Abstract
The recurrent extreme El Niño events are commonly linked to reduced vegetation growth and the land carbon sink over many but discrete regions of the Northern Hemisphere(NH).However,we reported here a pervasive and continuous vegetation greening and no weakened land carbon sink in the maturation phase of the 2015/2016 El Nifio event over the NH(mainly in the extra-tropics),based on multiple evidences from remote sensing observations,global ecosystem model simulations and atmospheric CO2 inversions.We discovered a significant compensation effect of the enhanced vegetation growth in spring on subsequent summer/autumn vegetation growth that sustained vegetation greening and led to a slight increase in the land carbon sink over the spring and summer of 2015(average increases of 23.34％and 0.63％in net ecosystem exchange from two independent datasets relative to a 5-years average before the El Niño event,respectively)and spring of2016(6.82％),especially in the extra-tropics of the NH,where the water supply during the pre-growing-season(November of the previous year to March of the current year)had a positive anomaly.This seasonal compensation effect was much stronger than that in 1997 and 1998 and significantly alleviated the adverse impacts of the 2015/2016 El Niño event on vegetation growth during its maturation phase.The legacy effect of water supply during the pre-growing-season on subsequent vegetation growth lasted up to approximately six months.Our findings highlight the role of seasonal compensation effects on mediating the land carbon sink in response to episodic extreme El Niño events.
基金项目
National Key Research and Development Program of China(2022YFF0801802)
Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0306)
National Natural Science Foundation of China(42171050)
China Postdoctoral Science Foundation(2023M730281)
State Key Laboratory of Earth Surface Processes and Resource Ecology of Beijing Normal University(2023-KF-07)
维普
万方数据