Experimental Simulation of Upper Ocean's Vertical Dynamic Response to A Tropical Cyclone: pumping and mixing

The dynamic response of the ocean to a tropical cyclone in the vertical direction can be simplified into two processes theoretically: pumping and mixing. Based on the mechanism of these two responses, an index is defined to represent the relative strength between mixing and pumping (referred as RMP hereinafter). The larger RMP is, the stronger the mixing compared to the pumping is. In this paper, we took the variable-controlling approach to change the rotational speed and the immersion depth of the dynamic rotary plate, respectively. Then the vertical density profile before and after tropical cyclone was depicted to calculate index RMP. The trend of RMP after tropical cyclone shows that the attenuation of mixing is much slower than pumping at first. Besides, it turns out that RMP is negatively correlated with rotational speed (vorticity magnitude) and positively correlated with immersion depth, meaning that vorticity magnitude of tropical cyclone has a more powerful effect on pumping than mixing, while immersion depth has a more powerful effect on mixing than pumping. This experiment helps us attain a better understanding of the vertical dynamic response of the ocean to tropical cyclones. And the introduction of the index RMP helps provide a new idea for the quantitative research on the relative strength between mixing and pimping in the future.