The ECMWF Re-Analysis (ERA40) is a global atmospheric analysis of many conventional observations and satellite data streams for the period Sept,1957- Aug,2002. There are numerous data products that are separated into dataset series' based on resolution, vertical coordinate reference, and likely research applications. Descriptions of the series organization and direct links to information about all ERA40 products are available.

This dataset contains monthly means of the ERA40 2.5 dergree latitude-longitude gridded surface and single level analysis. Monthly means have been computed for each analysis hour as well as a daily mean.

The ERA-Interim data from ECMWF is an update to the ERA-40 project. The ERA-Interim data starts in 1989 and has a higher horizontal resolution (T255, N128 nominally 0.703125 degrees) than the ERA-40 data (T159, N80 nominally 1.125 degrees). ERA-Interim is based on a more current model than ERA-40 and uses 4-D VAR (as apposed to 3-D VAR in ERA-40). ECMWF will continue to run the ERA-Interim model in near real time thru at least 2010, and possibly longer. This data is available in ds627.0.