Changes between Initial Version and Version 1 of PDAF_local_weights


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Timestamp:
Dec 21, 2016, 4:05:21 PM (9 years ago)
Author:
lnerger
Comment:

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  • PDAF_local_weights

    v1 v1  
     1= PDAF_local_weights =
     2
     3This page documents the routine `PDAF_local_weights` of PDAF.
     4
     5The routine is used for localization in the analysis step of a filter and computes weights according to the specified distances and the settings for the localizing function. The routine can be called in [wiki:prodRinvA_l_pdaf prodRinvA_l_pdaf] in the filters LESTKF, LETKF, and LSEIK. Also, the routine can be used for the LEnKF in the routine [localize_l_pdaf localize_l_pdaf].
     6
     7The interface is the following:
     8{{{
     9  SUBROUTINE PDAF_local_weight(wtype, cradius, sradius, distance, &
     10     nrows, ncols, weight, verbose)
     11}}}
     12with the following arguments:
     13 * `wtype` : `integer, intent(in)`[[BR]] Type of weight function:[[BR]] (0) unit weight (=1 up to radius `cradius`) [[BR]] (1) exponential decrease (1/e at distance=sradius; 0 for distance>cradius)[[BR]] (2) 5th order polynomial with support radius sradius (Gaspari&Cohn 1999; 0 for distance>sradius)
     14 * `cradius` : `real, intent(in)`[[BR]] Cut-off radius (weight is always =0 for distance>cradius)
     15 * `sradius` : `real, intent(in)`[[BR]] Support radius
     16 * `dim` : `integer, intent(in)`[[BR]] Size of arrays `distance` and `weights'
     17 * `distance` : `real, intent(in)`[[BR]] Distance to observation
     18 * `weights` : `real, intent(out)`[[BR]] computed localization weight
     19 * `verbose` : `integer, intent(in)`[[BR]] Verbosity flag
     20
     21Notes:
     22 * `PDAF_local_weights` does not support the regulated localization method (Nerger et al. ,Quarterly Journal of the Royal Meteorological Society, 138 (2012) 802-812; see [PublicationsandPresentations]). To use the regulated localization one has to use the alternative routine [wiki:PDAF_local_weight PDAF_local_weight].
     23
     24There are currently only examples of using `PDAF_local_weight`, but not `PDAF_local_weights`. The examples for `PDAF_local_weight` can be found in the files `prodrinva_l_pdaf.F90` in the tutorial cases. Another example is, e.g. provided in the Lorenz-96 test case (see /testsuite/src/lorenz96/prodrinva_local.F90).