A Tail of Two Models: Estimating the Annual Exceedance Probability of Probable Maximum Precipitation

Abstract

This paper describes the development and application of two largely independent methods to estimate the annual exceedance probability (AEP) of Probable Maximum Precipitation (PMP). One method is based on the Stochastic Storm Transposition (SST) approach, which combines the "arrival" and "transposition" probabilities of an extreme storm using the total probability theorem. The second method - termed "Stochastic Storm Regression" - combines frequency curves of point rainfalls with regression estimates of areal rainfalls; the regression relationship is derived using local and transposed storms, and the final exceedance probabilities are derived using the total probability theorem. The methods a..