Download Era5 Data
Madison Rapelyea
ERA5 is the fifth generation ECMWF atmospheric reanalysis of the global climate covering the period from January 1940 to present. ERA5 is produced by the Copernicus Climate Change Service (C3S) at ECMWF.
ERA5 provides hourly estimates of a large number of atmospheric, land and oceanic climate variables. The data cover the Earth on a 31km grid and resolve the atmosphere using 137 levels from the surface up to a height of 80km. ERA5 includes information about uncertainties for all variables at reduced spatial and temporal resolutions.
The essential maintenance work planned on the Climate Data Store (CDS), the Atmosphere Data Store (ADS) and associated infrastructure for Thursday 3rd December from 17:00GMT has been cancelled due to technical issues in the preparation phase of the event. The maintenance session is to be rescheduled and an announcement will be posted in due course. For further queries please contact User Support: copernicu...@ecmwf.int.
ERA5-Land is a global land-surface dataset at 9 km resolution, consistent with atmospheric data from the ERA5 reanalysis from 1950 onward. Daily updates 5 days behind real time are available as well. ERA5-Land initial release data, i.e., data no more than three months behind real time, are called ERA5-Land-T.
The ERA5 Observation Feedback Archive is a database containing all observations assimilated in ERA5, together with supplementary information about the quality of those observations. The ERA5 Observation Feedback Archive will be accessible via the Climate Data Store in late 2019.
A regional reanalysis dataset for two subdomains of the Arctic was produced for the Copernicus Climate Change Service (C3S) by MET Norway and their partners. The reanalysis covers a more than 30 year period from September 1990 to present and it will be updated on a regular basis with near real time data. The reanalysis is performed with the HARMONIE-AROME numerical weather prediction system at 2.5 km horizontal resolution. The products of the reanalysis are available to the public through the Climate Data Store.
ERA5 represents 10 years of progress made in modelling and data assimilation since the production of ERA-Interim. The numerous improvements and advances are discussed in the Expert Guidance and the cited literature. Although this is an extraordinary and very widely used product, users still need to be aware of the limitations of reanalysis; the major one that non-physical trends and variability may be present in the record of some variables due to an undesired interplay between systematic model bias and changes in the observing system.
ERA5 contains a 3-hourly uncertainty estimate at half the resolution that indicates where and when ERA5 is dominated by observations and therefore likely trustworthy on the synoptic level and where it is more controlled by underlying physical model which, when the effect of systematic model error is limited can still provide information on low-frequency variability. The evolution of this uncertainty estimate illustrates the enormous improvement of the ingested observing system (and therefore the quality of ERA5) over time with only surface observations in the 1940s (mostly over the northern hemisphere), the availability of upper-air observations from the mid 1940s and the start of the availability of large numbers of satellite observations from the end of the 1970s.
Due to stratospheric temperature biases from the years 2000-2006 that were present in the first version of ERA5, ECMWF have published an improved dataset, ERA5.1 for these years, which should be used to replace ERA5 for stratospheric studies where the atmospheric mean state matters. Please see the Simmons et al (2020) reference for details. According to Simmons et al. 2020: "ERA5 and ERA5.1 perform very similarly in the lower and middle troposphere."
Integrator of large volumes of observations providing a spatially and temporally complete data set of multiple variables at high spatial (31km) and temporal (hourly) resolution. Produced in near real time with a latency of about 5 days.
More accurate representation of the actual historical atmospheric circulation, features like tropical cyclones, the hydrological cycle and energy budgets than previous generations of ECMWF reanalysis.
Availability of an uncertainty estimate from an Ensemble of Data Assimilation (EDA) Systems at half the resolution which guides when and where ERA5 is dominated by observations and when it more represents the model climate.
Several variables such as e.g., near-surface winds show (small) systematic jumps at 10UTC and 22UTC due to the design of the 12-hourly assimilation windows from which the time evolution of the hourly product is sampled.
ERA5 is the 5th major atmospheric reanalysis produced by ECMWF, following the FGGE reanalysis, ERA-15, ERA-40 and ERA-Interim. The ERA5 dataset provides hourly data on surface and upper-air parameters at roughly 31 km global resolution on 137 levels reaching up to 1 Pa. It also includes the 10 members from the ensemble 4D-Var data assimilation system used to produce the reanalysis, at reduced (3-hourly, 63 km) resolution.
