Title: Effect of Mesoscale Oceanic Eddies on Extratropical Cyclogenesis: a Tracking Approach

Journal: Journal of Geophysical Research: Atmospheres, doi: 10.1029/2019JD030595

Authors: ZHANG X. -Z., X. -H. Ma*, and L. -X. Wu

Abstract: Oceanic eddies populated in the western boundary current regions in the midlatitude have been found to exert significant influence on atmospheric boundary layer, storm tracks, and large-scale atmospheric circulation. However, mechanisms governing how mesoscale sea surface temperature (SST) anomalies associated with oceanic eddies affect extratropical cyclogenesis remains unclear. Here, we investigate the influence of Kuroshio oceanic eddies on cyclogenesis in the North Pacific in high resolution climate model simulations using a cyclone tracking approach. Based on cyclone tracking and composite analyses, we find that presence of mesoscale SST anomalies almost doubles water vapor supply, leading to significant increase of diabatic heating release and eddy potential energy to eddy kinetic energy conversion and thus supporting stronger storm growth rate and intensified cyclones. This finding implies that moisture process is the key linking mesoscale oceanic eddies in the western boundary current regions with storm tracks in the midlatitude.