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湖泊淹水范围的时空变化特征往往决定了湖泊湿地的景观结构和功能。鄱阳湖是我国最大淡水湖,水位和淹水范围的季节变化悬殊,鄱阳湖淹水特征对研究鄱阳湖湿地生态系统的结构与功能都具有显著意义,过去很多研究关注鄱阳湖水位-淹水面积关系,不同的研究者得到的水位-淹水面积关系各有差异,表现出一定的不确定性。利用多时相的卫星遥感影像提取的鄱阳湖水面面积的基础上,结合鄱阳湖长时间序列的水位观测资料,探讨鄱阳湖水位-淹水面积关系不确定的原因。研究结果表明:(1)尽管鄱阳湖水面面积与水位表现分段线性关系,但在相同水位条件下,鄱阳湖水面面积表现出较大的不确定性;(2)鄱阳湖水位表现南高北低的空间异质性格局,随着水位增加,鄱阳湖水位的空间异质性降低,并且水面坡降具有季相性,相同水位下退水期的水面坡降大于涨水期的水面坡降;(3)受洲滩地形和“堑秋湖”渔业方式的影响,相同水位下退水期出露洲滩中子湖泊的水面范围大于涨水期中子湖泊水面范围;(4)此外,鄱阳湖采砂显著改变采沙场的湖盆地形,从而改变低水位下的主要采沙场的淹水范围。综上所述,鄱阳湖水位-淹水面积关系的不确定性除了受湖盆地形、“五河”来水、长江顶托等自然原因,还有采砂和堑秋湖渔业方式等人类活动的原因。
The temporal and spatial variation of lake flooding range often determines the landscape structure and function of lake wetlands. Poyang Lake is the largest freshwater lake in China. The seasonal variation of water level and flooding range is significant. The characteristics of flooding in Poyang Lake have significant significance in studying the structure and function of the Poyang Lake wetland ecosystem. In the past, many researches focused on the Poyang Lake water level Relationship, different researchers have different levels of water level - flooding area, showing some uncertainty. On the basis of the surface area of Poyang Lake extracted from multi-temporal satellite remote sensing images and the long-time observation data of Poyang Lake, the paper discusses the reasons for the uncertainty of the relationship between the water level and the flooded area in Poyang Lake. The results show that: (1) Despite the piecewise linear relationship between the surface area of Poyang Lake and the water level, the surface area of Poyang Lake shows great uncertainty under the same water level; (2) With the increase of water level, the spatial heterogeneity of Poyang Lake water level decreased and the slope gradient of the water surface had the seasonal phase. The water surface gradient of the water level under the same water level was greater than that of the water level during the rising period. (3) Affected by the continental beach topography and the “Autumn Lake” fishing practices, the surface area of the neutron-lacustrine lake exposed at the same level of water level under the same water level is larger than the water level of the neutron lake at the period of water level rising. (4) In addition, Sand mining in Poyang Lake significantly changed the lake basin topography of the mining area so as to change the flooding range of the main mining area at low water level. In summary, the uncertainty of the relationship between water level and flooding area of Poyang Lake is affected by natural factors such as lake topography, incoming water from the “Wuhe River” and top watercourse of the Yangtze River, as well as sand harvesting and autumn fishing in the Qiuhu Lake Reasons for human activity.