[A-OS11] Ocean Mixing Frontiers

[AOS11-P02] Tracer distribution produced by an optimized physical field with an improved vertical mixing

*Toshimasa Doi¹, Shinya Kouketsu¹, Satoshi Osafune¹, Shuhei Masuda¹, Nozomi Sugiura¹ (1.Japan Agency for Marine-Earth Science and Technology)

Revealing the global oceanic tracer distribution is vital for climate research. To investigate how the circulation reproduced with the spatial changes in vertical mixing affects the biogeochemical cycles, in this study, the numerical experiment of advection/diffusion for chlorofluorocarbon (CFC) was conducted. An effect of spatial changes in vertical mixing was considered to an ocean general circulation model with near- and far-field vertical mixing schemes. The improved model was optimized with a four-dimensional variational data assimilation system, so that the temperature and salinity fields were consistent to a certain extent with the observations. It is known that the CFC is one of the anthropogenic substances, has no sink in the interior of the ocean, and the diffusion strongly influence on the transient behavior of CFC after being absorbed from the sea surface into the ocean. The time series of atmospheric CFCs concentration were given as the boundary condition of the model, and we show that transports by advection and diffusion of the absorbed CFCs in the ocean were calculated on the reanalysis circulation. Furthermore, we will discuss the effects of the spatial changes in the vertical field by comparing the result with the one with different vertical mixing schemes.