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1!> @file time_integration.f90
2!--------------------------------------------------------------------------------!
3! This file is part of PALM.
4!
5! PALM is free software: you can redistribute it and/or modify it under the terms
6! of the GNU General Public License as published by the Free Software Foundation,
7! either version 3 of the License, or (at your option) any later version.
8!
9! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
10! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
11! A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
12!
13! You should have received a copy of the GNU General Public License along with
14! PALM. If not, see <http://www.gnu.org/licenses/>.
15!
16! Copyright 1997-2015 Leibniz Universitaet Hannover
17!--------------------------------------------------------------------------------!
18!
19! Current revisions:
20! ------------------
21!
22!
23! Former revisions:
24! -----------------
25! $Id: time_integration.f90 1763 2016-02-25 13:00:19Z hellstea $
26!
27! 1762 2016-02-25 12:31:13Z hellstea
28! Introduction of nested domain feature
29!
30! 1736 2015-12-04 08:56:33Z raasch
31! no perturbations added to total domain if energy limit has been set zero
32!
33! 1691 2015-10-26 16:17:44Z maronga
34! Added option for spin-ups without land surface and radiation models. Moved calls
35! for radiation and lan surface schemes.
36!
37! 1682 2015-10-07 23:56:08Z knoop
38! Code annotations made doxygen readable
39!
40! 1671 2015-09-25 03:29:37Z raasch
41! bugfix: ghostpoint exchange for array diss in case that sgs velocities are used
42! for particles
43!
44! 1585 2015-04-30 07:05:52Z maronga
45! Moved call of radiation scheme. Added support for RRTM
46!
47! 1551 2015-03-03 14:18:16Z maronga
48! Added interface for different radiation schemes.
49!
50! 1496 2014-12-02 17:25:50Z maronga
51! Added calls for the land surface model and radiation scheme
52!
53! 1402 2014-05-09 14:25:13Z raasch
54! location messages modified
55!
56! 1384 2014-05-02 14:31:06Z raasch
57! location messages added
58!
59! 1380 2014-04-28 12:40:45Z heinze
60! CALL of nudge_ref added
61! bc_pt_t_val and bc_q_t_val are updated in case nudging is used
62!
63! 1365 2014-04-22 15:03:56Z boeske
64! Reset sums_ls_l to zero at each timestep
65! +sums_ls_l
66! Calculation of reference state (previously in subroutine calc_mean_profile)
67
68! 1342 2014-03-26 17:04:47Z kanani
69! REAL constants defined as wp-kind
70!
71! 1320 2014-03-20 08:40:49Z raasch
72! ONLY-attribute added to USE-statements,
73! kind-parameters added to all INTEGER and REAL declaration statements,
74! kinds are defined in new module kinds,
75! old module precision_kind is removed,
76! revision history before 2012 removed,
77! comment fields (!:) to be used for variable explanations added to
78! all variable declaration statements
79! 1318 2014-03-17 13:35:16Z raasch
80! module interfaces removed
81!
82! 1308 2014-03-13 14:58:42Z fricke
83! +netcdf_data_format_save
84! For masked data, parallel netcdf output is not tested so far, hence
85! netcdf_data_format is switched back to non-paralell output.
86!
87! 1276 2014-01-15 13:40:41Z heinze
88! Use LSF_DATA also in case of Dirichlet bottom boundary condition for scalars
89!
90! 1257 2013-11-08 15:18:40Z raasch
91! acc-update-host directive for timestep removed
92!
93! 1241 2013-10-30 11:36:58Z heinze
94! Generalize calc_mean_profile for wider use
95! Determine shf and qsws in dependence on data from LSF_DATA
96! Determine ug and vg in dependence on data from LSF_DATA
97! 1221 2013-09-10 08:59:13Z raasch
98! host update of arrays before timestep is called
99!
100! 1179 2013-06-14 05:57:58Z raasch
101! mean profiles for reference state are only calculated if required,
102! small bugfix for background communication
103!
104! 1171 2013-05-30 11:27:45Z raasch
105! split of prognostic_equations deactivated (comment lines), for the time being
106!
107! 1128 2013-04-12 06:19:32Z raasch
108! asynchronous transfer of ghost point data realized for acc-optimized version:
109! prognostic_equations are first called two times for those points required for
110! the left-right and north-south exchange, respectively, and then for the
111! remaining points,
112! those parts requiring global communication moved from prognostic_equations to
113! here
114!
115! 1115 2013-03-26 18:16:16Z hoffmann
116! calculation of qr and nr is restricted to precipitation
117!
118! 1113 2013-03-10 02:48:14Z raasch
119! GPU-porting of boundary conditions,
120! openACC directives updated
121! formal parameter removed from routine boundary_conds
122!
123! 1111 2013-03-08 23:54:10Z raasch
124! +internal timestep counter for cpu statistics added,
125! openACC directives updated
126!
127! 1092 2013-02-02 11:24:22Z raasch
128! unused variables removed
129!
130! 1065 2012-11-22 17:42:36Z hoffmann
131! exchange of diss (dissipation rate) in case of turbulence = .TRUE. added
132!
133! 1053 2012-11-13 17:11:03Z hoffmann
134! exchange of ghost points for nr, qr added
135!
136! 1036 2012-10-22 13:43:42Z raasch
137! code put under GPL (PALM 3.9)
138!
139! 1019 2012-09-28 06:46:45Z raasch
140! non-optimized version of prognostic_equations removed
141!
142! 1015 2012-09-27 09:23:24Z raasch
143! +call of prognostic_equations_acc
144!
145! 1001 2012-09-13 14:08:46Z raasch
146! all actions concerning leapfrog- and upstream-spline-scheme removed
147!
148! 849 2012-03-15 10:35:09Z raasch
149! advec_particles renamed lpm, first_call_advec_particles renamed first_call_lpm
150!
151! 825 2012-02-19 03:03:44Z raasch
152! wang_collision_kernel renamed wang_kernel
153!
154! Revision 1.1  1997/08/11 06:19:04  raasch
155! Initial revision
156!
157!
158! Description:
159! ------------
160!> Integration in time of the model equations, statistical analysis and graphic
161!> output
162!------------------------------------------------------------------------------!
