subroutine da_setup_radiance_structures( grid, ob, iv )

   !---------------------------------------------------------------------------
   ! Purpose: Define, allocate and read of tovs raidance observation structure.
   !---------------------------------------------------------------------------

   implicit none

   type (domain) , intent(inout)   :: grid       ! model data
   type ( y_type), intent(inout)   :: ob         ! Observation structure.
   type (iv_type), intent(inout)   :: iv         ! O-B structure.

   character(len=200)          :: filename
   integer                     :: i, j, n, ios, ifgat
   logical                     :: lprinttovs 

   ! thinning variables
   integer  :: istart,iend,jstart,jend
   real     :: rlonlat(4)
   ! crtm_cloud
   integer  :: n1,n2,k,its,ite,jts,jte,kts,kte,inst
   
   if (trace_use) call da_trace_entry("da_setup_radiance_structures")

   !-------------------------------------------------------------------
   ! [1.0] Initialize RTTOV coefs and innovations vector for radiance
   !-------------------------------------------------------------------

    call da_radiance_init(iv, ob)
    
    do n = 1, rtminit_nsensor
       iv%instid(n)%rad_monitoring = rad_monitoring(n)
    enddo

   !-------------------------------
   ! 1.1 Make thinning grids
   !------------------------------
   call init_constants_derived

   if (thinning) then
      rlat_min =  r999
      rlat_max = -r999
      rlon_min =  r999
      rlon_max = -r999

      istart=MINVAL( grid%i_start(1:grid%num_tiles) )
      iend  =MAXVAL( grid%i_end  (1:grid%num_tiles) )
      jstart=MINVAL( grid%j_start(1:grid%num_tiles) )
      jend  =MAXVAL( grid%j_end  (1:grid%num_tiles) )

      do i = istart, iend
         do j = jstart, jend
            rlat_min=min(rlat_min, grid%xb%lat(i,j))
            rlat_max=max(rlat_max, grid%xb%lat(i,j))
            if( grid%xb%lon(i,j) < zero) then
              rlon_min=min(rlon_min, (r360+grid%xb%lon(i,j)))
              rlon_max=max(rlon_max, (r360+grid%xb%lon(i,j)))
            else
              rlon_min=min(rlon_min, grid%xb%lon(i,j))
              rlon_max=max(rlon_max, grid%xb%lon(i,j))
            endif
         enddo
      enddo

#ifdef DM_PARALLEL
      call mpi_reduce(rlat_min, rlonlat(1), 1, true_mpi_real, mpi_min, root, comm, ierr)
      call mpi_reduce(rlon_min, rlonlat(2), 1, true_mpi_real, mpi_min, root, comm, ierr)
      call mpi_reduce(rlat_max, rlonlat(3), 1, true_mpi_real, mpi_max, root, comm, ierr)
      call mpi_reduce(rlon_max, rlonlat(4), 1, true_mpi_real, mpi_max, root, comm, ierr)

      CALL mpi_bcast( rlonlat, 4 , true_mpi_real , root , comm, ierr )

      rlat_min = rlonlat(1)
      rlon_min = rlonlat(2)
      rlat_max = rlonlat(3)
      rlon_max = rlonlat(4)
#endif

      dlat_grid = rlat_max - rlat_min
      dlon_grid = rlon_max - rlon_min

      allocate(thinning_grid(iv%num_inst,num_fgat_time))
      do ifgat=1,num_fgat_time
         do n=1,iv%num_inst
            call makegrids (n,thinning_mesh(n),ifgat)
         end do
      end do 
   end if

   !-------------------------------------------------------------------
   ! [2.0] Read NCEP bufr tovs data in radiance innovations vector
   !-------------------------------------------------------------------

   if ( (.not. use_filtered_rad) .and. (.not. use_pseudo_rad) .and. (.not. use_simulated_rad) ) then

      if (use_hirs2obs) then
         write(unit=stdout,fmt='(a)') 'Reading radiance 1b data from hirs2.bufr'
         filename = 'hirs2 '
         call da_read_obs_bufrtovs ('hirs2', iv, filename)
      end if

      if (use_msuobs) then
         write(unit=stdout,fmt='(a)') 'Reading radiance 1b data from msu.bufr'
         filename = 'msu'
         call da_read_obs_bufrtovs ('msu  ', iv, filename)
      end if

      if (use_hirs3obs) then
         write(unit=stdout,fmt='(a)') 'Reading radiance 1b data from hirs3.bufr'
         filename = 'hirs3'
         call da_read_obs_bufrtovs('hirs3', iv, filename)
      end if

