Role of turbulent mixing in the interior ocean on carbon uptake and biogeochemical cycle in the Pacific Ocean

Research summary

　It is believed that the global thermohaline circulation is strongly influenced by small-scale ocean mixing processes (diapycnal mixing). In addition, since carbon (dissolved inorganic carbon, DIC) and nitrate(nitrogen) rise to the surface layers associated with the deep water upwelling, the turbulent mixing processes can have a strong impact on biogeochemical cycles such as carbon and nitrogen, as well as the marine ecosystem. For climate studies, it is necessary to simulate water and biogeochemical cycles in the ocean, so that we need to embed the appropriate variations of diapycnal mixing coefficient into the atmosphere-ocean coupled general circulation models (AOGCMs) and Earth system models (ESMs).

　The turbulent mixing in the interior ocean is caused by wave breaking of an internal wave, that is created by tides and wind stress fluctuations. Previous studies have shown the strong spatial variations of diapycnal mixing coefficient in the real ocean. However, in the present model, the mixing coefficient is empirical and only depends on the depth. The role of the diapycnal mixing on the biogeochemical cycles has not well understood.

Fig.1 Components of the Earth System Model, MIROC-ESM (after Hajima et al., 2014).

Principal Investigator：
Michio Watanabe
Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
Project Team for Advanced Climate Modeling　Project Scientist

Collaborator：Tomohiro Hajima　Japan Agency for Marine-Earth Science and Technology (JAMSTEC)　Project Team for Advanced Climate Modeling　Research Scientist

Collaborator：Akitomo Yamamoto　Japan Agency for Marine-Earth Science and Technology (JAMSTEC) Project Scientist　Project Team for Advanced Climate Modeling　

Collaborator：Hiroaki Tatebe　Japan Agency for Marine-Earth Science and Technology (JAMSTEC) 　Project Team for Advanced Climate Modeling　Senior Research Scientist