We thank the NOAA/CDC for making the NCEP–NCAR reanalysis data available. The ARSC supplied some computer resources. We thank M. Timlin for evaluating the temporal distribution of the most extreme events. We also thank Drs. S. Akasofu and R. Gerdes for their valuable comments. Finally, we are grateful to the editor, M. P. Hoerling, and two anonymous reviewers, whose careful and constructive reviews improved both presentation and content of this paper. Authors X. Zhang, U. S. Bhatt, and M. Ikeda were supported by the Japanese Marine Science and Technology Center through the International Arctic Research Center, University of Alaska, Fairbanks. J. E. Walsh was funded by the National Science Foundation through Grant OPP-0002239. J. Zhang was supported by funding from the University Partnership for Operational Support.
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