High-resolution topographic imaging of the moving ocean surface

Imaging Doppler radar deployed in an interferometric mode can be used to map the time-varying surface displacement field. Applying techniques common in cross-track SAR interferometry, the authors have used a newly constructed focused phased-array radar to measure backscattered power, Doppler velocity, and surface displacement simultaneously from extended areas of the sea surface. "Direct" imaging of surface displacement via interferometry avoids the need for a surface wave model (linear or otherwise) to retrieve wave heights. They report results of held comparison between radar and wave-wire measurements of surface displacement performed from a small pier. Images of a 20 m/spl times/20 m area resolved to 0.5 m spatial resolution and 0.25 s time resolution were produced. Radar-derived height statistics are well correlated with those obtained by direct measurement. The technique can be extended to larger areas by increasing the height of the radar.