Non-Parametric Statistics on Extreme Rainfall

Abstract

This article focuses on rain as input data to problems related to urban storm drainage. The rain data originate from a monitoring program consisting of 56 gauges in Denmark. The gauges have observation periods ranging from 2 to 14 years. The gauges sample rain in a quantity of 0.2 mm with a resolution in time of 1 minute. Two variables have been investigated: peak intensity and depth. Design values for return periods in the range from 0.1 to 2 years have been estimated for each gauge separately by means of the bootstrap resampling method. The estimation includes expected value, standard deviation and confidence intervals of the design value. For large return periods the uncertainty of the estimates prevents a distinction by gauge between different statistical populations. However, for small return periods a test shows significant variation between gauges, i.e. the uncertainty of the estimates may not be assumed to be due to sampling variability only.