estimating the spatial heterogeneity of grassland productivity and carbon sequestration. In
this study, we first used satellite‐derived normalized difference vegetation index data and a
double logistic function to extract the start (SOS), end (EOS), and length of the growing
season in midlatitude grasslands of the Northern Hemisphere during 1981–2014. Then, we
verified the accuracy of satellite‐derived SOS and EOS using ground‐observed …