L. I. Dzvonkovsky, V. A. Sobchuk, A. L. Dzvonkovskaya
The development and application of modern coastal oceanographic high-frequency (HF) radar are considered for research and practical use to provide economical activities in the Economic Exclusive Zone.
The existing contact methods of sea surface measurements, e.g. drifters and acoustic Doppler current profilers placed on buoys and at the bottom, have some disadvantages. These are 1) measurement limitations in case of large areas; 2) high measurement costs; 3) limitations of weather conditions. Conventional microwave radars provide oceanographic and meteorological information at the distances below 50 miles. Satellite systems give only episodical control during their flight since the orbit frequency is too low. The measurements using aircraft radars cannot be continuous.
The existing and currently developing local and regional oceanographic HF radar networks allow investigating large ocean patches permanently and with low costs. HF radars are usually placed at the coast and provide measurements of surface currents, waves and wind by analyzing power spectra of radar signals, which are backscattered by the sea surface. They have the ability to observe hydrometeorological environment, to provide ecological monitoring and disaster warning in the offshore area. Continuous and all-weather (independently of snow, rain, fog or clouds) operation of the HF radar allows monitoring the sea surface over large areas and getting information from the distances up to 200-300 km from a coastline. Moreover the costs of HF radar monitoring per square km of the sea surface is twice lower the ones for contact methods or satellite measurements.
Presently there are three main oceanographic applications of HF radar: 1) surface current measurements and mapping, including multilayer mapping to describe the depth changes of current speed; 2) non-symmetric spatial spectrum reconstruction for sea states, wave lengths, dominant wave periods, general direction of wave propagation, significant wave height mapping; 3) wind direction and wind speed reconstruction and mapping. All the above mentioned applications are extremely important for the safety and economy of shipping.
HF surface wave radar is a prospective tool to monitor coastal areas in real time. It reports about meteorological and hydrographical environment, approaching storms and tsunami to the economically important coastal area.