#include <misc.h>#include <params.h>subroutine qmassa(cwava   ,w       ,q3      ,pdel    ,hw1lat  , &                  nlon    )!----------------------------------------------------------------------- ! ! Purpose: ! Calculate contribution of current latitude to mass of constituents! being advected by slt.! ! Method: ! ! Author: J. Olson! !-----------------------------------------------------------------------!! $Id: qmassa.F90,v 1.1 2001/11/06 18:42:50 erik Exp $! $Author: erik $!!-----------------------------------------------------------------------  use precision  use pmgrid  use tracers, only: pcnst, pnats  implicit none!------------------------------Arguments--------------------------------  integer , intent(in)  :: nlon                 ! longitude dimension    real(r8), intent(in)  :: cwava                ! normalization factor    l/(g*plon)  real(r8), intent(in)  :: w                    ! gaussian weight this latitude  real(r8), intent(in)  :: q3(plond,plev,pcnst) ! constituents  real(r8), intent(in)  :: pdel(plond,plev)     ! pressure diff between interfaces  real(r8), intent(out) :: hw1lat(pcnst)        ! accumulator!-----------------------------------------------------------------------!!---------------------------Local variables-----------------------------  integer i,k,m             ! longitude, level, constituent indices  real(r8) const            ! temporary constant!-----------------------------------------------------------------------!! Integration factor (the 0.5 factor arises because gaussian weights sum to 2)!  const = cwava*w*0.5  do m=1,pcnst     hw1lat(m) = 0.  end do!! Compute mass integral for water ONLY!  do k=1,plev     do i=1,nlon        hw1lat(1) = hw1lat(1) + q3(i,k,1)*pdel(i,k)     end do  end do!! Compute mass integral for non-water constituents (on a DRY basis)!  do m=2,pcnst     do k=1,plev        do i=1,nlon           hw1lat(m) = hw1lat(m) + q3(i,k,m)*(1. - q3(i,k,1))*pdel(i,k)        end do     end do  end do  do m = 1,pcnst     hw1lat(m) = hw1lat(m)*const  end do  returnend subroutine qmassa