Banca de DEFESA: CLEBSON CARVALHO DE FARIAS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : CLEBSON CARVALHO DE FARIAS
DATE: 31/03/2022
TIME: 07:30
LOCAL: Google Meet
TITLE:

RECONHECENDO EVENTOS HIDROLÓGICOS: INDISSOCIANDO MAGNITUDE
EXTREMA, DURAÇÃO E PERÍODO DE OCORRÊNCIA NA ANÁLISE DE FREQUÊNCIA
(RARIDADE)

KEY WORDS:

Copulas, Indicators of hydrologic alteration (IHA), Multivariate frequency analysis;
Extreme value analysis.

PAGES: 33
BIG AREA: Engenharias
AREA: Engenharia Sanitária
SUBÁREA: Recursos Hídricos
SPECIALTY: Planejamento Integrado dos Recursos Hídricos
SUMMARY:

With the need to analyze the aspects of events with methods that present fewer uncertainties.
This work aims to propose a new approach in order to reduce the uncertainties in the analysis
of hydrological events considering the different variables of an event as interdependent, thus
obtaining more information about the events. The study was applied to the São Francisco
River basin, the river of national integration that suffers from different anthropic actions, from
the Xingó station with observed flow data provided by the Companhia Hidrelétrica do São
Francisco (CHESF)/SAR of ANA, and natural data reconstituted by the Operador Nacional
do Sistema Elétrico (ONS), the data are available for the period 1976-2018 for observed data
and 1931-2018 for natural data. Event analyses usually consider one variable, maximum or
minimum magnitude per year. Currently, the use of copula functions is increasing in multivariate
analysis of hydrological events, as it is known that it is necessary to consider more information
about the events. In Hydrological Alteration Indicators (HAI), a method to obtain information
about alteration of a regime by anthropic actions, the frequencies of the aspects (aggregation
of variables) of an event are analyzed considering the independent variables. However, in
this work, copula functions were applied to analyze the aspects (aggregating variable) of an
event considering its variables as being dependent. The variables flow, duration and period of
occurrence are the ones chosen for this work, and the marginal distributions for each variable,
respectively, Generalized Pareto (GP), Pearson 3, and Von Mises (floods) and Normal (droughts).
The Gaussian copula showed the best results in the goodness of fit tests for modeling the flood
and drought events, while the Archimedean copulas had satisfactory results for the flood events
and unsatisfactory results for the drought events. A new approach for hydrological regime change
analysis was introduced, thus showing changes in the flow regime of the São Francisco River.

BANKING MEMBERS:
Presidente - 1718531 - CARLOS RUBERTO FRAGOSO JUNIOR
Interno - 1640249 - MARLLUS GUSTAVO FERREIRA PASSOS DAS NEVES
Externo ao Programa - 1716469 - CHRISTOPHER FREIRE SOUZA
Externo à Instituição - ANDREA SOUSA FONTES - UFRB