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Characteristics of convective environment in ALADIN reanalysis
Zacharov, Petr, jr. ; Vokoun, Martin
For the prediction and assessment of the potential for convective cloud formation, various characteristics of the convective environment are used. Values of CAPE, CIN, wind speed, and temperature at several standard levels are available from the ALADIN reanalysis outputs, from which wind shear and vertical temperature gradient can be calculated. Verification allows for point comparison with data from sounding measurements, for example, from Prague, Libuš.
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Validation of Measurement Wind Assistance in the 100 Metre Sprint
Vokoun, Martin ; Kaplan, Aleš (advisor) ; Sýkora, Miloslav (referee)
Tittle (Thema works): Validation of Measurement Wind Assistance in the 100 Metre Sprint Student: Bc. Martin Vokoun Supervisor: PhDr. Aleš Kaplan, Ph.D. Aims: To practically verify the relevance measurement by the wind - gauge in the 100 metre sprint according to the current rules of athletics and compare them with our experimental measurement. Methods: We used an experimental measurement and methodological study for this diploma thesis. The essence of this work was measurement by five other wind - gauges bordering the 1OOmetres track, whereas one of them was placed on the opposite side than the official one and the other ones. The essence of this methodological study was a confrontation of advantages and disadvantages of current measurement by one wind - gauge and our experimental one. Results: Thanks to our experimental measurement and following methodological study we reached the result that to provide higher objectivity of measurement the wind assistance we need two wind - gauges standing against each other (at the inner and the outer border of the track). Further we made sure that measurement by larger number of wind - gauges is more objective than measurement with one wind - gauge. But in the most of cases the dates of the official wind - gauge are approximately the same as the average dates...
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Climate operation at the turn of the 18th and 19th century in memories of F.J. Vavák
Málková, Štěpánka ; Soukupová, Jana (advisor) ; Vokoun, Martin (referee)
This thesis focuses on documentary sources, mainly chronicles and memoirs of historical and contemporary terms and their use for meteorological purposes. The climate in the end 18th and the beginning 19th centuries, influenced mainly conclude the Little Ice Age, which was characterized by a strong cooling and temperature fluctuations. Memories of F. J. Vavák, neighbour and mayor of Milčice were investigated from the years 1770 to 1816 and evaluated records on weather and other factors affecting the climate and the evolution of agricultural crops between the years 1770-1816. This work also describes the historical context and inclusion in the context of historical and climatological during arising from the memories of František J. Vavák and impact on the life of the time population.
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Climate change caused by volcanic eruptions
Kolářová, Iveta ; Vokoun, Martin (advisor) ; Soukupová, Jana (referee)
This Bachelor thesis is engaged in climate changes caused by volcanic eruptions and explains, why after major volcanic eruptions follow volcanic winters. The first chapter shows the formation of volcanic activity and relations to climate changes. In three parts of the second chapter are described sectional factors (solar activity, problems of ocean currents and at-mospheric flow) to climate changes. In the third chapter are mentioned issues of science discipline of paleoclimatology and historical climatology, which combines a lot of disciplines as a geology, botany, zoology and more. The fourth chapter presents the main part of the work, because in this part is a description of the selected major volcanic eruptions of the last millennium and their consequences in the period after an explosion from the viewpoint of abnormalities in the weather. In conclusion of the Bachelor thesis is a search for an answers to question: Risks of powerful eruptions in the future and their impact on the human population.
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Analysis of flood protection measure on Cehnický potok – dry polder
Předota, Michal ; Bašta, Petr (advisor) ; Vokoun, Martin (referee)
This bachelor thesis aims on flood troubleshooting and on the flood protection Czech Republic uses. The theoretical part sums up the flood proces - its origin, process and types of flood. It describes the management of flood protection system and all means of flood protection. It contains a detailed description of dry polders, which represent a protective and retention function in the countryside. Further on it defines the concept of river flow, flood wave, active flood zone, degree of flood activity and small water reservoir. The practical part contains a characteristic of the area of interest of flow polder of the Cehnice village, through which flows the Cehnice stream. The efficiency and functionality of this polder has not been sufficiently verified yet and so the main benefit of this thesis is the calculation of transformation of the flood wave by the dry polder of Cehnice with the period of repeatability Q100, Q50 and Q20 using "numerical method for dry reservoir assessment", evaluation of the results and an analysis of the current flood situation in the area of Cehnice village.
