Skip to content
Snippets Groups Projects
sbcwave.F90 27.8 KiB
Newer Older
Guillaume Samson's avatar
Guillaume Samson committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533
MODULE sbcwave
   !!======================================================================
   !!                       ***  MODULE  sbcwave  ***
   !! Wave module
   !!======================================================================
   !! History :  3.3  !  2011-09  (M. Adani)  Original code: Drag Coefficient
   !!         :  3.4  !  2012-10  (M. Adani)  Stokes Drift
   !!            3.6  !  2014-09  (E. Clementi,P. Oddo) New Stokes Drift Computation
   !!             -   !  2016-12  (G. Madec, E. Clementi) update Stoke drift computation
   !!                                                    + add sbc_wave_ini routine
   !!            4.2  !  2020-12  (G. Madec, E. Clementi) updates, new Stoke drift computation
   !!                                                    according to Couvelard et al.,2019
   !!----------------------------------------------------------------------

   !!----------------------------------------------------------------------
   !!   sbc_stokes    : calculate 3D Stokes-drift velocities
   !!   sbc_wave      : wave data from wave model: forced (netcdf files) or coupled mode
   !!   sbc_wave_init : initialisation fo surface waves
   !!----------------------------------------------------------------------
   USE phycst         ! physical constants
   USE oce            ! ocean variables
   USE dom_oce        ! ocean domain variables
   USE sbc_oce        ! Surface boundary condition: ocean fields
   USE bdy_oce        ! open boundary condition variables
   USE domvvl         ! domain: variable volume layers
   USE zdf_oce,  ONLY : ln_zdfswm ! Qiao wave enhanced mixing 
   !
   USE iom            ! I/O manager library
   USE in_out_manager ! I/O manager
   USE lib_mpp        ! distribued memory computing library
   USE fldread        ! read input fields

   IMPLICIT NONE
   PRIVATE

   PUBLIC   sbc_stokes      ! routine called in sbccpl
   PUBLIC   sbc_wave        ! routine called in sbcmod
   PUBLIC   sbc_wave_init   ! routine called in sbcmod

   ! Variables checking if the wave parameters are coupled (if not, they are read from file)
   LOGICAL, PUBLIC ::   cpl_hsig          = .FALSE.
   LOGICAL, PUBLIC ::   cpl_phioc         = .FALSE.
   LOGICAL, PUBLIC ::   cpl_sdrftx        = .FALSE.
   LOGICAL, PUBLIC ::   cpl_sdrfty        = .FALSE.
   LOGICAL, PUBLIC ::   cpl_wper          = .FALSE.
   LOGICAL, PUBLIC ::   cpl_wnum          = .FALSE.
   LOGICAL, PUBLIC ::   cpl_wstrf         = .FALSE.
   LOGICAL, PUBLIC ::   cpl_wdrag         = .FALSE.
   LOGICAL, PUBLIC ::   cpl_charn         = .FALSE.
   LOGICAL, PUBLIC ::   cpl_taw           = .FALSE.
   LOGICAL, PUBLIC ::   cpl_bhd           = .FALSE.
   LOGICAL, PUBLIC ::   cpl_tusd          = .FALSE.
   LOGICAL, PUBLIC ::   cpl_tvsd          = .FALSE.

   INTEGER ::   jpfld    ! number of files to read for stokes drift
   INTEGER ::   jp_usd   ! index of stokes drift  (i-component) (m/s)    at T-point
   INTEGER ::   jp_vsd   ! index of stokes drift  (j-component) (m/s)    at T-point
   INTEGER ::   jp_hsw   ! index of significant wave hight      (m)      at T-point
   INTEGER ::   jp_wmp   ! index of mean wave period            (s)      at T-point

   TYPE(FLD), ALLOCATABLE, DIMENSION(:) ::   sf_cd      ! structure of input fields (file informations, fields read) Drag Coefficient
   TYPE(FLD), ALLOCATABLE, DIMENSION(:) ::   sf_sd      ! structure of input fields (file informations, fields read) Stokes Drift
   TYPE(FLD), ALLOCATABLE, DIMENSION(:) ::   sf_wn      ! structure of input fields (file informations, fields read) wave number for Qiao
   TYPE(FLD), ALLOCATABLE, DIMENSION(:) ::   sf_tauoc   ! structure of input fields (file informations, fields read) normalized wave stress into the ocean

