Support for the authors during preparation of this manuscript was provided by the National Science Foundation through Grant OCE91-14656. The SOFAR float observations were supported by NSF through Grants OCE85-17375 and OCE85-21082 to W. J. Schmitz and P. L. Richardson. The float trajectories were processed by Marg Zemanovic and Chris Wooding. We thank Ed Ryan and Arthur Mariano for sharing data and figures from their global shipdrift climatology. The comments and suggestions of Larry Pratt and two anonymous reviewers helped focus and improve this manuscript.
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