在植物生长周期内县级区域植被指数的时空演变特征分析

采用１９９１至１９９２年晴空时的ＮＯＡＡ卫星ＡＶＨＲＲ资料，计算甘肃省河东地区６０个县（市）作物和牧草生长周期内标准化差植被指数（ＮＤＶＩ）的平均值和标准差，并逐县绘制其时间演变曲线和直方图。选取以农作物、草地和森林草地混合为主的三类县作对比分析，研究县级区域植被指数时空变化与作物和牧草生育期的关系。分析１９９１至１９９２年度冬小麦生长周期内遇到严重干旱的情况，为干旱监测、估产和区分土地使用类型选择最佳时相提供依据

Analysis of the Space temporal Evolution Feature of Vegetation Index in County District Level During the Plant Growth Cycle

In this paper mean values of normalized difference vegetation index(NDVI) and their standard deviations in 60 counties or cities of the eastern Gansu province using the NOAA satellite AVHRR data selected the clear days during 1991～1992 have been calculated.Their temporal profiles and histograms of each county are drawn.Three types of county with major crop,grassland and forest mixed with grassland have been selected and comparatively analysed.The space temporal evolution of vegetation index in county destrict level related to the crop and pasture stage is studied.The status of the winter wheat growth cycle during 1991～1992 under serious drought condition is analyzed as a focal point.The results provide the basis of optimum phase and parameters for monitoring drought,crop yield estimation and land use classification.