Coastal Ocean Dynamics Applications Radar - Applications

Applications

Measuring surface currents is the primary result obtained by using CODAR. Ranges achieved and resolution vary with environmental conditions and antenna placement. In general, however, in their long-range mode, modern CODAR can measure out to 100–200 km offshore with a resolution of 3–12 km. By increasing the frequency, resolutions as fine as 200–500 m can be obtained, but the observation range is shortened (15–20 km).

However, the actual range can be limited by radio interferences, high-ocean states and ground conditions in the vicinity of the antennas. Wet and moist sandy soils enhance the ground wave propagation, whereas dry and rocky grounds reduce signal strengths.

A single CODAR system can measure only the component of surface current travelling toward or away from the radar so, to determinate the total surface current vectors, it is necessary to use at least a two-systems set up. A series of CODAR sites can be employed to obtain regional coverage. In a multiple radar configuration, spacing between two radar systems should be approximately 15 to 40 km for long-range open ocean mode and 8 to 20 km for “higher frequency, higher resolution, shorter range” mode.

Typically, CODAR data are averaged over one hour to reduce the noisiness of the sea echo. Therefore, current maps can be produced every hour. This period can be reduced to approximately 20 minutes, however the data may become noisy over such a short period.

CODAR’s measurements are interesting for both military and civil purposes. Main applications are for example coastal engineering and public safety projects, planning of navigational seaways, mitigation of ocean pollution, search and rescue operations, oil-spill mitigation in real time and larval population connectivity assessment. Also, data obtained by using CODAR are used as inputs for global resource monitoring and weather forecasting models and are particularly helpful for tidal and storm-surge measurements. Moreover, from the measurements can be extracted the direction of propagation of wave energy and the period of the most energetic waves, which are important data for many practical applications in design and operation of coastal and offshore structures.