The authors would like to acknowledge M. Kimoto for providing the data described in this paper, J. Roden and Y. Tian for assistance in preprocessing the data and graphics, and J. M. Wallace and Springer-Verlag for permission to use a copy of the three height anomaly panels in Fig. 11 of Wallace (1996) as Figs. 8b, d, f here. We benefited from the intellectual input of A. Fraser, I. Jolliffe, M. Kimoto, T. N. Palmer, A. W. Robertson, M. Turmon, R. Vautard, and J. M. Wallace. We are also grateful to A. R. Hansen for his constructive review and to two anonymous reviewers for useful comments. The research described in this paper was carried out in part by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The work of PS was supported in part by NSF Grant IRI-9703120. The work of MG and KI was supported by NSF Grant ATM95-23787 and NASA Grant NAG 5-713.
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