In support of the COAPEC Thematic Programme the BADC has extracted seasonal forecast ensemble data from the ECMWF MARS (Meteorological Archive and Retrieval System) archive. These data are also known as "Hindcasts" as they are forecasts run retrospectively. Since the data is part of the ECMWF Operational system BADC users must successfully apply for access to this dataset before they can obtain the data.

The ECMWF produced two sets of runs, System 1 and System 2. The data archived at the BADC are the System 2 runs which use the atmospheric component Cy23r4 of the IFS (Integrated Forecasting System) with a horizontal resolution of TL95 at 40 levels in the vertical. This is the same cycle of the IFS used for the ERA-40 re-analysis.

A detailed description of the ECMWF Seasonal Forecasting system can be found on the ECMWF web site.

Products:

The BADC has extracted monthly means, maxima, minima and standard deviations for the available surface variables from 1987 to 6 months before the present date. Atmospheric variables are only currently available as monthly means. The data is held as part of the main BADC Operational ECMWF archive.

For each month there are six forecast months archived, with 5 ensemble members for 10 months of the year, and 40 ensemble members in May and November of each year from 1987-2001. From 2002 onwards there are 40 ensemble members per month. There are 33 parameters held on surface or single levels and 6 parameters available on pressure levels.

The data is held on a regular 1.875 x 1.875 degree grid in GRIB format.