163 SUBROUTINE time_integration
164 
165
166    USE advec_ws,                                                              &
167        ONLY:  ws_statistics
168
169    USE arrays_3d,                                                             &
170        ONLY:  diss, dzu, e, e_p, nr_p, prho, pt, pt_p, pt_init, q_init, q,    &
171               ql, ql_c, ql_v, ql_vp, qr_p, q_p, ref_state, rho, sa_p, tend,   &
172               u, u_p, v, vpt, v_p, w, w_p
173
174    USE calc_mean_profile_mod,                                                 &
175        ONLY:  calc_mean_profile
176
177    USE control_parameters,                                                    &
178        ONLY:  advected_distance_x, advected_distance_y, average_count_3d,     &
179               average_count_sp, averaging_interval, averaging_interval_pr,    &
180               averaging_interval_sp, bc_lr_cyc, bc_ns_cyc, bc_pt_t_val,       &
181               bc_q_t_val, call_psolver_at_all_substeps, cloud_droplets,       &
182               cloud_physics, constant_flux_layer, constant_heatflux,          &
183               create_disturbances, dopr_n, constant_diffusion, coupling_mode, &
184               coupling_start_time, current_timestep_number,                   &
185               disturbance_created, disturbance_energy_limit, dist_range,      &
186               do_sum, dt_3d, dt_averaging_input, dt_averaging_input_pr,       &
187               dt_coupling, dt_data_output_av, dt_disturb, dt_do2d_xy,         &
188               dt_do2d_xz, dt_do2d_yz, dt_do3d, dt_domask,dt_dopts, dt_dopr,   &
189               dt_dopr_listing, dt_dosp, dt_dots, dt_dvrp, dt_run_control,     &
190               end_time, first_call_lpm, galilei_transformation, humidity,     &
191               icloud_scheme, intermediate_timestep_count,                     &
192               intermediate_timestep_count_max, large_scale_forcing,           &
193               loop_optimization, lsf_surf, lsf_vert, masks, mid, nest_domain, &
194               netcdf_data_format, neutral, nr_timesteps_this_run, nudging,    &
195               ocean, on_device, passive_scalar, precipitation,                &
196               prho_reference, pt_reference, pt_slope_offset, random_heatflux, &
197               run_coupled, simulated_time, simulated_time_chr,                &
198               skip_time_do2d_xy, skip_time_do2d_xz, skip_time_do2d_yz,        &
199               skip_time_do3d, skip_time_domask, skip_time_dopr,               &
200               skip_time_dosp, skip_time_data_output_av, sloping_surface,      &
201               stop_dt, terminate_coupled, terminate_run, timestep_scheme,     &
202               time_coupling, time_do2d_xy, time_do2d_xz, time_do2d_yz,        &
203               time_do3d, time_domask, time_dopr, time_dopr_av,                &
204               time_dopr_listing, time_dopts, time_dosp, time_dosp_av,         &
205               time_dots, time_do_av, time_do_sla, time_disturb, time_dvrp,    &
206               time_run_control, time_since_reference_point,                   &
207               turbulence,                                                     &
208               turbulent_inflow, use_initial_profile_as_reference,             &
209               use_single_reference_value, u_gtrans, v_gtrans, ws_scheme_mom,  &
210               ws_scheme_sca
211
212    USE cpulog,                                                                &
213        ONLY:  cpu_log, log_point, log_point_s
214
215    USE indices,                                                               &
216        ONLY:  i_left, i_right, j_north, j_south, nbgp, nx, nxl, nxlg, nxr,    &
217               nxrg, nyn, nys, nzb, nzt, nzb_u_inner, nzb_v_inner
218
219    USE interaction_droplets_ptq_mod,                                          &
220        ONLY:  interaction_droplets_ptq
221
222    USE kinds
223
224    USE land_surface_model_mod,                                                &
225        ONLY:  land_surface, lsm_energy_balance, lsm_soil_model,               &
226               skip_time_do_lsm
227
228    USE ls_forcing_mod,                                                        &
229        ONLY:  ls_forcing_surf, ls_forcing_vert
230
231    USE nudge_mod,                                                             &
232        ONLY:  calc_tnudge, nudge_ref
233
234    USE particle_attributes,                                                   &
235        ONLY:  particle_advection, particle_advection_start,                   &
236               use_sgs_for_particles, wang_kernel
237
238    USE pegrid
239
240#if defined( PMC_ACTIVE )
241    USE pmc_interface,                                                         &
242        ONLY:  client_to_server, nesting_mode,                                 &
243               pmci_ensure_nest_mass_conservation, pmci_client_datatrans,      &
244               pmci_client_initialize, pmci_client_synchronize,                &
245               pmci_server_datatrans, pmci_server_initialize,                  &
246               pmci_server_synchronize, pmci_update_new, server_to_client
247#endif
248
249    USE production_e_mod,                                                      &
250        ONLY:  production_e_init
251
252    USE progress_bar,                                                          &
253        ONLY:  finish_progress_bar, output_progress_bar
254
255    USE prognostic_equations_mod,                                              &
256        ONLY:  prognostic_equations_acc, prognostic_equations_cache,           &
257               prognostic_equations_vector
258
259    USE radiation_model_mod,                                                   &
260        ONLY: dt_radiation, force_radiation_call, radiation,                   &
261              radiation_clearsky, radiation_rrtmg, radiation_scheme,           &
262              skip_time_do_radiation, time_radiation
263
264    USE statistics,                                                            &
265        ONLY:  flow_statistics_called, hom, pr_palm, sums_ls_l
266
267    USE surface_layer_fluxes_mod,                                              &
268        ONLY:  surface_layer_fluxes
269
270    USE user_actions_mod,                                                      &
271        ONLY:  user_actions
272
273    IMPLICIT NONE
274
275    CHARACTER (LEN=9) ::  time_to_string          !<
276
277    INTEGER(iwp)      ::  netcdf_data_format_save !<
278
279!
280!-- At the beginning of a simulation determine the time step as well as
281!-- determine and print out the run control parameters
282    IF ( simulated_time == 0.0_wp )  CALL timestep
283
284    CALL run_control
285
286
287!
288!-- Data exchange between coupled models in case that a call has been omitted
289!-- at the end of the previous run of a job chain.
290    IF ( coupling_mode /= 'uncoupled'  .AND.  run_coupled )  THEN
291!
292!--    In case of model termination initiated by the local model the coupler
293!--    must not be called because this would again cause an MPI hang.
