DATA ASSIMILATION IN EARTH'S OBSERVATION

The development and elaboration of Earth system models into which data from various sources will be integrated is an important step to ultimately improve our understanding of the Earth's environment. This poses many challenges including those of data validation and assimilation. The former is essential if models are to be trusted and used for prediction of human influences, and the latter if optimal use is to be made of the various sources of data likely to be available.

Data assimilation has already been demonstrated in the field of operational meteorology and the recent advances in oceanic observation from space, in particular altimetric data and are encouraging the development of "ocean forecasting" models of a nature similar to those used by the meteorologists. Data assimilation is now considered as an integral part of any space experiment as demonstrated by its application to stratospheric and tropospheric chemistry and to observation of soil moisture. It also constitutes an appropriate tool for combining space data with ground-based observation and thus for validating both space observation and integrated models.

This presentation will focus on the current state of Earth Observation from space and the role of data assimilation in furthering the field of Earth System Studies.