Temporal and spatial variability of spring precipitation in the Czech Republic

Spring precipitation is a key factor determining vegetation growth and strongly affecting soil moisture in spring and summer. Whilst winter precipitation and snow cover as well as summer convective precipitation are frequently researched, only little attention is given to spring precipitation and its temporal variation.

In this contribution we focus on March, April and May daily precipitation at 72 station in the Czechia over 1980-2016. The temporal and spatial variability of precipitation totals, number of wet and dry days and periods is discussed in detail. The altitudes of the stations range from 158 to 1302 m a. s. l. and the mean spring precipitation totals vary from 104 to 327 mm. The highest mean number of dry days (more than 70) is reached at four stations elevated from 241 to 474 m a. s. l.  whilst the lowest number (less than 54) occurs at two stations above 1 km but also at one station in 740 m a. s. l. The duration of severe dry spells is not linked to altitude, either. The longest 43-days dry spell occurred at almost all stations up to 880 m a. s. l. No common trend of precipitation totals as well as dry or wet days exists over the area in studied period.

The analysis indicate that spring precipitation characteristics are rather related to surrounding and position of station with regard to prevailing flow direction than altitude. The hierarchical cluster analysis based on seasonal and monthly precipitation totals, number of wet and dry days, number and duration of wet and dry periods, trends of wet and dry days number and several other characteristics separated individual stations into 4 groups. Except the groups of lowland dry and mountain wet stations, the group associated low elevated wet stations on windward mountain sides and the other one with high elevated dry stations were created.