归一化植被指数与降水量、土壤湿度的关系

归一化植被指数是描述植被绿度及生长状况的指数，由于植被生长依赖于环境条件因此ＮＤＶＩ与环境参量的关系是应用ＮＤＶＩ监测环境状况的基础。分别应用位于中国北部的干旱及半干旱地区的降水量资料对ＮＤＶＩ与降水量之间的关系地分析，结果表明仅在干旱半干旱地区生长季末的累积降水量与累积ＮＤＶＩ存在着显著的非线性关系，相关系数为０．７８。

The Relationship, between NDVI and Precipitation and Soil Moisture

The relationship between the normalitied difference vegetation index(NDVI)and precipita-tion is analysed, using the precipitation data in the arid and semi-arid region in the north of China. The result shows that the nonlinear relationship between cumulative NDVI (and maximumNDVI) by the end of growing season and the cumulative precipitation is significant. Its correlation coefficient is 0.78; In Huabei and Southwest China,the relationship between cumulative NDVI (and maximum NDVI) in the medium of growing season and the absolute moisture in 0-50cm soil layer is nonlinear. Its correlation coefficient is 0.60-0.65 (0.60-0.63).