| ZHU Ping,WU Hui. 2018. Origins and transports of the low-salinity coastal water in the southwestern Yellow Sea. Acta Oceanologica Sinica, 37(4):1－11 |
| Origins and transports of the low-salinity coastal water in the southwestern Yellow Sea |
| 西南黄海近岸低盐水体的来源与输送机制 |
| Received:September 17, 2017 |
| DOI：10.1007/s13131-018-1200-x |
| Key words:Subei Coastal Water origins river plume numerical modeling |
| 中文关键词: 苏北低盐水 来源 长江冲淡水 数值模拟 |
| 基金项目:The National Natural Science Foundation of China under contract No. 41576088; the National Key Research and Development Program of China under contract No. 2016YFC1402202; the research foundation of State Key Laboratory of Estuarine and Coastal Research under contract No. 2015KYYW04. |
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| Abstract: |
| In the southwestern Yellow Sea there is a low-salinity and turbid coastal water, the Subei Coastal Water (SCW). The origins of freshwater contents and thus the dissolved terrigenous nutrients in the SCW have been debated for decades. In this study, we used a well-validated numerical model to quantify the contributions of multiple rivers, i.e., the Changjiang River in the south and the multiple Subei local rivers (SLRs) in the north, in forming this year-round low-salinity coastal water. It is found that the freshwater contents in the SCW is dominated by the Changjiang River south of 33.5°N, by the SLRs north of 34.5°N, and by both sources in 33.5°-34.5°N. Overall, the Changjiang River contributes~70% in the dry season and~80% in the wet season of the total freshwater contents in the SCW, respectively. Dynamics driving the Changjiang River Plume to flow northward is the tidal residual current, which can even overwhelm the wind effects in winter seasons. The residual currents turn offshore near the Old Yellow River Delta (OYRD) by the collision of the two tidal wave systems, which transport the freshwater from both sources into the interior Yellow Sea. Water age experiments show that it takes 50-150 d for the Changjiang River Plume to reach the SCW in the spring and summer seasons, thus there is a 2-month lag between the maximum freshwater content in SCW and the peak Changjiang River discharge. In the winter and autumn seasons, the low salinity in inner SCW is the remnant Changjiang River diluted water arrived in the previous seasons. |
| 中文摘要: |
| 西南黄海海域是一个低盐和浑浊的水域，通常也称作苏北海域。多年来，该海域河流冲淡水及其携带物质的主要来源一直充满着争议。位于该海域南侧的长江和主要分布在北侧的众多苏北地方河流都被认为是可能的来源。本研究利用一个充分验证的数值模型，模拟研究了两个淡水来源分别对苏北低盐水形成的贡献。结果表明，在33.5°N以南的苏北水域长江是主要的淡水来源，34.5°N以北苏北地方河流是主要淡水来源，在两者之间则受到两个来源的共同影响。总体而言，冬季苏北海域70%的冲淡水来自长江，夏季这一比例则上升到了80%。导致长江冲淡水输送到苏北海域的机制是北向潮致余流，该潮致余流在秋冬季节甚至可以抵消南向风生流的作用。受东海前进潮波系统和黄海旋转潮波系统在废黄河口附近辐聚的影响，苏北水域北向潮致余流到达废黄河口附近后转为离岸运动，将来自于长江和苏北地方河流的冲淡水一并输送往黄海内部。水龄数值模拟实验显示，春夏两季长江冲淡水从长江口到达苏北水域的时间尺度为50-150天。因此，苏北水域长江淡水含量的峰值要落后于长江径流峰值约2个月。在秋冬季节，苏北水域的长江冲淡水主要为前期长江冲淡水的残留。 |
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