Radar (WERA): a new ground-wave HF radar for ocean remote sensing

HF radars can be used to measure surface currents and wave spectra. The Coastal Radar (CODAR) used by the University of Hamburg was designed for current map-ping only. It has been operated for some 15 field experiments during the past 15 years. Recently, a new HF radar called WERA (Wellen Radar) has been developed at the University of Hamburg. One main advantage of the system is the possibility of connecting different configurations of receive antennas. When operated with a linear array, information on the sea state can be obtained via second-order spectral bands. A further advantage is the flexibility in range resolution between 0.3 km and 1.2 km, instead of the fixed resolution of about 2 km of CODAR. This is achieved by transmitting frequency-modulated continuous wave (FMCW) chirps instead of continuous wave (CW) pulses. In addition, this technique avoids the blind range of about 3 km in front of the CODAR. The technical design of WERA is described and first experimental results are presented. Key words: Ocean remote sensing, HF radar, surface current.