Author(s): H. Tabari; P. Hosseinzadehtalaei; P. Willems; S. Saeed; E. Brisson; N. Van Lipzig
Keywords: No keywords
Abstract: The design statistics for water infrastructures are typically derived from rainfall intensity–duration–frequency (IDF) curves which compound frequency and intensity aspects of rainfall events for different durations. Current IDF curves are constructed based on historical time series, with an underlying temporal stationarity assumption for the probability distribution of extreme values. However, climate change casts doubt on the validity of this assumption due to ongoing and projected changes in the intensity and frequency of extreme rainfall. In this study, IDF curves for historical periods obtained from the convection permitting CCLM model with spatial and temporal resolutions of 2.8 km and 15 minutes and an ensemble of climate models (CMIP5) are validated based on observations-based curves. After this validation, future climate IDF relationships are obtained based on a quantile perturbation approach. It is concluded that the sub-hourly precipitation intensities at 15 and30 minutes in the IDF curves derived from the CCLM 2.8 km model underestimate the observed extreme rainfall intensities. For the daily intensities, less deviation is observed for both the CCLM and the CMIP5 GCM runs. Future climate projections show potentially strong changes in extreme rainfall intensities, making the historical climate based IDF design standards unsuitable for the future extreme events.