor
868	!-- (Lund rotation)
869	CALL calc_coeff_matrix
870
871	ENDIF
872
873	!
874	!-- Assign initial profiles. Note, this is only required if turbulent
875	!-- inflow from the left is desired, not in case of any of the
876	!-- nesting (offline or self nesting) approaches.
877	IF ( .NOT. nesting_offline .AND. .NOT. child_domain ) THEN
878	u_init = mean_inflow_profiles(:,1)
879	v_init = mean_inflow_profiles(:,2)
880	!pt_init = mean_inflow_profiles(:,4)
881	e_init = MAXVAL( mean_inflow_profiles(:,5) )
882	ENDIF
883
884	!
885	!-- Define the size of the filter functions and allocate them.
886	mergp = 0
887
888	! arrays must be large enough to cover the largest length scale
889	DO k = nzb, nzt+1
890	j = MAX( ABS(nux(k)), ABS(nuy(k)), ABS(nuz(k)), &
891	ABS(nvx(k)), ABS(nvy(k)), ABS(nvz(k)), &
892	ABS(nwx(k)), ABS(nwy(k)), ABS(nwz(k)) )
893	IF ( j > mergp ) mergp = j
894	ENDDO
895
896	! mergp = 2 * mergp
897	! mergp = mergp
898
899	ALLOCATE ( bux(-mergp:mergp,nzb:nzt+1), &
900	buy(-mergp:mergp,nzb:nzt+1), &
901	buz(-mergp:mergp,nzb:nzt+1), &
902	bvx(-mergp:mergp,nzb:nzt+1), &
903	bvy(-mergp:mergp,nzb:nzt+1), &
904	bvz(-mergp:mergp,nzb:nzt+1), &
905	bwx(-mergp:mergp,nzb:nzt+1), &
906	bwy(-mergp:mergp,nzb:nzt+1), &
907	bwz(-mergp:mergp,nzb:nzt+1) )
908
909	!
910	!-- Allocate velocity seeds for turbulence at xz-layer
911	ALLOCATE ( fu_xz( nzb:nzt+1,nxl:nxr), fuo_xz(nzb:nzt+1,nxl:nxr), &
912	fv_xz( nzb:nzt+1,nxl:nxr), fvo_xz(nzb:nzt+1,nxl:nxr), &
913	fw_xz( nzb:nzt+1,nxl:nxr), fwo_xz(nzb:nzt+1,nxl:nxr) )
914
915	!
916	!-- Allocate velocity seeds for turbulence at yz-layer
917	ALLOCATE ( fu_yz( nzb:nzt+1,nys:nyn), fuo_yz(nzb:nzt+1,nys:nyn), &
918	fv_yz( nzb:nzt+1,nys:nyn), fvo_yz(nzb:nzt+1,nys:nyn), &
919	fw_yz( nzb:nzt+1,nys:nyn), fwo_yz(nzb:nzt+1,nys:nyn) )
920
921	fu_xz = 0.0_wp
922	fuo_xz = 0.0_wp
923	fv_xz = 0.0_wp
924	fvo_xz = 0.0_wp
925	fw_xz = 0.0_wp
926	fwo_xz = 0.0_wp
927
928	fu_yz = 0.0_wp
929	fuo_yz = 0.0_wp
930	fv_yz = 0.0_wp
931	fvo_yz = 0.0_wp
932	fw_yz = 0.0_wp
933	fwo_yz = 0.0_wp
934
935	!
936	!-- Create filter functions
937	CALL stg_filter_func( nux, bux ) !filter ux
938	CALL stg_filter_func( nuy, buy ) !filter uy
939	CALL stg_filter_func( nuz, buz ) !filter uz
940	CALL stg_filter_func( nvx, bvx ) !filter vx
941	CALL stg_filter_func( nvy, bvy ) !filter vy
942	CALL stg_filter_func( nvz, bvz ) !filter vz
943	CALL stg_filter_func( nwx, bwx ) !filter wx
944	CALL stg_filter_func( nwy, bwy ) !filter wy
945	CALL stg_filter_func( nwz, bwz ) !filter wz
946
947	#if defined( __parallel )
948	CALL MPI_BARRIER( comm2d, ierr )
949	#endif
950
951	!
952	!-- In case of restart, calculate velocity seeds fu, fv, fw from former
953	! time step.
954	! Bug: fu, fv, fw are different in those heights where a11, a22, a33
955	! are 0 compared to the prerun. This is mostly for k=nzt+1.
956	IF ( TRIM( initializing_actions ) == 'read_restart_data' ) THEN
957	IF ( myidx == id_stg_left .OR. myidx == id_stg_right ) THEN
958
959	IF ( myidx == id_stg_left ) i = -1
960	IF ( myidx == id_stg_right ) i = nxr+1
961
962	DO j = nys, nyn
963	DO k = nzb, nzt+1
964	IF ( a11(k) > 10E-8_wp ) THEN
965	fu_yz(k,j) = ( u(k,j,i) - u_init(k) ) / a11(k)
966	ELSE
967	fu_yz(k,j) = 10E-8_wp
968	ENDIF
969
970	IF ( a22(k) > 10E-8_wp ) THEN
971	fv_yz(k,j) = ( v(k,j,i) - &
972	a21(k) * fu_yz(k,j) - v_init(k) ) / a22(k)
973	ELSE
974	fv_yz(k,j) = 10E-8_wp
975	ENDIF
976
977	IF ( a33(k) > 10E-8_wp ) THEN
978	fw_yz(k,j) = ( w(k,j,i) - &
979	a31(k) * fu_yz(k,j) - a32(k) * &
980	fv_yz(k,j) ) / a33(k)
981	ELSE
982	fw_yz(k,j) = 10E-8_wp
983	ENDIF
984	ENDDO
985	ENDDO
986	ENDIF
987
988	IF ( myidy == id_stg_south .OR. myidy == id_stg_north ) THEN
989
990	IF ( myidy == id_stg_south ) j = -1
991	IF ( myidy == id_stg_north ) j = nyn+1
992
993	DO i = nxl, nxr
994	DO k = nzb, nzt+1
995	!
996	!-- In case the correlation coefficients are very small, the
997	!-- velocity seeds may become very large finally creating
998	!-- numerical instabilities in the synthetic turbulence generator.
999	!-- Empirically, a value of 10E-8 seems to be sufficient.
1000	IF ( a11(k) > 10E-8_wp ) THEN
1001	fu_xz(k,i) = ( u(k,j,i) - u_init(k) ) / a11(k)
1002	ELSE
1003	fu_xz(k,i) = 10E-8_wp
1004	ENDIF
1005
1006	IF ( a22(k) > 10E-8_wp ) THEN
1007	fv_xz(k,i) = ( v(k,j,i) - &
1008	a21(k) * fu_xz(k,i) - v_init(k) ) / a22(k)
1009	ELSE
1010	fv_xz(k,i) = 10E-8_wp
1011	ENDIF
1012
1013	IF ( a33(k) > 10E-8_wp ) THEN
1014	fw_xz(k,i) = ( w(k,j,i) - &
1015	a31(k) * fu_xz(k,i) - &
1016	a32(k) * fv_xz(k,i) ) / a33(k)
1017	ELSE
1018	fw_xz(k,i) = 10E-8_wp
1019	ENDIF
1020
1021	ENDDO
1022	ENDDO
1023	ENDIF
1024	ENDIF
1025	!
1026	!-- Count the number of non-topography grid points at the boundaries where
1027	!-- perturbations are imposed. This number is later used for bias corrections
1028	!-- of the perturbations, i.e. to force that their mean is zero. Please note,
1029	!-- due to the asymetry of u and v along x and y direction, respectively,
1030	!-- different cases must be distinguished.
1031	IF ( myidx == id_stg_left .OR. myidx == id_stg_right ) THEN
1032	!
1033	!-- Number of grid points where perturbations are imposed on u
1034	IF ( myidx == id_stg_left ) i = nxl
1035	IF ( myidx == id_stg_right ) i = nxr+1
1036
1037	nr_non_topo_yz_l(1) = SUM( &
1038	MERGE( 1, 0, &
1039	BTEST( wall_flags_total_0(nzb:nzt,nys:nyn,i), 1 ) ) )
1040	!
1041	!-- Number of grid points where perturbations are imposed on v and w
1042	IF ( myidx == id_stg_left ) i = nxl-1
1043	IF ( myidx == id_stg_right ) i = nxr+1
1044
1045	nr_non_topo_yz_l(2) = SUM( &
1046	MERGE( 1, 0, &
1047	BTEST( wall_flags_total_0(nzb:nzt,nysv:nyn,i), 2 ) ) )
1048	nr_non_topo_yz_l(3) = SUM( &
1049	MERGE( 1, 0, &
1050	BTEST( wall_flags_total_0(nzb:nzt,nys:nyn,i), 3 ) ) )
1051
1052	#if defined( __parallel )
1053	CALL MPI_ALLREDUCE( nr_non_topo_yz_l, nr_non_topo_yz, 3, MPI_INTEGER, &
1054	MPI_SUM, comm1dy, ierr )
1055	#else
1056	nr_non_topo_yz = nr_non_topo_yz_l
1057	#endif
1058	ENDIF
1059
1060	IF ( myidy == id_stg_south .OR. myidy == id_stg_north ) THEN
1061	!
1062	!-- Number of grid points where perturbations are imposed on v
1063	IF ( myidy == id_stg_south ) j = nys
1064	IF ( myidy == id_stg_north ) j = nyn+1
1065
1066	nr_non_topo_xz_l(2) = SUM( &
1067	MERGE( 1, 0, &
1068	BTEST( wall_flags_total_0(nzb:nzt,j,nxl:nxr), 2 ) ) )
1069	!
1070	!-- Number of grid points where perturbations are imposed on u and w
1071	IF ( myidy == id_stg_south ) j = nys-1
1072	IF ( myidy == id_stg_north ) j = nyn+1
1073
1074	nr_non_topo_xz_l(1) = SUM( &
1075	MERGE( 1, 0, &
1076	BTEST( wall_flags_total_0(nzb:nzt,j,nxlu:nxr), 1 ) ) )
1077	nr_non_topo_xz_l(3) = SUM( &
1078	MERGE( 1, 0, &
1079	BTEST( wall_flags_total_0(nzb:nzt,j,nxl:nxr), 3 ) ) )
1080
1081	#if defined( __parallel )
1082	CALL MPI_ALLREDUCE( nr_non_topo_xz_l, nr_non_topo_xz, 3, MPI_INTEGER, &
1083	MPI_SUM, comm1dx, ierr )
1084	#else
1085	nr_non_topo_xz = nr_non_topo_xz_l
1086	#endif
1087	ENDIF
1088	!
