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MODULE iceupdate
!!======================================================================
!! *** MODULE iceupdate ***
!! Sea-ice : computation of the flux at the sea ice/ocean interface
!!======================================================================
!! History : 4.0 ! 2018 (many people) SI3 [aka Sea Ice cube]
!!----------------------------------------------------------------------
#if defined key_si3
!!----------------------------------------------------------------------
!! 'key_si3' SI3 sea-ice model
!!----------------------------------------------------------------------
!! ice_update_alloc : allocate the iceupdate arrays
!! ice_update_init : initialisation
!! ice_update_flx : updates mass, heat and salt fluxes at the ocean surface
!! ice_update_tau : update i- and j-stresses, and its modulus at the ocean surface
!!----------------------------------------------------------------------
USE phycst ! physical constants
USE dom_oce ! ocean domain
USE ice ! sea-ice: variables
USE sbc_ice ! Surface boundary condition: ice fields
USE sbc_oce ! Surface boundary condition: ocean fields
USE sbccpl ! Surface boundary condition: coupled interface
USE icealb ! sea-ice: albedo parameters
USE traqsr ! add penetration of solar flux in the calculation of heat budget
USE icectl ! sea-ice: control prints
USE zdfdrg , ONLY : ln_drgice_imp
!
USE in_out_manager ! I/O manager
USE iom ! I/O manager library
USE lib_mpp ! MPP library
USE lib_fortran ! fortran utilities (glob_sum + no signed zero)
USE lbclnk ! lateral boundary conditions (or mpp links)
USE timing ! Timing
IMPLICIT NONE
PRIVATE
PUBLIC ice_update_init ! called by ice_init
PUBLIC ice_update_flx ! called by ice_stp
PUBLIC ice_update_tau ! called by ice_stp
REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: utau_oce, vtau_oce ! air-ocean surface i- & j-stress [N/m2]
REAL(wp), ALLOCATABLE, SAVE, DIMENSION(:,:) :: tmod_io ! modulus of the ice-ocean velocity [m/s]
!! * Substitutions
# include "do_loop_substitute.h90"
!!----------------------------------------------------------------------
!! NEMO/ICE 4.0 , NEMO Consortium (2018)
!! $Id: iceupdate.F90 15385 2021-10-15 13:52:48Z clem $
!! Software governed by the CeCILL license (see ./LICENSE)
!!----------------------------------------------------------------------
CONTAINS
INTEGER FUNCTION ice_update_alloc()
!!-------------------------------------------------------------------
!! *** ROUTINE ice_update_alloc ***
!!-------------------------------------------------------------------
ALLOCATE( utau_oce(jpi,jpj), vtau_oce(jpi,jpj), tmod_io(jpi,jpj), STAT=ice_update_alloc )
!
CALL mpp_sum( 'iceupdate', ice_update_alloc )
IF( ice_update_alloc /= 0 ) CALL ctl_stop( 'STOP', 'ice_update_alloc: failed to allocate arrays' )
!
END FUNCTION ice_update_alloc
SUBROUTINE ice_update_flx( kt )
!!-------------------------------------------------------------------
!! *** ROUTINE ice_update_flx ***
!!
!! ** Purpose : Update the surface ocean boundary condition for heat
!! salt and mass over areas where sea-ice is non-zero
!!
!! ** Action : - computes the heat and freshwater/salt fluxes
!! at the ice-ocean interface.
!! - Update the ocean sbc
!!
!! ** Outputs : - qsr : sea heat flux: solar
!! - qns : sea heat flux: non solar
!! - emp : freshwater budget: volume flux
!! - sfx : salt flux
!! - fr_i : ice fraction
!! - tn_ice : sea-ice surface temperature
!! - alb_ice : sea-ice albedo (recomputed only for coupled mode)
!!
!! References : Goosse, H. et al. 1996, Bul. Soc. Roy. Sc. Liege, 65, 87-90.
!! Tartinville et al. 2001 Ocean Modelling, 3, 95-108.
