albedo_mk10.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.
!     ######spl
      FUNCTION albedo_mk10(PZENITH) RESULT(PDIR_ALB)
!     ##################################################################
!
!!****  *ALBEDO_MK10*  
!!
!!    PURPOSE
!!    -------
!       computes the direct albedo over open water
!
!     
!!**  METHOD
!!    ------
!
!!    EXTERNAL
!!    --------
!!
!!    IMPLICIT ARGUMENTS
!!    ------------------ 
!!
!!      
!!    REFERENCE
!!    ---------
!!    Modified version taken from SAM6.8 (Oct 2010) Marat Khairoutdinov 
!!    from CCM3). For the EUCLIPSE COMPOSITE CASE.
!!
!!      
!!    AUTHOR
!!    ------
!!      E. Bazile           * Meteo-France *
!!
!!    MODIFICATIONS
!!    -------------
!!      Original    28/03/11
!       
!-------------------------------------------------------------------------------
!
!*       0.     DECLARATIONS
!               ------------
!
USE yomhook   ,ONLY : lhook,   dr_hook
USE parkind1  ,ONLY : jprb
!
IMPLICIT NONE
!
!*      0.1    declarations of arguments
!              -------------------------
!
REAL, DIMENSION(:), INTENT(IN)  :: pzenith     ! zenithal angle (radian)
!
REAL, DIMENSION(SIZE(PZENITH))  :: pdir_alb    ! direct albedo on water
REAL, DIMENSION(SIZE(PZENITH))  :: zcoszrs     ! Cosine of solar zenith angle
REAL(KIND=JPRB) :: zhook_handle
!
!-------------------------------------------------------------------------------
!
IF (lhook) CALL dr_hook('ALBEDO_MK10',0,zhook_handle)
zcoszrs(:)  = max(cos(pzenith(:)),0.)
pdir_alb(:) = ( 0.026 / (zcoszrs**1.7 + .065)) + &
              (.15*(zcoszrs - 0.10) * (zcoszrs - 0.50) * (zcoszrs - 1.00) )
IF (lhook) CALL dr_hook('ALBEDO_MK10',1,zhook_handle)
!
!-------------------------------------------------------------------------------
!
END FUNCTION albedo_mk10