1089	!-- Initialize random number generator at xz- and yz-layers. Random numbers
1090	!-- are initialized at each core. In case there is only inflow from the left,
1091	!-- it is sufficient to generate only random numbers for the yz-layer, else
1092	!-- random numbers for the xz-layer are also required.
1093	ALLOCATE ( id_rand_yz(-mergp+nys:nyn+mergp) )
1094	ALLOCATE ( seq_rand_yz(5,-mergp+nys:nyn+mergp) )
1095	id_rand_yz = 0
1096	seq_rand_yz = 0
1097
1098	CALL init_parallel_random_generator( ny, -mergp+nys, nyn+mergp, &
1099	id_rand_yz, seq_rand_yz )
1100
1101	IF ( nesting_offline .OR. ( child_domain .AND. rans_mode_parent &
1102	.AND. .NOT. rans_mode ) ) THEN
1103	ALLOCATE ( id_rand_xz(-mergp+nxl:nxr+mergp) )
1104	ALLOCATE ( seq_rand_xz(5,-mergp+nxl:nxr+mergp) )
1105	id_rand_xz = 0
1106	seq_rand_xz = 0
1107
1108	CALL init_parallel_random_generator( nx, -mergp+nxl, nxr+mergp, &
1109	id_rand_xz, seq_rand_xz )
1110	ENDIF
1111
1112
1113
1114	END SUBROUTINE stg_init
1115
1116
1117	!------------------------------------------------------------------------------!
1118	! Description:
1119	! ------------
1120	!> Calculate filter function bxx from length scale nxx following Eg.9 and 10
1121	!> (Xie and Castro, 2008)
1122	!------------------------------------------------------------------------------!
1123	SUBROUTINE stg_filter_func( nxx, bxx )
1124
1125	INTEGER(iwp) :: k !< loop index
1126	INTEGER(iwp) :: n_k !< length scale nXX in height k
1127	INTEGER(iwp) :: nf !< index for length scales
1128
1129	REAL(wp) :: bdenom !< denominator for filter functions bXX
1130	REAL(wp) :: qsi = 1.0_wp !< minimization factor
1131
1132	INTEGER(iwp), DIMENSION(nzb:nzt+1) :: nxx !< length scale (in gp)
1133
1134	REAL(wp), DIMENSION(-mergp:mergp,nzb:nzt+1) :: bxx !< filter function
1135
1136
1137	bxx = 0.0_wp
1138
1139	DO k = nzb, nzt+1
1140	bdenom = 0.0_wp
1141	n_k = nxx(k)
1142	IF ( n_k /= 0 ) THEN
1143
1144	!
1145	!-- ( Eq.10 )^2
1146	DO nf = -n_k, n_k
1147	bdenom = bdenom + EXP( -qsi * pi * ABS(nf) / n_k )**2
1148	ENDDO
1149
1150	!
1151	!-- ( Eq.9 )
1152	bdenom = SQRT( bdenom )
1153	DO nf = -n_k, n_k
1154	bxx(nf,k) = EXP( -qsi * pi * ABS(nf) / n_k ) / bdenom
1155	ENDDO
1156	ENDIF
1157	ENDDO
1158
1159	END SUBROUTINE stg_filter_func
1160
1161
1162	!------------------------------------------------------------------------------!
1163	! Description:
1164	! ------------
1165	!> Parin for &stg_par for synthetic turbulence generator
1166	!------------------------------------------------------------------------------!
1167	SUBROUTINE stg_parin
1168
1169	CHARACTER (LEN=80) :: line !< dummy string that contains the current line of the parameter file
1170
1171
1172	NAMELIST /stg_par/ dt_stg_adjust, &
1173	dt_stg_call, &
1174	use_syn_turb_gen, &
1175	compute_velocity_seeds_local
1176
1177	line = ' '
1178	!
1179	!-- Try to find stg package
1180	REWIND ( 11 )
1181	line = ' '
1182	DO WHILE ( INDEX( line, '&stg_par' ) == 0 )
1183	READ ( 11, '(A)', END=20 ) line
1184	ENDDO
1185	BACKSPACE ( 11 )
1186
1187	!
1188	!-- Read namelist
1189	READ ( 11, stg_par, ERR = 10, END = 20 )
1190
1191	!
1192	!-- Set flag that indicates that the synthetic turbulence generator is switched
1193	!-- on
1194	syn_turb_gen = .TRUE.
1195	GOTO 20
1196
1197	10 BACKSPACE( 11 )
1198	READ( 11 , '(A)') line
1199	CALL parin_fail_message( 'stg_par', line )
1200
1201	20 CONTINUE
1202
1203	END SUBROUTINE stg_parin
1204
1205
1206	!------------------------------------------------------------------------------!
1207	! Description:
1208	! ------------
1209	!> Read module-specific global restart data (Fortran binary format).
1210	!------------------------------------------------------------------------------!
1211	SUBROUTINE stg_rrd_global_ftn( found )
1212
1213	LOGICAL, INTENT(OUT) :: found !< flag indicating if variable was found
1214
1215	found = .TRUE.
1216
1217
1218	SELECT CASE ( restart_string(1:length) )
1219
1220	CASE ( 'time_stg_adjust' )
1221	READ ( 13 ) time_stg_adjust
1222
1223	CASE ( 'time_stg_call' )
1224	READ ( 13 ) time_stg_call
1225
1226	CASE ( 'use_syn_turb_gen' )
1227	READ ( 13 ) use_syn_turb_gen
1228
1229	CASE DEFAULT
1230
1231	found = .FALSE.
1232
1233	END SELECT
1234
1235
1236	END SUBROUTINE stg_rrd_global_ftn
1237
1238
1239	!------------------------------------------------------------------------------!
1240	! Description:
1241	! ------------
1242	!> Read module-specific global restart data (MPI-IO).
1243	!------------------------------------------------------------------------------!
1244	SUBROUTINE stg_rrd_global_mpi
1245
1246	CALL rrd_mpi_io( 'time_stg_adjust', time_stg_adjust )
1247	CALL rrd_mpi_io( 'time_stg_call', time_stg_call )
1248	CALL rrd_mpi_io( 'use_syn_turb_gen', use_syn_turb_gen )
1249
1250	END SUBROUTINE stg_rrd_global_mpi
1251
1252
1253	!------------------------------------------------------------------------------!
1254	! Description:
1255	! ------------
1256	!> This routine writes the respective restart data.
1257	!------------------------------------------------------------------------------!
1258	SUBROUTINE stg_wrd_global
1259
1260	IF ( TRIM( restart_data_format_output ) == 'fortran_binary' ) THEN
1261
1262	CALL wrd_write_string( 'time_stg_adjust' )
1263	WRITE ( 14 ) time_stg_adjust
1264
1265	CALL wrd_write_string( 'time_stg_call' )
1266	WRITE ( 14 ) time_stg_call
1267
1268	CALL wrd_write_string( 'use_syn_turb_gen' )
1269	WRITE ( 14 ) use_syn_turb_gen
1270
1271	ELSEIF ( TRIM( restart_data_format_output ) == 'mpi' ) THEN
1272
1273	CALL wrd_mpi_io( 'time_stg_adjust', time_stg_adjust )
1274	CALL wrd_mpi_io( 'time_stg_call', time_stg_call )
1275	CALL wrd_mpi_io( 'use_syn_turb_gen', use_syn_turb_gen )
1276
1277	ENDIF
1278
1279	END SUBROUTINE stg_wrd_global
1280
1281
1282	!------------------------------------------------------------------------------!
1283	! Description:
1284	! ------------
1285	!> Create turbulent inflow fields for u, v, w with prescribed length scales and
1286	!> Reynolds stress tensor after a method of Xie and Castro (2008), modified
1287	!> following suggestions of Kim et al. (2013), and using a Lund rotation
1288	!> (Lund, 1998).
1289	!------------------------------------------------------------------------------!
1290	SUBROUTINE stg_main
1291
1292	USE exchange_horiz_mod, &
1293	ONLY: exchange_horiz
1294
1295	INTEGER(iwp) :: i !< grid index in x-direction
1296	INTEGER(iwp) :: j !< loop index in y-direction
1297	INTEGER(iwp) :: k !< loop index in z-direction
1298
1299	LOGICAL :: stg_call = .FALSE. !< control flag indicating whether turbulence was updated or only restored from last call
1300
1301	REAL(wp) :: dt_stg !< wheighted subtimestep
1302
1303	REAL(wp), DIMENSION(3) :: mc_factor_l !< local mass flux correction factor
1304
1305	IF ( debug_output_timestep ) CALL debug_message( 'stg_main', 'start' )
1306	!
1307	!-- Calculate time step which is needed for filter functions
1308	dt_stg = MAX( dt_3d, dt_stg_call )
1309	!
1310	!-- Check if synthetic turbulence generator needs to be called and new
1311	!-- perturbations need to be created or if old disturbances can be imposed
1312	!-- again.
1313	IF ( time_stg_call >= dt_stg_call .AND. &
1314	intermediate_timestep_count == intermediate_timestep_count_max ) THEN
1315	stg_call = .TRUE.
1316	ELSE
1317	stg_call = .FALSE.
1318	ENDIF
1319	!
1320	!-- Initial value of fu, fv, fw
1321	IF ( time_since_reference_point == 0.0_wp .AND. .NOT. velocity_seed_initialized ) THEN
1322	!
1323	!-- Generate turbulence at the left and right boundary. Random numbers
1324	!-- for the yz-planes at the left/right boundary are generated by the
1325	!-- left-sided mpi ranks only. After random numbers are calculated, they
1326	!-- are distributed to all other mpi ranks in the model, so that the
1327	!-- velocity seed matrices are available on all mpi ranks (i.e. also on the
1328	!-- right-sided boundary mpi ranks). In case of offline nesting, this implies,
1329	!-- that the left- and the right-sided lateral boundary have the same initial
1330	!-- seeds.
1331	!-- Note, in case of inflow from the right only, only turbulence at the left
1332	!-- boundary is required.
