Areal distribution and precipitation–altitude relationship of heavy short-term precipitation in the Czech Republic in the warm part of the year

Abstract

The article presents an analysis of heavy short-term precipitation for the warm part of the year in the Czech Republic (CR). Precipitation data are prepared for the years 2002–2007 with a horizontal resolution of 1 km and a temporal resolution of 1 h. A method merging radar and daily rain gauge measurements is applied to calculate basic hourly precipitation. Two types of 1-, 2-, 3-, and 6-h precipitation data, derived from the basic hourly precipitation, are investigated from the viewpoint of precipitation–altitude relationships and areal distributions of heavy precipitation. The first type of data consists of sums of hourly precipitation, where the summation is performed for all data regardless of whether the summed hourly precipitation is a part of a longer precipitation event or if some hours are without precipitation. The second type of data contains temporally bounded precipitation events. This type predominantly includes convective precipitation. The results show that for both types of data, 1-h precipitation with high rain rates is without apparent dependence on altitude. For the first type of data and for precipitation durations of 2 and 3 h, the impact of altitude on precipitation maps can be identified for low and high rain rates. The impact of mountains is evident for the 6-h precipitation because it includes large scale precipitation events. However, the second type of data does not depend on altitude for heavy precipitation. Heavy precipitation of the second type shows, especially for 6-h, an increased frequency of occurrence in the south to central CR.