FLEXPART Model/Grib2

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• • Converting to the Grib2 format**

Grib2 has one main advantage: The data format allows for jpeg2000 compression, which makes files about 40% smaller, which in turn reduces download times and network traffic.

- Here is `a table <http://www.nco.ncep.noaa.gov/pmb/docs/grib2/GRIB2_parmeter_conversion_table.html>`_ which describes the conversion between GFS Grib1 and Grib2 codes.

- The `GFS data <http://www.nco.ncep.noaa.gov/pmb/products/gfs/gfsinfo_00z.shtml>`_ are available in three separate files:

1. analysis run (267 parameters but no surface fields), the 00h forecast data (286 parameters including the surface fields, but without precipitation), the >00h forecast data (329 parameters, including fluxes, cloud cover and precipitation rates)

2. surface forecast data, also for 00h (64 parameters, including fluxes, cloud cover and precipitation rates)

3. station-like surface data (4 parameters: T2M, RH2M, U10M, V10M)

The future aim is to convert also the already downloaded ECMWF data to Grib2 format. This should be doable with the grib_convert tool. However, as there are a number of custom fields in these files, some conversion tables have to be created. It still has to be figured out how to do that.

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