A04-7 Dynamical analysis of diapycnal mixing processes in the ocean toward the formulation of their accurate parameterizations

   Research Summary

As grid resolutions in ocean general circulation models and coupled climate models become finer, the role of the sub-grid scale parameterizations becomes more important in controlling simulation results. Nevertheless, the existing diapycnal mixing parameterizations incorporated into these numerical models are not necessarily consistent with microstructure observations. In this research project, we plan to collect microstructure measurements from the ocean surface down to the ocean bottom using a vertical microstructure profiler (VMP-5500) equipped with a geo-electromagnetic current meter and a conductivity–temperature–depth (CTD) profiler and also using recently developed expendable microstructure profilers (XMPs). Furthermore, we perform large eddy simulations (LES) to illuminate the underlying physical mechanisms for the observed diapycnal mixing processes for the different ocean layers, surface, intermediate, deep, and bottom. Our goal is to identify the best performer of the existing turbulent mixing parameterizations for each of these layers and whether these parameterizations can be validated and/or improved. Our penultimate goal is to formulate a “seamless” parameterization of diapycnal mixing processes that can be applied throughout the water column, namely, from the ocean surface down to the ocean bottom.

   Member

Principle investigator : Toshiyuki Hibiya
(Professor, Graduate School of Science, The University of Tokyo)

Co-investigator : Yoshihiro Niwa
(Project Associate Professor, Graduate School of Science, The University of Tokyo)

Co-investigator : Yutaka Yoshikawa
(Associate Professor, Graduate School of Science, Kyoto University)

Co-investigator : Yuki Tanaka
(Research Associate, Graduate School of Science, The University of Tokyo)