The Rapid Intensification of East Asian Cyclones Around the Korean Peninsula and Their Surface Impacts

Abstract

The rapid intensification of extratropical cyclones (ETCs) around the Korean peninsula and their surface impacts are investigated by detecting and tracking ETCs in East Asia using ERA-Interim data over the period of 1979-2017. The ETCs approaching the Korean peninsula, identified on the 850-hPa relative vorticity field, are mainly initiated in the leeward side of the Altai-Sayan Mountains and southern Tibetan Plateau, featuring northern and southern cyclone tracks, respectively. The northern-track ETCs are typically accompanied by a developing upper-level trough. In particular, those that intensify rapidly are characterized by a strong upper-level potential vorticity (PV) anomaly related to the enhanced trough, with a rather weak influence of diabatic heating. This is in contrast with the southern-track ETCs, which are primarily organized by a lower-level PV anomaly produced by diabatic heating. The southern-track ETCs rapidly intensify in the presence of a migrating upper-level trough through the interaction of upper- and lower-level PV anomalies. Although their intensification processes differ, surface winds reaching 10 m s(-1) are observed with the rapid intensification of both northern- and southern-track ETCs. The southern-track ETCs, traveling across the East China Sea and the Yellow Sea, also result in substantial precipitation in Korea and Japan.