Oceanographic observation in hyuga-nada by the high-frequency ocean radar

High-Frequency (HF) ocean radar obtains hydrographie information as current velocities by analyzing backscattered Bragg resonance from sea surface and is suitable to observe the coast area. Hyuga-Nada is the eastern area off Miyazaki prefecture in Kyusyu island. The Kuroshio current approaches this area and it affects the sea condition and fishery, so it is improved to monitor the coast area. We observed this area by HF ocean radar and got the first-order peaks corresponding to Doppler frequency of the phase velocity satisfied Bragg resonance conditions. Also there are the two spectral peaks within a radar footprint area. This implies that there are two different flows in this area and it seems to be appeared a shear front or an eddy in a radar footprint. In the observation period, these two-peak spectra appear but don't always in the specific distance. It may be related to the distance from the Kuroshio current or the direction of sea wind.