The Characteristic of The Two-Box Model Considering Plant Biota in Ocean under Unsteady-State Condition

Most ocean models so far proposed have taken only the inorganic carbon cycle into account. In our previous study, a model in which the carbon fixation by plant biota and the sedimentation of carbonaceous particles were considered was proposee. In the present study, an unsteady-state model is developed by improvement of the previous model incorporating gas exchange between the ocean surface and the atmosphere. The results are compared for the airborne fraction of CO2 from fossil fuel between the conventional two-box model and our model. Despite the expectations in the previous study, it was found that the amount of CO2 absorbed from the atmosphere into the ocean does not increase, as far as atmosphere-surface and surfacedeep sea exchange coefficients are determined from 14C distribution data. However, this model is physically sound as compared with conventional one. Furthermore, this model not only predicts airborne fraction variation but also estimates the validity of various techniques for solving CO2 problem.