摘要
沙地是半干旱区重要的地理单元,水流是传输沙地地表物质的主要动力之一。提取地表径流网络并定量估算地表水流对地表物质的输入和侵蚀作用,对于理解毛乌素沙地地表过程具有重要意义。本文利用10 m空间分辨率Sentinel-2卫星遥感影像和哥白尼数字高程模型(COPDEM),结合水体指数和河道烧录法自动提取了毛乌素沙地河流网络。利用降水、潜在蒸散发数据,基于Budyko模型,初步建立了半干旱区年均水蚀量估算方法,定量评估了毛乌素沙地地表物质年均水侵蚀量。结果表明,毛乌素沙地各流域河网密度最大的是佳芦河,其次为秃尾河和无定河,苦水河河网密度最小。在水力作用下,1992—2021年流入毛乌素沙地的泥沙量为0.07亿t/a,流出的泥沙量为0.45亿t/a,年均水侵蚀量为0.38亿t。解译遥感影像获得半干旱区河网分布、基于水文气象数据估算地表水蚀量,实现了半干旱区遥感图像解译—气候数据分析—径流量和地表水蚀量模型建立—地表水蚀定量评估的融合,为定量评估观测资料受限的半干旱地区地貌变化提供了新技术。
Sandy lands are important geographical units in semi-arid region in northern China,and runoff is one of the main transport forces of sediments in these areas.Extraction of river network and quantitative estimation of sediment input and output caused by surface water flows are of great significance for understanding the surface dynamic process and geomorphic evolution in the Mu Us sandy land of northern China.In this study,Sentinel-2 satellite remote sensing images with a 10-m spatial resolution and Copernicus Digital Elevation Model(COPDEM)were used to automatically extract the river network in exorheic regions of the study area by a combination of water index and stream burning method.Based on the Budyko model,a method for estimating annual average water loss in semi-arid region was established by using precipitation and potential evapotranspiration data.Then,the method was used to quantitatively evaluate annual water erosion of surface sediments in the Mu Us sandy land.Our results show that the Jialu River has the highest density of river network in the exorheic regions of Mu Us sandy land,followed by Tuwei River and Wuding River,and the Kushui River has the lowest density.Under erosion and deposition by runoff,the amount of sand materials transported into the Mu Us sandy land was about 7 million t/a,the amount of sand materials eroded out of the sandy land was about 45 million t/a from 1992 to 2021,and the average annual erosion by runoff was about 38 million t.Interpretation of remote sensing images helped to add more hydrological information to obtain river network in the semi-arid regions.Based on available hydrometeorological data,average annual water erosion in the semi-arid regions is estimated.The interpretation of remote sensing images,combined with climate data ananysis(potential precipitation-evaporation balance),runoff and surface erosion model,realized a quantitative assessment of surface water erosion in the semi-arid regions.This study provides a new apporach for quantitative assessment of geomor
作者
杨斐
鹿化煜
吴会娟
王菁菁
杨康
杨龙
李一泉
YANG Fei;LU Huayu;WU Huijuan;WANG Jingjing;YANG Kang;YANG Long;LI Yiquan(School of Geography and Ocean Science,Nanjing University,Nanjing 210023,China)
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
2024年第3期635-653,共19页
Acta Geographica Sinica
基金
国家自然科学基金项目(42021001,41920104005)。
