Global vegetation phenology data

We used the Normalized Difference Vegetation Index (NDVI) from the Terra MODIS MOD13C1 Version 6 product , which provides 16-day composite vegetation data at a 0.05° spatial resolution. The temporal coverage spans from 2001 to 2022. A Savitzky–Golay (S-G) filter was used to smooth noise and capture the overall seasonal curve. Then, an asymmetric Gaussian (A-G) function was used to fit the smoothed NDVI to get more accurately model phenological transitions. Spring and autumn phenological parameters (SOS and EOS)—were extracted using a dynamic threshold method (threshold = 0.5).