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Spatial patterns of links between temperature extremes and cardiovascular mortality in the Czech Republic
Urban, Aleš ; Kyselý, Jan (advisor) ; Huth, Radan (referee) ; Dobrovolný, Petr (referee)
Name of the thesis: Spatial patterns of links between temperature extremes and cardiovascular mortality in the Czech Republic Author: Mgr. Aleš Urban Previous studies have examined relationships of high and low air temperatures to mortality due to cardiovascular diseases (CVDs) in the Czech Republic as a whole. Much less has been understood about possible regional differences in the heat and cold effects on mortality. Within four papers published in international peer-reviewed journals, the author of this thesis investigated links between extreme temperatures and CVD mortality in the Czech Republic while considering in particular differences between (i) urban and rural areas, (ii) regions with different socioeconomic status, and (iii) regions with different physical-environmental conditions. Various biometeorological approaches were compared in order to identify meteorological characteristics affecting heat- and cold-related mortality. Excess mortality was determined as differences between observed and expected daily values, the latter being adjusted for long-term changes, annual and weekly cycles, and epidemics of influenza/acute respiratory infections. Air temperature, biometeorological indices (including the Universal Thermal Climate Index, Apparent Temperature, and Physiologically Equivalent...
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Changes in selected characteristics of precipitation from convective and stratiform cloudiness
Rulfová, Zuzana ; Kyselý, Jan (advisor) ; Bednář, Jan (referee)
Significant trends in some characteristics of atmospheric precipitation have been observed in central Europe in recent decades. Little attention has been paid to the investigation whether these trends are related to changes of precipitation falling from v convective and stratiform cloudiness. This thesis deals with disaggregation of precipitation into convective and stratiform on the basis of the database of 10 SYNOP stations in the Czech Republic. The differentiated precipitation amounts were analyzed with respect to trends of total and heavy rainfall in individual seasons for the period 1982-2005. For convective precipitation in the western part of the Czech Republic, the observed trend is increasing in total precipitation, except for spring, and declining in heavy rainfall, except for fall and winter. In the eastern part of the Czech Republic, the total amounts are increasing (except for winter) and heavy rainfall is decreasing, except for spring. For stratiform precipitation, the growing trend prevails in all the characteristics of the total and heavy rainfall throughout the Czech Republic. The exception is the spring season with the downward trend.
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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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Links between atmospheric circulation and surface air temperature distributions in climate models
Pejchová Plavcová, Eva ; Kyselý, Jan (advisor) ; Halenka, Tomáš (referee) ; Huth, Radan (referee)
Title: Links between atmospheric circulation and surface air temperature distributions in climate models Abstract: This thesis comprises a collection of five papers dealing with validation of regional climate model (RCM) simulations over Central Europe. The first paper illustrates and discusses problems with observed data that are used for model validation and how the choice of reference dataset affects the outcomes in validating the RCMs' performances. The second paper evaluates daily temperatures, and it indicates that some temperature biases may be related to deficiencies in the simulations of large- scale atmospheric circulation. RCMs' ability to simulate atmospheric circulation and the observed links between circulation and surface air temperatures are examined in detail in the third paper. This article also compares performances of individual RCMs with respect to the driving data by analysing the results for the driving data themselves. The fourth paper focuses on biases in the diurnal temperature range within RCMs and their possible causes by examining links of the errors to the at- mospheric circulation and cloud amount. The last paper investigates the observed relationships between atmospheric circulation and daily precipitation amounts over three regions in the Czech Republic, as well as how these...
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Effects of temperature extremes on hospital admissions for cardiovascular diseases
Urban, Aleš ; Kyselý, Jan (advisor) ; Huth, Radan (referee)
Faculty of Sicence, Charles University Aleš Urban, Praha 2012 Effects of temperature extremes on hospital admissions for cardiovascular diseases The thesis compares differences in the impacts of warm and cold days on both excess mortality and hospitalizations for individual cardiovascular diseases (CVDs) in Prague and a selected rural region (southern Bohemia - JČ) consisting of the Jihočeský kraj and Vysočina districts in the period 1994- 2009. Population size and age structure are similar in the two regions. The differences are compared between selected population groups (men and women; < 65 and 65+ years). Value of the 90% (10%) percentile of daily mean air temperature in summer (winter) during the period were used for the definition of warm (cold) days for each region separately. The excess mortality and hospitalizations were determined as the difference from standardized daily counts of death and hospital admissions, adjusted for the epidemics of influenza/acute respiratory infections, and for annual and weekly cycles of mortality and hospitalizations. In Prague on warm days, we observed a significant (p = 0.05) excess mortality for CVD as a whole as well as for individual diagnoses, in more population groups than in the JČ region. The highest relative excess mortality on warm days in Prague was...