!! These refs are now obsolete since everything has been revised
!! The ref should be Rousset et al., 2015
!!---------------------------------------------------------------------
INTEGER, INTENT(in) :: kt ! number of iteration
!
INTEGER :: ji, jj, jl, jk ! dummy loop indices
REAL(wp) :: zqsr ! New solar flux received by the ocean
REAL(wp), ALLOCATABLE, DIMENSION(:,:) :: z2d ! 2D workspace
!!---------------------------------------------------------------------
IF( ln_timing ) CALL timing_start('iceupdate')
IF( kt == nit000 .AND. lwp ) THEN
WRITE(numout,*)
WRITE(numout,*)'ice_update_flx: update fluxes (mass, salt and heat) at the ice-ocean interface'
WRITE(numout,*)'~~~~~~~~~~~~~~'
ENDIF
! Net heat flux on top of the ice-ocean (W.m-2)
!----------------------------------------------
IF( ln_cndflx ) THEN ! ice-atm interface = conduction (and melting) fluxes
qt_atm_oi(:,:) = ( 1._wp - at_i_b(:,:) ) * ( qns_oce(:,:) + qsr_oce(:,:) ) + qemp_oce(:,:) + &
& SUM( a_i_b * ( qcn_ice + qml_ice + qtr_ice_top ), dim=3 ) + qemp_ice(:,:)
ELSE ! ice-atm interface = solar and non-solar fluxes
qt_atm_oi(:,:) = qns_tot(:,:) + qsr_tot(:,:)
ENDIF
! --- case we bypass ice thermodynamics --- !
IF( .NOT. ln_icethd ) THEN ! we suppose ice is impermeable => ocean is isolated from atmosphere
qt_atm_oi (:,:) = ( 1._wp - at_i_b(:,:) ) * ( qns_oce(:,:) + qsr_oce(:,:) ) + qemp_oce(:,:)
qt_oce_ai (:,:) = ( 1._wp - at_i_b(:,:) ) * qns_oce(:,:) + qemp_oce(:,:)
emp_ice (:,:) = 0._wp
qemp_ice (:,:) = 0._wp
qevap_ice (:,:,:) = 0._wp
ENDIF
DO_2D( nn_hls, nn_hls, nn_hls, nn_hls )
! Solar heat flux reaching the ocean (max) = zqsr (W.m-2)
!---------------------------------------------------
IF( ln_cndflx ) THEN ! ice-atm interface = conduction (and melting) fluxes
zqsr = ( 1._wp - at_i_b(ji,jj) ) * qsr_oce(ji,jj) + SUM( a_i_b (ji,jj,:) * qtr_ice_bot(ji,jj,:) )
ELSE ! ice-atm interface = solar and non-solar fluxes
zqsr = qsr_tot(ji,jj) - SUM( a_i_b(ji,jj,:) * ( qsr_ice(ji,jj,:) - qtr_ice_bot(ji,jj,:) ) )
ENDIF
! Total heat flux reaching the ocean = qt_oce_ai (W.m-2)
!---------------------------------------------------
IF( ln_icethd ) THEN
qt_oce_ai(ji,jj) = qt_atm_oi(ji,jj) - hfx_sum(ji,jj) - hfx_bom(ji,jj) - hfx_bog(ji,jj) &
& - hfx_dif(ji,jj) - hfx_opw(ji,jj) - hfx_snw(ji,jj) &
& + hfx_thd(ji,jj) + hfx_dyn(ji,jj) + hfx_res(ji,jj) &
& + hfx_sub(ji,jj) - SUM( qevap_ice(ji,jj,:) * a_i_b(ji,jj,:) ) + hfx_spr(ji,jj)
ENDIF
! New qsr and qns used to compute the oceanic heat flux at the next time step
!----------------------------------------------------------------------------
! if warming and some ice remains, then we suppose that the whole solar flux has been consumed to melt the ice
! else ( cooling or no ice left ), then we suppose that no solar flux has been consumed
!
