Updated Canonical Rainfall Distributions in the United States

Abstract

Previous research has identified five canonical rainfall distributions in the United States; however, identification of these rainfall distributions did not include any rainfall data in the state of Texas. In this study, data from 813 rainfall stations in Texas are used to update the canonical distributions, which are then extended to include Texas. Canonical rainfall distributions are extracted using cluster analysis, which identifies distinct rainfall distributions that are not statistically different from measured rainfall distributions. Novel findings of this study are that the canonical intensity-duration functions for all canonical rainfall clusters in the United States can be expressed in a single functional form, and the canonical rainfall distributions and canonical intensity-duration functions are not very sensitive to return periods in the range of 5–25 years, with the effect of the return period being mostly accounted for in the specification of the 24-h rainfall amount.