Workshop on Statistical and Mathematical Methods for Hydrological Analysis – Rome May 2003 RAINFALL DISAGGREGATION METHODS: THEORY AND APPLICATIONS

A large variety of disaggregation methods that have appeared in hydrological literature and used in hydrological applications are reviewed with emphasis in rainfall modelling. The general-purpose stochastic disaggregation models, which have been used at several applications including rainfall modelling but at time scales not finer than monthly, are summarised. The specialised models for rainfall disaggregation, in particular at fine time scales, are examined in more detail. A special disaggregation technique, which, instead of using simultaneously both coarser and finer time scales in one mathematical expression, couples two independent stochastic models, one at each time scale, is further analysed. Two examples of implementing this technique to fine scale rainfall disaggregation are given. In the first case the implementation results in a single variate rainfall disaggregation model (Hyetos) based on the Bartlett-Lewis process. In the second case it results in a multivariate rainfall disaggregation model (MuDRain). These two implementations are demonstrated with results from real world applications. 1