Changes of Temperature and Precipitation Extremes following Homogenization

Abstract

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.