Here we report on an effort to describe in detail the evolution of surface water particles in Monterey Bay from the time they first enter until the time they leave. The data used for this study are objective mappings from hourly surface currents obtained from high frequency (HF) radar measurements in Monterey Bay for the period 2 June through 4 August 1999. The basic concept is simple: compute the origin and fate of a large number of particles for every hour during the analysis period. However, analyzing and displaying the enormous amount of computed trajectory information required a new data compression technique: synoptic Lagrangian maps produced by representing each trajectory by its origin/fate and its residence time. The results show unexpected complexity and variability not apparent in the Eulerian current archive. For example, the fraction of particles that escaped to the open ocean during this period varied from about 17 to more than 92 percent. Mean particle residence times ranged from 4.5 to 11 days. The distribution of particle residence times and transport pathways varied over time scales from hours to weeks, and space scales from 2 to 40 km. The wide range of variability in particle properties reported here shows that surface transport studies in Monterey Bay require detailed wind and tidal current information over the entire bay, as well as information about the flow along the open ocean boundary.

In the past five years there have been si@cant advances in dynamical systems theory to the point where the framework can now be utilized in the context of "real" problems. In this talk we will briefly describe the dynamical systems framework for Lagrangian transport and the new analysis tools it gives us for obtaining synoptic summaries of particle motion. Our focus will be on transport in a coastal system (i.e., Monterey Bay) using a velocity field obtained from high frequency (I-E) radar measurements.In this talk we describe two new analyt~cal techniques for studying transport: synoptic Lagrangian maps (SLMs) and incoming/exiting regions. SLM's is a method for compressing the information contained in millions of trajectories and, at the same time, reveals detailed, timedependent, L a p g i a n structures. The incominglexiting regions reveal the time varying, geometrical structures in the flow responsible for controlling access to the bay. Both methods also provide novel ways to compute certain statistical quantities related to transport. 0-933957-30-0 2044