资源环境科技发展态势分析平台

To assess the climatology of the Czech Republic (CR) with a high spatial (1km) resolution, this study uses radar-based precipitation data collected over the summer seasons of a 10-year period (2002-2011). Radar reflectivity data were obtained from two C-band Doppler weather radars, integrated in time and merged with daily precipitation totals from rain gauge measurements. Using radar measurements, daily adjusted precipitation totals were later divided into 10-min precipitation totals that were continuously accumulated in a series of time windows ranging from 30min to 24h. This climatological analysis confirms that altitude substantially influences not only the spatial distribution of mean precipitation but also the spatial distribution of precipitation maxima as well as the diurnal cycle of precipitation in the CR. While the 24-h totals are generally maximal in mountains, mean and absolute seasonal maxima of short-term totals (up to 1 and 6h, respectively) are detected in altitudes between 300 and 600m a.s.l. Regarding the diurnal cycle, maximum frequency of precipitation occurs 2h earlier in the mountains, whereas mean totals remain at the same level until 2100 UTC. The mean time during which precipitation maxima occur generally does not change with altitude. Nevertheless, a detailed regional study demonstrates that short-term precipitation maxima usually start earlier in the afternoon in and around mountainous regions. Long-term (mainly 6-h) precipitation maxima occur later than short ones but are substantially less concentrated in time, especially in the mountains. These differences between mountains and lowlands can be explained by smaller relative proportions and earlier onset of convective precipitation in mountains.