不同风向对珠江东四口门盐水入侵的影响

采用MIKE3构建珠江东四口门三维水动力数值模型,对枯水期各风向下珠江口的水动力进行模拟,分析北风、东北风和东风对河口涨落潮流速、盐度分布、潮通量的影响。结果表明:表层和底层水体的涨落潮流速变化在风的作用下是相反的。北风促进虎门垂向环流的发展,使小潮期垂向净环流出现频次增加且环流强度增大,导致口门内盐水入侵距离增大,垂向平均盐度增大,东北风的影响与北风相似但幅度较小,东风则相反。北风、东北风使东四口门涨潮量减少,东风使涨潮量增加,落潮量的变化则不仅与风向相关,还与河道走向、垂向环流有关,因此4个口门的落潮量对风的响应有所不同。风的持续作用对虎门盐水入侵影响较大,对其他三口门影响相对较小。

Influence of different wind direction on saltwater intrusion in East four portals of Pearl River

MIKE3 was used to build a three-dimensional hydrodynamic numerical model of the East four portals of the Pearl River, which simulated the hydrodynamic forces of the Pearl River Estuary under different wind directions in the dry season, and analyzed the influence of the north wind, northeast wind and east wind on current velocity of rising and falling tide, salinity distribution and tidal flux of the estuary. The results show that the velocity change of rising and falling tide of surface and bottom water is opposite under the action of wind. The north wind promotes the development of the vertical circulation in Humen, increases the frequency and intensity of the vertical net circulation in neap tide, and results in the increase of the saltwater intrusion distance and the vertical average salinity in Humen. The influence of the northeast wind is similar to that of the north wind, but the range is smaller, while the east wind is opposite. The north and northeast winds reduce the tide rise of the East four portals, while the east wind increases the tide rise. The variation of falling tide is not only related to the wind direction, but also to the channel trend and vertical circulation. Therefore, the response of the falling tide to the wind is different in the East four portals. The lasting effect of wind on the saltwater intrusion of Humen is greater than that of the other three.