NONLINEAR DYNAMICS OF THE GREAT-SALT-LAKE - SYSTEM-IDENTIFICATION ANDPREDICTION

A case study of the application of recent methods of nonlinear time se ries analysis is presented. The 1848-1992 biweekly time series of the Great Salt Lake (GSL) volume is analyzed for evidence of low dimension al dynamics and predictability. The spectrum of Lyapunov exponents ind icates that the average predictability of the GSL is a few hundred day s. Use of the false nearest neighbor statistic shows that the dynamics of the GSL can be described in time delay coordinates by four dimensi onal vectors with components lagged by about half a year. Local linear maps are used in this embedding of the data and their skill in foreca sting is tested in split sample mode for a variety of GSL conditions: lake average volume, near the beginning of a drought, near the end of a drought, prior to a period of rapid lake rise. Implications for mode ling low frequency components of the hydro-climate system are discusse d.