The Influence of Topography on the Movement of Mesoscale Eddies along the Continental Slope of the New Zealand Plateau

This paper examines mesoscale eddies along the slope of the New Zealand Plateau. The study is based on altimetric measurements from 1993 to 2022: absolute dynamic topography and the META3.2 product. Additionally, data from the global oceanic reanalysis GLORYS12V1 for the same period are used. It is shown that a jet topographic flow is formed on the slope of the plateau, which runs along the slope of the New Zealand plateau in a narrow strip. The velocities of this topographic flow reach 70 cm/s when averaged over 1993–2022. It has been established that the generation of mesoscale eddies mainly occurs on the periphery of the topographic flow. Anticyclones are formed on the northern (shallow) periphery of the flow, and cyclones on the southern (deep-water). The section across the slope is considered and its parts where the flow velocity components normal to the section are maximal are determined. The trajectories of 1401 cyclones and 1488 anticyclones isolated from 1993–2022 with a life expectancy exceeding 10 days are analyzed. It is shown that the trajectories of cyclones and anticyclones are controlled by topography. In most cases, the trajectories of cyclones and anticyclones have a similar shape and are spaced apart.