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长江中游自然通江的洞庭湖和鄱阳湖,在长期的季风气候以及江湖交互作用下形成了相对稳定的涨-丰-退-枯季节性水位波动模式。近几十年来,受水利工程及气候变化的双重影响,两湖季节性水情均发生了显著改变。揭示和对比两湖季节性水位波动近年来的变化趋势及强度并分析其形成的可能原因,对于指导两湖地区的湖泊管理与实践,理解长江中游江湖关系演变现状具有重要意义。基于此,以2003年为断点(即1980~2002年与2003~2014年两时段),首先通过湖区多站点水文要素的单因素方差分析揭示两湖各自的季节性水情变化特征;然后通过两湖季节性水情变化状况的对比,分析长江中游大型通江湖泊水情变化的规律及其形成原因。得出的主要结论如下:(1)2003年后,涨水期和枯水期的两湖水情均呈偏枯趋势,且水位降幅均在由上游到中游的过程中扩大,由中游到下游的过程中减小,甚至涨水和枯水期的洞庭湖下游湖区还出现了水位的小幅抬升。(2)2003年后,丰水期和退水期的洞庭湖偏枯趋势呈现不同的空间分异,丰水期的洞庭湖水位下降程度在上、中游湖区更为剧烈,而退水期的水位下降程度在中、下游湖区更为剧烈。与此同时段的鄱阳湖偏枯趋势在丰水期和退水期均在由上游至下游的过程中增加。(3)2003年后的洞庭湖水位降幅在各个季节各个湖区均显著小于位于其下游的鄱阳湖。江湖关系对两湖及其不同湖区的作用方式和强度的差异是造成两湖季节性水情演变差异的主要原因。
The Dongting Lake and Poyang Lake, which pass through the middle reaches of the Yangtze River, form a relatively stable seasonal fluctuation pattern of the up-down-return-dryness under the long-term monsoon climate and the interaction between rivers and lakes. In recent decades, due to the double impact of water conservancy projects and climate change, the seasonal water regimes in both lakes have undergone significant changes. Revealing and comparing the trend and intensity of seasonal fluctuation of water level in two lakes in recent years and analyzing the possible reasons for the formation are of great significance in guiding the management and practice of lakes in the two lakes and in understanding the evolution of the relations between rivers and lakes in the middle reaches of the Yangtze River. Based on this, taking 2003 as the breakpoint (ie 1980-08 and 2003-2014), we first reveal the seasonal changes of the two rivers by single factor analysis of variance of multi-site hydrological factors in the lake area. Seasonal changes in the situation of water conditions, the Yangtze River in the large rivers and lakes of water changes in the law and its formation causes. The main conclusions reached are as follows: (1) After 2003, the hydrological conditions of both lakes in dry-up and dry-water periods all showed a partial dry-wet trend, and the decrease of water level both expanded from the upper reaches to the middle reaches, from the middle reaches to the lower reaches Small, even water and dry season in the lower reaches of Dongting Lake also showed a slight rise in water level. (2) After 2003, the tendency of partial dry-up of Dongting Lake in wet season and retreat period showed different spatial differentiation. The water level of Dongting Lake in wet season dropped to the upper level, and the lake in middle reaches was more intense, while the water level in retreat stage Decline in the middle and lower reaches of the lake more intense. In the meantime, the tendency of Poyang Lake partial weakening increased during the wet season and the return period from the upper reaches to the lower reaches. (3) The decrease of Dongting Lake water level after 2003 is significantly smaller than that of Poyang Lake located in the downstream of each lake in every season. The relationship between the relationship between rivers and lakes and the different lakes and lakes in different ways and intensity of the difference is the main cause of the evolution of seasonal differences between the two lakes.