   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   cdn_wave        !: Neutral drag coefficient at t-point
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   hsw             !: Significant Wave Height at t-point
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   wmp             !: Wave Mean Period at t-point
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   wnum            !: Wave Number at t-point
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   tauoc_wave      !: stress reduction factor  at t-point
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   tsd2d           !: Surface Stokes Drift module at t-point
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   div_sd          !: barotropic stokes drift divergence
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   ut0sd, vt0sd    !: surface Stokes drift velocities at t-point
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:,:) ::   usd, vsd, wsd   !: Stokes drift velocities at u-, v- & w-points, resp.u
!
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   charn           !: charnock coefficient at t-point
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   tawx            !: Net wave-supported stress, u
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   tawy            !: Net wave-supported stress, v
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   twox            !: wave-ocean momentum flux, u
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   twoy            !: wave-ocean momentum flux, v
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   tauoc_wavex     !: stress reduction factor  at, u component
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   tauoc_wavey     !: stress reduction factor  at, v component
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   phioc           !: tke flux from wave model
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   KZN2            !: Kz*N2
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   bhd_wave        !: Bernoulli head. wave induce pression
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:)   ::   tusd, tvsd      !: Stokes drift transport
   REAL(wp), PUBLIC, ALLOCATABLE, DIMENSION(:,:,:) ::   ZMX             !: Kz*N2
   !! * Substitutions
#  include "do_loop_substitute.h90"
#  include "domzgr_substitute.h90"
   !!----------------------------------------------------------------------
   !! NEMO/OCE 4.0 , NEMO Consortium (2018)
   !! $Id: sbcwave.F90 15199 2021-08-19 07:57:52Z amoulin $
   !! Software governed by the CeCILL license (see ./LICENSE)
   !!----------------------------------------------------------------------
CONTAINS

   SUBROUTINE sbc_stokes( Kmm )
      !!---------------------------------------------------------------------
      !!                     ***  ROUTINE sbc_stokes  ***
      !!
      !! ** Purpose :   compute the 3d Stokes Drift according to Breivik et al.,
      !!                2014 (DOI: 10.1175/JPO-D-14-0020.1)
      !!
      !! ** Method  : - Calculate the horizontal Stokes drift velocity (Breivik et al. 2014)
      !!              - Calculate its horizontal divergence
      !!              - Calculate the vertical Stokes drift velocity
      !!              - Calculate the barotropic Stokes drift divergence
      !!
      !! ** action  : - tsd2d         : module of the surface Stokes drift velocity
      !!              - usd, vsd, wsd : 3 components of the Stokes drift velocity
      !!              - div_sd        : barotropic Stokes drift divergence
      !!---------------------------------------------------------------------
      INTEGER, INTENT(in) :: Kmm ! ocean time level index
      INTEGER  ::   jj, ji, jk   ! dummy loop argument
      INTEGER  ::   ik           ! local integer
      REAL(wp) ::  ztransp, zfac, ztemp, zsp0, zsqrt, zbreiv16_w
      REAL(wp) ::  zdep_u, zdep_v, zkh_u, zkh_v, zda_u, zda_v, sdtrp
      REAL(wp), DIMENSION(:,:)  , ALLOCATABLE ::   zk_t, zk_u, zk_v, zu0_sd, zv0_sd ! 2D workspace
      REAL(wp), DIMENSION(:,:,:), ALLOCATABLE ::   ze3divh, zInt_w                  ! 3D workspace
      !!---------------------------------------------------------------------
      !
      ALLOCATE( ze3divh(jpi,jpj,jpkm1) ) ! jpkm1 -> avoid lbc_lnk on jpk that is not defined
      ALLOCATE( zInt_w(jpi,jpj,jpk) )
      ALLOCATE( zk_t(jpi,jpj), zk_u(jpi,jpj), zk_v(jpi,jpj), zu0_sd(jpi,jpj), zv0_sd(jpi,jpj) )
      zk_t    (:,:) = 0._wp
      zk_u    (:,:) = 0._wp
      zk_v    (:,:) = 0._wp
      zu0_sd  (:,:) = 0._wp
      zv0_sd  (:,:) = 0._wp
      ze3divh (:,:,:) = 0._wp

