Earth and Atmospheric Sciences, Department of


Date of this Version



Geophysical Research Letters, Vol.17, No. 10, pp. 1557-1560, September 1990.


Copyright 1990 by the American Geophysical Union. Used by permission.


Northern hemisphere snow cover during 1988 and 1989 was at its lowest extent since the advent of reliable satellite snow-cover monitoring 1972; running some 8-10% below the eighteen-year annual mean of 25.7 million km2 . Monthly minima for the period of record occurred six times during these two years. In general, the last nine years of the satellite record had less extensive cover than the 1972-80 interval. Negative anomalies during the 1980s were largest over Eurasia in all seasons, and in the Spring over North America. Hemispheric seasonal means for the most recent nine years were 3.7% to 8.4% lower then those between 1972 and 1980. Results are based on analysis of National Oceanic and Atmospheric Administrations weekly snow charts, which are produced from visible satellite imagery.