Temporal change of extreme precipitation intensity–duration–frequency relationships in Thailand

Abstract

Due to climate change, many research studies have derived the updated extreme precipitation intensity–duration–frequency relationship (IDF curve) from forecasted sub-hourly rainfall intensity time series, which is one of the most important tools for the planning and designing of hydraulic infrastructures. In this study, the IDF curves (1990–2016) of the six regions and procedures are used in accordance with those of the Royal Irrigation Department (RID)’s study (1950–1988). Each set of IDF relationships consists of 81 intensity values which are the combination of nine durations and nine return periods. The intensity ratios of this study and RID are compared. A greater-than-1 ratio indicates extreme intensity increment from the past to the present. Considering 81 ratios for each region, the number of greater-than-1 ratios for the North, Northeast, Central, East, West, and South regions are 8, 2, 31, 34, 6, and 7, respectively. These ratio numbers are far below 81 which means that the majority of extreme rainfall intensities do not increase from the past to the present. The study found that using accurate historical sub-hourly rainfall time series to create a set of IDF curves would be more reliable than using forecasted rainfall modeling.

Estimation of regional intensity–duration–frequency relationships of extreme rainfall by simple scaling in Thailand

“…Utilizing the Long Ashton Research Station Weather Generator (LARS-WG), a stochastic weather generator, and the rainfall disaggregation tool Hyetos, they investigated a methodology based on the spatial downscaling-temporal disaggregation method (DDM) to develop future IDFs. Additionally, Yamoat et al (2022) developed IDF curves for six regions of Thailand, i.e., the Northern, Northeastern, Central, Western, Eastern, and Southern regions. They found that using accurate historical sub-hourly rainfall time series to create a set of IDF curves would be more reliable than using forecasted rainfall modeling.…”

Equação de chuvas intensas de longa duração para Santa Catarina, Brasil

“…A chuva de projeto deve considerar a relação entre a intensidade, duração e frequência, denominada de relações IDF (MIRHOSSEINI et al, 2012;SUN et al, 2019). Alguns autores usam a relação altura ou profundidade no lugar da intensidade, denominando de relação DDF (YAMOAT et al, 2022). Essas relações podem ser expressas de forma gráfica, as chamadas curvas IDF, ou por meio de equações, denominadas de equações IDF (ou DDF).…”