Modeling Impacts On and Feedbacks Among Surface Energy and Water Budgets Due to Aerosols-In-Snow Across North America

Tuesday, 16 December 2014: 5:00 PM
Catalina M Oaida1, Yongkang Xue1,2, Mian Chin3, Mark Flanner4, Fernando De Sales2 and Thomas H Painter5, (1)University of California Los Angeles, Department of Atmospheric and Oceanic Sciences, Los Angeles, CA, United States, (2)University of California Los Angeles, Department of Geography, Los Angeles, CA, United States, (3)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (4)University of Michigan, Ann Arbor, MI, United States, (5)NASA Jet Propulsion Laboratory, Pasadena, CA, United States
Snow albedo is known to have a significant impact on energy and water budgets by modulating land-atmosphere flux exchanges. In recent decades, anthropogenic activities that cause dust and soot emission and deposition on snow-covered areas have lead to the alteration of snow albedo. Our study aims to investigate and quantitatively assess the impact of aerosols-in-snow on surface energy and water budgets at a local and regional scale using a recently enhanced regional climate model that has physically based snow processes, including aerosols in snow. We employ NCAR’s WRF-ARW model, which we have previously coupled with a land surface model, Simplified Simple Biosphere version 3 (SSiB-3). We improve the original WRF/SSiB-3 framework to include a snow-radiative transfer model, Snow, Ice, and Aerosol Radiative (SNICAR) model, which considers the effects of snow grain size and aerosols-in-snow on snow albedo evolution. Furthermore, the modified WRF/SSiB-3 can now account for the deposition and tracking of aerosols in snow. The model is run for 10 continuous years (2000-2009) over North America under two scenarios: (1) no aerosol deposition in snow, and (2) with GOCART dust, black carbon, and organic carbon surface deposition in snow. By comparing the two cases, we can investigate the impact of aerosols-in-snow. We examine the changes in surface energy balance, such as albedo, surface net solar radiation (radiative forcing), and surface air and skin temperature, and how these might interact with, and lead to, changes in the hydrologic cycle, including SWE, runoff, evapotranspiration and soil moisture. We investigate the mechanisms and feedbacks that might contribute to the changes seen across select regions of North America, which are potentially a result of both local and remote effects.