IF( fhld(ji,jj) > 0._wp .AND. at_i(ji,jj) > 0._wp ) THEN !-- warming and some ice remains
! solar flux transmitted thru the 1st level of the ocean (i.e. not used by sea-ice)
qsr(ji,jj) = ( 1._wp - at_i_b(ji,jj) ) * qsr_oce(ji,jj) * ( 1._wp - frq_m(ji,jj) ) &
! + solar flux transmitted thru ice and the 1st ocean level (also not used by sea-ice)
& + SUM( a_i_b(ji,jj,:) * qtr_ice_bot(ji,jj,:) ) * ( 1._wp - frq_m(ji,jj) )
!
ELSE !-- cooling or no ice left
qsr(ji,jj) = zqsr
ENDIF
!
! the non-solar is simply derived from the solar flux
qns(ji,jj) = qt_oce_ai(ji,jj) - qsr(ji,jj)
! Mass flux at the atm. surface
!-----------------------------------
wfx_sub(ji,jj) = wfx_snw_sub(ji,jj) + wfx_ice_sub(ji,jj)
! Mass flux at the ocean surface
!------------------------------------
! ice-ocean mass flux
wfx_ice(ji,jj) = wfx_bog(ji,jj) + wfx_bom(ji,jj) + wfx_sum(ji,jj) + wfx_sni(ji,jj) &
& + wfx_opw(ji,jj) + wfx_dyn(ji,jj) + wfx_res(ji,jj) + wfx_lam(ji,jj)
! snw-ocean mass flux
wfx_snw(ji,jj) = wfx_snw_sni(ji,jj) + wfx_snw_dyn(ji,jj) + wfx_snw_sum(ji,jj)
! total mass flux at the ocean/ice interface
fmmflx(ji,jj) = - wfx_ice(ji,jj) - wfx_snw(ji,jj) - wfx_pnd(ji,jj) - wfx_err_sub(ji,jj) ! ice-ocean mass flux saved at least for biogeochemical model
emp (ji,jj) = emp_oce(ji,jj) - wfx_ice(ji,jj) - wfx_snw(ji,jj) - wfx_pnd(ji,jj) - wfx_err_sub(ji,jj) ! atm-ocean + ice-ocean mass flux
! Salt flux at the ocean surface
!------------------------------------------
sfx(ji,jj) = sfx_bog(ji,jj) + sfx_bom(ji,jj) + sfx_sum(ji,jj) + sfx_sni(ji,jj) + sfx_opw(ji,jj) &
& + sfx_res(ji,jj) + sfx_dyn(ji,jj) + sfx_bri(ji,jj) + sfx_sub(ji,jj) + sfx_lam(ji,jj)
! Mass of snow and ice per unit area
!----------------------------------------
snwice_mass_b(ji,jj) = snwice_mass(ji,jj) ! save mass from the previous ice time step
! ! new mass per unit area
snwice_mass (ji,jj) = tmask(ji,jj,1) * ( rhos * vt_s(ji,jj) + rhoi * vt_i(ji,jj) + rhow * (vt_ip(ji,jj) + vt_il(ji,jj)) )
! ! time evolution of snow+ice mass
snwice_fmass (ji,jj) = ( snwice_mass(ji,jj) - snwice_mass_b(ji,jj) ) * r1_Dt_ice
END_2D
! Storing the transmitted variables
!----------------------------------
fr_i (:,:) = at_i(:,:) ! Sea-ice fraction
tn_ice(:,:,:) = t_su(:,:,:) ! Ice surface temperature
! Snow/ice albedo (only if sent to coupler, useless in forced mode)
!------------------------------------------------------------------
CALL ice_alb( t_su, h_i, h_s, ln_pnd_alb, a_ip_eff, h_ip, cloud_fra, alb_ice ) ! ice albedo
!
IF( lrst_ice ) THEN !* write snwice_mass fields in the restart file
CALL update_rst( 'WRITE', kt )
ENDIF
!
! output all fluxes
!------------------
!