294       DO WHILE ( time_coupling >= dt_coupling .AND. terminate_coupled == 0 )
295          CALL surface_coupler
296          time_coupling = time_coupling - dt_coupling
297       ENDDO
298       IF (time_coupling == 0.0_wp .AND. time_since_reference_point < dt_coupling)&
299       THEN
300          time_coupling = time_since_reference_point
301       ENDIF
302    ENDIF
303
304#if defined( PMC_ACTIVE )
305!
306!-- TO_DO: try to give more meaningful comments here
307!-- Domain nesting: From server to client commmunication
308!-- ( direction=SERVER_TO_CLIENT )
309!-- Nest initial conditions
310!
311!-- Send initial condition data from server to client
312    CALL pmci_server_initialize
313!
314!-- Receive and interpolate initial data on client
315    CALL pmci_client_initialize
316!
317!-- TO_DO, maybe removed
318!-- Obs. Nesting may be unnecessary at this point.
319!
320!-- Nest boundary conditions
321    CALL pmci_server_datatrans( server_to_client )
322    CALL pmci_client_datatrans( server_to_client )
323
324    IF ( nesting_mode == 'two-way' )  THEN
325       CALL pmci_server_datatrans( client_to_server )
326       CALL pmci_client_datatrans( client_to_server )
327!
328!--    Exchange_horiz is needed for all server-domains after the anterpolation
329       CALL exchange_horiz( u, nbgp )
330       CALL exchange_horiz( v, nbgp )
331       CALL exchange_horiz( w, nbgp )
332       CALL exchange_horiz( pt, nbgp )
333       IF ( .NOT. constant_diffusion )  CALL exchange_horiz( e, nbgp )
334       intermediate_timestep_count = 0
335       CALL pres
336    ENDIF
337!
338!-- Correct the w top-BC in nest domains to ensure mass conservation.
339!-- Copy the interpolated/anterpolated boundary values to the _p
340!-- arrays, too, to make sure the interpolated/anterpolated boundary
341!-- values are carried over from one RK inner step to another.
342!-- These actions must not be done for the root domain.
343    IF ( nest_domain )  THEN
344       CALL pmci_ensure_nest_mass_conservation
345       CALL pmci_update_new
346    ENDIF
347#endif
348
349#if defined( __dvrp_graphics )
350!
351!-- Time measurement with dvrp software 
352    CALL DVRP_LOG_EVENT( 2, current_timestep_number )
353#endif
354
355    CALL location_message( 'start with time-stepping', .TRUE. )
356!
357!-- Start of the time loop
358    DO  WHILE ( simulated_time < end_time  .AND.  .NOT. stop_dt  .AND. &
359                .NOT. terminate_run )
360
361       CALL cpu_log( log_point_s(10), 'timesteps', 'start' )
362
363!
364!--    Determine size of next time step
365       IF ( simulated_time /= 0.0_wp )  THEN
366          CALL timestep
367
368#if defined( PMC_ACTIVE )
369!
370!--       TO_DO: try to give more detailed and meaningful comments here
371!--       Server side must be called first
372          CALL pmci_server_synchronize
373          CALL pmci_client_synchronize
374#endif
375       ENDIF
376
377
378!
379!--    Determine ug, vg and w_subs in dependence on data from external file
380!--    LSF_DATA
381       IF ( large_scale_forcing .AND. lsf_vert )  THEN
382           CALL ls_forcing_vert ( simulated_time )
383           sums_ls_l = 0.0_wp
384       ENDIF
385
386!
387!--    Set pt_init and q_init to the current profiles taken from
388!--    NUDGING_DATA
389       IF ( nudging )  THEN
390           CALL nudge_ref ( simulated_time )
391!
392!--        Store temperature gradient at the top boundary for possible Neumann
393!--        boundary condition
394           bc_pt_t_val = ( pt_init(nzt+1) - pt_init(nzt) ) / dzu(nzt+1)
395           bc_q_t_val  = ( q_init(nzt+1) - q_init(nzt) ) / dzu(nzt+1)
396       ENDIF
397
398!
399!--    Execute the user-defined actions
400       CALL user_actions( 'before_timestep' )
401
402!
403!--    Start of intermediate step loop
404       intermediate_timestep_count = 0
405       DO  WHILE ( intermediate_timestep_count < &
406                   intermediate_timestep_count_max )
407
408          intermediate_timestep_count = intermediate_timestep_count + 1
409
410!
411!--       Set the steering factors for the prognostic equations which depend
412!--       on the timestep scheme
413          CALL timestep_scheme_steering
414
415!
416!--       Calculate those variables needed in the tendency terms which need
417!--       global communication
418          IF ( .NOT. use_single_reference_value  .AND. &
419               .NOT. use_initial_profile_as_reference )  THEN
420!
421!--          Horizontally averaged profiles to be used as reference state in
422!--          buoyancy terms (WARNING: only the respective last call of
423!--          calc_mean_profile defines the reference state!)
424             IF ( .NOT. neutral )  THEN
425                CALL calc_mean_profile( pt, 4 )
426                ref_state(:)  = hom(:,1,4,0) ! this is used in the buoyancy term
427             ENDIF
428             IF ( ocean )  THEN
429                CALL calc_mean_profile( rho, 64 )
430                ref_state(:)  = hom(:,1,64,0)
431             ENDIF
432             IF ( humidity )  THEN
433                CALL calc_mean_profile( vpt, 44 )
434                ref_state(:)  = hom(:,1,44,0)
435             ENDIF
436
437          ENDIF
438
439          IF ( .NOT. constant_diffusion )  CALL production_e_init
440          IF ( ( ws_scheme_mom .OR. ws_scheme_sca )  .AND.  &
441               intermediate_timestep_count == 1 )  CALL ws_statistics
442!
443!--       In case of nudging calculate current nudging time scale and horizontal
444!--       means of u, v, pt and q
445          IF ( nudging )  THEN
446             CALL calc_tnudge( simulated_time )
447             CALL calc_mean_profile( u, 1 )
448             CALL calc_mean_profile( v, 2 )
449             CALL calc_mean_profile( pt, 4 )
450             CALL calc_mean_profile( q, 41 )
451          ENDIF
452
453!
454!--       Solve the prognostic equations. A fast cache optimized version with
455!--       only one single loop is used in case of Piascek-Williams advection
456!--       scheme. NEC vector machines use a different version, because
457!--       in the other versions a good vectorization is prohibited due to
458!--       inlining problems.
