! +-======-+ 
!  Copyright (c) 2003-2018 United States Government as represented by 
!  the Admistrator of the National Aeronautics and Space Administration.  
!  All Rights Reserved.
!  
!  THIS OPEN  SOURCE  AGREEMENT  ("AGREEMENT") DEFINES  THE  RIGHTS  OF USE,
!  REPRODUCTION,  DISTRIBUTION,  MODIFICATION AND REDISTRIBUTION OF CERTAIN 
!  COMPUTER SOFTWARE ORIGINALLY RELEASED BY THE UNITED STATES GOVERNMENT AS 
!  REPRESENTED BY THE GOVERNMENT AGENCY LISTED BELOW ("GOVERNMENT AGENCY").  
!  THE UNITED STATES GOVERNMENT, AS REPRESENTED BY GOVERNMENT AGENCY, IS AN 
!  INTENDED  THIRD-PARTY  BENEFICIARY  OF  ALL  SUBSEQUENT DISTRIBUTIONS OR 
!  REDISTRIBUTIONS  OF THE  SUBJECT  SOFTWARE.  ANYONE WHO USES, REPRODUCES, 
!  DISTRIBUTES, MODIFIES  OR REDISTRIBUTES THE SUBJECT SOFTWARE, AS DEFINED 
!  HEREIN, OR ANY PART THEREOF,  IS,  BY THAT ACTION, ACCEPTING IN FULL THE 
!  RESPONSIBILITIES AND OBLIGATIONS CONTAINED IN THIS AGREEMENT.
!  
!  Government Agency: National Aeronautics and Space Administration
!  Government Agency Original Software Designation: GSC-15354-1
!  Government Agency Original Software Title:  GEOS-5 GCM Modeling Software
!  User Registration Requested.  Please Visit http://opensource.gsfc.nasa.gov
!  Government Agency Point of Contact for Original Software:  
!  			Dale Hithon, SRA Assistant, (301) 286-2691
!  
! +-======-+ 
!
! from Larry- to fill up NP data void
      SUBROUTINE fill_NPOLE (q,im,jm,undef)
!---------------------------------------------------------------------------
      IMPLICIT NONE

       INTEGER,                      INTENT(IN)       :: im,jm
       REAL,                         INTENT(IN)       :: undef
       REAL,                         INTENT(INOUT)    :: q(im,jm)

       INTEGER               i,j,j1,j2,iph,num
       REAL                  qi(im,jm)
       REAL                  qo(im,jm)
!---------------------------------------------------------------------------
       qi = q
       qo = q

       do i=1,im
           j1=jm
           do while( qi(i,j1).eq.undef )
              j1=j1-1
           end do
           num = jm-j1

!          go across the NP
           iph = i + im/2
           if( iph.gt.im ) iph = iph-im
           j2=jm
           do while( qi(iph,j2).eq.undef )
              j2=j2-1
           end do

!          linearly interp
           num = num+jm-j2
           do j=j1+1,jm
              qo(i,j) = qi(i,j1) + (qi(iph,j2)-qi(i,j1))*(j-j1)/num
           enddo
       enddo

       q = qo

      RETURN
!---------------------------------------------------------------------------
      END SUBROUTINE fill_NPOLE
!