| The utility of microwave remote-sensing of the ocean surface for current detection is well established. However, the advent of along-track interferometric synthetic aperture radar has provided a new, potentially powerful technique for current mapping. Although interferometric velocity measurements can be used to derive surface currents, the relationship between these two quantities is not always clearly defined. In response, this thesis presents comparisons between interferometric data collected by an X-band phased-array radar and in situ data, thereby demonstrating the relationship of interferometric velocity measurements to surface and subsurface currents. To develop a precise method of estimating the surface current from the interferometric measurements, the wave-orbital velocities and Bragg phase-speed are characterized.; This analysis is extended to compare surface and subsurface water currents. Case studies are presented under varying environmental conditions for which the vertical current structure alters considerably. In these examples, analysis of the radar imagery yields both interferometric surface currents and subsurface current estimates derived from long-wave dispersion characteristics. A vertical profile of current in the water column is generated from the radar-derived velocities combined with coincident Acoustic Doppler Current Profiler measurements, revealing the sensitivity of X-band interferometric measurements to wind-drift and the near-surface current structure. |
