Spatiotemporal dynamics of the climatic impacts on greenup date in the Tibetan Plateau

摘要

Studying the response of vegetation phenology to climate change at different temporal and spatial scales is important for understanding and predicting future terrestrial ecosystem dynamics and the adaptation of ecosystems to global change. In this study, satellite-derived phenology metrics were used to explore spatial and temporal changes in climatic influences on the start of the vegetation green-up season (SOS) across the Tibetan Plateau during 1982-2012. The results showed that SOS changed to a greater degree in areas where the SOS started earlier. In areas where the spring temperature (T-spring) increased at a faster rate, SOS was more likely to be advanced, and the faster the T-spring increase the more obvious the advance of SOS was. The T-spring had a stronger impact on SOS in relatively moist eco-geographic regions, while spring precipitation (P-spring) had a stronger impact on SOS in relatively warm regions. The results also indicated that P-spring effect on SOS tend to get weaker from west to east, while T-spring effect on SOS would produce no significant variation along both altitude and latitude. The T-spring effect on SOS became gradually stronger from west to east, while the P-spring effect on SOS tended to become weaker. In addition, the thermal impacts on SOS became weaker from 1982 to 2012 which may attribute to the vegetation acclimation to environment changes.