Rainfall Intensity-Duration-Frequency Relations under Changing Climate for Selected Stations in the Tigray Region, Ethiopia

Abstract

Developing intensity, duration, and frequency (IDF) of rainfall with the reflection of future climate change is required for designing and managing water infrastructures. Hence, this study was aimed to predict future changes in IDF information for seven stations of the Tigray Region. Observed hourly and spatiotemporally downscaled Hadley Center Climate Model version 3 (HadCM3) model output data sets via Statistical Downscaling Model (SDSM) 4.2.9 and Hyetos models were used. Gumbel [Extreme Value Type I (EVI)] distribution and MIDUSS IDF Curve Fit tool were employed for frequency analysis and estimation of IDF equation parameters. Finally, general trends for three future climate timelines were established. The result revealed that the rainfall intensity is expected to decrease by 15.9%, 14.7%, and 20.3% for short storms and increase by 21.3%, 26.9%, and 18.9% for longer storms in the 2020s, 2050s, and 2080s, respectively, with frequent intensive rainfall occurrences by the 2020s and 2050s under the A2 emission scenario (high emission scenario). These have a great message to which the existing and future water management facilities are designed, functioned, and sustained. Thus, design facilities need to be updated as per the reflection of climate change impacts.