• Energy Research

A first-time common cross-border assessment of observed climatic changes in the Saxon–Bohemian region was the aim of the German–Czech climate cooperation INTERKLIM. This paper focuses on the observed changes of temperature and precipitation averages and extremes within the period 1961–2010, investigating how variations of a range of climate indices were regionally shaped by changes in frequency and character of weather types. This investigation serves to enhance our understanding of the regional climate characteristics to develop transboundary adaptation strategies and focuses on the classification of the “Grosswetterlagen” using the parameters of air temperature and precipitation. Climate data were quality controlled and homogenized by a wide range of methods using the ProClimDB software with a subsequent comprehensive regional visualization based on Geographical Information Systems. Trends for the temperature averages showed increasing trend values mainly from January to August, especially for high temperature extremes. Precipitation trends displayed regionally varying signals, but a strong spatially uniform decrease from April to June (early growing season) and a distinctive increase from July to September (late growing season). Climatic changes were supported by frequency changes of weather types, e.g., the drying from April to June was related to a decrease/increase in patterns causing rather wet/dry conditions, while from July to September opposite trends were observed. Our results represent regional climatic changes in a complex topography and their dependency on variations in atmospheric circulation peculiarities.

Recent drought and a surge in days with weather conditions conducive to wildfire occurrence during 2015-2019 reminded the Czech Republic that it is not immune to this type of natural hazard. Although Central Europe has not been at the center of such events, observed climate data and climate projections suggest a tendency toward more years with wet and mild winters and dry and hot summers. To fill the existing knowledge gap, we used an ensemble of 9 fuel aridity metrics, including 3 dedicated fire weather indices, and evaluated their level of agreement with actual fire occurrence and their temporal trends. The analysis included peri-urban zones of the 36 largest cities and towns in the Czech Republic (home of 3.8 million inhabitants) and the 29 largest protected areas (covering 13.7% of the territory). Fire weather climatology, based on both the Fire Weather Index and the Forest Fire Danger Index, agreed well with the long-term frequency of fires both in peri-urban zones and within protected areas. Future projections based on regional and global model ensembles indicated a significant increase in fuel aridity and an increase in the area affected by fire-conducive conditions both around urban areas and within protected regions. In particular, the area affected by days with very high risk fire weather conditions is likely to increase significantly relative to the past 60 yr. However, the magnitude of the projected change depends to a large degree on the selected fire weather metric and whether RCM- or GCM-based scenarios are used.

Study Region: : The Thaya river basin provides multiple water uses in the transboundary region of Lower Austria and Southern Moravia. Due to the low precipitation (P) to reference evapotranspiration (ETo) ratio, the Thaya river basin is among the most sensitive to climate change in the region. Study Focus: : The main objective is to understand the changes in the water balance variables including actual evapotranspiration (ET), P and runoff (RO) and their drivers for the period 1981–2020, and 2001–2020 in the case of using remote sensing data. New Hydrological Insights for the Region: : The analyses confirm previously reported increasing trends in air temperature, ETo, and no trends in P. ET consistently increased during spring and decreased during summer, although insignificantly. This change was associated with a significant increase of spring vegetation development followed by summer stagnation. The spring RO shows significantly decreasing trends, especially in the upland water source areas. The correlation analysis reveals a different behavior along the altitude gradient, with ET in the uplands generally limited by available energy whilst in the lowlands by available water in spring. In summer, however, the entire basin is often water-limited, with a more pronounced limitation in the lowlands. Complex adaption measures reflecting the different hydroclimate relations across the altitudinal gradient are needed to sustain the water dependent sectors operating in the region facing increasing aridity.