      !
      ! select parameterization for the calculation of vertical Stokes drift
      ! exp. wave number at t-point
      IF( ln_breivikFV_2016 ) THEN
      ! Assumptions :  ut0sd and vt0sd are surface Stokes drift at T-points
      !                sdtrp is the norm of Stokes transport
      !
         zfac = 0.166666666667_wp
         DO_2D( 1, 1, 1, 1 ) ! In the deep-water limit we have ke = ||ust0||/( 6 * ||transport|| )
            zsp0          = SQRT( ut0sd(ji,jj)*ut0sd(ji,jj) + vt0sd(ji,jj)*vt0sd(ji,jj) ) !<-- norm of Surface Stokes drift
            tsd2d(ji,jj)  = zsp0
            IF( cpl_tusd .AND. cpl_tvsd ) THEN  !stokes transport is provided in coupled mode
               sdtrp      = SQRT( tusd(ji,jj)*tusd(ji,jj) + tvsd(ji,jj)*tvsd(ji,jj) )  !<-- norm of Surface Stokes drift transport
            ELSE
               ! Stokes drift transport estimated from Hs and Tmean
               sdtrp      = 2.0_wp * rpi / 16.0_wp *                             &
                   &        hsw(ji,jj)*hsw(ji,jj) / MAX( wmp(ji,jj), 0.0000001_wp )
            ENDIF
            zk_t (ji,jj)  = zfac * zsp0 / MAX ( sdtrp, 0.0000001_wp ) !<-- ke = ||ust0||/( 6 * ||transport|| )
         END_2D
      !# define zInt_w ze3divh
         DO_3D( 1, 1, 1, 1, 1, jpk ) ! Compute the primitive of Breivik 2016 function at W-points
            zfac             = - 2._wp * zk_t (ji,jj) * gdepw(ji,jj,jk,Kmm)  !<-- zfac should be negative definite
            ztemp            = EXP ( zfac )
            zsqrt            = SQRT( -zfac )
            zbreiv16_w       = ztemp - SQRT(rpi)*zsqrt*ERFC(zsqrt) !Eq. 16 Breivik 2016
            zInt_w(ji,jj,jk) = ztemp - 4._wp * zk_t (ji,jj) * gdepw(ji,jj,jk,Kmm) * zbreiv16_w
         END_3D
!
         DO jk = 1, jpkm1
            zfac = 0.166666666667_wp
            DO_2D( 1, 1, 1, 1 ) !++ Compute the FV Breivik 2016 function at T-points
               zsp0          = zfac / MAX(zk_t (ji,jj),0.0000001_wp)
               ztemp         = zInt_w(ji,jj,jk) - zInt_w(ji,jj,jk+1)
               zu0_sd(ji,jj) = ut0sd(ji,jj) * zsp0 * ztemp * tmask(ji,jj,jk)
               zv0_sd(ji,jj) = vt0sd(ji,jj) * zsp0 * ztemp * tmask(ji,jj,jk)
            END_2D
            DO_2D( 1, 0, 1, 0 ) ! ++ Interpolate at U/V points
               zfac          =  1.0_wp / e3u(ji  ,jj,jk,Kmm)
               usd(ji,jj,jk) =  0.5_wp * zfac * ( zu0_sd(ji,jj)+zu0_sd(ji+1,jj) ) * umask(ji,jj,jk)
               zfac          =  1.0_wp / e3v(ji  ,jj,jk,Kmm)
               vsd(ji,jj,jk) =  0.5_wp * zfac * ( zv0_sd(ji,jj)+zv0_sd(ji,jj+1) ) * vmask(ji,jj,jk)
            END_2D
         ENDDO
      !# undef zInt_w
      !
      ELSE
         zfac = 2.0_wp * rpi / 16.0_wp
         DO_2D( 1, 1, 1, 1 )
            ! Stokes drift velocity estimated from Hs and Tmean
            ztransp = zfac * hsw(ji,jj)*hsw(ji,jj) / MAX( wmp(ji,jj), 0.0000001_wp )
            ! Stokes surface speed
            tsd2d(ji,jj) = SQRT( ut0sd(ji,jj)*ut0sd(ji,jj) + vt0sd(ji,jj)*vt0sd(ji,jj))
            ! Wavenumber scale
            zk_t(ji,jj) = ABS( tsd2d(ji,jj) ) / MAX( ABS( 5.97_wp*ztransp ), 0.0000001_wp )
         END_2D
         DO_2D( 1, 0, 1, 0 )          ! exp. wave number & Stokes drift velocity at u- & v-points
            zk_u(ji,jj) = 0.5_wp * ( zk_t(ji,jj) + zk_t(ji+1,jj) )
            zk_v(ji,jj) = 0.5_wp * ( zk_t(ji,jj) + zk_t(ji,jj+1) )
            !
            zu0_sd(ji,jj) = 0.5_wp * ( ut0sd(ji,jj) + ut0sd(ji+1,jj) )
            zv0_sd(ji,jj) = 0.5_wp * ( vt0sd(ji,jj) + vt0sd(ji,jj+1) )
         END_2D