! --- salt fluxes [kg/m2/s] --- !
! ! sfxice = sfxbog + sfxbom + sfxsum + sfxsni + sfxopw + sfxres + sfxdyn + sfxbri + sfxsub + sfxlam
IF( iom_use('sfxice' ) ) CALL iom_put( 'sfxice', sfx * 1.e-03 ) ! salt flux from total ice growth/melt
IF( iom_use('sfxbog' ) ) CALL iom_put( 'sfxbog', sfx_bog * 1.e-03 ) ! salt flux from bottom growth
IF( iom_use('sfxbom' ) ) CALL iom_put( 'sfxbom', sfx_bom * 1.e-03 ) ! salt flux from bottom melting
IF( iom_use('sfxsum' ) ) CALL iom_put( 'sfxsum', sfx_sum * 1.e-03 ) ! salt flux from surface melting
IF( iom_use('sfxlam' ) ) CALL iom_put( 'sfxlam', sfx_lam * 1.e-03 ) ! salt flux from lateral melting
IF( iom_use('sfxsni' ) ) CALL iom_put( 'sfxsni', sfx_sni * 1.e-03 ) ! salt flux from snow ice formation
IF( iom_use('sfxopw' ) ) CALL iom_put( 'sfxopw', sfx_opw * 1.e-03 ) ! salt flux from open water formation
IF( iom_use('sfxdyn' ) ) CALL iom_put( 'sfxdyn', sfx_dyn * 1.e-03 ) ! salt flux from ridging rafting
IF( iom_use('sfxbri' ) ) CALL iom_put( 'sfxbri', sfx_bri * 1.e-03 ) ! salt flux from brines
IF( iom_use('sfxres' ) ) CALL iom_put( 'sfxres', sfx_res * 1.e-03 ) ! salt flux from undiagnosed processes
IF( iom_use('sfxsub' ) ) CALL iom_put( 'sfxsub', sfx_sub * 1.e-03 ) ! salt flux from sublimation
! --- mass fluxes [kg/m2/s] --- !
CALL iom_put( 'emp_oce', emp_oce ) ! emp over ocean (taking into account the snow blown away from the ice)
CALL iom_put( 'emp_ice', emp_ice ) ! emp over ice (taking into account the snow blown away from the ice)
! ! vfxice = vfxbog + vfxbom + vfxsum + vfxsni + vfxopw + vfxdyn + vfxres + vfxlam + vfxpnd
CALL iom_put( 'vfxice' , wfx_ice ) ! mass flux from total ice growth/melt
CALL iom_put( 'vfxbog' , wfx_bog ) ! mass flux from bottom growth
CALL iom_put( 'vfxbom' , wfx_bom ) ! mass flux from bottom melt
CALL iom_put( 'vfxsum' , wfx_sum ) ! mass flux from surface melt
CALL iom_put( 'vfxlam' , wfx_lam ) ! mass flux from lateral melt
CALL iom_put( 'vfxsni' , wfx_sni ) ! mass flux from snow-ice formation
CALL iom_put( 'vfxopw' , wfx_opw ) ! mass flux from growth in open water
CALL iom_put( 'vfxdyn' , wfx_dyn ) ! mass flux from dynamics (ridging)
CALL iom_put( 'vfxres' , wfx_res ) ! mass flux from undiagnosed processes
CALL iom_put( 'vfxpnd' , wfx_pnd ) ! mass flux from melt ponds
CALL iom_put( 'vfxsub' , wfx_ice_sub ) ! mass flux from ice sublimation (ice-atm.)
