Introduction
The tables shown on this page summarize the list of variables requested to the providers of "Operational Products of Seasonal Forecasts" according to the invitation to tender C3S_330 (more info here)
This list includes some basic information for encoding those variables in netCDF. A more detailed information page about the encoding in netCDF will be found in the Guide to NetCDF encoding for C3S seasonal providers, 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
Static Data
GRIB | netCDF | |||
name | parameter ID | units | CF standard name | canonical units |
Land-sea mask | 172 | (0-1) | land_area_fraction | 1 |
Geopotential | 129 | m2 s-2 | surface_altitude | m |
Surface Fields
Sub-daily data
| 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) GRIB data streams could contain those variables as a composite field with parameter ID=139
Daily instantaneous data
| GRIB | netCDF | |||
time step | name | parameter ID | units | CF standard name | canonical units |
24h | Sea-ice cover | 31 | (0-1) | sea_ice_area_fraction | 1 |
24h | Volumetric soil water layer 1 (2) | 39 | m3 m-3 | moisture_content_of_soil_layer (2) | kg m-2 |
24h | Volumetric soil water layer 2 (2) | 40 | m3 m-3 | ||
24h | Volumetric soil water layer 3 (2) | 41 | m3 m-3 | ||
24h | Volumetric soil water layer 4 (2) | 42 | m3 m-3 | ||
24h | Snow depth | 141 | m of water equivalent | lwe_thickness_of_surface_snow_amount | m |
24h | Snow density | 33 | kg m-3 | snow_density | kg m-3 |
(2) soil water content should be provided for all native model levels (so 39-42 GRIB parameter IDs just apply to ECMWF/IFS soil model)
Daily time-aggregated data (accumulations, max/min,etc)
| GRIB | netCDF | |||
time step | name | parameter ID | units | CF standard name | canonical units |
24h | Maximum temperature at 2 metres in the last 24 hours | 51 | K | air_temperature | K |
24h | Minimum temperature at 2 metres in the last 24 hours | 52 | K | air_temperature | K |
24h | 10 metre wind gust since previous post-processing | 49 | m s-1 | wind_speed_of_gust | m s-1 |
24h | Large-scale precipitation (3) | 142 | m | lwe_thickness_of_stratiform_precipitation_amount (3) | m |
24h | Convective precipitation (3) | 143 | m | lwe_thickness_of_convective_precipitation_amount (3) | m |
24h | Total precipitation | 228 | m | lwe_thickness_of_precipitation_amount | m |
24h | Snowfall | 144 | m of water equivalent | lwe_thickness_of_snowfall_amount | m |
24h | Surface sensible heat flux | 146 | J m-2 | surface_upward_sensible_heat_flux | W m-2 |
24h | Surface latent heat flux | 147 | J m-2 | surface_upward_latent_heat_flux | W m-2 |
24h | Surface solar radiation downwards | 169 | J m-2 | surface_downwelling_shortwave_flux_in_air | W m-2 |
24h | Surface thermal radiation downwards | 175 | J m-2 | surface_downwelling_longwave_flux_in_air | W m-2 |
24h | Surface net solar radiation | 176 | J m-2 | surface_net_downward_shortwave_flux | W m-2 |
24h | Surface net thermal radiation | 177 | J m-2 | surface_net_downward_longwave_flux | W m-2 |
24h | Top net solar radiation | 178 | J m-2 | toa_net_downward_shortwave_flux | W m-2 |
24h | Top incoming solar radiation | 174089 | J m-2 | toa_incoming_shortwave_flux | W m-2 |
24h | Top net thermal radiation | 179 | J m-2 | toa_net_downward_longwave_flux | W m-2 |
24h | Eastward turbulent surface stress | 180 | N m-2 s | surface_downward_eastward_stress | Pa |
24h | Northward turbulent surface stress | 181 | N m-2 s | surface_downward_northward_stress | Pa |
24h | Evaporation | 182 | m of water equivalent | lwe_thickness_of_water_evaporation_amount | m |
24h | Runoff (4) | 205 | m | runoff_amount (4) | kg m-2 |
24h | Surface runoff | 8 | m | surface_runoff_amount | kg m-2 |
24h | Sub-surface runoff | 9 | m | subsurface_runoff_amount | kg m-2 |
(3) Large-scale and convective precipitation are not required if total precipitation is provided (and viceversa)
(4) Runoff is not required if both surface and sub-surface runoff are provided (and viceversa)
NOTES:
- Accumulations in GRIB are made from the beginning of the forecast, while in netCDF they are made accordingly to the description contained in the cell bounds/methods
- In netCDF, cell bounds and methods are also used to appropriately define maximum/minimum, etc.
Pressure Levels Fields
At the following 11 pressure levels (hPa): 925, 850, 700, 500, 400, 300, 200, 100, 50, 30 and 10
| GRIB | netCDF | |||
time step | name | parameter ID | units | CF standard name | canonical units |
12h | Geopotential | 129 | m2 s-2 | geopotential_height | m |
12h | Temperature | 130 | K | air_temperature | K |
12h | Specific humidity | 133 | kg kg-1 | specific_humidity | 1 |
12h | Vorticity (relative) (*) | 138 | s-1 | atmosphere_relative_vorticity (*) | s-1 |
12h | Divergence (*) | 155 | s-1 | divergence_of_wind (*) | s-1 |
12h | U component of wind | 131 | m s-1 | x_wind | m s-1 |
12h | V component of wind | 132 | m s-1 | y_wind | m s-1 |
(*) Vorticity and divergence are not required if U and V are provided (and viceversa)