Changeset 15388


Ignore:
Timestamp:
2021-10-17T13:33:47+02:00 (3 months ago)
Author:
clem
Message:

slightly rearrange ice thermo. No change in sette

Location:
NEMO/trunk/src/ICE
Files:
5 edited

Legend:

Unmodified
Added
Removed
  • NEMO/trunk/src/ICE/ice.F90

    r15334 r15388  
    196196   !                                      !   = 0  Grenfell and Maykut 1977 (depends on cloudiness and is 0 when there is snow) 
    197197   !                                      !   = 1  Lebrun 2019 (equals 0.3 anytime with different melting/dry snw conductivities) 
     198 
     199   !                                     !!** namelist (namthd) ** 
     200   LOGICAL , PUBLIC ::   ln_icedH         ! activate ice thickness change from growing/melting (T) or not (F) 
     201   LOGICAL , PUBLIC ::   ln_icedA         ! activate lateral melting param. (T) or not (F) 
     202   LOGICAL , PUBLIC ::   ln_icedO         ! activate ice growth in open-water (T) or not (F) 
     203   LOGICAL , PUBLIC ::   ln_icedS         ! activate gravity drainage and flushing (T) or not (F) 
     204   LOGICAL , PUBLIC ::   ln_leadhfx       ! heat in the leads is used to melt sea-ice before warming the ocean 
     205   ! 
     206   !                                     !!** namelist (namthd_do) ** 
     207   REAL(wp), PUBLIC ::   rn_hinew         ! thickness for new ice formation (m) 
     208   LOGICAL , PUBLIC ::   ln_frazil        ! use of frazil ice collection as function of wind (T) or not (F) 
     209   REAL(wp), PUBLIC ::   rn_maxfraz       ! maximum portion of frazil ice collecting at the ice bottom 
     210   REAL(wp), PUBLIC ::   rn_vfraz         ! threshold drift speed for collection of bottom frazil ice 
     211   REAL(wp), PUBLIC ::   rn_Cfraz         ! squeezing coefficient for collection of bottom frazil ice 
    198212   ! 
    199213   !                                     !!** ice-vertical diffusion namelist (namthd_zdf) ** 
  • NEMO/trunk/src/ICE/icesbc.F90

    r14595 r15388  
    109109      !!                dqns_ice                                 = non solar  heat sensistivity                  [W/m2] 
    110110      !!                qemp_oce, qemp_ice, qprec_ice, qevap_ice = sensible heat (associated with evap & precip) [W/m2] 
     111      !!            + these fields 
     112      !!                qsb_ice_bot                              = sensible heat at the ice bottom               [W/m2] 
     113      !!                fhld, qlead                              = heat budget in the leads                      [W/m2] 
    111114      !!            + some fields that are not used outside this module: 
    112115      !!                qla_ice                                  = latent heat flux over ice                     [W/m2] 
     
    117120      INTEGER, INTENT(in) ::   kt     ! ocean time step 
    118121      INTEGER, INTENT(in) ::   ksbc   ! flux formulation (user defined, bulk or Pure Coupled) 
    119       ! 
    120       INTEGER  ::   ji, jj, jl      ! dummy loop index 
    121       REAL(wp) ::   zmiss_val       ! missing value retrieved from xios 
    122       REAL(wp), DIMENSION(:,:), ALLOCATABLE ::   zalb, zmsk00      ! 2D workspace 
    123122      !!-------------------------------------------------------------------- 
    124123      ! 
     
    130129         WRITE(numout,*)'~~~~~~~~~~~~~~~' 
    131130      ENDIF 
    132  
    133       ! get missing value from xml 
    134       CALL iom_miss_val( "icetemp", zmiss_val ) 
    135  
    136       ! --- ice albedo --- ! 
     131      !                     !== ice albedo ==! 
    137132      CALL ice_alb( t_su, h_i, h_s, ln_pnd_alb, a_ip_eff, h_ip, cloud_fra, alb_ice ) 
    138  
    139133      ! 
    140134      SELECT CASE( ksbc )   !== fluxes over sea ice ==! 
     
    142136      CASE( jp_usr )              !--- user defined formulation 
    143137                                  CALL usrdef_sbc_ice_flx( kt, h_s, h_i ) 
    144       CASE( jp_blk, jp_abl )  !--- bulk formulation & ABL formulation 
     138      CASE( jp_blk, jp_abl )      !--- bulk formulation & ABL formulation 
    145139                                  CALL blk_ice_2    ( t_su, h_s, h_i, alb_ice, & 
    146140            &                                         theta_air_zt(:,:), q_air_zt(:,:),    &   ! #LB: known from "sbc_oce" module... 
     
    156150         IF( nn_flxdist /= -1 )   CALL ice_flx_dist   ( t_su, alb_ice, qns_ice, qsr_ice, dqns_ice, evap_ice, devap_ice, nn_flxdist ) 
    157151      END SELECT 
    158  
    159       !--- output ice albedo and surface albedo ---! 
    160       IF( iom_use('icealb') .OR. iom_use('albedo') ) THEN 
    161  
    162          ALLOCATE( zalb(jpi,jpj), zmsk00(jpi,jpj) ) 
    163  
    164          WHERE( at_i_b < 1.e-03 ) 
    165             zmsk00(:,:) = 0._wp 
    166             zalb  (:,:) = rn_alb_oce 
    167          ELSEWHERE 
    168             zmsk00(:,:) = 1._wp 
    169             zalb  (:,:) = SUM( alb_ice * a_i_b, dim=3 ) / at_i_b 
    170          END WHERE 
    171          ! ice albedo 
    172          CALL iom_put( 'icealb' , zalb * zmsk00 + zmiss_val * ( 1._wp - zmsk00 ) ) 
    173          ! ice+ocean albedo 
    174          zalb(:,:) = SUM( alb_ice * a_i_b, dim=3 ) + rn_alb_oce * ( 1._wp - at_i_b ) 
    175          CALL iom_put( 'albedo' , zalb ) 
    176  
    177          DEALLOCATE( zalb, zmsk00 ) 
    178  
    179       ENDIF 
     152      !                     !== some fluxes at the ice-ocean interface and in the leads 
     153      CALL ice_flx_other 
    180154      ! 
    181155      IF( ln_timing )   CALL timing_stop('icesbc') 
     
