A Long-range Ocean Radar for Ocean Surface Studies using Backscatter Via the Ionosphere

Abstract

An HF Doppler radar, designed for use at long range via an ionospheric propagation mode, has been developed primarily for the determination of wave states over large ocean areas. The operating frequency is 21 ·840. MHz, and the array is physically rotatable through a full 3600 of azimuth, thus allowing for great flexibility in the choice of target area. The experimental technique utilizes a well-known resonance interaction mechanism for electromagnetic waves backscattered from a moving sea wave surface to derive sea state parameters in the scattering region for input to oceanographic and meteorological synoptic data networks. An ultimate angular resolution of less than 10 of azimuth, coupled with high operational flexibility, suggest possible utilization of the aerial array for tracking and interrogating free-floating ocean buoys, tracking radio noise associated with tropical cyclones and investigating aspects of ionospheric dynamics.