桂林岩溶峰丛区定域时空变化研究

为探索局域生态环境变化对桂林市整体生态环境状态的影响,选择漓江沿岸北从刘村南至街底共8个峰丛地貌区作为研究对象(编号为No.1~No.8),并以1986、1991和2006年3个时相的Landsat-5卫星影像的TM数据为信息源,采用基于ROI的定域定量遥感技术,结合地理与岩溶地质学资料,对这8个岩溶峰丛区的遥感生境指标即归一化植被指数NDVI和缨帽变换中的绿度分量TC2作定域提取和纵、横向分析(时间和空间变化分析)。研究表明,2006年岩溶峰丛区的NDVI和TC2最高,生态环境最好,1986年次之,1991年最差,表明在20世纪80年代末90年代初这一阶段里,由于桂林市经济高速发展而忽视环保,岩溶峰丛区的生境曾受到较不良影响,但进入本世纪以来已经得到了明显改善;在空间上各峰丛区NDVI大于4.0和TC2大于20的地块呈现斑状或条带状分布,且自1991年以来有向全区扩大的趋势。同一区域不同时间NDVI和TC2变化具有1991年低,1986年、2006年高的趋势,而同一时间不同区域NDVI和TC2也存在着差异,由好到差其关系为:No.5>No.4>No.3>No.8>No.7>No.6>No.2>No.1。 

Study on localization of temporal and spatial variation in karst peak cluster in Guilin

In order to discuss the impact of local eco-environment changes on the entire eco-environment in Guilin, 8 zones of peak-cluster are selected as the study object from Liucunnan to Jiedi along the north bank of the Lijiang River（No. l~No. 8）, localization extraction and temporal and spatial variation analysis have been done for the RS habitat index, NDVI and the greenness component （ TC 2） of Tasseled Cap in the se- lected 8 zones by means of localized and quantitative RS in region of interest （R（）I） technique with the data come from TM of Landsat-5 in 1986, 1991 and 2006 and other geology and geography information. The re- sults show that,the NDVI and TC2 indexes at the peak-clusters are the highest in 2006 and the eco-environ- ment is the best; it takes second place in 1986 and worst in 1991 proving the habitat is blighted due to the ig- noring of environmental protection during economic develops rapidly in Guilin at the end of the 1980＇s and the beginning of 1990~s in the 20th century, however, it is improved obviously in the 21st century with some patches or bands assuming high eco-environment rank showed by NDVI and T（＇e （i. e. NDVI index~0.4 and TCz index20） , which tends to enlarging to the whole area from 1991. The values of NDVI and TC 2 are of the tendency-low in 1991 and high in 1986 and 2006 in the same region hut different time, and there is also difference in NDWI and TC2 value at the same time but different region. From good to bad relationships, the arrangement is,No. 5〉No. 4〉No. 3〉No. 8〉No. 7〉No. 6〉No. 2〉No. 1.