    270244 
    271245 
     246   SUBROUTINE ice_flx_other 
     247      !!----------------------------------------------------------------------- 
     248      !!                   ***  ROUTINE ice_flx_other *** 
     249      !! 
     250      !! ** Purpose :   prepare necessary fields for thermo calculations 
     251      !! 
     252      !! ** Inputs  :   u_ice, v_ice, ssu_m, ssv_m, utau, vtau 
     253      !!                frq_m, qsr_oce, qns_oce, qemp_oce, e3t_m, sst_m 
     254      !! ** Outputs :   qsb_ice_bot, fhld, qlead 
     255      !!----------------------------------------------------------------------- 
     256      INTEGER  ::   ji, jj             ! dummy loop indices 
     257      REAL(wp) ::   zfric_u, zqld, zqfr, zqfr_neg, zqfr_pos, zu_io, zv_io, zu_iom1, zv_iom1 
     258      REAL(wp), PARAMETER ::   zfric_umin = 0._wp       ! lower bound for the friction velocity (cice value=5.e-04) 
     259      REAL(wp), PARAMETER ::   zch        = 0.0057_wp   ! heat transfer coefficient 
     260      REAL(wp), DIMENSION(jpi,jpj) ::  zfric, zvel      ! ice-ocean velocity (m/s) and frictional velocity (m2/s2) 
     261      !!----------------------------------------------------------------------- 
     262      ! 
     263      ! computation of friction velocity at T points 
     264      IF( ln_icedyn ) THEN 
     265         DO_2D( 0, 0, 0, 0 ) 
     266            zu_io   = u_ice(ji  ,jj  ) - ssu_m(ji  ,jj  ) 
     267            zu_iom1 = u_ice(ji-1,jj  ) - ssu_m(ji-1,jj  ) 
     268            zv_io   = v_ice(ji  ,jj  ) - ssv_m(ji  ,jj  ) 
     269            zv_iom1 = v_ice(ji  ,jj-1) - ssv_m(ji  ,jj-1) 
     270            ! 
     271            zfric(ji,jj) = rn_cio * ( 0.5_wp * ( zu_io*zu_io + zu_iom1*zu_iom1 + zv_io*zv_io + zv_iom1*zv_iom1 ) ) * tmask(ji,jj,1) 
     272            zvel (ji,jj) = 0.5_wp * SQRT( ( u_ice(ji-1,jj  ) + u_ice(ji,jj) ) * ( u_ice(ji-1,jj  ) + u_ice(ji,jj) ) + & 
     273               &                          ( v_ice(ji  ,jj-1) + v_ice(ji,jj) ) * ( v_ice(ji  ,jj-1) + v_ice(ji,jj) ) ) 
     274         END_2D 
     275      ELSE      !  if no ice dynamics => transfer directly the atmospheric stress to the ocean 
     276         DO_2D( 0, 0, 0, 0 ) 
     277            zfric(ji,jj) = r1_rho0 * SQRT( 0.5_wp *  & 
     278               &                         (  utau(ji,jj) * utau(ji,jj) + utau(ji-1,jj) * utau(ji-1,jj)   & 
     279               &                          + vtau(ji,jj) * vtau(ji,jj) + vtau(ji,jj-1) * vtau(ji,jj-1) ) ) * tmask(ji,jj,1) 
     280            zvel(ji,jj) = 0._wp 
     281         END_2D 
     282      ENDIF 
     283      CALL lbc_lnk( 'icesbc', zfric, 'T',  1.0_wp, zvel, 'T', 1.0_wp ) 
     284      ! 
     285      !--------------------------------------------------------------------! 
     286      ! Partial computation of forcing for the thermodynamic sea ice model 
     287      !--------------------------------------------------------------------! 
     288      DO_2D( nn_hls, nn_hls, nn_hls, nn_hls )   ! needed for qlead 
     289         rswitch  = tmask(ji,jj,1) * MAX( 0._wp , SIGN( 1._wp , at_i(ji,jj) - epsi10 ) ) ! 0 if no ice 
     290         ! 
     291         ! --- Energy received in the lead from atm-oce exchanges, zqld is defined everywhere (J.m-2) --- ! 
     292         zqld =  tmask(ji,jj,1) * rDt_ice *  & 
     293            &    ( ( 1._wp - at_i_b(ji,jj) ) * qsr_oce(ji,jj) * frq_m(ji,jj) +  & 
     294            &      ( 1._wp - at_i_b(ji,jj) ) * qns_oce(ji,jj) + qemp_oce(ji,jj) ) 
     295 
     296         ! --- Energy needed to bring ocean surface layer until its freezing, zqfr is defined everywhere (J.m-2) --- ! 
     297         !     (mostly<0 but >0 if supercooling) 
     298         zqfr     = rho0 * rcp * e3t_m(ji,jj) * ( t_bo(ji,jj) - ( sst_m(ji,jj) + rt0 ) ) * tmask(ji,jj,1)  ! both < 0 (t_bo < sst) and > 0 (t_bo > sst) 
     299         zqfr_neg = MIN( zqfr , 0._wp )                                                                    ! only < 0 
     300         zqfr_pos = MAX( zqfr , 0._wp )                                                                    ! only > 0 
     301 
     302         ! --- Sensible ocean-to-ice heat flux (W/m2) --- ! 
     303         !     (mostly>0 but <0 if supercooling) 
     304         zfric_u            = MAX( SQRT( zfric(ji,jj) ), zfric_umin ) 
     305         qsb_ice_bot(ji,jj) = rswitch * rho0 * rcp * zch * zfric_u * ( ( sst_m(ji,jj) + rt0 ) - t_bo(ji,jj) ) 
     306 
     307         ! upper bound for qsb_ice_bot: the heat retrieved from the ocean must be smaller than the heat necessary to reach 
     308         !                              the freezing point, so that we do not have SST < T_freeze 
     309         !                              This implies: qsb_ice_bot(ji,jj) * at_i(ji,jj) * rtdice <= - zqfr_neg 
     310         !                              The following formulation is ok for both normal conditions and supercooling 
     311         qsb_ice_bot(ji,jj) = rswitch * MIN( qsb_ice_bot(ji,jj), - zqfr_neg * r1_Dt_ice / MAX( at_i(ji,jj), epsi10 ) ) 
     312 
     313         ! If conditions are always supercooled (such as at the mouth of ice-shelves), then ice grows continuously 
     314         ! ==> stop ice formation by artificially setting up the turbulent fluxes to 0 when volume > 20m (arbitrary) 
     315         IF( ( t_bo(ji,jj) - ( sst_m(ji,jj) + rt0 ) ) > 0._wp .AND. vt_i(ji,jj) >= 20._wp ) THEN 
     316            zqfr               = 0._wp 
     317            zqfr_pos           = 0._wp 
     318            qsb_ice_bot(ji,jj) = 0._wp 
     319         ENDIF 
     320         ! 
     321         ! --- Energy Budget of the leads (qlead, J.m-2) --- ! 
     322         !     qlead is the energy received from the atm. in the leads. 
     323         !     If warming (zqld >= 0), then the energy in the leads is used to melt ice (bottom melting) => fhld  (W/m2) 
     324         !     If cooling (zqld <  0), then the energy in the leads is used to grow ice in open water    => qlead (J.m-2) 
     325         IF( zqld >= 0._wp .AND. at_i(ji,jj) > 0._wp ) THEN 
     326            ! upper bound for fhld: fhld should be equal to zqld 
     327            !                        but we have to make sure that this heat will not make the sst drop below the freezing point 
     328            !                        so the max heat that can be pulled out of the ocean is zqld - qsb - zqfr_pos 
     329            !                        The following formulation is ok for both normal conditions and supercooling 
     330            fhld (ji,jj) = rswitch * MAX( 0._wp, ( zqld - zqfr_pos ) * r1_Dt_ice / MAX( at_i(ji,jj), epsi10 ) &  ! divided by at_i since this is (re)multiplied by a_i in icethd_dh.F90 
     331               &                                 - qsb_ice_bot(ji,jj) ) 
     332            qlead(ji,jj) = 0._wp 
     333         ELSE 
     334            fhld (ji,jj) = 0._wp 
     335            ! upper bound for qlead: qlead should be equal to zqld 
     336            !                        but before using this heat for ice formation, we suppose that the ocean cools down till the freezing point. 
     337            !                        The energy for this cooling down is zqfr. Also some heat will be removed from the ocean from turbulent fluxes (qsb) 
     338            !                        and freezing point is reached if zqfr = zqld - qsb*a/dt 
     339            !                        so the max heat that can be pulled out of the ocean is zqld - qsb - zqfr 
     340            !                        The following formulation is ok for both normal conditions and supercooling 
     341            qlead(ji,jj) = MIN( 0._wp , zqld - ( qsb_ice_bot(ji,jj) * at_i(ji,jj) * rDt_ice ) - zqfr ) 
     342         ENDIF 
     343         ! 
     344         ! If ice is landfast and ice concentration reaches its max 
     345         ! => stop ice formation in open water 
     346         IF(  zvel(ji,jj) <= 5.e-04_wp .AND. at_i(ji,jj) >= rn_amax_2d(ji,jj)-epsi06 )   qlead(ji,jj) = 0._wp 
     347         ! 
     348         ! If the grid cell is almost fully covered by ice (no leads) 
     349         ! => stop ice formation in open water 
     350         IF( at_i(ji,jj) >= (1._wp - epsi10) )   qlead(ji,jj) = 0._wp 
     351         ! 
     352         ! If ln_leadhfx is false 
     353         ! => do not use energy of the leads to melt sea-ice 
     354         IF( .NOT.ln_leadhfx )   fhld(ji,jj) = 0._wp 
     355         ! 
     356      END_2D 
     357 
     358      ! In case we bypass open-water ice formation 
     359      IF( .NOT. ln_icedO )  qlead(:,:) = 0._wp 
     360      ! In case we bypass growing/melting from top and bottom 
     361      IF( .NOT. ln_icedH ) THEN 
     362         qsb_ice_bot(:,:) = 0._wp 
     363         fhld       (:,:) = 0._wp 
     364      ENDIF 
     365       
     366   END SUBROUTINE ice_flx_other 
     367    
     368    
    272369   SUBROUTINE ice_sbc_init 
    273370      !!------------------------------------------------------------------- 
  • NEMO/trunk/src/ICE/icethd.F90