ERA5 data are available from January 1940 onwards. Each day one new day is added that is 5 days behind real time. Data less than three months old can be changed in case large issues are found. So far, this has only occurred once in the fall of 2021 when poor quality control of snow observations from some stations in Central Asia had led to locally degraded 2m temperature and soil moisture. In that occasion the issue was resolved in time such that the final product was corrected within the given latency of three months.
ERA5 is a product of the Integrated Forecast System (IFS) release 41r2, which was operational at ECMWF during the period March-November 2016. This IFS release represents 10 years of progress on modelling and data assimilation at ECMWF since the production of ERA-Interim. Numerous model improvements were implemented during this time, many of them leading to major advances in the ability to assimilate satellite data in cloudy and rainy conditions. They include a complete overhaul of the radiation scheme, new treatment of large-scale clouds and precipitation, and the introduction of prognostic variables for precipitating rain and snow. Model boundary conditions and radiative forcing data compatible with CMIP5 recommendations were implemented to support climate reanalysis. These and many other advances relevant to reanalysis are documented in Hersbach et al. 2020, which also describes details of the design of the background error covariances used, observation quality control, bias correction schemes, an overview of all ingested observations and forcing datasets plus a basic evaluation of characteristics and performance.
Changes in the observing system and the production of segments in separate, parallel streams can result in unrealistic trends and variability in reanalysis data, especially where observation coverage is insufficient to constrain biases in the assimilating model. Figure 3 (from Bell et al., 2021) illustrates several unrealistic jumps in stratospheric temperature above 10 hPa. The low-frequency variability of temperature in the lower stratosphere and troposphere, however, does show the correct response to major volcanic eruptions in the lower stratosphere and evolution of the El Nio-Southern Oscillation (ENSO). The behaviour of upper-air ozone anomalies is quite different and purely model-based in the ERA before the availability of satellite observations, while jumps appear in stratospheric humidity at some transition points between production streams.
Some shifts in tropospheric humidity over oceans associated with the introduction of microwave imager data in the 1990s are still present in ERA5, although to a much lesser extent than in ERA-Interim.
The information provided by the 10-member ensemble 4D-Var can be useful as an indicator of state-dependent uncertainties but should be used with care. Preliminary analysis of spread-skill relationships suggest that the ensemble is generally under-dispersive, i.e,. the uncertainties tend to be underestimated.
ERA5 is the first reanalysis produced by ECMWF as an operational service rather than a research project. The development, production, data storage, data access and user support services for ERA5 are fully funded by the European Union under the Copernicus Earth Observation Programme. Climate reanalysis is a central element of the Copernicus Climate Change Service, which is implemented by ECMWF on behalf of the European Commission.
Incorporation within the Copernicus programme of reanalysis activities (including fundamental work on input observations) ensures sustainable development of future reanalyses as well as improved data access under free and open data policies.##
Analysis-Ready, Cloud Optimized (ARCO) ERA5 is the fifth generation of theEuropean Centre for Medium-Range Weather Forecasts (ECMWF)Atmospheric Reanalysis, providing hourly estimates of a large number ofatmospheric, land, and oceanic climate variables. The Google Cloud PublicDataset Program hosts ERA5 data that spans from 1940 toMay 2023, covering the Earth on a 30 km grid and resolves the atmosphereusing 137 levels from the surface up to a height of 80 km.
A reanalysis is the "most complete picture currently possible of past weatherand climate." Reanalyses are created from assimilation of a wide range of datasources via numerical weather prediction (NWP) models. Meteorologically valuablevariables for land and atmosphere were ingested and converted from grib data toZarr (with no other modifications) to surface a cloud-optimized version of ERA5.In addition, an open-sourced code base is provided to show theprovenance of the data as well as demonstrate common research workflows. Thisdataset includes both raw (grib) and cloud-optimized (zarr) files.
Thanks to the open data policy of the Copernicus Climate Change and AtmosphereMonitoring Services and ECMWF, this dataset is available free as part of theGoogle Cloud Public Dataset Program. Please see below for license information.
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