MODIS植被指数及其分县统计分析的实现

MODIS Vegetation Index and Its Calculation Method at County Level

MODIS归一化植被指数(NDVI)已引起了广泛的注意,它与NOAA/AVHRR的NDVI既有联系又有区别。利用同一天的NOAA/AVHRR和EOS/MODIS资料,介绍了各县域内平均NDVI的统计方法和计算结果及NDVI与增强植被指数(EVI)的差异。MODIS和AVHRR两种资料得到的NDVI数值虽然有差异,但都能很好地反映植被的空间分布和时间变化。MODIS增强植被指数(EVI)对植被条件的变化更加敏感,使定量分析的精确性提高,具有较好的应用前景。

MODIS Normalized Difference Vegetation Index （NDVI） has been widely noticed. It has relation with, but is different from NOAA/AVHRR NDVI. Using EOS/MODIS and NOAA/AVHRR data on the same day, the calculation of mean NDVI at county-level is conducted, and the computing method and the results are introduced. The application of the Enhanced Vegetation Index （EVI） in Shaanxi Province is discussed. Results of analysis show that although there is difference between MODIS NDVI and NOAA/AVHRR NDVI, they both can reflect the spatial distribution and the temporal variation of the vegetation. The MODIS EVI is more sensitive to the variation of vegetation conditions and can improve the precision of quantitative analysis, thus having good application potentials.