中文摘要：

鄱阳湖与长江之间存在着复杂的相互作用关系,决定着江湖水沙交换,对整个区域的水资源、防洪、航运、生态环境等均具有重要影响。本文基于能量的观点,在从新的角度解释鄱阳湖和长江相互作用原理的基础上,构建了江湖相互作用的表征指标—能差Fe,对20世纪50年代以来江湖作用关系变化进行了研究。结果表明,自20世纪50年代以来,Fe值整体呈现增加趋势,说明长江作用减弱,鄱阳湖作用不断增强。三峡水库蓄水运用对江湖关系产生了重要影响,进一步削弱了长江作用。从年内变化来看,由于三峡水库的调节,枯水期长江作用略有增强,汛末长江作用减弱较大。江湖作用一定程度上影响着湖区旱涝灾害的产生,当五河来流较大且长江顶托作用明显时,易发生洪涝;当五河来流较小但又对长江有明显的补水作用时,易发生旱情,三峡水库蓄水使湖区9-10月更易发生干旱。

英文摘要：

The complicated relationship between the Yangtze River and Poyang Lake is the factor determining the exchange of water and sediment between them and has great influence on the water resources, flood control, navigation, and ecological environment of the entire region. Based on the theory of energy, this paper explains the principle of the river-lake relationship from a new perspective. By constructing a new index Fe, the authors were able to analyze the evolution of the relationship between the Yangtze River and Poyang Lake since the 1950s. The results indicate that the value of Fe shows an increasing trend, which means the river effect is weakening while the lake effect is strengthening. Operation of the Three Gorges Dam has an important impact on the river-lake relationship, which further weakens the river effect. The river effect increases slightly in the dry season but decreases significantly at the end of the flood period. In addition, the relationship between the Yangtze River and Poyang Lake may induce drought and flood disasters to some degree. Flooding is more likely to occur when flow from the five tributaries of the Poyang Lake is large and the Yangtze River blocking effect is strong. In contrast, drought is more likely to occur when flow from the five tributaries of the Poyang Lake is small, while the lake effect is strong. Meanwhile, the probability of drought in the Poyang Lake from September to October increases due to the impounding of the Three Gorges Reservoir.