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Impact of Prior Terrestrial Carbon Fluxes on Simulations of Atmospheric CO 2 Concentrations
Author(s) -
Fu Yu,
Liao Hong,
Tian XiangJun,
Gao Hao,
Jia Binghao,
Han Rui
Publication year - 2021
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2021jd034794
Subject(s) - environmental science , atmospheric sciences , carbon cycle , atmospheric carbon cycle , carbon fibers , carbon flux , terrestrial ecosystem , carbon dioxide , environmental chemistry , chemistry , materials science , geology , carbon sequestration , ecosystem , ecology , biology , organic chemistry , composite material , composite number
Terrestrial ecosystems have a significant role in shaping the distribution of atmospheric CO 2 , but it is uncertain how much they affect CO 2 concentrations. We assessed the impact of terrestrial fluxes derived from different biosphere models in the Multi‐scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP) on atmospheric CO 2 estimations based on a global chemical transport model (GEOS‐Chem) when these fluxes were applied as prior information. We examined the spatiotemporal uncertainty in terrestrial flux estimations from 15 MsTMIP terrestrial fluxes. We found high uncertainties in the terrestrial fluxes for temperate North America, tropical and temperate South America, southern Africa, Europe and tropical Asia. Sensitivity simulations showed that the annual mean CO 2 concentration changed by 6.0–8.0 ppmv with the spread of the terrestrial fluxes. The interannual trend in the terrestrial fluxes could significantly affect the simulated trend of atmospheric CO 2 concentrations. As a result of the spread in the prior terrestrial fluxes, large differences in the daily mean CO 2 anomalies changed with an interquartile range of −1.0 to +1.0 ppmv and the magnitude of change in the sub‐daily CO 2 concentrations was in the range 4.0–6.0 ppmv for China, the USA and Europe. Our results suggest an urgent need to increase the reliability of terrestrial flux estimates in CO 2 simulations. Surface seasonal CO 2 concentrations were simulated to change by ±2.0 ppmv in most regions of the world due to the differences in the ensemble mean fluxes, reflecting the impact of the uncertainties in the existing optimized terrestrial fluxes on CO 2 simulations.