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!Environment Canada - Atmospheric Science and Technology License/Disclaimer, 
!                     version 3; Last Modified: May 7, 2008.
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***fonction sgamasp - pente pseudo-adiabat sature (dt/dp)
*

      function sgamasp(tt, pr, swph, ti) 2,5
*
#include "impnone.cdk"
*
      real tt, pr, ti, sgamasp
*
      logical swph
*
*author
*       N. Brunet (septembre 2000)
*
*revision
*
*object
*       to calculate saturated pseudo-adiabatic lapse rate
*       dt/dp - deg K / pa
*       --------  dt/dp is > 0
*
*arguments
*       tt - temperature (K) at which we calculate the lapse rate
*       pr - pressure (pa) at which we calculate the lapse rate
*       swph - .true., to consider water and ice phase
*              .false, to consider water phase only
*       ti - temperature (K) at which we start calculating
*            latent heat of sublimation
*            if swph=false, ti is n/a
*            ti must be .LE. trpl
*
*note
*       we compute (- dt/dp): so the result is >0
*
*implicites
#include "consphy.cdk"
*modules
      external inctphy, schal
*
**
*---------------------------------------------------------------
*
      real schal
      real latheat, lvt0, lsti, x, z
*
#include "dintern.cdk"
#include "fintern.cdk"
*
*--------------------------------------------------------------------
#include "initcph.cdk"
*
*     calcule la chaleur latente
      latheat = schal(tt, ti, swph)
*
      x = latheat / rgasd
      z = eps1 * latheat**2 / (rgasd * cpd)
*
      if(swph)then
         sgamasp = dble(cappa)*tt/pr*(1.d0+dble(x)*foqst(tt,pr)/tt) /
     +             (1.d0+dble(z)*foqst(tt,pr)/tt**2)
      else
         sgamasp = dble(cappa)*tt/pr*(1.d0+dble(x)*foqsa(tt,pr)/tt) /
     +             (1.d0+dble(z)*foqsa(tt,pr)/tt**2)
      end if
*
      return
      CONTAINS
#include "fintern90.cdk"
      end