砒砂岩区坡面微地貌变化与侵蚀产沙的响应关系

为了定量描述坡面微地貌变化与侵蚀的响应关系,通过三维激光扫描仪,以严重侵蚀的砒砂岩区裸露坡面为研究对象,在自然降雨条件下进行野外原位监测,试验分析了两个雨季13次有效降雨下坡面微地貌与坡面侵蚀的空间变化特征。结果表明:(1)13次降雨中,重度侵蚀3次、中度侵蚀5次、轻度侵蚀3次、微度侵蚀2次,且均与降雨强度密切相关。(2)各地形因子均在R₄降雨时达到变化峰值,且其变化规律因坡位不同而有所差异,其中坡中与坡下变化规律基本一致,而上坡部地形因子波动起伏较为明显。(3)各地形因子间均存在一定的相关性,且坡位不同与产流产沙关系也不尽相同,其中产流量与微坡度相关性显著,随着坡位越靠下相关性越强。产沙量则在坡上及坡中与地表粗糙度表现为极显著相关,在下坡部与地表起伏度呈现出极显著相关。综上,坡面微地貌的变化一定程度上可以反映坡面侵蚀强度。

Responses of Slope Micro-geomorphology to Erosion and Sediment Yield in Arsenic Sandstone Area

In order to quantitatively describe the response relationship between slope micro-geomorphology change and erosion, based on the 3D laser scanner, this paper takes the exposed slope in the arsenic sandstone area which is severely eroded as the research object. The situ field monitoring was carried out under the condition of natural rainfall, the spatial variation characteristics of slope micro-topography and slope erosion were analysed under 13 effective rainfall in two rainy seasons. The results showed that:(1)There were 3 times more severe erosion, 5 times more moderate erosion, 3 times more light erosion and 2 times more slight erosion, and all of them were closely related to rainfall intensity.(2)All the topographic factors reached their peak values during R₄ rainfall, and the change rules varied with different slope positions. The change rules of the middle slope and the lower slope were basically the same, while the fluctuation of the topographic factors on the upper slope was more obvious.(3)There is a certain correlation among all the topographic factors, and different slope positions have different relationships with sediment yield, abortion and sediment yield. The correlation between runoff yield and gradient is significant, and the correlation is stronger with the lower slope position. The sediment yield was significantly correlated with surface roughness on the upper slope and on the middle slope, and with surface relief on the lower slope. To sum up, the change of slope micro-geomorphology can reflect the intensity of slope erosion to a certain extent.