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!                     version 3; Last Modified: May 7, 2008.
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!

      real*8 FUNCTION LQTOES(lq,tt,pressure) 7,4
!
! Purpose:
!          to calculate the dew point depression from specific
!          humidity, temperature and pressure.  No ice phase
!          is permitted and the pressure vector is given.
!
      use MathPhysConstants_mod
      use physicsFunctions_mod
      implicit none
      real*8, intent(in) :: lq,tt,pressure
      real*8 :: husat,td
!
! get the saturated vapor pressure from lq (log of specific humidity)
!
      husat = foefq8(max(exp(lq),1.d-12),pressure)
!
! now the dewpoint temperature
!
      td = fotw8(husat)
!
! finally the dewpoint depression
!
      lqtoes = min(tt-td,MPC_MAXIMUM_ES_R8)

      return
      END FUNCTION LQTOES