02/14/2011
Comprehensive Dataset Helps Scientists Understand Aerosol Impacts on Arctic Clouds
Summary
The Arctic is warming twice as fast as the rest of the Earth. Arctic clouds and aerosols play important roles in controlling the Arctic energy balance, loss of sea ice, and the severity of arctic climate change, yet there is little understanding why Arctic clouds persist as long as they do. DOE researchers from Pacific Northwest National Laboratory collected new cloud and aerosol data during a 12-day period in April 2010, along aerial transects from Barrow to Fairbanks and along the North Slope. The measurements were based on newly designed ice probes with a greater capability to resolve aerosol type with greater precision and spatial variability than was available in earlier field campaigns. Initial results demonstrate a surprisingly strong seasonal difference in the number of ice-forming particles in Arctic clouds compared to results from a similarly conducted campaign in October 2010. Furthermore, while aerosol composition—including fresh and processed sea salt, biomass burning particles, organics, and sulfates mixed with organics—varied markedly between collection flights, there was little observed variation between flights in the type of particles that serve as cloud condensation nuclei. In addition, the number concentration of cloud ice crystals was significantly lower than in previous field campaigns that used less sophisticated sampling technology. The chemical kinetics and aerosol transformation rates in Arctic regions have historically been based, in part, on field observations. These new datasets will require the Arctic scientific community to revisit the chemical controls over aerosol-cloud evolutionary dynamics that in turn govern Arctic atmospheric energy budgets. This study will have a profound influence on the scientific priorities carried out by the Arctic research community.
References
McFarquhar, G., S. J. Ghan, J. Verlinde, A. Korolev, W. Strapp, B. Schmid, J. M. Tomlinson, M. Wolde, S. D. Brooks, D. R. Collins, D. J. Cziczo, M. K. Dubey, J. Fan, C. J. Flynn, I. Gultepe, J. M. Hubbe, M. K. Gilles, A. Laskin, P. Lawson, W. R. Leaitch, P. Liu, X. Liu, D. Lubin, C. Mazzoleni, A. M. Macdonald, R. C. Moffet, H. Morrison, M. Ovchinnikov, D. M. Ronfeld, M. D. Shupe, D. D. Turner, S. Xie, A. Zelenyuk, K. Bae, M. Freer, and A. Glen. 2010. “Indirect and Semi-Direct Aerosol Campaign (ISDAC): The Impact of Arctic Aerosols on Clouds,” Bulletin of the American Meteorological Society, 92, 183–201. DOI: 10.1175/2010BAMS2935.1.