Changeset 4924 for branches/2014/dev_r4650_UKMO2_ice_shelves/NEMOGCM/NEMO/OPA_SRC/SBC/sbcblk_core.F90

Timestamp:

2014-11-28T18:24:01+01:00 (9 years ago)

Author:

mathiot

Message:

UKM02_ice_shelves merged and SETTE tested with revision 4879 of trunk

File:

• branches/2014/dev_r4650_UKMO2_ice_shelves/NEMOGCM/NEMO/OPA_SRC/SBC/sbcblk_core.F90 (modified) (5 diffs)

branches/2014/dev_r4650_UKMO2_ice_shelves/NEMOGCM/NEMO/OPA_SRC/SBC/sbcblk_core.F90

@@ -566 +566 @@
       zcoef_dqsb   = rhoa * cpa * Cice
       zcoef_frca   = 1.0  - 0.3
+      ! MV 2014 the proper cloud fraction (mean summer months from the CLIO climato, NH+SH) is 0.19
+      zcoef_frca   = 1.0  - 0.19
 
 !!gm brutal....
@@ -651 +653 @@
                p_qsr(ji,jj,jl) = zztmp * ( 1. - palb(ji,jj,jl) ) * qsr(ji,jj)
                ! Long  Wave (lw)
-               ! iovino
-               IF( ff(ji,jj) .GT. 0._wp ) THEN
-                  z_qlw(ji,jj,jl) = ( 0.95 * sf(jp_qlw)%fnow(ji,jj,1) - Stef * pst(ji,jj,jl) * zst3 ) * tmask(ji,jj,1)
-               ELSE
-                  z_qlw(ji,jj,jl) = 0.95 * ( sf(jp_qlw)%fnow(ji,jj,1) - Stef * pst(ji,jj,jl) * zst3 ) * tmask(ji,jj,1)
-               ENDIF
+               z_qlw(ji,jj,jl) = 0.95 * ( sf(jp_qlw)%fnow(ji,jj,1) - Stef * pst(ji,jj,jl) * zst3 ) * tmask(ji,jj,1)
                ! lw sensitivity
                z_dqlw(ji,jj,jl) = zcoef_dqlw * zst3                                               
@@ -671 +668 @@
                   &                         * (  11637800. * EXP( -5897.8 / pst(ji,jj,jl) ) / rhoa - sf(jp_humi)%fnow(ji,jj,1)  ) )
                ! Latent heat sensitivity for ice (Dqla/Dt)
-               p_dqla(ji,jj,jl) = rn_efac * zcoef_dqla * z_wnds_t(ji,jj) / ( zst2 ) * EXP( -5897.8 / pst(ji,jj,jl) )
+               ! MV we also have to cap the sensitivity if the flux is zero
+               IF ( p_qla(ji,jj,jl) .GT. 0.0 ) THEN
+                  p_dqla(ji,jj,jl) = rn_efac * zcoef_dqla * z_wnds_t(ji,jj) / ( zst2 ) * EXP( -5897.8 / pst(ji,jj,jl) )
+               ELSE
+                  p_dqla(ji,jj,jl) = 0.0
+               ENDIF
+                             
                ! Sensible heat sensitivity (Dqsb_ice/Dtn_ice)
                z_dqsb(ji,jj,jl) = zcoef_dqsb * z_wnds_t(ji,jj)
@@ -823 +826 @@
            sqrt_Cd=kappa/((kappa/sqrt_Cd_n10) - zpsi_m) ; Cd=sqrt_Cd*sqrt_Cd;
          ELSE
-           !! Shifting the wind speed to 10m and neutral stability :
-           U_n10 = dU10*1./(1. + sqrt_Cd_n10/kappa*(log(zu/10.) - zpsi_m)) !  L & Y eq. (9a)
+           !! Shifting the wind speed to 10m and neutral stability :  L & Y eq. (9a)
+           !   In very rare low-wind conditions, the old way of estimating the
+           !   neutral wind speed at 10m leads to a negative value that causes the code
+           !   to crash. To prevent this a threshold of 0.25m/s is now imposed.
+           U_n10 = MAX( 0.25 , dU10/(1. + sqrt_Cd_n10/kappa*(log(zu/10.) - zpsi_m)) )
 
            !! Updating the neutral 10m transfer coefficients :
@@ -959 +965 @@
          zpsi_m  = psi_m(zeta_u)
          !!
-         !! Shifting the wind speed to 10m and neutral stability : (L & Y eq.(9a))
-!        U_n10 = dU10/(1. + sqrt_Cd_n10/kappa*(log(zu/10.) - psi_m(zeta_u)))
-         U_n10 = dU10/(1. + sqrt_Cd_n10/kappa*(log(zu/10.) - zpsi_m))
+         !! Shifting the wind speed to 10m and neutral stability : L & Y eq.(9a)
+         !   In very rare low-wind conditions, the old way of estimating the
+         !   neutral wind speed at 10m leads to a negative value that causes the code
+         !   to crash. To prevent this a threshold of 0.25m/s is now imposed.
+         U_n10 = MAX( 0.25 , dU10/(1. + sqrt_Cd_n10/kappa*(log(zu/10.) - zpsi_m)) )
          !!
          !! Shifting temperature and humidity at zu :          (L & Y eq. (9b-9c))