Real and synthetic data used to test the Two-tracer Ratio-based Mixing Model (TRaMM)

This USGS Data Release represents the synthetic and real data from hydrologically diverse streams used to test the performance and limitations of the Two-tracer Ratio-based Mixing Model (TRaMM) which uses high-frequency measures of two tracers (A and B) and streamflow to separate total streamflow into water from slowflow and fastflow sources. The ratio between the concentrations of the two tracers is used to create a time-variable estimate of the concentration of each tracer in the fastflow end-member. Synthetic data from a groundwater dominated stream and an overland flow dominated stream were used to test the sensitivity of the model to various conditions and tracer concentrations. The sensitivity analysis provides understanding of the relation between the inputs and outputs of the model while providing information regarding its practicality and limitations. High-frequency nitrate and specific conductance data from Chesterville Branch, Maryland and Indian Creek, Kansas in 2013 were used to test the model under real-world conditions. These data support the following publication: Kronholm, S.C. and Capel, P.D., 2016, Estimation of time-variable fast flow path chemical concentrations for application in tracer-based hydrograph separation analyses: Water Resour. Res., 52, 6881-6896, https://doi.org/10.1002/2016WR018797.本美国地质调查局（United States Geological Survey, USGS）发布的数据集包含来自水文条件各异溪流的合成与实测数据，用于测试基于双示踪剂比值的混合模型（Two-tracer Ratio-based Mixing Model, TRaMM）的性能与局限性。该模型通过两种示踪剂（A、B）的高频监测数据与径流量数据，将总径流划分为慢速流与快速流两类水源。借助两种示踪剂的浓度比值，可估算快速流端元中每种示踪剂的时变浓度。研究团队使用以地下水补给为主与以地表径流补给为主的两类溪流的合成数据，测试模型对不同工况及示踪剂浓度的敏感性。本次敏感性分析既阐明了模型输入与输出间的关联，也揭示了模型的实用性与局限性。2013年取自马里兰州切斯特维尔支流（Chesterville Branch）与堪萨斯州印第安溪（Indian Creek）的高频硝酸盐及比电导率实测数据，用于在真实场景下验证该模型的表现。本数据集支撑如下已发表学术成果：Kronholm, S.C. 与 Capel, P.D. 于2016年发表于《水资源研究（Water Resources Research）》的《基于示踪剂的水文过程线分离分析中时变快速流路径化学浓度估算》一文（52卷，6881-6896页），原文链接：https://doi.org/10.1002/2016WR018797。