subroutine MPP_WRITE_2DDECOMP_2D_( unit, field, domain, data, tstamp, tile_count, default_data)
      integer, intent(in) :: unit
      type(fieldtype), intent(in) :: field
      type(domain2D), intent(inout) :: domain
      MPP_TYPE_, intent(inout) :: data(:,:)
      real,              intent(in), optional :: tstamp
      integer,           intent(in), optional :: tile_count
      MPP_TYPE_,         intent(in), optional :: default_data

      MPP_TYPE_ :: data3D(size(data,1),size(data,2),1)
      pointer( ptr, data3D )
      ptr = LOC(data)

      call mpp_write( unit, field, domain, data3D, tstamp, tile_count, default_data)
      return
    end subroutine MPP_WRITE_2DDECOMP_2D_

    subroutine MPP_WRITE_2DDECOMP_3D_( unit, field, domain, data, tstamp, tile_count, default_data)
!mpp_write writes <data> which has the domain decomposition <domain>
      integer,           intent(in)           :: unit
      type(fieldtype),   intent(in)           :: field
      type(domain2D),    intent(inout)        :: domain 
      MPP_TYPE_,         intent(inout)        :: data(:,:,:)
      real,              intent(in), optional :: tstamp
      integer,           intent(in), optional :: tile_count
      MPP_TYPE_,         intent(in), optional :: default_data

!cdata is used to store compute domain as contiguous data
!gdata is used to globalize data for multi-PE single-threaded I/O
      MPP_TYPE_, allocatable, dimension(:,:,:) :: cdata, gdata
!NEW: data may be on compute OR data domain
      logical :: data_has_halos, halos_are_global, x_is_global, y_is_global
      integer :: is, ie, js, je, isd, ied, jsd, jed, isg, ieg, jsg, jeg, ism, iem, jsm, jem
      integer :: position, errunit
      type(domain2d), pointer :: io_domain=>NULL()

      call mpp_clock_begin(mpp_write_clock)

      errunit = stderr()
      if( .NOT.module_is_initialized )call mpp_error( FATAL, 'MPP_WRITE: must first call mpp_io_init.' )
      if( .NOT.mpp_file(unit)%valid )call mpp_error( FATAL, 'MPP_WRITE: invalid unit number.' )

      position = field%position

      call mpp_get_compute_domain( domain, is,  ie,  js,  je, tile_count=tile_count, position=position  )
      call mpp_get_data_domain   ( domain, isd, ied, jsd, jed, x_is_global=x_is_global, &
                                   y_is_global=y_is_global, tile_count=tile_count, position=position )
      call mpp_get_memory_domain ( domain, ism, iem, jsm, jem, position=position )

