Validation and intercomparison of SSM/I rain-rate retrieval methods over the continental United States

An important source of error or ambiguity in the satellite passive microwave detection and estimation of precipitation rate over land is variable background emission, reflecting differences in surface temperature and moisture, soil type, and vegetation cover. Three experimental algorithms for the Special Sensor Microwave/Imager (SSM/I) are described that attempt to improve the precipitation signal-to-noise ratio by selectively responding to transient brightness temperature perturbations relative to maps of seven-channel monthly mean radiances.