Model Study on Even Diffusion of CO_2 Released from 30 Ships in Mesoscale Deep Ocean

摘要

Among possible carbon capture and storage methods to mitigate the global warming, the direct injection of CO_2 into the deep ocean by the moving ship method, is considered to be a feasible way and expected to minimize its environmental impacts on marine organisms in the vicinity of the injection points. In this study, a simple but effective numerical model for the given practical scenario of very large system was developed with adopting moving and nesting grid technique and low-wavenumber forcing technique. The calculated results show that the maximum change of additional pCO_2 is lower than a non-observed effect concentration, +5,000 μatm, in the both small and mesoscale domains. This indicates that the scenario of 30 ships with different length of injection pipes injecting total CO_2 of 50 million t/yr and moving in the 111 km × 333 km operation area is efficient and effective. The developed techniques demonstrated its efficiencies and applicability to give an outline for the optimization of the CO_2 ocean sequestration system, by which biological impacts should be minimized and insignificant.