Abstract

Of all the Tropical Cyclones (TC) that occur worldwide, 42% (27%) of the North Atlantic (western North Pacific) storms undergo Extratropical Transition (ET) into Extratropical Cyclones (EC). EC are asymmetric cold core systems as opposed to their warm core predecessors, and their radii of gale fo... Show moreOf all the Tropical Cyclones (TC) that occur worldwide, 42% (27%) of the North Atlantic (western North Pacific) storms undergo Extratropical Transition (ET) into Extratropical Cyclones (EC). EC are asymmetric cold core systems as opposed to their warm core predecessors, and their radii of gale force winds (17ms⁝š) may increase by a factor of two to three times their original radii. This expansion of the gale force winds can cause a significant amount of damage. In addition, these ET can trigger and amplify upper atmospheric waves, indirectly leading to the generation of other powerful storms across the world, which makes it imperative to study the dynamics and energetics involved with the ET. The ET of TC Sinlaku (2008), with the aid of a 500mb shortwave, was well observed through an international field campaign, THORPEX Pacific-Asian Regional Campaign (T-PARC). To understand the effects of latent heating when Sinlaku transitioned, this study has followed similar techniques to Kuo et al. (1990). Two different sets of simulations using the Weather Research and Forecasting (WRF) model with the Advance Research WRF core were conducted, involving a full set of physics and fake dry physics (neglecting latent heating). This study looked at the evolution of Horizontal Kinetic Energy and its components to examine the impact of latent heating on the energetics of of the ET processes. Results drawn from both simulations suggest that latent heating is crucial for the maintenance of the TC and the 500 mb trough, and for the ET process. This is clearly reflected by the significant differences in the kinetic energy of the two ARW simulations with and without latent heating. Show less