Temporal and Spatial Changes of Vegetation Phenology and Their Response to Climate in the Yellow River Basin

Exploring the spatiotemporal variation in vegetation phenology in the Yellow River basin has significant scientific significance for ecological governance, protection, and construction in the region. In this study, the GOSIF and GOSIF_GPP remote sensing products from 2001 to 2020 were selected, and the double logistic curve fitting and dynamic threshold method were used to obtain three vegetation phenology parameters: start of season (SOS), end of season (EOS), and length of season (LOS) in the growing season of the Yellow River basin over 20 years. The results showed the following: (1) The vegetation phenology in the Yellow River basin exhibited an obvious zonal distribution pattern from east to west and from south to north. The SOS was mainly concentrated in March-April, and 33.83% of the regions showed a significant advance. The EOS mainly ended in October-November, 7.46% of the region showed a significant delay. The LOS was approximately 150–200 days, with 28.20% showing significant prolongation. (2) SOS showed a gradual delay from east to west and from south to north, while EOS showed a gradual advance from east to west and from south to north. (3) The correlation between SOS and temperature and precipitation is not strong, and the influence of temperature and precipitation on SOS is not strong; EOS is highly correlated with temperature (69.76%), but not with precipitation (94.39%). Temperature is the dominant factor in EOS variation. In conclusion, temperature is the main factor affecting the interannual phenological changes in the Yellow River Basin.