The Significance of the Date of Snow Disappearance on the Arctic Tundra as a Possible Indicator of Climate Change

Variations in the length of the snow-cover season affect the albedo which in turn impacts the energy balance; thus, it is important to have a data set concerned with the spatial and the temporal character of snow. Data on the date when the arctic snow cover disappears in the spring is presented and analyzed for 12 stations between 68 and 74?N latitude. For a few of the stations, data are available for over 50 yr; however, Soviet data are available only from the late 1930s until the mid 1950s, and Canadian data have only been recorded since the late 1950s. Results show that for much of the North American arctic tundra the date of snow disappearance has been occurring earlier in the spring since the late 1960s. For Barrow, Alaska, there has been a trend towards earlier snowmelt since about 1950. It is not yet apparent as to whether this trend can be attributed to increases in carbon dioxide and soot in the arctic environment or whether a particular circulation regime, such as a shift in the location of the polar vortex, may be responsible. But because the Arctic is where anthropogenic atmospheric pollution is expected to have the largest impact on climate, and in view of anticipated increased future emissions of carbon dioxide and soot, a more complete and lengthy snow-cover data set may provide an early indication of the onset of the predicted warming of the polar climate.