The seasonal circulation of the upper ocean in the Bay of Bengal
The seasonal circulation of the upper ocean in the Bay of Bengal
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DOI：
10.1029/91jc01045
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发表时间：
1991-07
影响因子：
--
通讯作者：
J. Potemra;M. Luther;J. O'Brien
中科院分区：
文献类型：
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作者：
J. Potemra;M. Luther;J. O'Brien
由气候月平均风驱动的印度洋上层绝热多层数值模式的结果分析表明，模拟的印度洋东北部海流与已有的观测和解释基本一致。洋流的主要特征包括北半球冬季孟加拉湾表层水域的大规模反气旋流动。这个旋涡在春天衰变成漩涡，然后在夏末转变成一个较弱的气旋式旋涡。该气流的西侧回流区是一股强化的西侧边界流，全年有两次转向。在孟加拉湾以东的安达曼海，洋流在一年中两次改变方向；春季和初夏为气旋，其余时间为反气旋。赤道地区的气流表现为冬季北赤道流(NEC)向西流动。再往南是向东流动的赤道逆流(ECC)和向西流动的南赤道流。在夏季，NEC改变方向，加入ECC，形成印度季风流。对模式第二层(海洋上部450米)的研究表明，一年中大部分时间的气流是斜压的(强垂直切变)。模型层厚度揭示了沿海开尔文波沿着海岸传播，穿过安达曼海和孟加拉湾的整个周长。该波激发向西传播的Rossby波进入海湾内部。对运输计算的时间序列分析得出了20至30天范围和50至60天范围内的显着峰值，这些峰值不太可能是所施加的风应力直接迫使的。
Analysis of the results of a multilayer, adiabatic, numerical model of the upper Indian Ocean, driven by climatological monthly mean winds, shows that the simulated currents in the northeastern Indian Ocean are in general agreement with available observations and interpretations. The main features of the ocean currents include large anticyclonic flow in the Bay of Bengal surface waters during the northern hemisphere winter. This gyre decays into eddies in spring and then transitions into a weaker, cyclonic gyre by late summer. The western recirculation region of this flow is an intensified western boundary current which changes direction twice during the year. In the Andaman Sea, east of the Bay of Bengal, the oceanic flow changes direction twice during the year; it is cyclonic during the spring and early summer and anticyclonic the rest of the year. Flow in the equatorial region shows the North Equatorial Current (NEC) flowing west during winter. Further south is the eastward flowing Equatorial Counter Current (ECC) and the westward flowing South Equatorial Current. In summer, the NEC switches direction, joins the ECC, and forms the Indian Monsoon Current. Investigation of the second layer of the model (the upper 450 m of the ocean) shows that flow during much of the year is baroclinic (strong vertical shear). Model layer thickness reveals coastal Kelvin waves propagating along the coast, traveling the entire perimeter of the Andaman Sea and the Bay of Bengal. This wave excites westward propagating Rossby waves into the interior of the bay. Time series analysis of transport calculations yield significant peaks in the 20- to 30-day range and 50- to 60-day range which are not likely directly forced by the applied wind stress.