228 The Impact of Declining Sea Ice on Arctic Precipitation and Snowfall in Autumn

Monday, 23 January 2017
Alexander Carne, University of Nebraska, Lincoln, NE; and M. R. Anderson

Anthropogenic global warming is leading to dramatic changes in Earth’s climate system.  These changes are amplified in the Earth’s cryosphere, where the loss of glaciers and sea ice add a positive feedback on climate change.  One notable impact of global warming has been a loss of summer sea ice across the Arctic Ocean basin.  September 2012 witnessed a record low Arctic sea ice minimum, and future projections lead to a near total loss of summer Arctic sea ice as early as the 2030’s.  The increase in open water across the Arctic Ocean is leading to higher moisture and heat fluxes into the atmosphere above, altering the boundary layer profile over the region of sea ice decline.  This study questions the impact of sea ice decline on Arctic precipitation and snowfall over the September-December time period.  Autumn is the timeframe of interest as the Arctic environment currently remains cold enough to support autumn snowfall, even with the impacts of climate change. With a greater availability of moisture in the Arctic atmosphere, it is hypothesized that autumn precipitation and thus snowfall will increase across high latitude continents, especially in locations along the Arctic coast.     

A reanalysis study was conducted using the WRF model, producing data from September 1st through December 31stfor the years 1982, 1985, 2007, and 2012.  A 36km-12km nested domain was used to run the Era-Interim reanalysis data across the arctic region.  Results provide monthly precipitation and snowfall totals for each year.  Additionally, case studies are conducted where similar synoptic weather patterns are run over differing sea ice conditions, determining the impact of sea ice decline on precipitation and snowfall within individual cyclones. 

The results of this study will go a long way toward understanding the feedback effects of a reduced Arctic sea ice extent.  Snow cover in the Arctic has a significant impact on temperatures, and any change in snowpack onset or depth can alter the regional transition into the cold season.  Additionally, changes in precipitation will impact the hydrologic cycle of the typically dry arctic region.  Local impacts will have the potential to feedback on large scale synoptic weather patterns, leading to remote impacts as well.  There is still much to learn about the effects of declining Arctic summer sea ice, and continued research will advance the understanding of the impact of climate change on the fragile Arctic environment. 

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