Introduction
The starting point for this work was tables shown on this page summarize the list of parameters variables requested in the ITT (see here). An in-depth review of this list was performed, and some modifications were proposed to the different providers to C3S seasonal activity (ECMWF, Met Office, MeteoFrance, DWD and CMCC). Additionally, it was recognised that the original list of parameters was (to a certain extent) incomplete, as it just used GRIB parameter codes to describe the variables. This was an issue, as most of the data providers are currently using (or will do in the near future) netCDF format for the files they will supply to C3S.to the providers of "Operational Products of Seasonal Forecasts" according to the invitation to tender C3S_330 (more info here)
This list Taking all of that into account, a revisited list of parameters to be used by the seasonal forecasting providers has been summarized in the tables below. This includes some basic information for encoding both those variables in GRIB and netCDF. A more detailed information page about the encoding in netCDF will be found in the Guide to NetCDF encoding for C3S seasonal providers, and this page which should be considered the definitive specification for the data encoding of the files to be provided.
Note that alongside the basic encoding information in netCDF, i.e. CF standard name and canonical units, the tables contain some details about GRIB encoding for the sake of comparability with previous C3S seasonal forecast datasets were provision in GRIB format was considered.
Requested variables from providers
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| GRIB | netCDF | |||
time step | name | parameter ID | units | CF standard name | canonical units |
6h | 2 metre temperature | 167 | K | air_temperature | K |
6h | 2 metre dewpoint temperature | 168 | K | dew_point_temperature | K |
6h | 10 metre U wind component | 165 | m s-1 | x_wind | m s-1 |
6h | 10 metre V wind component | 166 | m s-1 | y_wind | m s-1 |
6h | Mean sea level pressure | 151 | Pa | air_pressure_at_sea_level | Pa |
6h | Total cloud cover | 164 | (0-1) | cloud_area_fraction | 1 |
6h | Soil temperature level 1 | 139 | K | soil_temperature | K |
6h | Sea surface temperature (1) | 34 | K | sea_surface_temperature | K |
6h | Sea ice temperature (1) | 500172 | K | sea_ice_temperature | K |
(1) For GRIB data streams , could contain those variables can be included as a composite field with parameter ID=139
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