ERA5

ERA5
Name	ERA5
Producer	European Centre for Medium-Range Weather Forecasts
First release	2019
Temporal coverage	1950–present
Spatial resolution	~31 km (0.25°)
Variables	atmosphere, land, cryosphere
Access	Copernicus Climate Change Service

ERA5 is a global reanalysis dataset produced by the European Centre for Medium-Range Weather Forecasts under the Copernicus programme and provided through the Copernicus Climate Change Service. It supersedes earlier reanalyses by offering higher spatial resolution, finer temporal sampling, and extended variable sets spanning atmosphere, land, and cryosphere records. ERA5 supports climate monitoring, weather forecasting research, and operational applications used by institutions such as the World Meteorological Organization, National Aeronautics and Space Administration, and European Space Agency.

Overview

ERA5 combines past and present observations with numerical weather prediction produced by the Integrated Forecasting System at the European Centre for Medium-Range Weather Forecasts to create a physically consistent dataset. The project relates to predecessor efforts including ERA-Interim, NCEP/NCAR Reanalysis, and JRA-55, aiming to improve representation of processes studied by groups at the Met Office, National Oceanic and Atmospheric Administration, and university research centers such as ETH Zurich and Massachusetts Institute of Technology. ERA5 output underpins assessments used by panels like the Intergovernmental Panel on Climate Change and programs like the Global Climate Observing System.

Data and Variables

ERA5 provides hourly, sub-daily, and monthly fields for a broad suite of variables including three-dimensional atmospheric state, surface fluxes, soil moisture, and snow parameters. Standard variables support analyses comparable with datasets from MODIS, GRACE, Landsat, and Sentinel missions, and include temperature, humidity, wind components, geopotential height, precipitation, radiation, and sea-level pressure. Cryospheric variables align with observations from CryoSat, ICESat-2, and in situ networks such as Global Terrestrial Network for Hydrology, while land variables serve assimilation systems used by agencies like Food and Agriculture Organization and United Nations Environment Programme.

Production and Methodology

ERA5 production uses four-dimensional variational data assimilation and ensemble techniques implemented in the Integrated Forecasting System, ingesting observations from satellites (e.g., METOP, Suomi NPP), radio occultation missions (e.g., COSMIC), surface synoptic networks such as World Meteorological Organization stations, and upper-air radiosonde networks. Model physics improvements reflect research from institutions including ECMWF, Max Planck Institute for Meteorology, and Laboratoire de Météorologie Dynamique. Reprocessing workflows incorporate calibration and bias-correction steps used by teams at European Commission services and partner projects such as Copernicus Climate Change Service reanalysis initiatives. Compute-intensive production leverages supercomputing centers like PRACE facilities and national infrastructures exemplified by Jülich Supercomputing Centre.

Validation and Accuracy

Validation of ERA5 draws on independent datasets and intercomparison exercises with ERA-Interim, JRA-55, and MERRA-2 to assess biases, root-mean-square error, and representation of extremes. Studies published in journals involving researchers from University of Reading, National Center for Atmospheric Research, and University of Cambridge evaluate performance for temperature, precipitation, wind, and radiation against networks such as GCOS reference networks and satellite retrievals from NOAA and EUMETSAT. Uncertainty quantification uses ensemble members and comparison with reanalyses used by the Global Energy and Water Exchanges Project and climate assessment teams in regional studies for European Union policy and UNFCCC reporting.

Applications

ERA5 is used across sectors: climate research at institutions like Potsdam Institute for Climate Impact Research, renewable energy planning by companies and agencies collaborating with International Renewable Energy Agency, hydrology and flood modeling in projects linked to European Flood Awareness System, and urban climate studies at universities such as UCL and University of Melbourne. Operational users include aviation meteorology services at Eurocontrol and oceanography centers relying on coupling with systems such as Copernicus Marine Environment Monitoring Service. ERA5 inputs feed impact assessments by organizations like World Bank and adaptation planning within UNDP programs.

Access and Dissemination

ERA5 data are disseminated through the Copernicus Climate Data Store with APIs and services used by researchers at Google, cloud platforms operated by Amazon Web Services and Microsoft Azure, and portals maintained by the ECMWF. Training, documentation, and user support involve collaborations with academic consortia such as IS-ENES and capacity-building initiatives led by World Meteorological Organization and United Nations University. Data licensing and stewardship align with principles promoted by Committee on Earth Observation Satellites and international data infrastructures like GEOSS.

Category:Reanalysis datasets Category:Copernicus Programme