459          IF ( loop_optimization == 'cache' )  THEN
460             CALL prognostic_equations_cache
461          ELSEIF ( loop_optimization == 'vector' )  THEN
462             CALL prognostic_equations_vector
463          ELSEIF ( loop_optimization == 'acc' )  THEN
464             i_left  = nxl;         i_right = nxr
465             j_south = nys;         j_north = nyn
466             CALL prognostic_equations_acc
467
468!             i_left  = nxl;         i_right = nxl+nbgp-1
469!             j_south = nys;         j_north = nyn
470!             CALL prognostic_equations_acc
471!             i_left  = nxr-nbgp+1;  i_right = nxr
472!             j_south = nys;         j_north = nyn
473!             CALL prognostic_equations_acc
474
475!
476!--          Exchange of ghost points (lateral boundary conditions)
477             IF ( background_communication )  THEN
478
479                CALL cpu_log( log_point(26), 'exchange-horiz-progn', 'start' )
480               
481                send_receive = 'lr'
482                sendrecv_in_background = .TRUE.
483                req          = 0
484                req_count    = 0
485
486                IF ( numprocs == 1 )  THEN    ! workaround for single-core GPU runs
487                   on_device = .TRUE.         ! to be removed after complete porting
488                ELSE                          ! of ghost point exchange
489                   !$acc update host( e_p, pt_p, u_p, v_p, w_p )
490                ENDIF
491
492                CALL exchange_horiz( u_p, nbgp )
493                CALL exchange_horiz( v_p, nbgp )
494                CALL exchange_horiz( w_p, nbgp )
495                CALL exchange_horiz( pt_p, nbgp )
496                IF ( .NOT. constant_diffusion )  CALL exchange_horiz( e_p, nbgp )
497                IF ( ocean )  THEN
498                   CALL exchange_horiz( sa_p, nbgp )
499                   CALL exchange_horiz( rho, nbgp )
500                  CALL exchange_horiz( prho, nbgp )
501                ENDIF
502                IF (humidity  .OR.  passive_scalar)  THEN
503                   CALL exchange_horiz( q_p, nbgp )
504                   IF ( cloud_physics .AND. icloud_scheme == 0 )  THEN
505                      CALL exchange_horiz( qr_p, nbgp )
506                      CALL exchange_horiz( nr_p, nbgp )
507                   ENDIF
508                ENDIF
509                IF ( cloud_droplets )  THEN
510                   CALL exchange_horiz( ql, nbgp )
511                   CALL exchange_horiz( ql_c, nbgp )
512                   CALL exchange_horiz( ql_v, nbgp )
513                   CALL exchange_horiz( ql_vp, nbgp )
514                ENDIF
515                IF ( wang_kernel  .OR.  turbulence  .OR.  use_sgs_for_particles ) &
516                THEN
517                   CALL exchange_horiz( diss, nbgp )
518                ENDIF
519
520                IF ( numprocs == 1 )  THEN    ! workaround for single-core GPU runs
521                   on_device = .FALSE.        ! to be removed after complete porting
522                ELSE                          ! of ghost point exchange
523                   !$acc update device( e_p, pt_p, u_p, v_p, w_p )
524                ENDIF
525
526                sendrecv_in_background = .FALSE.
527
528                CALL cpu_log( log_point(26), 'exchange-horiz-progn', 'pause' )
529
530             ENDIF
531
532!             i_left  = nxl+nbgp;    i_right = nxr-nbgp
533!             j_south = nys;         j_north = nys+nbgp-1
534!             CALL prognostic_equations_acc
535!             i_left  = nxl+nbgp;    i_right = nxr-nbgp
536!             j_south = nyn-nbgp+1;  j_north = nyn
537!             CALL prognostic_equations_acc
538
539             IF ( background_communication )  THEN
540                CALL cpu_log( log_point(41), 'exchange-horiz-wait', 'start' )
541#if defined( __parallel )
542                CALL MPI_WAITALL( req_count, req, wait_stat, ierr )
543#endif
544                CALL cpu_log( log_point(41), 'exchange-horiz-wait', 'pause' )
545
546                CALL cpu_log( log_point(26), 'exchange-horiz-progn', 'continue' )
547
548                send_receive = 'ns'
549                sendrecv_in_background = .TRUE.
550                req          = 0
551                req_count    = 0
552
553                IF ( numprocs == 1 )  THEN    ! workaround for single-core GPU runs
554                   on_device = .TRUE.         ! to be removed after complete porting
555                ELSE                          ! of ghost point exchange
556                   !$acc update host( e_p, pt_p, u_p, v_p, w_p )
557                ENDIF
558
559                CALL exchange_horiz( u_p, nbgp )
560                CALL exchange_horiz( v_p, nbgp )
561                CALL exchange_horiz( w_p, nbgp )
562                CALL exchange_horiz( pt_p, nbgp )
563                IF ( .NOT. constant_diffusion )  CALL exchange_horiz( e_p, nbgp )
564                IF ( ocean )  THEN
565                   CALL exchange_horiz( sa_p, nbgp )
566                   CALL exchange_horiz( rho, nbgp )
567                  CALL exchange_horiz( prho, nbgp )
568                ENDIF
569                IF (humidity  .OR.  passive_scalar)  THEN
570                   CALL exchange_horiz( q_p, nbgp )
571                   IF ( cloud_physics .AND. icloud_scheme == 0 )  THEN
572                      CALL exchange_horiz( qr_p, nbgp )
573                      CALL exchange_horiz( nr_p, nbgp )
574                   ENDIF
575                ENDIF
576                IF ( cloud_droplets )  THEN
577                   CALL exchange_horiz( ql, nbgp )
578                   CALL exchange_horiz( ql_c, nbgp )
579                   CALL exchange_horiz( ql_v, nbgp )
580                   CALL exchange_horiz( ql_vp, nbgp )
581                ENDIF
582                IF ( wang_kernel  .OR.  turbulence  .OR.  use_sgs_for_particles ) &
583                THEN
584                   CALL exchange_horiz( diss, nbgp )
585                ENDIF
586
587                IF ( numprocs == 1 )  THEN    ! workaround for single-core GPU runs
588                   on_device = .FALSE.        ! to be removed after complete porting
589                ELSE                          ! of ghost point exchange
590                   !$acc update device( e_p, pt_p, u_p, v_p, w_p )
591                ENDIF
592
593                sendrecv_in_background = .FALSE.
