Analysis of relationships between NDVI and climatic/hydrological parameters in the Yellow River basin

NDVI is a key factor for describing variations of vegetation covers. In this research, NDVI values from 15 subregions and the main stream of the Yellow River basin during 1982-1998 were obtained and analysed. The results indicated that their peak values were observed in July or August annually. Annual mean values of NDVI increased across the basin except in the San-Hua and Upper-long subregions, implying that vegetation covers in most of the Yellow River basin were increasing over the 17 years. Moreover, significant positive correlations existed between NDVI values and climatic factors except a certain degree of time lags.