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The climate in Ždár Peaks as described in documentary sources
Sobotková, Nicol ; Soukupová, Jana (advisor) ; Vokoun, Martin (referee)
The Protected Landscape Area Žďárské vrchy is in this bacherol´s work "The climate in Žďár Peaks as described in documentary sources" put into climate-historic context, particularly with regard to frequency of meteorological extremes and their impact on society. The importance is enhanced by the mere fact, that for the inhabitants of the Bohemian-Moravian Highlands, the knowledge of the then climate was a key for success-not only in economic development, but mainly in personal life, where this knowledge played a crucial role for their survival.
The starting point of this thesis is the definition of the discussed area, the definition of documentary sources from the perspective of climate and the characteristics of weather extremes. Historical data were taken from archives, mainly from nearby archives and from chronicles from the region of Žďárské vrchy and surrounding areas. The core for this thesis is the period before 1900, when scientific measurements were not used. Valuable reports are then the records of weather, climate conditions, catastrophes, but also about the deaths of bell-ringers. The information about grain fertility, crops or harvests are important, as well. According to character of the weather in the chosen area, the records are divided into author´s own seven-stage scale of extreme phenomena and they are put into local and regional context. The assessment is carried out by using tables, in which years are characterised according to genuine climatic conditions. Despite deviations caused by insufficient amount of data and inaccurate measurement, the data in question are similar to other observed proxy data. The study of climate in the Protected Landscape Area Žďárské vrchy in historical context can supplement climate-historical database and other research.
Climate of the past centuries in the region Žďárské vrchy shows that extreme events were common in there. Every year, people had to cope with harsh weather conditions. Why is then the question of weather extremes still open? The future threatens with global climate changes. If people do not stop governing the nature, the natural climate cycle will disrupt anthropogenic evolution.
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Conditions for tornadoes forming over the Czech Republic
Seidlová, Jana ; Vokoun, Martin (advisor) ; Soukupová, Jana (referee)
The goal of this bachelor's thesis is to review a situation of tornadoes, occurrences of tornadoes and also results of violent winds which accompany thunderstorms above Czech Republic region.
The first part looks at conditions required for the formations of tornadoes starting from a clear sky up to thunderstorm cloud. Then it describes development from a thunderstorm and associated hazards up to a tornado. Between main conditions belongs an unstable air mass which reaches high altitudes, high relative humidity, wind shear and vorticity. It also describes real occurrences of stronger tornadoes at Czech Republic.
In following part there are processed results including comments with graphical outputs from individual data gathered from particular occurrences. The time span of this thesis is limited by availability of historical data (chronicles, etc.) and they are processed from year 1500 up to year 2015. Results of analysis include remarks and they are refined
in discussion. For further and more complex overview about tornado occurrences at our country is necessary to have larger quantity of more precise data.
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Floods in history of Starý Plzenec
Šalomounová, Simona ; Vokoun, Martin (advisor) ; Bašta, Petr (referee)
This work focuses on the occurrence of historical flood situations on the Vltava, Berounka and Úslava rivers. In case of the Úslava river, the specific hydrometric profile is Pilsen Koterov. The aim is to summarize these flood events, to trace them back in town chronicles and to process data from the Czech Hydrometeorological Institute. The completed processing of data from the Czech Hydrometeorological Institute has revealed the occurrence of flood situations in this area in particular months and seasons.
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Aurora borealis - the causes, the historical cases, context.
Richterová, Jaroslava ; Soukupová, Jana (advisor) ; Vokoun, Martin (referee)
The subject of this thesis is to assess whether the people in the past were aware of the aurora borealis and how they perceived it. Then to present examples of this observation from the rare documentary sources. The first part of this thesis is aimed to introduce the solar activity, solar cycle and the whole formation of the aurora borealis.
The second part deals with the inclusion of a description of the auroras, which were found in the chronicles, into clear groups. There are presented graphs of the auroras occurencesin the last section. This appearance is finally compared with the frequency of the sun spots.
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