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How to convert GRIB2 data to netCDF data?
For the advanced users it is recommended to use the GRIB2 to NETCDF conversion table with the -nc_table sub-option or combine the command line options with instructions in the -nc_table conversion file. The -append option makes possible to create single large data set for long time series of gridded data.
Why is max number of vertical levels required in wgrib2?
It is the reason why the max_number_of_vertical_levels value must be provided by user. Grib2 types of vertical levels eligible for export to the netcdf as 4D data are defined in the wgrib2 internal table and now include next types of GRIB2 levels:
What do you need to know about GRIB2 levels?
Fields here include: 100 the grib2 level type code number for tre pressure short_name for the vertical axis in the pressure level long_name for the vertical axis in the n mb vertical axis units as written in the ne 0.01 decimal scale to convert grib2 level val
How are the grid values written in wgrib?
Default the grid values are written as 4 bytes float having {TIME,LAT,LON} dimension shape (3D data) and possible vertical LEV information added to the name of variables. For example, V wind component defined at 10 m level in atmosphere will have default name VGRD_10maboveground .
Is the netCDF file compatible with gradsnc?
The -nc_grads option activates some tests for the created netcdf file to be GrADS (version 1.9b4) compatible, or to be open by sdfopen in gradsnc or gradsdods. The GrADS support only COARDS convention netcdf files; it do not support non-constant data time stepping and silently generates wrong time stamps for such netcdf files.
How does the Climate Prediction Center-netCDF work?
The -netcdf option writes the grid values to a specified file in netcdf format using COARDS convention for the Latitude-Longitude, Mercator and Gaussian grids and the CF-1.0 convention for Lambert and Polar stereographic projection grids. Other grid templates and projections are not supported yet.
Is the time dimension of data in netCDF unlimited?
Time dimension of data in the netcdf file is “unlimited”, it could be extended “forward” when adding new data but not “backward” before the first defined time value. If data for the same time step already exist in the updated netcdf file these will be silently overwritten.