OBSERVED IMPACT OF SNOW COVER ON THE HEAT-BALANCE AND THE RISE OF CONTINENTAL SPRING TEMPERATURES

Analysis of satellite-derived snow cover, radiative balance, and surfa ce air temperature over Northern Hemisphere extratropical land shows t hat the retreat of the Northern Hemisphere's extent of spring snow cov er over the past 20 years parallels a change in the influence of snow cover on the radiative balance and an observed increase of spring temp eratures over the same area. These results help explain why the long-t erm (20th century) increase in surface air temperature over Northern H emisphere land has been greater in spring than in any other season rel ative to the interannual variability.