As China's Loess Plateau has lately witnessed increasingly extreme precipitation events,it is important to analyze the impact of extreme precipitation and identify the conditions for the occurrence of geological d...As China's Loess Plateau has lately witnessed increasingly extreme precipitation events,it is important to analyze the impact of extreme precipitation and identify the conditions for the occurrence of geological disasters.Field surveys can provide detailed geological information in this regard but are time consuming and labor intensive.In this paper,we provide a case study on the Gutun catchment of Yan'an,which was affected by prolonged heavy rainfall in July 2013.We used Digital Elevation Model(DEM)data obtained by processing ZY-03 stereo-pair images before and after the rainy season,including the period of prolonged heavy rainfall mentioned above,to analyze the topographical changes triggered by the rainfall.The results showed the following:(1)The rainy season reduced the elevation of the catchment by about 1.7 cm.The major change in its elevation ranged from-0.5 to 0 m,accounting for 38.41%of the overall area of change and dominating above 70 m of slope height.(2)The rainy season increased the average inclination of the slopes in the area from 28.81°to 28.95°,while the range of their peak inclination was mainly distributed in the range of 24°-36°.(3)Sunny and half-sunny slopes exhibited a greater loss in elevation,while shady and half-shady slopes exhibited an increase in elevation.More drastic topographical changes were observed in the shady and half-shady slopes.(4)The morphology of the area that had undergone a reduction in elevation was characterized by concave slopes,while convex slopes abounded in the area with increased elevation.(5)The sunny or shady properties of the slope aspect constituted the key factor influencing the topographical changes,followed by the height,inclination,and shape of the slopes.The work here can provide guidance for measures related to disaster prevention and mitigation.展开更多
基金National Natural Science Foundation of China,No.42271279,No.41931293,No.41801175Taishan Industrial Experts Program。
文摘As China's Loess Plateau has lately witnessed increasingly extreme precipitation events,it is important to analyze the impact of extreme precipitation and identify the conditions for the occurrence of geological disasters.Field surveys can provide detailed geological information in this regard but are time consuming and labor intensive.In this paper,we provide a case study on the Gutun catchment of Yan'an,which was affected by prolonged heavy rainfall in July 2013.We used Digital Elevation Model(DEM)data obtained by processing ZY-03 stereo-pair images before and after the rainy season,including the period of prolonged heavy rainfall mentioned above,to analyze the topographical changes triggered by the rainfall.The results showed the following:(1)The rainy season reduced the elevation of the catchment by about 1.7 cm.The major change in its elevation ranged from-0.5 to 0 m,accounting for 38.41%of the overall area of change and dominating above 70 m of slope height.(2)The rainy season increased the average inclination of the slopes in the area from 28.81°to 28.95°,while the range of their peak inclination was mainly distributed in the range of 24°-36°.(3)Sunny and half-sunny slopes exhibited a greater loss in elevation,while shady and half-shady slopes exhibited an increase in elevation.More drastic topographical changes were observed in the shady and half-shady slopes.(4)The morphology of the area that had undergone a reduction in elevation was characterized by concave slopes,while convex slopes abounded in the area with increased elevation.(5)The sunny or shady properties of the slope aspect constituted the key factor influencing the topographical changes,followed by the height,inclination,and shape of the slopes.The work here can provide guidance for measures related to disaster prevention and mitigation.