    r15385 r15388  
    2020   USE sbc_oce , ONLY : sss_m, sst_m, e3t_m, utau, vtau, ssu_m, ssv_m, frq_m, sprecip, ln_cpl 
    2121   USE sbc_ice , ONLY : qsr_oce, qns_oce, qemp_oce, qsr_ice, qns_ice, dqns_ice, evap_ice, qprec_ice, qevap_ice, & 
    22       &                 qml_ice, qcn_ice, qtr_ice_top, utau_ice, vtau_ice 
     22      &                 qml_ice, qcn_ice, qtr_ice_top 
    2323   USE ice1D          ! sea-ice: thermodynamics variables 
    2424   USE icethd_zdf     ! sea-ice: vertical heat diffusion 
     
    4848   PUBLIC   ice_thd_init    ! called by ice_init 
    4949 
    50    !!** namelist (namthd) ** 
    51    LOGICAL ::   ln_icedH         ! activate ice thickness change from growing/melting (T) or not (F) 
    52    LOGICAL ::   ln_icedA         ! activate lateral melting param. (T) or not (F) 
    53    LOGICAL ::   ln_icedO         ! activate ice growth in open-water (T) or not (F) 
    54    LOGICAL ::   ln_icedS         ! activate gravity drainage and flushing (T) or not (F) 
    55    LOGICAL ::   ln_leadhfx       ! heat in the leads is used to melt sea-ice before warming the ocean 
    56  
    5750   !! for convergence tests 
    5851   REAL(wp), ALLOCATABLE, DIMENSION(:,:,:) ::   ztice_cvgerr, ztice_cvgstp 
     
    109102         ztice_cvgerr = 0._wp ; ztice_cvgstp = 0._wp 
    110103      ENDIF 
    111  
    112       ! --- calculate (some) heat fluxes and frazil ice --- ! 
    113       ! out => sensible heat (qsb_ice_bot) & heat budget in the leads (fhld & qlead) 
    114       ! out => ice collection thickness (ht_i_new) and fraction of frazil (fraz_frac) 
    115       CALL thd_prep 
    116        
     104      ! 
     105      CALL ice_thd_frazil             !--- frazil ice: collection thickness (ht_i_new) & fraction of frazil (fraz_frac) 
     106      ! 
    117107      !-------------------------------------------------------------------------------------------! 
    118108      ! Thermodynamic computation (only on grid points covered by ice) => loop over ice categories 
     
