Analyzing & Estimating Fluid Flow Properties via the Ergodicity Defect

The ergodicity defect has been used as a method for identifying Lagrangian coherent structures in ocean flows - see ( npg-2011-14). The general idea is that the ergodicity defect distinguishes trajectories in terms of how they sample the flow - i.e., in terms of ergodicity - and this in turn is used to identify coherent structures in the flow. In this presentation, we explore how best to use the ergodicity defect for analyzing fluid flow properties both in terms of obtaining a better estimate of the properties and in terms of understanding the transport of material properties by coherent structures in the flow. For example, we investigate the usefulness of the ergodicity defect for determining an optimal estimate of temperature by weighting Lagrangian drifters via their defect values.