The measurement of atmospheric O2 concentrations and related oxygen budget have been used to estimate terrestrial and oceanic carbon uptake.However,a discrepancy remains in assessments of O2 exchange between ocean and atmosphere(i.e.air-sea O2 flux),which is one of the major contributors to uncertainties in the O2-based estimations of the carbon uptake.Here,we explore the variability of air-sea O2 flux with the use of outputs from Coupled Model Intercomparison Project phase 6(CMIP6).The simulated air-sea O2 flux exhibits an obvious warming-induced upward trend(～1.49 Tmol yr2)since the mid-1980s,accompanied by a strong decadal variability dominated by oceanic climate modes.We subsequently revise the O2-based carbon uptakes in response to this changing air-sea O2 flux.Our results show that,for the 1990-2000 period,the averaged net ocean and land sinks are 2.10±0.43 and 1.14±0.52 GtC yr-1 respectively,overall consistent with estimates derived by the Global Carbon Project(GCP).An enhanced carbon uptake is found in both land and ocean after year 2000,reflecting the modification of carbon cycle under human activities.Results derived from CMIP5 simulations also investigated in the study allow for comparisons from which we can see the vital importance of oxygen dataset on carbon uptake estimations.

Changyu LI;Jianping HUANG;Lei DING;Yu REN;Linli AN;Xiaoyue LIU;Jiping HUANG

College of Atmospheric Sciences,Lanzhou University,Lanzhou 730000,China;Collaborative Innovation Center for Western Ecological Safety,Lanzhou University,Lanzhou 730000,China;Enlightening Bioscience Research Center,Mississauga,L4X 2X7,Canada

大气科学进展（英文版）

[1]Changyu LI;Jianping HUANG;Lei DING;Yu REN;Linli AN;Xiaoyue LIU;Jiping HUANG-.The Variability of Air-sea O2 Flux in CMIP6:Implications for Estimating Terrestrial and Oceanic Carbon Sinks)[J].大气科学进展（英文版）,2022(08):1271-1284,中插5-中插7

Sinks,Tmol,yr2,GtC

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