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Temporal stability of effects of the 11-year solar cycle on circulation conditions in central Europe
Paličková, Lea ; Huth, Radan (advisor) ; Halenka, Tomáš (referee)
Temporal stability of effects of the 11-year solar cycle on circulation conditions in central Europe Abstract The aim of this master thesis is to determinewhether circulation conditions in central Europe are affected by variable solar activity. Circulation type classification by Beck (2000) is used here to evaluate the solar effects. Circulation characteristics of circulation are available back to 1780. This master thesis proves that the solar cycle effects on circulation conditions in central Europe are not stationary in time. It was demonstrated that the frequency of individual circulation types varies significantly, depending on the length of studied period. The impact of solar variability on circulation conditions in central Europe is more significant when a shorter time period is being considered. It was also found that the response of circulation characteristics on solar variability is not immediate. There have not been clear results if there exists a linear trend on lagged response of solar variability on circulation characteristics. Linear trend has been found only for a whole year dataset with a lagged response within a year. This thesis proves that the solar cycle effects on troposphere are highly variable, so it is very difficult to define them straightforward. Keywords: atmospheric circulation,...
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Model WRF and its application for regional climate modelling in high resolution
Karlický, Jan ; Halenka, Tomáš (advisor) ; Belda, Michal (referee)
This work is dealing with regional climate models. Firstly, their principle and use of them is described, including advantages and disadvantages of this approach. Further, the application of WRF numerical weather prediction model in climate mode is described and differences in use of CLWRF modification and its advantages for getting results are discussed. Possibilities of this implementation and testing runs for finding appropriate settings are presented. Finally, the results of one ten-year and four five-year simulations of model with different settings are compared with observed values. Some chapters are dedicated to possibilities of processing and graphics outputs of model results and discussion.
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Long-term changes of selected stratospheric fields related to circulation and enhancing greenhouse effect
Kozubek, Michal ; Laštovička, Jan (advisor) ; Halenka, Tomáš (referee)
In the present work we study behavior and trends of stratospheric wind in period of 1957-2002. We used reanalyzed daily data from project ERA-40. Results are shown in graphic form for 3 atmospheric levels. In each level we describe trends of wind velocities and directions separate into 2 seasons. We also compare trends of stratospheric wind with other characteristic indicators of atmospheric circulation. One of them is total columnar ozone and the second is mesopause midlatitude winds. Results of analyze halving adjustment of trends in wind directions and velocities for level 100, 50 and 10 hPa, too.
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Variability of meteorological processes in stratosphere in relation to vertical ozone profile
Motl, Martin ; Kalvová, Jaroslava (advisor) ; Halenka, Tomáš (referee)
There is studied an influence of dynamical processes in atmosphere on the total ozone and its vertical profile in this work. There are described known atmospherical processes with influence on ozone variability and statistical methods used in the work at first. Then is studied connection between ozone and tropopause height. There are also monitored time trends of ozone and tropopauzse height. There are computed modes of variability for the field of the geopotential in pressure levels from 500 to 10 hPa in the next part of the work and there is studied a statistical connection between computed modes and ozone. There is constructed linear regression model from time trend and computed modes. This model describes considerable part of the ozone variability and there are discussed possibilities of use some similar model for prediction of the total ozone in the resume.
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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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Uncertainties in regional climate models outputs
Holtanová, Eva ; Kalvová, Jaroslava (advisor) ; Halenka, Tomáš (referee) ; Dubrovský, Martin (referee)
Title: Uncertainties in regional climate models outputs Author: RNDr. Eva Holtanová Supervisor: doc. RNDr. Jaroslava Kalvová, CSc. Department: Dept. of Meteorology and Environment Protection Faculty of Mathematics and Physics Charles University in Prague Present doctoral thesis focuses on the analysis of uncertainties in regional climate model outputs in the area of the Czech Republic. Generally, the uncertainties in model outputs come from inaccuracies of initial and boundary conditions, further from the necessity to parameterize the small scale processes, and the structure of the model, e.g. the choice of numerical schemes or spatial resolution. In case of the simulations of future climate, another source of uncertainty arises. It is the unknown development of forcings that influence the climate system. The analysis in this work focuses on two multi-model ensembles, that come from two international European projects PRUDENCE and ENSEMBLES. The simulated 30-year mean seasonal air temperature and precipitation amounts are used, for the reference period 1961- 1990, and several future time periods. Two techniques were employed to assess the uncertainties. The first one was aimed at dividing the variance of a multi-model ensemble into contributions of regional model, driving global model and emission...
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The application of atmospheric circulation classifications in the interpretation of climate model outputs
Stryhal, Jan ; Huth, Radan (advisor) ; Halenka, Tomáš (referee) ; Beranová, Romana (referee)
The application of atmospheric circulation classifications in the interpretation of climate model outputs Mgr. Jan Stryhal Automated (computer-assisted) classifications of atmospheric circulation patterns (circulation classifications, for short) constitute a tool widely used in synoptic and dynamic climatology to study atmospheric circulation and its link to various atmospheric, environmental, and societal phenomena. The application of circulation classifications to output of dynamical models of the atmosphere has developed considerably since the pioneering studies about three decades ago, reflecting rapid development in statistics, computing technology, and-naturally-climatological research, increasingly more and more dependent on simulations of the atmosphere, facing the paradigm of anthropogenic climate change. An uncoordinated use of various statistical approaches to analyzing output of global climate models (GCM) or their various ensembles, and an arbitrary selection of circulation variables, spatial and temporal domains, and reference datasets, have contributed to a need for a comparative study, which would shed some light on the sensitivity of studies dealing with an intercomparison of circulation classifications in two datasets to subjective choices. The present thesis responds to this need...
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The application of atmospheric circulation classifications in the interpretation of climate model outputs
Stryhal, Jan ; Huth, Radan (advisor) ; Halenka, Tomáš (referee) ; Beranová, Romana (referee)
The application of atmospheric circulation classifications in the interpretation of climate model outputs Mgr. Jan Stryhal Automated (computer-assisted) classifications of atmospheric circulation patterns (circulation classifications, for short) constitute a tool widely used in synoptic and dynamic climatology to study atmospheric circulation and its link to various atmospheric, environmental, and societal phenomena. The application of circulation classifications to output of dynamical models of the atmosphere has developed considerably since the pioneering studies about three decades ago, reflecting rapid development in statistics, computing technology, and-naturally-climatological research, increasingly more and more dependent on simulations of the atmosphere, facing the paradigm of anthropogenic climate change. An uncoordinated use of various statistical approaches to analyzing output of global climate models (GCM) or their various ensembles, and an arbitrary selection of circulation variables, spatial and temporal domains, and reference datasets, have contributed to a need for a comparative study, which would shed some light on the sensitivity of studies dealing with an intercomparison of circulation classifications in two datasets to subjective choices. The present thesis responds to this need...
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