    260250      ! 
    261251   END SUBROUTINE ice_thd_mono 
    262  
    263    SUBROUTINE thd_prep 
    264       !!----------------------------------------------------------------------- 
    265       !!                   ***  ROUTINE thd_prep *** 
    266       !! 
    267       !! ** Purpose :   prepare necessary fields for thermo calculations 
    268       !! 
    269       !! For the fluxes 
    270       !! ** Inputs  :   u_ice, v_ice, ssu_m, ssv_m, utau, vtau 
    271       !!                frq_m, qsr_oce, qns_oce, qemp_oce, e3t_m, sst_m 
    272       !! ** Outputs :   qsb_ice_bot, fhld, qlead 
    273       !! 
    274       !! For the collection thickness (frazil) 
    275       !! ** Inputs  :   u_ice, v_ice, utau_ice, vtau_ice 
    276       !! ** Ouputs  :   ht_i_new, fraz_frac 
    277       !!----------------------------------------------------------------------- 
    278       INTEGER  ::   ji, jj             ! dummy loop indices 
    279       REAL(wp) ::   zfric_u, zqld, zqfr, zqfr_neg, zqfr_pos, zu_io, zv_io, zu_iom1, zv_iom1 
    280       REAL(wp), PARAMETER ::   zfric_umin = 0._wp       ! lower bound for the friction velocity (cice value=5.e-04) 
    281       REAL(wp), PARAMETER ::   zch        = 0.0057_wp   ! heat transfer coefficient 
    282       REAL(wp), DIMENSION(jpi,jpj) ::  zfric, zvel      ! ice-ocean velocity (m/s) and frictional velocity (m2/s2) 
    283       ! 
    284       ! for frazil ice 
    285       INTEGER  ::   iter 
    286       REAL(wp) ::   zvfrx, zvgx, ztaux, zf, ztenagm, zvfry, zvgy, ztauy, zvrel2, zfp, ztwogp 
    287       REAL(wp), PARAMETER ::   zcai    = 1.4e-3_wp                       ! ice-air drag (clem: should be dependent on coupling/forcing used) 
    288       REAL(wp), PARAMETER ::   zhicrit = 0.04_wp                         ! frazil ice thickness 
    289       REAL(wp), PARAMETER ::   zsqcd   = 1.0_wp / SQRT( 1.3_wp * zcai )  ! 1/SQRT(airdensity*drag) 
    290       REAL(wp), PARAMETER ::   zgamafr = 0.03_wp 
    291       !!----------------------------------------------------------------------- 
    292       ! 
    293       ! computation of friction velocity at T points 
    294       IF( ln_icedyn ) THEN 
    295          DO_2D( 0, 0, 0, 0 ) 
    296             zu_io   = u_ice(ji  ,jj  ) - ssu_m(ji  ,jj  ) 
    297             zu_iom1 = u_ice(ji-1,jj  ) - ssu_m(ji-1,jj  ) 
    298             zv_io   = v_ice(ji  ,jj  ) - ssv_m(ji  ,jj  ) 
    299             zv_iom1 = v_ice(ji  ,jj-1) - ssv_m(ji  ,jj-1) 
    300             ! 
    301             zfric(ji,jj) = rn_cio * ( 0.5_wp * ( zu_io*zu_io + zu_iom1*zu_iom1 + zv_io*zv_io + zv_iom1*zv_iom1 ) ) * tmask(ji,jj,1) 
    302             zvel (ji,jj) = 0.5_wp * SQRT( ( u_ice(ji-1,jj  ) + u_ice(ji,jj) ) * ( u_ice(ji-1,jj  ) + u_ice(ji,jj) ) + & 
    303                &                          ( v_ice(ji  ,jj-1) + v_ice(ji,jj) ) * ( v_ice(ji  ,jj-1) + v_ice(ji,jj) ) ) 
    304          END_2D 
    305       ELSE      !  if no ice dynamics => transfer directly the atmospheric stress to the ocean 
    306          DO_2D( 0, 0, 0, 0 ) 
    307             zfric(ji,jj) = r1_rho0 * SQRT( 0.5_wp *  & 
    308                &                         (  utau(ji,jj) * utau(ji,jj) + utau(ji-1,jj) * utau(ji-1,jj)   & 
    309                &                          + vtau(ji,jj) * vtau(ji,jj) + vtau(ji,jj-1) * vtau(ji,jj-1) ) ) * tmask(ji,jj,1) 
    310             zvel(ji,jj) = 0._wp 
    311          END_2D 
    312       ENDIF 
    313       CALL lbc_lnk( 'icethd', zfric, 'T',  1.0_wp, zvel, 'T', 1.0_wp ) 
    314       ! 
    315       !--------------------------------------------------------------------! 
    316       ! Partial computation of forcing for the thermodynamic sea ice model 
    317       !--------------------------------------------------------------------! 
    318       DO_2D( nn_hls, nn_hls, nn_hls, nn_hls )   ! needed for qlead 
    319          rswitch  = tmask(ji,jj,1) * MAX( 0._wp , SIGN( 1._wp , at_i(ji,jj) - epsi10 ) ) ! 0 if no ice 
    320          ! 
    321          ! --- Energy received in the lead from atm-oce exchanges, zqld is defined everywhere (J.m-2) --- ! 
    322          zqld =  tmask(ji,jj,1) * rDt_ice *  & 
    323             &    ( ( 1._wp - at_i_b(ji,jj) ) * qsr_oce(ji,jj) * frq_m(ji,jj) +  & 
    324             &      ( 1._wp - at_i_b(ji,jj) ) * qns_oce(ji,jj) + qemp_oce(ji,jj) ) 
    325  
    326          ! --- Energy needed to bring ocean surface layer until its freezing, zqfr is defined everywhere (J.m-2) --- ! 
    327          !     (mostly<0 but >0 if supercooling) 
    328          zqfr     = rho0 * rcp * e3t_m(ji,jj) * ( t_bo(ji,jj) - ( sst_m(ji,jj) + rt0 ) ) * tmask(ji,jj,1)  ! both < 0 (t_bo < sst) and > 0 (t_bo > sst) 
