A Global Climatology of Extratropical Transition. Part I: Characteristics across Basins

• DOI: 10.1175/jcli-d-17-0518.1
• Publication Date: 2019-03-28T19:59:39Z
• Authors: Melanie Bieli; Suzana J. Camargo; Adam H. Sobel; Jenni L. Evans; Timothy Hall
• Keywords: Extratropical cyclone; Geopotential height; Storm track

Abstract The authors present a global climatology of tropical cyclones (TCs) that undergo extratropical transition (ET). ET is objectively defined based on TC’s trajectory through the cyclone phase space (CPS), which calculated using storm tracks from 1979–2017 best track data and geopotential height fields reanalysis datasets. Two reanalyses are used compared for this purpose, Japanese 55-yr Reanalysis ECMWF interim reanalysis. results to study seasonal geographical distributions storms undergoing interbasin differences in statistics occurrence. About 50% all TCs North Atlantic western Pacific ET. In Southern Hemisphere, fractions range about 20% south Indian Ocean Australian region 45% South Pacific. majority ETs, become thermally asymmetric before forming cold core. However, substantial fraction take reverse pathway, developing core becoming asymmetric. This pathway most common eastern Atlantic. Different pathways can be linked different trajectories environmental settings. ETs over warmer sea surface temperatures, tend lose their thermal symmetry while still maintaining warm Landfalls by occur 3–4 times per year 7–10 Pacific, coastal regions affected once every 1–2 years.