SATELLITE SENSOR ESTIMATES OF NORTHERN-HEMISPHERE SNOW VOLUME

In the northern hemisphere the mean monthly snow-covered area ranges from about 7 per cent of the land area in summer to over 40 per cent in winter, thus making snow one of the most rapidly varying natural surface features. The mean monthly snow volume ranges from about 1.5x 1016g in summer to about 300 x 1016 g in winter. Currently several algorithms utilizing passive microwave brightness temperatures are available to estimate snow cover and depth. The algorithm presented here uses the difference between the 37 GHz channel and the 18 GHz channel of the Scanning Multichannel Microwave Radiometer (SMMR) instrument on board the Nimbus-7 satellite, to derive estimates of snow volume. Even though satellite sensor snow records are currently too short to allow us to recognize trends, continued monitoring over about the next 10 years should enable us to establish whether incipient or current trends are significant in the context of global climate change. © Taylor & Francis Ltd.