Landsat-5 TM图像分析洞庭湖区集成垸退田还湖前后植被量的变化

Application of Landsat-5 TM to analyze the change of vegetation quantity in Jicheng in the areas of “breaking dikes or opening sluice for waterstore” in Dongting Lake

目的 :探讨退田还湖前后集成垸试点植被量的变化 ,阐明退田还湖的影响 ,并提供方法学依据 .方法 :将集成垸试点依据NDVI值分类 ,以 10为组距分为 2 3组 ,将后 11组进行比较 .结果 :11类中有 6类退田还湖后NDVI值高于退田还湖前 ,占 5 4 .5 4 % ;其退田还湖前后面积分别占总面积的5 0 .36 %和 5 2 .30 % .结论 :Landsat 5TM图像可以较好地应用于退田还湖试点生态环境变化的研究 ;集成垸试点特定NDVI范围如 12 1～ 16 0 ,171～ 180 ,2 0 1～ 2 10段较退田还湖前增加 。

AIM: To study the change of vegetation quantity in Jicheng in the areas of “breaking dikes or opening sluice for waterstore” (BDOSW) in Dongting Lake and the effect of the policy on the prevention of. schistosomiasis. METHODS: The area of Jicheng, extracted from Landsat-5 TM images, was classified into 23 different categories based on different normalized difference vegetation index (NDVI) at the race of 10, and 11 categories were compared. RESULTS: NDVI of 6 out of the 11 categories after “BDOSW” was higher than that before “BDOSW” ( 54.54%). The areas of the 6 categories before “BDOSW” and after “BDOSW” accounted for 50.36% and 52.30% of the total area respectively. CONCLUSION: Remote sensing images of Landsat-5 TM can be applied to analyze the impact of the policy of “BDOSW” on ecological environment. Areas of some categories in Jicheng, for example, 121-160, 171-180 and 201-210 have increased after “BDOSW”, and the effect on the prevention of schistosomiasis needs further study.