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Study of links between biogenic VOC emissions and concentration of tropospheric ozone
Zemánková, Kateřina ; Brechler, Josef (advisor) ; Bednář, Jan (referee) ; Braniš, Martin (referee)
Title of dissertation: Study of links between biogenic VOC emissions and concentration of tropospheric ozone Kateřina Zemánková, 2010 Dissertation directed by: doc. RNDr. Josef Brechler, CSc. Dept. of Meteorology and Environment Protection, Faculty of Mathematics and Physics, Charles University in Prague Presented work focuses on influence of volatile organic compounds from biogenic sources on concentration of tropospheric ozone. Volatile organic compounds (VOC) play an important role in the tropospheric chemical system. Together with oxides of nitrogen they form two major components of reactions leading to low-level ozone formation. Volatile organic compounds are emitted into the atmosphere from an- thropogenic as well as from biogenic sources. In global, VOCs from natural sources are approximately ten times higher in magnitude than those of anthropogenic origin. Biogenic VOCs are emitted from various sources among which the forest ecosystems predominate. Group of VOCs of natural origin comprises wide range of chemical com- pounds. Those emitted in highest concentrations are isoprene and group of monoter- penes. Emissions of biogenic VOCs from the area of the Czech Republic have been es- timated based on the high resolution land cover data giving detailed information of sigle tree species...
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The Evaluation of the Heavy Convective Precipitation Forecast
Zacharov, Petr ; Řezáčová, Daniela (advisor) ; Brechler, Josef (referee) ; Pešice, Petr (referee)
The thesis deal with the evaluation of the quantitative convective precipitation forecast and its uncertainty. Five convective events that produced heavy local rainfall in the Czech Republic were studied. The nonhydrostatic local model LM COSMO was run with a horizontal resolution of 2.8 km and an ensemble of 13 forecasts was created by modifying the initial and boundary conditions. Forecasts were verified by gauge-adjusted radar-based rainfalls. Ensemble skill and ensemble spread were determined using the Fractions Skill Score (FSS). The spread represents the differences between the control forecast and the forecasts provided by each ensemble member, while the skill evaluates the difference between the precipitation forecast and radar-based rainfalls. The numerical experiments used the FSS-skill and spread values related to four events to estimate the skill-spread relationship. The relationship was applied to a fifth event to estimate the QPF ensemble skill given the ensemble FSS-spread. A couple of test of FSS computing were performed. The analysis of these events proved, that the application of the new fuzzy verification scores in high resolution QPF is highly advisable. The new scores are more suitable then the traditional verification scores based on the contingency table. In order to asses the...
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Study of AMDAR data in NWP model ALADIN
Bučánek, Antonín ; Brožková, Radmila (advisor) ; Brechler, Josef (referee)
The impact of assimilation (using 3D-Var method) of aircraft measurements on forecasts of the numerical model ALADIN is studied in the present work. Methods of measuring several meteorological parameters by aircrafts and their recording to AMDAR message are shown. So called BLUE equation for production of an analysis (the best assessment of the state of atmosphere represented by a numerical model) is deduced. The equivalence between the BLUE equation and a minimization of the quadratic functional used by 3D-Var is shown. Essentials steps of integrating meteorological measurements to assimilation procedure are outlined. The process of assimilation used in Czech Hydrometeorological Institute is shown and the results of aircraft measurements assimilation are presented.
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Microscale flow and diffusion characteristics inside the urban area
Kukačka, Libor ; Brechler, Josef (referee) ; Jaňour, Zbyněk (advisor)
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 modeling 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 uxes 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 inuenced ventilation of street canyons.
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Využití velikostní distribuce a elementárního složení městského aerosolu pro odhadu hlavních zdrojů/procesů podmikronových Pražských aerosolu pomocí receptorové modelování metody-Bilinear Positive Matrix Factorization
Thimmaiah, Devraj ; Hovorka, Jan (advisor) ; Havránek, Vladimír (referee) ; Brechler, Josef (referee)
Thesis Summary In this study' the sourcesofambient aerosolsin th€ uÍbanatmosphereofPrague, Czech Republic are apportionedusing bilinear Positive Matrix Faďorization (PMF2). Prior to this worl limited use of PMF techniquehas b€ťÍ' ryplied to Prague aerosols while elsewherearoundthe world, it has beenaaively usedby aerosol scientiststo reap thebenefitsince its fint inÚoduction in tbevea 1993. ln the currentstudy,the combinď pctrte nmber size disributions and readily available gaseous concentration .láa $tÍE 'E.d b ryortioning winter sub.micron particle sources in the urbm atmospbc of hgr. Tlle anbient Particle Number Concentations (PNC) wereotxainedsing r Scmng Mobility Particle Sizer (SMPS) in the size rangebetweeÍr14.ó md 73ó.5 m (Btd9od dianaers) along with the ambient gaseous concentrationsof CO, SQ. l,io, ()O * ]\iQL q, CH4, and Non Methane Hydrocarbons(NMHC) at the reccprr sit< e xllqriped rooftop sampling station(at height about 25m above street leall 25E AsL) be|onging to th€ Institute for Environmentalstuďes, Cbates tJnngsal 0aoe.5ď 4, |7.46"N; longifude-l4o25' 14.92 E). It is situared insi& lb. rDncn$! borni:al garden (area 0.035 km2).The receptoÍsite is shie|dedfrom diÍcctsouccs ofpo|hrin and thereaÍeno streetcanyon conditionsthatmigbt affea Úr sr@ry cmúm The meteorological d-Í. coocÍnmg umd...
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Zlepšení metod předpovědi termické konvekce pro účely letecké meteorologie
Dvořák, Petr ; Řezáčová, Daniela (advisor) ; Brechler, Josef (referee)
This rigorous thesis is engaging by some processes in boundary layer of the atmosphere, namely rise and running of thermals, focused on vertical motion and speeds of thermals, and on methods of their measurement and forecasting. It exploits data, measured by the GPS receivers and loggers aboard of gliders and paragliders during flying over Czech Republic, and data from aerological soundings, provided by Praha-Libus observatory. Measurement was in progress in so called cross-country flight season 2007 and 2008. The solution of this research is improvement of forecasting of vertical velocity of thermals and can be used in specialised forecasts for private and recreative flying and in forecasts of thermal turbulence.
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