MODULE obs_readmdt !!====================================================================== !! *** MODULE obs_readmdt *** !! Observation diagnostics: Read the MDT for SLA data (skeleton for now) !!====================================================================== !! History : ! 2007-03 (K. Mogensen) Initial skeleton version !! ! 2007-04 (E. Remy) migration and improvement from OPAVAR !!---------------------------------------------------------------------- !!---------------------------------------------------------------------- !! obs_rea_mdt : Driver for reading MDT !! obs_offset_mdt : Remove the offset between the model MDT and the used one !!---------------------------------------------------------------------- USE par_kind ! Precision variables USE par_oce ! Domain parameters USE in_out_manager ! I/O manager USE obs_surf_def ! Surface observation definitions USE obs_inter_sup ! Interpolation support routines USE obs_inter_h2d ! 2D interpolation USE obs_utils ! Various observation tools USE iom_nf90 ! IOM NetCDF USE netcdf ! NetCDF library USE lib_mpp ! MPP library USE dom_oce, ONLY : & ! Domain variables & tmask, tmask_i, e1e2t, gphit, glamt USE obs_const, ONLY : obfillflt ! Fillvalue USE oce , ONLY : sshn ! Model variables IMPLICIT NONE PRIVATE PUBLIC obs_rea_mdt ! called by dia_obs_init PUBLIC obs_offset_mdt ! called by obs_rea_mdt INTEGER , PUBLIC :: nn_msshc = 1 ! MDT correction scheme REAL(wp), PUBLIC :: rn_mdtcorr = 1.61_wp ! User specified MDT correction REAL(wp), PUBLIC :: rn_mdtcutoff = 65.0_wp ! MDT cutoff for computed correction !!---------------------------------------------------------------------- !! NEMO/OCE 3.3 , NEMO Consortium (2010) !! $Id$ !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt) !!---------------------------------------------------------------------- CONTAINS SUBROUTINE obs_rea_mdt( sladata, k2dint ) !!--------------------------------------------------------------------- !! !! *** ROUTINE obs_rea_mdt *** !! !! ** Purpose : Read from file the MDT data (skeleton) !! !! ** Method : !! !! ** Action : !!---------------------------------------------------------------------- USE iom ! TYPE(obs_surf), INTENT(inout) :: sladata ! SLA data INTEGER , INTENT(in) :: k2dint ! ? ! CHARACTER(LEN=12), PARAMETER :: cpname = 'obs_rea_mdt' CHARACTER(LEN=20), PARAMETER :: mdtname = 'slaReferenceLevel.nc' INTEGER :: jobs ! Obs loop variable INTEGER :: jpimdt, jpjmdt ! Number of grid point in lat/lon for the MDT INTEGER :: iico, ijco ! Grid point indicies INTEGER :: i_nx_id, i_ny_id, i_file_id, i_var_id, i_stat INTEGER :: nummdt ! REAL(wp), DIMENSION(1) :: zext, zobsmask REAL(wp), DIMENSION(2,2,1) :: zweig ! REAL(wp), DIMENSION(:,:,:), ALLOCATABLE :: zmask, zmdtl, zglam, zgphi INTEGER , DIMENSION(:,:,:), ALLOCATABLE :: igrdi, igrdj ! REAL(wp), DIMENSION(jpi,jpj) :: z_mdt, mdtmask REAL(wp) :: zlam, zphi, zfill, zinfill ! local scalar !!---------------------------------------------------------------------- IF(lwp)WRITE(numout,*) IF(lwp)WRITE(numout,*) ' obs_rea_mdt : Read MDT for referencing altimeter anomalies' IF(lwp)WRITE(numout,*) ' ------------- ' CALL FLUSH(numout) CALL iom_open( mdtname, nummdt ) ! Open the file ! ! Get the MDT data CALL iom_get ( nummdt, jpdom_data, 'sossheig', z_mdt(:,:), 1 ) CALL iom_close(nummdt) ! Close the file ! Read in the fill value zinfill = 0.0 i_stat = nf90_open( mdtname, nf90_nowrite, nummdt ) i_stat = nf90_inq_varid( nummdt, 'sossheig', i_var_id ) i_stat = nf90_get_att( nummdt, i_var_id, "_FillValue",zinfill) zfill = zinfill i_stat = nf90_close( nummdt ) ! setup mask based on tmask and MDT mask ! set mask to 0 where the MDT is set to fillvalue WHERE(z_mdt(:,:) /= zfill) ; mdtmask(:,:) = tmask(:,:,1) ELSE WHERE ; mdtmask(:,:) = 0 END WHERE ! Remove the offset between the MDT used with the sla and the model MDT IF( nn_msshc == 1 .OR. nn_msshc == 2 ) & & CALL obs_offset_mdt( jpi, jpj, z_mdt, zfill ) ! Intepolate the MDT already on the model