      !                       !==  horizontal Stokes Drift 3D velocity  ==!

         DO_3D( 0, 0, 0, 0, 1, jpkm1 )
            zdep_u = 0.5_wp * ( gdept(ji,jj,jk,Kmm) + gdept(ji+1,jj,jk,Kmm) )
            zdep_v = 0.5_wp * ( gdept(ji,jj,jk,Kmm) + gdept(ji,jj+1,jk,Kmm) )
            !
            zkh_u = zk_u(ji,jj) * zdep_u     ! k * depth
            zkh_v = zk_v(ji,jj) * zdep_v
            !                                ! Depth attenuation
            zda_u = EXP( -2.0_wp*zkh_u ) / ( 1.0_wp + 8.0_wp*zkh_u )
            zda_v = EXP( -2.0_wp*zkh_v ) / ( 1.0_wp + 8.0_wp*zkh_v )
            !
            usd(ji,jj,jk) = zda_u * zu0_sd(ji,jj) * umask(ji,jj,jk)
            vsd(ji,jj,jk) = zda_v * zv0_sd(ji,jj) * vmask(ji,jj,jk)
         END_3D
      ENDIF

      CALL lbc_lnk( 'sbcwave', usd, 'U', -1.0_wp, vsd, 'V', -1.0_wp )

      !
      !                       !==  vertical Stokes Drift 3D velocity  ==!
      !
      DO_3D( 0, 1, 0, 1, 1, jpkm1 )    ! Horizontal e3*divergence
         ze3divh(ji,jj,jk) = (  e2u(ji  ,jj) * e3u(ji  ,jj,jk,Kmm) * usd(ji  ,jj,jk)    &
            &                 - e2u(ji-1,jj) * e3u(ji-1,jj,jk,Kmm) * usd(ji-1,jj,jk)    &
            &                 + e1v(ji,jj  ) * e3v(ji,jj  ,jk,Kmm) * vsd(ji,jj  ,jk)    &
            &                 - e1v(ji,jj-1) * e3v(ji,jj-1,jk,Kmm) * vsd(ji,jj-1,jk)  ) &
            &                * r1_e1e2t(ji,jj)
      END_3D
      !
      CALL lbc_lnk( 'sbcwave', ze3divh, 'T', 1.0_wp )
      !
      IF( ln_linssh ) THEN   ;   ik = 1   ! none zero velocity through the sea surface
      ELSE                   ;   ik = 2   ! w=0 at the surface (set one for all in sbc_wave_init)
      ENDIF
      DO jk = jpkm1, ik, -1          ! integrate from the bottom the hor. divergence (NB: at k=jpk w is always zero)
         wsd(:,:,jk) = wsd(:,:,jk+1) - ze3divh(:,:,jk)
      END DO
      !
      IF( ln_bdy ) THEN
         DO jk = 1, jpkm1
            wsd(:,:,jk) = wsd(:,:,jk) * bdytmask(:,:)
         END DO
      ENDIF
      !                       !==  Horizontal divergence of barotropic Stokes transport  ==!
      div_sd(:,:) = 0._wp
      DO jk = 1, jpkm1                                 !
        div_sd(:,:) = div_sd(:,:) + ze3divh(:,:,jk)
      END DO
      !
      CALL iom_put( "ustokes",  usd  )
      CALL iom_put( "vstokes",  vsd  )
      CALL iom_put( "wstokes",  wsd  )
!      !
      DEALLOCATE( ze3divh, zInt_w )
      DEALLOCATE( zk_t, zk_u, zk_v, zu0_sd, zv0_sd )
      !
   END SUBROUTINE sbc_stokes
!
!
   SUBROUTINE sbc_wave( kt, Kmm )
      !!---------------------------------------------------------------------
      !!                     ***  ROUTINE sbc_wave  ***
      !!
      !! ** Purpose :   read wave parameters from wave model in netcdf files
      !!                or from a coupled wave mdoel
      !!
      !!---------------------------------------------------------------------
      INTEGER, INTENT(in   ) ::   kt   ! ocean time step
      INTEGER, INTENT(in   ) ::   Kmm  ! ocean time index
      !!---------------------------------------------------------------------
      !
      IF( kt == nit000 .AND. lwp ) THEN
         WRITE(numout,*)
         WRITE(numout,*) 'sbc_wave : update the read waves fields'
         WRITE(numout,*) '~~~~~~~~ '
      ENDIF
      !
      IF( ln_cdgw .AND. .NOT. cpl_wdrag ) THEN     !==  Neutral drag coefficient  ==!
         CALL fld_read( kt, nn_fsbc, sf_cd )             ! read from external forcing
         cdn_wave(:,:) = sf_cd(1)%fnow(:,:,1) * tmask(:,:,1)
      ENDIF

