wind_threshold.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.
!     #########
    FUNCTION wind_threshold(PWIND,PUREF) RESULT(PWIND_NEW)
!   ############################################################################
!
!!****  *WIND_THRESHOLD*  
!!
!!    PURPOSE
!!    -------
!
!     Set a minimum value to the wind for exchange coefficient computations.
!     This minimum value depends on the forcing height
!     
!!    AUTHOR
!!    ------
!!
!!      V. Masson           * Meteo-France *
!!
!!    MODIFICATIONS
!!    -------------
!!      Original    09/2007 
!-------------------------------------------------------------------------------
!
USE modd_surf_atm, ONLY: xcismin, xvmodmin, laldthres
!
!*       0.     DECLARATIONS
!               ------------
!
!
USE yomhook   ,ONLY : lhook,   dr_hook
USE parkind1  ,ONLY : jprb
!
IMPLICIT NONE
!
!*      0.1    declarations of arguments
!
!
REAL, DIMENSION(:), INTENT(IN)   :: PWIND      ! wind
REAL, DIMENSION(:), INTENT(IN)   :: PUREF      ! forcing level
!
REAL, DIMENSION(SIZE(PWIND))     :: PWIND_NEW  ! modified wind
REAL(KIND=JPRB) :: ZHOOK_HANDLE
!
!
!
!*      0.2    declarations of local variables
!
!-------------------------------------------------------------------------------
!
!  wind gradient
!
IF (lhook) CALL dr_hook('WIND_THRESHOLD',0,zhook_handle)
IF (.NOT.laldthres) THEN
!        
!  minimum value for exchange coefficients computations : 1m/s / 10m
   pwind_new = max(pwind , 0.1 * min(10.,puref) )
ELSE
!  minimum value for exchange coefficients computations : 1m/s / 10m
   pwind_new = max( xvmodmin, sqrt( pwind**2 + (xcismin*puref)**2 ) )
ENDIF
IF (lhook) CALL dr_hook('WIND_THRESHOLD',1,zhook_handle)
!
!-------------------------------------------------------------------------------
!
END FUNCTION wind_threshold