北海道大学水産科学研究彙報 = Bulletin of Fisheries Sciences, Hokkaido University;第57巻 第1/2号

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富山湾における数日周期の風強制流速変動

相木, 智一;磯田, 豊;小善, 圭一

Permalink : http://hdl.handle.net/2115/32481
KEYWORDS : Toyama Bay;current variation;wind forcing;internal Kelvin wave;bottom-trapped shelf wave

Abstract

Two-layer current measurements were carried out at the bay-head over the shelf of the Toyama Bay,from 24 February to 13 March 2002. The upper was set at 100m and lower at 300 m below the sea surface. Current fluctuations caused by wind variation with several-day period are observed. It is found that the phase difference between upper and lower current variations shows about 90 degree. Such fluctuations cannot be explained by a single baroclinic coastal-trapped wave (out of phase) and barotropic one (in phase). So, the generation and propagation of several-day period fluctuations forced by wind were investigated by using the numerical two-layer model. In result, the observed current fluctuations can be reasonably explained by two-type coastal-trapped waves simultaneously excited mainly by north-south wind variations. One is internal Kelvin wave propagated in the upper layer with phase velocity of about 1ms-1 and the other is the bottom-trapped shelf wave slowly propagated with phase velocity of about 0.25 ms-1.

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