We greatly appreciate the many discussions and help offered by M. Kanamitsu, H. Juang, M. Iredell, S. Saha, J. Purser, J. Derber, S. Tracton, J. Irwin, and P. Caplan at different stages of this work. Jim Purser kindly provided us with the spherical filter used in sections 5 and 6 while Steve Tracton suggested the use of the schematic in Fig. 12. The fact that the breeding method has a strong connection to the Lyapunov vectors was first pointed out to us by Jon Ahlquist and Anna Trevisan. Joe Gerrity, Peter Houtekamer, Tim Palmer, Istvan Szunyogh, and Steve Tracton offered valuable comments on earlier versions of this manuscript.
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