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Comparison table

This table highlights major differences between ERA-Interim, ERA5 and ERA5-Land. There are many additional differences, in particular changes to the computation of individual atmospheric parameters (due to the change in the assimilation system from 31r2 to 41r2) are not listed here.


ERA-InterimERA5ERA5-Land
Period covered1979 - present1950 - present1950 - present
Production PeriodAugust 2006 – 31st August 2019Jan 2016 – end 2017, then continued in near real-timeMay 2018-July 2019 [1981-2019], then continued with 2-3 months delay wrt real time & Jan-Dec 2020 [1950-1980]
Model versionIFS Cycle 31r2IFS Cycle 41r2Tiled ECMWF Scheme for Surface Exchanges over Land incorporating land surface hydrology (H-TESSEL) IFS Cycle 45r1
Assimilation systemIFS Cycle 31r2 4D-VarIFS Cycle 41r2 4D-Varn/a
Spatial resolution79 km globally, 60 levels to 0.1 hPa31 km globally, 62km for the Ensemble of Data Assimilations (EDA), 137 levels to 0.01 hPa9km 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 estimatesNoneFrom a 10-member Ensemble of Data Assimilations (EDA) at 63 km resolutionFrom ERA5-equivalent variables 10-member Ensemble of Data Assimilations (EDA) at 63 km resolution.
Model inputAs 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 observationsAs in ERA-40 and from Global Telecommunication SystemIn addition, various newly reprocessed datasets and recent instruments that could not be ingested in ERA-InterimObservations 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 schemeSatellite radiancesAlso ozone, aircraft and surface pressure datan/a
Satellite dataRTTOV-7, clear-sky, 1D-VAR rainy radiancesRTTOV-11, all-sky for various componentsn/a
New parametersERA-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 parametersAccumulated from the beginning of the forecast

Accumulated from previous post-processing

Accumulated from the beginning of the forecast
Product main pagehttp://www.ecmwf.int/en/research/climate-reanalysis/era-interimhttp://climate.copernicus.eu/climate-reanalysishttp://climate.copernicus.eu/climate-reanalysis
Technical documentationBerrisford et al 2011: The ERA-Interim archive Version 2.0ERA5 data documentationERA5-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


This document has been produced in the context of the Copernicus Climate Change Service (C3S).

The activities leading to these results have been contracted by the European Centre for Medium-Range Weather Forecasts, operator of C3S on behalf of the European Union (Delegation agreement signed on 11/11/2014). All information in this document is provided "as is" and no guarantee or warranty is given that the information is fit for any particular purpose.

The users thereof use the information at their sole risk and liability. For the avoidance of all doubt, the European Commission and the European Centre for Medium-Range Weather Forecasts have no liability in respect of this document, which is merely representing the author's view.