The Influence Of Terrestrial Ecosystem Carbon Flux And Ocean Carbon Flux On The Global CO₂ Concentration Simulated By GEOS-Chem

The rate of atmospheric CO₂ increase in the atmosphere has exceeded the absorbed ability of nature,and it gradually affects global climatic warming.The use of model simulations has become an important tool to help us improve our understanding of the carbon cycle.We simulated CO₂ concentration by atmospheric chemical transport model GEOS-Chem driven by Biosphere Model SiB3 and optimized Carbon Tracker 2016terrestrial biospheric carbon fluxes for 2008-2010.We can deepen the understanding of the characteristics of the global terrestrial carbon source distribution and explore the impact of the carbon flux uncertainty on the simulation results to know the importance of improving carbon flux inversion accuracy in terrestrial ecosystem through the analysis the spatial distribution and seasonal variation of the simulated CO₂concentration.SiB3 and the optimized CT2016 terrestrial ecosystem carbon flux have obvious seasonal change,but they are opposite in Europe region and there is great uncertainty about the global total and spatial distribution.The simulation results show that the carbon flux of terrestrial ecosystem plays a leading role in the distribution of CO₂ concentration near the ground in human activities less areas,especially in the southern hemisphere and Europe,and the seasonal difference of the simulated results relies on the seasonal variation of the terrestrial biospheric carbon fluxes.The simulation results were compared with the data of 9 observation sites in order to select the suitable terrestrial ecosystem carbon flux to improve the accuracy of GEOS-Chem simulated CO₂ concentration.The experimental results indicate that two kinds of simulation results can simulate the peak and valley of seasonal change of CO₂concentration well,but the simulated CO₂ concentration using CT2016 closer to the observation data with higher simulation accuracy.This study also analyzed the distribution of the ocean carbon flux with interannual changes and compared it with the climatological ocean carbon flux to deepen our understanding of ocean carbon sources and sinks.To simulate global CO₂concentrations for the year 2008-2010,ocean carbon flux with interannual changes and the climatological ocean carbon flux were used to drive the GEOS-Chem model,an atmospheric chemical transport model.The simulated values were compared with the CO₂ concentrations at nine observation stations to explore the influence of interannual changes in the ocean carbon fluxes on the simulated CO₂ concentrations.We found that the difference between the two simulation results was greater in the Southern Hemisphere all year,and the difference in autumn was the largest.Compared with the observations,the simulated CO₂ concentration of the ocean carbon flux with interannual changes is closer to the observations,indicating that this simulation is more accurate.