Intensity-duration-frequency curves at the global scale

Laurent G Courty,Louise J Slater,John K Hillier,Robert L Wilby

doi:10.1088/1748-9326/ab370a

Laurent G Courty, Louise J Slater + Show 2 more

Open Access

https://doi.org/10.1088/1748-9326/ab370a

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Abstract

Intensity-duration-frequency (IDF) curves usefully quantify extreme precipitation over various durations and return periods for engineering design. Unfortunately, sparse, infrequent, or short observations hinder the creation of robust IDF curves in many locations. This paper presents the first global, multi-temporal (1–360 h) dataset of generalized extreme value (GEV) parameters at 31 km resolution dubbed PXR-2 (Parametrized eXtreme Rain). Using these data we generalize site-specific studies to show that that GEV parameters typically scale robustly with event duration (r2 > 0.88). Thus, we propose a universal IDF formula that allows estimates of rainfall intensity for a continuous range of durations (PXR-4). This parameter scaling property opens the door to estimating sub-daily IDF from daily records. We evaluate this characteristic for selected global cities and a high-density rain gauge network in the United Kingdom. We find that intensities estimated with PXR-4 are within ±20% of PXR-2 for durations ranging between 2 and 360 h. PXR is immediately usable by earth scientists studying global precipitation extremes and a promising proof-of-concept for engineers designing infrastructure in data-scarce regions.

Highlights

Historical precipitation records are widely employed by civil engineers to compute Intensity–Duration–Frequency (IDF) curves, which are essential for the design of infrastructure like highways (e.g. Brown et al, 2013; NYS DoT, 2018), urban drainage networks (e.g. Battaglia et al, 2003; Brown et al, 2013) and dams (e.g. NYS DoEC, 1989)
The Parameterized eXtreme Rainfall–2 (PXR-2) dataset comprises worldwide Generalized Extreme Value (GEV) parameters estimated from the ERA5 data for all 19 durations (1 h to 360 h), along with their uncertainties
Our results demonstrate the promising applicability of 1) reanalysis data to estimate IDF relationships, and 2) daily rainfall records to estimate subdaily IDF curves

Summary

Introduction

Historical precipitation records are widely employed by civil engineers to compute Intensity–Duration–Frequency (IDF) curves, which are essential for the design of infrastructure like highways (e.g. Brown et al, 2013; NYS DoT, 2018), urban drainage networks (e.g. Battaglia et al, 2003; Brown et al, 2013) and dams (e.g. NYS DoEC, 1989). IDF curves are used to create synthetic rainfalls that permit the sizing of structures for a given return period, often required by local regulations. Much new infrastructure is being built in regions where the historical record of precipitation is scarce or uncertain, hindering adequate sizing of waterrelated works. One more sophisticated approach consists of analyzing regional precipitation patterns to estimate local characteristics such as IDF curves at the location of interest (e.g. Roux and Desbordes, 1996; Fowler and Kilsby, 2003; Domínguez et al, 2018).

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