Climate-warming-driven changes in the cryosphere and their impact on groundwater–surface-water interactions in the Heihe River basin
Climate-warming-driven changes in the cryosphere and their impact on groundwater–surface-water interactions in the Heihe River basin
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DOI：
10.5194/hess-27-2763-2023
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发表时间：
2023-07
影响因子：
6.3
通讯作者：
Amanda Triplett;L. Condon
中科院分区：
文献类型：
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作者：
Amanda Triplett;L. Condon
抽象的。中国西北部的黑河流域严重依赖人为和自然水库（例如地表水库、河流和地下水）来支持经济和环境功能。盆地上部的祁连山冰冻圈对于补充这些储存资源至关重要。众所周知，气候变暖正在通过冰川和永久冻土的消失推动高海拔水储存的重大变化。然而，对地下水-地表水-相互作用以及相应下游供水的影响尚不清楚。我们建立了中部流域的综合水文模型，这是用水量最大的地方，以探索冰冻圈变化的水文响应。我们通过改变模型的水流输入来表示冰冻圈融化过程，以及通过提高气候强迫数据的温度，模拟流域对冰川消失（冰川情景）、高级永久冻土退化（永久冻土情景）、这两种变化同时发生（组合情景）和预计中部盆地温度升高（变暖情景）的响应。冰川情景中地下水储存的净损失以及永久冻土和组合情景中的净收益显示了地下水交换调节水流变化的潜力。综合情景的结果还表明，永久冻土退化对系统的影响比冰川损失更大。地下水-地表水分配的季节差异也很明显。就早春的水流而言，冰川情景中地下水的比例最高。同时，永冻土和组合情景在春末和夏季的径流入渗比例最高。变暖情景使组合情景的温度升高 2 ∘C。这导致地下水储量净损失，与综合情况相反。相对于综合情景，蒸散量和河流网络连通性的巨大季节性变化表明变暖有可能压倒河流引起的变化。我们的结果证明了了解整个地下水-地表水交换系统对于评估气候条件变化下的水资源的重要性。最终，该分析可用于研究冰冻圈气候变化对全球山脉下游干旱盆地水资源恢复能力的连锁影响。
Abstract. The Heihe River basin in northwest China depends heavily on both anthropogenic and natural storage (e.g., surface reservoirs, rivers and groundwater) to support economic and environmental functions. The Qilian Mountain cryosphere in the upper basin is integral to recharging these storage supplies. It is well established that climate warming is driving major shifts in high-elevation water storage through loss of glaciers and permafrost. However, the impacts on groundwater–surface-water interactions and water supply in corresponding lower reaches are less clear. We built an integrated hydrologic model of the middle basin, where most water usage occurs, in order to explore the hydrologic response to the changing cryosphere. We simulate the watershed response to loss of glaciers (glacier scenario), advanced permafrost degradation (permafrost scenario), both of these changes simultaneously (combined scenario) and projected temperature increases in the middle basin (warming scenario) by altering streamflow inputs to the model to represent cryosphere-melting processes, as well as by increasing the temperature of the climate forcing data. Net losses to groundwater storage in the glacier scenario and net gains in the permafrost and combined scenarios show the potential of groundwater exchanges to mediate streamflow shifts. The result of the combined scenario also shows that permafrost degradation has more of an impact on the system than glacial loss. Seasonal differences in groundwater–surface-water partitioning are also evident. The glacier scenario has the highest fraction of groundwater in terms of streamflow in early spring. The permafrost and combined scenarios meanwhile have the highest fraction of streamflow infiltration in late spring and summer. The warming scenario raises the temperature of the combined scenario by 2 ∘C. This results in net groundwater storage loss, a reversal from the combined scenario. Large seasonal changes in evapotranspiration and stream network connectivity relative to the combined scenario show the potential for warming to overpower changes resulting from streamflow. Our results demonstrate the importance of understanding the entire system of groundwater–surface-water exchanges to assess water resources under changing climatic conditions. Ultimately, this analysis can be used to examine the cascading impact of climate change in the cryosphere on the resilience of water resources in arid basins downstream of mountain ranges globally.