Sensitivity analysis of extreme precipitation events

Abstract

AbstractA sensitivity analysis of the frequency of extreme precipitation events is performed. Extreme events in the form of total precipitation (e.g. over a month or season) exceeding a relatively large threshold (i.e. extremely wet conditions) or falling below a relatively small threshold (i.e. extremely dry conditions) are treated. To allow for the positive skewness of the distribution of total precipitation, a power transformation to normality is used. The relative sensitivities of extreme precipitation events to the median and to the scale parameter of this distribution are examined. It is shown that these relative sensitivities are both generally greater the more extreme the event. Moreover, the relative sensitivity to the scale is greater than that corresponding to the median for extreme wet events, whereas the opposite is true for extreme dry events. These theoretical results are illustrated through use of a network of precipitation observations in Spain.