PDAF_local_weight

This page documents the routine PDAF_local_weight of PDAF.

The routine is used for localization in the analysis step of a filter and computes a weight according to the specified distance and the settings for the localizing function.

The interface is the following:

  SUBROUTINE PDAF_local_weight(wtype, rtype, cradius, sradius, distance, &
     nrows, ncols, A, var_obs, weight, verbose)

with the following arguments:

• wtype : integer, intent(in)
  Type of weight function:
  (0) unit weight (=1 up to radius cradius)
  (1) exponential decrease (1/e at distance=sradius; 0 for distance>cradius)
  (2) 5th order polynomial with support radius sradius (Gaspari&Cohn 1999; 0 for distance>sradius)
• rtype : integer, intent(in)
  Type of regulated weighting:
  (0) no regulation
  (1) regulation using mean variances
  (2) regulation using variance of single observation point
• cradius : real, intent(in)
  Cut-off radius (weight is always =0 for distance>cradius)
• sradius : real, intent(in)
  Support radius
• distance : real, intent(in)
  Distance to observation
• nrows : integer, intent(in)
  Number of rows in matrix A
• ncols : integer, intent(in)
  Number of columns in matrix A
• A : real, intent(in), dimension(nrows,ncols)
  Input matrix (only used for regulated localization)
• var_obs : real, intent(in)
  Observation variance (only used for regulated localization)
• weight : real, intent(out)
  computed localization weight
• verbose : integer, intent(in)
  Verbosity flag