基于MODIS—NDVI数据广西植被覆盖变化特征分析
2015-03-20喻素芳佘光辉罗叶红潘婷李丽娟
喻素芳+佘光辉+罗叶红+潘婷+李丽娟



摘要:利用月合成MODIS-NDVI时间序列数据、气象数据、DEM等数据,分析研究了2001-2010年广西省10年间植被覆盖变化的特征。结果表明,广西植被覆盖率较高且总体呈上升趋势,从区域角度分析,桂南地区增加趋势最显著,其次是桂中地区;从海拔梯度角度分析,海拔200 m以下的区域植被覆盖增加趋势最显著,但此区域的植被覆盖率较低,NDVI最高分布在海拔400~800 m的区域。植被覆盖变化受气温、降水及人类活动影响较大,植被覆盖梯度变化除受这些因素影响外,也与植被垂直地理分布特征相关。
关键词:MODIS-NDVI;植被覆盖;气温;显著
中图分类号:S812 文献标识码:A 文章编号:0439-8114(2015)02-0321-05
DOI:10.14088/j.cnki.issn0439-8114.2015.02.017
Analysis of Characteristics of Vegetation Cover Change in Guangxi Province Based on MODIS-NDVI
YU Su-fang1,2,SHE Guang-hui1,LUO Ye-hong2,PAN Ting2, LI Li-juan2
(1. School of Forest Resources and Environment ,Nanjing Forestry University ,Nanjing 210037, China;
2. School of Forestry,Guangxi University ,Nanning 530004, China)
Abstract: Base on the monthly time series MODIS-NDVI, meteorologic and digital elevation model(DEM) data from 2001 to 2010, analysed the change characters of surface vegetation coverage of Guangxi Province during this 10 years. The results showed that the vegetation coverage of Guangxi was at a high level with a growing tendency. The growing tendency was the most remarkable in southern Guangxi and followed by the middle Guangxi area. Vegetation coverage change with the vary classified elevation levels. The 200 m below level hold the most obvious growing trend while its NDVI was lower. NDVI was highest at altitude of 400~800 m range. The temperature, rainfall and human activities could influence the vegetation coverage. Beside all these three factors,the vegetation coverage was also associated with the vertical characteristics of geographical distribution of vegetation.
Key words: MODIS-NDVI; vegetation cover; temperature; obvious
地表植被的空间分布是植被对气候长期适应的结果,任何地区的植被均能反映出该地区的气候类型[1],并且植被覆盖状况能直接反映该地区生态环境状况,对全球环境变化具有指示器作用[2]。研究某一区域植被变化对研究该区域生态系统具有重要意义[3]。
植被指数(Vegetation Index)是指从多光谱遥感数据中提取的有关地球表面植被状况的定量数值,用以表征地表植被覆盖、生长状况和生物量等,常用的植被指数有:RVI、GVI、DDVI、PVI、EVI及NDVI等[4,5]。归一化植被指数(NDVI),又称标准化植被指数,是植物生长状态以及植被空间分布密度的最佳指示因子,与植被分布密度呈线性相关。同时,NDVI对土壤背景的变化较为敏感;与绿叶的叶面积系数(LAI)有很好的正相关性,可直接表征某地区的植被覆盖状况[3,5]。
一些学者基于不同的遥感……