594
595                CALL cpu_log( log_point(26), 'exchange-horiz-progn', 'stop' )
596
597             ENDIF
598
599!             i_left  = nxl+nbgp;    i_right = nxr-nbgp
600!             j_south = nys+nbgp;    j_north = nyn-nbgp
601!             CALL prognostic_equations_acc
602
603             IF ( background_communication )  THEN
604                CALL cpu_log( log_point(41), 'exchange-horiz-wait', 'continue' )
605#if defined( __parallel )
606                CALL MPI_WAITALL( req_count, req, wait_stat, ierr )
607#endif
608                send_receive = 'al'
609                CALL cpu_log( log_point(41), 'exchange-horiz-wait', 'stop' )
610             ENDIF
611
612          ENDIF
613
614!
615!--       Particle transport/physics with the Lagrangian particle model
616!--       (only once during intermediate steps, because it uses an Euler-step)
617!--       ### particle model should be moved before prognostic_equations, in order
618!--       to regard droplet interactions directly
619          IF ( particle_advection  .AND.                         &
620               simulated_time >= particle_advection_start  .AND. &
621               intermediate_timestep_count == 1 )  THEN
622             CALL lpm
623             first_call_lpm = .FALSE.
624          ENDIF
625
626!
627!--       Interaction of droplets with temperature and specific humidity.
628!--       Droplet condensation and evaporation is calculated within
629!--       advec_particles.
630          IF ( cloud_droplets  .AND.  &
631               intermediate_timestep_count == intermediate_timestep_count_max )&
632          THEN
633             CALL interaction_droplets_ptq
634          ENDIF
635
636!
637!--       Exchange of ghost points (lateral boundary conditions)
638          IF ( .NOT. background_communication )  THEN
639
640             CALL cpu_log( log_point(26), 'exchange-horiz-progn', 'start' )
641
642             IF ( numprocs == 1 )  THEN    ! workaround for single-core GPU runs
643                on_device = .TRUE.         ! to be removed after complete porting
644             ELSE                          ! of ghost point exchange
645                !$acc update host( e_p, pt_p, u_p, v_p, w_p )
646             ENDIF
647
648             CALL exchange_horiz( u_p, nbgp )
649             CALL exchange_horiz( v_p, nbgp )
650             CALL exchange_horiz( w_p, nbgp )
651             CALL exchange_horiz( pt_p, nbgp )
652             IF ( .NOT. constant_diffusion )  CALL exchange_horiz( e_p, nbgp )
653             IF ( ocean )  THEN
654                CALL exchange_horiz( sa_p, nbgp )
655                CALL exchange_horiz( rho, nbgp )
656                CALL exchange_horiz( prho, nbgp )
657             ENDIF
658             IF (humidity  .OR.  passive_scalar)  THEN
659                CALL exchange_horiz( q_p, nbgp )
660                IF ( cloud_physics .AND. icloud_scheme == 0  .AND.  &
661                     precipitation )  THEN
662                   CALL exchange_horiz( qr_p, nbgp )
663                   CALL exchange_horiz( nr_p, nbgp )
664                ENDIF
665             ENDIF
666             IF ( cloud_droplets )  THEN
667                CALL exchange_horiz( ql, nbgp )
668                CALL exchange_horiz( ql_c, nbgp )
669                CALL exchange_horiz( ql_v, nbgp )
670                CALL exchange_horiz( ql_vp, nbgp )
671             ENDIF
672             IF ( wang_kernel  .OR.  turbulence  .OR.  use_sgs_for_particles ) &
673             THEN
674                CALL exchange_horiz( diss, nbgp )
675             ENDIF
676
677             IF ( numprocs == 1 )  THEN    ! workaround for single-core GPU runs
678                on_device = .FALSE.        ! to be removed after complete porting
679             ELSE                          ! of ghost point exchange
680                !$acc update device( e_p, pt_p, u_p, v_p, w_p )
681             ENDIF
682
683             CALL cpu_log( log_point(26), 'exchange-horiz-progn', 'stop' )
684
685          ENDIF
686
687!
688!--       Boundary conditions for the prognostic quantities (except of the
689!--       velocities at the outflow in case of a non-cyclic lateral wall)
690          CALL boundary_conds
691
692!
693!--       Swap the time levels in preparation for the next time step.
694          CALL swap_timelevel
695
696#if defined( PMC_ACTIVE )
697!
698!--       TO_DO: try to give more meaningful comments here
699!--       Domain nesting
700!--       Note that the nesting operations are omitted intentionally on the
701!--       first two RK-substeps.
702          CALL cpu_log( log_point(60), 'nesting', 'start' )
703!
704!--       From server to client commmunication ( direction=SERVER_TO_CLIENT )
705          CALL pmci_server_datatrans( server_to_client )
706          CALL pmci_client_datatrans( server_to_client )
707
708          IF ( nesting_mode == 'two-way' )  THEN
709!
710!--          From client to server commmunication ( direction=CLIENT_TO_SERVER )
711             CALL pmci_server_datatrans( client_to_server )
712             CALL pmci_client_datatrans( client_to_server )
713!
714!--          Exchange_horiz is needed for all server-domains after the
715!--          anterpolation
716             CALL exchange_horiz( u, nbgp )
717             CALL exchange_horiz( v, nbgp )
718             CALL exchange_horiz( w, nbgp )
719             CALL exchange_horiz( pt, nbgp )
720             IF ( humidity  .OR.  passive_scalar )  THEN
721                CALL exchange_horiz( q, nbgp )
722             ENDIF
723             IF ( .NOT. constant_diffusion )  CALL exchange_horiz( e, nbgp )
724          ENDIF
725!
726!--       Correct the w top-BC in nest domains to ensure mass conservation.
727!--       This action must never be done for the root domain.
728          IF ( nest_domain )  THEN
729             CALL pmci_ensure_nest_mass_conservation
730!
731!--          pmc_update_new is not necessary if nesting is made at each substep.
732             CALL pmci_update_new
733          ENDIF
734
735          CALL cpu_log( log_point(60), 'nesting', 'stop' )
736#endif
737
738!
