Mathematical modeling and simulation of hourly precipitation through rectangular pulses/Modelagem matematica e simulacao da precipitacao horaria por meio de pulsos retangulares

• Published in: Acta scientiarum. Agronomy 2011-10, Vol.33 (4), p.565
• Main Authors: Uggioni, Edison, Back, Alvaro Jose, Vieira, Hamilton Justino
• Format: Article
• Language: Spanish
• ISSN: 1679-9275
• DOI: 10.4025/actasciagron.v33i4.7052

The recorded historical series of precipitation are usually available for short periods of time and with many failures. The use of mathematical modeling to simulate rainfall is a tool used to circumvent this problem and to simulate the operation of water systems in different scenarios. The present study applies mathematical modeling to the hourly pluviometric precipitation data simulation. A pluviographical data set from October 1980 to December 2007 was used in the study. Precipitation data sets were obtained through daily pluviometric digitalization from the Meteorologic Station of Epagri at Urussanga, in southern Santa Catarina, Brazil (latitude 28°31' S and longitude 48°19' W). To simulate the hourly rain series, the stochastic model was modified based on the Bartlett-Lewis rectangular pulses model with six parameters. Those parameters were fitted by minimizing a function related to the analytical expressions that define the average, variance, and autocorrelation coefficient at lag 1 and the probability of a dry period related to the estimated values from the observed data. Ten series were simulated for 100 years of data. Data analyses and results showed that fitting Bartlett-Lewis model parameters makes it possible to simulate hourly rainfall while preserving precipitation statistical properties at several temporal aggregation levels. In general, the probability of dry periods tended to be overestimated. Keywords: hydrology, rainfall, simulation, probability, stochastic models. As series historicas de precipitacao disponivel, geralmente, sao relativamente curtas e com muitas falhas nas observacoes. A utilizacao da modelagem matematica para simulacao de chuvas e uma ferramenta utilizada para contornar esse problema, possibilitando a simulacao do funcionamento de sistemas hidrologicos em diferentes cenarios. Este trabalho teve como objetivo aplicar a modelagem matematica na simulacao de serie de dados de precipitacao horaria. Foi utilizada a serie de dados pluviograficos do periodo de outubro de 1980 a dezembro de 2007. Os dados de precipitacao foram obtidos pela digitalizacao dos pluviogramas diarios da Estacao Meteorologica da Epagri, Urussanga, Sul de Santa Catarina (latitude 28°31' S, longitude 48° 19' W). Para a simulacao das series de chuva horaria, o modelo estocastico adotado foi o modelo de pulsos retangulares de Bartlett-Lewis modificado com seis parametros. O ajuste dos parametros foi realizado tendo como base a minimizacao da funcao relacion