Banca de DEFESA: JEAN SOUZA DOS REIS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JEAN SOUZA DOS REIS
DATE: 30/11/2022
TIME: 08:00
LOCAL: Plataforma Google-Meet
TITLE:

DYNAMIC AND CLIMATOLOGICAL ASPECTS OF BOMB CYCLONES IN THE SOUTHERN HEMISPHERE

KEY WORDS:

Cyclone. Tracking. Dynamic. Extratropical

PAGES: 150
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Meteorologia
SPECIALTY: Meteorologia Sinótica
SUMMARY:

A Bomb Cyclone (BC) is an Extratropical Cyclone (EC) that presents a rapid pressure decay in the center of the system in the order of 1 hPa per hour for 24 hours. This system has gained popularity in recent years as it poses serious threats to the safety of maritime transport, 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, dynamic and phase characteristics of BC in the Southern Hemisphere 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 Systems Frontals (SF) in Natural Disasters (DN) in Southern Brazil. It is expected that the results can serve as a basis for improving 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. Reanalyzed data from the ERA5 set from the Europe Center for Medium-Range Weather Forecasts (ECMWF) were used, with a spatial resolution of 0.125°x0.125° and 2.5°x2.5° and a temporal resolution of 6 hours in the period from 1979 to 2019, natural disaster data kindly provided by the National Center for Monitoring and Alerts for Natural Disasters (Cemaden) from 2016 to 2020, daily accumulated precipitation data, estimated from the Integrated Multi-satellite Retrievals for GPM (IMERG) algorithm (version 5) of the mission of the Global Precipitation Measurement (GPM) 0.25°x0.25° from 2016 to 2020 and surface synoptic charts from the Weather Prediction Center for Climatic Studies/National Institute for Space Research (CPTEC/INPE) at the four main synoptic times (00, 06 , 12 and 18 UTC) from 2016 to 2020. For the detection and tracking of BC, a cyclone tracking scheme was used in pressure level fields at mean sea level every six hours. To evaluate the three-dimensional structure of cyclones, the Cyclone Phase Diagram (CPS) was used. Student's t-test, Shapiro-Wilk, Mann-Kendall, Pettit and Sen's estimation tests were used to determine the existence, magnitude and break point of the trend 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 HS 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 AS southeast of Uruguay over the South Atlantic Ocean, in the Southeast of mainland Australia and the Tasman Sea. The physical and dynamic characteristics, such as speed, lifetime, pressure gradient and penetration rate, showed good agreement with other works in the literature. There was a trend in the number of BC over the years with statistical evidence. There has been an increase of one BC every 4 years since 1999. Strong evidence has been identified that more than 35% of BC that form in the HS follow the theoretical cyclone model known as Shapiro-Keyser. In the evaluation of DN caused by the passage of a SF 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 FS that generate ND are different from the other FS that affect the South of Brazil. The main differences noted were: a pattern of increase and accumulation of convective potential energy available west of southern Brazil before the DN, 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. The analysis of the behavior of the rain indicates that it is higher in the two days before the disaster. The average values of precipitation identified, together with the observed atmospheric behavior, allow identifying the potential occurrence of a disaster in the cities of southern Brazil in the passage of a frontal system.

COMMITTEE MEMBERS:
Presidente - 1164414 - WEBER ANDRADE GONCALVES
Interno - 2086472 - BERGSON GUEDES BEZERRA
Interno - 1752417 - CLAUDIO MOISES SANTOS E SILVA
Interno - 1858120 - DAVID MENDES
Externo à Instituição - DIEGO OLIVEIRA DE SOUZA - CEMADEN
Externa à Instituição - SAMIRA DE AZEVEDO SANTOS - CTGás