The San Clemente Ocean Probing Experiment: a study of air-sea interactions with remote and in situ sensors

A multifaceted experiment was performed in September 1993 by the NOAA Environmental Technology Laboratory (ETL) near San Clemente Island, 100 km offshore of San Diego, to investigate environmental effects on microwave scattering and emission from the sea surface. The experiment, called the San Clemente Ocean Probing Experiment (SCOPE), employed simultaneous measurements of X-band radar cross section and of atmospheric parameters that govern the radar scattering cross section such as atmospheric surface-layer stability, wind, and friction velocity. These measurements were made simultaneously with surface wave measurements from the Scripps Institute Floating Instrument Platform (FLIP), measurements from an airborne microwave radiometer, and images from airborne and satellite-borne synthetic aperture radars. Preliminary results indicated the following: (1) surface currents are potentially measurable to a precision of a few centimeters per second with the Δ-k radar technique; (2) disturbances on the marine inversion may occasionally cause strong modulations of radar images of the ocean at low grazing angles; (3) horizontal polarization was much more effective than vertical at depicting ship wakes; and (4) an atmospheric boundary layer (ABL) eddy forms in the lee of the island as observed by the ETL Doppler lidar; surface manifestations of the eddy are apparent in the island-based X-band radar and in synthetic aperture radar (SAR) images of the ocean surface. First looks at data from the newly developed array of pressure transducers revealed interesting transitions of the wave field, wave packet signatures, and standing wave patterns