Global Mapping of Mesoscale Eddy Vertical Tilt
Hong Li, Fanghua Xu, Guihua Wang
Abstract
Abstract Vertical motion induced by oceanic mesoscale eddies can strengthen ocean ventilation, and regulate vertical distribution of heat, dissolved CO 2 and other tracers on a global scale. Eddy‐induced vertical motion is closely related to eddy vertical structure. Here, based on available satellite observations and Argo profiles, we find that mesoscale eddies in global oceans are prevalently vertical tilted. Anticyclonic eddies are frequently tilted westward and poleward from 300 dbar up to sea surface, while cyclonic eddies are frequently tilted westward and equatorward. The horizontal tilting distance of eddies is significantly correlated ( r ≥ 0.84) with the Burger number (the ratio of vertical stratification to planetary rotation and eddy size), indicating a strong constraint of Earth's rotation and ocean stratification on eddy vertical tilt. On average, the maximum vertical velocity in tilted circular eddies is at least one order of magnitude larger than that in non‐tilted circular eddies. This finding would improve estimates of eddy‐induced vertical motion, ventilation, so as to heat/salt and biogeochemical responses.