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A renewal cluster model for the inter-arrival times of rainfall events

✍ Scribed by Paul S.P. Cowpertwait


Publisher
John Wiley and Sons
Year
2001
Tongue
English
Weight
286 KB
Volume
21
Category
Article
ISSN
0899-8418

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✦ Synopsis


Abstract

A statistical model, based on a renewal cluster point process, is proposed and used to infer the distributional properties of dry periods in a continuous‐time record. The model incorporates a mixed probability distribution in which inter‐arrival times are classified into two distinct types, representing cyclonic and anticyclonic weather. This results in rainfall events being clustered in time, and enables objective probabilistic statements to be made about storm properties, e.g. the expected number of events in a storm cluster. The model is fitted to data taken from a gauge near Wellington, New Zealand, by maximizing the likelihood function with respect to the parameters. The Akaike Information Criteria is used to select the best fitting distributions from a range of candidates. The Log‐Normal distribution is found to provide the best fit to the times between successive storm clusters, whilst the Weibull distribution is found to provide the best fit to the times between successive events in the same storm cluster. Harmonic curves are used to provide a parsimonious parameterization, allowing for the seasonal variation in precipitation. Under the fitted model, the interval series is transformed into a residual series, which is assessed to determine overall goodness‐of‐fit. Copyright © 2001 Royal Meteorological Society