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Influence of hazardous EM fields on large objects
Klučka, Jaroslav ; Kovács, Peter (referee) ; Řezníček, Zdeněk (advisor)
This bachelor thesis deals with simulation of influences of electromagnetic field on an aircraft via computer program PAM-CEM. The aim of the simulation is verification of conditions for placing equipment and cables in chosen places. There were chosen two outer interfering electromagnetic fields: High Intensity Radiated Fields HIRF and a lightning bolt. During the simulation of HIRF, the plane was radiated by outer electromagnetic field. The decomposition of inner electromagnetic field was monitored during the exposure. Then, the electrical intensity was measured in three places, where the location of susceptible electronical devices was predicted. During the simulation of lightning bolt only indirect effects were taken into consideration. Current impulse was implemented into the skin of the aircraft and the decomposition of surface current was monitored.
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Possibilities of Using of Remote Detection Data for Convective Storms Intensity Nowcasting
Valachová, Michaela ; Žák, Michal (advisor)
Title: Possibilities of Using of Remote Detection Data for Convective Storms Intensity Nowcasting Author: Michaela Valachová Department: Department of Atmospheric Physics Supervisor: Mgr. Michal Žák, Ph.D., Department of Atmospheric Physics Abstract: Evolution of 60 isolated convective storms from 2016 and 2017, which formed in the region of Central Europe, is studied by means of multi-sensor observations. According to the reports from the European Severe Weather Da- tabase, two categories of storms are classified: severe and non-severe. Based on radar, lightning and satellite measurements, trends of storm characteristics are analyzed to ascertain their typical behavior. Lightning stroke rates and their change could well warn about the ability of the storm to become severe, therefore a Lightning jump algorithm was proposed within this work. From individual case studies follows that methods of remote sensing offer comprehensive information about convective storm life-cycles. In order to objectively determine crucial variables for estimating the storm se- verity, logistic regression models and regularized regressions (elastic net) are employed. In total 53 variables from the first 30, 60 and 90 minutes of the moni- tored storm lifetime are used to show their predictive skill. Results of the models indicate...
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Possibilities of Using of Remote Detection Data for Convective Storms Intensity Nowcasting
Valachová, Michaela ; Žák, Michal (advisor)
Title: Possibilities of Using of Remote Detection Data for Convective Storms Intensity Nowcasting Author: Michaela Valachová Department: Department of Atmospheric Physics Supervisor: Mgr. Michal Žák, Ph.D., Department of Atmospheric Physics Abstract: Evolution of 60 isolated convective storms from 2016 and 2017, which formed in the region of Central Europe, is studied by means of multi-sensor observations. According to the reports from the European Severe Weather Da- tabase, two categories of storms are classified: severe and non-severe. Based on radar, lightning and satellite measurements, trends of storm characteristics are analyzed to ascertain their typical behavior. Lightning stroke rates and their change could well warn about the ability of the storm to become severe, therefore a Lightning jump algorithm was proposed within this work. From individual case studies follows that methods of remote sensing offer comprehensive information about convective storm life-cycles. In order to objectively determine crucial variables for estimating the storm se- verity, logistic regression models and regularized regressions (elastic net) are employed. In total 53 variables from the first 30, 60 and 90 minutes of the moni- tored storm lifetime are used to show their predictive skill. Results of the models indicate...
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Fast measurements of magnetic signals generated by natural lightning discharges
Kolínská, Andrea ; Santolík, Ondřej (advisor) ; Kašpar, Petr (referee)
The main focus of this thesis is, first of all, electromagnetic radiation generated by natural lightning discharges. More specifically, the thesis is oriented towards analysis of the return strokes and preliminary breakdown processes. This thesis also summmarizes our current knowledge of lightning discharges, aiming more in detail at results of previous work concerning return strokes and their initiation. The analysis of measurements of the SLAVIA sensors provided us with detailed information on the character of 92 return strokes and 40 preliminary breakdown pulses which were recorded between October 2013 and June 2014. In 63 % of lightning flashes the amplitude of the largest preliminary breakdown pulse was lower than the amplitude of the corresponding return stroke, although the ratio of these amplitudes was prone to seasonal changes. In summer the sensors detected a higher percentage of lightning flashes for which the amplitude of the largest preliminary breakdown pulse was higher than the amplitude of the return stroke. The average time interval between the largest preliminary breakdown pulse and the first return stroke was approximately 10 ms. This measurement was also prone to seasonal changes, with the average time interval raising in summer. Moreover, the return strokes varied as to the shape of the...
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Influence of hazardous EM fields on large objects
Klučka, Jaroslav ; Kovács, Peter (referee) ; Řezníček, Zdeněk (advisor)
This bachelor thesis deals with simulation of influences of electromagnetic field on an aircraft via computer program PAM-CEM. The aim of the simulation is verification of conditions for placing equipment and cables in chosen places. There were chosen two outer interfering electromagnetic fields: High Intensity Radiated Fields HIRF and a lightning bolt. During the simulation of HIRF, the plane was radiated by outer electromagnetic field. The decomposition of inner electromagnetic field was monitored during the exposure. Then, the electrical intensity was measured in three places, where the location of susceptible electronical devices was predicted. During the simulation of lightning bolt only indirect effects were taken into consideration. Current impulse was implemented into the skin of the aircraft and the decomposition of surface current was monitored.
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