CALL iom_put( 'vfxsub_err', wfx_err_sub ) ! "excess" of sublimation sent to ocean
IF ( iom_use( 'vfxthin' ) ) THEN ! mass flux from ice growth in open water + thin ice (<20cm) => comparable to observations
ALLOCATE( z2d(jpi,jpj) )
WHERE( hm_i(:,:) < 0.2 .AND. hm_i(:,:) > 0. ) ; z2d = wfx_bog
ELSEWHERE ; z2d = 0._wp
END WHERE
CALL iom_put( 'vfxthin', wfx_opw + z2d )
DEALLOCATE( z2d )
ENDIF
! ! vfxsnw = vfxsnw_sni + vfxsnw_dyn + vfxsnw_sum
CALL iom_put( 'vfxsnw' , wfx_snw ) ! mass flux from total snow growth/melt
CALL iom_put( 'vfxsnw_sum' , wfx_snw_sum ) ! mass flux from snow melt at the surface
CALL iom_put( 'vfxsnw_sni' , wfx_snw_sni ) ! mass flux from snow melt during snow-ice formation
CALL iom_put( 'vfxsnw_dyn' , wfx_snw_dyn ) ! mass flux from dynamics (ridging)
CALL iom_put( 'vfxsnw_sub' , wfx_snw_sub ) ! mass flux from snow sublimation (ice-atm.)
CALL iom_put( 'vfxsnw_pre' , wfx_spr ) ! snow precip
! --- heat fluxes [W/m2] --- !
! ! qt_atm_oi - qt_oce_ai = hfxdhc - ( dihctrp + dshctrp )
IF( iom_use('qsr_oce' ) ) CALL iom_put( 'qsr_oce' , qsr_oce * ( 1._wp - at_i_b ) ) ! solar flux at ocean surface
IF( iom_use('qns_oce' ) ) CALL iom_put( 'qns_oce' , qns_oce * ( 1._wp - at_i_b ) + qemp_oce ) ! non-solar flux at ocean surface
IF( iom_use('qsr_ice' ) ) CALL iom_put( 'qsr_ice' , SUM( qsr_ice * a_i_b, dim=3 ) ) ! solar flux at ice surface
IF( iom_use('qns_ice' ) ) CALL iom_put( 'qns_ice' , SUM( qns_ice * a_i_b, dim=3 ) + qemp_ice ) ! non-solar flux at ice surface
IF( iom_use('qtr_ice_bot') ) CALL iom_put( 'qtr_ice_bot', SUM( qtr_ice_bot * a_i_b, dim=3 ) ) ! solar flux transmitted thru ice
IF( iom_use('qtr_ice_top') ) CALL iom_put( 'qtr_ice_top', SUM( qtr_ice_top * a_i_b, dim=3 ) ) ! solar flux transmitted thru ice surface
IF( iom_use('qt_oce' ) ) CALL iom_put( 'qt_oce' , ( qsr_oce + qns_oce ) * ( 1._wp - at_i_b ) + qemp_oce )
IF( iom_use('qt_ice' ) ) CALL iom_put( 'qt_ice' , SUM( ( qns_ice + qsr_ice ) * a_i_b, dim=3 ) + qemp_ice )
IF( iom_use('qt_oce_ai' ) ) CALL iom_put( 'qt_oce_ai' , qt_oce_ai * tmask(:,:,1) ) ! total heat flux at the ocean surface: interface oce-(ice+atm)
IF( iom_use('qt_atm_oi' ) ) CALL iom_put( 'qt_atm_oi' , qt_atm_oi * tmask(:,:,1) ) ! total heat flux at the oce-ice surface: interface atm-(ice+oce)
IF( iom_use('qemp_oce' ) ) CALL iom_put( 'qemp_oce' , qemp_oce ) ! Downward Heat Flux from E-P over ocean
IF( iom_use('qemp_ice' ) ) CALL iom_put( 'qemp_ice' , qemp_ice ) ! Downward Heat Flux from E-P over ice
! heat fluxes from ice transformations
! ! hfxdhc = hfxbog + hfxbom + hfxsum + hfxopw + hfxdif + hfxsnw - ( hfxthd + hfxdyn + hfxres + hfxsub + hfxspr )
CALL iom_put ('hfxbog' , hfx_bog ) ! heat flux used for ice bottom growth
CALL iom_put ('hfxbom' , hfx_bom ) ! heat flux used for ice bottom melt
CALL iom_put ('hfxsum' , hfx_sum ) ! heat flux used for ice surface melt
CALL iom_put ('hfxopw' , hfx_opw ) ! heat flux used for ice formation in open water
CALL iom_put ('hfxdif' , hfx_dif ) ! heat flux used for ice temperature change
CALL iom_put ('hfxsnw' , hfx_snw ) ! heat flux used for snow melt
CALL iom_put ('hfxerr' , hfx_err_dif ) ! heat flux error after heat diffusion
! heat fluxes associated with mass exchange (freeze/melt/precip...)
