Changes between Initial Version and Version 1 of PDAFomi_set_localize_covar


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Timestamp:
Mar 21, 2025, 2:34:45 PM (13 days ago)
Author:
lnerger
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  • PDAFomi_set_localize_covar

    v1 v1  
     1= PDAFomi_set_localize_covar =
     2
     3This page documents the routine `PDAFomi_set_localize_covar`` of PDAF-OMI, which are introduced with PDAF3.0.
     4
     5The routine has to be called in `init_dim_obs_OBSTYPE` in each observation module if the localized EnKF or the ENSRF/EAKF with localization are used. It initializes the information for covariance localization.
     6
     7||See the [wiki:OMI_observation_modules page describing PDAF-OMI observation modules] for the full documentation of OMI observation modules and the [wiki:ImplementAnalysislenkfOmi page on implementing the analysis step of the LEnKF] or the [wiki:ImplementAnalysisENSRFOmi page on implementing the analysis step of the ENSRF/EAKF] . ||
     8
     9The interface is for isotropic localization:
     10{{{
     11  SUBROUTINE PDAFomi_set_localize_covar(thisobs, dim, ncoords, coords, &
     12       locweight, cradius, sradius)
     13}}}
     14with arguments:
     15{{{
     16    TYPE(obs_f), INTENT(inout) :: thisobs       ! Data type with full observation
     17    INTEGER, INTENT(in) :: dim                  ! State dimension
     18    INTEGER, INTENT(in) :: ncoords              ! Number of coordinate directions
     19    REAL, INTENT(in)    :: coords(dim,ncoords)  ! Coordinates of state vector elements
     20    INTEGER, INTENT(in) :: locweight            ! Localization weight type
     21    REAL, INTENT(in)    :: cradius              ! localization radius
     22    REAL, INTENT(in)    :: sradius              ! Support radius for weight functions
     23}}}
     24
     25'''Notes:'''
     26 * The routine allows to specify the localization radius and support radius (`lradius`, `sradius`) and localization function (`locweight`) individually for each observation type.
     27 * The coordinate array `coords` specified the coordinates of each element in the state vector. The units have to be consistent with those used to specify the coordinates of observations.
     28 * The routine only supports a fixed localization radius throughout the domain.
     29 * One can also directly call the routine `PDAFomi_set_localize_covar_iso`, e.g. when calling from a program coded in C.
     30
     31
     32== `PDAFomi_set_localize_covar` for non-isotropic localization ==
     33
     34There is an alternative interface for non-isotropic localization. In this variant `cradius` and `sradius` are specified as vectors holding a value of localization radius for each coordinate direction. This permits for non-isotropic localization.
     35
     36{{{
     37  SUBROUTINE PDAFomi_set_localize_covar(thisobs, dim, ncoords, coords, &
     38       locweight, cradius, sradius)
     39}}}
     40with arguments:
     41{{{
     42    TYPE(obs_f), INTENT(inout) :: thisobs       ! Data type with full observation
     43    INTEGER, INTENT(in) :: dim                  ! State dimension
     44    INTEGER, INTENT(in) :: ncoords              ! Number of coordinate directions
     45    REAL, INTENT(in)    :: coords(dim,ncoords)  ! Coordinates of state vector elements
     46    INTEGER, INTENT(in) :: locweight            ! Localization weight type
     47    REAL, INTENT(in)    :: cradius(ncoords)     ! directional localization radii
     48    REAL, INTENT(in)    :: sradius(ncoords)     ! directional support radii for weight functions
     49}}}
     50
     51**Note:**
     52 * One can also directly call the routine `PDAFomi_set_localize_covar_noniso`, e.g. when calling from a program coded in C.
     53
     54
     55
     56
     57== `PDAFomi_set_localize_covar` for non-isotropic localization with different weight functions ==
     58
     59There is an alternative interface for non-isotropic localization which further allows to specify different weight functions for each direction. This allows, for example to use a constant weight in the vertical direction, but smoother decaying weight in the horizontal directions. In this variant `cradius` and `sradius` are specified as vectors holding a value of localization radius for each coordinate direction. In addition `locweight` is specified as a vector holding the localization function index for each coordinate direction.
     60
     61{{{
     62  SUBROUTINE PDAFomi_set_localize_covar(thisobs, dim, ncoords, coords, &
     63       locweight, cradius, sradius)
     64}}}
     65with arguments:
     66{{{
     67    TYPE(obs_f), INTENT(inout) :: thisobs       ! Data type with full observation
     68    INTEGER, INTENT(in) :: dim                  ! State dimension
     69    INTEGER, INTENT(in) :: ncoords              ! Number of coordinate directions
     70    REAL, INTENT(in)    :: coords(dim,ncoords)  ! Coordinates of state vector elements
     71    INTEGER, INTENT(in) :: locweight(ncoords)   ! directional localization weight types
     72    REAL, INTENT(in)    :: cradius(ncoords)     ! directional localization radii
     73    REAL, INTENT(in)    :: sradius(ncoords)     ! directional support radii for weight functions
     74}}}
     75
     76**Note:**
     77 * One can also directly call the routine `PDAFomi_set_localize_covar_noniso_locweights`, e.g. when calling from a program coded in C.