The project “Evaluation of Algorithms for Retrieval of Rain Rate with Passive Microwave Radiometers” has been carried out by the University of Bremen for the European Space Agency. Three investigations have been completed under this project:

1. review, implementation, and evaluation of algorithms for rain retrieval over land:
2. analysis of the spatial and temporal sampling problem including beam-fillingeffects for the SSM/I and MIMR instruments, its impact on rainfall retrievaland possible solutions; and
3. review and comparison of image restoration algorithms for resolution improvement.

This Executive Summary presents the results of these investigations in the form of two papers to be published in the ES,4 Journal. The first paper “Rain Retrieval over Land with Passive Microwave Satellite Sensors: Errors due to Surface Variation and Sensor Sampling Characteristics” summarizes the results obtained in the first two investigations.