【摘要】 以汶川地震干扰作用下岷江上游裸地变化特征为依据,选取岷江上游地形资料及2006年和2009年两个时期IRS-P6多光谱影像数据,通过对岷江上游地区裸地特征地类进行特征分析,在监督分类和聚类分析模块下提取出该区域裸地与非裸地范围,定量界定出岷江上游流域地震前后裸地变化范围。结果表明:岷江上游震前(2006年)裸地面积为2 196km2,震后(2009年)裸地面积为3 680km2,扩大了1 484km2;裸地分布高程从2 200m升高至2 800m,其面积增加较多区域主要集中在汶川县至茂县交界地带、理县的杂谷脑流域一带及黑水县部分区域,该区域亦是人口密度相对集中、地质灾害频发、生态环境相对薄弱的区域。该方法的实现为利用IRS-P6界定生境系统特征提供参考价值,也为环境脆弱性区综合评价分析提供技术支撑。更多还原

【Abstract】 On the basis of the bare land change characteristics in the upper reaches of the Minjiang River disturbed by Wenchuan earthquake, the topographic data and multi spectral image data in 2006 and 2009 are selected to be studied. According to analysis of bare land feature in the upper reaches of Minjiang River, the range of bare land and non-land in this area are extracted by supervised classification and clustering analysis module, and the range of variation of bare land in the upper reaches of Minjiang River before and after the earthquake are defined quantitatively. The study shows that: Bare land area is 2196km2 before the earthquake(2006) and is 3680km2 after the earthquake(2009), i.e. variation area increases 1484km2. Bare land elevation increases from 2200 m to 2800 m. The increased areas are mainly concentrated in the cross region between Wenchuan county and Maoxian county, Zagunao river basin in Lixian county, a part of Heishui county. These areas are also those with relatively high population density, serious geological disasters and relatively weak ecological environment. The realization of this method provides reference for the scientific definition of the regional environment system based on IRS-P6, and provides analysis support for comprehensive evaluation of fragile environment.更多还原