This IMA Volume in Mathematics and its Applications NONLINEAR PHENOMENA IN ATMOSPHERIC AND OCEANIC SCIENCES is based on the proceedings of a workshop which was an integral part of the 1989-90 IMA program on "Dynamical Systems and their Applications." The aim of this workshop was to promote cross-fertilization of ideas between investigators who are using nonlinear dynamical systems and numerical simulations to study the earth's atmosphere and oceans. We thank George F. Carnevale, Shui-Nee Chow, Martin Golubitsky, Richard McGehee, Raymond Pierrehumbert and George R. Sell for organizing the...