Relations between AVHRR NDVI and ecoclimatic parameters in China

Based on monthly AVHRR NDVI data and weather records collected from 160 stations throughout China for 10 years, the relationships between NDVI and two ecoclimatic parameters ( growing degree-days (GDD) and rainfall) were analysed. The results indicate that a significant correlation exists between NDVI and the two ecoclimatic parameters; the NDVI/GDD correlation was stronger than the NDVI/rainfall correlation. The NDVI/rainfall correlation coefficient exhibits a clear structure in terms of spatial distribution. Further, the results indicate that for natural vegetation, the NDVI/rainfall correlation coefficient increases in order from evergreen forest, to deciduous forest, to shrubs and desert vegetation, to steppe and savanna. The correlation coefficients associated with cultural vegetation type depend on a number of factors including annual rainfall, seasonal variation in precipitation, type and intensity of irrigation practice and other environmental factors.