1333	IF ( .NOT. ( nesting_offline .OR. &
1334	( child_domain .AND. rans_mode_parent &
1335	.AND. .NOT. rans_mode ) ) ) THEN
1336	CALL stg_generate_seed_yz( nuy, nuz, buy, buz, fu_yz, id_stg_left )
1337	CALL stg_generate_seed_yz( nvy, nvz, bvy, bvz, fv_yz, id_stg_left )
1338	CALL stg_generate_seed_yz( nwy, nwz, bwy, bwz, fw_yz, id_stg_left )
1339	ELSE
1340	CALL stg_generate_seed_yz( nuy, nuz, buy, buz, fu_yz, &
1341	id_stg_left, id_stg_right )
1342	CALL stg_generate_seed_yz( nvy, nvz, bvy, bvz, fv_yz, &
1343	id_stg_left, id_stg_right )
1344	CALL stg_generate_seed_yz( nwy, nwz, bwy, bwz, fw_yz, &
1345	id_stg_left, id_stg_right )
1346	!
1347	!-- Generate turbulence at the south and north boundary. Random numbers
1348	!-- for the xz-planes at the south/north boundary are generated by the
1349	!-- south-sided mpi ranks only. Please see also comment above.
1350	CALL stg_generate_seed_xz( nux, nuz, bux, buz, fu_xz, &
1351	id_stg_south, id_stg_north )
1352	CALL stg_generate_seed_xz( nvx, nvz, bvx, bvz, fv_xz, &
1353	id_stg_south, id_stg_north )
1354	CALL stg_generate_seed_xz( nwx, nwz, bwx, bwz, fw_xz, &
1355	id_stg_south, id_stg_north )
1356	ENDIF
1357	velocity_seed_initialized = .TRUE.
1358	ENDIF
1359	!
1360	!-- New set of fu, fv, fw. Note, for inflow from the left side only, velocity
1361	!-- seeds are only required at the left boundary, while in case of offline
1362	!-- nesting or RANS-LES nesting velocity seeds are required also at the
1363	!-- right, south and north boundaries.
1364	IF ( stg_call ) THEN
1365	IF ( .NOT. ( nesting_offline .OR. &
1366	( child_domain .AND. rans_mode_parent &
1367	.AND. .NOT. rans_mode ) ) ) THEN
1368	CALL stg_generate_seed_yz( nuy, nuz, buy, buz, fuo_yz, id_stg_left )
1369	CALL stg_generate_seed_yz( nvy, nvz, bvy, bvz, fvo_yz, id_stg_left )
1370	CALL stg_generate_seed_yz( nwy, nwz, bwy, bwz, fwo_yz, id_stg_left )
1371
1372	ELSE
1373	CALL stg_generate_seed_yz( nuy, nuz, buy, buz, fuo_yz, &
1374	id_stg_left, id_stg_right )
1375	CALL stg_generate_seed_yz( nvy, nvz, bvy, bvz, fvo_yz, &
1376	id_stg_left, id_stg_right )
1377	CALL stg_generate_seed_yz( nwy, nwz, bwy, bwz, fwo_yz, &
1378	id_stg_left, id_stg_right )
1379
1380	CALL stg_generate_seed_xz( nux, nuz, bux, buz, fuo_xz, &
1381	id_stg_south, id_stg_north )
1382	CALL stg_generate_seed_xz( nvx, nvz, bvx, bvz, fvo_xz, &
1383	id_stg_south, id_stg_north )
1384	CALL stg_generate_seed_xz( nwx, nwz, bwx, bwz, fwo_xz, &
1385	id_stg_south, id_stg_north )
1386	ENDIF
1387	ENDIF
1388
1389	!
1390	!-- Turbulence generation at left and/or right boundary
1391	IF ( myidx == id_stg_left .OR. myidx == id_stg_right ) THEN
1392	!
1393	!-- Calculate new set of perturbations. Do this only at last RK3-substep and
1394	!-- when dt_stg_call is exceeded. Else the old set of perturbations is
1395	!-- imposed
1396	IF ( stg_call ) THEN
1397
1398	DO j = nys, nyn
1399	DO k = nzb, nzt + 1
1400	!
1401	!-- Update fu, fv, fw following Eq. 14 of Xie and Castro (2008)
1402	IF ( tu(k) == 0.0_wp ) THEN
1403	fu_yz(k,j) = fuo_yz(k,j)
1404	ELSE
1405	fu_yz(k,j) = fu_yz(k,j) * EXP( -pi * dt_stg * 0.5_wp / tu(k) ) + &
1406	fuo_yz(k,j) * SQRT( 1.0_wp - EXP( -pi * dt_stg / tu(k) ) )
1407	ENDIF
1408
1409	IF ( tv(k) == 0.0_wp ) THEN
1410	fv_yz(k,j) = fvo_yz(k,j)
1411	ELSE
1412	fv_yz(k,j) = fv_yz(k,j) * EXP( -pi * dt_stg * 0.5_wp / tv(k) ) + &
1413	fvo_yz(k,j) * SQRT( 1.0_wp - EXP( -pi * dt_stg / tv(k) ) )
1414	ENDIF
1415
1416	IF ( tw(k) == 0.0_wp ) THEN
1417	fw_yz(k,j) = fwo_yz(k,j)
1418	ELSE
1419	fw_yz(k,j) = fw_yz(k,j) * EXP( -pi * dt_stg * 0.5_wp / tw(k) ) + &
1420	fwo_yz(k,j) * SQRT( 1.0_wp - EXP( -pi * dt_stg / tw(k) ) )
1421	ENDIF
1422	ENDDO
1423	ENDDO
1424
1425	dist_yz(nzb,:,1) = 0.0_wp
1426	dist_yz(nzb,:,2) = 0.0_wp
1427	dist_yz(nzb,:,3) = 0.0_wp
1428
1429	IF ( myidx == id_stg_left ) i = nxl
1430	IF ( myidx == id_stg_right ) i = nxr+1
1431	DO j = nys, nyn
1432	DO k = nzb+1, nzt + 1
1433	!
1434	!-- Lund rotation following Eq. 17 in Xie and Castro (2008).
1435	!-- Additional factors are added to improve the variance of v and w
1436	dist_yz(k,j,1) = MIN( a11(k) * fu_yz(k,j), 3.0_wp ) * &
1437	MERGE( 1.0_wp, 0.0_wp, &
1438	BTEST( wall_flags_total_0(k,j,i), 1 ) )
1439	ENDDO
1440	ENDDO
1441
1442	IF ( myidx == id_stg_left ) i = nxl-1
1443	IF ( myidx == id_stg_right ) i = nxr+1
1444	DO j = nys, nyn
1445	DO k = nzb+1, nzt + 1
1446	!
1447	!-- Lund rotation following Eq. 17 in Xie and Castro (2008).
1448	!-- Additional factors are added to improve the variance of v and w
1449	!-- experimental test of 1.2
1450	dist_yz(k,j,2) = MIN( ( SQRT( a22(k) / MAXVAL(a22) ) &
1451	* 1.2_wp ) &
1452	* ( a21(k) * fu_yz(k,j) &
1453	+ a22(k) * fv_yz(k,j) ), 3.0_wp ) * &
1454	MERGE( 1.0_wp, 0.0_wp, &
1455	BTEST( wall_flags_total_0(k,j,i), 2 ) )
1456	dist_yz(k,j,3) = MIN( ( SQRT(a33(k) / MAXVAL(a33) ) &
1457	* 1.3_wp ) &
1458	* ( a31(k) * fu_yz(k,j) &
1459	+ a32(k) * fv_yz(k,j) &
1460	+ a33(k) * fw_yz(k,j) ), 3.0_wp ) * &
1461	MERGE( 1.0_wp, 0.0_wp, &
1462	BTEST( wall_flags_total_0(k,j,i), 3 ) )
1463	ENDDO
1464	ENDDO
1465	ENDIF
1466	!
1467	!-- Mass flux correction following Kim et al. (2013)
1468	!-- This correction factor insures that the mass flux is preserved at the
1469	!-- inflow boundary. First, calculate mean value of the imposed
1470	!-- perturbations at yz boundary.
1471	!-- Note, this needs to be done only after the last RK3-substep, else
1472	!-- the boundary values won't be accessed.
1473	IF ( intermediate_timestep_count == intermediate_timestep_count_max ) THEN
1474	mc_factor_l = 0.0_wp
1475	mc_factor = 0.0_wp
1476	!
1477	!-- Sum up the original volume flows (with and without perturbations).
1478	!-- Note, for non-normal components (here v and w) it is actually no
1479	!-- volume flow.
1480	IF ( myidx == id_stg_left ) i = nxl
1481	IF ( myidx == id_stg_right ) i = nxr+1
1482
1483	mc_factor_l(1) = SUM( dist_yz(nzb:nzt,nys:nyn,1) &
1484	* MERGE( 1.0_wp, 0.0_wp, &
1485	BTEST( wall_flags_total_0(nzb:nzt,nys:nyn,i), 1 ) ) )
1486
1487	IF ( myidx == id_stg_left ) i = nxl-1
1488	IF ( myidx == id_stg_right ) i = nxr+1
1489
1490	mc_factor_l(2) = SUM( dist_yz(nzb:nzt,nysv:nyn,2) &
1491	* MERGE( 1.0_wp, 0.0_wp, &
1492	BTEST( wall_flags_total_0(nzb:nzt,nysv:nyn,i), 2 ) ) )
1493	mc_factor_l(3) = SUM( dist_yz(nzb:nzt,nys:nyn,3) &
1494	* MERGE( 1.0_wp, 0.0_wp, &
1495	BTEST( wall_flags_total_0(nzb:nzt,nys:nyn,i), 3 ) ) )
1496
1497	#if defined( __parallel )
1498	CALL MPI_ALLREDUCE( mc_factor_l, mc_factor, &
1499	3, MPI_REAL, MPI_SUM, comm1dy, ierr )
1500	#else
1501	mc_factor = mc_factor_l
1502	#endif
1503	!
1504	!-- Calculate correction factor and force zero mean perturbations.
