黄河流域主要植被类型NDVI变化规律及其与气象因子的关系

以黄河流域为研究区，通过分析流域内农作物、草地、林地、灌木4种植被类型的NDVI（归一化植被指数）在20世纪80年代初-90年代末的变化规律以及NDVI与降水、温度、API（可利用水指数）的相互关系，研究了流域内植被覆盖度的变化趋势及NDVI对气候因子的敏感性。结果表明，流域内植被覆盖度有增加趋势，生态环境向好的方向发展；6月农作物的NDVI与同期降水呈正相关，说明NDVI对该月的降水变化敏感，较多的降水有利于作物生长；7月降水与8月灌木、草地的NDVI呈显著正相关关系，说明它们之间具有滞后相关，两种植被类型8月NDVI对前一个月的降水量变化敏感；春季植被NDVI与同期温度的正相关关系说明春季NDVI对温度变化敏感，春季较高的温度有利用植被生长；春季NDVI与同期API的负相关关系说明春季温度对作物生长的影响较大。研究结果对进一步了解黄河流域不同植被类型NDVI变化规律及其对气候因子的敏感性具有一定意义。

Change of NDVI of Main Vegetations and Their Relationship with Meteorological Factors in Yellow River Basin

Changes of the Normalized Difference Vegetation Index(NDVI) of four main vegetations including crop,grass,forest and shrub in the Yellow River Basin and their relationship with the precipitation,temperature and Availability of Precipitation Index(API) were analyzed,by using NOAA and climate data from 1982 to 1999.The results showed that NDVI increased during 1982 to 1999 which indicated an improved ecological system.The NDVI in June was positively correlated to contemporaneous precipitation.There existed a positive lag correlation between precipitation in July and NDVI in August for crop and grass.The NDVI in August was sensitive to precipitation in the previous month.The NDVI was positively correlated to contemporaneous temperature,but negatively to contemporaneous API during spring,which indicated that higher temperature during spring benefited to plant growing.