      if( size(data,1).EQ.ie-is+1 .AND. size(data,2).EQ.je-js+1 )then
          data_has_halos = .FALSE.
      else if( size(data,1).EQ.iem-ism+1 .AND. size(data,2).EQ.jem-jsm+1 )then
          data_has_halos = .TRUE.
      else
          write( errunit,'(a,10i5)' )'MPP_WRITE_2DDECOMP fails on field '//trim(field%name)// &
               ': is,ie,js,je, ism,iem,jsm,jem, size(data,1), size(data,2)=', &
               is,ie,js,je, ism,iem,jsm,jem, size(data,1), size(data,2)
          call mpp_error( FATAL, 'MPP_WRITE: data must be either on compute domain or data domain.' )
      end if
      halos_are_global = x_is_global .AND. y_is_global
      if( npes.GT.1 .AND. mpp_file(unit)%threading.EQ.MPP_SINGLE )then
          if( halos_are_global )then
              call mpp_update_domains( data, domain, position = position )
!all non-0 PEs have passed their data to PE 0 and may now exit
              if(mpp_file(unit)%write_on_this_pe ) then
                 call write_record( unit, field, size(data(:,:,:)), data, tstamp)
              endif
          else
!put field onto global domain
              call mpp_get_global_domain ( domain, isg, ieg, jsg, jeg, tile_count=tile_count, position=position )
              if(mpp_file(unit)%write_on_this_pe .OR. .NOT. global_field_on_root_pe) then
                  allocate( gdata(isg:ieg,jsg:jeg,size(data,3)) )
              else
                  allocate( gdata(1,1,1))
              endif
              if(global_field_on_root_pe) then
                 call mpp_global_field( domain, data, gdata, position = position, &
                                        flags=XUPDATE+YUPDATE+GLOBAL_ROOT_ONLY,   &
                                        default_data=default_data)
              else
                 call mpp_global_field( domain, data, gdata, position = position, &
                                        default_data=default_data)
              endif
!all non-0 PEs have passed their data to PE 0 and may now exit
              if(mpp_file(unit)%write_on_this_pe ) then
                 call write_record( unit, field, size(gdata(:,:,:)), gdata, tstamp)
              endif
              deallocate(gdata)
          end if
      else if(mpp_file(unit)%io_domain_exist ) then
          if( halos_are_global )then
              call mpp_update_domains( data, domain, position = position )
              if(mpp_file(unit)%write_on_this_pe ) then
                 call write_record( unit, field, size(data(:,:,:)), data, tstamp)
              endif
          else
              io_domain=>mpp_get_io_domain(mpp_file(unit)%domain) 
              call mpp_get_global_domain ( io_domain, isg, ieg, jsg, jeg, tile_count=tile_count, position=position )
              if(mpp_file(unit)%write_on_this_pe .OR. .NOT. global_field_on_root_pe) then
                 allocate( gdata(isg:ieg,jsg:jeg,size(data,3)) )
              else
                 allocate( gdata(1,1,1))
              endif
              if(global_field_on_root_pe) then
                 call mpp_global_field( io_domain, data, gdata, position = position, &
                                        flags=XUPDATE+YUPDATE+GLOBAL_ROOT_ONLY,      &
                                        default_data=default_data)
              else
                 call mpp_global_field( io_domain, data, gdata, position = position, &
                                        default_data=default_data)
              endif
              io_domain => NULL()
              if(mpp_file(unit)%write_on_this_pe ) then
                 call write_record( unit, field, size(gdata(:,:,:)), gdata, tstamp)
              endif
              deallocate( gdata )
          endif
      else if( data_has_halos )then
!store compute domain as contiguous data and pass to write_record
          allocate( cdata(is:ie,js:je,size(data,3)) )
          cdata(:,:,:) = data(is-isd+1:ie-isd+1,js-jsd+1:je-jsd+1,:)
          call write_record( unit, field, size(cdata(:,:,:)), cdata, tstamp, domain, tile_count=tile_count ) 
      else
!data is already contiguous
          call write_record( unit, field, size(data(:,:,:)), data, tstamp, domain, tile_count=tile_count )
      end if

      call mpp_clock_end(mpp_write_clock)

      return
    end subroutine MPP_WRITE_2DDECOMP_3D_

    subroutine MPP_WRITE_2DDECOMP_4D_( unit, field, domain, data, tstamp, tile_count, default_data)
!mpp_write writes <data> which has the domain decomposition <domain>
      integer,           intent(in)           :: unit
      type(fieldtype),   intent(in)           :: field
      type(domain2D),    intent(inout)        :: domain 
      MPP_TYPE_,         intent(inout)        :: data(:,:,:,:)
      real,              intent(in), optional :: tstamp
      integer,           intent(in), optional :: tile_count
      MPP_TYPE_,         intent(in), optional :: default_data

!cdata is used to store compute domain as contiguous data
!gdata is used to globalize data for multi-PE single-threaded I/O
      MPP_TYPE_, allocatable, dimension(:,:,:,:) :: cdata, gdata
!NEW: data may be on compute OR data domain
      logical :: data_has_halos, halos_are_global, x_is_global, y_is_global
      integer :: is, ie, js, je, isd, ied, jsd, jed, isg, ieg, jsg, jeg, ism, iem, jsm, jem
      integer :: position, errunit
      type(domain2d), pointer :: io_domain=>NULL()

      errunit = stderr()
      call mpp_clock_begin(mpp_write_clock)

      if( .NOT.module_is_initialized )call mpp_error( FATAL, 'MPP_WRITE: must first call mpp_io_init.' )
      if( .NOT.mpp_file(unit)%valid )call mpp_error( FATAL, 'MPP_WRITE: invalid unit number.' )

      position = field%position

      call mpp_get_compute_domain( domain, is,  ie,  js,  je, tile_count=tile_count, position=position  )
      call mpp_get_data_domain   ( domain, isd, ied, jsd, jed, x_is_global=x_is_global, &
                                   y_is_global=y_is_global, tile_count=tile_count, position=position )
      call mpp_get_memory_domain ( domain, ism, iem, jsm, jem, position=position )

