长江口北支地形变化对倒灌盐水的影响

Effect of Topographic Change on Inverted Brine in North Branch of the Yangtze Estuary

摘要:

北支盐水入侵是长江口径潮动力的重要特征，受到径流、潮汐以及地形变化等多方面的影响。通过建立长江口潮流盐度模型，讨论不同地形条件对长江口北支潮位及盐水倒灌量的影响，研究倒灌盐水团的活动规律和盐度的变化。研究表明：2000—2017年期间年地形变化使得北支倒灌明显减弱，中缩窄方案实施完成后将使得倒灌现象进一步减弱；地形改变造成的倒灌盐水量的变化对在南支活动的倒灌盐水团的盐度有显著的影响，但对盐水团在南支的活动规律影响较小。

Abstract:

The brine intruding from the north branch is an important feature of river tide dynamics in the Yangtze Estuary, which is affected by runoff, tide and topographic change. Through the establishment of flow and salinity model of the Yangtze Estuary, the influence of different topographic conditions on the tidal level and brine flow backward in the north branch of the Yangtze Estuary is discussed, and the activity rule and salinity change of the inverted brine group are studied. The study shows that the annual topographic changes during 2000—2017 made the flow backward in the north branch significantly weakened. The middle constriction scheme after implemented will make the flow backward phenomenon further weakened. The variation of inverted brine caused by the topographic change has the significantly influence on the salinity of the inverted brine group in the north branch, but has a little influence on the activity rule of brine group in the south branch.