中文摘要：

文中利用1999-2007年SPOT-VGT归一化植被指数,分析了天山北坡玛纳斯县NDVI的时空变化特征及其与主要气候因子（气温和降水）的相关关系。结果表明：（1）从年间变化看,1999-2007年间,玛纳斯县NDVI的多年平均值为0.17,总体上呈先下降后上升的趋势,表明玛纳斯县的生态环境有改善的趋势。从季节变化看,县平均NDVI年内季节变化明显,变化幅度在0.02~0.33之间,3月份开始上升较快,最高值出现在7月份。（2）从空间变化分布看,县域植被覆盖度均呈上升趋势,平原区和沙漠区的植被覆盖增加较大,可以看出县域在城镇绿化、基本农田保护、农田林网和防护林建设方面取得了较好的成效。（3）气温和降水是影响县域植被的重要气候因子,气温与月NDVI的线性相关系数为0.0071,降水与NDVI成指数相关,指数为0.1203。

英文摘要：

The spatio-temporal changes of vegetation coverage in Manasi county,Xinjiang province and their relationship with monthly temperature and precipitation were studied based on SPOT-VGT Normalized Different Vegetation Index data. The results showed that：（ 1） Annual NDVI presented a decreasing trend then steadily increasing trend during 1999-2007,suggesting the total ecological environment was improved in the county in the study period. The average annual NDVI was 0. 17 while the seasonal NDVI fluctuated between 0. 02 and 0. 33.The monthly NDVI maximum NDVI appeared in July and increased largely from March and reached the maximum value in July,then decreased more quickly from July to December.（ 2） The spatial distribution of NDVI had high association with water source area,altitude and vegetation form. From the spatial distribution of NDVI,flatlands and desert area showed a relatively high increasing trend than that in mountain area which suggested that Manasi county made progress in greening project,basic farmland protection,farmland shelterbelt construction and protection forest.（ 3） Temperature and precipitation were the main factors that affected NDVI. NDVI showed linear relationship with monthly temperature with the coefficient of 0. 0071,while showed exponent correlation with the precipitation with the index of 0. 1203.