Gridded analyses produced by ECMWF were obtained from the National Center for Atmospheric Research, which is supported by the National Science Foundation. The outgoing longwave radiation data of Liebmann and Smith (1996) were obtained electronically; we thank Catherine Smith of the University of Colorado for her assistance in this process. Positions of eastern Pacific tropical cyclones were obtained electronically from the National Hurricane Center (NHC). We thank Lixion Avila and Richard Pasch of NHC for providing additional information on eastern Pacific tropical depressions 5 and 10. This work is supported by National Science Foundation Grant ATM-9900671 and Office of Naval Research Grant N00014-98-10599.
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