739!--       Temperature offset must be imposed at cyclic boundaries in x-direction
740!--       when a sloping surface is used
741          IF ( sloping_surface )  THEN
742             IF ( nxl ==  0 )  pt(:,:,nxlg:nxl-1) = pt(:,:,nxlg:nxl-1) - &
743                                                    pt_slope_offset
744             IF ( nxr == nx )  pt(:,:,nxr+1:nxrg) = pt(:,:,nxr+1:nxrg) + &
745                                                    pt_slope_offset
746          ENDIF
747
748!
749!--       Impose a turbulent inflow using the recycling method
750          IF ( turbulent_inflow )  CALL  inflow_turbulence
751
752!
753!--       Impose a random perturbation on the horizontal velocity field
754          IF ( create_disturbances  .AND.                                      &
755               ( call_psolver_at_all_substeps  .AND.                           &
756               intermediate_timestep_count == intermediate_timestep_count_max )&
757          .OR. ( .NOT. call_psolver_at_all_substeps  .AND.                     &
758               intermediate_timestep_count == 1 ) )                            &
759          THEN
760             time_disturb = time_disturb + dt_3d
761             IF ( time_disturb >= dt_disturb )  THEN
762                !$acc update host( u, v )
763                IF ( numprocs == 1 )  on_device = .FALSE.  ! workaround, remove later
764                IF ( disturbance_energy_limit /= 0.0_wp  .AND.                 &
765                     hom(nzb+5,1,pr_palm,0) < disturbance_energy_limit )  THEN
766                   CALL disturb_field( nzb_u_inner, tend, u )
767                   CALL disturb_field( nzb_v_inner, tend, v )
768                ELSEIF ( .NOT. bc_lr_cyc  .OR.  .NOT. bc_ns_cyc )  THEN
769!
770!--                Runs with a non-cyclic lateral wall need perturbations
771!--                near the inflow throughout the whole simulation
772                   dist_range = 1
773                   CALL disturb_field( nzb_u_inner, tend, u )
774                   CALL disturb_field( nzb_v_inner, tend, v )
775                   dist_range = 0
776                ENDIF
777                IF ( numprocs == 1 )  on_device = .TRUE.  ! workaround, remove later
778                !$acc update device( u, v )
779                time_disturb = time_disturb - dt_disturb
780             ENDIF
781          ENDIF
782
783!
784!--       Reduce the velocity divergence via the equation for perturbation
785!--       pressure.
786          IF ( intermediate_timestep_count == 1  .OR. &
787                call_psolver_at_all_substeps )  THEN
788             CALL pres
789          ENDIF
790
791!
792!--       If required, compute liquid water content
793          IF ( cloud_physics )  THEN
794             CALL calc_liquid_water_content
795             !$acc update device( ql )
796          ENDIF
797!
798!--       If required, compute virtual potential temperature
799          IF ( humidity )  THEN
800             CALL compute_vpt
801             !$acc update device( vpt )
802          ENDIF
803
804!
805!--       Compute the diffusion quantities
806          IF ( .NOT. constant_diffusion )  THEN
807
808!
809!--          Determine surface fluxes shf and qsws and surface values
810!--          pt_surface and q_surface in dependence on data from external
811!--          file LSF_DATA respectively
812             IF ( ( large_scale_forcing .AND. lsf_surf ) .AND. &
813                 intermediate_timestep_count == intermediate_timestep_count_max )&
814             THEN
815                CALL ls_forcing_surf ( simulated_time )
816             ENDIF
817
818!
819!--          First the vertical fluxes in the surface (constant flux) layer are computed
820             IF ( constant_flux_layer )  THEN
821                CALL cpu_log( log_point(19), 'surface_layer_fluxes', 'start' )
822                CALL surface_layer_fluxes
823                CALL cpu_log( log_point(19), 'surface_layer_fluxes', 'stop' )
824             ENDIF
825
826!
827!--          If required, solve the energy balance for the surface and run soil
828!--          model
829             IF ( land_surface .AND. simulated_time > skip_time_do_lsm)  THEN
830
831                CALL cpu_log( log_point(54), 'land_surface', 'start' )
832                CALL lsm_energy_balance
833                CALL lsm_soil_model
834                CALL cpu_log( log_point(54), 'land_surface', 'stop' )
835             ENDIF
836!
837!--          Compute the diffusion coefficients
838             CALL cpu_log( log_point(17), 'diffusivities', 'start' )
839             IF ( .NOT. humidity ) THEN
840                IF ( ocean )  THEN
841                   CALL diffusivities( prho, prho_reference )
842                ELSE
843                   CALL diffusivities( pt, pt_reference )
844                ENDIF
845             ELSE
846                CALL diffusivities( vpt, pt_reference )
847             ENDIF
848             CALL cpu_log( log_point(17), 'diffusivities', 'stop' )
849
850          ENDIF
851
852!
853!--       If required, calculate radiative fluxes and heating rates
854          IF ( radiation .AND. intermediate_timestep_count                     &
855               == intermediate_timestep_count_max .AND. simulated_time >    &
856               skip_time_do_radiation )  THEN
857
858               time_radiation = time_radiation + dt_3d
859
860             IF ( time_radiation >= dt_radiation .OR. force_radiation_call )   &
861             THEN
862
863                CALL cpu_log( log_point(50), 'radiation', 'start' )
864
865                IF ( .NOT. force_radiation_call )  THEN
866                   time_radiation = time_radiation - dt_radiation
867                ELSE
868                   WRITE(9,*) "Unscheduled radiation call at ", simulated_time
869                   CALL LOCAL_FLUSH ( 9 )
870                ENDIF
871
872                IF ( radiation_scheme == 'clear-sky' )  THEN
873                   CALL radiation_clearsky
874                ELSEIF ( radiation_scheme == 'rrtmg' )  THEN
875                   CALL radiation_rrtmg
876                ENDIF
877
878                CALL cpu_log( log_point(50), 'radiation', 'stop' )
879             ENDIF
880          ENDIF
881
882       ENDDO   ! Intermediate step loop
883
884!
