Métodos de desagregação na geração de equações IDF: estudo comparativo aplicado a municípios cearenses providos de pluviógrafos

• Autor(a) principal: Oliveira, Dayanne Rodrigues
• Data de Publicação: 2021
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/57882
• topic: Chuvas intensas; Equação IDF; Desagregação

For a better design of urban hydraulic structures it is necessary to know the relationship between intensity, duration and frequency of heavy rainfall. These are usually associated with short durations. Due to the small network of rain gauges and the vast availability of historical series of rainfall data in Brazil, it is common to use methods of disaggregating daily rainfall, those recorded in rain gauges, into rainfall of shorter durations. This work aims to evaluate the performance of three disaggregation methods building IDF equations for the municipalities of Fortaleza - CE and Quixeramobim - CE, both provided with rain gauge equations, from historical series of maximum daily precipitation. Five probability distributions were tested to calculate the recurrence time or frequency of events. The disaggregation methodologies developed by Bell (1969) and adapted by Righetto (1998), by the Environmental Company of the State of São Paulo (CETESB) in 1979 the traditional and the alternative model proposed by Back (2020), and the isozone methodology proposed by Taborga Torrico (1974) were applied. The adjustment of the parameters of the equations built for the two municipalities was verified by calculating the NASH coefficient, the Standard Error of Estimation and analysis of the S function, which is the sum of the squares of the deviations. To analyze the performance of the equations developed in this work, a comparison was made between them and the rain gauge equation of each municipality, analyzing the Performance Index and the correlation of the values. The alternative model proposed by Back (2020) presented the best fits, with NASH coefficient equal to 1 and lower S values for the two municipalities. The methodology proposed by Taborga Torrico (1974) was the one that presented the best performance when compared to the IDF equation of rain gauge in the city of Fortaleza - CE with a performance index of 97%. For Quixeramobim the method with the highest performance index was Bell's, with an average value of 91%, followed by the method of Taborga Torrico (1974) with 87%. However, the regression line of the values obtained by Bell's method showed the smallest angular coefficient and, therefore, the method is the one that most underestimates the values of the intensities compared to the results obtained by the standard equation.