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为对长江口南支河段盐水入侵规律有清晰的认识,在梳理、总结以往研究成果的基础上,通过对历年咸潮及氯度实测资料的分析,对长江口南支河段盐水入侵的规律进行了较为全面系统的分析研究。研究表明:北支盐水倒灌是长江口南支河段盐水入侵的主要来源;在研究水域,枯季大潮期氯度的沿程分布表现为两头高、中间低的“马鞍形”形式,枯季中潮期则为“高-低-高-低-高”的复杂的“W”形的分布形式;受外海潮汐和上游径流的综合作用,由大潮到中潮,倒灌盐水团在下移过程中,氯度的沿程分布形式发生了变异;近期盐水入侵的程度有加剧的趋势;研究水域2～3月盐水入侵最严重,在这段时间内盐水入侵超标次数多、历时长;当大通流量小于20 000m3/s时,就可能发生明显的北支盐水倒灌南支现象;盐水入侵程度跟大通流量和潮汐强度密切相关;大通流量越大,盐水入侵程度越低;潮差越大,盐水入侵程度越高。
In order to get a clear understanding of the saltwater intrusion in the Nanzian reach of the Yangtze River estuary, based on the previous research results, the saltwater intrusion in the Nanzian reach of the Yangtze Estuary The law conducted a more comprehensive and systematic analysis. The results show that the main source of salt water intrusion in the Nanzian reach of the Yangtze River estuary is the salt water intrusion in the northern part of the Yangtze River. In the study waters, the distribution of the chlorinity along the dry season is characterized by “high” and “low” saddle “ The tidal period in the dry season is a complex ”W“ -shaped distribution pattern of ”high-low-high-low-high"; from the tide to the mid-tide, In the process of downward movement, the variation of the distribution of chlorinity has taken place. The degree of recent salt water intrusion has been aggravating. The saltwater intrusion from September to March was the most serious in the study area. During this period, ; When the flow of Chase is less than 20 000 m 3 / s, the south branch of the northern branch of saline water intrusion may occur obviously. The degree of salt water invasion is closely related to the flow and tide intensity of the chase; the larger the flow of the chase is, the lower the degree of salt water invasion is; Large, the higher the degree of salt water invasion.