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!Environment Canada - Atmospheric Science and Technology License/Disclaimer,
!                     version 3; Last Modified: May 7, 2008.
!This is free but copyrighted software; you can use/redistribute/modify it under the terms
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!
!
!  X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
!

      subroutine apc2UVg_c(psi,chi,pum,pvm) 1,4
!
!**s/r apc2UVg_c  - Adjoint of pc2UVg_gem.
!
!Author  : Luc Fillion - CGD/NCAR - 20 Feb 04
!Revision: Luc Fillion - MSC/CAN - 15 oct 2004 -GEM Arakawa-C grid.
!
!     -------------------
!*    Purpose: To build gridpoint analysis increments during 4D-Var.
!
!Arguments
!
      IMPLICIT NONE
#include "taglam4d.cdk"
#include "pardim.cdk"
#include "comgrd_param.cdk"
#include "comlun.cdk"
#include "comdim.cdk"
#include "comcst.cdk"
#include "comct0.cdk"
#include "comsim.cdk"
#include "comgemla.cdk"
!
      real*8 pum(0:ni+1,nflev,0:nj+1)
      real*8 pvm(0:ni+1,nflev,0:nj+1)
      real*8 psi(ni,nflev,nj)
      real*8 chi(ni,nflev,nj)
!
      integer ji,jj,jk,idim
      INTEGER myid,numthd,omp_get_thread_num,omp_get_num_threads
      real*8 zdlon,zdx,ztheta,ztheta1
      real*8 zcos2(0:nj+1),zcos2h(0:nj+1)
      real*8 zpsi(-1:ni+2,nflev,-1:nj+2)
      real*8 zchi(-1:ni+2,nflev,-1:nj+2)
!
!!
      idim=(ni+4)*(nj+4)*nflev
      call zero(idim,zpsi)
      call zero(idim,zchi)
!
      zdlon=rdlon_an(1,1)
      zdx=1./(ra*zdlon)
!
      do jj=0,nj+1
        zcos2(jj)=r1mmu2(jj)/(ra*rdmuh(jj-1))
        zcos2h(jj)=r1mmu2h(jj)/(ra*rdmu(jj))
      enddo
!
!$OMP PARALLEL PRIVATE(ji,jj,jk,myid,numthd)
      myid=omp_get_thread_num()+1
      numthd=omp_get_num_threads()
      do jk = myid,nflev,numthd
        do jj = nj, 0, -1
          do ji = ni+1, 1, -1
            zchi(ji,jk,jj+1) = zchi(ji,jk,jj+1)+pvm(ji,jk,jj)*zcos2h(jj)
            zchi(ji,jk,jj) = zchi(ji,jk,jj)-pvm(ji,jk,jj)*zcos2h(jj)
            zpsi(ji,jk,jj) = zpsi(ji,jk,jj)+pvm(ji,jk,jj)*zdx
            zpsi(ji-1,jk,jj) = zpsi(ji-1,jk,jj)-pvm(ji,jk,jj)*zdx
!cluc        pvm(ji,jk,jj) = 0.0
          enddo
        enddo
        do jj = nj+1, 1, -1
          do ji = ni, 0, -1
            zchi(ji+1,jk,jj) = zchi(ji+1,jk,jj)+pum(ji,jk,jj)*zdx
            zchi(ji,jk,jj) = zchi(ji,jk,jj)-pum(ji,jk,jj)*zdx
            zpsi(ji,jk,jj) = zpsi(ji,jk,jj)-pum(ji,jk,jj)*zcos2(jj)
            zpsi(ji,jk,jj-1) = zpsi(ji,jk,jj-1)+pum(ji,jk,jj)*zcos2(jj)
!cluc        pum(ji,jk,jj) = 0.0
          enddo
        enddo
      enddo
!$OMP END PARALLEL
!
! adjoint of: symmetrize
!
      call asymmetrize(psi,zpsi,ni,nj,nflev)
      call asymmetrize(chi,zchi,ni,nj,nflev)
!
      return
      end