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ERA-Interim | ERA5 | ERA5-Land | |
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Period covered | 1979 - present | 1950 1940 - present | 1950 - present |
Production Period | August 2006 – 31st August 2019 | Jan 2016 – end 2017, then continued in near real-time | May 2018-July 2019 [1981-2019], then continued with 2-3 months delay wrt real time & Jan-Dec 2020 [1950-1980] |
Model version | IFS Cycle 31r2 | IFS Cycle 41r2 | Tiled ECMWF Scheme for Surface Exchanges over Land incorporating land surface hydrology (H-TESSEL) IFS Cycle 45r1 |
Assimilation system | IFS Cycle 31r2 4D-Var | IFS Cycle 41r2 4D-Var | n/a |
Spatial resolution | 79 km globally, 60 levels to 0.1 hPa | 31 km globally, 62km for the Ensemble of Data Assimilations (EDA), 137 levels to 0.01 hPa | 9km globally, 62 km from ERA5 EDA equivalent surface fields |
Output frequency (temporal resolution) | 6-hourly analysis fields Forecast fields on surface and pressure levels 3-hourly up to 24 hours, with reduced frequency up to 10 days | Hourly analysis fields, 3-hourly for the Ensemble of Data Assimilations (EDA) Hourly forecast fields, 3-hourly for the Ensemble of Data Assimilations (EDA), up to 18 hours, with reduced frequency up to 10 days (not in initial release) | Hourly fields for all variables |
Uncertainty estimates | None | From a 10-member Ensemble of Data Assimilations (EDA) at 63 km resolution | From ERA5-equivalent variables 10-member Ensemble of Data Assimilations (EDA) at 63 km resolution. |
Model input | As in operations (inconsistent SST) | Appropriate for climate (e.g. CMIP5 greenhouse gases, volcanic eruptions, SST and sea-ice cover) | Atmospheric forcing of ERA5 with additional lapse-rate correction |
Input observations | As in ERA-40 and from Global Telecommunication System | In addition, various newly reprocessed datasets and recent instruments that could not be ingested in ERA-Interim | Observations indirectly influence the simulation through the atmospheric forcing from ERA5. This forcing drives the ERA5-Land single simulation and it has been obtained by assimilating observations through a 4D-VAR data assimilation system and a Simplified Extended Kalman Filter |
Variational bias scheme | Satellite radiances | Also ozone, aircraft and surface pressure data | n/a |
Satellite data | RTTOV-7, clear-sky, 1D-VAR rainy radiances | RTTOV-11, all-sky for various components | n/a |
New parameters | ERA-Interim contains about 100 parameters on surface and single level alone, plus parameters on other level types. | ERA5 contains over 240 parameters on surface and single level alone, plus parameters on other level types. For specific parameters please compare the technical documentation linked below. | ERA5-Land contains finer-scale information of land surface component than ERA5, plus specific evaporation parameters. For specific parameters please compare the technical documentation linked below. |
Parameters removed | A few parameters present in ERA-Interim are not available in ERA5. For availability of specific parameters please see the technical documentation linked below. | Most of the atmospheric parameters and all the wave parameters present in ERA-5 are not available in ERA5-Land. For availability of specific parameters please see the technical documentation linked below. | |
Handling of accumulated parameters | Accumulated from the beginning of the forecast | Accumulated from previous post-processing | Accumulated from the beginning of the forecast |
Product main page | http://www.ecmwf.int/en/research/climate-reanalysis/era-interim | http://climate.copernicus.eu/climate-reanalysis | http://climate.copernicus.eu/climate-reanalysis |
Technical documentation | Berrisford et al 2011: The ERA-Interim archive Version 2.0 | ERA5 data documentation | ERA5-Land: data documentation |
Additional innovations | Long-term evolution of CO2 in RTTOV, cell-pressure correction SSU, improved bias correction for radiosondes, EDA perturbations for sea-ice cover |
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