Estimating soil moisture from satellite microwave observations: Past and ongoing projects, and relevance to GCIP

On the basis of a series of studies conducted in Botswana and preliminary r esults from an ongoing study in Spain, developments in microwave remote sen sing by satellite, which can be used to monitor near-real-time surface mois ture and also study long-term soil moisture climatology, are described. A p rogression of methodologies beginning with single-polarization studies and leading to both dual polarization and multiple frequency techniques are des cribed. Continuing analysis of a 9 year data set of satellite-derived surfa ce moisture in Spain is ongoing. Preliminary results from this study appear to provide some evidence of long-term desertification in certain parts of this region. The methodologies developed during these investigations can be applied easily to other regions such as the GCIP area and could provide us eful databases for simulation and validation studies. Additionally, they ha ve strong potential for global applications such as climate change studies.