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Quasi-biennial oscillation of zonal winds in the tropical stratosphere
Kupčihová, Zuzana ; Pišoft, Petr (advisor) ; Mikšovský, Jiří (referee)
This thesis is about phenomenon of the quasi-biennial oscillation-the alternation of westerly and easterly zonal wind in the equatorial stratosphere with a mean period of 28 months. The structure of the thesis is following. Firstly it describes the general division of the atmosphere with the emphasis on vertical division according to the temperature, which is the most common in meteorology. Furthermore it depicts conditions in the stratosphere; temperature and mean zonal wind flow at the 100 hPa, 10 hPa level and comparision for the summer and winter months. The work introduces important stratospheric phenomena such as polar vortex, sudden stratospheric warming, Brewer-Dobson circulation. The entire third chapter is devoted to the quasi-biennial oscillation. The basic characteristic, the theory of formation and different impacts on the tropical and extratropical region are described. The whole thesis is summerized in the epilogue.
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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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Visibility at the Praha Ruzyne airport
Kusáková, Kateřina ; Žák, Michal (advisor) ; Pišoft, Petr (referee)
The goal of this bachelor thesis is to show the importance of visibility in flight operations. There are settled minima of visibility for each process, which must be achieved. Visibility has its own daily range, which is closely connected with solar radiation. Its also connected with a vertical structure of atmosphere, direction and speed of wind and current weather conditions. Visibility achieves its lowest values during intensive precipitations and in a fog. Mainly because of an appearance and lasting of a fog, there are compilations at the airport and very often a special procedures must be taken for an organization of flight operations. An appearance and lasting of a fog has a big influence on flight operations and that is why I pay an attention to this in my work. I concentrated myself not only on the daily range of visibility and its dependency on the direction of a wind, but on conditions of appearance and ending the fog as well.
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Analysis of Climate Model Outputs
Chládová, Zuzana ; Raidl, Aleš (advisor) ; Pišoft, Petr (referee) ; Kliegrová, Stanislava (referee)
Title: Analysis of Climate Model Outputs Author: RNDr. Zuzana Chládová E-mail: zuzana.chladova@gmail.com Department: Department of Meteorology and Environment Protection, Faculty of Mathematics and Physics, Charles University in Prague Supervisor: RNDr. Aleš Raidl, Ph.D. Supervisor's e-mail address: ales.raidl@mff.cuni.cz Consultant: doc. RNDr. Jaroslava Kalvová, CSc. Regional climate models are currently the most important tools regularly used for downscaling outputs of global climate models. This analysis compares control and future runs of the global climate models HadCM3, ECHAM5/OPYC3 and ARPÉGE/OPA and the regional climate models RCAO, RCA3, HIRHAM4, HIRHAM5 and ALADIN- CLIMATE/CZ with observed data and CRU data for the Czech Republic. In the period 1961-1990, the global climate models underestimated the air temperature in comparison with corresponding virtual time series representing real data; mean annual courses and variance of the temperature, on the other hand, were simulated satisfactorily. The results of the regional climate models showed overestimation of the model temperature in winter season, while in other seasons the model temperatures corresponded better with real values and the results of simulation were generally more accurate in comparison with global climate models. Concerning...
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Usage possibilities of the cloud products of satellite datasets
Šácha, Petr ; Pišoft, Petr (advisor) ; Mikšovský, Jiří (referee)
Title Usage possibilities of the cloud products of satellite datasets Author: Bc. Petr Šácha Department: Department of Meteorology and Environment Protection Supervisor: RNDr. Petr Pišoft Ph.D. Supervisor's e-mail address: Petr.Pisoft@mff.cuni.cz Abstract: Cloudiness plays an important role in the global energy and water cycle. In particular, the presence of clouds dominates the planetary albedo and takes part in many climate feedback processes. In this thesis a short informational overview of remote sensing, a description of EUMETSAT, satellites, which it used, its part CM- SAF and a search retrieval of current research is given at first. Then the study is focused on the cloud satellite products, especially on CFC (cloud fractional cover) and CTY (cloud type) products. Data sets of daily averages of these products are compared with the daily averages created from the surface SYNOP observations of the total cloud cover and cloud type in the area of the Czech Republic. In the case of big variances between the two examined datasets of daily averaged cloud coverage, possible causes like the sampling error, dependence on season, localization of the station and the elevation and type of cloudiness, are searched. Several statistic analyses and validation scores are computed. Finally, possibilities of the examined...
