The Indirect and Semi-Direct Aerosol Campaign (ISDAC): Examining the Influences of Arctic Aerosols on Clouds

Greg M. McFarquhar, Univ. of Illinois, Urbana, IL; and S. Ghan, J. Verlinde, A. Korolev, J. W. Strapp, B. Schmid, J. Tomlinson, S. D. Brooks, D. R. Collins, D. Cziczo, M. K. Dubey, I. Gultepe, G. Kok, A. Laskin, P. Lawson, P. Liu, D. Lubin, C. Mazzoleni, A. M. MacDonald, M. Wolde, A. Zelenyuk, R. A. Ferrare, C. Flynn, M. Shupe, D. D. Turner, M. Ovtchinnikov, S. Xie, and X. Liu

Aerosols influence clouds through a variety of mechanisms. Nowhere is this influence more complex than in the Arctic. The Indirect and Semi-Direct Aerosol Campaign (ISDAC), sponsored by the Department of Energy Atmospheric Radiation Measurement (ARM) program, was conducted over Barrow in April 2008 to directly address this complexity. The National Research Council (NRC) of Canada Convair-580 flew a total of 27 sorties during ISDAC, collecting data from 42 cloud and aerosol instruments for more than 100 hours on 12 different days. Several additional instruments were operated at the North Slope of Alaska Barrow facility throughout the campaign. This unprecedented set of in-situ and remote sensing measurements sampled a wide range of aerosol conditions during ISDAC. Data obtained above, below and within single-layer stratus during two golden cases on April 8 and April 26 2008 are allowing for a process-oriented understanding of how cloud-aerosol interactions affects the microphysical and radiative properties of arctic clouds in different surface and aerosol conditions. Data acquired on a heavily polluted day on April 19 are also being used to enhance this understanding.