      if (use_amsuaobs) then
         write(unit=stdout,fmt='(a)') 'Reading radiance 1b data from amsua.bufr'
         filename = 'amsua'
         call da_read_obs_bufrtovs ('amsua', iv, filename)
      end if

      if (use_amsubobs) then
         write(unit=stdout,fmt='(a)') 'Reading radiance 1b data from amsub.bufr'
         filename = 'amsub'
         call da_read_obs_bufrtovs ('amsub', iv, filename)
      end if

      if (use_hirs4obs) then
         write(unit=stdout,fmt='(a)') 'Reading radiance 1b data from hirs4.bufr'
         filename = 'hirs4'
         call da_read_obs_bufrtovs('hirs4', iv, filename)
      end if

      if (use_mhsobs) then
         write(unit=stdout,fmt='(a)') 'Reading radiance 1b data from mhs.bufr'
         filename = 'mhs'
         call da_read_obs_bufrtovs('mhs  ', iv, filename)
      end if

      if (use_airsobs) then
         write(unit=stdout,fmt='(a)') 'Reading airs 1b data from airs.bufr'
         filename = 'airs'
         call da_read_obs_bufrairs ('airs     ',iv, filename)
      end if

      if (use_eos_amsuaobs) then
         write(unit=stdout,fmt='(a)') 'Reading eos_amsua 1b data from airs.bufr'
         filename = 'airs'
         call da_read_obs_bufrairs ('eos_amsua',iv, filename)
      end if

      if (use_hsbobs) then
         write(unit=stdout,fmt='(a)') 'Reading hsb 1b data from airs.bufr'
         filename = 'airs'
         call da_read_obs_bufrairs ('hsb      ',iv, filename)
      end if

      if (use_ssmisobs) then
         write(unit=stdout,fmt='(a)') 'Reading ssmis data from ssmis.bufr'
         filename = 'ssmis'
         call da_read_obs_bufrssmis ('ssmis    ',iv, filename)
      end if

   end if

   if ( use_filtered_rad ) then
      write(unit=stdout,fmt='(a)') 'Reading filtered radiance'
      call da_read_filtered_rad (iv)
   end if

   if ( use_simulated_rad ) then
      write(unit=stdout,fmt='(a)') 'Reading simulated radiance'
 

      call da_read_simulated_rad (iv)
 

   end if

   if ( use_pseudo_rad ) then
      write(unit=stdout,fmt='(a)') 'Reading pseudo radiance from namelist'    
  
      call da_read_pseudo_rad (iv)
   

   end if

   if (use_kma1dvar) then
      do i=1,rtminit_nsensor
         filename = ' '
         filename='kma1dvar-'//trim(iv%instid(i)%rttovid_string)//'.inv'
         write(unit=stdout,fmt='(a,a)')  ' Reading KMA 1dvar innovation from  ', filename
         call da_read_kma1dvar (i,iv, ob, filename)
      end do
   end if

   if (thinning) then
      do ifgat=1,num_fgat_time
           do n=1,iv%num_inst
              call destroygrids (n,ifgat)
           end do
      end do
      deallocate(thinning_grid)
   end if

   ! sorting obs into FGAT time bins

   call da_sort_rad(iv)


   !-----------------------------------------------------------------------------
   ! [3.0] create (smaller) ob structure:
   !-----------------------------------------------------------------------------

   if (.not. use_kma1dvar) then
      do i = 1,  ob % num_inst
         ob % instid(i) % num_rad = iv % instid(i) % num_rad
         if (ob % instid(i) % num_rad < 1) cycle
         allocate (ob % instid(i) % tb(ob % instid(i) % nchan,ob % instid(i)%num_rad))
         ob % instid(i) % tb(:,:) = iv % instid(i) % tb_inv(:,:)
      end do
   end if

! Calculate DT for Cloudy Radiance DA

   if (use_rad .and. crtm_cloud .and. .not. DT_cloud_model) then
      its = grid%xp % its
      ite = grid%xp % ite
      jts = grid%xp % jts
      jte = grid%xp % jte
      kts = grid%xp % kts
      kte = grid%xp % kte

      grid%xb%delt(its:ite,jts:jte,kts:kte) = 0.0

      do inst= 1, iv % num_inst
         do n=1,iv%instid(inst)%num_rad
	     i = int(iv%instid(inst)%info%i(1,n))
	     j = int(iv%instid(inst)%info%j(1,n))
   	     grid%xb%delt(i:i+1, j:j+1, kts:kte) = 1800.0
         end do
      end do
   endif


   if (trace_use) call da_trace_exit("da_setup_radiance_structures")

end subroutine da_setup_radiance_structures