摘要: |
由华东师范大学朱建荣和沈焕庭完成的20万字的《长江冲淡水扩展机制》专著,已于1997年3月由华东师范大学出版社出版发行。该专著是第一部建了一个σ坐标系下三维非线性斜压浅海与陆架模式、考虑多种动力因子、研究长江冲淡水扩展的专著。夏季长江冲淡水转向机制是物理海洋学界多年来悬而未决的问题,长期以来为国内外同行所瞩目。以往研究的方法,大多数是基于对观测资料的分析;对采用的一些数学模型,为了能求出其解析解,做了过多的近似,能够考虑的因子很有限;数值模式不够完善,考虑的因子也不够全面。著者在充分了解国内外研究动态的基础上,根据长江口外海区复杂的自然条件,设计了一个σ坐标系下三维非线性斜压原始方程浅海与陆架模式,在模拟出渤、黄、东海稳定环流的基础上,考虑各种因子的作用,以内在动力机制上比较全面、深入地研究长江冲淡水的扩展机制,得出了一些重要的结论。这是该专著的最大特色和创新之处。 |
关键词: 长江冲淡水扩展 扩展机制 数值模拟 陆架模式 长江冲淡水转向 三维非线性 水平压强梯度 台湾暖流 物理海洋学 动力分析 |
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THE EXPANSION PROCESSES OF THE CHANGJIANG”RIVER DILUTED WATER |
Qin Zeng-hao
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Shanghai Typhoon Institute, Shanghai, 200030
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Abstract: |
Authored by the Chinese oceanographers Zhu Jianrong and Shen Huanting, the members of the State Key laboratory of Estuarine and Coastal Research, the monograph entitled “THE PROCESSES OF THE EXPANSION OF THE CHANGJIANG DILUTED WATER" with 200000 Chinese words, was published by the East China Normal University Press in March 1997. It is the first monograph in which a three-dimension nonlinear baroclinic shallow water and continental shelf model in σ-coordinate system was developed to study the dynamic processes of the expansion of the Changjiang River diluted water (ECDW).
The model calculation domain covered the Bohai Sea, Yellow Sea and East China Sea, and had fine horizontal and vertical resolutions of 7.5' × 1.7' and 11 layers. The altemating direction implicit computational scheme was adopted for the numerical solution of the model equation.
Since the ECDW was closely related to the residual currents induced by the boundary forces and wind, density current and tide induced residual currents in the sea area outside Changjiang River mouth, the residual currents were numerically simulated and their potential impacts on the ECDW were separately considered. The impacts exerted by the bottom topography, baroclinicity and their interaction on the ECDW were simulated numerically, and the computational results were further analyzed dynamically in terms of the vorticity equation involving the bottom topography, water level slope, and their interaction with baroclinicity.
The main focus in this monograph was placed on the summertime ECDW, especially its turning direction. The influence of factors such as runoff, Taiwan Warm Current, wind field, Yellow Sea Cold Eddy, on the wintertime ECDW was numerically and dynamically analyzed in detail and numerically simulated. The simulations showed that the Changjiang diluted water turned northeastward in summer and expanded southward along the coast in a narrow band in winter. The circulation structures of the East China Sea in summer and winter were reconstructed, and new ideas and interesting results were obtained in this study. The authors pointed out that the Yellow Sea Cold Eddy and the wind field play important roles in turning the direction of the Changjiang diluted water in summer, whereas the Taiwan Warm Current and Changjiang River runoff cannot affect its turning direction. Resulting mainly from the bottom configuration and baroclinicity and their interaction, the summertime Changjiang diluted water is characterized by a jet-like stream near to the river mouth.
This book presents a new viewpoint on the summertime ECDW which differed from that the traditional one and has high scientific valus for people who want to understand the processes of the ECDW. |
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