prep_ver_watflux.F90

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!SFX_LIC Copyright 1994-2014 CNRS, Meteo-France and Universite Paul Sabatier
!SFX_LIC This is part of the SURFEX software governed by the CeCILL-C licence
!SFX_LIC version 1. See LICENSE, CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt  
!SFX_LIC for details. version 1.
!     #########
SUBROUTINE prep_ver_watflux (W)
!     #################################################################################
!
!!****  *PREP_VER_WATFLUX* - change in WATFLUX var. due to altitude change
!!
!!    PURPOSE
!!    -------
!
!!**  METHOD
!!    ------
!!
!!    REFERENCE
!!    ---------
!!      
!!
!!    AUTHOR
!!    ------
!!     S. Malardel
!!
!!    MODIFICATIONS
!!    -------------
!!      Original    01/2004
!!------------------------------------------------------------------
!

!
!
USE modd_watflux_n, ONLY : watflux_t
!
USE modd_prep,       ONLY : xzs_ls, xt_clim_grad
USE modd_csts,       ONLY : xtt
!
!
USE yomhook   ,ONLY : lhook,   dr_hook
USE parkind1  ,ONLY : jprb
!
IMPLICIT NONE
!
!*      0.1    declarations of arguments
!
!
!*      0.2    declarations of local variables
!
!
TYPE(watflux_t), INTENT(INOUT) :: w
!
REAL, DIMENSION(:), ALLOCATABLE :: zts_ls ! large-scale water temperature
REAL(KIND=JPRB) :: zhook_handle
!
!-------------------------------------------------------------------------------------
!
!*      1.     Surface temperature of water
!
IF (lhook) CALL dr_hook('PREP_VER_WATFLUX',0,zhook_handle)
ALLOCATE(zts_ls(SIZE(w%XTS)))
zts_ls = w%XTS
!
w%XTS = zts_ls  + xt_clim_grad  * (w%XZS - xzs_ls)
!
!-------------------------------------------------------------------------------------
!
!*      2.     Limit on freezing
!
!* if water was already frozen, it can be considered liquid only for
!  temperatures that are larger than 4 C
!
WHERE (zts_ls < xtt .AND. w%XTS < xtt + 4.) w%XTS = min(w%XTS,xtt)
!
!* if water was liquid, it can be considered frozen only for
!  very cold temperatures, colder than 20 C. It should obviously 
!  depend on the size of the lake. This cold limit is taken for
!  large lakes, as US great lakes, that take a long time to freeze.
!
!  4 C is used here for the water of lowest density.
!
WHERE (zts_ls > xtt .AND. w%XTS > xtt - 20.) w%XTS = max(w%XTS,xtt+4.)
!
!-------------------------------------------------------------------------------------
!
!*      3.     Deallocation of large-scale orography
!
DEALLOCATE(zts_ls)
IF (lhook) CALL dr_hook('PREP_VER_WATFLUX',1,zhook_handle)
!
!-------------------------------------------------------------------------------------
!
END SUBROUTINE prep_ver_watflux