Catastrophic floods in July 1997 and in August 2002 enhanced our interest in heavy precipitation and other meteorological and hydrological extremes. We focus on methods of evaluating the extremity of weather events. Within the GAP209/11/1990 project, we have developed the weather extremity index (WEI) which combines several aspects of extreme events, namely the return periods of the given meteorological element, the size of the affected area and the duration of the event. This allows us to describe the time distribution of weather extremes, especially in terms of their seasonality. A similar weather abnormality index (WAI) is used to assess how extraordinary the event was with respect to the given part of year (Müller a Kašpar, 2014). Our Weather Extremity Calculator allows you to compare the extremity of heavy precipitation events with each other.
The objectively evaluated weather extremes are further studied from various perspectives. We deal mainly with their meteorological causes, using the method of evaluating anomalies in the fields of appropriate dynamic or thermodynamic variables (Kašpar a Müller, 2014). Within the project GA17-23773S, we analyzed the relationship between the extremity of heavy precipitation, their causal conditions and predictability, using a NWP (numerical weather prediction) model. We also pay attention to the influence of meteorological conditions on the occurrence of floods, which is presented in our Atlas of Floods in the Czech Republic. Within the project GA19-05011S in cooperation with the Faculty of Science of Charles University, we focus on the issue of precipitation extremes in mountain areas. We also deal with the simultaneous occurrence of several types of extremes in the so-called compound weather events, on which the project LTC19043 is focused. A comprehensive analysis of weather extremes in Czechia is the goal of our involvement in the recently launched project ME08011 "PERUN".
The above mentioned analytical approaches were applied to weather extremes, especially to heavy precipitation events, at various spatial scales: within the Czech Republic (Müller et al., 2015), in the Vosges Mountains (Minářová et al., 2017a) and the Ore Mountains (Minářová et al., 2017b; Minářová et al., 2018) and within the whole of central Europe (Gvoždíková et al., 2019). For the territory of the Czech Republic and central Europe, we also evaluated the extremity of floods (Müller et al., 2015; Gvoždíková a Müller, 2017) and the relationship of extreme events to moisture flow anomalies (Gvoždíková a Müller, 2021). In addition to heavy precipitation, we similarly dealt with cases of heat (Valeriánová et al., 2017) and windstorms in the Czech Republic (Kašpar et al., 2017).