气候变化背景下秦岭水源涵养功能时空变异特征

Temporal and Spatial Variation Characteristics of Water Conservation Function of Qinling Mountains Under the Background of Climate Change

水源涵养功能的变化对流域生态水文及其供水安全产生重要影响,稳定良好的水源涵养功能是区域经济社会高质量发展的基础。基于InVEST产水量模块、水源涵养模型、逐像元线性拟合,模拟1981—2015年秦岭及秦岭南北水源涵养时空变异,分析水源涵养对气候变化的响应,探讨气候波动背景下水源涵养演变趋势。结果表明:(1)近35年来秦岭水源涵养呈下降趋势,年变化速率-1.44 mm/a,秦岭北坡水源涵养下降趋势大于秦岭南坡;(2)近35年来秦岭水源涵养空间变化趋势呈空间异质性,除汉江南岸玉带河上游、牧马河上游、褚河上游年均水源涵养量略有增加外,其他流域呈整体下降趋势,且秦岭中部水源涵养下降幅度大于外围区域;(3)降水减少和参考蒸散发增加是影响秦岭水源涵养量减少的主要因素,在气候暖干化的背景下,秦岭水源涵养功能有进一步下降的可能。掌握区域水源涵养功能时空变异特征,对科学评估区域用水安全、预判未来水资源变化趋势和气候变化背景下水资源管理具有指导意义。

The change of water conservation function has an important impact on the ecological hydrology of the basin and the safety of water supply, A stable and good water conservation function is the foundation of the high-quality development of the regional economy and society. Based on the InVEST water yield module, the water conservation model and the pixel-by-pixel linear fitting, we simulated the temporal and spatial variation of water conservation in Qinling Mountains and the north and south slopes of Qinling Mountains from 1981 to 2015, analyzed the response of water conservation to climate change, and explored the evolution trend of water conservation under the background of climate fluctuation. The results show that:(1) The water conservation in Qinling Mountains showed a declining trend over the past 35 years, with an annual change rate of-1.44 mm, and the declining trend of water conservation on the northern slope of Qinling Mountains was greater than that on the southern slope of Qinling Mountains.(2) In recent 35 years, the trend of spatial changes in water conservation in Qinling Mountains had spatial heterogeneity, except for the upper reaches of the Yudai River, the upper reaches of the Muma River and the upper reaches of the Chu River on the suoth bank of the Han River, where the average annual water conservation increased slightly, the other river basins showed an overall downward trend, and the downward trend of water conservation in the central Qinling Mountains was greater than that in the peripheral regions.(3) Precipitation reduction and increased reference evapotranspiration were the main factors affecting the decrease of water conservation function in Qinling Mountains. Under the background of warm and dry climate, the water conservation of Qinling Mountains may further decline. Mastering the temporal and spatial variation characteristics of regional water conservation function has guiding significance for scientific assessment of regional water security, prediction of future water resources change trend and water resources management under the background of climate change.