Step-by-step guide

It is often the case that users wish to reduce the number of observations from very high resolution sources so they may choose to skip a certain number of subsets from a BUFR message. This can now be achieved with the following keys (for compressed data):

  • simpleThinningSkip
  • doSimpleThinning

To explain the use of these keys the following example using bufr_filter is provided, but please note that these same keys can be set using the Fortran and Python interfaces as well and no special functions have been implemented in the bufr_filter for this feature.

The following file "thin.filter" with bufr_filter can be used to perform the thinning of subsets from a BUFR message:

thin.filter
set unpack=1;
set simpleThinningSkip=36;
set doSimpleThinning=1;

write;

Here we apply simple thinning to satellite data to skip 36 subsets i.e. the output BUFR message will have subset number 1, number 37, number 73 etc of the original message and the rest are skipped.

This example can be used on any multi-subset input file in compressed form as follows:

% bufr_filter -o out.bufr thin.filter in.bufr