Airborne Remote Sensing of Inner Shelf Sub-mesoscale Processes

Remote sensing observations from a pilot experiment were made of the inner-shelf and coastline near Point Sal California, using airborne sensors that include a dual-beam along-track interferometric synthetic-aperture radar (ATI-SAR), and thermal infrared (IR) and visible-band cameras. Our goal was to observe and characterize the surface signature and spatio-temporal development of coastal flow features, in areas strongly affected by local changes in bathymetry and variable stratification. Synoptic thermal maps show highly three-dimensional internal wave-like structures, sharp fronts, rip current plumes, and turbulent surface flow around the Point Sal headland. Surface velocity fields show the structure of the flow around the point and at frontal features. We will present our observations and analysis, showing that inner shelf circulation and frontogenesis is an amalgam of processes including up- and down-welling resulting from variable winds, complex flows and around the many headlands, internal wave bores that become unstable and "break", and surface wave breaking at the shore. Our observations were made in collaboration with modeling efforts and in situ measurements (ship, mooring, and drifter observations) to characterize and predict the 3D evolution of inner shelf features and their contribution to inner shelf dynamics.