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Effect of volcanic ash to Air Transport
Soukop, Robin ; Šplíchal, Miroslav (referee) ; Chlebek, Jiří (advisor)
This master's thesis deals with the issue of volcanic ash as a complex and its impact on aviation, including the volcanic activity itself (conditions for its existence, for existence of eruptions and their basic products). In addition, the thesis also deals with effect of volcanic ash on aircraft and airports, possibilities of its detection or monitoring as well as mechanism of its spreading in airspace. The emphasis is laid mainly on air incidents related to volcanic ash and on danger it poses to the airspace of the Czech Republic.
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New Perspective on the Role of Gravity Waves in the Stratospheric Dynamics and Variability
Šácha, Petr ; Pišoft, Petr (advisor) ; Dameris, Martin (referee) ; Rieder, Harald (referee)
This thesis is concerned with the role of internal gravity waves (IGWs) in the stratospheric dynamics and variability demonstrating the effect of spatiotemporal distribution of their activity on the stratospheric dynamics and transport. The first part introduces a theoretical overview of the most recent as well as classical approaches used for description of the wave-mean interaction in the middle atmosphere. Methodology for an IGW analysis from the GPS radio occultation density data is described in the next chapter and the advantages of utilization of density data are listed. The third chapter presents results describing the peculiar dynamics and anomalous IGW activity in the Eastern Asia/Northern Pacific region. An important part is dedicated to a discussion of accuracy limits and usability of different IGW activity proxies. The possible impact of the localized IGW activity is investigated using a mechanistic middle and upper atmosphere model in the last chapter. Sensitivity simulations are used to demonstrate an important role of the spatial distribution of IGW activity for a formation of planetary waves and for the longitudinal variability of the Brewer-Dobson circulation. Implications for the middle atmospheric and climate change research are discussed along with consequences for parameterizations of...
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Climate characteristics of higher atmospheric levels
Kuchař, Aleš ; Pišoft, Petr (advisor) ; Žák, Michal (referee)
This work investigates the climatic characteristics of the upper atmosphere. The characteristics that were analyzed include air temperature, speed and direction of the zonal wind, geopotential height and total column of ozone or its mixing ratio in the individual levels of pressure. Data from projects NCEP/NCAR and ERA-40 reanalysis were used for these purposes. The data are present in a graphic form, particularly in the average monthly maps during 1978−2007 for the first one and during 1978−2002 for the second one with azimuthal projection for each hemisphere for the levels of 300, 100, 10 and 30 hPa. The results obtained are described and interpreted by a research of available literature.
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Vertical variability of the 11 years solar cycle influence within the middle and higher atmosphere
Kuchař, Aleš ; Pišoft, Petr (advisor) ; Laštovička, Jan (referee)
This work investigates changes implied by variability of temperature, zonal wind and ozone mixing ratio during the eleven-year cycle in the stratosphere and lower mesosphere. The analysis is performed by using multiple linear regression of the MERRA reanalysis dataset for the period 1979-2012. Furthermore, we describe possibilities of available dataset, which can be also considered for the study of the upper atmosphere. Results of this study show a qualitative agreement with other related studies in the stratosphere, we find substantial differences especially in the ozone concentrations above the stratopause. It has been shown more intensive sudden stratospheric warming during solar maxima and the associated impact on the Brewer-Dobson circulation in all fields of meteorological variables.
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Vertical variability of the 11 years solar cycle influence within the middle and higher atmosphere
Kuchař, Aleš ; Pišoft, Petr (advisor) ; Laštovička, Jan (referee)
This work investigates changes implied by variability of temperature, zonal wind and ozone mixing ratio during the eleven-year cycle in the stratosphere and lower mesosphere. The analysis is performed by using multiple linear regression of the MERRA reanalysis dataset for the period 1979-2012. Furthermore, we describe possibilities of available dataset, which can be also considered for the study of the upper atmosphere. Results of this study show a qualitative agreement with other related studies in the stratosphere, we find substantial differences especially in the ozone concentrations above the stratopause. It has been shown more intensive sudden stratospheric warming during solar maxima and the associated impact on the Brewer-Dobson circulation in all fields of meteorological variables.
