Alternative model of intense rainfall equation obtained from daily rainfall disaggregation

Abstract

The objective of this work was to propose an alternative model of IDF equation based on the disaggregation of daily rainfall. Data from the rainfall gauge station code 02649018 of the Brazilian National Water Agency from the period 1968 to 2011 were used. Several extreme event probability distributions were adjusted. Rainfall intensity with a return period of 2 to 100 years and durations of 5 to 1440 minutes were estimated using the relationships between rainfall for different durations. The four coefficients of the traditionally used IDF equation were adjusted, obtaining a sum of squares of deviations equal to 695.1 (mm.h-1)2 and standard error of estimation equal to 2.69 mm.h-1. For the model of the intense rainfall equation proposed, that relates the rain intensity and duration with the maximum daily rainfall, the sum of squares of the deviations was 33.6 (mm.h-1)2 and the standard estimated error was 0.59 mm.h-1. Including the return period in the model, we obtained squares of the deviations of 129.4 (mm.h-1)2, with a standard error of estimation of 1.16 mm.h-1. The models proposed have, besides better estimation accuracy, the advantages of facilitating the updating only by updating the maximum daily precipitation and sub serve the spatial representation.

Estimating surface flow based on the equation of heavy rain type LnLn / Estimativa do escoamento superficial baseado na equação de chuvas intensas do tipo LnLn

“…A limitation to the use of the method developed by Pruski et al (1997) is the dependence of the intense rainfall equations in the IDF model. Although the intense rainfall equations of the IDF model are the most used in Brazil and several other countries (Back & Cadorin, 2021), there are other intense rainfall equation models or even other methods of obtaining intense rainfall by disaggregating daily rainfall (Aragão et al, 2013;Rangel & Hartwig, 2016;Back, 2020). Back et al (2020) adapted the runoff estimation method developed by Pruski et al (1997) to be applied to the alternative model of the intense rainfall equation based on the disaggregation of the maximum daily rainfall.…”

Assessing intensity-duration-frequency equations and spatialization techniques across the Grande River Basin in the state of Bahia, Brazil

“…An alternative to aforementioned difficulties is using disaggregation indices in daily rainfall data series, i.e., from pluviometric stations (Back, 2020). In Brazil the most used method for disaggregation is that by CETESB (Aragão et al, 2013), which, albeit not based on a rigorous mathematical formalism, relies, to some extent, on the self-similarity rationale (Serinaldi, 2010) for linking maximum rainfall intensities across short time scales over large regions.…”

Daily Rainfall Disaggregation Coefficients for the Doce River Basin, Brazil: Regional Applicability and the Return Period Influence

“…However, the determination of the IDF ratios for short-term rainfall requires long series of rainfall data and requires a great deal of effort in the tabulation, processing, analysis and interpretation of large numbers of pluviograms data (Bielenki Júnior et al, 2016;Cecílio & Pruski, 2003;Dorneles et al, 2019). Moreover, the pluviographic series, besides a smaller number, have generally shorter periods and with more failures than the pluviometric series (Back, 2020). This has led to the use of relations that allow the estimation of critical rainfall based on pluviometric data, i.e., using daily rainfall data (Silva & Oliveira, 2017), since in Brazil, there is an extensive pluviometric monitoring network (Dorneles et al, 2019).…”