      if( size(data,1).EQ.ie-is+1 .AND. size(data,2).EQ.je-js+1 )then
          data_has_halos = .FALSE.
      else if( size(data,1).EQ.iem-ism+1 .AND. size(data,2).EQ.jem-jsm+1 )then
          data_has_halos = .TRUE.
      else
          write( errunit,'(a,10i5)' )'MPP_WRITE_2DDECOMP fails on field '//trim(field%name)// &
               ': is,ie,js,je, ism,iem,jsm,jem, size(data,1), size(data,2)=', &
               is,ie,js,je, ism,iem,jsm,jem, size(data,1), size(data,2)
          call mpp_error( FATAL, 'MPP_WRITE: data must be either on compute domain or data domain.' )
      end if
      halos_are_global = x_is_global .AND. y_is_global
      if( npes.GT.1 .AND. mpp_file(unit)%threading.EQ.MPP_SINGLE )then
          if( halos_are_global )then
              call mpp_update_domains( data, domain, position = position )
!all non-0 PEs have passed their data to PE 0 and may now exit
              if(mpp_file(unit)%write_on_this_pe ) then
                 call write_record( unit, field, size(data(:,:,:,:)), data, tstamp)
              endif
          else
!put field onto global domain
              call mpp_get_global_domain ( domain, isg, ieg, jsg, jeg, tile_count=tile_count, position=position )
              if(mpp_file(unit)%write_on_this_pe .OR. .NOT. global_field_on_root_pe) then
                  allocate( gdata(isg:ieg,jsg:jeg,size(data,3),size(data,4)) )
              else
                  allocate( gdata(1,1,1,1))
              endif
              if(global_field_on_root_pe) then
                 call mpp_global_field( domain, data, gdata, position = position, &
                                        flags=XUPDATE+YUPDATE+GLOBAL_ROOT_ONLY, &
                                        default_data=default_data)
              else
                 call mpp_global_field( domain, data, gdata, position = position, &
                                        default_data=default_data)
              endif
!all non-0 PEs have passed their data to PE 0 and may now exit
              if(mpp_file(unit)%write_on_this_pe ) then
                 call write_record( unit, field, size(gdata(:,:,:,:)), gdata, tstamp)
              endif
              deallocate(gdata)
          end if
      else if(mpp_file(unit)%io_domain_exist ) then
          if( halos_are_global )then
              if(npes .GT. 1) call mpp_update_domains( data, domain, position = position )
              if(mpp_file(unit)%write_on_this_pe ) then
                 call write_record( unit, field, size(data(:,:,:,:)), data, tstamp)
              endif
          else
              io_domain=>mpp_get_io_domain(mpp_file(unit)%domain) 
              call mpp_get_global_domain ( io_domain, isg, ieg, jsg, jeg, tile_count=tile_count, position=position )
              if(mpp_file(unit)%write_on_this_pe .OR. .NOT. global_field_on_root_pe) then
                 allocate( gdata(isg:ieg,jsg:jeg,size(data,3),size(data,4)) )
              else
                 allocate( gdata(1,1,1,1))
              endif
              if(global_field_on_root_pe) then
                 call mpp_global_field( io_domain, data, gdata, position = position, &
                                        flags=XUPDATE+YUPDATE+GLOBAL_ROOT_ONLY,      &
                                        default_data=default_data)
              else
                 call mpp_global_field( io_domain, data, gdata, position = position, &
                                        default_data=default_data)
              endif
              io_domain => NULL()
              if(mpp_file(unit)%write_on_this_pe ) then
                 call write_record( unit, field, size(gdata(:,:,:,:)), gdata, tstamp)
              endif
              deallocate( gdata )
          endif
      else if( data_has_halos )then
!store compute domain as contiguous data and pass to write_record
          allocate( cdata(is:ie,js:je,size(data,3),size(data,4)) )
          cdata(:,:,:,:) = data(is-isd+1:ie-isd+1,js-jsd+1:je-jsd+1,:,:)
          call write_record( unit, field, size(cdata(:,:,:,:)), cdata, tstamp, domain, tile_count=tile_count ) 
      else
!data is already contiguous
          call write_record( unit, field, size(data(:,:,:,:)), data, tstamp, domain, tile_count=tile_count )
      end if

      call mpp_clock_end(mpp_write_clock)

      return
    end subroutine MPP_WRITE_2DDECOMP_4D_