利用遥感信息研究西藏地区主要植被年内和年际变化规律

利用1982～2000年NOAA-AVHRR月合成NDVI遥感资料和相关气象台站数据对我国西藏地区的稀疏草地、浓密草地和Tebit森林等主要植被的变化进行了初探。利用月合成NDVI的多年平均值分析了植被指数年内季节性变化规律及其与气候因子的关系，利用多年月合成NDVI的标准差描述了NDVI年际间波动情况。结果表明，在西藏地区，浓密草地和Tebit森林的NDVI植被指数年内变化规律呈明显的季节性，而稀疏草地则不明显；在年际变化方面，浓密草地月合成NDVI值波动幅度最大，Tebit森林次之，稀疏草地最小，且波动幅度较大的月份集中在NDVI值较高的植被生长季节6～10月份。

Intra-and inter-annual variation patterns of NDVI in Tibet based on AVHRR remote sensing data

Based on the NOAA-AVHRR and related meteorological data from 1982 to 2000,this paper studied the temporal variation of three main vegetation types(spare grass,dense grass and Tibet forest) NDVI(normal difference vegetation index) in Tibet.The intra-annual variation of NDVI and its connection with meteorological data were discussed,based on the average monthly composite NDVI estimated from AVHRR data,and the inter-annual variation of NDVI was analyzed by using the standard deviation of multi-years monthly composite NDVI.The results showed that dense grass and Tibet forest had an obvious seasonable variation of NDVI in a year,and spare grass had not.For the inter-annual dynamics of monthly composite NDVI,dense grass had the largest variation,followed by Tibet forest and spare grass.The months with relatively large inter-annual variation were mainly from June to October,the local main growth seasons with higher NDVI values.