    329          zqfr_neg = MIN( zqfr , 0._wp )                                                                    ! only < 0 
    330          zqfr_pos = MAX( zqfr , 0._wp )                                                                    ! only > 0 
    331  
    332          ! --- Sensible ocean-to-ice heat flux (W/m2) --- ! 
    333          !     (mostly>0 but <0 if supercooling) 
    334          zfric_u            = MAX( SQRT( zfric(ji,jj) ), zfric_umin ) 
    335          qsb_ice_bot(ji,jj) = rswitch * rho0 * rcp * zch * zfric_u * ( ( sst_m(ji,jj) + rt0 ) - t_bo(ji,jj) ) 
    336  
    337          ! upper bound for qsb_ice_bot: the heat retrieved from the ocean must be smaller than the heat necessary to reach 
    338          !                              the freezing point, so that we do not have SST < T_freeze 
    339          !                              This implies: qsb_ice_bot(ji,jj) * at_i(ji,jj) * rtdice <= - zqfr_neg 
    340          !                              The following formulation is ok for both normal conditions and supercooling 
    341          qsb_ice_bot(ji,jj) = rswitch * MIN( qsb_ice_bot(ji,jj), - zqfr_neg * r1_Dt_ice / MAX( at_i(ji,jj), epsi10 ) ) 
    342  
    343          ! If conditions are always supercooled (such as at the mouth of ice-shelves), then ice grows continuously 
    344          ! ==> stop ice formation by artificially setting up the turbulent fluxes to 0 when volume > 20m (arbitrary) 
    345          IF( ( t_bo(ji,jj) - ( sst_m(ji,jj) + rt0 ) ) > 0._wp .AND. vt_i(ji,jj) >= 20._wp ) THEN 
    346             zqfr               = 0._wp 
    347             zqfr_pos           = 0._wp 
    348             qsb_ice_bot(ji,jj) = 0._wp 
    349          ENDIF 
    350          ! 
    351          ! --- Energy Budget of the leads (qlead, J.m-2) --- ! 
    352          !     qlead is the energy received from the atm. in the leads. 
    353          !     If warming (zqld >= 0), then the energy in the leads is used to melt ice (bottom melting) => fhld  (W/m2) 
    354          !     If cooling (zqld <  0), then the energy in the leads is used to grow ice in open water    => qlead (J.m-2) 
    355          IF( zqld >= 0._wp .AND. at_i(ji,jj) > 0._wp ) THEN 
    356             ! upper bound for fhld: fhld should be equal to zqld 
    357             !                        but we have to make sure that this heat will not make the sst drop below the freezing point 
    358             !                        so the max heat that can be pulled out of the ocean is zqld - qsb - zqfr_pos 
    359             !                        The following formulation is ok for both normal conditions and supercooling 
    360             fhld (ji,jj) = rswitch * MAX( 0._wp, ( zqld - zqfr_pos ) * r1_Dt_ice / MAX( at_i(ji,jj), epsi10 ) &  ! divided by at_i since this is (re)multiplied by a_i in icethd_dh.F90 
    361                &                                 - qsb_ice_bot(ji,jj) ) 
    362             qlead(ji,jj) = 0._wp 
    363          ELSE 
    364             fhld (ji,jj) = 0._wp 
    365             ! upper bound for qlead: qlead should be equal to zqld 
    366             !                        but before using this heat for ice formation, we suppose that the ocean cools down till the freezing point. 
    367             !                        The energy for this cooling down is zqfr. Also some heat will be removed from the ocean from turbulent fluxes (qsb) 
    368             !                        and freezing point is reached if zqfr = zqld - qsb*a/dt 
    369             !                        so the max heat that can be pulled out of the ocean is zqld - qsb - zqfr 
    370             !                        The following formulation is ok for both normal conditions and supercooling 
    371             qlead(ji,jj) = MIN( 0._wp , zqld - ( qsb_ice_bot(ji,jj) * at_i(ji,jj) * rDt_ice ) - zqfr ) 
    372          ENDIF 
    373          ! 
    374          ! If ice is landfast and ice concentration reaches its max 
    375          ! => stop ice formation in open water 
    376          IF(  zvel(ji,jj) <= 5.e-04_wp .AND. at_i(ji,jj) >= rn_amax_2d(ji,jj)-epsi06 )   qlead(ji,jj) = 0._wp 
    377          ! 
    378          ! If the grid cell is almost fully covered by ice (no leads) 
    379          ! => stop ice formation in open water 
    380          IF( at_i(ji,jj) >= (1._wp - epsi10) )   qlead(ji,jj) = 0._wp 
    381          ! 
    382          ! If ln_leadhfx is false 
    383          ! => do not use energy of the leads to melt sea-ice 
    384          IF( .NOT.ln_leadhfx )   fhld(ji,jj) = 0._wp 
