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Size segregated aerosol within atmospheric boundary layer
Traxmandlová, Nikola ; Hovorka, Jan (advisor) ; Jančík, Petr (referee)
Phenomenon of industrial grounds placed near residential areas can be frequently detected in European cities, which may cause decrease of air quality in these areas. The aim of this diploma thesis is to determine level of concentration and size distribution of aerosol in the planetary boundary layer above the residential area and industrial complex of Škoda auto a.s. in Mladá Boleslav city by using remotely controlled airship. Thereby, the thesis extends terrestrial experiment realized in February and March 2013 which revealed no significant impact of industry and traffic on air quality. Size distribution and concentration of aerosol particles in range from 11.5nm to 10µm with integration time one second or one minute (depending on measure mode - SINGLE or SCAN) was measured by two aerosol spectrometers placed in dirigible gondola during 13 flights on February 11, 2015. SINGLE mode lead the airship in one stable flight level during one flight above residential area and industrial complex of Škoda auto a.s. Whereas SCAN mode changed flight level every two minutes during the flight of airship above sports fields in residential zone only. Exhausts of car painting halls and place of automobile loading were identified as the sources of nanoparticles, PM1 a PM2.5 and coarse aerosol in the industrial area...
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Mathematical modelling of air-flow in geometrically complicated areas
Fuka, Vladimír ; Brechler, Josef (advisor) ; Fürst, Jiří (referee) ; Jaňour, Zbyněk (referee)
The Charles University Large-eddy Microscale Model (CLMM) and its application are presented. It is a numerical model for simulation of turbulent flow and dispersion in the planetary boundary layer. CLMM solves the incompressible Navier-Stokes equations in the Boussinesq approximation and describes turbulence using the large eddy simulation. Three applications of the model are presented. In the first case, the model is applied to the stable boundary layer over a flat terrain. The second case presents the simulations of stably stratified flows over obstacles. The last case deals with the dispersion of a hazardous material within an urban canopy. It was performed in the frame of the COST Action ES1006 and uses the Michelstadt flow and dispersion dataset for model validation.
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Vertical temperature profile in atmospheric boundary layer
Gvoždíková, Blanka ; Pešice, Petr (advisor) ; Sedlák, Pavel (referee)
Submitted bachelor thesis discusses the issue of the atmospheric boundary layer. First of all, it addresses the boundary layer's thermal characteristics which are very variable near the Earth's surface. For this purpose we have chosen the observatory in Kopisty near Most where a tower meteorological measurement is performed. In addition the air temperature measurements from Milešovka observatory were included to a dataset, too. It is assumed that this mountain weather station due to its position can represent conditions of the free atmosphere. But if we compare some thermal characteristics of the air at different height levels, we'll figure out that the air temperature measurements at Milešovka are highly influenced by radiation balance of the Earth's surface. Despite this fact, the analysis of air layer between Kopisty and Milešovka gives an idea of a continuous-time behavior of air temperature characteristics. This bachelor thesis describes in detail the air temperature variations and the temperature lapse rate variations in several height levels, the variability of thermal stratification or the incidence and extent of air temperature inversions.
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Flow and diffusion characteristics inside the urban area
Chaloupecká, Hana ; Jaňour, Zbyněk (advisor) ; Brechler, Josef (referee)
Title: Flow and diffusion characteristics inside the urban area Author: Hana Chaloupecká Department: Department of meteorology and enviroment protection Supervisor: prof. RNDr. Zbyněk Jaňour, DrSc., IT AS CR, v. v. i. Supervisor's e - mail: janour@it.cas.cz Abstract: Uniqueness of different towns, consists of various shapes of buildings. The main topic of this work is to compare concentration diffusion within groups of buildings of various types. We pursued houses made of single blocks of two different lengths - they were placed parallel or in courtyards. For research of pollution diffusion within the housing estates a method of physical modelling has been used. For this purpose we summarized a theory of atmospheric boundary layer and physical modelling at first. Then we pursued experiments. Measuring took place in a model in scale 1 : 300 inside an aerodynamic wind tunnel of the Institute of Thermomechanics AS in Nový Knín. We checked out the requirements placed on similarity of the real boundary layer and boundary layer modelled in the tunnel. By the measuring of concentration in urban areas we weren't watching a plume from the pollution source but we were studying an inversion task. We measured concentrations in two fixed points from different point sources inside the defined areas. A sensitivity of...
