Applications of Satellite Microwave Radiometry in Finland

Data from the Scanning Multichannel Microwave Radiometer (SMMR) onboard Nimbus-7 satellite were applied to (a) retrieval of the water equivalent of snow cover, (b) discrimination of forest and surface types, and (c) determination of the near-surface wind speed. Several water equivalent retrieval algorithms were tested by using a four-year SMMR data set. The brightness temperature difference between 18 GHz and 37 GHz, vertical polarization, was observed to give the highest correlation coefficient with the manually measured snow water equivalent. The use of satellite microwave radiometer data for forest and surface type discrimination is believed to be the first effort in this field. The 10.7 GHz horizontally polarized SMMR channel was found to yield the near-surface wind speed in the Baltic Sea (width about 200 km) with reasonably good accuracy. Previously developed wind speed algorithms have been applied for areas far away from land.