DESCRIPTION

Convert GRIB file(s) to netCDF format.

The only supported geometries for this feature are regular lat/lon grid or regular Gaussian (the key "typeOfGrid" should be "regular_ll" or "regular_gg")

If you are retrieving the data from our archive, check the following article for more information about how to obtain it interpolated to those grids by using the "grid" keyword: grid - keyword in MARS/Dissemination request

USAGE

grib_to_netcdf [options] -o output_file grib_file grib_file ...

OPTIONS


-I key1,key2,...

Ignore keys. Default method,type,stream,refdate,hdate


-S key1,key2,...

Split according to keys. Default param,expver


-R date

Reference date in the format YYYYMMDD. Default value 19000101.


-D NC_DATATYPE

Type of data. Possible values NC_BYTE, NC_SHORT, NC_INT, NC_FLOAT, NC_DOUBLE.
Default NC_SHORT


-T

Don't use time of validity.


-f

Force. Force the execution not to fail on error.


-o output_file

The name of the netCDF output file.


-V

Version.


-M

Multi-field support off. Turn off support for multiple fields in single GRIB message.


-k kind

Specifies the kind of file to be created. Possible values are:
1 -> netCDF classic file format
2 -> netCDF 64 bit classic file format (Default)
3 -> netCDF-4 file format
4 -> netCDF-4 classic model file format


-d level

Deflate data (compression level). Only for netCDF-4 output format. Possible values [0,9]. Default None. Chunking strategy based on GRIB message.


-s

Shuffle data before deflation compression.


-u dimension

Set dimension to be an unlimited dimension.

grib_to_netcdf examples

  1. Produce a NetCDF file from GRIB edition 1

    > grib_to_netcdf -o output.nc input.grib1


  2. If your grib file has analysis and 6-hour forecast, then ignore keys 'type' and 'step'. Thus type=an/fc and step=00/06 will not be considered as netCDF dimensions.

    > grib_to_netcdf -I type,step -o output.nc input.grib


  3. Do not use time of validity. If time of validity is used, it means the 1D time coordinate is considered as date+time+step, otherwise 3 different dimensions are created. The default behaviour is to use the time of validity.

    > grib_to_netcdf -T -o output.nc input.grib


  4. Produce netCDF with data type of FLOAT (32bit floating-point, for higher precision). Note these types were chosen to provide a reasonably wide range of trade-offs between data precision and number of bits required for each value

    > grib_to_netcdf -D NC_FLOAT -o output.nc input.grib


  5. Set the netCDF dimension 'time' to be unlimited i.e. time can have unlimited length so variables using this dimension can grow along this dimension.

    > grib_to_netcdf -u time -o output.nc input.grib