Lagrangian and Eulerian Indicators in a Velocity Field from the Chesapeake Bay

Abstract: Velocity fields that we normally encounter in nature do not often share the properties of smoothness and completeness that the dynamical systems introduced in textbooks enjoy; this is especially true of dynamical systems that arise in geophysical fluid dynamics, where the fields are known only at discrete values, spatially and temporally. For these incomplete fields the challenge is to define the analogues of invariant manifolds and Liapunov exponents, to mention just two key computational tools from dynamical systems theory. In this talk I will describe how this challenge is being addressed, by introducing the mathematical and computational issues we need to confront in the context of a Chesapeake Bay velocity field.