Three methods of characterizing climate-induced changes in extreme rainfall: a comparison study

Abstract

(1) Three practical and easily implementable methods are provided to estimate percent increases in extreme rainfall due to climate change for the period 2020–2090 using Global Climate Model (GCM) output. (2) Methods are designed to bracket the expected range of extreme rainfall intensification for 1–24-h events with return intervals of 1 year to 100 years. (3) One method is based on the 20 largest wet days produced by an ensemble of GCMs, and the other two use GCM projections of temperature and Clausius–Clapeyron assumptions. (4) The results of the case study for the Philadelphia area show that, by the end-of-century, extreme rain event volumes might increase from a low of 18% to a high of 61%, depending on the duration and return interval under consideration. (5) Methods have been benchmarked against existing, publicly available projected rainfall intensities to show the methods that provide an accurate range of extreme rainfall intensification due to climate change. HIGHLIGHTS Three practical methods to assess changes in extreme rainfall are provided.; Method benchmarked against five publicly available national databases.; Brackets plausible range of storm intensification for planning and risk assessments.; Change factors for 1-year to 100-year return intervals for daily and subdaily storm event durations relevant to urban flood applications are provided.; Case study application for Philadelphia.;

Keywords

• clausius–clapeyron
• climate change
• extreme rainfall
• flooding
• future precipitation projections
• global climate model