Chuvas Intensas No Estado De São Paulo: Estudos Existentes E Análise Comparativa

Disaggregation of daily rainfall data for the Caraguatatuba city, in São Paulo State, Brazil

“…Both Bell (1969) and Chen (1983) have developed similar techniques, using different forms of relationship time-duration and frequency for any place in the United States. Genovez and Zuffo (2000) complement Bell (1969) and conclude that empirical disaggregation coefficients do not replace rain gauge information of any site in study, but may assist with a reasonable estimate for regions where pluviographs data are scarce and only pluviometer(s) data are available.…”

“…Reduced observation periods are prone to criticism because short historical series are subject to statistical fluctuations, which can result in "false" maxima rainfall. According to Genovez and Zuffo (2000), in the second edition of Pfafstetter's work (Pfafstetter, 1982), 25 years later, there was no change in the data. For this reason, these authors recommend the use of the referred work only when one doesn't have more adequate data.…”

“…There are several other published works about rainfall disaggregation coefficients: Occhipinti and Santos (1966) developed such coefficients for São Paulo city, while Taborga (1974) and CETESB (1986) generalized it throughout Brazil; Cardoso et al (1998) developed the same work specifically for Santa Catarina, while Genovez and Zuffo (2000) have done it for some cities in São Paulo State. Silveira (2000) did the same for the Rio Grande do Sul, while Back (2009) and Back et al (2012), do it for Santa Catarina.…”

“…Therefore, CETESB (1986) stresses that generalization of disaggregation coefficient of rainfall from "1-day" to "24 hours" should be viewed with reservation, since unfortunately there wasn't in Brazil research of the same nature that produced these figures in the United States. Another point highlighted by Genovez and Zuffo (2000) is that the disaggregation coefficients presented are based on very short periods to be admitted as representative for the whole country. Back et al (2012) complement that national average values should be revised for those of regional averages, contemplating, therefore, the predominant precipitations in each region.…”

“…Furthermore, Genovez and Zuffo (2000) warn that the use of different coefficients for transforming daily rainfall into "24 hours" rainfall, even if they are close, introduce differences between the methods of determination of IDF curves. Bell (1969) adds that the correlations do not vary significantly in relation to the return period, i.e.…”