      IF( ln_tauoc .AND. .NOT. cpl_wstrf ) THEN    !==  Wave induced stress  ==!
         CALL fld_read( kt, nn_fsbc, sf_tauoc )          ! read stress reduction factor due to wave from external forcing
         tauoc_wave(:,:) = sf_tauoc(1)%fnow(:,:,1) * tmask(:,:,1)
      ELSEIF ( ln_taw .AND. cpl_taw ) THEN
         IF (kt < 1) THEN ! The first fields gave by OASIS have very high erroneous values ....
            twox(:,:)=0._wp
            twoy(:,:)=0._wp
            tawx(:,:)=0._wp
            tawy(:,:)=0._wp
            tauoc_wavex(:,:) = 1._wp
            tauoc_wavey(:,:) = 1._wp
         ELSE
            tauoc_wavex(:,:) = abs(twox(:,:)/tawx(:,:))
            tauoc_wavey(:,:) = abs(twoy(:,:)/tawy(:,:))
         ENDIF
      ENDIF

      IF ( ln_phioc .and. cpl_phioc .and.  kt == nit000 ) THEN
         WRITE(numout,*)
         WRITE(numout,*) 'sbc_wave : PHIOC from wave model'
         WRITE(numout,*) '~~~~~~~~ '
      ENDIF

      IF( ln_sdw .AND. .NOT. cpl_sdrftx)  THEN       !==  Computation of the 3d Stokes Drift  ==!
         !
         IF( jpfld > 0 ) THEN                            ! Read from file only if the field is not coupled
            CALL fld_read( kt, nn_fsbc, sf_sd )          ! read wave parameters from external forcing
            !                                            ! NB: test case mode, not read as jpfld=0
            IF( jp_hsw > 0 )   hsw  (:,:) = sf_sd(jp_hsw)%fnow(:,:,1) * tmask(:,:,1)  ! significant wave height
            IF( jp_wmp > 0 )   wmp  (:,:) = sf_sd(jp_wmp)%fnow(:,:,1) * tmask(:,:,1)  ! wave mean period
            IF( jp_usd > 0 )   ut0sd(:,:) = sf_sd(jp_usd)%fnow(:,:,1) * tmask(:,:,1)  ! 2D zonal Stokes Drift at T point
            IF( jp_vsd > 0 )   vt0sd(:,:) = sf_sd(jp_vsd)%fnow(:,:,1) * tmask(:,:,1)  ! 2D meridional Stokes Drift at T point
         ENDIF

         ! Read also wave number if needed, so that it is available in
         ! coupling routines
         IF( ln_zdfswm .AND. .NOT. cpl_wnum ) THEN     !==wavenumber==!
            CALL fld_read( kt, nn_fsbc, sf_wn )             ! read wave parameters from external forcing
            wnum(:,:) = sf_wn(1)%fnow(:,:,1) * tmask(:,:,1)
         ENDIF
 
         !
         IF( jpfld == 4 .OR. ln_wave_test )   &
            &      CALL sbc_stokes( Kmm )                 ! Calculate only if all required fields are read
            !                                            ! or in wave test case
         !  !                                            ! In coupled case the call is done after (in sbc_cpl)
      ENDIF
         !
   END SUBROUTINE sbc_wave


