An evaluation of the ERA-Interim global reanalysis at high latitudes

The European Centre for Medium-Range Weather Forecasts (ECMWF) has produced two global reanalyses: ECMWF 15-year and 40-year reanalyses (ERA-15 and ERA-40). Now the next generation global reanalysis, known as 'ERA-Interim', is underway. ERA-Interim begins in 1989, and is intended to be run in near real-time. The first 17 years, 1989-2005, of the validated ERA-Interim analysis products are currently (last updated December 2008) available on the ECMWF Data Server at 1.5° resolution, including several products that were not available for ERA-40. The ERA-Interim archive is more extensive than that for ERA-40, e.g., the number of pressure levels is increased from ERA-40's 23 to 37 levels and additional cloud parameters are included.

Comparisons between ECMWF-Interim and two current major reanalysis datasets, NCEP/DOE Reanalysis (NCEP-2) and Japanese Reanalysis (JRA), are performed from 1989 to 2005; as well as to its predecessor ERA-40 from 1989 to August 2002. Means and trends of general meteorological variables, as well as each term of the atmospheric moisture budget are examined over the Arctic and Antarctic regions. An initial assessment of quality of ERA-Interim over both polar regions will be presented.