wiki:PDAFomi_get_interp_coeff_tri

Version 1 (modified by lnerger, 10 months ago) (diff)

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PDAFomi_get_interp_coeff_tri

This page documents the routine PDAFomi_get_interp_coeff_tri of PDAF-OMI.

The routine is called in `init_dim_obs_OBSTYPE of an obseration module to initialize interpolation coefficients for triangular interpolation with barycentric coordinates. It is used if the observation operator performs linear interpolation (usually PDAFomi_obs_op_interp_lin).

See the page describing PDAF-OMI observation operators for a general overview.

The interface is:

  SUBROUTINE PDAFomi_get_interp_coeff_tri(gcoords, ocoords, icoeff)

    REAL, INTENT(in)    :: gcoords(:,:)  ! Coordinates of grid points; dim(3,2)
                                         !     3 rows; each containing lon and lat coordinates
    REAL, INTENT(in)    :: ocoords(:)    ! Coordinates of observation; dim(2)
    REAL, INTENT(inout) :: icoeff(:)     ! Interpolation coefficients; dim(3)

Note:

  • In the array gcoords, the first index specifies the grid point while the second specifies the coordinate, thus gcoords(1,1) is the first coordinate for grid point 1, gcoords(1,2) is the second coordiate for grid point 1, while gcoords(2,1) is the first coordiate for grid point 2. The coordinates need to be consistent with the indices specified in thisobs%id_obs_p since these specify the elements of the state vector that are interpolated. Only the first n_dim entries of ocoord will be used for the interpolation.