Return values of 60-minute extreme rainfall for Hungary

The rainfall intensity for various return periods are commonly used for hydrological design. In this study, we focus on rare, short-term, 60-minute precipitation extremes and related return values which are one of the relevant durations in the planning and operating demands of drainage and sewerage systems in Hungary. Time series of 60-minute yearly maxima were analyzed at 96 meteorological stations. To estimate the return values for a given return period, the General Extreme Value (GEV) distribution was fit to the yearly maxima. The GEV fit and also the Gumbel fit (GEV Type I.) were tested. According to the goodness of fit test results, both GEV and Gumbel distributions, are adequate choices. The return values for 2, 4, 5, 10, 20, and 50 year return periods are illustrated on maps, and together with their 95% confidence intervals, are listed in tables for selected stations. The maps of return values demonstrate that the spatial patterns of the return values are similar, although the enhancing effect of orography can be explored in the Transdanubia region and in the North Hungarian Range. As the return period is increasing, so the range of the confidence are widening as it is expected

Changes of Temperature and Precipitation Extremes following Homogenization

Climate indices to detect changes have been defined in several international projects on climate change. Climate index calculations require at least daily resolution of time series without inhomogeneities, such as transfer of stations, changes in observation practice. In many cases the characteristics of the estimated linear trends, calculated from the original and from the homogenized time series are significantly different. The ECA&D (European Climate Assessment & Dataset) indices and some other special temperature and precipitation indices of own development were applied to the Climate Database of the Hungarian Meteorological Service. Long term daily maximum, minimum and daily mean temperature data series and daily precipitation sums were examined. The climate index calculation processes were tested on original observations and on homogenized daily data for temperature; in the case of precipitation a complementation process was performed to fill in the gaps of missing data. Experiences of comparing the climate index calculation results, based on original and complemented-homogenized data, are reported in this paper. We present the preliminary result of climate index calculations also on gridded (interpolated) daily data