    385          ! 
    386       END_2D 
    387  
    388       ! In case we bypass open-water ice formation 
    389       IF( .NOT. ln_icedO )  qlead(:,:) = 0._wp 
    390       ! In case we bypass growing/melting from top and bottom 
    391       IF( .NOT. ln_icedH ) THEN 
    392          qsb_ice_bot(:,:) = 0._wp 
    393          fhld       (:,:) = 0._wp 
    394       ENDIF 
    395  
    396       !---------------------------------------------------------! 
    397       ! Collection thickness of ice formed in leads and polynyas 
    398       !---------------------------------------------------------!     
    399       ! ht_i_new is the thickness of new ice formed in open water 
    400       ! ht_i_new can be either prescribed (ln_frazil=F) or computed (ln_frazil=T) 
    401       ! Frazil ice forms in open water, is transported by wind, accumulates at the edge of the consolidated ice edge 
    402       ! where it forms aggregates of a specific thickness called collection thickness. 
    403       ! 
    404       fraz_frac(:,:) = 0._wp 
    405       ! 
    406       ! Default new ice thickness 
    407       WHERE( qlead(:,:) < 0._wp ) ! cooling 
    408          ht_i_new(:,:) = rn_hinew 
    409       ELSEWHERE 
    410          ht_i_new(:,:) = 0._wp 
    411       END WHERE 
    412  
    413       IF( ln_frazil ) THEN 
    414          ztwogp  = 2._wp * rho0 / ( grav * 0.3_wp * ( rho0 - rhoi ) )  ! reduced grav 
    415          ! 
    416          DO_2D( 0, 0, 0, 0 ) 
    417             IF ( qlead(ji,jj) < 0._wp ) THEN ! cooling 
    418                ! -- Wind stress -- ! 
    419                ztaux = ( utau_ice(ji-1,jj  ) * umask(ji-1,jj  ,1) + utau_ice(ji,jj) * umask(ji,jj,1) ) * 0.5_wp 
    420                ztauy = ( vtau_ice(ji  ,jj-1) * vmask(ji  ,jj-1,1) + vtau_ice(ji,jj) * vmask(ji,jj,1) ) * 0.5_wp 
    421                ! Square root of wind stress 
    422                ztenagm = SQRT( SQRT( ztaux * ztaux + ztauy * ztauy ) ) 
    423  
    424                ! -- Frazil ice velocity -- ! 
    425                rswitch = MAX( 0._wp, SIGN( 1._wp , ztenagm - epsi10 ) ) 
    426                zvfrx   = rswitch * zgamafr * zsqcd * ztaux / MAX( ztenagm, epsi10 ) 
    427                zvfry   = rswitch * zgamafr * zsqcd * ztauy / MAX( ztenagm, epsi10 ) 
    428  
    429                ! -- Pack ice velocity -- ! 
    430                zvgx    = ( u_ice(ji-1,jj  ) * umask(ji-1,jj  ,1)  + u_ice(ji,jj) * umask(ji,jj,1) ) * 0.5_wp 
    431                zvgy    = ( v_ice(ji  ,jj-1) * vmask(ji  ,jj-1,1)  + v_ice(ji,jj) * vmask(ji,jj,1) ) * 0.5_wp 
    432  
    433                ! -- Relative frazil/pack ice velocity -- ! 
    434                rswitch = MAX( 0._wp, SIGN( 1._wp , at_i(ji,jj) - epsi10 ) ) 
    435                zvrel2  = MAX( (zvfrx - zvgx)*(zvfrx - zvgx) + (zvfry - zvgy)*(zvfry - zvgy), 0.15_wp*0.15_wp ) * rswitch 
    436  
    437                ! -- fraction of frazil ice -- ! 
    438                fraz_frac(ji,jj) = rswitch * ( TANH( rn_Cfraz * ( SQRT(zvrel2) - rn_vfraz ) ) + 1._wp ) * 0.5_wp * rn_maxfraz 
    439                 
    440                ! -- new ice thickness (iterative loop) -- ! 
    441                ht_i_new(ji,jj) = zhicrit +   ( zhicrit + 0.1_wp )    & 
    442                   &                      / ( ( zhicrit + 0.1_wp ) * ( zhicrit + 0.1_wp ) -  zhicrit * zhicrit ) * ztwogp * zvrel2 
    443                iter = 1 
    444                DO WHILE ( iter < 20 )  
    445                   zf  = ( ht_i_new(ji,jj) - zhicrit ) * ( ht_i_new(ji,jj) * ht_i_new(ji,jj) - zhicrit * zhicrit ) -   & 
    446                      &    ht_i_new(ji,jj) * zhicrit * ztwogp * zvrel2 
    447                   zfp = ( ht_i_new(ji,jj) - zhicrit ) * ( 3.0_wp * ht_i_new(ji,jj) + zhicrit ) - zhicrit * ztwogp * zvrel2 
    448  
    449                   ht_i_new(ji,jj) = ht_i_new(ji,jj) - zf / MAX( zfp, epsi20 ) 
    450                   iter = iter + 1 
    451                END DO 
    452                ! 
    453                ! bound ht_i_new (though I don't see why it should be necessary) 
    454                ht_i_new(ji,jj) = MAX( 0.01_wp, MIN( ht_i_new(ji,jj), hi_max(jpl) ) ) 
    455                ! 
    456             ELSE 
    457                ht_i_new(ji,jj) = 0._wp 
    458             ENDIF 
    459             ! 
    460          END_2D 
    461          !  
    462          CALL lbc_lnk( 'icethd', fraz_frac, 'T', 1.0_wp, ht_i_new, 'T', 1.0_wp  ) 
    463  
    464       ENDIF 
    465        
    466    END SUBROUTINE thd_prep 
    467252 
    468253   SUBROUTINE ice_thd_1d2d( kl, kn ) 
  • NEMO/trunk/src/ICE/icethd_do.F90

