LIM-3: small bug in latent heat of solid precipitation melting

[gm]

In LIM-3 a betas exponent has been introduced when computing the solid precipitation over the sea ice. Part of the snow that falls over sea-ice is put in the lead areas by the wind. Nevertheless, the latent heat flux due to snow melting is computed with sprecip *(1-at_i) whereas the actual solid precipitation over lead area is sprecip*(1-at_ibetas) (see limsbc.F90). If betas /=1, some latent heat is missing.

In limthd.F90 the following lines:

            zfontn         = sprecip(ji,jj) * lfus              ! energy of melting
            zfnsol         = qns(ji,jj)                         ! total non solar flux
            qldif(ji,jj)   = tms(ji,jj) * ( qsr(ji,jj)                               &
               &                               + zfnsol + fdtcn(ji,jj) - zfontn      &
               &                               + ( 1.0 - zindb ) * fsbbq(ji,jj)  )   &
               &                               * ( 1.0 - at_i(ji,jj) ) * rdt_ice    

should be replace by

            qldif(ji,jj) =  tms(ji,jj) * rdt_ice  &
               &   * (   ( 1.0 - at_i(ji,jj) ) * (   qsr(ji,jj)                          &   ! solar heat
               &                                   + qns(ji,jj)                          &   ! non solar heat
               &                                   + fdtcn(ji,jj)                        &   ! turbulent ice-ocean heat
               &                                   + ( 1.0 - zindb ) * fsbbq(ji,jj)  )   &   ! residual heat from previous step
               &       - sprecip(ji,jj) * lfus * pfrld(ji,jj)**betas                   ) &   ! latent heat of sprecip melting

and remove the declaration of zfontn and zfnsol, not used anymore

Gurvan

[gm]

done in v3.3 beta (see changeset 2383)

TO BE DONE in v3.2

[smasson]

done in trunk of v3.2.1, see changeset #2387