日本海中央部の海上風と有義波の変動特性

概要

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The variability of the sea surface winds and waves in an open area of the Japan Sea was investigated based on the data from 1990 to 1998 obtained at the JAM buoy moored at ($37^\circ 55'$N, $134^\circ 33'$E), just as was done based on the data off Tsuyazaki, Fukuoka, close to the coast. The wind speed and significant wave height showed seasonal cycles analogous to those off Tsuyazaki: high in winter and low in summer with their annual means of 6.74 m/s and 1.44m, respectively. The significant wave period, however, had a slightly reversed seasonality: it was the shortest in winter and the longest in summer with the annual mean of 8.0 sec. The scatter diagram of significant wave heights against significant wave periods suggests that most of significant wave heights are limited by an upper bound corresponding to a constant wave steepness. This fact agrees with our previous finding for the waves off Tsuyazaki, though the upper bound itself might differ somewhat from that observed off Tsuyazaki. As regards the frequency spectrum form the periods of a few days to a few hours, significant wave heights and significant wave periods as well as winds had the same spectral form proportional to the frequency to the $-5/3$ power, again in agreement with another finding for the data of Tsuyazaki.
2000-06-30