Indirect and Semi-Direct Aerosol Campaign (ISDAC): the Influence of Arctic Aerosol on Clouds

Greg McFarquhar University of Illinois, Urbana
Steven Ghan Pacific Northwest National Laboratory
Johannes Verlinde Pennsylvania State University
Beat Schmid Pacific Northwest National Laboratory
Jason Tomlinson Pacific Northwest National Laboratory
John Hubbe Pacific Northwest National Laboratory
Debbie Ronfeld Pacific Northwest National Laboratory
Sarah Brooks Texas A&M University
Don Collins Texas A&M University
Daniel Cziczo Massachusetts Institute of Technology
Manvendra Dubey Los Alamos National Laboratory
Mary Gilles Lawrence Berkeley National Laboratory
Ismail Gultepe Environment Canada
Greg Kok Droplet Measurement Technologies
Alexei Korolev Environment Canada
Alexander Laskin Pacific Northwest National Laboratory
Paul Lawson SPEC, Inc.
Peter Liu Environment Canada
Claudio Mazzoleni Michigan Technological University
Ann Marie Macdonald Environment Canada
Ryan Moffet University of the Pacific
J. Walter Strapp Environment Canada
Alla Zelenyuk-Imre Pacific Northwest National Laboratory
Connor Flynn Pacific Northwest National Laboratory
Dan Lubin National Science Foundation
Richard Ferrare NASA - Langley Research Center
Matthew Shupe University of Colorado
David Turner National Oceanic and Atmospheric Administration
Mengistu Wolde National Research Council
Mikhail Ovchinnikov Pacific Northwest National Laboratory
Shaocheng Xie Lawrence Livermore National Laboratory
Xiaohong Liu University of Wyoming

Category: Field Campaigns

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) 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 cloud, aerosol, and remote sensing instruments 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 affect the microphysical and radiative properties of arctic clouds in the different surface and aerosol conditions. Samples acquired during a heavily polluted day on April 19 also are being used for this understanding. The ISDAC data are currently being used to address the following primary science questions: 1. How do the properties of arctic aerosol during April differ from those measured by the Mixed-Phase Arctic Cloud Experiment (M-PACE) during October 2004? 2. To what extent do different properties of arctic aerosol during April produce differences in microphysical and macrophysical properties of clouds and the surface energy balance? 3. How well can cloud models and parameterizations in large-scale models simulate the sensitivity of arctic clouds and the surface energy budget to the differences in aerosol properties? 4. How well can long-term surface-based measurements at the ACRF Barrow site provide retrievals of aerosols, clouds, precipitation and radiative heating in the Arctic? The ISDAC data are also being used to determine the extent to which shattering of large crystals on protruding edges of probes can artificially amplify the measured concentrations of ice crystals with maximum dimensions < 50 micrometers and to examine the composition of ice nuclei.

This poster will be displayed at ARM Science Team Meeting.

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