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Atmospheric greenhouse gases - new type of measurements in the Czech Republic
Čermáková, Lenka ; Sedlák, Pavel (advisor) ; Zíková, Naděžda (referee)
The current condition, development and functioning of ecosystems is greatly influenced by the ongoing global change, which is probably caused by the increased concentrations of greenhouse gases in the atmosphere originating from human activity. Ecosystems are able to some extent cope with the consequences of global change on their own, and therefore ensure their future preservation. To understand the forces driving global change, we need detailed quality data from long-term observation. Quantification of substance and energy flows in different ecosystems and ecosystem valuation ability to bind air carbon allows us to model their development, both in current conditions and under conditions of global change. This thesis presents the current research methods of atmospheric boundary layer flows, while highlighting their advantages and pointing out their drawbacks. It also enables a better understanding of new methods of observation through the tall towers. The thesis presents some of the existing tall towers and describes their ways and methods of measurement. A part of the thesis is devoted to a tall tower which is planned to be built in the Czech Republic between municipalities Košetice and Křešín u Pacova. It provides an overview of methods, instrumental and technical equipment and facilities of the new tall...
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Microscale flow and diffusion characteristics inside the urban area
Kukačka, Libor
Title: Microscale flow and diffusion characteristics inside the urban area Author: Libor Kukačka Department: Department of meteorology and enviroment protection Supervisor: prof. RNDr. Zbyněk Jaňour, DrSc., IT AS CR, v.v.i. Supervisor's e-mail address: janour@it.cas.cz Abstract: Dispersion of pollutants in the atmosphere of urban areas is the important task in environmental sciences. The main goal was the quantitative studying of a flow in a symmetrical urban built-up area depending on a running on flow direction. There was given a theoretical base of the physical modelling of the atmospheric boundary layer in this work. The measurement was done with a model of the urban build-up area at a scale of 1:200 in the aerodynamic wind tunnel of the IT AS CR, v.v.i. in Nový Knín. The requirements to the similarity to a real atmospheric boundary layer and a model boundary layer in the wind tunnel were accomplished. Velocity fields, concentration fields and fields of scalar fluxes were measured in the area of a rectangular intersection. Results of the experiment showed significant sensitivity of the velocity field about the running on flow direction that extensively influenced ventilation of street canyons. Keywords: air pollution, atmospheric boundary layer, physical modelling, dispersion of passive contaminant,...
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The Physical Modelling of the Flow above the Complex Terrain
Houbová, Eva
Článek popisuje řešení jednoho případu znečišťování ovzduší-v oblasti s komplikovaným terénem Jablonného nad Orlicí.Problém byl modelován fyzikálně.Po stručné zmínce o řešení pomocí matematického modelování následuje podrobnější popis modelování fyzikálního, v aerodynamickém tunelu.Je uveden přehled základních rovnic pro proudění tekutiny a podmínek podobnosti.Při fyzikální simulaci (1:1000) byl vyšetřován vliv dvou bodových zdrojů SO2.Byla použita Townsendova hypotéza o nezávislosti na Reynoldsově čísle. Šíření emisí se zkoumalo v aerodynamickém tunelu (při ÚT AV ČR): kvalitativně laserovým nožem a kvantitativně za použití analyzátoru IREX (ve spolupráci s Ústavem pro hydrodynamiku).Modelovaná atmosféra měla neutrální teplotní zvrstvení.Z hodnot přízemních koncentrací naměřených na modelu byly určeny přízemní koncentrace reálné. Nejvyšší míra znečištění byla prokázána na sídlišti.Lze předpokládat, že se emisní situace v Jablonném nad Orlicí zlepší,jestliže se podaří ve větším rozsahu rozšiřovat vytápění města plynem.
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