Gonçalves, Weber AndradeReis, Jean Souza dos2023-05-172023-05-172022-11-30REIS, Jean Souza dos. Aspectos dinâmicos e climatológicos dos ciclones bombas no Hemisfério Sul. Orientador: Weber Andrade Gonçalves. 2022. 128f. Tese (Doutorado em Ciências Climáticas) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2022.https://repositorio.ufrn.br/handle/123456789/52470A Bomb Cyclone (BC) is an Extratropical Cyclone (EC) of rapid pressure drop at the center of the system on the order of 1 hPa per hour for 24 hours. This system has gained popularity in recent years for imposing serious threats to the safety of shipping, fishing, maritime operations and other activities in coastal regions and the recent impacts on the population. Therefore, the purpose of this study is to analyze the physical characteristics, dynamics, and phase of BC in the Southern Hemisphere (SH) through a robust climatology from 1979 to 2020. In addition, the existence of a trend in the number of BC over time and the influence of frontal systems (FS) on natural disasters (ND) in Southern Brazil. It is hoped that the results can serve as a basis for improved services such as numerical simulations and be used as prognostics to assist in risk management with a set of preventive and mitigating actions in order to minimize the impact of these systems suffered by the population. We used reanalyzed ensemble ERA5 data from the Europe Center for Medium-Range Weather Forecasts (ECMWF), with spatial resolution of 0.125°x0.125° and 2.5°x2. 5° and 6-hour temporal over the period 1979 to 2019, natural disaster data kindly provided by the Centro Nacional de Monitoramento e Alertas de Desastres Naturais (Cemaden) from 2016 to 2020, daily cumulative precipitation data estimated from the Integrated Multi-satellite Retrievals for GPM (IMERG) algorithm (version 5) of the Global Precipitation Measurement (GPM) 0. 25°x0.25° from 2016 to 2020 and surface synoptic charts from the Center for Weather Forecasting Climate Studies/National Institute for Space Research (CPTEC/INPE) at the four major synoptic times (00, 06, 12, and 18 UTC) from 2016 to 2020. For BC detection and tracking, a cyclone tracking scheme was used on mid-sea level pressure fields every six hours. To evaluate the three-dimensional structure of cyclones, the Cyclone Phase Space (CPS) was used. The statistical tests Student's test-t, Shapiro-Wilk, Mann-Kendall, Pettit and Sen's estimation were used to determine the existence, magnitude and trend breaking point in the BC time series. The total number of BC was 587, with the highest occurrence (44.2%) in winter and the lowest (6.1%) in summer. The spatial density of BC in the SH showed good agreement with that seen in the literature, seen mainly around Antarctica in a kind of spiral around it, in the cyclogenetic area of SSA southeast of Uruguay over the South Atlantic Ocean, in the southeast of the Australian continent, and in the Tasman Sea. The physical and dynamic characteristics such as: velocity, lifetime, pressure gradient and deepening rate, showed good agreement with other works in the literature. It was found that there is a trend in the number of BC over the years with statistical evidence. There is an increase of one BC every 4 years since 1999. Strong evidence was identified that over 35% of BC that form in the SH follow the theoretical cyclone model known as ShapiroKeyser. In the evaluation of ND caused by the passage of a FS over southern Brazil, it was observed that the most affected regions are the coast of Santa Catarina and the central-eastern region of Rio Grande do Sul. In addition, it was found that the frontal systems that generate natural disasters are different from the other frontal systems that affect Southern Brazil. The main differences noted were: a pattern of increase and accumulation of available convective potential energy west of Southern Brazil prior to ND, especially in spring; a considerable increase in specific humidity at low levels associated with runoff east of the Andes; and an anticyclonic circulation at high levels similar to the Bolivian high. Analysis of rainfall behavior indicates that it is highest on the two days prior to the disaster. The mean precipitation values identified, together with the observed atmospheric behavior, allow the identification of the potential occurrence of a disaster in the cities of southern Brazil in the passage of a frontal system.Acesso AbertoClimatologiaCicloneRastreamentoDinâmicaExtratropicaldoctoralThesisCNPQ::CIENCIAS EXATAS E DA TERRA