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Analysis of wind gusts over the area of the Czech Republic
Pop, Lukáš ; Sokol, Zbyněk (advisor) ; Picek, Jan (referee) ; Pelikán, Emil (referee)
The Ph.D. thesis deals with extreme wind gust analysis over the area of the Czech Republic. The first part of the thesis deals with processing of wind measurements, in particular maximum wind gusts measurements. Analysis of high-frequency wind measurement using 3-D sonic anemometer on the Kopisty station is included. Homogenization of the highest daily wind gusts was performed. Descriptive statistical analysis of measured wind gust values was performed. The following part of the thesis describes statistical theory of extreme values and discusses its applicability to wind gust data. Some theoretical findings were obtained. Numerous numerical experiments were performed focused on evaluation of proposed method. In the last part of the thesis station measurements were processed using the proposed methods and a model of dependence between extreme and mean wind climate was derived. The model was applied to the map of mean wind climate calculated earlier on the Institute of Atmospheric Physics and thus a map of extreme wind climate was obtained. The accuracy of this map was estimated. The map was compared with other maps of extreme wind calculated by other authors earlier.
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Utilization of analysis of the spatial relationships between meteorological variables in data assimilation into a numerical weather prediction model
Sedláková, Klára ; Sokol, Zbyněk (advisor) ; Řezáčová, Daniela (referee)
UTILIZATION OF ANALYSIS OF THE SPATIAL RELATIONSHIPS BETWEEN METEOROLO- GICAL VARIABLES IN DATA ASSIMILATION INTO A NUMERICAL WEATHER PREDICTION MODEL Quality of initial conditions has a big impact on the accuracy of numerical forecast. The aim of the preparation of the initial conditions is to modify the first guess of the atmospheric state based on the observed data of the meteorological variables so it fit the actual atmospheric state. At present these conditions are usually prepared by objective analysis or by assimilating measured data into model fields. One of the method of the data assimilation is a 3D variational method (3D VAR). It prepares the initial model conditions so that the model fields correspond to actual measured values, while maintaining the spatial relationships between the values of model variables. By utulising the spatial relationships we can improve the initial conditions and so the forecast. In this work we concentrate on study of the spatial relationship in the convective storms based on correlation analysis of the model variables. We used the model data from COSMO model with horizontal resolution 2.8 km, which were describing 152 convective storms in all the vertical levels. The analysis proved storng relationship between vertical speed, vertical speed and air...
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The exploitation of remote sensing for the analysis and progress of rainfalls
Bližňák, Vojtěch ; Sokol, Zbyněk (advisor) ; Setvák, Martin (referee) ; Pešice, Petr (referee)
The thesis is divided in two parts. The first part deals with the areal distribution of short-term convective rainfalls with regard to the influence of altitude. Precipitation estimates based on combination of rain gauge and radar data are used for this purpose. Statistical tests proved that the areal distribution of hourly convective rainfalls does not depend on altitude. Besides data containing precipitation events only, all measured data were statistically analysed regardless of the fact whether precipitation occurred or not. In this case it was found out that the relationship between hourly rainfall totals and altitude depends on the considered threshold of rainfall totals. When all data were considered, i.e. a threshold value was set to zero, an increase of rainfall totals well correlated with altitude. The dependence slowly disappeared with an increasing threshold. The areal distribution of 6 hour rainfall totals proved higher values in the area of south Bohemia. The most frequent synoptic patterns were northwest cyclonic situations (NWC) and cyclone over the Central Europe (C). The second part of the thesis is focused on satellite data exploitation, as measured by meteorological satellite Meteosat Second Generation, for convective precipitation estimates. The Convective Rainfall Rate (CRR) algorithm,...
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Study of bias correction for data assimilation in NWP model ALADIN
Benáček, Patrik ; Brožková, Radmila (advisor) ; Sokol, Zbyněk (referee)
Satellite sensor AMSU-A provides passive measurements of the radiation emitted from the earth's surface and the atmosphere. The radiances contain temperature and humidity information, but in order for this information to be directly assimilated in a numerical weather prediction (NWP) system, biases between the observed radiances and those simulated from the model first guess must be corrected. After the introduction we recall a notion of analysis, data assimilation and implementation in numerical model ALADIN, which is used by the Czech Hydrometeorological Institute. Then we introduce two radiance-bias correction schemes so-called Harris and Kelly method and variational correction method VarBC. In the last part of my thesis are presented the results of both correction methods for satellite measurements, available in one month periods, and effect of correction demonstrated on the figures.
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The spread of moisture from sources of Mondi SCP and their impact on the microclimate after the project ECO PLUS - Installation of a new paper machine PM19
Sokol, Zbyněk ; Řezáčová, Daniela
The report summarizes the results of the assessment of the impact of changes in humidity and heat emissions from sources of Mondi SCP for selected climatic characteristics associated with the expansion of production at the new paper machine PS19A. The assessment is based on a comparison of impacts to the existing system resources, including an increase in pulp production (Project 2000), and extended system of resources associated with the operation of PS19A. The results were obtained by applying a mathematical model CT-PLUME/MONDI_R. The calculations were performed for the winter part of the years 2011 to 2014 and included an assessment of the impact of point and diffuse sources on the climatic characteristics of the model area.
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Study of the impact of the new energy block Domoradice on local climate II
Sokol, Zbyněk ; Řezáčová, Daniela
The study stems from a previous work, where we used a mathematical model CT-PLUME / DOM. It is a basic model CT-PLUME adapted to assess the effect of mechanical cooling towers located in Domoradice on the model area. This study differs from the previous one in two respects: it processes 3-year period (2013, 2014 and 2015) and in addition to the basic climatic characteristics pays attention to icing. For this study, the basic module used before should be extended to model the conditions for the formation of ice in the vicinity. The final version of the model used in this study is referred to as CT-PLUME / DOM-2.
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A study on the influence of Dukovany power station on microclimate for the EIA documentation
Sokol, Zbyněk ; Řezáčová, Daniela
The study stems from the previous studies. We adapted the basic mathematical model CT-PLUME to assess the impact of cooling towers with natural draft, stationed in Dukovany site, on the given model area of 60 km x 60 km. The evaluation used meteorological data from 2010-2015 and compared the effect of the current towers with the new system EDU1-4 specified by the customer. This study differs significantly from the previous works in two aspects. It uses 6-year period (years 2010-2015) of data and analyzes the impact of 8 configurations with natural draft cooling towers contemplated in connection with the expansion of the Dukovany power station. The mathematical model CT-PLUME was adapted to the conditions of a specific task and is referred to as CT-PLUME / EDU_3.
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