红崖山水库近20年面积变化遥感调查及驱动力分析

Remote sensing survey and driving force analysis of area change of Hongyashan Reservoir in the past twenty years

甘肃省红崖山水库位于水源缺乏的西北地区,是该地区生态系统的重要支撑,分析水库的面积变化便于当地政府统筹做好水生态保护修复,水资源合理利用,为其提供决策支持。通过对2000—2019年的Landsat系列数据和GF-2数据进行水域面积和植被覆盖度的提取分析,并结合周边气象数据和收集当地的资料综合分析水域面积变化的影响因素,探讨水域面积时空变化及驱动力。结果表明:总体特征上,2000—2019年20 a红崖山水库的水域面积持续增长,总面积增加8.98 km^(2),面积变化率高达42.6%;月际变化特征上,水域面积的变化呈现倒“正态分布”曲线趋势,丰水期主要集中在春秋季节的3月份和9—10月份,枯水期主要集中在夏季的6月份;年际变化特征上,由于水域面积受季节影响较大,故分春夏秋冬四季进行年际分析,春冬季节水域面积持续上升,平均年际增长率为5.03%和5.22%,秋季平均年际增长率最低仅为2.42%,夏季水域面积平均年际增长率为22.19%,是变化幅度最大的季节,呈“V”形波动上升。根据气温、降水和蒸发量等气象数据以及植被覆盖度与水域面积的相关性分析,以及相关水文资料分析,得出以下结论:直接驱动力是降水量的变化,工程扩建加高,入库径流变化;间接驱动力包括气温变化,植被覆盖度的变化,工、农、生活用水,生态环境修复等。

Hongyashan Reservoir is located in northwestern China where water resources are lacking.Reservoirs are an important support for the ecosystem in this region.Analyzing the changes in the area of the reservoir can effectively help Minqin County Government to make overall plans for water ecological protection and restoration as well as rational use of water resources and can also provide support for its decision-making.Through the extraction and analysis of the water area and vegetation coverage of the Landsat series data and GF-2 data from 2000 to 2019 and in combination with the surrounding meteorological data and the collection of local data,the authors comprehensively analyzed the influencing factors of the water area change and explored the spatial and temporal changes of the water area as well as the driving force.The results show that,on the whole,the water area of Hongyashan Reservoir has continued to increase in the past 20 years,the total area has increased by 8.98 km^(2),and the area change rate is as high as 42.6%,and that,in terms of monthly changes,the change in water area has an inverted“normal distribution”curve.The trend is that the wet season is mainly concentrated in March and September-October in the spring and autumn seasons,and the dry season is mainly concentrated in June in the summer.In terms of interannual variability,the water area is greatly affected by the seasons,so it is divided into spring,summer,autumn and winter.Interannual analysis shows that the water area in spring and winter continues to rise,with average annual growth rates of 5.03%and 5.22%,the lowest average annual growth rate in autumn is only 2.42%,and the average annual growth rate of summer water area is 22.19%,which is the season with the largest variation amplitude,exhibiting“V”fluctuation and rising.According to the meteorological data such as temperature,precipitation and evaporation,the correlation analysis of vegetation coverage and water area,and the analysis of related hydrological data,the following conclusions can be drawn:the direct driving forces are the change in precipitation,the increasing project expansion,and the change of runoff into the reservoir,whereas the indirect driving forces include changes in temperature,changes in vegetation coverage,the industrial,agricultural and domestic water use,and the restoration of the ecological environment.