CALL iom_put ('hfxthd' , hfx_thd ) !
CALL iom_put ('hfxdyn' , hfx_dyn ) !
CALL iom_put ('hfxres' , hfx_res ) !
CALL iom_put ('hfxsub' , hfx_sub ) !
CALL iom_put ('hfxspr' , hfx_spr ) ! Heat flux from snow precip heat content
! other heat fluxes
IF( iom_use('hfxsensib' ) ) CALL iom_put( 'hfxsensib' , qsb_ice_bot * at_i_b ) ! Sensible oceanic heat flux
IF( iom_use('hfxcndbot' ) ) CALL iom_put( 'hfxcndbot' , SUM( qcn_ice_bot * a_i_b, dim=3 ) ) ! Bottom conduction flux
IF( iom_use('hfxcndtop' ) ) CALL iom_put( 'hfxcndtop' , SUM( qcn_ice_top * a_i_b, dim=3 ) ) ! Surface conduction flux
IF( iom_use('hfxmelt' ) ) CALL iom_put( 'hfxmelt' , SUM( qml_ice * a_i_b, dim=3 ) ) ! Surface melt flux
IF( iom_use('hfxldmelt' ) ) CALL iom_put( 'hfxldmelt' , fhld * at_i_b ) ! Heat in lead for ice melting
IF( iom_use('hfxldgrow' ) ) CALL iom_put( 'hfxldgrow' , qlead * r1_Dt_ice ) ! Heat in lead for ice growth
! controls
!---------
#if ! defined key_agrif
IF( ln_icediachk ) CALL ice_cons_final('iceupdate') ! conservation
#endif
IF( ln_icectl ) CALL ice_prt (kt, iiceprt, jiceprt, 3, 'Final state ice_update') ! prints
IF( sn_cfctl%l_prtctl ) CALL ice_prt3D ('iceupdate') ! prints
IF( ln_timing ) CALL timing_stop ('iceupdate') ! timing
!
END SUBROUTINE ice_update_flx
SUBROUTINE ice_update_tau( kt, pu_oce, pv_oce )
!!-------------------------------------------------------------------
!! *** ROUTINE ice_update_tau ***
!!
!! ** Purpose : Update the ocean surface stresses due to the ice
!!
!! ** Action : * at each ice time step (every nn_fsbc time step):
!! - compute the modulus of ice-ocean relative velocity
!! (*rho*Cd) at T-point (C-grid) or I-point (B-grid)
!! tmod_io = rhoco * | U_ice-U_oce |
!! - update the modulus of stress at ocean surface
!! taum = (1-a) * taum + a * tmod_io * | U_ice-U_oce |
!! * at each ocean time step (every kt):
!! compute linearized ice-ocean stresses as
!! Utau = tmod_io * | U_ice - pU_oce |
!! using instantaneous current ocean velocity (usually before)
!!
!! NB: - ice-ocean rotation angle no more allowed
!! - here we make an approximation: taum is only computed every ice time step
!! This avoids mutiple average to pass from T -> U,V grids and next from U,V grids
!! to T grid. taum is used in TKE and GLS, which should not be too sensitive to this approximaton...
!!
!! ** Outputs : - utau, vtau : surface ocean i- and j-stress (u- & v-pts) updated with ice-ocean fluxes
!! - taum : modulus of the surface ocean stress (T-point) updated with ice-ocean fluxes
!!---------------------------------------------------------------------
INTEGER , INTENT(in) :: kt ! ocean time-step index
REAL(wp), DIMENSION(jpi,jpj), INTENT(in) :: pu_oce, pv_oce ! surface ocean currents
!
