Numerical Simulation Of Interannual Variations Of Global Air-Sea Carbon Fluxes

The ocean is an important carbon sink in the global CO2. While the size of the sinks and their changes over time still there is a big debate. Atmospheric Sciences and global ocean carbon cycle model to explore the inter-annual variation of the air-sea carbon flux.In order to study the simulation capability of the ocean general circulation model LICOM (1.0) developed by the Institute of Atmospheric Physics, using CFC-11as a tracer and five different formulas of the air-sea gas transfer velocity, the global oceanic uptake of CFC-11is simulated from1944to2007under the forcing of climatological monthly mean data. The difference in gas transfer velocity derived from different formulas is discussed, and surface CFC-11concentrations, air-sea CFC-11fluxes, total water column inventory, cumulative uptake and vertical distributions are analyzed, respectively. The simulated results show that the air-sea gas transfer velocity of Wanninkhof (1992) formula is more suitable for the physical ocean model simulation of CFC-11. It is known from the relative difference in change of CFC-11uptake from different experiments that for a short time period (10years) from the beginning of the simulation, the sensitivity of CFC-11uptake to air-sea gas transfer velocity is greater, while during a long-term simulation, the oceanic uptake of tracers is probably more dependent on the physical model.With the use of biogeochemical processes coupled to the global ocean circulation model, and the air-sea gas transfer velocity formula of Wanninkhof (1992), before and after the industrial revolution the global ocean carbon cycle is simulated with the forcing of the NCEP interannually varying monthly mean atmospheric data. The model basically reproduces the observed distribution characteristics sea surface dissolved inorganic carbon and air-sea carbon flux during these two periods.Interannual variations of air-sea carbon fluxes are studied from1948to2009. Our model well reflects the interannual variations of sea surface temperature (SST), air-sea carbon flux, and so on. An analysis of the correlation between the air-sea flux and SST in the three different regions (equatorial region (14°S-14°N) and the southern and northern hemisphere regions) shows that ENSO events make a significant contribution to the global air-sea carbon fluxes, and interannual variations of the global air-sea carbon flux mainly depend on the equatorial region. Through the correction analysis between SST and the carbon flux in the6major regions of global oceans, it is obtained that the uptake of anthropogenic CO2in the equatorial Pacific region reveals an increasing trend, whereas the growth rate of the carbon flux in the Southern Ocean is gradually reduced, but still has not reached saturation. Finally, by the correlation analysis between the carbon flux anomaly in6major regions and the NIN03SST anomaly, it is known that the influence of the NIN03region on the global ocean is mainly reflected in the equatorial Pacific region, the North Pacific and Southern Ocean, and the impact on the equatorial Atlantic region, the North Atlantic and the Indian Ocean is small. Equatorial Pacific and North Pacific air-sea carbon fluxes have the highest correlation with SST, when the flux lags behind SST for about two months, while in the Southern Ocean the highest correlation occurs with8month lag.