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Global changes in the midlatitude stratosphere
Kozubek, Michal ; Laštovička, Jan (advisor) ; Halenka, Tomáš (referee) ; Metelka, Ladislav (referee)
Several phenomena in the middle latitude stratosphere are studied in the thesis. The reanalyses are utilized as a source of data for our study. Different reanalyses are compared each other and with observations and problems of reanalyses are shown. We are interested in connection between ozone, dynamics and other phenomena (Sudden Stratospheric Warmings, solar cycle, NAO etc.) in the stratosphere, mainly from 1979 to present using ERA-Interim, NCEP/NCAR reanalyses or satellite observations. The linear connection between total ozone difference and 100 hPa eddy heat flux is found in winter middle latitudes. Ozone trends in Europe and China are analysed. The meridional and zonal wind is also studied using MERRA reanalysis and model output (CCM SOCOL v3.0). The comparison of geographical distribution of geopotential height and meridional wind is done. Differences between MERRA and CCM SOCOL v3.0 has been observed for geopotential hight and meridional wind for winter season.
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Climate characteristics of higher atmospheric levels
Kuchař, Aleš ; Pišoft, Petr (advisor) ; Žák, Michal (referee)
This work investigates the climatic characteristics of the upper atmosphere. The characteristics that were analyzed include air temperature, speed and direction of the zonal wind, geopotential height and total column of ozone or its mixing ratio in the individual levels of pressure. Data from projects NCEP/NCAR and ERA-40 reanalysis were used for these purposes. The data are present in a graphic form, particularly in the average monthly maps during 1978−2007 for the first one and during 1978−2002 for the second one with azimuthal projection for each hemisphere for the levels of 300, 100, 10 and 30 hPa. The results obtained are described and interpreted by a research of available literature.
|
|
|
New Perspective on the Role of Gravity Waves in the Stratospheric Dynamics and Variability
Šácha, Petr ; Pišoft, Petr (advisor) ; Dameris, Martin (referee) ; Rieder, Harald (referee)
This thesis is concerned with the role of internal gravity waves (IGWs) in the stratospheric dynamics and variability demonstrating the effect of spatiotemporal distribution of their activity on the stratospheric dynamics and transport. The first part introduces a theoretical overview of the most recent as well as classical approaches used for description of the wave-mean interaction in the middle atmosphere. Methodology for an IGW analysis from the GPS radio occultation density data is described in the next chapter and the advantages of utilization of density data are listed. The third chapter presents results describing the peculiar dynamics and anomalous IGW activity in the Eastern Asia/Northern Pacific region. An important part is dedicated to a discussion of accuracy limits and usability of different IGW activity proxies. The possible impact of the localized IGW activity is investigated using a mechanistic middle and upper atmosphere model in the last chapter. Sensitivity simulations are used to demonstrate an important role of the spatial distribution of IGW activity for a formation of planetary waves and for the longitudinal variability of the Brewer-Dobson circulation. Implications for the middle atmospheric and climate change research are discussed along with consequences for parameterizations of...
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|
|
Effect of volcanic ash to Air Transport
Soukop, Robin ; Šplíchal, Miroslav (referee) ; Chlebek, Jiří (advisor)
This master's thesis deals with the issue of volcanic ash as a complex and its impact on aviation, including the volcanic activity itself (conditions for its existence, for existence of eruptions and their basic products). In addition, the thesis also deals with effect of volcanic ash on aircraft and airports, possibilities of its detection or monitoring as well as mechanism of its spreading in airspace. The emphasis is laid mainly on air incidents related to volcanic ash and on danger it poses to the airspace of the Czech Republic.
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