ERA Interim is the name of a global atmospheric reanalysis project at ECMWF, processing data from 1979 to date. ERA Interim is one of several ERA projects with similar scope carried out at ECMWF.

The ERA Interim project produces a single dataset, referred to as ERA Interim dataset. The ERA Interim dataset is continuously updated in near real time as new data becomes available.

Product description

•  The 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.