A stochastic framework for rainfall intensity–timescale–return period relationships. Part I: Theory and estimation strategies

Abstract

This work presents a stochastic framework for the construction of rainfall intensity–timescale–return period relationships, which was applied in the recent regionalization of design rainfall curves over the Greek territory, described in a companion paper. The methodology outlined herein builds upon the Koutsoyiannis’ et al. 1998 framework, which has been recently revisited and upgraded, and incorporates two different versions: (a) a theoretically consistent stochastic model applicable for rainfall intensity over any scale of interest and (b) a simplified version valid over small scales, which makes parameter estimation easier. Special focus is given to the presentation of the simplified version, which suffices for most engineering tasks. Parameter estimation approaches are presented in detail including the K-moments framework that allows for reliable high-order moment estimation and handling of bias due to spatiotemporal dependence.