1505	mc_factor = mc_factor / REAL( nr_non_topo_yz, KIND = wp )
1506
1507	IF ( myidx == id_stg_left ) i = nxl
1508	IF ( myidx == id_stg_right ) i = nxr+1
1509
1510	dist_yz(:,nys:nyn,1) = ( dist_yz(:,nys:nyn,1) - mc_factor(1) ) &
1511	* MERGE( 1.0_wp, 0.0_wp, &
1512	BTEST( wall_flags_total_0(:,nys:nyn,i), 1 ) )
1513
1514
1515	IF ( myidx == id_stg_left ) i = nxl-1
1516	IF ( myidx == id_stg_right ) i = nxr+1
1517
1518	dist_yz(:,nys:nyn,2) = ( dist_yz(:,nys:nyn,2) - mc_factor(2) ) &
1519	* MERGE( 1.0_wp, 0.0_wp, &
1520	BTEST( wall_flags_total_0(:,nys:nyn,i), 2 ) )
1521
1522	dist_yz(:,nys:nyn,3) = ( dist_yz(:,nys:nyn,3) - mc_factor(3) ) &
1523	* MERGE( 1.0_wp, 0.0_wp, &
1524	BTEST( wall_flags_total_0(:,nys:nyn,i), 3 ) )
1525	!
1526	!-- Add disturbances
1527	IF ( myidx == id_stg_left ) THEN
1528	!
1529	!-- For the left boundary distinguish between mesoscale offline / self
1530	!-- nesting and turbulent inflow at the left boundary only. In the latter
1531	!-- case turbulence is imposed on the mean inflow profiles.
1532	IF ( .NOT. nesting_offline .AND. .NOT. child_domain ) THEN
1533	!
1534	!-- Add disturbance at the inflow
1535	DO j = nys, nyn
1536	DO k = nzb, nzt+1
1537	u(k,j,-nbgp+1:0) = ( mean_inflow_profiles(k,1) + &
1538	dist_yz(k,j,1) ) &
1539	* MERGE( 1.0_wp, 0.0_wp, &
1540	BTEST( wall_flags_total_0(k,j,0), 1 ) )
1541	v(k,j,-nbgp:-1) = ( mean_inflow_profiles(k,2) + &
1542	dist_yz(k,j,2) ) &
1543	* MERGE( 1.0_wp, 0.0_wp, &
1544	BTEST( wall_flags_total_0(k,j,-1), 2 ) )
1545	w(k,j,-nbgp:-1) = dist_yz(k,j,3) &
1546	* MERGE( 1.0_wp, 0.0_wp, &
1547	BTEST( wall_flags_total_0(k,j,-1), 3 ) )
1548	ENDDO
1549	ENDDO
1550	ELSE
1551
1552	DO j = nys, nyn
1553	DO k = nzb+1, nzt
1554	u(k,j,0) = ( u(k,j,0) + dist_yz(k,j,1) ) &
1555	* MERGE( 1.0_wp, 0.0_wp, &
1556	BTEST( wall_flags_total_0(k,j,0), 1 ) )
1557	u(k,j,-1) = u(k,j,0)
1558	v(k,j,-1) = ( v(k,j,-1) + dist_yz(k,j,2) ) &
1559	* MERGE( 1.0_wp, 0.0_wp, &
1560	BTEST( wall_flags_total_0(k,j,-1), 2 ) )
1561	w(k,j,-1) = ( w(k,j,-1) + dist_yz(k,j,3) ) &
1562	* MERGE( 1.0_wp, 0.0_wp, &
1563	BTEST( wall_flags_total_0(k,j,-1), 3 ) )
1564	ENDDO
1565	ENDDO
1566	ENDIF
1567	ENDIF
1568	IF ( myidx == id_stg_right ) THEN
1569	DO j = nys, nyn
1570	DO k = nzb+1, nzt
1571	u(k,j,nxr+1) = ( u(k,j,nxr+1) + dist_yz(k,j,1) ) &
1572	* MERGE( 1.0_wp, 0.0_wp, &
1573	BTEST( wall_flags_total_0(k,j,nxr+1), 1 ) )
1574	v(k,j,nxr+1) = ( v(k,j,nxr+1) + dist_yz(k,j,2) ) &
1575	* MERGE( 1.0_wp, 0.0_wp, &
1576	BTEST( wall_flags_total_0(k,j,nxr+1), 2 ) )
1577	w(k,j,nxr+1) = ( w(k,j,nxr+1) + dist_yz(k,j,3) ) &
1578	* MERGE( 1.0_wp, 0.0_wp, &
1579	BTEST( wall_flags_total_0(k,j,nxr+1), 3 ) )
1580	ENDDO
1581	ENDDO
1582	ENDIF
1583	ENDIF
1584	ENDIF
1585	!
1586	!-- Turbulence generation at north and south boundary
1587	IF ( myidy == id_stg_north .OR. myidy == id_stg_south ) THEN
1588	!
1589	!-- Calculate new set of perturbations. Do this only at last RK3-substep and
1590	!-- when dt_stg_call is exceeded. Else the old set of perturbations is
1591	!-- imposed
1592	IF ( stg_call ) THEN
1593	DO i = nxl, nxr
1594	DO k = nzb, nzt + 1
1595	!
1596	!-- Update fu, fv, fw following Eq. 14 of Xie and Castro (2008)
1597	IF ( tu(k) == 0.0_wp ) THEN
1598	fu_xz(k,i) = fuo_xz(k,i)
1599	ELSE
1600	fu_xz(k,i) = fu_xz(k,i) * EXP( -pi * dt_stg * 0.5_wp / tu(k) ) + &
1601	fuo_xz(k,i) * SQRT( 1.0_wp - EXP( -pi * dt_stg / tu(k) ) )
1602	ENDIF
1603
1604	IF ( tv(k) == 0.0_wp ) THEN
1605	fv_xz(k,i) = fvo_xz(k,i)
1606	ELSE
1607	fv_xz(k,i) = fv_xz(k,i) * EXP( -pi * dt_stg * 0.5_wp / tv(k) ) + &
1608	fvo_xz(k,i) * SQRT( 1.0_wp - EXP( -pi * dt_stg / tv(k) ) )
1609	ENDIF
1610
1611	IF ( tw(k) == 0.0_wp ) THEN
1612	fw_xz(k,i) = fwo_xz(k,i)
1613	ELSE
1614	fw_xz(k,i) = fw_xz(k,i) * EXP( -pi * dt_stg * 0.5_wp / tw(k) ) + &
1615	fwo_xz(k,i) * SQRT( 1.0_wp - EXP( -pi * dt_stg / tw(k) ) )
1616	ENDIF
1617	ENDDO
1618	ENDDO
1619
1620
1621	dist_xz(nzb,:,1) = 0.0_wp
1622	dist_xz(nzb,:,2) = 0.0_wp
1623	dist_xz(nzb,:,3) = 0.0_wp
1624
1625	IF ( myidy == id_stg_south ) j = nys
1626	IF ( myidy == id_stg_north ) j = nyn+1
1627	DO i = nxl, nxr
1628	DO k = nzb+1, nzt + 1
1629	!
1630	!-- Lund rotation following Eq. 17 in Xie and Castro (2008).
1631	!-- Additional factors are added to improve the variance of v and w
1632	!experimental test of 1.2
1633	dist_xz(k,i,2) = MIN( ( SQRT( a22(k) / MAXVAL(a22) ) &
1634	* 1.2_wp ) &
1635	* ( a21(k) * fu_xz(k,i) &
1636	+ a22(k) * fv_xz(k,i) ), 3.0_wp ) * &
1637	MERGE( 1.0_wp, 0.0_wp, &
1638	BTEST( wall_flags_total_0(k,j,i), 2 ) )
1639	ENDDO
1640	ENDDO
1641
1642	IF ( myidy == id_stg_south ) j = nys-1
1643	IF ( myidy == id_stg_north ) j = nyn+1
1644	DO i = nxl, nxr
1645	DO k = nzb+1, nzt + 1
1646	!
1647	!-- Lund rotation following Eq. 17 in Xie and Castro (2008).
1648	!-- Additional factors are added to improve the variance of v and w
1649	dist_xz(k,i,1) = MIN( a11(k) * fu_xz(k,i), 3.0_wp ) * &
1650	MERGE( 1.0_wp, 0.0_wp, &
1651	BTEST( wall_flags_total_0(k,j,i), 1 ) )
1652
1653	dist_xz(k,i,3) = MIN( ( SQRT(a33(k) / MAXVAL(a33) ) &
1654	* 1.3_wp ) &
1655	* ( a31(k) * fu_xz(k,i) &
1656	+ a32(k) * fv_xz(k,i) &
1657	+ a33(k) * fw_xz(k,i) ), 3.0_wp ) * &
1658	MERGE( 1.0_wp, 0.0_wp, &
1659	BTEST( wall_flags_total_0(k,j,i), 3 ) )
1660	ENDDO
1661	ENDDO
1662	ENDIF
1663
1664	!
1665	!-- Mass flux correction following Kim et al. (2013)
1666	!-- This correction factor insures that the mass flux is preserved at the
1667	!-- inflow boundary. First, calculate mean value of the imposed
1668	!-- perturbations at yz boundary.
1669	!-- Note, this needs to be done only after the last RK3-substep, else
1670	!-- the boundary values won't be accessed.
