长江口外近岸环流对厄尔尼诺事件的响应

Anomaly response to El Nio events of nearshore circulation off Yangtze Estuary

建立了东中国海环流大模型,在此基础上建立包含长江口、杭州湾及邻近海域在内的区域环流模型,较准确地刻画东中国海外海流系和沿岸流系,以及长江口外精细的流系结构。选择典型厄尔尼诺年,模拟长江口外近岸环流的异常变化,探讨长江口外近岸环流与厄尔尼诺事件的响应关系。研究表明:长江口外近岸环流与厄尔尼诺事件存在强烈的响应关系,冬季厄尔尼诺现象发生时长江口及邻近海域的环流明显减弱;台湾暖流受厄尔尼诺事件影响程度显著,流速减小、流幅变窄,台湾暖流对长江口外近岸环流的影响也因此减弱。

In this study, an East China Sea circulation model was built. Based on this, a small-scale circulation model including the domain of the Yangtze Estuary, Hangzhou Bay, and adjacent water areas was built. With this model, the oceanic current system and coastal current system of the East China Sea, and the flow structure off the Yangtze Estuary were accurately simulated. In order to study the anomalies, typical El Nino years were chosen to analyze the response relationship between the nearshore circulation off the Yangtze Estuary and El Nino events. The results show that there was a significantly responsive relationship between the nearshore circulation off the Yangtze Estuary and El Nino events. In the winter, the circulation at the Yangtze Estuary and adjacent water areas weakened significantly when the El Nino phenomenon occurred. The Taiwan warm current was greatly affected, with decreased flow velocity and narrowed flow amplitude, which weakened the impact of the Taiwan warm current on the nearshore circulation off the Yangtze Estuary.