Capabilities and Limitations of Estimating Cloud Amount from the Special Sensor Microwave/Imager (SSM/I)

摘要

A new operational sensor will be on board the next polar-orbiting defense Meteorological Satellite Program spacecraft, which is scheduled to be launched in June 1987. It is called the Special Sensor Microwave/Imager (SSM/I). The SSM/I is a seven channel, four frequency linearly polarized, passive microwave radiometer. The SSM/I will provide estimates of several surface and atmospheric parameters. One of the parameters is cloud amount (percent cloud coverage), which is the topic of this report. SSM/I cloud amount estimates will include some of the situations in which there are difficulties with the Air Force Global Weather Central's Real-Time Nephanalysis automated global cloud analysis using visible and infrared satellite data. Hughes Aircraft Company developed two algorithms for estimating cloud amounts from SSM/I brightness temperatures. One is applicable over snow backgrounds; the other, over land backgrounds. However, it is not possible to obtain cloud amount estimates for land covered with vegetation. No cloud amount estimation algorithms for ocean or oceanic ice backgrounds were required to be developed; even though the potential over both of these backgrounds is good. (RH)