Regionalization of Multiplicative Random Cascade Model Parameter for Awash River Basin, Ethiopia

Abstract

Data on fine-resolution precipitation are necessary for the design of hydraulic structures, the estimation of rainfall erosivity, and the assessment of urban hydrological climate change. In Ethiopia, precipitation data are typically available on a daily or monthly basis. The number of weather stations equipped with automatic gauges for measuring precipitation rates is small. Therefore, a scientific approach is required to disaggregate existing coarser resolution rainfall data to finer resolution. It is also necessary to regionalize the developed disaggregation models to simulate sub-hourly rainfall data across a wide region. The multiplicative cascade models appear to be interesting instruments for simulating fine-resolution rainfall because of its connection to the multifractal theory. Thus, the study aims to regionalize random cascade model (RCM) parameters and analyze their potential and limitations. The newly developed regional models are tested on rainfall data of Awash River Basin in Ethiopia. The models demonstrated acceptable accuracy in simulating the sub-hourly rainfall, demonstrating the potential of parameter regionalization.