2008年南方冰雪过程对生态环境影响的遥感监测--以湖南省资兴市为例

Remote Sensing Monitoring of Impacts of Southern Ice and Snow Process on Eco-environment in 2008:A Case Study in Zixing County,Hunan Province

2008年1月中下旬至2月上旬,我国南方地区出现了大范围、长时间的强降雪及冰冻灾害。这次冰冻雨雪灾害,不仅对广大人民群众的生活和社会经济运行造成了极大破坏,而且对当地生态环境也产生了深刻影响。本文以湖南省资兴市为例,运用遥感技术和地面野外调查相结合的方法,监测了本次冰雪过程对当地生态环境的影响。监测发现:本次冰雪过程对植被覆盖破坏显著,植被指数呈较大范围降低趋势,降低区域的总面积占资兴市土地总面积的54.12%;森林生态系统受损严重,除灌木林外302.2万亩森林全部受灾,其中,针叶林比阔叶林严重,幼龄林比成熟林严重,外来种比乡土树种严重,人工林比天然林严重;冰雪过程后土壤含水量增加、边坡失稳,地质灾害危险程度明显增高,工程建设区和林缘陡坡地带以滑坡(崩塌)为主的地质灾害频频发生。

A rare freezing rain and snow disaster attacked most parts of southern China from 15th January to 9th February, 2008. The extremely bad weather has not only destroyed people＇s daily life and production badly, but also influenced local eco-environment greatly. In this article, we monitored the impacts of southern ice and snow process on eco-environment with a case study at Zixing County in Hunan Province by making use of remote sensing and field survey methods. The results showed that the vegetation was destroyed badly and NDVI decreased for a large scale, and the decreased area of NDVI occupied 54. 12% of the total land area. The forest ecosystem was damaged badly. Except for some parts of shrub, all forest ecosystems were affected by disasters, which added up to 3.02 million hectare. It took on the following characteristics, coniferous trees were damaged more seriously than that of broad-leaves trees, young forests were damaged more seriously than mature forests, alien species were damaged more seriously than native species, planted forests were damaged more seriously than that of natural forests. On the other hand, the comprehensive risk degree of geological disasters increased, because soil water content increased and slope stability was weakened, which maybe induced geological disasters, such as landslides and collapses, occurring frequently in engineering construction regions and near edge of forests and steep-slope regions.