The Development of SSM/I Rain-Rate Retrieval Algorithms Using Ground-Based Radar Measurements

Abstract

Rainfall algorithms developed for the DMSP Special Sensor Microwave/Imager are presented and then ?calibrated? against ground-based radar measurements to develop instantaneous rain-rate retrieval algorithms. These include both scattering- and emission-based algorithms. Radar data from Japan, the United States, and the United Kingdom have been used in the investigation. Because of the difficulties in accurately matching the satellite and radar measurements in both time and space, an approach where both measurements are grouped in 1 mm h?1 rain-rate bins provides a much more accurate set of measurements to be used in the derivation of coefficients for instantaneous rain-rate retrieval. Both linear and nonlinear relationships are developed, with the nonlinear fits being more accurate and supported by model simulations. An application of the derived instantaneous rain-rate relationships to an independent case is presented, with approximately a 10% error for the scattering algorithm when compared with radar-derived rain rates.