近15 a秦岭林区水源涵养量变化特征

Spatiotemporal Variation of Water Conservation Capacity in the Qinling Mountain in Recent 15 Years

秦岭是陕西省乃至全国最主要的水源涵养区之一,也是"南水北调"中线工程的重要水源涵养区。研究秦岭地区水源涵养能力的空间分布,以及随时间的时空演化规律,对于寻找影响水源涵养能力变化的自然因素与人为因素都具有重要意义。在地表能量平衡原理和水均衡原理的基础上,利用2000—2014年降雨量和蒸发量数据对秦岭地区的水源涵养量进行定量评估,探讨近15 a来秦岭水源涵养量的时空演化特征,结果表明:在降雨量和陆地蒸散等多种因素的共同作用下,秦岭地区年水源涵养量在8.22~441.4 mm之间波动,整体呈现出波动增加的趋势,其中2011年最大,为441.4 mm,2002年最小,仅为8.22 mm;年水源涵养量安康市最高,宝鸡市最低;近15 a来,秦岭地区水源涵养能力的结构有所改善,<0 mm和0~300 mm所占比例呈下降趋势,占总面积的比例由84.48%下降至76.95%;300~600 mm和>600 mm所占比例呈现出波动上升的趋势,占总面积比例由15.52%上升至23.01%。秦岭地区年水源涵养量线性变化趋势以增加为主,增加的面积占总面积近9成,其中微弱增加占主导;增加最显著的地区主要集中在汉江中段。该研究结果可以为秦岭地区水资源保护提供科学的参考。

The Qinling Mountain is one of the most main headwaters in Shaanxi Province and even in China, and also the important headwaters for the south-to-north water transfer project. Research on water conservation capacity and its spatiotemporal variation in recent years in the Qinling Mountain was of important significance for revealing the effects of natural and human factors on the variation of water conservation capacity. In this study, the distribu- tion of water conservation capacity in the Qinling Mountain was evaluated based on the principles of water balance and surface energy balance. The spatiotemporal variation of water conservation capacity in the Qinling Mountain was explored using the meteorological data and land evapotranspiration of MODIS16 dataset during the period from 2000 to 2014. The results are as follows ：（1） Under the joint effects of various factors, such as rainfall and evapotranspira- tion ,the annual water conservation ranged from 8.22 to 441.4 mm in the Qinling Mountain,and water conservation was holistically in a fluctuated increase trend. The highest and lowest water conservation capacities were 441.40 mm in 2011 and only 8.22 mm in 2002 respectively; （2） In recent 15 years,the structure of water conservation in the Qinling district was improved. The area proportions of 〈 0 mm and 0 -300 mm were in a decrease trend and decreased from 84.48% to 76.95% ; those of 300 - 600 mm and 〉 600 mm were in an increase trend and in- creased from 15.52% to 23.01% ; （3） The linear variation trend of the annual water conservation in 97.97% area of the Qinling Mountain was dominated by increase, especially by slight increase. The areas with significant increase of the annual water conservation were mainly distributed in the Hanzhong reaches of the Hanjiang River.