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Experimental measurements at the meteorological observatory Milešovka
Pešice, Petr
The Milešovka Observatory was established in 1905 and has since been continuously performing standard meteorological and climatological\nobservations and measurements that are the primary mission of the station.\nMilešovka but like Lysá hora or other mountain observatory attracts experimentalists whether thanks to their exposed\nlocation and harsh weather conditions, frequent occurrence of strong winds, low cloud cover,\nor the abundant occurrence of storms and atmospheric discharges. The Milešov Measure Report summarizes current and planned experiments conducted at the Observatory.
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Effects of orography on spatial distribution of convective precipitation in Banská Bystrica district (Slovakia)
Kvak, Róbert ; Müller, Miloslav (advisor) ; Pešice, Petr (referee)
Effects of orography on spatial distribution of convective precipitation in Banská Bystrica district (Slovakia) Abstract The presented diploma thesis deals with the issue of spatial distribution of convective precipitation over complex terrain in Banská Bystrica district in the middle part of the Slovak Republic. The primary aim of this thesis is to verify the relation between areal precipitation characteristics caused by deep convection, and morphometric terrain parameters in the study area. The next goal is to identify how the existence of terrain influences the precipitation mechanisms. Eight precipitation events with maximum areal daily totals in the warm part of years between 2005 and 2015 are studied in this thesis. The events are split into the four groups (S, W, E, N) with respect to prevailing direction of storm motion during respective days. The precipitation rating is based on rain gauge measurements and adjusted radar precipitation estimates produced in the INCA model. The spatial relation between convective precipitation and topography is quantified in radar pixels' network 1 x 1 km and in the closest surroundings (20 x 20 km squares) of the rain gauge stations. The products are using DEM with the 50 m, 1 km and 2 km spatial resolution. The strongest correlation is proved in the relation with...
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Cloud-top morphology of convective storms as observed by meteorological satellites
Radová, Michaela ; Setvák, Martin (advisor) ; Pešice, Petr (referee) ; Sokol, Alois (referee)
Title: Cloud-top morphology of convective storms as observed by meteorological satellites Author: Michaela Radová Department: Department of Atmospheric Physics Supervisor: RNDr. Martin Setvák, CSc., Czech Hydrometeorological Institute Abstract: This work focuses on study of features occurring at tops of convective storms, namely embedded warm areas, cold rings, cold-U/Vs and overshooting tops (OTs), mainly from the perspective of satellite observations. We have assembled a database of 104 subjectively detected cold rings and cold-U/Vs from the area of Europe. We discuss relationship between satellite- observed brightness temperature and cloud top height determined from radar measurements for storms with distinct cold-rings. Our results support the hypothesis that the warm area is a consequence of presence of central elevated dome reaching warmer lower stratosphere. Moreover, a storm with transformation of cold ring into cold-U is studied and an elevated plume above storm anvil in the warmer lower stratosphere is found to be a likely explanation of the warm area inside the cold-U. Both analyses confirm that thermal inversion above the tropopause is a necessary prerequisite for occurrence of cold rings and cold-U/Vs. We also propose a method for automated objective determination of spatial characteristics of...
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Factors determining bad thermal conditions in the Czech Republic
Venclová, Markéta ; Chládová, Zuzana (advisor) ; Pešice, Petr (referee)
This presented work deals with a weak thermal convection over the Czech Republic. The main objective is to identify areas and meteorological conditions which determined weak thermal convection in the atmosphere. Another objective is to describe surfaces and situations that are characterized with occurrence of decreasing air currents. This work may be useful for non-motorized aircraft pilots for which the occurrence of weak thermal convection and decreasing air currents will be very dangerous during the flight. In the first part there are described different ways of spreading heat through the atmosphere, this is followed by a general description of thermal convection, its distribution, origin and course. The second part deals with weak thermal convection, describes the decreasing thermal current, meteorological conditions and factors causing weak thermal convection. The third part contains the results of a questionnaire, which was sent among aeroclubs in the Czech Republic. The results of the questionnaire were compared with the information reported in the literature and in most cases they coincide. The cases which differed from the literature are more detailed in the discussion.
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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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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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Evalution of information from Meteosat 8 and the CZRAD network of meteorological radars in selected significant convective situations
Hajáková, Jaroslava ; Kastner, Jiří (referee) ; Pešice, Petr (advisor)
KAPITOLA ABSTRACT Abstract Topic of Mc. S. Thesis: Evaluation of information from Meteosat 8 and the CZRAD network of meteorological radars in selected significant convective situations. Abstract: This paper focused on comparing the information from the satellite Meteosat 8 and the CZRAD network of meteorological radars in selected significant convective situations. The main goals of this study were to assess how satellite and radar data respond on development of convection and if the satellite data responds on intenzifying convection before the radar data. For this purpose, four significant convective situations and associated areas (72 x 72 km) were selected, and the satellite and radar data were preprocessed. Appropriate differences of spectral channels (i.e. satellite methods) and radar products were chosen. The preprocessing involved data synchronization in time and location. The parallax correction was used for satellite data. Seven satellite methods were used - spectral channel IR 10.8 (TIR10.8), difference of channels WV 0.6 and IR 10.8 (TWV6.2 - TIR10.8), IR 13.4 and IR10.8 (TIR13.4 - TIR10.8), IR 12.0 and IR 10.8 (TIR12.0 - TIR10.8), IR 8.7 and IR 10.8 (TIR8.7 - TIR10.8,), NIR 1.6 and VIS 0.6 (REFNIR1.6 - REFVIS0.6) and the trispectral method. The trispectral method resulted from measurements of...
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Influence of the satellite spatial resolution and scan time on convective storms'overshooting tops detection
Růžičková, Markéta ; Setvák, Martin (advisor) ; Pešice, Petr (referee)
This paper deals with the possibilities of convective storms' overshooting tops detection as seen from satellites. These tops are characterized by a rapid development, their size is only a few kilometres in diameter and they are connected with the presence of hazardous weather. They can be identified as small clusters of very low temperatures in satellite imagery, but this nature depends on the scan time and the scan frequency of the specific satellite and on the other features presence at tops of convective storm. The temporal variability of minimum IR brightness temperatures at the cloud tops of selected convective storms is studied in this paper, namely on the basis of the Meteosat Second Generation (MSG) satellite datasets. But the main emphasis of this work is to analyse the influence of the operative meteorological satellites' spatial resolution on the minimal IR brightness temperature, which is related to height of the cloud top. The datasets acquired by the sensors SEVIRI, AVHRR and MODIS have been chosen for these purposes. Mostly the convective storms that occurred over the Europe in the year 2008 have been diagnosed. The scan time difference must be taken into account when datasets from MSG and the other polar orbit satellites are compared and this difference should be minimal. The minimum IR...
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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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