Spring snow melt timing and changes over Arctic lands

Abstract

Spring snow cover over Arctic lands has, on average, melted approximately 4–7 days earlier since the late 1980s compared to the previous 20 years. The earlier disappearance of snow has been identified in non-mountainous regions at the 60° and 70°N parallels over Eurasia and North America using visible satellite observations of continental snow cover extent (SCE) mapped by the National Oceanic and Atmospheric Administration (NOAA). The change was greater in the farthest north continental locations. Northern Hemisphere SCE declined by almost 10% (May) to 20% (June) between the two intervals. At latitude 70°N, eight segments of longitude (each 10° in width) show significant (negative) trends. However, only two longitudinal segments at 60°N show significant trends, one positive and one negative. SCE changes coincide with increasing spring warmth and the earlier diminution of sea ice in the last several decades. However, while sea ice has continued to decrease during this recent interval, snowmelt dates in the Arctic changed in a step-like fashion during the mid to late 1980s and have remained much the same since that time.

Acknowledgements

This work is supported by NOAA grants EA133E05SE6044 and NA040AR4310170 to Rutgers. Thanks to Dr. Judah Cohen and to the reviewers for their suggestions.