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Table 3.1: List of variables in the AgERA5 data set
Short name | Long name | Unit | Aggregation | AGROVOC URI |
Cloud_Cover_Mean | Total cloud cover (00-00LT) | (0 - 1) | Mean | |
Dew_Point_Temperature_2m_Mean | 2 meter dewpoint temperature (00-00LT) | K | Mean | |
Preciptation_Flux | Total precipitation (00-00LT) | mm d-1 | Sum | |
Preciptation_Rain_Duration_Fraction | Precipitation type duration - rain (00-00LT) | - | Count | |
Preciptation_Solid_Duration_Fraction | Precipitation type duration - solid fraction (no hail) composed of: precipitation types freezing rain (3), snow (5), wet snow (6), mixture of | - | Count | |
Relative_Humidity_2m_06h | Relative humidity at 06LT | % | - | |
Relative_Humidity_2m_09h | Relative humidity at 09LT | % | - | |
Relative_Humidity_2m_12h | Relative humidity at 12LT | % | - | |
Relative_Humidity_2m_15h | Relative humidity at 15LT | % | - | |
Relative_Humidity_2m_18h | Relative humidity at 18LT | % | - | |
Snow_Thickness_LWE_Mean | Snow liquid water equivalent (00-00LT) | cm of liquid water equivalent | Mean | |
Snow_Thickness_Mean | Snow depth (00-00LT) | cm snow | Mean | |
Solar_Radiation_Flux | Surface solar radiation downwards (00-00LT) | J m-2d-1 | Sum | |
Temperature_Air_2m_Max_24h | Maximum air temperature at 2 meter (00-00LT) | K | Maximum | |
Temperature_Air_2m_Max_Day_Time | Maximum air temperature at 2 meter (06-18LT) | K | Maximum | |
Temperature_Air_2m_Mean_24h | 2 meter air temperature (00-00LT) | K | Mean | |
Temperature_Air_2m_Mean_Day_Tim e |
| K | Mean | |
Temperature_Air_2m_Mean_Night_Ti me |
| K | Mean | |
Temperature_Air_2m_Min_24h | Minimum air temperature at 2 meter (00-00LT) | K | Minimum | |
Temperature_Air_2m_Min_Night_Time | Minimum air temperature at 2 meter (18-06LT) | K | Minimum | |
Vapour_Pressure_Mean | Vapour pressure (00-00LT) | hPa | Mean | |
Wind_Speed_10m_Mean | 10 meter wind component (00-00LT) | m s-1 | Mean |
Product target requirements
DATA DESCRIPTION | |
Horizontal coverage | Global (on a regular latitude-longitude grid) |
Temporal Coverage | 1 January 1979 to present |
Temporal resolution | Daily |
File format | NetCDF 4, Climate and Forecast (CF) Metadata Convention v1.6 |
Data type | Grid |
Horizontal resolution | 0.1° x 0.1° |
Some remarks related to the quality of the AgERA5 data set:
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The quality of the bias correction has been documented in a separate document named: "C3S422Lot1.WEnR.DS2_Downscaling and bias correction v1.7.pdf". For each of the 22 variables there are netCDFs available describing the performance of the bias correction in terms of the following sample statistics: MAE, RMSE, R-squared and bias:
- models_Cloud_Cover_Mean_Model2SelSeasonals_eval.nc
- models_Dew_Point_Temperature_2m_Mean_Model2SelSeasonals_eval.nc
- models_Relative_Humidity_2m_06h_Model2SelSeasonals_eval.nc
- models_Relative_Humidity_2m_09h_Model2SelSeasonals_eval.nc
- models_Relative_Humidity_2m_12h_Model2SelSeasonals_eval.nc
- models_Relative_Humidity_2m_15h_Model2SelSeasonals_eval.nc
- models_Relative_Humidity_2m_18h_Model2SelSeasonals_eval.nc
- models_Solar_Radiation_Flux_Model2SelSeasonals_eval.nc
- models_Temperature_Air_2m_Max_24h_Model2SelSeasonals_eval.nc
- models_Temperature_Air_2m_Max_Day_Time_Model2SelSeasonals_eval.nc
- models_Temperature_Air_2m_Mean_24h_Model2SelSeasonals_eval.nc
- models_Temperature_Air_2m_Mean_Day_Time_Model2SelSeasonals_eval.nc
- models_Temperature_Air_2m_Mean_Night_Time_Model2SelSeasonals_eval.nc
- models_Temperature_Air_2m_Min_24h_Model2SelSeasonals_eval.nc
- models_Temperature_Air_2m_Min_Night_Time_Model2SelSeasonals_eval.nc
- models_Vapour_Pressure_Mean_Model2SelSeasonals_eval.nc
- models_Wind_Speed_10m_Mean_Model2SelSeasonals_eval.nc
Overall, the temperature, humidity and wind speed variables benefit most from the correction. The MAE is reduced by 30% to 60% in the majority of cases. Grid points being located in mountainous areas or along coasts and lakes are improved most. This is not surprising as these are the areas where the largest systematic differences between ERA5 and HRES can be expected. But not only the relative improvements are quite large, also the absolute MAE values after the correction are small. The MAE for the 24h mean of the 2m temperatures (2t_davg) for example is for all continents below 0.72K, and for 4 of 6 continents even below 0.51K.
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