|  |
Program |
 |
| |
 |
Special Session 6: The ocean’s energy cascade and mixing |
| |
|
|
Estimating turbulence properties in the seas surrounding Taiwan
SS6-02-S
Linan Weng* , Department of Oceanography, National Sun Yat-sen University
Presenter Email: wln2084050@gmail.com
|
| Abstract The turbulent mixing and dissipation processes play an important role in the maintenance and normal operation of the ocean circulation. In the coastal areas, complex terrains including continental shelves, slopes, and submarine canyons will enhance turbulence dissipation near the bottom. Therefore, it is reasonable to infer that turbulence properties and vertical diffusivities of the coastal regions are higher than those of the deep oceans. In this study, historical CTD data off southwestern Taiwan are analyzed by using Thorpe’s scaling method to estimate the dissipation rate of turbulent kinetic energy and vertical diffusion coefficient (Kz). The goal of this study is to compare the vertical averaged turbulence properties of various sites and to discuss the mechanism and process behind the differences. Our results indicate that the depth-averaged values of are 10-5~10-6 (W/Kg) in the Northern South China Sea (SCS). In the typical open ocean, the values of are about 10-7~10-8 (W/Kg). The reason of this difference could be the Kuroshio intrude into the SCS in winter and accelerates the speed of current to cause turbulences. Other reasons including internal waves or internal tides bringing greater energy dissipation to maintain the stability of the open oceans. Near the edge of the continent, the dissipation rate is about 10-3~10-4 W/kg in continental slope. The continental boundary has a complex topography, which changes the characteristics of the current while also increasing turbulence. In the Kuroshio area, the depth-average of is about 10-5~10-6 (W/kg). Compare with continental slopes the dissipation rate is relatively small. As this result, the main reason which controls the values of is different between southwestern and southeastern Taiwan due to that the Kuroshio effect in southwestern Taiwan is weaker than that in southeastern Taiwan. |
|
|
|
|