Influence of the Oyashio Current and Tsugaru Warm Current on the circulation and water properties of Otsuchi Bay, Japan
Influence of the Oyashio Current and Tsugaru Warm Current on the circulation and water properties of Otsuchi Bay, Japan
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DOI：
10.1007/s10872-016-0383-z
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发表时间：
2017-02-01
影响因子：
2.3
通讯作者：
Komatsu, Kosei
中科院分区：
文献类型：
--
作者：
Ishizu, Miho;Itoh, Sachihiko;Komatsu, Kosei
2012年9月至2014年5月，在日本太平洋沿岸沿着的大槌湾口进行了系泊和水文观测。观测结果表明，大槌湾的环流和水质在季节和亚季节尺度上都受到津轻暖流（TWC）和亲潮海流（OY）的强烈影响。两个底部安装的速度廓线和温度和盐度测量近地表盐跃层下显示逆时针横向环流模式TWC，这是从夏季到秋季增强。从冬季到早春，与TWC有关的侧环流形势减弱，OY的影响偶尔增强。当OY较弱时，地面气流形成上层出流，下层入流的翻转结构。当OY强度增强并从三陆海岸附近经过时，环流变得高度多变且时断时续。入侵的显着低盐度的OY水观察了两次，并持续了几个星期到几个月的时间。盐度有时低于33.7，典型的TWC的下限从夏末到秋季，即使当TWC占主导地位。我们认为，这是TWC本身的季节性波动，因为对马暖流的上游流在夏季由于长江的影响而变淡。海湾南部的地表水通常比北部的新鲜，这表明河流羽流的科里奥利偏转。
Mooring and hydrographic observations were conducted from September 2012 to May 2014 at the mouth of Otsuchi Bay, a ria along the Pacific coast of Japan. Our observations quantitatively demonstrated that the circulation and the water properties of Otsuchi Bay are strongly influenced by the Tsugaru Warm Current (TWC) and Oyashio Current (OY) at seasonal and subseasonal time scales. Two bottom-mounted velocity profilers and temperature and salinity measurements beneath the near-surface halocline showed a counterclockwise lateral circulation pattern related to the TWC, which was enhanced from summer to autumn. From winter to early spring, the lateral circulation patterns related to the TWC weakened and the influence of the OY occasionally increased. When the OY was weak, surface flows became an overturning structure, with outflows in the upper layer and inflows in the lower layer. When the OY was strong and passed close to the Sanriku coast, the circulation became highly variable and intermittent. Intrusions of the markedly low-salinity OY water were observed on two occasions and persisted for periods of several weeks to several months. Salinity was sometimes less than 33.7, the lower limit of the typical TWC from late summer to autumn even when the TWC dominates. We suggested that this is the seasonal fluctuations of the TWC itself, as the upstream current of the Tsushima Warm Current is freshened in summer as a result of the influence of the Changjiang River. The surface water was generally fresher in the south of the bay than in the north, suggesting the Coriolis deflection of the river plume.