This research has benefited greatly from conversations with Anantha Aiyyer, Paul Roundy, and Adam Sobel. We also thank the three anonymous reviewers whose insightful comments significantly improved this paper. We obtained the TMPA data from the NASA Goddard Distributed Active Archive Center (online at http://disc.sci.gsfc.nasa.gov/data/datapool/TRMM/). We are grateful to Dave Vollaro for his assistance in obtaining and interpolating this data. This work was supported by NSF Grant ATM0839991 and NASA Precipitation Measuring Mission Grant NNX07AD45G.
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