1671	IF ( intermediate_timestep_count == intermediate_timestep_count_max ) THEN
1672	mc_factor_l = 0.0_wp
1673	mc_factor = 0.0_wp
1674
1675	IF ( myidy == id_stg_south ) j = nys
1676	IF ( myidy == id_stg_north ) j = nyn+1
1677
1678	mc_factor_l(2) = SUM( dist_xz(nzb:nzt,nxl:nxr,2) &
1679	* MERGE( 1.0_wp, 0.0_wp, &
1680	BTEST( wall_flags_total_0(nzb:nzt,j,nxl:nxr), 2 ) ) )
1681
1682	IF ( myidy == id_stg_south ) j = nys-1
1683	IF ( myidy == id_stg_north ) j = nyn+1
1684
1685	mc_factor_l(1) = SUM( dist_xz(nzb:nzt,nxlu:nxr,1) &
1686	* MERGE( 1.0_wp, 0.0_wp, &
1687	BTEST( wall_flags_total_0(nzb:nzt,j,nxlu:nxr), 1 ) ) )
1688	mc_factor_l(3) = SUM( dist_xz(nzb:nzt,nxl:nxr,3) &
1689	* MERGE( 1.0_wp, 0.0_wp, &
1690	BTEST( wall_flags_total_0(nzb:nzt,j,nxl:nxr), 3 ) ) )
1691
1692	#if defined( __parallel )
1693	CALL MPI_ALLREDUCE( mc_factor_l, mc_factor, &
1694	3, MPI_REAL, MPI_SUM, comm1dx, ierr )
1695	#else
1696	mc_factor = mc_factor_l
1697	#endif
1698
1699	mc_factor = mc_factor / REAL( nr_non_topo_xz, KIND = wp )
1700
1701	IF ( myidy == id_stg_south ) j = nys
1702	IF ( myidy == id_stg_north ) j = nyn+1
1703
1704	dist_xz(:,nxl:nxr,2) = ( dist_xz(:,nxl:nxr,2) - mc_factor(2) ) &
1705	* MERGE( 1.0_wp, 0.0_wp, &
1706	BTEST( wall_flags_total_0(:,j,nxl:nxr), 2 ) )
1707
1708
1709	IF ( myidy == id_stg_south ) j = nys-1
1710	IF ( myidy == id_stg_north ) j = nyn+1
1711
1712	dist_xz(:,nxl:nxr,1) = ( dist_xz(:,nxl:nxr,1) - mc_factor(1) ) &
1713	* MERGE( 1.0_wp, 0.0_wp, &
1714	BTEST( wall_flags_total_0(:,j,nxl:nxr), 1 ) )
1715
1716	dist_xz(:,nxl:nxr,3) = ( dist_xz(:,nxl:nxr,3) - mc_factor(3) ) &
1717	* MERGE( 1.0_wp, 0.0_wp, &
1718	BTEST( wall_flags_total_0(:,j,nxl:nxr), 3 ) )
1719	!
1720	!-- Add disturbances
1721	IF ( myidy == id_stg_south ) THEN
1722	DO i = nxl, nxr
1723	DO k = nzb+1, nzt
1724	u(k,-1,i) = ( u(k,-1,i) + dist_xz(k,i,1) ) &
1725	* MERGE( 1.0_wp, 0.0_wp, &
1726	BTEST( wall_flags_total_0(k,-1,i), 1 ) )
1727	v(k,0,i) = ( v(k,0,i) + dist_xz(k,i,2) ) &
1728	* MERGE( 1.0_wp, 0.0_wp, &
1729	BTEST( wall_flags_total_0(k,0,i), 2 ) )
1730	v(k,-1,i) = v(k,0,i)
1731	w(k,-1,i) = ( w(k,-1,i) + dist_xz(k,i,3) ) &
1732	* MERGE( 1.0_wp, 0.0_wp, &
1733	BTEST( wall_flags_total_0(k,-1,i), 3 ) )
1734	ENDDO
1735	ENDDO
1736	ENDIF
1737	IF ( myidy == id_stg_north ) THEN
1738
1739	DO i = nxl, nxr
1740	DO k = nzb+1, nzt
1741	u(k,nyn+1,i) = ( u(k,nyn+1,i) + dist_xz(k,i,1) ) &
1742	* MERGE( 1.0_wp, 0.0_wp, &
1743	BTEST( wall_flags_total_0(k,nyn+1,i), 1 ) )
1744	v(k,nyn+1,i) = ( v(k,nyn+1,i) + dist_xz(k,i,2) ) &
1745	* MERGE( 1.0_wp, 0.0_wp, &
1746	BTEST( wall_flags_total_0(k,nyn+1,i), 2 ) )
1747	w(k,nyn+1,i) = ( w(k,nyn+1,i) + dist_xz(k,i,3) ) &
1748	* MERGE( 1.0_wp, 0.0_wp, &
1749	BTEST( wall_flags_total_0(k,nyn+1,i), 3 ) )
1750	ENDDO
1751	ENDDO
1752	ENDIF
1753	ENDIF
1754	ENDIF
1755	!
1756	!-- Exchange ghost points.
1757	CALL exchange_horiz( u, nbgp )
1758	CALL exchange_horiz( v, nbgp )
1759	CALL exchange_horiz( w, nbgp )
1760	!
1761	!-- Finally, set time counter for calling STG to zero
1762	IF ( stg_call ) time_stg_call = 0.0_wp
1763
1764	IF ( debug_output_timestep ) CALL debug_message( 'stg_main', 'end' )
1765
1766	END SUBROUTINE stg_main
1767
1768	!------------------------------------------------------------------------------!
1769	! Description:
1770	! ------------
1771	!> Generate a set of random number rand_it wich is equal on each PE
1772	!> and calculate the velocity seed f_n.
1773	!> f_n is splitted in vertical direction by the number of PEs in x-direction and
1774	!> and each PE calculates a vertical subsection of f_n. At the the end, all
1775	!> parts are collected to form the full array.
1776	!------------------------------------------------------------------------------!
1777	SUBROUTINE stg_generate_seed_yz( n_y, n_z, b_y, b_z, f_n, id_left, id_right )
1778
1779	INTEGER(iwp) :: id_left !< core ids at respective boundaries
1780	INTEGER(iwp), OPTIONAL :: id_right !< core ids at respective boundaries
1781	INTEGER(iwp) :: j !< loop index in y-direction
1782	INTEGER(iwp) :: jj !< loop index in y-direction
1783	INTEGER(iwp) :: k !< loop index in z-direction
1784	INTEGER(iwp) :: kk !< loop index in z-direction
1785	INTEGER(iwp) :: send_count !< send count for MPI_GATHERV
1786
1787	INTEGER(iwp), DIMENSION(nzb:nzt+1) :: n_y !< length scale in y-direction
1788	INTEGER(iwp), DIMENSION(nzb:nzt+1) :: n_z !< length scale in z-direction
1789
1790	REAL(wp) :: nyz_inv !< inverse of number of grid points in yz-slice
1791	REAL(wp) :: rand_av !< average of random number
1792	REAL(wp) :: rand_sigma_inv !< inverse of stdev of random number
1793
1794	REAL(wp), DIMENSION(-mergp:mergp,nzb:nzt+1) :: b_y !< filter function in y-direction
1795	REAL(wp), DIMENSION(-mergp:mergp,nzb:nzt+1) :: b_z !< filter function in z-direction
1796
1797	REAL(wp), DIMENSION(nzb_x_stg:nzt_x_stg+1,nys:nyn) :: f_n_l !< local velocity seed
1798	REAL(wp), DIMENSION(nzb:nzt+1,nys:nyn) :: f_n !< velocity seed
1799
1800	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: rand_it !< global array of random numbers
1801	!
1802	!-- Generate random numbers using the parallel random generator.
1803	!-- The set of random numbers are modified to have an average of 0 and
1804	!-- unit variance. Note, at the end the random number array must be defined
1805	!-- globally in order to compute the correlation matrices. However,
1806	!-- the calculation and normalization of random numbers is done locally,
1807	!-- while the result is later distributed to all processes. Further,
1808	!-- please note, a set of random numbers is only calculated for the
1809	!-- left boundary, while the right boundary uses the same random numbers
1810	!-- and thus also computes the same correlation matrix.
1811	ALLOCATE( rand_it(nzb-mergp:nzt+1+mergp,-mergp+nys:nyn+mergp) )
1812	rand_it = 0.0_wp
1813
1814	rand_av = 0.0_wp
1815	rand_sigma_inv = 0.0_wp
1816	nyz_inv = 1.0_wp / REAL( ( nzt + 1 + mergp - ( nzb - mergp ) + 1 ) &
1817	* ( ny + mergp - ( 0 - mergp ) + 1 ), &
1818	KIND=wp )
1819	!
1820	!-- Compute and normalize random numbers.
1821	DO j = nys - mergp, nyn + mergp
1822	!
1823	!-- Put the random seeds at grid point j
1824	CALL random_seed_parallel( put=seq_rand_yz(:,j) )
1825	DO k = nzb - mergp, nzt + 1 + mergp
1826	CALL random_number_parallel( random_dummy )
1827	rand_it(k,j) = random_dummy
1828	ENDDO
1829	!
1830	!-- Get the new random seeds from last call at grid point j
1831	CALL random_seed_parallel( get=seq_rand_yz(:,j) )
1832	ENDDO
1833	!
1834	!-- For normalization to zero mean, sum-up the global random numers.
1835	!-- To normalize the global set of random numbers,
1836	!-- the inner ghost layers mergp must not be summed-up, else
1837	!-- the random numbers on the ghost layers will be stronger weighted as they
1838	!-- also occur on the inner subdomains.
1839	DO j = MERGE( nys, nys - mergp, nys /= 0 ), &
1840	MERGE( nyn, nyn + mergp, nyn /= ny )
1841	DO k = nzb - mergp, nzt + 1 + mergp
1842	rand_av = rand_av + rand_it(k,j)
1843	ENDDO
1844	ENDDO
1845
1846	#if defined( __parallel )
1847	!
1848	!-- Sum-up the local averages of the random numbers
1849	CALL MPI_ALLREDUCE( MPI_IN_PLACE, rand_av, 1, MPI_REAL, &
1850	MPI_SUM, comm1dy, ierr )
1851	#endif
1852	rand_av = rand_av * nyz_inv
1853	!
1854	!-- Obtain zero mean
1855	rand_it= rand_it - rand_av
1856	!
1857	!-- Now, compute the variance
1858	DO j = MERGE( nys, nys - mergp, nys /= 0 ), &
1859	MERGE( nyn, nyn + mergp, nyn /= ny )
1860	DO k = nzb - mergp, nzt + 1 + mergp
1861	rand_sigma_inv = rand_sigma_inv + rand_it(k,j)**2
1862	ENDDO
1863	ENDDO
1864
1865	#if defined( __parallel )
1866	!
1867	!-- Sum-up the local quadratic averages of the random numbers
1868	CALL MPI_ALLREDUCE( MPI_IN_PLACE, rand_sigma_inv, 1, MPI_REAL, &
1869	MPI_SUM, comm1dy, ierr )
1870	#endif
1871	!
1872	!-- Compute standard deviation
1873	IF ( rand_sigma_inv /= 0.0_wp ) THEN
1874	rand_sigma_inv = 1.0_wp / SQRT( rand_sigma_inv * nyz_inv )
1875	ELSE
1876	rand_sigma_inv = 1.0_wp
1877	ENDIF
1878	!
1879	!-- Normalize with standard deviation to obtain unit variance
1880	rand_it = rand_it * rand_sigma_inv
1881
1882	CALL cpu_log( log_point_s(31), 'STG f_n factors', 'start' )
1883	!
