the 22nd Pacific−Asian Marginal Seas meeting (PAMS)

Mesoscale eddies, prevalent across the global ocean, play a crucial role in the horizontal and vertical transport of climate-sensitive tracers such as heat, salt, and nutrients. While traditional quasi-geostrophic theory predicts symmetric kinematics and thus equivalent material transport by cyclonic and anticyclonic eddies, our analysis of satellite altimeter and surface drifter data shows that cyclonic eddies capture about 12.5% more drifters than anticyclonic eddies globally. Numerical model experiments reveal that this asymmetry results from eddy-wind interactions, which induce Ekman downwelling (convergence) in cyclones and Ekman upwelling (divergence) in anticyclones, leading to enhanced particle aggregation in cyclonic eddies. Using satellite and Argo observations, we further show that both cyclonic and anticyclonic eddies drive a net upward heat transport across the global ocean, with a time-mean maximum of 40 W m^-2 along the western boundary currents. This vertical heat transport peaks at eddy centers, scales positively with eddy amplitude, and exhibits a significant seasonal cycle that is coherent with the seasonal variability of Ekman pumping. These findings provide important new insights into the distribution and transport of materials within ocean eddies, as well as the role these eddies play in Earth’s climate.

Mesoscale eddies,Particle aggregation,Eddy trapping,Vertical heat transport