Nanosecond Radar Observations of the Ocean Surface from a Stable Platform

To obtain information on the potential usefulness of a radar altimeter as a remote ocean sensor, an experimental description of the ocean radar reflectivity is needed. This can be derived from an investigation of the electromagnetic impulse response of the sea surface at vertical incidence over a wide range of sea state conditions. For this purpose, Naval Research Laboratory has assembled a 1-ns radar and placed it on the Chesapeake Light Tower where, with a moderate antenna size, high spatial resolution is obtained. By recording the return over several minutes, the radar reflection from different portions of the vertical water wave structure is measured. The average radar returns then present the effective impulse response of the ocean. Simultaneously with the radar measurements, wave staff measurements of the water wave structure are obtained so that the relation between the geometric and electromagnetic surface distribution can be established. Preliminary results are shown without interpretations to show the effectiveness of a nanosecond radar to measure the ocean surface characteristics.