Review Article Remotely-sensed tracers for hydrodynamic surface flow estimation

Abstract

Research results concerning tracers useful for estimating hydrodynamic surface flow are reported. Tracer characteristics analysed include spectral signatures, mapping transformations, sensor penetration depths, conservativeness and horizontal variability. Fluorescent dye is limited in usefulness to small area Lagrangean drift estimates. Suspended sediments and salinity are limited to single-date descriptive and Lagrangean drift estimates for estuarine and adjacent coastal waters. Chlorophyll pigments and surface temperature are the most ubiquitous properties and hold the most potential to be useful tracers. This is particularly the case for coarse- to meso-scale circulation of coastal ocean waters. Potential drawbacks of chlorophyll and surface temperatures as tracers must be overcome prior to their successful application for flow estimations by (1) compensating for non-conservative sources/sinks; (2) achieving imaging precision sufficient to resolve tracer levels at smaller space scale; and (3) acquiring the ability to remove spatially inhomogeneous atmospheric effects.