[A-CG35] Global Carbon Cycle Observation and Analysis

[ACG35-P05] Large influence of atmospheric vapor pressure deficit on ecosystem production efficiency

*Haibo Lu¹ (1.Beijing Normal University)

Keywords:Vapor Pressure Deficit, Drought, Gross Primary Production, Terrestrial Ecosystem

Disentangling the respective effects of soil moisture (SM) and vapor pressure deficit (VPD) on ecosystem production is challenging but essential for understanding terrestrial carbon uptake in response to dryness stress. In this study, by eliminating the coincident impacts of photosynthetically active radiation (PAR) and fraction of photosynthetically active radiation absorbed by plants (fPAR) on VPD and SM, using eddy covariance towers-based observations and global modeling data, we show that VPD rather than SM dominates ecosystem production efficiency over more flux sites and larger areas globally. Our analyses implicate that the impacts of VPD-induced atmospheric dryness on ecosystem production are at least equally, if not more important than SM, and the roles of VPD and SM should be fairly valued in ecosystem modeling.