PAULSON_PSIM_3D Function

FUNCTION PAULSON_PSIM_3D(PZ_O_LMO)
  USE MODD_CSTS
  IMPLICIT NONE  
  REAL, DIMENSION(:,:,:), INTENT(IN)                 :: PZ_O_LMO
  REAL, DIMENSION(SIZE(PZ_O_LMO,1), &
                    SIZE(PZ_O_LMO,2),SIZE(PZ_O_LMO,3)) :: PAULSON_PSIM_3D  
!
  REAL, DIMENSION(SIZE(PZ_O_LMO,1), &
                    SIZE(PZ_O_LMO,2),SIZE(PZ_O_LMO,3)) :: ZX  
  REAL(KIND=JPRB) :: ZHOOK_HANDLE

  IF (LHOOK) CALL DR_HOOK('MODE_SBLS:PAULSON_PSIM_3D',0,ZHOOK_HANDLE)
  ZX=1.
  WHERE ( PZ_O_LMO(:,:,:) < 0. )
    ZX=(1.-15.*PZ_O_LMO)**(0.25)
    PAULSON_PSIM_3D(:,:,:) = LOG( (1.+ZX**2)*(1+ZX)**2/8. ) - 2.*ATAN(ZX) + XPI/2.
  ELSEWHERE
    PAULSON_PSIM_3D(:,:,:) = - 4.7 * PZ_O_LMO
  END WHERE
IF (LHOOK) CALL DR_HOOK('MODE_SBLS:PAULSON_PSIM_3D',1,ZHOOK_HANDLE)
END FUNCTION PAULSON_PSIM_3D