Effects of Deep Bottom Topography on Dynamical Structure of the Kuroshio Extension

Effects of deep bottom topography on dynamical structure of the Kuroshio Extension are investigated by using an eddy resolving ocean general circulation model. The horizontal resolution of the model is about 10km around the Kuroshio Extension region. Results from experiments with different bottom topography are compared. For the first case, the bottom topography deeper than 5450m is not represented; ocean floor is flat at this depth. In the second case, deeper bottom topography in the Kuroshio Extension region up to about 7000m is represented. In this case, realistic distribution of eddy activities is obtained with its maximum value around 145°E-150°E. Potential energy in this region is also released realistically. For the first case, abyssal currents are not trapped by the bottom topography. On the other hand, in the second case, abyssal currents are trapped by the bottom topography and this results in larger shear between the upper and abyssal currents. This larger vertical shear of horizontal current may enhance release of potential energy and increase eddy activities.