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The influence of long-term changes of atmospheric circulation on observed trends of surface climatic elements in the Czech Republic and Europe
Cahynová, Monika ; Huth, Radan (advisor) ; Metelka, Ladislav (referee) ; Halenka, Tomáš (referee)
(English) RNDr. Monika Cahynová: The influence of long-term changes of atmospheric circulation on observed trends of surface climatic elements in the Czech Republic and Europe The aim of this thesis is to quantify the links between recent atmospheric circulation changes over Europe and local surface climatic trends. We employ several parallel classifications of circulation types that were collected and developed within the COST733 Action "Harmonisation and Applications of Weather Types Classifications for European Regions". To our knowledge, such a comparative approach has not been used so far. Atmospheric circulation changes over Europe were studied in terms of changing seasonal frequency and persistence of daily circulation types in the second half of the 20th century. The extensive collection of both subjective and objective catalogues of circulation types in European regions from the COST733 Action served as a platform for comparison of different classification methods, varying numbers of circulation types, and spatial scale of circulation processes. The most prominent trend - winter increase in the number of days with westerly flow - clearly stems from the strengthening of the North Atlantic Oscillation. The objective classifications did not show any systematic change of persistence of...
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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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Coupling atmospheric chemistry/aerosols to regional climate models
Huszár, Peter ; Halenka, Tomáš (advisor) ; Macoun, Jan (referee) ; Eben, Kryštof (referee)
Title: Coupling atmospheric chemistry/aerosols to regional climate models Author: Peter Huszár Department: Department of Meteorology and Environment Protection Supervisor: doc. RNDr. Tomáš Halenka, CSc. Supervisor's e-mail address: tomas.halenka@mff.cuni.cz Abstract: In this thesis, the connections between air quality and climate are studied. For this purpose, regional climate model RegCM3 and chemistry transport model CAMx has been coupled offline with one- and two-way interaction. Our work represents a first attempt to connect RegCM3 not only with CAMx, but with any other chemistry transport model. As a first step, an offline one way couple of RegCM3 and CAMx has been developed, meaning that the climate model drives the transport, emission, chemical transformation and deposition of species while the radiative feedbacks of gases and aerosols are not considered. A meteorological interface has been developed at our department in order to convert the meteorological data generated by RegCM3 to fields required by CAMx. For those parameters that are essential for CAMx but the regional climate model does not supply them, diagnostic methods were implemented into this interface. Further, it is used to calculate biogenic emissions. Regarding anthropogenic emissions, a simple utility has been developed to...
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Long term variability of the relationshops between atmospheric circulation and surface climate elemets
Beranová, Romana ; Huth, Radan (advisor) ; Halenka, Tomáš (referee) ; Metelka, Ladislav (referee)
The stability of the relationships between atmospheric circulation and the surface climatic variables is an important precondition to construct scenarios of climate change by statistical methods. The aim of the work is therefore to examine if and how the relationships between atmospheric circulation (characterized by geopotenial heights of 500 hPa level) and surface climatic elements (mainly temperature and precipitation) are changing in European region and in the Czech Republic. The relationship between the NAO index and both temperature and precipitation were analysed for long period (1901-99) at 29 resp. 27 European stations. The NAO index strong influences climate in Europe. However, the relationships were changing in time. The course of 31-years running correlation differs between different European regions and different seasons. The circulation modes were identified in geopotential heights of 500 hPa level by rotated principal component analysis for period 1958-98. The climate in Europe is influenced by NAO, EA, EU1, EU2 and NA mode. The variability of the relationships was represented by 15-year running correlations at more than 100 European stations. The regions with similar courses of running correlations were identified by cluster analysis (PAM method). Despite the considerable variability of the...
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Analysis of the outputs of high-resolution regional climate models
Kvasničák, Josef ; Mikšovský, Jiří (advisor) ; Halenka, Tomáš (referee)
This thesis studies the outputs of selected regional climate models used in the ENSEMBLES and CECILIA projects. The analysis is concerned with outputs for the region of central Europe, using selected temperature and precipitation characteristics. The thesis starts with summarizing the basic knowledge about mathematical modeling of the climate. Special attention is then focused on validation of simulations outputs for period 1961-1990. Furthermore, signals of changes in the selected climate characteristics are examined for the periods 2021-2050 and 2071-2100. In the period 2021-2050 the rising of average air temperature typically by 1 řC is observed, simulated changes in precipitations is not distinctive. In the period 2071-2100 the rising of air temperature typically by 4 řC and changes in the precipitations totals up to 40 % are observed, nevertheless the inter-simulation variability is significant, the spatial variability as well.
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Changes in occurrence of climate types in the simulations of future climate
Mejsnar, Jan ; Mikšovský, Jiří (advisor) ; Halenka, Tomáš (referee)
The thesis compares climate classification of the Czech Republic based on two regional climate models (ALADIN-Climate and RegCM3) and on two model period (1961-1990 and 2021-2050). First, a short summary of climate classifications suitable for the Czech Republic is introduced. Above all are mentioned the classifications of Köppen, Kurpelová and Konček. The advantages of these classification are presented, especially their relation to occurrence of vegetation. Further, this thesis mentions today's regional climate models. The data of monthly values of precipitation and temperature were analysed by single classifications criteria and consequently visualized by the program SURFER to show individual climatic subtypes. The data represented averaged values for the periods 1961-1990 and 2021-2050. Finally the distribution and the veracity of both models are discussed.
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Long-term changes of selected stratospheric fields related to circulation and enhancing greenhouse effect
Kozubek, Michal ; Halenka, Tomáš (referee) ; Laštovička, Jan (advisor)
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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