INTEGER :: ji, jj ! dummy loop indices
REAL(wp) :: zat_u, zutau_ice, zu_t, zmodt ! local scalar
REAL(wp) :: zat_v, zvtau_ice, zv_t, zrhoco ! - -
REAL(wp) :: zflagi ! - -
!!---------------------------------------------------------------------
IF( ln_timing ) CALL timing_start('ice_update')
IF( kt == nit000 .AND. lwp ) THEN
WRITE(numout,*)
WRITE(numout,*)'ice_update_tau: update stress at the ice-ocean interface'
WRITE(numout,*)'~~~~~~~~~~~~~~'
ENDIF
zrhoco = rho0 * rn_cio
!
IF( MOD( kt-1, nn_fsbc ) == 0 ) THEN !== Ice time-step only ==! (i.e. surface module time-step)
DO_2D( 0, 0, 0, 0 ) !* update the modulus of stress at ocean surface (T-point)
! ! 2*(U_ice-U_oce) at T-point
zu_t = u_ice(ji,jj) + u_ice(ji-1,jj) - u_oce(ji,jj) - u_oce(ji-1,jj)
zv_t = v_ice(ji,jj) + v_ice(ji,jj-1) - v_oce(ji,jj) - v_oce(ji,jj-1)
! ! |U_ice-U_oce|^2
zmodt = 0.25_wp * ( zu_t * zu_t + zv_t * zv_t )
! ! update the ocean stress modulus
taum(ji,jj) = ( 1._wp - at_i(ji,jj) ) * taum(ji,jj) + at_i(ji,jj) * zrhoco * zmodt
tmod_io(ji,jj) = zrhoco * SQRT( zmodt ) ! rhoco * |U_ice-U_oce| at T-point
END_2D
CALL lbc_lnk( 'iceupdate', taum, 'T', 1.0_wp, tmod_io, 'T', 1.0_wp )
!
utau_oce(:,:) = utau(:,:) !* save the air-ocean stresses at ice time-step
vtau_oce(:,:) = vtau(:,:)
!
ENDIF
!
! !== every ocean time-step ==!
IF ( ln_drgice_imp ) THEN
! Save drag with right sign to update top drag in the ocean implicit friction
rCdU_ice(:,:) = -r1_rho0 * tmod_io(:,:) * at_i(:,:) * tmask(:,:,1)
zflagi = 0._wp
ELSE
zflagi = 1._wp
ENDIF
!
DO_2D( 0, 0, 0, 0 ) !* update the stress WITHOUT an ice-ocean rotation angle
! ice area at u and v-points
zat_u = ( at_i(ji,jj) * tmask(ji,jj,1) + at_i (ji+1,jj ) * tmask(ji+1,jj ,1) ) &
& / MAX( 1.0_wp , tmask(ji,jj,1) + tmask(ji+1,jj ,1) )
zat_v = ( at_i(ji,jj) * tmask(ji,jj,1) + at_i (ji ,jj+1 ) * tmask(ji ,jj+1,1) ) &
& / MAX( 1.0_wp , tmask(ji,jj,1) + tmask(ji ,jj+1,1) )
! ! linearized quadratic drag formulation
zutau_ice = 0.5_wp * ( tmod_io(ji,jj) + tmod_io(ji+1,jj) ) * ( u_ice(ji,jj) - pu_oce(ji,jj) )
zvtau_ice = 0.5_wp * ( tmod_io(ji,jj) + tmod_io(ji,jj+1) ) * ( v_ice(ji,jj) - pv_oce(ji,jj) )
! ! stresses at the ocean surface
utau(ji,jj) = ( 1._wp - zat_u ) * utau_oce(ji,jj) + zat_u * zutau_ice
vtau(ji,jj) = ( 1._wp - zat_v ) * vtau_oce(ji,jj) + zat_v * zvtau_ice
END_2D
CALL lbc_lnk( 'iceupdate', utau, 'U', -1.0_wp, vtau, 'V', -1.0_wp ) ! lateral boundary condition
!
