Banca de DEFESA: LIZANDRO PEREIRA DE ABREU

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : LIZANDRO PEREIRA DE ABREU
DATA : 21/09/2018
HORA: 08:30
LOCAL: Auditório CCET
TÍTULO:

Lightning in the Northeast of Brazil: Occurrence, Variability, Seasonality and the relationship with cloud microphysics


PALAVRAS-CHAVES:

Remote sensing, lightning, TRMM, LIS, thunderclouds.


PÁGINAS: 130
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Meteorologia
ESPECIALIDADE: Meteorologia Física
RESUMO:

In the history of mankind, lightning has been the focus of scientific observation in many research groups around the world, mainly because of its aggressive and destructive nature. These important atmospheric phenomena can greatly impact the society, leading to abnormalities or disconnections in power distribution, fires, ship and airplane accidents, telecommunication breakdowns and even death. It is estimated that about 60-75 million lightning occur annually, killing an average of 132 people every year in Brazil. The Northeast region of Brazil (NEB) accounts for 18% of the total deaths in the national territory. Considering the population of all Brazilian regions, the state of Piauí presented the highest mortality rate (1.8 deaths per million); which is higher than the country’s total rate (0.8) and the NEB rate (0.5). Studies have shown that lightning formation is associated with the collision between ice particles (crystal and graupel) in the presence of supercooled water droplets in regions with strong updrafts. Therefore, the objective of this study is to evaluate lightning spatial and temporal distribution in NEB, as well as to investigate the relationship between lightning and cloud microphysics, during the period from 1998 to 2013. Data from two orbital plataforms were used: i) Lightning Imaging Sensor (LIS), TRMM Microwave Imager (TMI) and Precipitation Radar (PR) from the Tropical Rainfall Measuring Mission (TRMM) satellite to provide information on the occurrence of total lightning (intracloud and cloud-to-ground) and vertical content of the atmosphere (hydrometeors, precipitation rate, rain type); ii) Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), on board of Terra platform provide the ground elevation data, to verify the influence of topography on lightning rates. Data will be worked in monthly, seasonal and general distributions formats. The general distribution was worked out based on Cluster Analysis and aided the identification of the greatest points of lightning occurrence (hotspots). Finally, the lightning was analyzed according to the quantiles technique, finding the characterization according to the microphysical characteristics of clouds. In the NEB territory, it was registered great spatial and temporal variability in the lightning rates, with mean varying from 0 to 44.5 flashs.km-2.year-1. All the hotspots are located in Piauí, Maranhão states and west region of Bahia. The topography of NEB seems to act as a facilitator of the convective process, by the increases of intense updrafts formation, an essential factor for the generation of electric charges inside the thunderclouds. The cluster analysis together with the investigation of the characteristics of each of the hostspots allowed to infer that the Intertropical Convergence Zone (ITCZ) and Mesoscale Convective Systems (MCS) are the systems most associated with lightning in NEB territory, being the lightning hotspots characterized as occurrence sites of these systems. Regarding the microphysical parameters of the cloud, it was observed that when the lightning happens, the atmosphere has lower values of liquid water in the cloud, high amounts of ice water, high convective precipitation rate, lift of height freezing level and high probability of precipitation (or the occurrence of this); this information allowed the conceptual model proposition of the microphysical characteristics present when lightning occurs in the NEB.


MEMBROS DA BANCA:
Presidente - 1164414 - WEBER ANDRADE GONCALVES
Interno - 1752417 - CLAUDIO MOISES SANTOS E SILVA
Interno - 320597 - PAULO SERGIO LUCIO
Externo à Instituição - ENRIQUE VIEIRA MATTOS - UNIFEI - UNI
Notícia cadastrada em: 13/09/2018 14:37
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