ECMWF ERA-Interim - European Reanalysis

ERA Interim surface 00 6H 2 m T (variable 167) monthly mean — ECMWF ERA Interim reanalysis global surface 00 6H 2 m T (variable 167) monthly mean, Jan 1989. Copyright: UHH/CEN/AJB

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Access

RESTRICTED:

RESTRICTED: This link to the data set is only available for a restricted user group. The data set is only accessible in CEN/MPI net or accessible from external nets with a customer account. Please contact ICDC if you would like to access this data from outside the network.

Data access via file system: /data/icdc/reanalyses/era_interim/

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Description

The reanalysis dataset ERA-Interim is the predecessor of ERA-5 and the successor to ERA-40. ICDC offers a subset of the data for internal use.

ERA-Interim is a frequently used global atmospheric reanalysis produced by the European Center for Medium-Range Weather Forecasts (ECMWF). The ERA interim project was carried out to replace the previous atmospheric reanalyse ERA-40 in the long term. The data begin in 1979 and reanalysis is still ongoing. The forecasting model, data assimilation method and input data sets for ERA interim were described in the article mentioned in the references section below, where the performance of the system was discussed as well. In this re-analysis, several problems that were identified in ERA-40 were treated with improved methods, in particular the hydrological cycle, the quality of the stratospheric circulation and the temporal consistency of the analyzed fields. The number of atmospheric levels has been increased from 23 to 37 levels compared to ERA-40 and additional cloud parameters have been introduced. Please have a look at the mentioned licenses for information about usage restrictions.

Of the multitude of possible parameters and altitude levels, ICDC offers only a selection and only internally for registered users. The data has been obtained via the WDCC of the DKRZ. In the moment, data are offered from selected soil parameters, which can be understood as instantaneous values of the analysis step. The original data are available on the ECMWF site in GRIB format on a Gauss grid with the resolution N128. ICDC currently offers this data in NetCDF format on a regular Gaussian grid with a spatial resolution of about 0.7 ° and a temporal resolution of 6 hours for the period 1979 to 2018. Interpolation to a regular grid was abandoned to keep the data accuracy.

Last update of data set at ICDC:

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Parameters

Parameters of the ERA-Interim data set, currently available at ICDC. See also complete parameter list at the ECMWF
Name	Abbrev.	Variable number	Unit
Mean Sea Level Pressure	MSL	151	Pa
Sea ice cover /area fraction	CI	31	0-1
Snow density	RSN	33	kg/m³
Snow depth	SD	141	m
Temperature at 2m	2T	167	K
Total cloud cover	TCC	164	0-1
Total column water vapour	TCWV	137	kg/m2
U Wind component at 10m	10U	165	m/s
V Wind component at 10m	10V	166	m/s

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Coverage, spatial and temporal resolution

Period and temporal resolution:

1979-01-01 to 2018-31-12
6-hourly

Coverage and spatial resolution:

Global
Spatial resolution: approx. 0.7 ° x 0.7 °, latitude irregular (Gaussian grid)
Geographic longitude: 0.0 ° E to 359.30 ° E
Geographic latitude: -89.46 ° N to 89.46 ° N
Dimension: 512 columns x 256 rows
Altitudes: sfc

Format:

NetCDF

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Data quality

These are model data based on measured data. Possible sources of errors are faulty measured data that are assimilated into the model, as well as simplifications or even errors in the model. The quality of the data assimilation has been improved significantly compared to ERA40 and the model has a high quality. For details have a look on the project site at the ECMWF (see references).

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Contact

Annika Jahnke-Bornemann

ICDC / CEN / University of Hamburg
E-Mail: annika.jahnke-bornemann"AT"uni-hamburg.de

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References

Literature:

Simmons A, Uppala S,Dee D,Kobayashi S. 2006. ERA-Interim: New ECMWF reanalysis products from 1989 onwards. ECMWF Newsletter 110: 26–35. DOI 10.21957/pocnex23c6, http://dx.doi.org/10.21957/pocnex23c6
Dee DP et. al., 2011: The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q. J. R. Meteorol. Soc. 137: 553–597. DOI:10.1002/qj.828, https://doi.org/10.1002/qj.828
Berrisford, P., D. Dee, K. Fielding, M. Fuentes, P. Kallberg, S. Kobayashi and S. Uppala:The ERA-Interim archive, ERA Report Series, August 2009, https://www.ecmwf.int/en/elibrary/8173-era-interim-archive
Jakobson, E., Vihma, T., Palo, T., Jakobson, L., Keernik, H., and Jaagus, J. (2012), Validation of atmospheric reanalyses over the central Arctic Ocean, Geophys. Res. Lett., 39, L10802, doi:10.1029/2012GL051591. https://doi.org/10.1029/2012GL051591
Serreze, M. C., Barrett, A. P., and Stroeve, J. (2012), Recent changes in tropospheric water vapor over the Arctic as assessed from radiosondes and atmospheric reanalyses, J. Geophys. Res., 117, D10104, doi:10.1029/2011JD017421. https://doi.org/10.1029/2011JD017421

Websites:

ERA Interim project site at the ECMWF, https://www.ecmwf.int/en/forecasts/datasets/archive-datasets/reanalysis-datasets/era-interim

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Data citation, License, and Acknowledgments

Please cite the data as follows:

Simmons A, Uppala S,Dee D,Kobayashi S. 2006. ERA-Interim: New ECMWF reanalysis products from 1989 onwards. ECMWF Newsletter 110: 26–35. DOI 10.21957/pocnex23c6.

and with the following acknowledgments:

Thanks to ICDC, CEN, University of Hamburg for data support.

License

You can find license information on the ECMWF project page.

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