Lacustrine groundwater discharge (LGD) is of great importance to the hydrological cycle and the eco-environment of lakes. LGD is often characterized by large spatial variability, but the spatial patterns of LGD have rarely been quantified, particularly at large whole-lake scales. This study presents quantitative estimation of the spatial patterns of LGD in an oxbow lake in the central Yangtze River Basins by a segmented application of ²²²Rn mass balance model. The results show that the LGD rates in all points ranged from 10.05 to 197.25 mm/d, with an average of 61.23 mm/d. Larger LGD rates were not only occurring in the lakeshore area, but also in the lake center. The high LGD rate in the lake center area here was likely a result of a direct connection between the water-rich confined aquifer and the lake. Sensitivity analysis of the ²²²Rn mass balance show that lake water ²²²Rn concentration, groundwater concentration, wind speed and water depth were sensitive parameters, which were important parameters in controlling the quantitative results of LGD. The average LGD rate uncertainty and percentage were 28.45 mm/d and 49.20%. This study thus provides a solution in quantifying the spatial patterns of LGD lakes.

中文翻译：

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基于 222Rn 的湖泊地下水流量空间格局及定量分析

湖泊地下水排放（LGD）对湖泊水文循环和生态环境具有重要意义。LGD 通常以较大的空间变异性为特征，但很少对 LGD 的空间模式进行量化，特别是在大的全湖尺度上。本研究通过分段应用²²²Rn 质量平衡模型。结果表明，各点的LGD率在10.05~197.25 mm/d之间，平均为61.23 mm/d。较大的违约损失率不仅发生在湖岸地区，也发生在湖心。这里湖中心区的高 LGD 率可能是富水承压含水层与湖泊直接联系的结果。²²² Rn质量平衡敏感性分析表明，湖水²²² Rn浓度、地下水浓度、风速和水深是敏感参数，是控制LGD定量结果的重要参数。平均 LGD 率不确定性和百分比分别为 28.45 mm/d 和 49.20%。因此，本研究为量化 LGD 湖泊的空间模式提供了解决方案。