885!--    Increase simulation time and output times
886       nr_timesteps_this_run      = nr_timesteps_this_run + 1
887       current_timestep_number    = current_timestep_number + 1
888       simulated_time             = simulated_time   + dt_3d
889       simulated_time_chr         = time_to_string( simulated_time )
890       time_since_reference_point = simulated_time - coupling_start_time
891
892       IF ( simulated_time >= skip_time_data_output_av )  THEN
893          time_do_av         = time_do_av       + dt_3d
894       ENDIF
895       IF ( simulated_time >= skip_time_do2d_xy )  THEN
896          time_do2d_xy       = time_do2d_xy     + dt_3d
897       ENDIF
898       IF ( simulated_time >= skip_time_do2d_xz )  THEN
899          time_do2d_xz       = time_do2d_xz     + dt_3d
900       ENDIF
901       IF ( simulated_time >= skip_time_do2d_yz )  THEN
902          time_do2d_yz       = time_do2d_yz     + dt_3d
903       ENDIF
904       IF ( simulated_time >= skip_time_do3d    )  THEN
905          time_do3d          = time_do3d        + dt_3d
906       ENDIF
907       DO  mid = 1, masks
908          IF ( simulated_time >= skip_time_domask(mid) )  THEN
909             time_domask(mid)= time_domask(mid) + dt_3d
910          ENDIF
911       ENDDO
912       time_dvrp          = time_dvrp        + dt_3d
913       IF ( simulated_time >= skip_time_dosp )  THEN
914          time_dosp       = time_dosp        + dt_3d
915       ENDIF
916       time_dots          = time_dots        + dt_3d
917       IF ( .NOT. first_call_lpm )  THEN
918          time_dopts      = time_dopts       + dt_3d
919       ENDIF
920       IF ( simulated_time >= skip_time_dopr )  THEN
921          time_dopr       = time_dopr        + dt_3d
922       ENDIF
923       time_dopr_listing          = time_dopr_listing        + dt_3d
924       time_run_control   = time_run_control + dt_3d
925
926!
927!--    Data exchange between coupled models
928       IF ( coupling_mode /= 'uncoupled'  .AND.  run_coupled )  THEN
929          time_coupling = time_coupling + dt_3d
930
931!
932!--       In case of model termination initiated by the local model
933!--       (terminate_coupled > 0), the coupler must be skipped because it would
934!--       cause an MPI intercomminucation hang.
935!--       If necessary, the coupler will be called at the beginning of the
936!--       next restart run.
937          DO WHILE ( time_coupling >= dt_coupling .AND. terminate_coupled == 0 )
938             CALL surface_coupler
939             time_coupling = time_coupling - dt_coupling
940          ENDDO
941       ENDIF
942
943!
944!--    Execute user-defined actions
945       CALL user_actions( 'after_integration' )
946
947!
948!--    If Galilei transformation is used, determine the distance that the
949!--    model has moved so far
950       IF ( galilei_transformation )  THEN
951          advected_distance_x = advected_distance_x + u_gtrans * dt_3d
952          advected_distance_y = advected_distance_y + v_gtrans * dt_3d
953       ENDIF
954
955!
956!--    Check, if restart is necessary (because cpu-time is expiring or
957!--    because it is forced by user) and set stop flag
958!--    This call is skipped if the remote model has already initiated a restart.
959       IF ( .NOT. terminate_run )  CALL check_for_restart
960
961!
962!--    Carry out statistical analysis and output at the requested output times.
963!--    The MOD function is used for calculating the output time counters (like
964!--    time_dopr) in order to regard a possible decrease of the output time
965!--    interval in case of restart runs
966
967!
968!--    Set a flag indicating that so far no statistics have been created
969!--    for this time step
970       flow_statistics_called = .FALSE.
971
972!
973!--    If required, call flow_statistics for averaging in time
974       IF ( averaging_interval_pr /= 0.0_wp  .AND.  &
975            ( dt_dopr - time_dopr ) <= averaging_interval_pr  .AND.  &
976            simulated_time >= skip_time_dopr )  THEN
977          time_dopr_av = time_dopr_av + dt_3d
978          IF ( time_dopr_av >= dt_averaging_input_pr )  THEN
979             do_sum = .TRUE.
980             time_dopr_av = MOD( time_dopr_av, &
981                                    MAX( dt_averaging_input_pr, dt_3d ) )
982          ENDIF
983       ENDIF
984       IF ( do_sum )  CALL flow_statistics
985
986!
987!--    Sum-up 3d-arrays for later output of time-averaged 2d/3d/masked data
988       IF ( averaging_interval /= 0.0_wp  .AND.                                &
989            ( dt_data_output_av - time_do_av ) <= averaging_interval  .AND. &
990            simulated_time >= skip_time_data_output_av )                    &
991       THEN
992          time_do_sla = time_do_sla + dt_3d
993          IF ( time_do_sla >= dt_averaging_input )  THEN
994             CALL sum_up_3d_data
995             average_count_3d = average_count_3d + 1
996             time_do_sla = MOD( time_do_sla, MAX( dt_averaging_input, dt_3d ) )
997          ENDIF
998       ENDIF
999
1000!
1001!--    Calculate spectra for time averaging
1002       IF ( averaging_interval_sp /= 0.0_wp  .AND.  &
1003            ( dt_dosp - time_dosp ) <= averaging_interval_sp  .AND.  &
1004            simulated_time >= skip_time_dosp )  THEN
1005          time_dosp_av = time_dosp_av + dt_3d
1006          IF ( time_dosp_av >= dt_averaging_input_pr )  THEN
1007             CALL calc_spectra
1008             time_dosp_av = MOD( time_dosp_av, &
1009                                 MAX( dt_averaging_input_pr, dt_3d ) )
1010          ENDIF
1011       ENDIF
1012
1013!
1014!--    Computation and output of run control parameters.
1015!--    This is also done whenever perturbations have been imposed
1016       IF ( time_run_control >= dt_run_control  .OR.                     &
1017            timestep_scheme(1:5) /= 'runge'  .OR.  disturbance_created ) &
1018       THEN
1019          CALL run_control
1020          IF ( time_run_control >= dt_run_control )  THEN
1021             time_run_control = MOD( time_run_control, &
1022                                     MAX( dt_run_control, dt_3d ) )
1023          ENDIF
1024       ENDIF
1025
1026!
1027!--    Profile output (ASCII) on file
1028       IF ( time_dopr_listing >= dt_dopr_listing )  THEN
1029          CALL print_1d
1030          time_dopr_listing = MOD( time_dopr_listing, MAX( dt_dopr_listing, &
1031                                                           dt_3d ) )
1032       ENDIF
1033
1034!
