This work was supported by National Science Foundation Grant ATM-0226141 and by National Oceanographic and Atmospheric Administration Grants GC01-229 and GC01- 246. Soon-Il An was supported by Frontier Research System for Global Change through its sponsorship of the International Pacific Research Center. The authors thank Shang-Ping Xie for the valuable comments, and Diane Henderson and May Izumi for the careful reading and editing of the manuscript.
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