Influencing factors of air-sea CO₂ exchange in the Western Tropical Pacific during the late Quaternary

Exploring air-sea CO₂ exchange helps to analyze the global carbon cycle and global climate change. Due to the direct contact between seawater and atmosphere, characterizing the changes in the carbonate system of surface water is the key to explore the air-sea CO₂ exchange. Available studies of the sea surface carbonate system in the Western Tropical Pacific (WTP) was reappraised, the principles, methods, advantages and disadvantages of reconstructing carbonate system parameters with foraminiferal B/Ca and δ¹¹B were summarized. Secondly, the research status of influencing factors of air-sea CO₂ exchange in the WTP during the late Quaternary was reviewed from three aspects: El Niño-Southern Oscillation (ENSO), East Asian monsoons, and atmospheric bridge and ocean tunnel. Results show that the ENSO-like processes can affect the air-sea CO₂ exchange in the eastern and western parts of the WTP via lateral advection and vertical change, respectively. The East Asian summer monsoon regulates the air-sea CO₂ exchange in WTP strongly and effectively, while the East Asian winter monsoon, weakly and insignificantly. During the deglaciation period, the increased ventilation of deep water in the Southern Ocean affects the air-sea CO₂ exchange in the WTP through the atmospheric bridge (atmospheric CO₂) and ocean tunnel (Antarctic Intermediate Water). In the future, more researches are required into the reliability and coverage of proxy records, and the mechanisms of air-sea CO₂ exchange over longer time scales, to understand changes in the global carbon cycle more accurately and clearly.