1035!--    Graphic output for PROFIL
1036       IF ( time_dopr >= dt_dopr )  THEN
1037          IF ( dopr_n /= 0 )  CALL data_output_profiles
1038          time_dopr = MOD( time_dopr, MAX( dt_dopr, dt_3d ) )
1039          time_dopr_av = 0.0_wp    ! due to averaging (see above)
1040       ENDIF
1041
1042!
1043!--    Graphic output for time series
1044       IF ( time_dots >= dt_dots )  THEN
1045          CALL data_output_tseries
1046          time_dots = MOD( time_dots, MAX( dt_dots, dt_3d ) )
1047       ENDIF
1048
1049!
1050!--    Output of spectra (formatted for use with PROFIL), in case of no
1051!--    time averaging, spectra has to be calculated before
1052       IF ( time_dosp >= dt_dosp )  THEN
1053          IF ( average_count_sp == 0 )  CALL calc_spectra
1054          CALL data_output_spectra
1055          time_dosp = MOD( time_dosp, MAX( dt_dosp, dt_3d ) )
1056       ENDIF
1057
1058!
1059!--    2d-data output (cross-sections)
1060       IF ( time_do2d_xy >= dt_do2d_xy )  THEN
1061          CALL data_output_2d( 'xy', 0 )
1062          time_do2d_xy = MOD( time_do2d_xy, MAX( dt_do2d_xy, dt_3d ) )
1063       ENDIF
1064       IF ( time_do2d_xz >= dt_do2d_xz )  THEN
1065          CALL data_output_2d( 'xz', 0 )
1066          time_do2d_xz = MOD( time_do2d_xz, MAX( dt_do2d_xz, dt_3d ) )
1067       ENDIF
1068       IF ( time_do2d_yz >= dt_do2d_yz )  THEN
1069          CALL data_output_2d( 'yz', 0 )
1070          time_do2d_yz = MOD( time_do2d_yz, MAX( dt_do2d_yz, dt_3d ) )
1071       ENDIF
1072
1073!
1074!--    3d-data output (volume data)
1075       IF ( time_do3d >= dt_do3d )  THEN
1076          CALL data_output_3d( 0 )
1077          time_do3d = MOD( time_do3d, MAX( dt_do3d, dt_3d ) )
1078       ENDIF
1079
1080!
1081!--    masked data output
1082!--    Parallel netcdf output is not tested so far for masked data, hence
1083!--    netcdf_data_format is switched back to non-paralell output.
1084       netcdf_data_format_save = netcdf_data_format
1085       IF ( netcdf_data_format == 5 ) netcdf_data_format = 3
1086       IF ( netcdf_data_format == 6 ) netcdf_data_format = 4
1087       DO  mid = 1, masks
1088          IF ( time_domask(mid) >= dt_domask(mid) )  THEN
1089             CALL data_output_mask( 0 )
1090             time_domask(mid) = MOD( time_domask(mid),  &
1091                                     MAX( dt_domask(mid), dt_3d ) )
1092          ENDIF
1093       ENDDO
1094       netcdf_data_format = netcdf_data_format_save
1095
1096!
1097!--    Output of time-averaged 2d/3d/masked data
1098       IF ( time_do_av >= dt_data_output_av )  THEN
1099          CALL average_3d_data
1100          CALL data_output_2d( 'xy', 1 )
1101          CALL data_output_2d( 'xz', 1 )
1102          CALL data_output_2d( 'yz', 1 )
1103          CALL data_output_3d( 1 )
1104!--       Parallel netcdf output is not tested so far for masked data, hence
1105!--       netcdf_data_format is switched back to non-paralell output.
1106          netcdf_data_format_save = netcdf_data_format
1107          IF ( netcdf_data_format == 5 ) netcdf_data_format = 3
1108          IF ( netcdf_data_format == 6 ) netcdf_data_format = 4
1109          DO  mid = 1, masks
1110             CALL data_output_mask( 1 )
1111          ENDDO
1112          netcdf_data_format = netcdf_data_format_save
1113          time_do_av = MOD( time_do_av, MAX( dt_data_output_av, dt_3d ) )
1114       ENDIF
1115
1116!
1117!--    Output of particle time series
1118       IF ( particle_advection )  THEN
1119          IF ( time_dopts >= dt_dopts  .OR. &
1120               ( simulated_time >= particle_advection_start  .AND. &
1121                 first_call_lpm ) )  THEN
1122             CALL data_output_ptseries
1123             time_dopts = MOD( time_dopts, MAX( dt_dopts, dt_3d ) )
1124          ENDIF
1125       ENDIF
1126
1127!
1128!--    Output of dvrp-graphics (isosurface, particles, slicer)
1129#if defined( __dvrp_graphics )
1130       CALL DVRP_LOG_EVENT( -2, current_timestep_number-1 )
1131#endif
1132       IF ( time_dvrp >= dt_dvrp )  THEN
1133          CALL data_output_dvrp
1134          time_dvrp = MOD( time_dvrp, MAX( dt_dvrp, dt_3d ) )
1135       ENDIF
1136#if defined( __dvrp_graphics )
1137       CALL DVRP_LOG_EVENT( 2, current_timestep_number )
1138#endif
1139
1140!
1141!--    If required, set the heat flux for the next time step at a random value
1142       IF ( constant_heatflux  .AND.  random_heatflux )  CALL disturb_heatflux
1143
1144!
1145!--    Execute user-defined actions
1146       CALL user_actions( 'after_timestep' )
1147
1148!
1149!--    Output elapsed simulated time in form of a progress bar on stdout
1150!--    TO_DO: should be done by root domain later
1151#if ! defined( PMC_ACTIVE )
1152       IF ( myid == 0 )  CALL output_progress_bar
1153#endif
1154
1155       CALL cpu_log( log_point_s(10), 'timesteps', 'stop' )
1156
1157
1158    ENDDO   ! time loop
1159
1160!-- TO_DO: should be done by root domain later
1161#if ! defined( PMC_ACTIVE )
1162    IF ( myid == 0 )  CALL finish_progress_bar
1163#endif
1164
1165#if defined( __dvrp_graphics )
1166    CALL DVRP_LOG_EVENT( -2, current_timestep_number )
1167#endif
1168
1169    CALL location_message( 'finished time-stepping', .TRUE. )
1170
1171 END SUBROUTINE time_integration
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