A HYBRID MODEL FOR POINT RAINFALL MODELING

A hybrid point rainfall model, a product of two random processes, is p resented. The model uses a jitter model, a general technique for impro ving the fit of any point process based model. We use the nonrandomize d Bartlett-Lewis rectangular pulse and an autoregressive model as a ji tter. First, the five parameters of the Bartlett-Lewis model are estim ated by the method of moments using the mean of one aggregation level and the dry probabilities of all aggregation levels considered. Second , the parameters of the autoregressive model are derived from the mome nts of the historical data and those given by the Bartlett Lewis model , without additional cost in terms of parameter calibration. Using 15- min point rainfall data of Capella, central Queensland, Australia, as a test case, the results of the hybrid model were better than the best results given by the randomized Bartlett-Lewis model. On its own the nonrandomized Bartlett-Lewis model produced very poor results.