   SUBROUTINE sbc_wave_init
      !!---------------------------------------------------------------------
      !!                     ***  ROUTINE sbc_wave_init  ***
      !!
      !! ** Purpose :   Initialisation fo surface waves
      !!
      !! ** Method  : - Read namelist namsbc_wave
      !!              - create the structure used to read required wave fields
      !!                (its size depends on namelist options)
      !! ** action
      !!---------------------------------------------------------------------
      INTEGER ::   ierror, ios   ! local integer
      INTEGER ::   ifpr
      !!
      CHARACTER(len=100)     ::  cn_dir                            ! Root directory for location of drag coefficient files
      TYPE(FLD_N), ALLOCATABLE, DIMENSION(:) ::   slf_i            ! array of namelist informations on the fields to read
      TYPE(FLD_N)            ::  sn_cdg, sn_usd, sn_vsd,  &
                             &   sn_hsw, sn_wmp, sn_wnum, sn_tauoc    ! informations about the fields to be read
      !
      NAMELIST/namsbc_wave/ cn_dir, sn_cdg, sn_usd, sn_vsd, sn_hsw, sn_wmp, sn_wnum, sn_tauoc,   &
         &                  ln_cdgw, ln_sdw, ln_tauoc, ln_stcor, ln_charn, ln_taw, ln_phioc,     &
         &                  ln_wave_test, ln_bern_srfc, ln_breivikFV_2016, ln_vortex_force, ln_stshear
      !!---------------------------------------------------------------------
      IF(lwp) THEN
         WRITE(numout,*)
         WRITE(numout,*) 'sbc_wave_init : surface waves in the system'
         WRITE(numout,*) '~~~~~~~~~~~~~ '
      ENDIF
      !
      READ  ( numnam_ref, namsbc_wave, IOSTAT = ios, ERR = 901)
901   IF( ios /= 0 )   CALL ctl_nam ( ios , 'namsbc_wave in reference namelist')

      READ  ( numnam_cfg, namsbc_wave, IOSTAT = ios, ERR = 902 )
902   IF( ios >  0 )   CALL ctl_nam ( ios , 'namsbc_wave in configuration namelist' )
      IF(lwm) WRITE ( numond, namsbc_wave )
      !
      IF(lwp) THEN
         WRITE(numout,*) '   Namelist namsbc_wave'
         WRITE(numout,*) '      Stokes drift                                  ln_sdw = ', ln_sdw
         WRITE(numout,*) '      Breivik 2016                       ln_breivikFV_2016 = ', ln_breivikFV_2016
         WRITE(numout,*) '      Stokes Coriolis & tracer advection terms    ln_stcor = ', ln_stcor
         WRITE(numout,*) '      Vortex Force                         ln_vortex_force = ', ln_vortex_force
         WRITE(numout,*) '      Bernouilli Head Pressure                ln_bern_srfc = ', ln_bern_srfc
         WRITE(numout,*) '      wave modified ocean stress                  ln_tauoc = ', ln_tauoc
         WRITE(numout,*) '      neutral drag coefficient (CORE bulk only)    ln_cdgw = ', ln_cdgw
         WRITE(numout,*) '      charnock coefficient                        ln_charn = ', ln_charn
         WRITE(numout,*) '      Stress modificated by wave                    ln_taw = ', ln_taw
         WRITE(numout,*) '      TKE flux from wave                          ln_phioc = ', ln_phioc
         WRITE(numout,*) '      Surface shear with Stokes drift           ln_stshear = ', ln_stshear
         WRITE(numout,*) '      Test with constant wave fields          ln_wave_test = ', ln_wave_test
      ENDIF

      !                                ! option check
      IF( .NOT.( ln_cdgw .OR. ln_sdw .OR. ln_tauoc .OR. ln_stcor .OR. ln_charn) )   &
         &     CALL ctl_warn( 'Ask for wave coupling but ln_cdgw=F, ln_sdw=F, ln_tauoc=F, ln_stcor=F')
      IF( ln_cdgw .AND. ln_blk )   &
         &     CALL ctl_stop( 'drag coefficient read from wave model NOT available yet with aerobulk package')
      IF( ln_stcor .AND. .NOT.ln_sdw )   &
         &     CALL ctl_stop( 'Stokes-Coriolis term calculated only if activated Stokes Drift ln_sdw=T')

