通过综合运用气象数据、遥感数据和典型下垫面特征资料,采用GIS技术和SCS模型,分析了降水对洞庭湖湿地水文的补给效应。在分析洞庭湖流域降水时空变化特征以及模拟地表径流的基础上,计算面积补给系数和体积补给系数。结果表明,面积补给系数较好地显示出监测时刻湖泊水域面积与流域面积之间的关系,不仅反映了某一时刻湿地水文对补给水的依赖,也定量表明降水形成地表径流后的水文补给效应及其对水域面积的影响;体积补给系数则通过注入湿地中的实际水量反映出降水对湿地水文的补给作用及其对水文循环的贡献,也可通过累加反映一段时间内的补给效应。两者的综合应用可以更好地说明大气降水对洞庭湖湿地水文的补给作用。

Wetlands exist in a transition zone between aquatic and terrestrial environments which can be altered by subtle changes in hydrology. Hydrological process determines the formation, development and succession of wetlands. Taking the Dongting Lake as a study area, this paper studies the hydrological recharge effect of the atmosphere precipitation. According to the meteorological data, remote sensing image and typical underlay feature data, the recharge effectivity of the rainfall on the Dongting Lake wetland is analyzed supported by GIS (geographical information system) technology and SCS (Soil Conservation Service) model. Based on the analysis of spatio-temporal feature of rainfall and modeling of the runoff of precipitation, we obtained ARC (area recharge coefficient) and VRC (volume recharge coefficient). Thus, ARC well explains the acreage relationship of watershed and that of the water area in the lake sometime. It presents not only the wetland hydrology feature depending on the recharge water, but also the recharge effect of the runoff coming from rainfall and its influence on the water area. However, it is difficult to illustrate water fluid in wetland resulting from precipitation recharge in a period. Considering the relationship between flux of rainfall-runoff and volume of lake, VRC is calculated to make up for the shortcoming of ARC. According to the model, the recharge effectivity of rainfall can be computed in a certain period. ARC, together with VRC, can better explain runoff coming from rainfall as well as how it affects Dongting Lake's hydrological process and how it recharges water to the wetland, including the water area and water cycle. Thus it is significant to realize the importance of rainfall to the wetland and to protect and manage Dongting Lake wetland.