1884	!-- Generate velocity seed following Eq.6 of Xie and Castro (2008). There
1885	!-- are two options. In the first one, the computation of the seeds is
1886	!-- distributed to all processes along the communicator comm1dy and
1887	!-- gathered on the leftmost and, if necessary, on the rightmost process.
1888	!-- For huge length scales the computational effort can become quite huge
1889	!-- (it scales with the turbulent length scales), so that gain by parallelization
1890	!-- exceeds the costs by the subsequent communication.
1891	!-- In the second option, which performs better when the turbulent length scales
1892	!-- are parametrized and thus the loops are smaller, the seeds are computed
1893	!-- locally and no communication is necessary.
1894	IF ( compute_velocity_seeds_local ) THEN
1895
1896	f_n = 0.0_wp
1897	DO j = nys, nyn
1898	DO k = nzb, nzt+1
1899	DO jj = -n_y(k), n_y(k)
1900	DO kk = -n_z(k), n_z(k)
1901	f_n(k,j) = f_n(k,j) + b_y(jj,k) * b_z(kk,k) * rand_it(k+kk,j+jj)
1902	ENDDO
1903	ENDDO
1904	ENDDO
1905	ENDDO
1906
1907	ELSE
1908
1909	f_n_l = 0.0_wp
1910	DO j = nys, nyn
1911	DO k = nzb_x_stg, nzt_x_stg+1
1912	DO jj = -n_y(k), n_y(k)
1913	DO kk = -n_z(k), n_z(k)
1914	f_n_l(k,j) = f_n_l(k,j) + b_y(jj,k) * b_z(kk,k) * rand_it(k+kk,j+jj)
1915	ENDDO
1916	ENDDO
1917	ENDDO
1918	ENDDO
1919	!
1920	!-- Gather velocity seeds of full subdomain
1921	send_count = nzt_x_stg - nzb_x_stg + 1
1922	IF ( nzt_x_stg == nzt ) send_count = send_count + 1
1923
1924	#if defined( __parallel )
1925	!
1926	!-- Gather the velocity seed matrix on left boundary mpi ranks.
1927	CALL MPI_GATHERV( f_n_l(nzb_x_stg,nys), send_count, stg_type_yz_small, &
1928	f_n(nzb+1,nys), recv_count_yz, displs_yz, stg_type_yz,&
1929	id_left, comm1dx, ierr )
1930	!
1931	!-- If required, gather the same velocity seed matrix on right boundary
1932	!-- mpi ranks (in offline nesting for example).
1933	IF ( PRESENT( id_right ) ) THEN
1934	CALL MPI_GATHERV( f_n_l(nzb_x_stg,nys), send_count, stg_type_yz_small, &
1935	f_n(nzb+1,nys), recv_count_yz, displs_yz, stg_type_yz,&
1936	id_right, comm1dx, ierr )
1937	ENDIF
1938	#else
1939	f_n(nzb+1:nzt+1,nys:nyn) = f_n_l(nzb_x_stg:nzt_x_stg+1,nys:nyn)
1940	!
1941	!-- Next line required to avoid compile errors because of unused dummy arguments
1942	IF ( id_left == 0 ) id_right = 0
1943	#endif
1944
1945	ENDIF
1946
1947	DEALLOCATE( rand_it )
1948
1949	CALL cpu_log( log_point_s(31), 'STG f_n factors', 'stop' )
1950
1951	END SUBROUTINE stg_generate_seed_yz
1952
1953
1954	!------------------------------------------------------------------------------!
1955	! Description:
1956	! ------------
1957	!> Generate a set of random number rand_it wich is equal on each PE
1958	!> and calculate the velocity seed f_n.
1959	!> f_n is splitted in vertical direction by the number of PEs in y-direction and
1960	!> and each PE calculates a vertical subsection of f_n. At the the end, all
1961	!> parts are collected to form the full array.
1962	!------------------------------------------------------------------------------!
1963	SUBROUTINE stg_generate_seed_xz( n_x, n_z, b_x, b_z, f_n, id_south, id_north )
1964
1965	INTEGER(iwp) :: i !< loop index in x-direction
1966	INTEGER(iwp) :: id_north !< core ids at respective boundaries
1967	INTEGER(iwp) :: id_south !< core ids at respective boundaries
1968	INTEGER(iwp) :: ii !< loop index in x-direction
1969	INTEGER(iwp) :: k !< loop index in z-direction
1970	INTEGER(iwp) :: kk !< loop index in z-direction
1971	INTEGER(iwp) :: send_count !< send count for MPI_GATHERV
1972
1973	INTEGER(iwp), DIMENSION(nzb:nzt+1) :: n_x !< length scale in x-direction
1974	INTEGER(iwp), DIMENSION(nzb:nzt+1) :: n_z !< length scale in z-direction
1975
1976	REAL(wp) :: nxz_inv !< inverse of number of grid points in xz-slice
1977	REAL(wp) :: rand_av !< average of random number
1978	REAL(wp) :: rand_sigma_inv !< inverse of stdev of random number
1979
1980	REAL(wp), DIMENSION(-mergp:mergp,nzb:nzt+1) :: b_x !< filter function in x-direction
1981	REAL(wp), DIMENSION(-mergp:mergp,nzb:nzt+1) :: b_z !< filter function in z-direction
1982
1983	REAL(wp), DIMENSION(nzb_y_stg:nzt_y_stg+1,nxl:nxr) :: f_n_l !< local velocity seed
1984	REAL(wp), DIMENSION(nzb:nzt+1,nxl:nxr) :: f_n !< velocity seed
1985
1986	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: rand_it !< global array of random numbers
1987
1988	!
1989	!-- Generate random numbers using the parallel random generator.
1990	!-- The set of random numbers are modified to have an average of 0 and
1991	!-- unit variance. Note, at the end the random number array must be defined
1992	!-- globally in order to compute the correlation matrices. However,
1993	!-- the calculation and normalization of random numbers is done locally,
1994	!-- while the result is later distributed to all processes. Further,
1995	!-- please note, a set of random numbers is only calculated for the
1996	!-- left boundary, while the right boundary uses the same random numbers
1997	!-- and thus also computes the same correlation matrix.
1998	ALLOCATE( rand_it(nzb-mergp:nzt+1+mergp,-mergp+nxl:nxr+mergp) )
1999	rand_it = 0.0_wp
2000
2001	rand_av = 0.0_wp
2002	rand_sigma_inv = 0.0_wp
2003	nxz_inv = 1.0_wp / REAL( ( nzt + 1 + mergp - ( nzb - mergp ) + 1 ) &
2004	* ( nx + mergp - ( 0 - mergp ) +1 ), &
2005	KIND=wp )
2006	!
2007	!-- Compute and normalize random numbers.
2008	DO i = nxl - mergp, nxr + mergp
2009	!
2010	!-- Put the random seeds at grid point ii
2011	CALL random_seed_parallel( put=seq_rand_xz(:,i) )
2012	DO k = nzb - mergp, nzt + 1 + mergp
2013	CALL random_number_parallel( random_dummy )
2014	rand_it(k,i) = random_dummy
2015	ENDDO
2016	!
2017	!-- Get the new random seeds from last call at grid point ii
2018	CALL random_seed_parallel( get=seq_rand_xz(:,i) )
2019	ENDDO
2020	!
2021	!-- For normalization to zero mean, sum-up the global random numers.
2022	!-- To normalize the global set of random numbers,
2023	!-- the inner ghost layers mergp must not be summed-up, else
2024	!-- the random numbers on the ghost layers will be stronger weighted as they
2025	!-- also occur on the inner subdomains.
2026	DO i = MERGE( nxl, nxl - mergp, nxl /= 0 ), &
2027	MERGE( nxr, nxr + mergp, nxr /= nx )
2028	DO k = nzb - mergp, nzt + 1 + mergp
2029	rand_av = rand_av + rand_it(k,i)
2030	ENDDO
2031	ENDDO
2032
2033	#if defined( __parallel )
2034	!
2035	!-- Sum-up the local averages of the random numbers
2036	CALL MPI_ALLREDUCE( MPI_IN_PLACE, rand_av, 1, MPI_REAL, &
2037	MPI_SUM, comm1dx, ierr )
2038	#endif
2039	rand_av = rand_av * nxz_inv
2040	!
2041	!-- Obtain zero mean
2042	rand_it= rand_it - rand_av
2043	!
2044	!-- Now, compute the variance
2045	DO i = MERGE( nxl, nxl - mergp, nxl /= 0 ), &
2046	MERGE( nxr, nxr + mergp, nxr /= nx )
2047	DO k = nzb - mergp, nzt + 1 + mergp
2048	rand_sigma_inv = rand_sigma_inv + rand_it(k,i)**2
2049	ENDDO
2050	ENDDO
2051
2052	#if defined( __parallel )
2053	!
2054	!-- Sum-up the local quadratic averages of the random numbers
2055	CALL MPI_ALLREDUCE( MPI_IN_PLACE, rand_sigma_inv, 1, MPI_REAL, &
2056	MPI_SUM, comm1dx, ierr )
2057	#endif
2058	!
2059	!-- Compute standard deviation
2060	IF ( rand_sigma_inv /= 0.0_wp ) THEN
2061	rand_sigma_inv = 1.0_wp / SQRT( rand_sigma_inv * nxz_inv )
2062	ELSE
2063	rand_sigma_inv = 1.0_wp
2064	ENDIF
2065	!
2066	!-- Normalize with standard deviation to obtain unit variance
2067	rand_it = rand_it * rand_sigma_inv
2068
2069	CALL cpu_log( log_point_s(31), 'STG f_n factors', 'start' )
2070	!
2071	!-- Generate velocity seed following Eq.6 of Xie and Castro (2008). There
2072	!-- are two options. In the first one, the computation of the seeds is
2073	!-- distributed to all processes along the communicator comm1dx and
2074	!-- gathered on the southmost and, if necessary, on the northmost process.
2075	!-- For huge length scales the computational effort can become quite huge
2076	!-- (it scales with the turbulent length scales), so that gain by parallelization
2077	!-- exceeds the costs by the subsequent communication.
2078	!-- In the second option, which performs better when the turbulent length scales
2079	!-- are parametrized and thus the loops are smaller, the seeds are computed
2080	!-- locally and no communication is necessary.