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Frequency analysis of precipitation amounts
Rulfová, Zuzana ; Kyselý, Jan (advisor) ; Holtanová, Eva (referee) ; Picek, Jan (referee)
Title: Frequency analysis of precipitation amounts Author: Mgr. Zuzana Rulfová Department: Department of Atmospheric Physics Supervisor: RNDr. Jan Kyselý, Ph.D., Institute of Atmospheric Physics CAS Abstract: This thesis deals with analysing characteristics of mean and extreme precipitation in observations and regional climate models (RCMs) with respect to their convective and stratiform origin. An algorithm for subdivision of precipitation amounts into predominantly convective and stratiform using station weather data is proposed and evaluated. The time series of convective and stratiform precipitation from the Czech Republic over 1982-2010 are used for analysing basic climatological characteristics of precipitation, including extremes, and evaluating RCMs from the ENSEMBLES project. Projected changes of convective and stratiform precipitation in Central Europe (the Czech Republic) are analysed using data from RCM simulations from the EURO-CORDEX project. The last part of the thesis introduces a new statistical model for analysing precipitation extremes. This model takes advantage from knowledge of origin of precipitation extremes. In future climate we could expect more convective and stratiform precipitation amounts in all seasons except summer, when climate models project decline in amounts of stratiform...
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Frequency analysis of precipitation amounts
Rulfová, Zuzana ; Kyselý, Jan (advisor)
Title: Frequency analysis of precipitation amounts Author: Mgr. Zuzana Rulfová Department: Department of Atmospheric Physics Supervisor: RNDr. Jan Kyselý, Ph.D., Institute of Atmospheric Physics CAS Abstract: This thesis deals with analysing characteristics of mean and extreme precipitation in observations and regional climate models (RCMs) with respect to their convective and stratiform origin. An algorithm for subdivision of precipitation amounts into predominantly convective and stratiform using station weather data is proposed and evaluated. The time series of convective and stratiform precipitation from the Czech Republic over 1982-2010 are used for analysing basic climatological characteristics of precipitation, including extremes, and evaluating RCMs from the ENSEMBLES project. Projected changes of convective and stratiform precipitation in Central Europe (the Czech Republic) are analysed using data from RCM simulations from the EURO-CORDEX project. The last part of the thesis introduces a new statistical model for analysing precipitation extremes. This model takes advantage from knowledge of origin of precipitation extremes. In future climate we could expect more convective and stratiform precipitation amounts in all seasons except summer, when climate models project decline in amounts of stratiform...
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Frequency analysis of precipitation amounts
Rulfová, Zuzana ; Kyselý, Jan (advisor)
Title: Frequency analysis of precipitation amounts Author: Mgr. Zuzana Rulfová Department: Department of Atmospheric Physics Supervisor: RNDr. Jan Kyselý, Ph.D., Institute of Atmospheric Physics CAS Abstract: This thesis deals with analysing characteristics of mean and extreme precipitation in observations and regional climate models (RCMs) with respect to their convective and stratiform origin. An algorithm for subdivision of precipitation amounts into predominantly convective and stratiform using station weather data is proposed and evaluated. The time series of convective and stratiform precipitation from the Czech Republic over 1982-2010 are used for analysing basic climatological characteristics of precipitation, including extremes, and evaluating RCMs from the ENSEMBLES project. Projected changes of convective and stratiform precipitation in Central Europe (the Czech Republic) are analysed using data from RCM simulations from the EURO-CORDEX project. The last part of the thesis introduces a new statistical model for analysing precipitation extremes. This model takes advantage from knowledge of origin of precipitation extremes. In future climate we could expect more convective and stratiform precipitation amounts in all seasons except summer, when climate models project decline in amounts of stratiform...
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Long-term variability of heat waves and cold spells in Central Europe
Lhotka, Ondřej ; Kyselý, Jan (advisor) ; Halenka, Tomáš (referee) ; Huth, Radan (referee)
Title: Long-term variability of heat waves and cold spells in Central Europe Author: Mgr. Ondřej Lhotka Department: Department of Physical Geography and Geoecology, Faculty of Science, Charles University in Prague Supervisor: RNDr. Jan Kyselý, Ph.D., Institute of Atmospheric Physics, Czech Academy of Sciences Abstract: Heat waves and cold spells have serious impacts on natural environment and society. The main aims of this thesis are to examine past variability of Central European heat waves and cold spells, to assess severity of recent events in a long-term context, to evaluate simulation of heat waves in climate models, and to construct their scenarios for a possible future climate. Heat waves and cold spells were primarily investigated as spatial events, using gridded data sets. E-OBS gridded data was utilized to assess past variability of heat waves and cold spells and to evaluate regional climate model (RCM) simulations from the ENSEMBLES and EURO-CORDEX projects. An extremity index that captures joint effects of temperature, duration, and spatial extent of individual heat waves and cold spells was proposed and tested. The persistent 1994 heat wave was found to be the most extreme over Central Europe in the 1950−2012 period, and the summer of 2013 was unprecedented at several Central European stations...
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