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Singularities in annual cycle of climatic variables, their long-term changes and relationships to atmospheric circulation
Radová, Michaela ; Kyselý, Jan (advisor) ; Kalvová, Jaroslava (referee)
In this thesis a statistical detection of singularities (strong deviations from the smoothed mean annual cycle of a climatic variable) was performed on the basis of mean daily air temperature at the Prague - Klementinum station over the period 1881-2000. A temporal stability of all singularities was investigated, and probabilities of the occurrence of the strongest ones and some of the most often mentioned ones were determined. Long-term changes of occurrence of these singularities and their relationships to atmospheric circulation were analyzed. The results show that the temporal stability (annual recurrence as well as regular occurrence at specific calendar days of a year) cannot be assumed for most singularities. Moreover, some of the singularities found using this procedure can generally be just statistical properties of a chosen sampling without relationships e.g. to circulation conditions. That is why it is not proper to look for singularities tied closely to a specific date and use only one reference period for their detection. Variability of atmospheric circulation is the main source of long-term changes of the occurrence of examined singularities.
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Heat waves over Central Europe in ALADIN-Climate/CZ regional climate model: evaluation and future projections
Lhotka, Ondřej ; Farda, A. ; Kyselý, Jan
We evaluated a simulation of Central European heat waves and analysed possible changes of their characteristics in the future climate using the ALADIN-Climate/CZ regional climate model with 25km horizontal grid spacing. Lateral boundary conditions were provided by the ARPEGE global climate model, using historical forcing and the SRES A1B scenario. Observed data were taken from the E-OBS gridded data set. Heat waves were evaluated over 1970−1999 and changes in their characteristics were assessed for 2020−2049. Their definition is based on exceedance of the 90th percentile of summer daily maximum temperature calculated separately for modelled and observed data. ALADIN-Climate/CZ simulates characteristics for the recent climate quite well, especially the overall severity of heat waves. In contrast, temperature amplitude was considerably overestimated. This model projects an increase in overall heat wave severity by a factor of 2 to 3 in the future climate, primarily driven by an increasing number of events. The study shows that ALADIN-Climate/CZ is generally capable of simulating Central European heat waves, which gives more credibility to model projections of future heat waves.
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Methods for estimation of extreme precipitation and their applications in the Czech Republic
Picek, J. ; Kyselý, Jan ; Gaál, Ladislav
The paper summarizes concepts and methods applied in estimation of probabilities of extreme precipitation amounts and design precipitation in the Czech Republic in the recent past. This work was motivated by the occurrence of several extraordinary precipitation events that resulted in floods with enormous material damages, but also by advances in the field of statistical modelling of extremes. The methods that we introduce are split in two main parts: methods for estimation of probable maximum precipitation and methods for estimation of design precipitation using different variants of the regional frequency analysis. In the concluding section several open issues and possible directions of follow-up research and improvements are outlined.
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Analysis of temporal variability and spatial characteristics of heat waves in central Europe using extremity index
Lhotka, Ondřej ; Kyselý, Jan
Heat waves have severe consequences on natural environment and society. Th e majority of studies defined heat waves from station data only, so there is a need to examine these events not only from the aspect of point characteristics of air temperature and duration, but also from the view of their spatial extent. In this study, heat waves over Central Europe were analysed using the gridded E-OBS dataset. Th e extremity index of heat waves, which takes into account their spatial extent, duration, and peak temperature, was proposed and used to analyse variability of heat waves over Central Europe from 1950 to present. We delimited 220 hot days and 21 heat waves and computed the extremity index for each heat wave. Th e eight most signifi cant heat waves based on the extremity index were visualized. Temporal variability of hot days and heat waves was analysed and we demonstrate that the number of hot days and the severity of heat waves have been increasing.
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Klimatická změna a klimatické fluktuace - normály vybraných klimatologických prvků na území České republiky: Výzkum dopadů klimatické změny vyvolané zesílením skleníkového efektu na sektory vodních zdrojů, zemědělství, lesního hospodářství a zdravotnictví. Možné vlivy klimatické změny na lidské zdraví
Český hydrometeorologický ústav, Praha ; Univerzita Karlova v Praze, Matematicko-fyzikální fakulta ; Národní klimatický program České republiky ; Květoň, Vít ; Kyselý, Jan ; Kazmarová, Helena
Cílem úkolu bylo, v návaznosti na předchozí i paralelně realizovaný výzkum, zvětšit rozsah vyhodnocení možných efektů předpokládaných klimatických změn na zdraví lidí v ČR. Zdravotní důsledky globálních klimatických změn a úbytku ozónu ve stratosféře (přímé a nepřímé účinky). Přehled dopadů změny klimatu na lidské zdraví: Přímé vlivy - horké vlny a další klimatické extrémy (záplavy, sucha, tropické cyklóny apod.), nepřímé vlivy (kvalita ovzduší a infekční nemoci), adaptační opatření, dopady změny klimatu na zdraví významné pro Evropu (scénáře změny klimatu pro Evropu, hlavní oblasti dopadů změny klimatu na lidské zdraví v Evropě, stres z horka, kvalita ovzduší, nemoci šířící se přenašeči, nemoci vázané na vodu, zdravotní důsledky povodní). Potřeba výzkumu dopadů změn klimatu na lidské zdraví. Rostlinné pyly a pylové alergie (alergická onemocnění, rostlinné pyly v ovzduší, ovlivnění pylové situace v Praze vybranými meteoparametry). Výjezdy zdravotnické záchranné služby (data o ošetřených pacientech, meteorologická data, statistická analýza a deskripce dat).
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The heat-stress-related mortality in the Czech Republic: first results
Kyselý, Jan ; Huth, Radan ; Kříž, B.
The analysis of the HSR mortality in the Czech Republic tries to find answers to the following questions: (i) which treshold value of tempereture (or of another temperature- and humidity- related variable)must be exceeded to observe the HSR mortality, in dependence on time of the year; (ii) which meteorological variable (or an index) accounts for the largest portion of the mortality increase, and what is the best model between meteorological variables and mortality; (iii) what is the dependence of the HSR mortality on the age group and sex; and (iv) whether a synoptic approach based on an objective classification of air masses leads to better results compared to the more traditional methods. The analysis covers the 1990s when some extremely hot summers appeared in the Czech Republic.
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