Estimation of Storm-centered ARF Using Radar Rainfall by Duration and Return Periods

Abstract

Abstract-Design flood estimation, the application of the Areal Reduction Factor (ARF) is essential to convert the point rainfall to areal rainfall for the reference area. ARF calculation methods are largely divided into fixed-area method and storm-centered method. Since ARF is calculated by independent frequency analysis of maximum annual areal rainfall and point rainfall. On the other hand, storm-centered method is that make the maximum rainfall occur by spatial transition of each rainfall event to the center of the analysis watershed. Using the radar rainfall data, it is possible to calculate the real ARFs. In this study, the storm-centered ARFs were estimated by using radar data of the flood season (June to September) of 2007-2012 provided by Korea Meteorological Administration. Also, the center rainfall of the radar data were classified by the probability rainfall based on gauge rainfall data, and storm-centered ARFs were compared with fixed-area ARFs by duration and return period.

A storm-centered multivariate modeling of extreme precipitation frequency based on atmospheric water balance

“…ARFs are used to convert gauge-based (i.e., point-scale) precipitation frequency estimates to areal estimates of the same ARI and duration (e.g., Kao and Deneale, 2021;Miller, 1964;Olivera et al, 2008). Most ARF studies have tried to obtain such ratios using a "fixed-area" approach, i.e., to relate precipitation depth from point to area at a fixed location (e.g., Asquith and Famiglietti, 2000;Breinl et al, 2020;Durrans et al, 2002), though others have argued that stormcentered ARF approaches are more conceptually valid (Kim and Kang, 2017;Thorndahl et al, 2019;Wright et al, 2014). The ability to derive storm-centered DAD relationships using our method can, in principle, obviate the need for ARFs entirely, something that has been advocated previously (Wright et al, 2014).…”