Role of Eddies in Chlorofluorocarbon Transport in Wind-Driven Oceanic Layers

摘要

In this study the global distribution and transport of chlorofluorocarbons (CFCs) in the oceans are investigated using a high-resolution numerical model. The authors focus on the effects of wind-driven processes such as subduction and ventilation on the distribution of CFC-11 within surface and thermocline layers. Local maxima of tracer inventory are identified in oceanic regions. Two major absorption regions in the South Pacific Ocean are located west of South America and northeast of New Zealand in boundary latitudes between subtropical and subantarctic areas. In the North Pacific and south Indian Oceans, the positions of the local maxima of tracers migrate west-east with increasing density. The relationship between water formation and tracer distribution is discussed by comparing the wintertime mixed layer depth and mean circulation. The contributions of mean and eddy transport of the meridional overturning cells to tracer transport are analyzed. Stationary eddies have a large impact in the Southern Ocean, while transient eddies are crucial for the compensation of mean transport in the equatorial oceans. Mean and seasonal variability components of meridional tracer transport are dominant in the subtropics; however, eddy transport also plays a significant role.