Disaggregation coefficients for obtaining rainfall intensity-duration-frequency curves: concepts, models, errors and trends in Minas Gerais, Brazil

ABSTRACT

Sub-daily rainfall datasets are not commonly available in developing countries, but the annual maximum daily rainfall (P_ma) often is. This article evaluates the ratio between 1440 min of rainfall and the P_ma, as well as the sub-daily rainfall ratio from different origins as disaggregation coefficients for modeling the intensity-duration-frequency (IDF) curves in the metropolitan area of Belo Horizonte, Brazil. Non-parametric tests were previously applied to the series to verify stationarity, homogeneity, randomness, and independence. It was verified via Student’s t-test and identity test models that there is a significant difference between the IDF curves from the sub-daily rainfall dataset and disaggregation rainfall dataset. Nevertheless, the model performance indexes between the results of IDF curves indicate the errors are acceptable, thus guaranteeing an alternative tool in places where there are no sub-daily rainfall datasets available. Sub-daily rainfall ratios can be used as disaggregation coefficients on a local and regional scale.

KEYWORDS:

• Extreme rainfall
• sub-daily rainfall
• trend analysis
• non-stationarity

Acknowledgements

The authors would like to thank the Federal University of Viçosa, the Department of Agricultural Engineering and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed https://doi.org/10.1080/1573062X.2022.2105237