Key Laboratory of Remote Sensing of Gansu Province, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
Ministry of Education Key Laboratory of Virtual Geographic Environment, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing 210023, China.
Sci Total Environ. 2018 May 1;622-623:1016-1028. doi: 10.1016/j.scitotenv.2017.12.055. Epub 2017 Dec 13.
Separating impacts of land use/land cover change (LUCC) and climate change on hydrology is essential for watershed planning and management. This is typically done via hydrological modelling in combination with the one-factor-at-a-time analysis. However, it remains unclear how large the differences in isolated hydrological impacts would be when selecting different baseline periods. In this study, we compared baseline period choices for separating climate change and LUCC impacts on watershed hydrology in a typical inland river basin in northwest China, i.e. the Upper Heihe River Basin, with two hydrological models, i.e., Soil and Water Assessment Tool and Distributed Hydrology Soil Vegetation Model. In the real LUCC case which considers the actual land use changes between 2000 and 2011, the absolute contributions of LUCC to the variations in water yield and ET are slight and almost have the same magnitude for different baseline period choices, whereas those of climate change are substantial and with varying magnitudes. Compared with the absolute contributions, the relative contributions of climate change and LUCC seem less sensitive to the choices of baseline periods. In the hypothetical LUCC case which assumes an extreme land use conversion (i.e., grassland converts to farmland completely), both climate change and LUCC contribute to the changes in water yield and ET significantly. Moreover, both the absolute and relative contributions diverge noticeably between various baseline period choices. The influences of baseline period choices on the partitioning of hydrological impacts diverge significantly between different hydrological models. This study highlights that baseline period choice is an important source of uncertainty when disentangling the impacts of LUCC and climate change on hydrology. Some useful recommendations regarding baseline period selection have been proposed, which may help to reduce the uncertainties associated with baseline period choices.
分离土地利用/土地覆被变化（LUCC）和气候变化对水文的影响对于流域规划和管理至关重要。这通常通过水文模型与逐个因素分析相结合来完成。然而，当选择不同的基准期时，孤立的水文影响差异有多大仍不清楚。在这项研究中，我们比较了两种水文模型，即土壤和水评估工具和分布式水文土壤植被模型，用于分离中国西北内陆河流域即黑河上游流域气候变化和 LUCC 对流域水文影响的基准期选择。在实际的 LUCC 情况下，考虑了 2000 年至 2011 年之间的实际土地利用变化，LUCC 对产水量和蒸散量变化的绝对贡献很小，并且对于不同的基准期选择几乎具有相同的幅度，而气候变化的贡献则很大，幅度不同。与绝对贡献相比，气候变化和 LUCC 的相对贡献似乎对基准期选择的敏感性较低。在假设的 LUCC 情况下，假设草地完全转化为农田，气候变化和 LUCC 都会显著导致产水量和蒸散量的变化。此外，各种基准期选择之间的绝对和相对贡献差异明显。基准期选择对水文影响划分的影响在不同的水文模型之间差异很大。本研究强调，当分离 LUCC 和气候变化对水文的影响时，基准期选择是不确定性的一个重要来源。提出了一些关于基准期选择的有用建议，这可能有助于减少与基准期选择相关的不确定性。
