Projecting changes in extreme rainfall from three tropical cyclones using the design-rainfall approach

Anna M Jalowska,Jared H Bowden,Tanya L Spero

doi:10.1038/s41612-021-00176-9

Abstract

In the past quarter-century, Eastern North Carolina (ENC) experienced several devastating tropical cyclones that led to widespread flooding and damage. Historical climate records reflect an increasing trend in the frequency and intensity of extreme rainfall events across the eastern U.S., which is projected to continue to increase throughout the twenty-first century. Potential changes to extreme rainfall across ENC are explored and quantified for 2025–2100 for three tropical cyclones using an approach based on relative changes in future extreme rainfall frequencies (return periods) from dynamically downscaled projections. Maximum rainfall intensities at ‘2100’ could increase locally by 168%, with widespread regional increases in total rainfall up to 44%. Although these magnitudes exceed the consensus in the literature, the values here are comparable to the most extreme rainfall events observed in the U.S. during the early twenty-first century, which suggests that the intensity of projected future events is already a present-day reality.

Highlights

Extreme precipitation events driven by tropical cyclones (TCs) disrupt the quality of life in coastal plains and low-lying communities, where growing populations support important agricultural, environmental, cultural, and economic resources.there is a broad interest in quantifying the potential changes to extreme rainfall from TCs
This study quantifies projected increases in extreme precipitation associated with three devastating TCs under three scenarios using the DesignRainfall Approach (DRA) methodology while acknowledging sources of uncertainty in the approach and scenarios
The DRA is based on the RPs assigned to each cell using the current Atlas 1429 for Virginia, North Carolina and South Carolina, which omits over a dozen TCs including Matthew and Florence

Summary

Introduction

There is a broad interest in quantifying the potential changes to extreme rainfall from TCs. Over the past century, the southeastern U.S has increasingly recorded more extreme precipitation events[1]. Since 1910, much of the U.S has received a greater proportion of its total precipitation from intense one-day rainfall events[2]. During 1958–2016, there was a 27% increase in the 99th percentile precipitation[3] in the southeastern U.S During 1949–2018, TCs comprised 25 of the top 100, 4-day rainfall events nationwide[4]; with one-quarter of the top 100 events occurring in the final decade of the 70-yr record, at a far greater frequency than in any other decade. Throughout the mid-latitudes, extreme rainfall events will likely become more intense in a warmer world from increased tropospheric water vapor[5]. TC precipitation will likely increase globally, and a 2 °C warming could increase the median TC precipitation rate by 14% at constant relative humidity[7]

Methods

Results

Conclusion