| 摘要: |
| 利用σ坐标系下的斜压浅海环流模式，研究M2分潮对夏季长江冲淡水扩展的影响。在“准定常流”作用下，模拟出能反映夏季长江冲淡水扩展的盐度场，并模拟出与黄、东海实测资料相符的M2分潮。在此基础上，用两种方案讨论M2分潮对冲淡水的影响。第一种方案，仅考虑M2分潮，计算它对冲淡水扩展的影响；第二种方案，将M2分潮和“准定常流”耦合，计算冲淡水扩展的变化。结果表明，M2分潮对冲淡水扩展有一定影响，其中包括潮混合和定向输运。 |
| 关键词: M2分潮 长江冲淡水 潮混合 定向输运 |
| DOI： |
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| 基金项目:华东师范大学河口海岸国家重点实验室开放基金项目和总参气象局资助项目 |
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| A NUMERICAL STUDY ON THE IMPACT OF M2 TIDE ON THE EXPANSION OF THE CHANGJIANG RIVER DILUTED WATER IN SUMMER |
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ZHU Shou-xian1, ZHU Jian-rong2, SHA Wen-yu1
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1.Military Meteorology Department of the Army Sceience and Technology Universitr Nanjing, 211101;2.State Key Laboratory of Estuarine and Coastal Research, Training College of Huadong, Shanghai, 200062
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| Abstract: |
| The objective of this work was to study the M2 tide's impact on the expansion of Changjiang River diluted water. The calculation was done with a baroclinic and shallow water model inσcoordinate system. The selected domain included the Bohai, Yellow, and East China Seas. The horizontal resolution is 7.5′×7.5′. The model had 11 layers. The quasi-steady current was simulated first, which was affected by the boundary forces, the summer wind, and the baroclinic mechanism. The expansion of the Changjiang River diluted water in summer can be described by the salinity field resulted from the quasi-steady current. Then, the M2 tide in the Yellow Sea and the East China Sea was simulated. The results agreed with the observed data. Based on these studies, two ways were adopted to study the M2 tide's impact on the diluted water. The M2 tide was first considered individually to calculate its impact on the expansion of the diluted water. When the calculated current of M2 tide was steady, the salinity field induced by the quasi-steady current was taken as the initial field to be calculated with the M2 tide's current. Then, coupling M2 tide with quasi-steady current, the change of the diluted water's expansion was studied numerically. Taking the quasi-steady current as the initial field, and keeping the wind and the baroclinic mechanism, the calculation of current was carried based on the water level on the open boundaries, which was the superposition of that of the M2 tide and the quasi-steady current. When the change patterns of currents between two tidal periods were the same, the salinity was also calculated. The initial salinity field was induced by the quasi-steady current. These calculations indicated that M2 tide had impact on the Changjiang River diluted water's expansion in summer, which involved tidal mixing and tidal transport.
Mixing accelerated the diluted water's diffusing to the Yellow Sea and the East China Sea in all directions.
Transport was northward near the Changjiang River mouth, and southward far away from the mouth, but was northward again around Jizhou Island. |
| Key words: M2 tide, Changjiang River diluted water, Tidal mixing, Tidal transport |
