Trends and variability of snowfall and snow cover across North America and Eurasia. Part 2: What the data say

Snow is a significant factor in the national economy and water resources of Northern Hemisphere countries. Snow also has an important role in climatology, both reflecting climatic changes and fluctuations as well as exerting an influence on climate. The advent of satellite monitoring of weather and climate variables enabled scientists to develop and analyze hemispheric snow cover extent using a consistent database. Unfortunately, the satellite snow record goes back only some four decades. In situ observations of snow cover as well as snowfall are available for some stations going back to the beginning of the Twentieth Century. The in situ data have been analyzed by several researchers, but these analyses have largely been done independently on regional to national scales.

The research presented in this paper and a companion contribution (cf. Heim and Robinson) includes a comprehensive analysis of in situ snow observations from stations in the United States, Canada, and the Former Soviet Union using a consistent methodology applied to all of the stations. This paper discusses the second portion of the effort, and includes, 1) how the station snow indices were combined into national, continental, and hemispheric aggregates, 2) a summarization of the trends and variability of these aggregate indices over the Twentieth Century, and 3) a comparison of these results to other measures of snow variability derived from national in situ analyses and the hemispheric satellite snow cover record.