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This study was supported by the National Oceanic and Atmospheric Administration under contract DG133R-08-CO-0062 Task Order #12, the National Aeronautics and Space Administration under contract NNX08AB07G, the National Science Foundation under Grant No. ATM-0809051, the Department of Energy under contract DE-SC0005113, and the U.S. intelligence community. Any opinions, findings, and conclusions, or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the sponsoring agency or any of its subagencies.
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