Improved Rainfall Detection Using High Frequency Observations from the NOAA Advanced Microwave Sounding Unit (AMSU)

Over the past decade, precipitation retrievals from satellite borne passive microwave radiometers have been instrumental to weather forecasters monitoring approaching storms along the west coast of the United States. This is particularly true in situations where the storm is well out of radar range and when the land falling storm contains rain bands for hundreds of miles off-shore. In many instances, the precipitation occurs in surges, the timing of which is not well predicted by forecast models.

The NOAA based Advanced Microwave Sounding Unit (AMSU), initially placed into operation in May 1998 on the NOAA-15 satellite (and subsequently followed by the NOAA-16 in September 2000) offers an improved measure of precipitation systems offshore and over land. In particular, the use of measurements at 89 and 150 GHz are critical for detecting regions of stratiform rain.

This paper will present case studies of the evolution of storm systems along the California coast during the winter of 1999-2000, provide validation using ground radar and rain gauges, and present ongoing improvements to the retrieval algorithm.