[A-CG35] Projection and detection of global environmental change

[ACG35-09] Predictability of air-sea CO₂ fluxes with an Earth system model incorporating an initialization system

*Michio Watanabe¹, Hiroaki Tatebe¹, Hiroshi Koyama¹, Takahito Kataoka¹, Tomohiro Hajima¹, Masahiro Watanabe², Michio Kawamiya¹ (1.Japan Agency for Marine-Earth Science and Technology, 2.The University of Tokyo)

Keywords:Earth system model, Carbon cycle, Decadal prediction

Increased atmospheric CO₂ concentration causing global warming, which means the need for accurate prediction of variations in atmospheric CO₂ concentration is increasing. Uptake of CO₂ at the ocean and land surfaces is one of the fundamental processes in the global carbon cycle, and it is known to fluctuate in response to inherent climate variabilities such as the Interdecadal Pacific Oscillation (IPO) and the Atlantic multidecadal Variability (AMV). Therefore, predicting the changes in the carbon cycle associated with inherent climate change is essential for decadal-scale prediction of the carbon cycle. We are currently working on the decadal-scale prediction of the carbon cycle by incorporating an initialization system into an Earth system model that can represent the global carbon cycle. By comparing the results of the hindcast experiment with observations, it was found that the change in the CO₂ uptake by the ocean is predictable for about five years. Since the variations of air-sea CO₂ flux depends mainly on the variations of dissolved inorganic carbon concentration in the ocean, it is important to improve the prediction performance of the variations of dissolved inorganic carbon concentration in the ocean.