ERA-Interim — LLMpedia

ERA-Interim
Name	ERA-Interim
Producer	European Centre for Medium-Range Weather Forecasts
Start	1979
End	2019
Temporal coverage	6-hourly, 3-hourly, hourly
Spatial resolution	~80 km (T255)

Contents

ERA-Interim

ERA-Interim was a global atmospheric reanalysis dataset produced by the European Centre for Medium-Range Weather Forecasts that provided consistent historical estimates of the state of the atmosphere from 1979 to 2019. It served as a core dataset for research in climatology, meteorology, oceanography, and hydrology, supporting studies by institutions such as the World Meteorological Organization, NASA, NOAA, and the Intergovernmental Panel on Climate Change. ERA-Interim underpinned analyses for projects like the Global Climate Observing System, the Coupled Model Intercomparison Project, and many national meteorological service assessments.

Overview

ERA-Interim was designed as a successor to earlier reanalyses to provide improved representation of atmospheric dynamics and composition for applications used by European Space Agency, Met Office, and National Center for Atmospheric Research researchers. The dataset combined observations from platforms including radiosonde, satellite, aircraft, ship, and buoy systems and was regularly updated and archived by ECMWF for use by agencies such as EUMETSAT, JAXA, and CSIRO. ERA-Interim outputs informed operational forecasting at centers like Deutscher Wetterdienst, Météo-France, and Servicio Meteorológico Nacional (Argentina) and were cited in analyses by the United Nations Environment Programme and regional programs like Copernicus.

Development of ERA-Interim involved collaboration among agencies including ECMWF, EUMETSAT, WMO, and research groups from University of Reading, University of Exeter, and Max Planck Institute for Meteorology. Observation streams assimilated comprised instruments and networks such as Argos (satellite system), Advanced Very High Resolution Radiometer, Global Climate Observing System, Upper-air soundings, and Aircraft Meteorological Data Relay. Assimilation incorporated retrievals and radiance measurements from missions like NOAA-15, METOP-A, ERS-2, Envisat, and TRMM. Surface analyses used data from networks operated by National Oceanic and Atmospheric Administration, UK Met Office Hadley Centre, and regional services including Australian Bureau of Meteorology and Météo Suisse.

The ERA-Interim system employed a 4-dimensional variational data assimilation (4D-Var) framework implemented on the ECMWF Integrated Forecasting System, building on techniques developed with contributions from Lyndon State University researchers, the European Space Agency algorithm teams, and groups at Princeton University. Model physics included parameterizations influenced by work at Colorado State University, NCAR, and Lamont–Doherty Earth Observatory, with treatment of radiation, convection, and boundary layer processes tested against datasets from ARM Climate Research Facility and Global Precipitation Climatology Project. The assimilation system accounted for observation error covariances, background error statistics, and used variational bias correction for satellite radiances as advanced by teams from University of Oxford and ETH Zurich.

ERA-Interim produced a suite of gridded products: three-dimensional atmospheric fields (temperature, wind, humidity), surface fluxes, precipitation, soil moisture, and wave parameters used by groups like European Commission maritime services and International Maritime Organization analysts. Outputs were archived on Gaussian grids and pressure levels, with derived diagnostics useful to researchers at Scripps Institution of Oceanography, Woods Hole Oceanographic Institution, and Potsdam Institute for Climate Impact Research. Versions included periodic upgrades in model cycle and observation handling coordinated with releases by ECMWF and documented in workshops attended by representatives from NOAA National Centers for Environmental Prediction and NASA Goddard Space Flight Center.

Validation of ERA-Interim involved intercomparisons with reanalyses such as NCEP/NCAR Reanalysis, JRA-55, and regional products from CFSR and analyses by Met Office Hadley Centre. Performance assessments used independent datasets from GRACE, Argo, CALIPSO, and surface networks operated by Icelandic Meteorological Office and Japan Meteorological Agency. Studies by researchers at University of Colorado Boulder and University of Reading demonstrated strengths in representing midlatitude circulation and issues in polar surface temperatures and precipitation when compared with observations from Antarctic research stations and Greenland campaigns. ERA-Interim was widely cited in evaluations for the IPCC Fifth Assessment Report and in basin-scale hydrological studies by institutions like International Institute for Applied Systems Analysis.

ERA-Interim was succeeded by ERA5, developed under programs led by ECMWF in partnership with the Copernicus Climate Change Service and European Union. The transition incorporated higher-resolution modeling and reprocessing of observation streams from missions such as Sentinel-3, Jason-3, and upgraded assimilated radiances from MetOp series, reflecting methodology advances contributed by groups at Universität Hamburg and IMAU (Institute for Marine and Atmospheric Research Utrecht). Users were advised by ECMWF and partners including Copernicus to migrate to ERA5 for improved temporal and spatial fidelity in applications by NASA, NOAA, and national research agencies.

Category:Reanalysis datasets