ERA-CLIM and ERA-CLIM2 are two successive international research project in the area of climate reanalysis. Details: ERA-CLIM and ERA-CLIM2.

One of the outputs of these projects is the ERA Interim dataset, a global atmospheric reanalysis from 1979, continuously updated in near real time as new data becomes available.

Product description

•  The ERA Interim dataset contains atmospheric and surface parameters:
  • 6-hourly atmospheric fields on model levels, pressure levels, potential temperature and potential vorticity
  • 3-hourly surface fields and daily vertical integrals
  • Monthly averages of daily means

  • Synoptic monthly averages at 0 UTC, 6 UTC, 12 UTC, 18 UTC

• The temporal coverage is from 1 January 1979 to present
• The spatial coverage is global
• The spectral resolution is T255 (~80 km spatial resolution) on 60 vertical levels from the surface up to 0.1 hPa.

• The data assimilation system used to produce ERA-Interim is based on a 2006 release of the IFS (Cy31r2). The system includes a 4-dimensional variational analysis (4D-Var) with a 12-hour analysis window.

Parameters and download

For a list of fields (parameters) in ERA Interim and download see the ECMWF dataserver.

Note that we are aware of several quality issues with ERA-Interim data.

Further documentation

See Berrisford et al. (2011) for detailed documentation of the parameters in this dataset.

An open-access journal article describing the ERA-Interim reanalysis is available from the Quarterly Journal of the Royal Meteorological Society. Additional details of the modelling and data assimilation system used to produce ERA-Interim can be found in the IFS documentation (choose Cy31r1) .

Further detailed documentation on ERA Interim is available in the ECMWF eLibrary.