    r15334 r15388  
    1717   USE phycst         ! physical constants 
    1818   USE sbc_oce , ONLY : sss_m 
     19   USE sbc_ice , ONLY : utau_ice, vtau_ice 
    1920   USE ice1D          ! sea-ice: thermodynamics variables 
    2021   USE ice            ! sea-ice: variables 
     
    3435 
    3536   PUBLIC   ice_thd_do        ! called by ice_thd 
     37   PUBLIC   ice_thd_frazil    ! called by ice_thd 
    3638   PUBLIC   ice_thd_do_init   ! called by ice_stp 
    37  
    38    !                          !!** namelist (namthd_do) ** 
    39    REAL(wp), PUBLIC ::   rn_hinew      ! thickness for new ice formation (m) 
    40    LOGICAL , PUBLIC ::   ln_frazil     ! use of frazil ice collection as function of wind (T) or not (F) 
    41    REAL(wp), PUBLIC ::   rn_maxfraz    ! maximum portion of frazil ice collecting at the ice bottom 
    42    REAL(wp), PUBLIC ::   rn_vfraz      ! threshold drift speed for collection of bottom frazil ice 
    43    REAL(wp), PUBLIC ::   rn_Cfraz      ! squeezing coefficient for collection of bottom frazil ice 
    4439 
    4540   !! * Substitutions 
     
    337332 
    338333 
     334   SUBROUTINE ice_thd_frazil 
     335      !!----------------------------------------------------------------------- 
     336      !!                   ***  ROUTINE ice_thd_frazil *** 
     337      !! 
     338      !! ** Purpose :   frazil ice collection thickness and fraction 
     339      !! 
     340      !! ** Inputs  :   u_ice, v_ice, utau_ice, vtau_ice 
     341      !! ** Ouputs  :   ht_i_new, fraz_frac 
     342      !!----------------------------------------------------------------------- 
     343      INTEGER  ::   ji, jj             ! dummy loop indices 
     344      INTEGER  ::   iter 
     345      REAL(wp) ::   zvfrx, zvgx, ztaux, zf, ztenagm, zvfry, zvgy, ztauy, zvrel2, zfp, ztwogp 
     346      REAL(wp), PARAMETER ::   zcai    = 1.4e-3_wp                       ! ice-air drag (clem: should be dependent on coupling/forcing used) 
     347      REAL(wp), PARAMETER ::   zhicrit = 0.04_wp                         ! frazil ice thickness 
     348      REAL(wp), PARAMETER ::   zsqcd   = 1.0_wp / SQRT( 1.3_wp * zcai )  ! 1/SQRT(airdensity*drag) 
     349      REAL(wp), PARAMETER ::   zgamafr = 0.03_wp 
     350      !!----------------------------------------------------------------------- 
     351      ! 
     352      !---------------------------------------------------------! 
     353      ! Collection thickness of ice formed in leads and polynyas 
     354      !---------------------------------------------------------!     
     355      ! ht_i_new is the thickness of new ice formed in open water 
     356      ! ht_i_new can be either prescribed (ln_frazil=F) or computed (ln_frazil=T) 
     357      ! Frazil ice forms in open water, is transported by wind, accumulates at the edge of the consolidated ice edge 
     358      ! where it forms aggregates of a specific thickness called collection thickness. 
     359      ! 
     360      fraz_frac(:,:) = 0._wp 
     361      ! 
     362      ! Default new ice thickness 
     363      WHERE( qlead(:,:) < 0._wp ) ! cooling 
     364         ht_i_new(:,:) = rn_hinew 
     365      ELSEWHERE 
     366         ht_i_new(:,:) = 0._wp 
     367      END WHERE 
     368 
     369      IF( ln_frazil ) THEN 
     370         ztwogp  = 2._wp * rho0 / ( grav * 0.3_wp * ( rho0 - rhoi ) )  ! reduced grav 
     371         ! 
     372         DO_2D( 0, 0, 0, 0 ) 
     373            IF ( qlead(ji,jj) < 0._wp ) THEN ! cooling 
     374               ! -- Wind stress -- ! 
     375               ztaux = ( utau_ice(ji-1,jj  ) * umask(ji-1,jj  ,1) + utau_ice(ji,jj) * umask(ji,jj,1) ) * 0.5_wp 
     376               ztauy = ( vtau_ice(ji  ,jj-1) * vmask(ji  ,jj-1,1) + vtau_ice(ji,jj) * vmask(ji,jj,1) ) * 0.5_wp 
     377               ! Square root of wind stress 
     378               ztenagm = SQRT( SQRT( ztaux * ztaux + ztauy * ztauy ) ) 
     379 
     380               ! -- Frazil ice velocity -- ! 
     381               rswitch = MAX( 0._wp, SIGN( 1._wp , ztenagm - epsi10 ) ) 
     382               zvfrx   = rswitch * zgamafr * zsqcd * ztaux / MAX( ztenagm, epsi10 ) 
     383               zvfry   = rswitch * zgamafr * zsqcd * ztauy / MAX( ztenagm, epsi10 ) 
     384 
     385               ! -- Pack ice velocity -- ! 
     386               zvgx    = ( u_ice(ji-1,jj  ) * umask(ji-1,jj  ,1)  + u_ice(ji,jj) * umask(ji,jj,1) ) * 0.5_wp 
     387               zvgy    = ( v_ice(ji  ,jj-1) * vmask(ji  ,jj-1,1)  + v_ice(ji,jj) * vmask(ji,jj,1) ) * 0.5_wp 
     388 
     389               ! -- Relative frazil/pack ice velocity -- ! 
     390               rswitch = MAX( 0._wp, SIGN( 1._wp , at_i(ji,jj) - epsi10 ) ) 
     391               zvrel2  = MAX( (zvfrx - zvgx)*(zvfrx - zvgx) + (zvfry - zvgy)*(zvfry - zvgy), 0.15_wp*0.15_wp ) * rswitch 
     392 
     393               ! -- fraction of frazil ice -- ! 
     394               fraz_frac(ji,jj) = rswitch * ( TANH( rn_Cfraz * ( SQRT(zvrel2) - rn_vfraz ) ) + 1._wp ) * 0.5_wp * rn_maxfraz 
     395                
     396               ! -- new ice thickness (iterative loop) -- ! 
     397               ht_i_new(ji,jj) = zhicrit +   ( zhicrit + 0.1_wp )    & 
     398                  &                      / ( ( zhicrit + 0.1_wp ) * ( zhicrit + 0.1_wp ) -  zhicrit * zhicrit ) * ztwogp * zvrel2 
     399               iter = 1 
     400               DO WHILE ( iter < 20 )  
     401                  zf  = ( ht_i_new(ji,jj) - zhicrit ) * ( ht_i_new(ji,jj) * ht_i_new(ji,jj) - zhicrit * zhicrit ) -   & 
     402                     &    ht_i_new(ji,jj) * zhicrit * ztwogp * zvrel2 
     403                  zfp = ( ht_i_new(ji,jj) - zhicrit ) * ( 3.0_wp * ht_i_new(ji,jj) + zhicrit ) - zhicrit * ztwogp * zvrel2 
     404 
     405                  ht_i_new(ji,jj) = ht_i_new(ji,jj) - zf / MAX( zfp, epsi20 ) 
     406                  iter = iter + 1 
     407               END DO 
     408               ! 
     409               ! bound ht_i_new (though I don't see why it should be necessary) 
     410               ht_i_new(ji,jj) = MAX( 0.01_wp, MIN( ht_i_new(ji,jj), hi_max(jpl) ) ) 
     411               ! 
     412            ELSE 
     413               ht_i_new(ji,jj) = 0._wp 
     414            ENDIF 
     415            ! 
     416         END_2D 
     417         !  
     418         CALL lbc_lnk( 'icethd_frazil', fraz_frac, 'T', 1.0_wp, ht_i_new, 'T', 1.0_wp  ) 
     419 
     420      ENDIF 
     421   END SUBROUTINE ice_thd_frazil 
     422 
     423    
    339424   SUBROUTINE ice_thd_do_init 
    340425      !!----------------------------------------------------------------------- 
  • NEMO/trunk/src/ICE/icewri.F90