      !                             !==  Allocate wave arrays  ==!
      ALLOCATE( ut0sd (jpi,jpj)    , vt0sd (jpi,jpj) )
      ALLOCATE( hsw   (jpi,jpj)    , wmp   (jpi,jpj) )
      ALLOCATE( wnum  (jpi,jpj) )
      ALLOCATE( tsd2d (jpi,jpj)    , div_sd(jpi,jpj)    , bhd_wave(jpi,jpj)     )
      ALLOCATE( usd   (jpi,jpj,jpk), vsd   (jpi,jpj,jpk), wsd     (jpi,jpj,jpk) )
      ALLOCATE( tusd  (jpi,jpj)    , tvsd  (jpi,jpj)    , ZMX     (jpi,jpj,jpk) )
      usd   (:,:,:) = 0._wp
      vsd   (:,:,:) = 0._wp
      wsd   (:,:,:) = 0._wp
      hsw     (:,:) = 0._wp
      wmp     (:,:) = 0._wp
      ut0sd   (:,:) = 0._wp
      vt0sd   (:,:) = 0._wp
      tusd    (:,:) = 0._wp
      tvsd    (:,:) = 0._wp
      bhd_wave(:,:) = 0._wp
      ZMX   (:,:,:) = 0._wp
!
      IF( ln_wave_test ) THEN       !==  Wave TEST case  ==!   set uniform waves fields
         jpfld    = 0                   ! No field read
         ln_cdgw  = .FALSE.             ! No neutral wave drag input
         ln_tauoc = .FALSE.             ! No wave induced drag reduction factor
         ut0sd(:,:) = 0.13_wp * tmask(:,:,1)   ! m/s
         vt0sd(:,:) = 0.00_wp                  ! m/s
         hsw  (:,:) = 2.80_wp                  ! meters
         wmp  (:,:) = 8.00_wp                  ! seconds
         !
      ELSE                          !==  create the structure associated with fields to be read  ==!
         IF( ln_cdgw ) THEN                       ! wave drag
            IF( .NOT. cpl_wdrag ) THEN
               ALLOCATE( sf_cd(1), STAT=ierror )               !* allocate and fill sf_wave with sn_cdg
               IF( ierror > 0 )   CALL ctl_stop( 'STOP', 'sbc_wave_init: unable to allocate sf_wave structure' )
               !
                                      ALLOCATE( sf_cd(1)%fnow(jpi,jpj,1)   )
               IF( sn_cdg%ln_tint )   ALLOCATE( sf_cd(1)%fdta(jpi,jpj,1,2) )
               CALL fld_fill( sf_cd, (/ sn_cdg /), cn_dir, 'sbc_wave_init', 'Wave module ', 'namsbc_wave' )
            ENDIF
            ALLOCATE( cdn_wave(jpi,jpj) )
            cdn_wave(:,:) = 0._wp
         ENDIF
         IF( ln_charn ) THEN                     ! wave drag
            IF( .NOT. cpl_charn ) THEN
               CALL ctl_stop( 'STOP', 'Charnock based wind stress can be used in coupled mode only' )
            ENDIF
            ALLOCATE( charn(jpi,jpj) )
            charn(:,:) = 0._wp
         ENDIF
         IF( ln_taw ) THEN                     ! wind stress
            IF( .NOT. cpl_taw ) THEN
               CALL ctl_stop( 'STOP', 'wind stress from wave model can be used in coupled mode only, use ln_cdgw instead' )
            ENDIF
            ALLOCATE( tawx(jpi,jpj) )
            ALLOCATE( tawy(jpi,jpj) )
            ALLOCATE( twox(jpi,jpj) )
            ALLOCATE( twoy(jpi,jpj) )
            ALLOCATE( tauoc_wavex(jpi,jpj) )
            ALLOCATE( tauoc_wavey(jpi,jpj) )
            tawx(:,:) = 0._wp
            tawy(:,:) = 0._wp
            twox(:,:) = 0._wp
            twoy(:,:) = 0._wp
            tauoc_wavex(:,:) = 1._wp
            tauoc_wavey(:,:) = 1._wp
         ENDIF

         IF( ln_phioc ) THEN                     ! TKE flux
            IF( .NOT. cpl_phioc ) THEN
                CALL ctl_stop( 'STOP', 'phioc can be used in coupled mode only' )
            ENDIF
            ALLOCATE( phioc(jpi,jpj) )
            phioc(:,:) = 0._wp
         ENDIF