2081	IF ( compute_velocity_seeds_local ) THEN
2082
2083	f_n = 0.0_wp
2084	DO i = nxl, nxr
2085	DO k = nzb, nzt+1
2086	DO ii = -n_x(k), n_x(k)
2087	DO kk = -n_z(k), n_z(k)
2088	f_n(k,i) = f_n(k,i) + b_x(ii,k) * b_z(kk,k) * rand_it(k+kk,i+ii)
2089	ENDDO
2090	ENDDO
2091	ENDDO
2092	ENDDO
2093
2094	ELSE
2095
2096	f_n_l = 0.0_wp
2097	DO i = nxl, nxr
2098	DO k = nzb_y_stg, nzt_y_stg+1
2099	DO ii = -n_x(k), n_x(k)
2100	DO kk = -n_z(k), n_z(k)
2101	f_n_l(k,i) = f_n_l(k,i) + b_x(ii,k) * b_z(kk,k) * rand_it(k+kk,i+ii)
2102	ENDDO
2103	ENDDO
2104	ENDDO
2105	ENDDO
2106	!
2107	!-- Gather velocity seeds of full subdomain
2108	send_count = nzt_y_stg - nzb_y_stg + 1
2109	IF ( nzt_y_stg == nzt ) send_count = send_count + 1
2110
2111	#if defined( __parallel )
2112	!
2113	!-- Gather the processed velocity seed on south boundary mpi ranks.
2114	CALL MPI_GATHERV( f_n_l(nzb_y_stg,nxl), send_count, stg_type_xz_small, &
2115	f_n(nzb+1,nxl), recv_count_xz, displs_xz, stg_type_xz, &
2116	id_south, comm1dy, ierr )
2117	!
2118	!-- Gather the processed velocity seed on north boundary mpi ranks.
2119	CALL MPI_GATHERV( f_n_l(nzb_y_stg,nxl), send_count, stg_type_xz_small, &
2120	f_n(nzb+1,nxl), recv_count_xz, displs_xz, stg_type_xz, &
2121	id_north, comm1dy, ierr )
2122	#else
2123	f_n(nzb+1:nzt+1,nxl:nxr) = f_n_l(nzb_y_stg:nzt_y_stg+1,nxl:nxr)
2124	!
2125	!-- Next line required to avoid compile errors because of unused dummy arguments
2126	IF ( id_north == 0 ) id_south = 0
2127	#endif
2128
2129	ENDIF
2130
2131	DEALLOCATE( rand_it )
2132
2133	CALL cpu_log( log_point_s(31), 'STG f_n factors', 'stop' )
2134
2135	END SUBROUTINE stg_generate_seed_xz
2136
2137	!------------------------------------------------------------------------------!
2138	! Description:
2139	! ------------
2140	!> Parametrization of the Reynolds stress tensor, following the parametrization
2141	!> described in Rotach et al. (1996), which is applied in state-of-the-art
2142	!> dispserion modelling. Please note, the parametrization does not distinguish
2143	!> between along-wind and cross-wind turbulence.
2144	!------------------------------------------------------------------------------!
2145	SUBROUTINE parametrize_reynolds_stress
2146
2147	INTEGER(iwp) :: k !< loop index in z-direction
2148
2149	REAL(wp) :: zzi !< ratio of z/zi
2150
2151	DO k = nzb+1, nzt+1
2152	!
2153	!-- Calculate function to gradually decrease Reynolds stress above ABL top.
2154	!-- The function decreases to 1/10 after one length scale above the
2155	!-- ABL top.
2156	blend = MIN( 1.0_wp, EXP( d_l * zu(k) - d_l * zi_ribulk ) )
2157	!
2158	!-- Determine normalized height coordinate
2159	zzi = zu(k) / zi_ribulk
2160	!
2161	!-- u'u' and v'v'. Assume isotropy. Note, add a small negative number
2162	!-- to the denominator, else the mergpe-function can crash if scale_l is
2163	!-- zero.
2164	r11(k) = scale_us*2 ( &
2165	MERGE( 0.35_wp * ABS( &
2166	- zi_ribulk / ( kappa * scale_l - 10E-4_wp ) &
2167	)**( 2.0_wp / 3.0_wp ), &
2168	0.0_wp, &
2169	scale_l < 0.0_wp ) &
2170	+ 5.0_wp - 4.0_wp * zzi &
2171	) * blend
2172
2173	r22(k) = r11(k)
2174	!
2175	!-- w'w'
2176	r33(k) = scale_wm*2 ( &
2177	1.5_wp * zzi*( 2.0_wp / 3.0_wp ) EXP( -2.0_wp * zzi ) &
2178	+ ( 1.7_wp - zzi ) * ( scale_us / scale_wm )**2 &
2179	) * blend
2180	!
2181	!-- u'w' and v'w'. Assume isotropy.
2182	r31(k) = - scale_us*2 ( 1.01_wp - MIN( zzi, 1.0_wp ) ) * blend
2183	r32(k) = r31(k)
2184	!
2185	!-- For u'v' no parametrization exist so far - ?. For simplicity assume
2186	!-- a similar profile as for u'w'.
2187	r21(k) = r31(k)
2188	ENDDO
2189
2190	!
2191	!-- Set bottom boundary condition
2192	r11(nzb) = r11(nzb+1)
2193	r22(nzb) = r22(nzb+1)
2194	r33(nzb) = r33(nzb+1)
2195
2196	r21(nzb) = r11(nzb+1)
2197	r31(nzb) = r31(nzb+1)
2198	r32(nzb) = r32(nzb+1)
2199
2200
2201	END SUBROUTINE parametrize_reynolds_stress
2202
2203	!------------------------------------------------------------------------------!
2204	! Description:
2205	! ------------
2206	!> Calculate the coefficient matrix from the Lund rotation.
2207	!------------------------------------------------------------------------------!
2208	SUBROUTINE calc_coeff_matrix
2209
2210	INTEGER(iwp) :: k !< loop index in z-direction
2211
2212	!
2213	!-- Calculate coefficient matrix. Split loops to allow for loop vectorization.
2214	DO k = nzb+1, nzt+1
2215	IF ( r11(k) > 10E-6_wp ) THEN
2216	a11(k) = SQRT( r11(k) )
2217	a21(k) = r21(k) / a11(k)
2218	a31(k) = r31(k) / a11(k)
2219	ELSE
2220	a11(k) = 10E-8_wp
2221	a21(k) = 10E-8_wp
2222	a31(k) = 10E-8_wp
2223	ENDIF
2224	ENDDO
2225	DO k = nzb+1, nzt+1
2226	a22(k) = r22(k) - a21(k)**2
2227	IF ( a22(k) > 10E-6_wp ) THEN
2228	a22(k) = SQRT( a22(k) )
2229	a32(k) = r32(k) - a21(k) * a31(k) / a22(k)
2230	ELSE
2231	a22(k) = 10E-8_wp
2232	a32(k) = 10E-8_wp
2233	ENDIF
2234	ENDDO
2235	DO k = nzb+1, nzt+1
2236	a33(k) = r33(k) - a31(k)2 - a32(k)2
2237	IF ( a33(k) > 10E-6_wp ) THEN
2238	a33(k) = SQRT( a33(k) )
2239	ELSE
2240	a33(k) = 10E-8_wp
2241	ENDIF
2242	ENDDO
2243	!
2244	!-- Set bottom boundary condition
2245	a11(nzb) = a11(nzb+1)
2246	a22(nzb) = a22(nzb+1)
2247	a21(nzb) = a21(nzb+1)
2248	a33(nzb) = a33(nzb+1)
2249	a31(nzb) = a31(nzb+1)
2250	a32(nzb) = a32(nzb+1)
2251
2252	END SUBROUTINE calc_coeff_matrix
2253
2254	!------------------------------------------------------------------------------!
2255	! Description:
2256	! ------------
2257	!> This routine controls the re-adjustment of the turbulence statistics used
2258	!> for generating turbulence at the lateral boundaries.
2259	!------------------------------------------------------------------------------!
2260	SUBROUTINE stg_adjust
2261
2262	IF ( debug_output_timestep ) CALL debug_message( 'stg_adjust', 'start' )
2263	!
2264	!-- In case of dirichlet inflow boundary conditions only at one lateral
2265	!-- boundary, i.e. in the case no offline or self nesting is applied but
2266	!-- synthetic turbulence shall be parametrized nevertheless, the
2267	!-- boundary-layer depth need to determined first.
2268	IF ( .NOT. nesting_offline .AND. .NOT. child_domain ) &
2269	CALL nesting_offl_calc_zi
2270	!
2271	!-- Compute scaling parameters (domain-averaged), such as friction velocity
2272	!-- are calculated.
2273	CALL calc_scaling_variables
2274	!
2275	!-- Set length and time scales depending on boundary-layer height
2276	CALL calc_length_and_time_scale
2277	!
2278	!-- Parametrize Reynolds-stress tensor, diagonal elements as well
2279	!-- as r21 (v'u'), r31 (w'u'), r32 (w'v'). Parametrization follows
2280	!-- Rotach et al. (1996) and is based on boundary-layer depth,
2281	!-- friction velocity and velocity scale.
2282	CALL parametrize_reynolds_stress
2283	!
2284	!-- Calculate coefficient matrix from Reynolds stress tensor
2285	!-- (Lund rotation)
2286	CALL calc_coeff_matrix
2287	!
2288	!-- Determine filter functions on basis of updated length scales
2289	CALL stg_filter_func( nux, bux ) !filter ux
2290	CALL stg_filter_func( nuy, buy ) !filter uy
2291	CALL stg_filter_func( nuz, buz ) !filter uz
2292	CALL stg_filter_func( nvx, bvx ) !filter vx
2293	CALL stg_filter_func( nvy, bvy ) !filter vy
2294	CALL stg_filter_func( nvz, bvz ) !filter vz
2295	CALL stg_filter_func( nwx, bwx ) !filter wx
2296	CALL stg_filter_func( nwy, bwy ) !filter wy
2297	CALL stg_filter_func( nwz, bwz ) !filter wz
2298	!
2299	!-- Reset time counter for controlling next adjustment to zero
2300	time_stg_adjust = 0.0_wp
2301
2302	IF ( debug_output_timestep ) CALL debug_message( 'stg_adjust', 'end' )
2303
2304	END SUBROUTINE stg_adjust
2305
2306
2307	!------------------------------------------------------------------------------!
