Comments and suggestions of two anonymous reviews improved the presentation of this work. The authors thank Ricardo Todling (NASA DAO) for his comments, suggestions, and corrections. IRI is supported by its sponsors and NOAA Office of Global Programs Grant NA07GP0213. Craig Bishop received support under ONR Project Element 0601153N, Project Number BE-033-0345, and also ONR Grant N00014-00-1-0106.
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