The use of passive microwave imagery in rainfall monitoring

This paper reviews progress made in rainfall estimation by satellite methods over the last two decades. The potential role of passive microwave imagery from satellites is discussed, the instrumental systems used to make microwave observations from space are described, and the limitations of the data provided by them are reviewed. The basic principles which govern rainfall assessment using passive microwave observations are examined, and the fundamental differences between the operation of these principles over land and sea are summarised. Finally, there is discussion of the present possibilities for the monitoring of rainfall simultaneously over both land and oceans.