COMPARATIVE-EVALUATION OF POISSON PARTIAL DURATION MODELS FOR MIXED FLOOD POPULATIONS

Simple homogeneous formulations of two extreme value partial duration flood models are compared to more sophisticated compound formulations in terms of asymptotic performance of quantile estimates. The compound model formulations were developed to model flood series resulting fro m mixed climatological processes. It was found that only in the case o f marked nonhomogeneity in the data samples and the compound formulati on of the model., offer significant advantages in terms of variance of quantile estimates. However, the estimates from the homogeneous model were significantly biased in the negative direction- This negative bi as of quantile estimates from the simple model was even more pronounce d when the more sophisticated Weibull model was used as the base.