IF( ln_timing ) CALL timing_stop('ice_update')
!
END SUBROUTINE ice_update_tau
SUBROUTINE ice_update_init
!!-------------------------------------------------------------------
!! *** ROUTINE ice_update_init ***
!!
!! ** Purpose : allocate ice-ocean stress fields and read restarts
!! containing the snow & ice mass
!!
!!-------------------------------------------------------------------
INTEGER :: ji, jj, jk ! dummy loop indices
REAL(wp) :: zcoefu, zcoefv, zcoeff ! local scalar
!!-------------------------------------------------------------------
!
IF(lwp) WRITE(numout,*)
IF(lwp) WRITE(numout,*) 'ice_update_init: ice-ocean stress init'
IF(lwp) WRITE(numout,*) '~~~~~~~~~~~~~~~'
!
! ! allocate ice_update array
IF( ice_update_alloc() /= 0 ) CALL ctl_stop( 'STOP', 'ice_update_init : unable to allocate standard arrays' )
!
CALL update_rst( 'READ' ) !* read or initialize all required files
!
END SUBROUTINE ice_update_init
SUBROUTINE update_rst( cdrw, kt )
!!---------------------------------------------------------------------
!! *** ROUTINE rhg_evp_rst ***
!!
!! ** Purpose : Read or write RHG file in restart file
!!
!! ** Method : use of IOM library
!!----------------------------------------------------------------------
CHARACTER(len=*) , INTENT(in) :: cdrw ! 'READ'/'WRITE' flag
INTEGER, OPTIONAL, INTENT(in) :: kt ! ice time-step
!
INTEGER :: iter ! local integer
INTEGER :: id1 ! local integer
!!----------------------------------------------------------------------
!
IF( TRIM(cdrw) == 'READ' ) THEN ! Read/initialize
! ! ---------------
IF( ln_rstart ) THEN !* Read the restart file
!
id1 = iom_varid( numrir, 'snwice_mass' , ldstop = .FALSE. )
!
IF( id1 > 0 ) THEN ! fields exist
CALL iom_get( numrir, jpdom_auto, 'snwice_mass' , snwice_mass )
CALL iom_get( numrir, jpdom_auto, 'snwice_mass_b', snwice_mass_b )
ELSE ! start from rest
IF(lwp) WRITE(numout,*) ' ==>> previous run without snow-ice mass output then set it'
snwice_mass (:,:) = tmask(:,:,1) * ( rhos * vt_s(:,:) + rhoi * vt_i(:,:) )
snwice_mass_b(:,:) = snwice_mass(:,:)
ENDIF
ELSE !* Start from rest
IF(lwp) WRITE(numout,*) ' ==>> start from rest: set the snow-ice mass'
snwice_mass (:,:) = tmask(:,:,1) * ( rhos * vt_s(:,:) + rhoi * vt_i(:,:) )
snwice_mass_b(:,:) = snwice_mass(:,:)
ENDIF
!
ELSEIF( TRIM(cdrw) == 'WRITE' ) THEN ! Create restart file
! ! -------------------
IF(lwp) WRITE(numout,*) '---- update-rst ----'
iter = kt + nn_fsbc - 1 ! ice restarts are written at kt == nitrst - nn_fsbc + 1
!
CALL iom_rstput( iter, nitrst, numriw, 'snwice_mass' , snwice_mass )
CALL iom_rstput( iter, nitrst, numriw, 'snwice_mass_b', snwice_mass_b )
!
ENDIF
!
END SUBROUTINE update_rst
#else
!!----------------------------------------------------------------------
!! Default option Dummy module NO SI3 sea-ice model
!!----------------------------------------------------------------------
#endif
!!======================================================================
END MODULE iceupdate