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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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Contemporary possibilities of atmosphere lightning detection
Nettl, Tomáš ; Žák, Michal (advisor) ; Pišoft, Petr (referee)
The aim of this thesis is to make a survey about posibilities of detection atmosferic discharges, describe their principles and properties. The other aim of thesis is comparing the systems CELDN and LINET. These two systems cover the area of Czech Republic. The first part of this work concerns of basic characteristic of flashes and electric properties of the atmosphere. The basic model of air discharges distribution in a storm and an electric field around is mentioned. Then the thesis describes the basic flash detection systems and the methods of detection.The end of the work describes systems covering Czech Republic - CELDN and LINET. Also basic characteristics of these systems derived from real data are discussed.
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Tropical cyclones - what do we know about them and how can they be forecasted?
Rulfová, Zuzana ; Žák, Michal (advisor) ; Pišoft, Petr (referee)
Nazev prace: Tropicke cyklony - co o nich dnes vime a jak je unu'me pfedpovidat Autor: Zu/aua Rnlfova Katedra (ustav): Kaledva meteoiologie a oclnaiiy prostfedi Vedonci bakalafske pnice: Mgr. Michal Zak, Ph.D. e-mail vodonciho: Midial.Zak'J'Tnff.cimi.cz Abstrakt: Talc* prace shrnuje soueasne inforniaee o /ivuUiini cA'kln tropicke cyklouy a jejich ucincicli na mofi a pri dcjsazeni pcviiiny. Json x,d.e popsany iiejcastf\jsi oblasti vyskytu, iejicli poimciiiovaiii v jediiotlivych oblastech a. jejich klaaifikaco podlo in- ttnrxity. Dale u1)sahuic sledovaci a pfedpovedni inetody a jejich uspcsnost. Na konci pracc je uvcden prcliltxl vyzna.iunych iropickych cykloii. Klicova slova: tropicka cyklony, cyklogencze. puzorovam, pfedpovod' Title: Tropical (.cyclones - what, do \\v know about them and how can they be fore- casted? Author: Zuzana Rnlfovd Department: Tho Department of Meteorology and Environment. Protection Supervisor: Mgr. Alichnl Zak, Ph.D. Supervisor's e-mail address: Michal.Zak^mfi'.cnni.c/, Abstract: This thesis summarizes the recently information about life cycle oftropical cyclone and its effects out at sea. and before and after landfall. There are described the most common areas of occurrence ot tropical cyclones, their naming in these areas and their intensity classifications. Then this thesis...
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Uncertainty of regional climate models outputs
Kliková, Barbora ; Kalvová, Jaroslava (advisor) ; Pišoft, Petr (referee)
This thesis focuses on examination of the ability of regional climate models (RCMs) to simulate precipitation patterns in the Czech Republic and on evaluation of uncertainties due to different global climate models (GCMs) driving the same RCM and due to different RCMs driven by a single GCM. Model outputs of regional climate models RCAO and HIRHAM driven by global climate models HadAM3H and ECHAM for period 1961-1990 were analyzed. It was shown that spatial variability of mean annual precipitation totals is mainly influenced by RCM. The global driving model determines areal mean and minimum values of precipitation totals for the Czech Republic. Both regional models overestimate the mean annual precipitation totals over most of the area, more markedly with driving model ECHAM. After the analysis of the further precipitation characteristics in selected grid points, it was shown that models RCAO and HIRHAM simulate most of the characteristics differently. Most of the characteristics were not expressed well by the models; the results of the model RCAO were better. Further, the model results distinctively differ between chosen areas. This variability is more noticeable for HIRHAM.
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