!$Author: joelevin $
!$Date: 2011-03-24 11:33:26 -0500 (Thu, 24 Mar 2011) $
!$Revision: 11724 $
!$HeadURL: https://svn.weru.ksu.edu/weru/weps1/trunk/weps.src/src/lib_hydro/preslaps.for $

      real function preslaps( elevation )

      ! returns the standard atmospheric pressure (kpa) as a function of
      ! elevation (m) based on curve fit by Abdu Durar to standard U.S.
      ! Atmosphere tables

      real elevation
      ! elevation  - elevation of location (m)

      real a1, a2, a3
      ! a1,a2,a3 - constants used to compute barametric pressure
      parameter   (a1 = 824.4996, a2 = 35702.8022, a3 = -607945000.)

      preslaps = a1 * exp(((elevation + a2)**2.) / a3)              !h-15

      return
      end