grid at the observation point ALLOCATE( & & igrdi(2,2,sladata%nsurf), & & igrdj(2,2,sladata%nsurf), & & zglam(2,2,sladata%nsurf), & & zgphi(2,2,sladata%nsurf), & & zmask(2,2,sladata%nsurf), & & zmdtl(2,2,sladata%nsurf) & & ) DO jobs = 1, sladata%nsurf igrdi(1,1,jobs) = sladata%mi(jobs)-1 igrdj(1,1,jobs) = sladata%mj(jobs)-1 igrdi(1,2,jobs) = sladata%mi(jobs)-1 igrdj(1,2,jobs) = sladata%mj(jobs) igrdi(2,1,jobs) = sladata%mi(jobs) igrdj(2,1,jobs) = sladata%mj(jobs)-1 igrdi(2,2,jobs) = sladata%mi(jobs) igrdj(2,2,jobs) = sladata%mj(jobs) END DO CALL obs_int_comm_2d( 2, 2, sladata%nsurf, jpi, jpj, igrdi, igrdj, glamt , zglam ) CALL obs_int_comm_2d( 2, 2, sladata%nsurf, jpi, jpj, igrdi, igrdj, gphit , zgphi ) CALL obs_int_comm_2d( 2, 2, sladata%nsurf, jpi, jpj, igrdi, igrdj, mdtmask, zmask ) CALL obs_int_comm_2d( 2, 2, sladata%nsurf, jpi, jpj, igrdi, igrdj, z_mdt , zmdtl ) DO jobs = 1, sladata%nsurf zlam = sladata%rlam(jobs) zphi = sladata%rphi(jobs) CALL obs_int_h2d_init( 1, 1, k2dint, zlam, zphi, & & zglam(:,:,jobs), zgphi(:,:,jobs), & & zmask(:,:,jobs), zweig, zobsmask ) CALL obs_int_h2d( 1, 1, zweig, zmdtl(:,:,jobs), zext ) sladata%rext(jobs,2) = zext(1) ! mark any masked data with a QC flag IF( zobsmask(1) == 0 ) sladata%nqc(jobs) = IBSET(sladata%nqc(jobs),15) END DO DEALLOCATE( & & igrdi, & & igrdj, & & zglam, & & zgphi, & & zmask, & & zmdtl & & ) IF(lwp)WRITE(numout,*) ' ------------- ' ! END SUBROUTINE obs_rea_mdt SUBROUTINE obs_offset_mdt( kpi, kpj, mdt, zfill ) !!--------------------------------------------------------------------- !! !! *** ROUTINE obs_offset_mdt *** !! !! ** Purpose : Compute a correction term for the MDT on the model grid !! !!!!! IF it is on the model grid !! !! ** Method : Compute the mean difference between the model and the !! used MDT and remove the offset. !! !! ** Action : !!---------------------------------------------------------------------- INTEGER, INTENT(IN) :: kpi, kpj REAL(wp), DIMENSION(kpi,kpj), INTENT(INOUT) :: mdt ! MDT used on the model grid REAL(wp) , INTENT(IN ) :: zfill ! INTEGER :: ji, jj REAL(wp) :: zdxdy, zarea, zeta1, zeta2, zcorr_mdt, zcorr_bcketa, zcorr ! local scalar REAL(wp), DIMENSION(jpi,jpj) :: zpromsk CHARACTER(LEN=14), PARAMETER :: cpname = 'obs_offset_mdt' !!---------------------------------------------------------------------- ! Initialize the local mask, for domain projection ! Also exclude mdt points which are set to missing data DO ji = 1, jpi DO jj = 1, jpj zpromsk(ji,jj) = tmask_i(ji,jj) IF ( ( gphit(ji,jj) .GT. rn_mdtcutoff ) & &.OR.( gphit(ji,jj) .LT. -rn_mdtcutoff ) & &.OR.( mdt(ji,jj) .EQ. zfill ) ) & & zpromsk(ji,jj) = 0.0 END DO END DO ! Compute MSSH mean over [0,360] x [-rn_mdtcutoff,rn_mdtcutoff] zarea = 0.0 zeta1 = 0.0 zeta2 = 0.0 DO jj = 1, jpj DO ji = 1, jpi zdxdy = e1e2t(ji,jj) * zpromsk(ji,jj) zarea = zarea + zdxdy zeta1 = zeta1 + mdt(ji,jj) * zdxdy zeta2 = zeta2 + sshn (ji,jj) * zdxdy END DO END DO IF( lk_mpp) CALL mpp_sum( zeta1 ) IF( lk_mpp) CALL mpp_sum( zeta2 ) IF( lk_mpp) CALL mpp_sum( zarea ) zcorr_mdt = zeta1 / zarea zcorr_bcketa = zeta2 / zarea ! Define correction term zcorr = zcorr_mdt - zcorr_bcketa ! Correct spatial mean of the MSSH IF( nn_msshc == 1 ) mdt(:,:) = mdt(:,:) - zcorr ! User defined value : 1.6 m for the Rio MDT compared to ORCA2 MDT IF( nn_msshc == 2 ) mdt(:,:) = mdt(:,:) - rn_mdtcorr IF(lwp) THEN WRITE(numout,*) WRITE(numout,*) ' obs_readmdt : rn_mdtcutoff = ', rn_mdtcutoff WRITE(numout,*) ' ----------- zcorr_mdt = ', zcorr_mdt WRITE(numout,*) ' zcorr_bcketa = ', zcorr_bcketa WRITE(numout,*) ' zcorr = ', zcorr WRITE(numout,*) ' nn_msshc = ', nn_msshc ENDIF IF ( nn_msshc == 0 ) WRITE(numout,*) ' MSSH correction is not applied' IF ( nn_msshc == 1 ) WRITE(numout,*) ' MSSH correction is applied' IF ( nn_msshc == 2 ) WRITE(numout,*) ' User defined MSSH correction' ! END SUBROUTINE obs_offset_mdt !!====================================================================== END MODULE obs_readmdt