GC33E-1348
Modeling Greenland's Climate Response to the Presence of Biomass Burning Aerosols in the Atmosphere and Snow

Wednesday, 16 December 2015
Poster Hall (Moscone South)
Jamie Lynn Ward1, Mark Flanner1, Michael Howard Bergin2,3, Zoe Courville4, Jack E Dibb5, Chris Polashenski6, Amber Jeanine Soja7 and Brandon M Strellis2, (1)University of Michigan Ann Arbor, Ann Arbor, MI, United States, (2)Georgia Inst Tech, Atlanta, GA, United States, (3)Duke University, Durham, NC, United States, (4)CRREL, Hanover, NH, United States, (5)University of New Hampshire Main Campus, Durham, NH, United States, (6)US Army Corps of Engineers, Fort Wainwright, AK, United States, (7)NASA Langley Research Center, Hampton, VA, United States
Abstract:
Biomass burning events are known to produce large emissions of aerosol particles, including light-absorbing black carbon (BC) and brown carbon. Once exported from fire-based source regions to the Arctic via atmospheric transport mechanisms, these particles can change the regional climate through solar absorption while suspended at various heights in the atmosphere or once deposited onto the terrain (through the reduction of surface albedo). Greenland is particularly vulnerable to positive aerosol forcing due to its perennial ice cover and high surface albedo. Surface measurements and remote sensing observations indicate that Greenland is occasionally impacted by smoke from North American and Eurasian wildfires, including during the summer of 2011 when aerosol optical depth (AOD) over central Greenland exceeded 0.20 and aerosol single scattering albedo (SSA) dropped below 0.90. Measurements of impurities in snow pits also indicate that wildfires exerted transient influence on surface albedo during the summers of 2012 and 2013, with average peak BC concentrations of 4 and 15 ng/g, respectively.

Here, we apply idealized climate simulations to study how Greenland surface temperature and melt are affected by elevated levels of light-absorbing particles above and on the ice sheet. We apply the Community Earth System Model (CESM) in a configuration with prescribed sea surface temperatures and active atmosphere and land model components. In one set of experiments, we prescribe constant values of AOD and SSA in the troposphere over Greenland, informed by measurements from 2011. In a second set of experiments we prescribe constant mass mixing ratios of BC and dust in surface snow based on measurements of snow that fell during 2012-2014. These simulations will inform on the amount of excess snow melt that may occur on Greenland due to biomass burning, and on the relative impacts of atmospheric and snow-deposited smoke.

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