Abstract DUACS is a 3-year project of the European Union Environment and Climate Programme and Centre for Earth Observation (CEO) Programme. Its objective is to develop use of satellite altimetry in the field of climate modelling and forecasting. The DUACS team includes an altimeter data provider (CLS) and four climate groups from ECMWF, CERFACS, the UK Met Office and the Max Planck Institut fur Meteorologie. DUACS aims at demonstrating that altimetric measurements can help climate specialists to improve their models and resulting forecasts. Improved climatic modelling is crucial to provide the political authorities with information about likely climatic changes and the ways to mitigate them. Seasonal forecasting has more immediate applications such as helping in the management of water resources, agriculture and energy production. In the framework of DUACS, the basic altimeter data from the TOPEX-POSEIDON, ERS I and ERS2 missions are further processed to obtain products that can be directly assimilated in coupled ocean-atmosphere models used for climate simulations and climate forecasting. The DUACS products include: u • Along-track, fully corrected, sea surface heights (CORSSH) • Along-track sea level anomalies (SLA) • Gridded maps of the sea level anomalies (MSLA)