短波海洋レーダで計測した八重山列島北方の潮流

Tidal currents north of the Yaeyama Islands, Japan, are observed by HF radars. They are compared with results of a numerical tidal model. Although amplification of the speed on the continental shelf is qualitatively confirmed in both results, those currents are generally not similar. Most part of the discrepancies would be due to errors in the HF radar velocity products, but also the model results include suspicious features near complex bottom topography on the continental shelf. Tidal currents estimated from the HF radar data in summer are slightly different from ones from the winter HF radar data. The seasonal difference is larger in diurnal tides rather than semi-diurnal tides, which would suggest that they could be related to the seasonal variation of the atmospheric tides.