嘉陵江流域水文干旱特征及其驱动分析

Analysis of hydrological drought characteristics and drivers in Jialing River basin

  • 摘要: 嘉陵江是长江流域面积最大的支流,也是成渝双城经济圈高质量发展的重要“水动脉”,在全球气候变化和人类活动的双重叠加下,区域生态环境保护面临新的挑战.本文基于1990—2020年嘉陵江流域地表径流、降水、蒸散发和地下水水位等多源数据,应用标准化径流指数、游程理论、地理探测器和结构方程模型探讨嘉陵江流域水文干旱特征及驱动因子.结果表明:1)水文干旱随统计时间尺度延长呈现低频次、长历时、高烈度的演变规律,在短期、中期和长期时间尺度下均具有空间分布异质性特征.2)基于流域水文站点计算的不同时间尺度标准化径流指数具有明显的时空演变差异性,其中,2007年为流域水文干旱演变的重要突变节点.3)在过去30 a,地下水始终是水文干旱的首要正向调控因子,总效应由突变前的0.37衰减至0.23,蒸散发为第一负向调控因子,总效应减弱由突变前的−0.30变为−0.16;值得注意的是,突变节点后,耕地和建设用地的总效应均大于人类用水,因此土地利用变化引起的水文干旱加剧已逐渐取代人类用水成为重要驱动机制.本研究成果可为长江中上游水资源安全保障与干旱防控工作提供理论支撑.

     

    Abstract: Here is the revised academic English translation, updated according to your latest specification:The Jialing River is the largest tributary of the Yangtze River by drainage area and serves as a vital “water artery” for the high-quality development of the Chengdu-Chongqing economic circle. Under the superimposed pressures of global climate change and human activities, regional ecological and environmental protection is facing new challenges. Based on multi-source data including surface runoff, precipitation, evapotranspiration, and groundwater level in the Jialing River Basin from 1990 to 2020, this study applied the Standardized Runoff Index (SRI), run theory, Geodetector, and structural equation modeling (SEM) to investigate the characteristics and driving factors of hydrological drought in the basin. The results indicate the following: 1) As the statistical time scale lengthens, hydrological drought exhibits an evolution pattern of lower frequency, longer duration, and higher severity, with spatial heterogeneity consistently present across short-, medium-, and long-term scales. 2) The SRI series at different time scales, calculated from hydrological stations in the basin, displays pronounced spatiotemporal variability in its evolution, within which the year 2007 is identified as a critical turning point in hydrological drought development. 3) Over the past 30 years, groundwater has consistently been the primary positive regulating factor of hydrological drought, with its total effect declining from 0.37 before the turning point to 0.23 after. Evapotranspiration acts as the primary negative regulating factor, and its total effect weakened from −0.30 before the turning point to −0.16 after. Notably, after the turning point, the total effects of both cropland and built-up land exceeded that of human water use, indicating that the intensification of hydrological drought driven by land use change has gradually replaced direct human water use as a significant driving mechanism. These findings can provide theoretical support for water resources security and drought prevention and control in the upper and middle reaches of the Yangtze River.

     

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