    r14997 r15388  
    2020   USE ice            ! sea-ice: variables 
    2121   USE icevar         ! sea-ice: operations 
     22   USE icealb , ONLY : rn_alb_oce 
    2223   ! 
    2324   USE ioipsl         ! 
     
    5354      REAL(wp) ::   z2da, z2db, zrho1, zrho2 
    5455      REAL(wp) ::   zmiss_val       ! missing value retrieved from xios 
    55       REAL(wp), DIMENSION(jpi,jpj)     ::   z2d, zfast                     ! 2D workspace 
     56      REAL(wp), DIMENSION(jpi,jpj)     ::   z2d                            ! 2D workspace 
    5657      REAL(wp), DIMENSION(jpi,jpj)     ::   zmsk00, zmsk05, zmsk15, zmsksn ! O%, 5% and 15% concentration mask and snow mask 
    5758      REAL(wp), DIMENSION(jpi,jpj,jpl) ::   zmsk00l, zmsksnl               ! cat masks 
     59      REAL(wp), DIMENSION(:,:), ALLOCATABLE ::   zfast, zalb, zmskalb      ! 2D workspace 
    5860      ! 
    5961      ! Global ice diagnostics (SIMIP) 
     
    131133      IF( iom_use('vice'    ) )   CALL iom_put( 'vice'   , v_ice    )                                                       ! ice velocity v 
    132134      ! 
    133       IF( iom_use('icevel') .OR. iom_use('fasticepres') ) THEN                                                              ! module of ice velocity 
     135      IF( iom_use('icevel') .OR. iom_use('fasticepres') ) THEN                                                              ! module of ice velocity & fast ice 
     136         ALLOCATE( zfast(jpi,jpj) ) 
    134137         DO_2D( 0, 0, 0, 0 ) 
    135138            z2da  = u_ice(ji,jj) + u_ice(ji-1,jj) 
     
    144147         END WHERE 
    145148         CALL iom_put( 'fasticepres', zfast ) 
    146       ENDIF 
    147  
     149         DEALLOCATE( zfast ) 
     150      ENDIF 
     151      ! 
     152      IF( iom_use('icealb') .OR. iom_use('albedo') ) THEN                                                                   ! ice albedo and surface albedo 
     153         ALLOCATE( zalb(jpi,jpj), zmskalb(jpi,jpj) ) 
     154         ! ice albedo 
     155         WHERE( at_i_b < 1.e-03 ) 
     156            zmskalb(:,:) = 0._wp 
     157            zalb   (:,:) = rn_alb_oce 
     158         ELSEWHERE 
     159            zmskalb(:,:) = 1._wp 
     160            zalb   (:,:) = SUM( alb_ice * a_i_b, dim=3 ) / at_i_b 
     161         END WHERE 
     162         CALL iom_put( 'icealb' , zalb * zmskalb + zmiss_val * ( 1._wp - zmskalb ) ) 
     163         ! ice+ocean albedo 
     164         zalb(:,:) = SUM( alb_ice * a_i_b, dim=3 ) + rn_alb_oce * ( 1._wp - at_i_b ) 
     165         CALL iom_put( 'albedo' , zalb ) 
     166         DEALLOCATE( zalb, zmskalb ) 
     167      ENDIF 
     168      ! 
    148169      ! --- category-dependent fields --- ! 
    149170      IF( iom_use('icemask_cat' ) )   CALL iom_put( 'icemask_cat' ,                  zmsk00l                                   ) ! ice mask 0% 
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