#include <misc.h>#include <params.h>subroutine etadtn(lat   ,nlon    ,d       ,edstar  ,etadot  )!!-----------------------------------------------------------------------!! Purpose:! to compute (1/ps)etadot(dp/deta) for time steps subsequent to nstep = 0.! This routine completes a partial computation which began in the previous! time step (SCANDYN)!! NOTE:  Computing only the bottom "pver" levels of a half-level field.!! Author:  J. Olson!!-----------------------------------------------------------------------!! $Id: etadtn.F90,v 1.4 2001/09/16 19:46:43 pworley Exp $! $Author: pworley $!!-----------------------------------------------------------------------  use precision  use pmgrid  implicit none#include <comhyb.h>!------------------------------Arguments--------------------------------!  integer, intent(in) :: lat                     ! latitude  integer, intent(in) :: nlon                    ! number of longitudes  real(r8), intent(in)   :: d     (plond,plev)   ! divergence  real(r8), intent(in)   :: edstar(plond,plev)   ! partially computed etadot  real(r8), intent(out)  :: etadot(plond,plev)   ! vertical velocity in eta coordinates!!-----------------------------------------------------------------------!! local workspace!  integer i,k               ! indices  real(r8) ddpn(plond)      ! divergence integral  real(r8) ddpk(plond)      ! divergence accumulator  real(r8) dpr (plev)       ! pressure coefficient!!-----------------------------------------------------------------------!  do i = 1,nlon     ddpn(i) = 0.     ddpk(i) = 0.  end do!  do k = 1,plev     dpr(k) = hypd(k)/hypi(plevp)  end do!  do k = 1,plev     do i = 1,nlon        ddpn(i) = ddpn(i) + d(i,k)*dpr(k)     end do  end do!  do k = 1,plev-1     do i = 1,nlon        ddpk(i) = ddpk(i) + d(i,k)*dpr(k)        etadot(i,k) = edstar(i,k) - ddpk(i)     end do     if(k.ge.nprlev) then        do i = 1,nlon           etadot(i,k) = etadot(i,k) + hybi(k+1)*ddpn(i)        end do     endif  end do!! Finish bottom level!  do i = 1,nlon     etadot(i,plev) = 0.  end do!  returnend subroutine etadtn