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The European summer of 2013 was characterized by very high temperatures that established a new historical maximum in Austria. The extremity of this summer in Europe is assessed based on the E‐OBS and ECA&D data sets. At the continental scale, it is ranked as the fifth warmest summer since 1951, with large positive temperature anomalies over Central Europe. According to seasonal heat wave characteristics, the 2013 summer was unprecedented in Kremsmuenster and Graz (both Austria) and ranked as the second or third at other stations with at least 100 years of measurements in the Czech Republic, Slovakia, Croatia and Slovenia. The most intense 2013 heat wave over Central Europe in early August was driven primarily by anticyclonic conditions and was probably amplified by the preceding precipitation deficit. In combination with major flooding in the Danube and Elbe river basins in early June and severe convective storms at the end of July, the hot 2013 summer in Central Europe may represent an analogue of a future summer climate that will probably be more prone to both temperature and precipitation extremes.

Long-lasting and severe droughts seriously threaten agriculture, ecosystems, and society. Summer 2018 in central Europe was characterized by unusually persistent heat and drought, causing substantial economic losses, and became a part of a several years long dry period observed across this region. This study assesses the magnitude of the recent drought within a long-term context and links the increased drought severity to changes in atmospheric circulation. Temporal variability of drought conditions since the late 19th century was analyzed at seven long-term stations distributed across the Czech Republic using the Palmer Drought Severity Index and the Standardized Precipitation Evaporation Index. The Palmer Z Index and a variation of the Standardized Precipitation Evaporation Index were used to study rapidly emerging short-term droughts and to link these episodes to atmospheric circulation. Changes in circulation were analyzed through circulation types calculated from flow strength, direction and vorticity in mean sea level pressure data from the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis for 1948-2018. Increasing drought severity across the Czech Republic with record-low values of the drought indices during 2015-2018 was found. The trend was distinctive in both vegetation (April-September) and cold (October-March) periods. The tendency toward more severe droughts in recent decades was linked to changes in frequency of dry and wet circulation types, highlighting the important role of atmospheric circulation in regional climate. It remains an open question whether the significantly increasing frequency of dry circulation types in the vegetation period is related to climate change, or rather represents multidecadal climate variability.

Compound climate events in which only one variable is extreme (e.g., either hot but no drought or extreme drought but not hot) and events in which both variables are extreme (e.g., drought and heat waves) may have different impacts on hop yields and alpha-bitter acid contents. Increasing occurrences of compound drought and heat events have led to increased income variability for beer production, and also affecting the major hop growers across Europe (EU). Our study includes the key hop-growing regions across the EU such as Hallertau (Germany); Úštěcko, Žatecko and Tršická (Czech Republic); Kent (Great Britain); Alsace (France); Lublin (Poland); Koroška (Slovenia) and León and Galicia (Spain). For these regions, we used the concurrent bivariate return period to model the joint probability distributions of daily precipitation and maximum temperature extremes and to provide risk assessments for concurrent drought-heat waves during the hop-growing season. We estimated the risk of lower yields from hop cones based on concurrent dry-cool, dry-hot, wet-cool and wet-hot modes over the target areas. The results show that longer and more severe drought and heat wave concurrences have increased more frequently than shorter concurrences. The degree of risk was estimated as being higher over the extensive hop-growing areas in the Czech Republic and Germany. A total of 22.4, 12.5 and 7.2% of EU areas with conditions suitable for commercial hop production fell into the moderate, high and very high yield loss risk categories, respectively. Integrating the damage between April and August indicated that more than 62.7% of total yield losses were due to high temperatures under dry conditions and that 21.5% of the yield losses were due to dry-cool conditions in the top hop-farming regions. The hotter European droughts caused decreases in noble aromatic hops by 29-68%. This indicates that hop yields are very vulnerable to these events due to a slower rate of adaptation of hops compared to field crops. K E Y W O R D S climate-hop yield losses, compound climate events, copula technique, joint return periods

Among the variables that can be employed to characterize agricultural drought, soil drought is of particular importance. This contribution uses gridded soil-drought values calculated from the SoilClim model for the 1961-2019 period to analyse soil drought episodes (based on the 10th percentile) in four lowlands, relatively homogeneous regions in central Europe that provide a longitudinal transect over central Europe. These areas are predominantly located at altitudes of below 400 m asl and include central Bohemia, southern Moravia and an adjacent part of Slovakia, southern Slovakia and eastern Slovakia. The results indicate that, after 1990, such episodes occurred largely in the summer half-year (April-September), accompanied by an increasing linear trend in the 1961-2019 period, while the situation was reversed in the winter half-year (October-March). Selected drought episodes are further divided into three phases (Phase Iorigin, Phase IIcourse, Phase IIIend) and investigated separately in terms of precipitation and objective classification of circulation types based on flow strength, direction and vorticity. Decreases in the frequency of precipitation-rich cyclonic and the directional types associated with higher daily precipitation totals, together with increases in precipitation-poor anticyclonic types, were responsible for soil-drought Phases I and II, with the opposite pertaining to Phase III. Differences in the effects of circulation types on precipitation and soil-drought occurrence were considerable, particularly for central Bohemia compared with the other three regions. The results obtained are also discussed with respect to data uncertainty and their broader spatiotemporal context.