Satellite-based high latitude snow volume trend, variability and contribution to sea level over 1989/2006

Abstract

Snow volume change over the 1989/2006 period has been derived from Special Sensor Microwave/Imager (SSM/I) radiometric measurements for all land surfaces above 50°N, except Greenland. The mean annual snow volumes over the whole study domain, Eurasia and North America are respectively equal to 3713 km 3, 2272 km 3 and 1441 km 3, for the Pan Arctic regions, over this 18-year time period. While the snow volume exhibits a statistically significant negative trend (−9.7 ± 3.8 km 3 yr −1, p-value = 0.02) over North America, it presents a positive, but not statistically significant trend (11.3 ± 9.3 km 3 yr −1, p-value = 0.25) over Eurasia. These opposite variations can be related to different regional climatic conditions over these two regions: over Eurasia, snow depth is mainly influenced by the Arctic Oscillation (AO) and the Atlantic Multidecadal Oscillation (AMO)-correlation coefficient = 0.68 between the SSM/I-derived snow volume and a linear combination of AO and AMO indices, whereas over North America snow depth is mainly influenced by the Pacific North American (PNA) pattern and the AMO-correlation coefficient = 0.75 for a linear combination of the PNA and AMO indices. This study confirms that snow volume is a key driver of the sea level seasonal cycle, but net snow volume trend for the Pan Arctic regions indicates a negligible and not statistically significant contribution to sea level rise (−0.004 ± 0.009 mm yr −1, p-value = 0.88 once converted into sea level).