基于Landsat-8 OLI的岷县十里铺幅植被覆盖度多年变化与地质灾害时空分布关系

Relationship between Multi-year Change of Vegetation Coverage and Spatiotemporal Distribution of Geological Hazards on Shilipu Map in Minxian County Based on Landsat-8 OLI

以岷县十里铺标准图幅为研究区,基于Landsat-8 OLI(operational land imager)遥感影像数据分析1990—2018年的植被覆盖度多年动态变化特征以及发展趋势。将多年植被覆盖度与相近年份的地质灾害点进行空间叠加对比,分析植被覆盖度与地质灾害发生的时空对应关系,结合植被的水文效应以及力学效应探讨植被的抑灾及致灾作用机理。结果表明:研究区内植被先后经历急剧退化-逐渐恢复-略微退化的发展趋势,历年发生的地质灾害点主要分布于裸地和低植被覆盖度区域。地质灾害点分布密度总体随植被覆盖度的增加而减少,呈近似负相关关系。植被并不是决定地质灾害发育的关键因素,植被的水文效应和力学效应具有抑灾和致灾作用。在研判地质灾害发生概率时应综合考虑植被覆盖度、大气降水强度、历时产渗流等特征。

Taking the Shilipu standard map of Minxian County as the research area,based on Landsat-8 operational land imager(OLI) remote sensing image data,the dynamic changes and development trends of vegetation coverage over the years from 1990 to 2018 were analyzed.The spatial overlap comparison between vegetation coverage over the years and geological disaster points in similar years was conducted,and the spatiotemporal correspondence between vegetation coverage and geological disaster occurrence was analyzed,and the mechanism of vegetation disaster-suppression and disaster-causing was discussed by combining the hydrological and mechanical effects of vegetation.The results show that the vegetation in the study area has experienced the development trend of rapid degradation,gradual recovery,and slight degradation.The geological disaster points that have occurred over the years are mainly distributed in bare land and low vegetation coverage areas.The overall distribution density of geological hazard points decreases with the increase of vegetation coverage,showing an approximate negative correlation.Vegetation is not the key factor determining the development of geological disasters,and the hydrological and mechanical effects of vegetation have inhibitory and catastrophic effects.Vegetation coverage,atmospheric precipitation intensity,duration of seepage and other characteristics should be considered comprehensively when determining the probability of geological disasters.