2308	! Description:
2309	! ------------
2310	!> Calculates turbuluent length and time scales if these are not available
2311	!> from measurements.
2312	!------------------------------------------------------------------------------!
2313	SUBROUTINE calc_length_and_time_scale
2314
2315	INTEGER(iwp) :: k !< loop index in z-direction
2316
2317	REAL(wp) :: length_scale_dum !< effectively used length scale
2318
2319	!
2320	!-- In initial call the boundary-layer depth can be zero. This case, set
2321	!-- minimum value for boundary-layer depth, to setup length scales correctly.
2322	zi_ribulk = MAX( zi_ribulk, zw(nzb+2) )
2323	!
2324	!-- Set-up default turbulent length scales. From the numerical point of
2325	!-- view the imposed perturbations should not be immediately dissipated
2326	!-- by the numerics. The numerical dissipation, however, acts on scales
2327	!-- up to 8 x the grid spacing. For this reason, set the turbulence
2328	!-- length scale to 8 time the grid spacing. Further, above the boundary
2329	!-- layer height, set turbulence lenght scales to zero (equivalent to not
2330	!-- imposing any perturbations) in order to save computational costs.
2331	!-- Typical time scales are derived by assuming Taylors's hypothesis,
2332	!-- using the length scales and the mean profiles of u- and v-component.
2333	DO k = nzb+1, nzt+1
2334	!
2335	!-- Determine blending parameter. Within the boundary layer length scales
2336	!-- are constant, while above lengths scales approach gradully zero,
2337	!-- i.e. imposed turbulence is not correlated in space and time,
2338	!-- just white noise, which saves computations power as the loops for the
2339	!-- computation of the filter functions depend on the length scales.
2340	!-- The value decreases to 1/10 after one length scale above the
2341	!-- ABL top.
2342	blend = MIN( 1.0_wp, EXP( d_l * zu(k) - d_l * zi_ribulk ) )
2343	!
2344	!-- Assume isotropic turbulence length scales
2345	nux(k) = MAX( INT( length_scale * ddx ), 1 ) * blend
2346	nuy(k) = MAX( INT( length_scale * ddy ), 1 ) * blend
2347	nvx(k) = MAX( INT( length_scale * ddx ), 1 ) * blend
2348	nvy(k) = MAX( INT( length_scale * ddy ), 1 ) * blend
2349	nwx(k) = MAX( INT( length_scale * ddx ), 1 ) * blend
2350	nwy(k) = MAX( INT( length_scale * ddy ), 1 ) * blend
2351	!
2352	!-- Along the vertical direction limit the length scale further by the
2353	!-- boundary-layer depth to assure that no length scales larger than
2354	!-- the boundary-layer depth are used
2355	length_scale_dum = MIN( length_scale, zi_ribulk )
2356
2357	nuz(k) = MAX( INT( length_scale_dum * ddzw(k) ), 1 ) * blend
2358	nvz(k) = MAX( INT( length_scale_dum * ddzw(k) ), 1 ) * blend
2359	nwz(k) = MAX( INT( length_scale_dum * ddzw(k) ), 1 ) * blend
2360	!
2361	!-- Limit time scales, else they become very larger for low wind speed,
2362	!-- imposing long-living inflow perturbations which in turn propagate
2363	!-- further into the model domain. Use u_init and v_init to calculate
2364	!-- the time scales, which will be equal to the inflow profiles, both,
2365	!-- in offline nesting mode or in dirichlet/radiation mode.
2366	tu(k) = MIN( dt_stg_adjust, length_scale / &
2367	( ABS( u_init(k) ) + 0.1_wp ) ) * blend
2368	tv(k) = MIN( dt_stg_adjust, length_scale / &
2369	( ABS( v_init(k) ) + 0.1_wp ) ) * blend
2370	!
2371	!-- Time scale of w-component is a mixture from u- and v-component.
2372	tw(k) = SQRT( tu(k)2 + tv(k)2 ) * blend
2373
2374	ENDDO
2375	!
2376	!-- Set bottom boundary condition for the length and time scales
2377	nux(nzb) = nux(nzb+1)
2378	nuy(nzb) = nuy(nzb+1)
2379	nuz(nzb) = nuz(nzb+1)
2380	nvx(nzb) = nvx(nzb+1)
2381	nvy(nzb) = nvy(nzb+1)
2382	nvz(nzb) = nvz(nzb+1)
2383	nwx(nzb) = nwx(nzb+1)
2384	nwy(nzb) = nwy(nzb+1)
2385	nwz(nzb) = nwz(nzb+1)
2386
2387	tu(nzb) = tu(nzb+1)
2388	tv(nzb) = tv(nzb+1)
2389	tw(nzb) = tw(nzb+1)
2390
2391
2392	END SUBROUTINE calc_length_and_time_scale
2393
2394	!------------------------------------------------------------------------------!
2395	! Description:
2396	! ------------
2397	!> Calculate scaling variables which are used for turbulence parametrization
2398	!> according to Rotach et al. (1996). Scaling variables are: friction velocity,
2399	!> boundary-layer depth, momentum velocity scale, and Obukhov length.
2400	!------------------------------------------------------------------------------!
2401	SUBROUTINE calc_scaling_variables
2402
2403	INTEGER(iwp) :: i !< loop index in x-direction
2404	INTEGER(iwp) :: j !< loop index in y-direction
2405	INTEGER(iwp) :: k !< loop index in z-direction
2406	INTEGER(iwp) :: m !< surface element index
2407
2408	REAL(wp) :: friction_vel_l !< mean friction veloctiy on subdomain
2409	REAL(wp) :: pt_surf_mean !< mean near surface temperature (at 1st grid point)
2410	REAL(wp) :: pt_surf_mean_l !< mean near surface temperature (at 1st grid point) on subdomain
2411	REAL(wp) :: scale_l_l !< mean Obukhov lenght on subdomain
2412	REAL(wp) :: shf_mean !< mean surface sensible heat flux
2413	REAL(wp) :: shf_mean_l !< mean surface sensible heat flux on subdomain
2414	REAL(wp) :: w_convective !< convective velocity scale
2415
2416	!
2417	!-- Calculate mean friction velocity, velocity scale, heat flux and
2418	!-- near-surface temperature in the model domain.
2419	pt_surf_mean_l = 0.0_wp
2420	shf_mean_l = 0.0_wp
2421	scale_l_l = 0.0_wp
2422	friction_vel_l = 0.0_wp
2423	DO m = 1, surf_def_h(0)%ns
2424	i = surf_def_h(0)%i(m)
2425	j = surf_def_h(0)%j(m)
2426	k = surf_def_h(0)%k(m)
2427	friction_vel_l = friction_vel_l + surf_def_h(0)%us(m)
2428	shf_mean_l = shf_mean_l + surf_def_h(0)%shf(m) * drho_air(k)
2429	scale_l_l = scale_l_l + surf_def_h(0)%ol(m)
2430	pt_surf_mean_l = pt_surf_mean_l + pt(k,j,i)
2431	ENDDO
2432	DO m = 1, surf_lsm_h%ns
2433	i = surf_lsm_h%i(m)
2434	j = surf_lsm_h%j(m)
2435	k = surf_lsm_h%k(m)
2436	friction_vel_l = friction_vel_l + surf_lsm_h%us(m)
2437	shf_mean_l = shf_mean_l + surf_lsm_h%shf(m) * drho_air(k)
2438	scale_l_l = scale_l_l + surf_lsm_h%ol(m)
2439	pt_surf_mean_l = pt_surf_mean_l + pt(k,j,i)
2440	ENDDO
2441	DO m = 1, surf_usm_h%ns
2442	i = surf_usm_h%i(m)
2443	j = surf_usm_h%j(m)
2444	k = surf_usm_h%k(m)
2445	friction_vel_l = friction_vel_l + surf_usm_h%us(m)
2446	shf_mean_l = shf_mean_l + surf_usm_h%shf(m) * drho_air(k)
2447	scale_l_l = scale_l_l + surf_usm_h%ol(m)
2448	pt_surf_mean_l = pt_surf_mean_l + pt(k,j,i)
2449	ENDDO
2450
2451	#if defined( __parallel )
2452	CALL MPI_ALLREDUCE( friction_vel_l, scale_us, 1, MPI_REAL, MPI_SUM, &
2453	comm2d, ierr )
2454	CALL MPI_ALLREDUCE( shf_mean_l, shf_mean, 1, MPI_REAL, MPI_SUM, &
2455	comm2d, ierr )
2456	CALL MPI_ALLREDUCE( scale_l_l, scale_l, 1, MPI_REAL, MPI_SUM, &
2457	comm2d, ierr )
2458	CALL MPI_ALLREDUCE( pt_surf_mean_l, pt_surf_mean, 1, MPI_REAL, MPI_SUM, &
2459	comm2d, ierr )
2460	#else
2461	scale_us = friction_vel_l
2462	shf_mean = shf_mean_l
2463	scale_l = scale_l_l
2464	pt_surf_mean = pt_surf_mean_l
2465	#endif
2466
2467	scale_us = scale_us / REAL( ( nx + 1 ) * ( ny + 1 ), KIND = wp )
2468	shf_mean = shf_mean / REAL( ( nx + 1 ) * ( ny + 1 ), KIND = wp )
2469	scale_l = scale_l / REAL( ( nx + 1 ) * ( ny + 1 ), KIND = wp )
2470	pt_surf_mean = pt_surf_mean / REAL( ( nx + 1 ) * ( ny + 1 ), KIND = wp )
2471	!
2472	!-- Compute mean convective velocity scale. Note, in case the mean heat flux
2473	!-- is negative, set convective velocity scale to zero.
2474	IF ( shf_mean > 0.0_wp ) THEN
2475	w_convective = ( g * shf_mean * zi_ribulk / pt_surf_mean )**( 1.0_wp / 3.0_wp )
2476	ELSE
2477	w_convective = 0.0_wp
2478	ENDIF
2479	!
2480	!-- Finally, in order to consider also neutral or stable stratification,
2481	!-- compute momentum velocity scale from u* and convective velocity scale,
2482	!-- according to Rotach et al. (1996).
2483	scale_wm = ( scale_us*3 + 0.6_wp w_convective3 )( 1.0_wp / 3.0_wp )
2484
2485	END SUBROUTINE calc_scaling_variables
2486
2487	END MODULE synthetic_turbulence_generator_mod

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