Cities are complex socioecological systems that are particularly vulnerable to the impacts of climate change and are also exposed to other trends, such as urbanization and population aging. Due to the changing climate, days with extreme temperatures are expected to become more numerous, which is particularly important for urban areas, where the urban heat island phenomenon is observed. This study presents an example of a spatially explicit potential climate change impact assessment of heatwaves integrating both science and stakeholder participation for three large Czech cities (Prague, Brno, and Pilsen). Stakeholder participation exercises were used to prioritize climate change risks, provide impetus and opportunity for knowledge co-production, and support adaptation planning. Potential climate change impacts of heatwaves in the three Czech cities for the current baseline (1981–2010) and for the future (2021–2040) using Representative Concentration Pathways (RCPs)—RCP 4.5 and RCP 8.5, were mapped at two levels describing “in-city” and “inter-city” comparison. When comparing the potential impact of heatwaves across the three cities (“inter-city”), the most affected city is Brno, with 10.5% of its area in the very high impact category for the baseline and both RCPs. The “in-city” comparison shows the differences between the baseline and future scenarios of each city. The assessment of heatwaves’ impacts was further used to support urban adaptation planning.

The presented work complements studies on agroclimatic zoning that were performed during 19th and 20th century in the Czech Republic and Austria and allows estimating the effect of climate change on the spatial distribution of agroclimatic conditions within both countries. The main conclusions of the study are: (1) The combination of increased air temperature and changes in the amount and distribution of precipitation will lead to significant shifts in the agroclimatic zones by the 2020's. The current most productive areas will be reduced and replaced by warmer but drier conditions, which are considered less suitable for rainfed farming. (2) While trends in the changes expected in lowlands are mostly negative (especially for non-irrigated crops), higher elevations might experience improvement in their agroclimatic production potential. However, the production potential of these regions is usually limited by other factors such as the soil quality and terrain accessibility. Additionally, these positive effects might be shortlived, as by the 2050's, even the areas in higher altitudes might experience much drier conditions than nowadays. (3) Dairy-oriented agriculture (based on permanent grassland production) at higher altitudes could suffer through an increased evapotranspiration demand combined with a decrease in precipitation, leading to higher water deficits and yield variations. (4) All above listed changes will most likely occur within less than four decades. The rate of change might be so high that the concept of agroclimatic zoning itself might lose its relevance due to the perpetual change.

To construct time series for a Fire Weather Index (FWI), input weather series may come from various sources [...]

The present study yields detail validation of the pest occurrence models under current climate in wide European domain. Study organisms involve Cydia pomonella, Lobesia botrana, Ostrinia nubilalis, Leptinotarsa decemlineata, Oulema melanopus, Rhopalosiphum padi, and Sitobion avenae. Method used in this study belongs to the category climate matching (CLIMEX model) allowing the estimation of areas climatically favourable for species persistence based on the climatic parameters characterising the species development. In the process of model validation parameters were iteratively tested and altered to truly describe the pest presence. The modelled pests presence was verified by comparison of the observed pests occurrence with the number of generations in given modelled area. The notable component of the model parameterization was the sensitivity analyses testing the reaction of species development on changing meteorological items. Parameterization of the factors causing distribution patterns of study species was successful and modelled potential distributions of species correspond well to known core distribution areas for all of these species. This validation study is intended as an initial for forthcoming studies focused on the estimation of geographical shifts of selected pests in the conditions of climate change within the Europe.

The paper shows a large-scale shift in agroclimatic zones in the territory of the Czech Republic (CR) between 1961 and 2019. The method used for agroclimatic zoning took advantage of high-resolution (0.5 km × 0.5 km) daily climate data collected from 268 climatological and 787 rain-gauge stations. The climate information was combined with soil and terrain data at the same resolution. The set of seven agroclimatic indicators allowed us to estimate rates of changes in agroclimatic conditions over the 1961-2019 period, including changes in the air temperature regime, global radiation, drought, frost risks and snow cover occurrence. These indicators are relevant for all main crops and agroclimatic zoning and account for local soil and slope conditions. The study clearly highlights major shifts in the type and extent of agroclimatic zones between 1961-2000 and 2000-2019, which led to the occurrence of entirely new combinations of agroclimatic indicators.