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!

      real*8 FUNCTION LQTOES_TL(delLQ,delTT,delP0,LQ_g,PRES_g,dPdPsfc) 3,8
!
! Purpose: TLM VERSION
!          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) :: delLQ,delTT,delP0,LQ_g,PRES_g,dPdPsfc
      REAL(8) :: ZE,ZTD,dTDdE,ZQBRANCH,HU_g
      REAL(8) :: dESdLQ,dESdTT,dESdP0

      dESdTT = 1.0d0
*
* Forward calculations of saturation vapour pressure and dewpoint temperature
* and adjoint of vapour pressure from adjoint of dewpoint temperature
*
      HU_g = exp(LQ_g)
      ZE = FOEFQ8(HU_g, PRES_g)

      ZTD=FOTW8(ZE)
      dTDdE=FODTW8(ZTD,ZE)
*
* adjoint of temp. specific humidity and surface pressure due to changes in vapour pressure
*
      ZQBRANCH = FQBRANCH(HU_g)
      dESdLQ = - ZQBRANCH*FOEFQA(1.0d0,dTDdE,HU_g,PRES_g)

      dESdP0 = - ZQBRANCH*FOEFQPSA(1.0d0,dTDdE,HU_g,dPdPsfc)-
     &           (1.D0-ZQBRANCH)*(dTDdE*dPdPsfc)

      lqtoes_tl =  dESdLQ*delLQ + dESdP0*delP0 + dESdTT*delTT

      return
      END FUNCTION LQTOES_TL