TIGGE, the THORPEX Interactive Grand Global Ensemble, is a key component of THORPEX: a World Weather Research Programme to accelerate the improvements in the accuracy of 1-day to 2 week high-impact weather forecasts for the benefit of humanity. The basic components of TIGGE will be global ensembles run to around 14 days, including those run currently at a number of operational centres (Australia, Brazil, Canada, China, Japan, Korea, UK, USA and ECMWF). These will be collected in near real time from and stored in a common format in three Archive Centres (NCAR, CMA - the Chinese Meteorological Administration and ECMWF) for access by researchers in operational centres and the academic communities.

This project poses important technical challenges, ranging from the agreement on a common data format, the definition of an homogeneous catalogue of products, the daily collection of about 200GB of data over the Internet from various parts of the the world and the implementation of efficient data retrieval facilities.