| Seminar: | CPS Seminar |
| date: | 2026 September 1 (Tue) 15:30- |
| Room: | Z103, Building Z, Faculty & Graduate School of Science, Kobe University and Online (Hybrid meeting) |
| Speaker: | OKA Akira (Associate Professor, Atmosphere and Ocean Research Institute, University of Tokyo) |
| Title: | "How well can ocean mixing be inferred from temperature and salinity distributions? " |
| Abstract: |
In the ocean, heat and dissolved materials are transported not only by large-scale circulation but also by mixing, which plays an important role in shaping ocean circulation and climate. However, the intensity of ocean mixing varies greatly in space, and its global three-dimensional structure remains highly uncertain. How well, then, can the spatial structure of ocean mixing be inferred from observed temperature and salinity distributions?
In this study, we developed the Sea Tracer Adjoint calculatoR (STAR), an inverse analysis system based on the steady-state tracer advection–diffusion equation, and combined it with the ocean general circulation model COCO to address this question. We optimized vertical and isopycnal diffusivities to best reproduce the climatological distributions of temperature and salinity. Although the resulting local distributions retained some dependence on the initial conditions, a common large-scale spatial structure emerged that was relatively insensitive to the initial conditions. In this talk, after introducing the computational methods and presenting the results, we will discuss how well ocean tracer distributions, including temperature and salinity, can constrain the spatial structure of ocean mixing. |
| Keywords: | ocean mixing, ocean tracers, inverse estimation, adjoint method, vertical diffusivity, isopycnal diffusivity |
| Organizer: | George L. Hashimoto |