摘要
广西西江流域作为我国西南地区重要的水源涵养区,也是生态环境敏感脆弱的区域,对这一区域的植被覆盖进行检测和分析具有重要意义。文章基于2000-2016年分辨率为250米的MODIS-NDVI数据,采用Theil-Sen Median趋势分析法和Mann-Kendall检验,研究了广西西江流域NDVI时空变化特征和变化趋势,结果表明:(1)广西西江流域总体植被覆盖度较高,高植被覆盖区域主要分布在流域东部和西北部,中低值区域主要分布在流域中南部,形成了四周较高植被覆盖度,中间较低植被覆盖空间分布特征。(2)2000-2016年广西西江流域植被覆盖呈缓慢增加的趋势,植被覆盖明显改善的区域主要分布在流域中部,植被覆盖明显退化的地区主要位于南宁市、贵港市的浔郁谷地平原地区、百色市的右江谷地地区。(3)不同的土地利用类型中,建设用地、耕地中植被覆盖显著退化的比例最高,草地、林地的植被覆盖改善比例最高,同时具有随高程、坡度等级的增加植被覆盖呈退化趋势比例减少的特点。
As an important water conservation area in southwestern China,the Xijiang River Basin in Guangxi is also a sensitive and fragile area of ecological environment.It is of great significance to detect and analyze the vegetation cover in this area.Based on the MODIS-NDVI data with a resolution of 250 meters from 2000 to 2016,the Theil-Sen Median trend analysis method and the Mann-Kendall test are used to study the temporal and spatial variation characteristics and trends of NDVI in the Xijiang River Basin in Guangxi.The results show that:(1)The overall vegetation coverage of the Xijiang River Basin in Guangxi is relatively high.The areas with high vegetation coverage are mainly distributed in the east and northwest of the basin,while the areas with middle and low vegetation coverage are mainly distributed in the south and central of the basin,forming the characteristics of high vegetation coverage around and low vegetation coverage in the middle.(2)From 2000 to 2016,the vegetation cover in the Xijiang River Basin in Guangxi showed a slow increase trend.The areas with obvious improvement of vegetation cover were mainly distributed in the middle of the river basin,the areas with obvious degradation of vegetation cover were mainly located in the plains of Nanning City and Guigang City,and the Youjiang Valley area of Baise City.(3)Among different types of land utilzlation,the proportion of vegetation coverage in construction land and cultivated land is the highest,and the proportion of vegetation cover improvement in grassland and forest land is the highest.At the same time,the proportion of vegetation cover is degraded with the increase of elevation and grade of slope.
出处
《大众科技》
2019年第10期28-31,共4页
Popular Science & Technology
