Assessing The Impacts Of Extreme Climate Events On Vegetation Activity In The North South Transect Of Eastern China(nstec)

Extreme climate events frequently exert serious effects on terrestrial vegetation activity.However,these effects are still uncertain in widely distributed areas with different climate zones.Transect analysis is important to understand how terrestrial vegetation responds to climate change,especially extreme climate events,by substituting space for time.The North South Transect of Eastern China(NSTEC)accounts for nearly1/3 of China's land area and has many agroforestry ecosystems,which can almost represent China's terrestrial ecosystem.NSTEC is also a typical heat driven series of latitudes in the world,providing an excellent natural test platform for climate ecosystem research.In this paper,seven extreme climate indices and the Normalized Difference Vegetation Index(NDVI)and the Solar-induced Chlorophyll Fluorescence(SIF)data are employed to examine changes in the extreme climate events and vegetation activity.The NDVI datasets,encompassing the MODIS NDVI dataset(MOD13Q1)and synthetic dataset Sun-Induced Chlorophyll Fluorescence driving from MODIS were employed to capture changes in vegetation activity.The impacts of climate extremes on vegetation activity were then assessed over the period of 2000 ? 2018.The results show that vegetation activity was overall strengthened from 2000 to 2018 in the NSTEC.In addition,extreme high temperature events revealed an increased trend of approximately 0.15 ± 0.0.5 ? days per year since 2009,while a weakened trend(not significant)was found in extreme cold temperature events.Extreme high temperature events revealed an increased trend of approximately 19 ± 8.9 mm per decade.The strengthened vegetation activities could be associated with enhanced extreme high temperature events and weakened extreme cold temperature events over the past decades in most of the NSTEC.Despite this,inversed changes were also found locally between vegetation activity and extreme climate events(e.g.,in the Northeast Plain).These phenomena could be associated with differences in vegetation type,human activity,as well as the combined effects of the frequency and intensity of extreme climate events.This study highlights the importance of accounting for the vital roles of extreme climate effects on vegetation activity.