! $Id: CMN_GCTM,v 1.1 2009/06/09 21:51:50 daven Exp $

      !=================================================================
      ! CMN_GCTM contains GEOS-CHEM specific PHYSICAL CONSTANTS
      ! and DERIVED QUANTITIES (bmy, 6/25/02, 6/23/03)
      !
      ! NOTES:
      ! (1 ) Changed RCS ID tag comment character from "C" to "!$" to
      !       allow freeform compilation.  Also convert PARAMETERS to F90
      !       syntax. Updated comments, cosmetic changes. (bmy, 6/25/02)
      ! (2 ) Added atmospheric scale height (7.6 km) (bmy, 6/23/03)
      !=================================================================

      ! AIRMW : Molecular weight of air [28.97 g/mole]
      REAL*8, PARAMETER :: AIRMW  =  28.97d0

      ! g0    : Gravity at Surface of Earth [9.8 m/s^2]
      REAL*8, PARAMETER :: g0     =   9.8d0

      ! PI    : Double-Precision value of PI
      REAL*8, PARAMETER :: PI     =   3.14159265358979323d0

      ! Re    : Radius of Earth [m]
      REAL*8, PARAMETER :: Re     =   6.375d6

      ! Rd    : Gas Constant (R) in Dry Air [287 J/K/kg]
      REAL*8, PARAMETER :: Rd     = 287.0d0

      ! g0_100 = 100.0 / g0
      REAL*8, PARAMETER :: g0_100 = 100d0 / g0

      ! PI_180 = PI    / 180.0
      REAL*8, PARAMETER :: PI_180 =    PI / 180d0

      ! Rdg0   = Rd    / g0
      REAL*8, PARAMETER :: Rdg0   =    Rd / g0

      ! Scale height of atmosphere (7.6 km = 7600m)
      REAL*8, PARAMETER :: SCALE_HEIGHT = 7600d0