Modelagem de curvas IDF em condições de escassez de dados sub-horários em Goiás: impactos da escolha do procedimento de estimação e da distribuição

Abstract

This study conducts a comparative evaluation between two procedures for constructing Intensity–Duration–Frequency (IDF) curves from sub-daily rainfall series with high temporal resolution, obtained from the CEMADEN network in the state of Goiás. The Single-Step Procedure (SSP), based on joint global calibration, and the Standard Procedure (SP), calibrated individually by duration, are analyzed for statistical performance and suitability for engineering applications. The series used are relatively short (approximately 9 years). The evaluation considers classical statistical goodness-of-fit and error metrics, as well as comparisons with existing curves commonly used in local practice, in order to reduce the bias associated with the short length of the samples. The results indicate that the SSP tends to exhibit greater internal consistency with calibration data and greater functional consistency across time periods, while the SP may produce estimates more consistent with regional patterns in certain situations. On average, both procedures show similar performance when compared to existing curves, demonstrating that local statistical superiority does not necessarily imply greater suitability for design purposes. It is concluded that the use of modern high-resolution time series is promising for urban hydrological applications; however, it must be accompanied by an assessment of regional consistency, a critical analysis of extrapolations, and, whenever possible, a combination of methodological approaches, in order to ensure greater physical robustness and reliability of extreme precipitation estimates.