Thermal Structure Evolution of a Tropical Cyclone and its Extratropical Transition: Talim Case

Abstract The scientific community has long considered the existence of only two types of surface synoptic scale cyclones, tropical and extratropical, based on their genesis area. The Cyclone Phase Space (CPS) methodology developed by Hart in the early 2000s made it clear that these are not the only existing types of cyclone, but instead there is a continuum, and therefore cyclones can evolve from one type to another. Given this context, the objective of this study is to describe the synoptic evolution of the transition of cyclone Talim, which had genesis as a tropical cyclone and decayed as an extratropical cyclone. This system developed in the west of the North Pacific Ocean on September 10, 2017. Through the CPS, four phases of Talim's life cycle were selected: tropical cyclone, beginning of extratropical transition, end of transition and extratropical cyclone phase. The transition phase was marked by the beginning of the interaction of the tropical system with a baroclinic region, while the end of the transition occurred when the system acquired a cold core and had frontal systems associated.