tools

Last update: 23 July 2003

Interpolation routines

For ELDAS source code is developed for interpolating rotated lat/lon fields to regular lat/lon and vice versa.
Two packages are developed: one using the ASIMOF GRIB-format used in the HIRLAM consortium, plus the EMOSLIB package from ECMWF, and one that can read/write ECMWF GRIB independent from ASIMOF libraries.

For both packages rotated and regular lat/lon grids can be used either as input or destination grid. A sequence of input files can be specified, allowing to overlay datafiles and background fields. The order of input files given on the command line determines the order of the interpolation process: coarse resolution, large domain background fields are normally given first, fine resolution smaller domain data files are given latest. Grib codes describing the output grid are taken from the destination grid file, remaining grib codes are normally taken from the latest input file. Command line options also allow to toggle between closest gridpoint/bicubic interpolation, and preserving land/sea masks in the interpolation process.

The list below provides links to source codes that are available. Please contact me when additional source code or information is required.

ASIMOF-package

Main code: intp_eldas.F
interpolation routine: bicubic.F
closest gridpoint selection: closest.F
makefile: Makefile and config.linux

GRIB-only package

gzipped tarfile with all code and makefile: interp.tar.gz
an example gribbing programme from VUW