Articles | Volume 21, issue 2
Hydrol. Earth Syst. Sci., 21, 963–980, 2017
Hydrol. Earth Syst. Sci., 21, 963–980, 2017

Research article 15 Feb 2017

Research article | 15 Feb 2017

Characteristics of rainfall events in regional climate model simulations for the Czech Republic

Vojtěch Svoboda1,2, Martin Hanel1,3, Petr Máca1, and Jan Kyselý1,2 Vojtěch Svoboda et al.
  • 1Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Praha 6 – Suchdol, 165 21, Czech Republic
  • 2Institute of Atmospheric Physics, Czech Academy of Sciences, Boční II 1401, Praha 4 – Spořilov, 141 31, Czech Republic
  • 3T. G. Masaryk Water Research Institute, Podbabská 2582/30, Praha 6 – Dejvice, 160 00, Czech Republic

Abstract. Characteristics of rainfall events in an ensemble of 23 regional climate model (RCM) simulations are evaluated against observed data in the Czech Republic for the period 1981–2000. Individual rainfall events are identified using the concept of minimum inter-event time (MIT) and only heavy events (15 % of events with the largest event depths) during the warm season (May–September) are considered. Inasmuch as an RCM grid box represents a spatial average, the effects of areal averaging of rainfall data on characteristics of events are investigated using the observed data. Rainfall events from the RCM simulations are then compared to those from the at-site and area-average observations. Simulated number of heavy events and seasonal total precipitation due to heavy events are on average represented relatively well despite the higher spatial variation compared to observations. RCM-simulated event depths are comparable to the area-average observations, while event durations are overestimated and other characteristics related to rainfall intensity are significantly underestimated. The differences between RCM-simulated and at-site observed rainfall event characteristics are in general dominated by the biases of the climate models rather than the areal-averaging effect. Most of the rainfall event characteristics in the majority of the RCM simulations show a similar altitude-dependence pattern as in the observed data. The number of heavy events and seasonal total precipitation due to heavy events increase with altitude, and this dependence is captured better by the RCM simulations with higher spatial resolution.

Short summary
The study presents validation of precipitation events as simulated by an ensemble of regional climate models for the Czech Republic. While the number of events per season, seasonal total precipitation due to heavy events and the distribution of rainfall depths are simulated relatively well, event maximum precipitation and event intensity are strongly underestimated. This underestimation cannot be explained by scale mismatch between point observations and area average (climate model simulations).