         IF( ln_tauoc ) THEN                    ! normalized wave stress into the ocean
            IF( .NOT. cpl_wstrf ) THEN
               ALLOCATE( sf_tauoc(1), STAT=ierror )           !* allocate and fill sf_wave with sn_tauoc
               IF( ierror > 0 )   CALL ctl_stop( 'STOP', 'sbc_wave_init: unable to allocate sf_tauoc structure' )
               !
                                       ALLOCATE( sf_tauoc(1)%fnow(jpi,jpj,1)   )
               IF( sn_tauoc%ln_tint )  ALLOCATE( sf_tauoc(1)%fdta(jpi,jpj,1,2) )
               CALL fld_fill( sf_tauoc, (/ sn_tauoc /), cn_dir, 'sbc_wave_init', 'Wave module', 'namsbc_wave' )
            ENDIF
            ALLOCATE( tauoc_wave(jpi,jpj) )
            tauoc_wave(:,:) = 0._wp
         ENDIF

         IF( ln_sdw ) THEN                      ! Stokes drift
            ! 1. Find out how many fields have to be read from file if not coupled
            jpfld=0
            jp_usd=0   ;   jp_vsd=0   ;   jp_hsw=0   ;   jp_wmp=0
            IF( .NOT. cpl_sdrftx ) THEN
               jpfld  = jpfld + 1
               jp_usd = jpfld
            ENDIF
            IF( .NOT. cpl_sdrfty ) THEN
               jpfld  = jpfld + 1
               jp_vsd = jpfld
            ENDIF
            IF( .NOT. cpl_hsig ) THEN
               jpfld  = jpfld + 1
               jp_hsw = jpfld
            ENDIF
            IF( .NOT. cpl_wper ) THEN
               jpfld  = jpfld + 1
               jp_wmp = jpfld
            ENDIF
            ! 2. Read from file only the non-coupled fields
            IF( jpfld > 0 ) THEN
               ALLOCATE( slf_i(jpfld) )
               IF( jp_usd > 0 )   slf_i(jp_usd) = sn_usd
               IF( jp_vsd > 0 )   slf_i(jp_vsd) = sn_vsd
               IF( jp_hsw > 0 )   slf_i(jp_hsw) = sn_hsw
               IF( jp_wmp > 0 )   slf_i(jp_wmp) = sn_wmp
               ALLOCATE( sf_sd(jpfld), STAT=ierror )   !* allocate and fill sf_sd with stokes drift
               IF( ierror > 0 )   CALL ctl_stop( 'STOP', 'sbc_wave_init: unable to allocate sf_wave structure' )
               !
               DO ifpr= 1, jpfld
                  ALLOCATE( sf_sd(ifpr)%fnow(jpi,jpj,1) )
                  IF( slf_i(ifpr)%ln_tint )   ALLOCATE( sf_sd(ifpr)%fdta(jpi,jpj,1,2) )
               END DO
               !
               CALL fld_fill( sf_sd, slf_i, cn_dir, 'sbc_wave_init', 'Wave module ', 'namsbc_wave' )
               sf_sd(jp_usd)%zsgn = -1._wp   ;  sf_sd(jp_vsd)%zsgn = -1._wp   ! vector field at T point: overwrite default definition of zsgn
            ENDIF
            !
            ! 3. Wave number (only needed for Qiao parametrisation, ln_zdfswm=T)
            IF( .NOT. cpl_wnum ) THEN
               ALLOCATE( sf_wn(1), STAT=ierror )           !* allocate and fill sf_wave with sn_wnum
               IF( ierror > 0 )   CALL ctl_stop( 'STOP', 'sbc_wave_init: unable to allocate sf_wn structure' )
                                      ALLOCATE( sf_wn(1)%fnow(jpi,jpj,1)   )
               IF( sn_wnum%ln_tint )  ALLOCATE( sf_wn(1)%fdta(jpi,jpj,1,2) )
               CALL fld_fill( sf_wn, (/ sn_wnum /), cn_dir, 'sbc_wave', 'Wave module', 'namsbc_wave' )
            ENDIF
            !
         ENDIF
         !
      ENDIF
      !
   END SUBROUTINE sbc_wave_init

   !!======================================================================
END MODULE sbcwave