Regional-scale vegetation-climate interactions on the Qinghai-Tibet Plateau

Response and feedback of vegetation growth to climate change are a series biogeophysical processes from local to regional scales. Revealing the vegetation-climate interaction is fundamental to understand the evolution of earth surface system in the context of global climate change. Due to the low temperature and vulnerable biotic and abiotic settings, the alpine ecosystems are sensitive to climate change, peculiarly in the Qinghai-Tibet Plateau (QTP). By combining the climate factors (precipitation and temperature) and vegetation state indicated by the Enhanced Vegetation Index (EVI) data we try to reveal the pertinent temporal reaction mode of vegetation to climate change on the QTP. The vegetation-climate interactions were investigated by using the Granger causality test technique. The prime findings of this study are: (1) vegetation showed a strong sensitivity to warmingwetting climate in most arid and semi-arid areas of the QTP; (2) the reaction patterns of EVI to precipitation show a temporal lag of 0-1 months, which was strongest to the cumulative precipitation within 1-2 months; (3) The time lag effect and cumulative effect of temperature on vegetation both occurred within 1 to 2 months; (4) The unidirectional Granger causes of precipitation and temperature to vegetation accounted for 17.65% and 8.66% of the entire QTP, respectively. This study emphasizes a sensitive response of the vegetation to climate change (precipitation and temperature) in the QTP. Vegetation feedback makes the fluctuations and effects of climate more complicated. The results indicated that more insights into the future forecasting of climate change and vegetation dynamics can be acquired by a specific and comprehensive analysis of vegetation-climate coupled feedback.