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Support for this study was provided by the National Aeronautics and Space Administration under contract number NNX08AB07G, the National Oceanic and Atmospheric Administration under contract number NA11OAR4600211, and the National Science Foundation under contract number ATM-0809051. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.

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