ECMWF Reanalysis Products

Note

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ERA ('ECMWF Re-Analysis') refers to a series of climate reanalysis datasets produced at the Europen Centre for Medium-Range Weather Forecasts (ECMWF). Climate reanalyses combine observations with models to generatÏe consistent time series of multiple climate variables. Reanalysis time series are widely used as forcing fields in atmospheric models. ERA5 (ERA fifth generation) is the latest climate reanalysis which is produced by Copernicus Climate Change Service (C3S) at ECMWF. It replaces ERA-Interim and other predecessor ERA datasets such as, e.g., ERA-40, ERA-15 and ERA-20C.

The ERA5 data of lower stratospheric temperature exhibit a pronounced cold bias for the years from 2000 to 2006 (see Simmons et al., 2020. For this reason, ERA5.1, an improved re-run of ERA5 for the years 2000 to 2006, was produced.

As a service to DKRZ users, DKRZ makes ERA5 and ERA5.1 data available on the HPC systems mistral and levante (in GRIB format). Users can access them via /pool/data/ERA5. That directory contains the ERA5 time series starting from January 1979. DKRZ staff regularly updates the available time series to extend them forward in time. Updates typically lag 3 months behind real time. The current state of the ERA5 data transfer can be monitored via https://modvis.dkrz.de/bm0146/ERA5/statusE5.html.

ERA5 data are available as pure analysis and as forecast. This is indicated by the forecast step. Step 0 refers to the analysis while any number exceeding zero refers to the number of hours the forecast has proceeded. For the ERA5 forecasts, the forecast steps 03, 06, 09 and 12 are available, but only step 12 is provided via /pool/data/ERA5.

Subdirectories of /pool/data/ERA5

directory name

description

sf00_1H, sf00_1D, sf00_MM

contain surface (sf) level ERA5 analysis data (forecast step 00) with hourly (1H), daily (1D) or monthly (MM) temporal resolution

sf12_1H, sf12_1D, sf12_MM

contain surface (sf) level ERA5 forecasts data (forecast step 12) with hourly (1H), daily (1D) or monthly (MM) temporal resolution

pl00_1H, pl00_1D,

contain ERA5 analysis data (forecast step 00) at the pressure level (pl) with hourly (1H) and daily (1D) temporal resolution

ml00_1H

contain ERA5 analysis data (forecast step 00) at model level (ml) with hourly (1H) resolution

ERA5 files on /pool/data/ERA5 have the following file naming convention:

\${product}\${directory_name}\_\${date}\_\${param}\

product is an acronym for the different ERA products:

E5 = ERA5; E1 = ERA5.1; ET = ERA5T; EB = ERA5 BE

date

  • \${YYYY}-\${MM}-\${DD} 1H data at ml and ml level (hourly ERA5 data)

  • \${YYYY}-\${MM} 1H data at sf level (hourly ERA5 data)

  • \${YYYY} 1D data (daily means of ERA5 hourly data)

  • \${YYYYS}-\${YYYYE} MM data (monthly means of ERA5 daily means)

(YYYY = 4-digit year; MM = two-digit month; DD = 2-digit day; YYYYS-YYYYE refer to the start and end years of a decade)

param refers to the last three digits of the parameter ID specified in ECMWF code table 128, except for param values >= 256 which refer to ECMWF code table 228. param = 000 is used for files which contain several parameters.

For more information, please refer to the README files in /pool/data/ERA5 and the individual subdirectories.

ERA5.1 shows significant differences to ERA5 only in the upper troposphere/stratosphere and only for certain variables. Therefore, solely a subset of ERA5.1 data is provided via /pool/data/ERA5, namely only hourly ERA5.1 analysis data on model levels (in subdirectory ml00_1H) and on pressure levels (in subdirectory pl00_1H). The file names of ERA5.1 data start with E1 (in contrast to E5 for ERA5 data) and are stored in separate monthly subfolders named \${MM}-era5.1.

ERA5T is a provisional, early-release version of the ERA5 data. ECMWF produces ERA5T with a 5-day delay from real time, i.e. with much less delay compared to the 2-3 months for the release of the final, validated ERA5 data. ERA5T is superseded once the validated ERA5 data become available. You find ERA5T data on /pool/data/E5 in the subdirectories sf00_1H, ml00_1H, sf00_1H, sf12_1H. ERA5T files are being deleted whenever the corresponding ERA5 files are made available on /pool/data/ERA5. Please be aware of the preliminary nature of the ERA5 BE data!

In addition to holding ERA5 data on mistral’s and levante’s /pool/data directory, DKRZ distributes the following ERA datasets via the WDCC data repository

ERA-Interim: https://cera-www.dkrz.de/WDCC/ui/cerasearch/project?acronym=ERA_INTERIM

ERA-40: https://cera-www.dkrz.de/WDCC/ui/cerasearch/project?acronym=ERA40

ERA-15: https://cera-www.dkrz.de/WDCC/ui/cerasearch/project?acronym=ERA15

ERA-20C: https://cera-www.dkrz.de/WDCC/ui/cerasearch/project?acronym=ERA-20C

In case you do not find the ERA data that you need, please contact data(at)dkrz.de. Please also contact us if you require specific ERA data in the /pool/data directory.

Further Information on ERA Data

More detailed information on the data can be found at:

How to Use and Correctly Cite ERA5 Data?

  • The EU-funded ERA5 data are not subject to any particular access restriction. Similarly, there are no concerns regarding the transfer of the data, however, please make sure that you cite the data correctly.

For ERA5 hourly and daily data at surface level:

Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J-N. (2018): ERA5 hourly data on single levels from 1979 to present, Copernicus Climate Change Service (C3S) Climate Data Store (CDS). 10.24381/cds.adbb2d47, accessed at DKRZ on <DD-MMM-YYYY>

For ERA5 hourly and daily data at pressure or model levels:

Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J-N. (2018): ERA5 hourly data on pressure levels from 1979 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). 10.24381/cds.bd0915c6, accessed at DKRZ on <DD-MMM-YYYY>

For ERA5 monthly averaged data at surface level:

Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J-N. (2019): ERA5 monthly averaged data on single levels from 1979 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). 10.24381/cds.f17050d7, accessed at DKRZ on <DD-MMM-YYYY>

For ERA5 monthly averaged data at pressure or levels:

Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J-N. (2019): ERA5 monthly averaged data on pressure levels from 1979 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). 10.24381/cds.6860a573, accessed at DKRZ on <DD-MMM-YYYY>