AGGREGATION-DISAGGREGATION PROPERTIES OF A STOCHASTIC RAINFALL MODEL

A statistical approach based on the modified Bartlett-Lewis rectangula r pulses model is presented to disaggregate rainfall statistics from d aily data. Six model parameters are estimated from 24- and 48-hour acc umulated rainfall data. Based on these estimated parameters, in additi on to reproducing 24- and 48-hour statistics, the model is shown to in fer 1-, 2-, 6-, and 12-hour historical statistics satisfactorily. An u pper limit for disaggregation scale (about 2 days) for this model has been identified. This characteristic behavior of the model is related to the power law dependence of the power spectrum for timescales small er than 2 days. A detailed comparison between observed and modeled sta tistics of rainfall data is presented for two rain gages, one from cen tral Italy and the other from the midwestern United States.