渤海夏季环流结构研究

发布时间：2018-12-22 08:09

【摘要】：本文利用渤海2006年夏季温度和盐度大面观测资料,通过WKB近似和数值方法计算了渤海夏季第一斜压罗斯贝变形半径的分布。第一斜压罗斯贝变形半径是表征能否建立起地转平衡关系的临界尺度,在此基础上经过浅水订正,计算了渤海夏季地转流流场。结果表明,海流经渤海海峡北部进入渤海,至渤海中部,流动发生弯曲向北行进,最终在渤海中部对应着混合均匀的高温水的位置,形成一个顺时针的正压的环流,该环流中心位于120.5°E,39°N,半径约为50~60km,流速约为10cm/s。在长兴岛以西的辽东湾海域,有一逆时针的环流。该环流中心位置为120.8°E,39.7°N,半径约为60~70km。在该流环的东北有一分支流沿辽东湾东岸北上,经辽东湾北部向西折,与辽东湾沿岸流相接,最终沿湾西岸南下。在黄河口外海域,有一支海流指向北-东北方向,汇入由渤海海峡流入的渤海的高盐水系中,至滦河口附近西折回流,在渤海湾口形成逆时针环流。该环流中心位于119.2°E,38.8°N附近,流环呈椭圆结构,南北向的长半轴约为50~60km,东西向的短半轴约为15~30km。在莱州湾,有一弱的顺时针的环流。在北戴河和长兴岛附近海域,第一斜压罗斯贝变形半径最大。在渤海中部等值线发生明显弯曲,在靠近渤海海峡内侧出现一个小值,而与之对应在渤海中部以西出现一个大值。这些极值区域刚好对应着渤海的三个环流,分别是辽东湾中部的逆时针环流、渤海中部的顺时针环流、和渤海湾口以东的逆时针环流。极值区的第一斜压罗斯贝变形半径的量值均小于环流半径的量值,在地转调整中,海面高度变化在调整过程中的尺度与罗斯贝变形半径相比为大量,科氏力同压强梯度力共同支配流的运动的状态达到动态平衡,因此计算得出的渤海夏季环流结构是合理可靠的。
[Abstract]:In this paper, the distribution of the first baroclinic Rossby deformation radius in the Bohai Sea in summer is calculated by WKB approximation and numerical method using the large surface temperature and salinity observation data of the Bohai Sea in the summer of 2006. The first baroclinic Rossby deformation radius is the critical scale to indicate whether the geostrophic equilibrium relationship can be established. On this basis the geostrophic flow field in the Bohai Sea in summer is calculated through shallow water correction. The results show that the sea flows through the north of the Bohai Strait into the Bohai Sea and reaches the middle of the Bohai Sea. The flow bends northward and finally corresponds to the position of the mixed high temperature water in the middle of the Bohai Sea, forming a clockwise barotropic circulation. The center of the circulation is located at 120.5 掳E ~ (39) 掳N, the radius is about 50 ~ 60 km, and the velocity of flow is about 10 cm / s. In the Liaodong Bay to the west of Changxing Island, there is an anti-clockwise circulation. The center of the circulation is 120.8 掳E ~ (2 +) 39.7 掳N and the radius is about 6070 km. In the northeast of the current ring, one tributary goes north along the east coast of Liaodong Bay, then bends westward through the northern part of Liaodong Bay, meets the coastal current of Liaodong Bay, and finally goes south along the west coast of Liaodong Bay. In the waters outside the Yellow River estuary, there is a current pointing north to northeast, which flows into the high salt water system of the Bohai Sea from the Bohai Strait, and then flows back to the west near the Luanhe River Estuary, and forms counterclockwise circulation at the Bohai Bay mouth. The circulation center is located around 38.8 掳N of 119.2 掳E ~ (2 +). The flow ring is elliptical. The long half axis in the north and the south direction is about 50 ~ 60 km, and the short half axis in the east-west direction is about 1530 km 路m ~ (-1). In Laizhou Bay, there is a weak clockwise circulation. In the sea area near Beidaihe and Changxing Island, the first baroclinic Ross Bay has the largest deformation radius. In the middle of the Bohai Sea, the contour curve is obviously curved, and a small value appears near the inner side of the Bohai Strait, and a large value is corresponding to the west of the central Bohai Sea. These extreme regions are exactly corresponding to the three circulation in the Bohai Sea, namely, the counterclockwise circulation in the middle of Liaodong Bay, the clockwise circulation in the middle of the Bohai Sea, and the counter-clockwise circulation in the east of the Bohai Bay mouth. The values of the first baroclinic Rossby deformation radius in the extreme region are smaller than those of the circulation radius. In the geostrophic adjustment, the scale of the sea surface height variation in the adjustment process is much larger than that of the Rossby deformation radius. The movement state of the current dominated by Coriolis force and pressure gradient force is in dynamic equilibrium, so the calculated circulation structure in the Bohai Sea in summer is reasonable and reliable.
【学位授予单位】：国家海洋局第一海洋研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P731.27

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