!-------------------------------------- LICENCE BEGIN ------------------------------------
!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
!of the Environment Canada - Atmospheric Science and Technology License/Disclaimer
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!
!This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
!without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
!See the above mentioned License/Disclaimer for more details.
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!CANADA, H9P 1J3; or send e-mail to service.rpn@ec.gc.ca
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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 UV2zdg_c(pzm,pdm,pu,pv) 1,8
!
!**s/r UV2zdg_c  - Compute gridpoint (Vort,Div) from gridpoint Wind-Images (U,V).
!
!Author  : Luc Fillion - MSC/CAN - 10 Sept 04.
!Revision:
!
!     -------------------
!*    Purpose: Necessary for background error statistic computations.
!
!Arguments
!
      IMPLICIT NONE
#include "taglam4d.cdk"
#include "pardim.cdk"
#include "comgrd_param.cdk"
#include "comdim.cdk"
#include "comlun.cdk"
#include "comcst.cdk"
#include "comct0.cdk"
#include "comsim.cdk"
#include "comgemla.cdk"
!
      real*8 pzm(ni,nflev,nj)
      real*8 pdm(ni,nflev,nj)
      real*8 pu(0:ni+1,nflev,0:nj+1)
      real*8 pv(0:ni+1,nflev,0:nj+1)
!
      integer ji,jj,jk,idim
      real*8 zdlon,zdx,ztheta,ztheta1
      real*8 zcos2(0:nj+1),zcos2h(0:nj+1)
      real*8 zidmu(nj),zidmuh(0:nj-1),zira
!
!!
      call zero(ni*nj*nflev,pzm)
      call zero(ni*nj*nflev,pdm)
!
      zdlon=rdlon_an(1,1)
      if(rdlon_an(1,1).le.0.) then
        call abort3d(nulout,'UV2zdg_c: rdlon_an(1,1).le.0.')
      endif
      if(ra.le.0.) then
        call abort3d(nulout,'UV2zdg_c: ra.le.0.')
      endif
      zdx=1./(ra*zdlon)
      zira=1./ra
!
      do jj=0,nj-1
        if(rdmuh(jj).le.0.) then
          write(nulout,*) 'UV2zdg_c: jj = ',jj
          call abort3d(nulout,'UV2zdg_c: rdmuh(jj).le.0.')
        endif
        zidmuh(jj)= 1./rdmuh(jj)
      enddo
!
      do jj=1,nj
        if(rdmu(jj).le.0.) then
          write(nulout,*) 'UV2zdg_c: jj = ',jj
          call abort3d(nulout,'UV2zdg_c: rdmu(jj).le.0.')
        endif
        if(r1mmu2(jj).le.0.) then
          write(nulout,*) 'UV2zdg_c: jj = ',jj
          call abort3d(nulout,'UV2zdg_c: r1mmu2(jj).le.0.')
        endif
        if(rdmuh(jj).le.0.) then
          write(nulout,*) 'UV2zdg_c: jj = ',jj
          call abort3d(nulout,'UV2zdg_c: r1mmu2h(jj).le.0.')
        endif
        zidmu(jj)= 1./rdmu(jj)
        zcos2(jj)=1.0/r1mmu2(jj)
        zcos2h(jj)=1.0/r1mmu2h(jj)
      enddo
!
      do jk=1,nflev
      do jj=1,nj
      do ji=1,ni
        pzm(ji,jk,jj)=zcos2h(jj)*zdx*(pv(ji+1,jk,jj)-pv(ji,jk,jj))
     &        -zira*zidmu(jj)*(pu(ji,jk,jj+1)-pu(ji,jk,jj))
      enddo
      enddo
      enddo
!
      do jk=1,nflev
      do jj=1,nj
      do ji=1,ni
        pdm(ji,jk,jj)=zcos2(jj)*zdx*(pu(ji,jk,jj)-pu(ji-1,jk,jj))
     &        +zira*zidmuh(jj-1)*(pv(ji,jk,jj)-pv(ji,jk,jj-1))
      enddo
      enddo
      enddo
!
      return
      end