HF Radar Observations of Oceanic and Atmospheric Dynamics

Abstract : The long-term goal of this research is to develop multifrequency, high-frequency (HF) radar techniques and instrumentation for measuring surface currents, waves, and winds in coastal regions and large lakes for scientific, civil, and military applications. The goals include deployment of HF radar systems in coastal regions for air-sea interaction and coastal oceanography research as well as technology development. This project began with the completion and deployment of two multifrequency HF radar instruments (called MCR for Multifrequency Coastal Radar) to Monterey Bay, California. The radars were then transported to sites near the mouth of Chesapeake Bay to participate in the Chesapeake Bay Outflow Plume Experiment (COPE-3) experiment. These units were operated on four frequencies to gather information on currents at depths of from 0.3 to 1.5 m below the surface. The two units were situated so as to have overlapping coverage and thus produce current vectors from the radial currents measured at each site. Regarding azimuthal resolution, data from all sites was processed with both beam forming and direction finding (MUSIC) methods to assess the effectiveness of these two techniques. In addition, a simulation effort was begun to investigate the accuracy of these techniques, particularly the relative effectiveness of the beam forming and direction finding (MUSIC) methods for obtaining azimuthal resolution. To study air-sea interactions we compared HF radar current measurements with environmental observations, primarily surface current and current shear with wind. To obtain information regarding HF techniques, data from three independent radar systems were collected during the COPE-3 experiment and HF measurements of surface currents were compared with acoustic doppler current profiler (ADCP) data.