The bahaviour of ionospheric drift during a superstorm in November 2004
Kouba, Daniel
2014 - Czech
This article presents results obtained by processing the measurement drift in the F layer of the ionosphere from the Pruhonice observatory.Diurnal and seasonal behaviour of the ionosphere is examined. The effect of strong geomagnetic storms on the ionosphere is presented. V tomto článku jsou prezentovány výsledky získané zpracováním driftových měření ve vrstvé F ionosféry ze stanice Průhonice. Tyto výsledky lze rozdělit do dvou částí - zkoumání pravidelného chování klidné ionosféry a demonstraci chování ionosféry během silné geomagnetické bouře. Za pravidelné chování lze považovat denní a sezónní variace i variace odpovídající slunečnímu cyklu. Chování ionosféry za klidných podmínek je důležité znát z důvodu studia vlivu vybraných událostí. Těmi mohou být geomagnetické bouře, zatmění Slunce, přechody výrazných meteorologických front apod. V článku jsou shrnuty některé výsledky popsané v disertační práci [Kouba, 2014]. Pokud bude známo chování driftů za klidných podmínek i během různých poruch ionosféry, bude v budoucnu možno realizovat i předpovědi dynamiky ionosférických vrstev.
Keywords:
ionospheric F-layer; geomagnetic storm; drift measurements
Available at various institutes of the ASCR
The bahaviour of ionospheric drift during a superstorm in November 2004
This article presents results obtained by processing the measurement drift in the F layer of the ionosphere from the Pruhonice observatory.Diurnal and seasonal behaviour of the ionosphere is examined. ...
Geomagnetická aktivita a její vliv na ionosféru
Mošna, Zbyšek; Koucká Knížová, Petra
2014 - Czech
Cl anek se zab yv a vazbou geomagnetick e aktivity na ionosf eru. Je pops an mechanismus pusoben poru sen eho meziplanetarního pole slune cn ho v etru na zemsk e magnetick e pole v r uzn ych oblastech (vysok e a n zk e s rky). V praktick e c asti jsou prezentov any v ysledky m e ren z vertik aln ho ionosf erick eho sondov an v obdob geomagneticky poru sen e situace z oblasti st redn ch s rek ze stanice Pr uhonice. Je uk az an pokles maxim aln elektronov e koncentrace a zm ena v y sek vrstvy F2.
Keywords:
ionosféra; geomagnetická aktivita
Available at various institutes of the ASCR
Geomagnetická aktivita a její vliv na ionosféru
Cl anek se zab yv a vazbou geomagnetick e aktivity na ionosf eru. Je pops an mechanismus pusoben poru sen eho meziplanetarního pole slune cn ho v etru na zemsk e magnetick e pole v r uzn ych ...
HF Doppler Radar Observations of Geomagnetic Pulsations
Fišer, Jiří; Chum, Jaroslav
2014 - English
Geomagnetic pulsations interact with the ionosphere, which influences the propagation properties of high frequency (HF) radio waves. In this work we present results of an experimental study focused on investigation of relations between the geomagnetic pulsations observed on the ground and the Doppler frequency shift oscillations observed remotely in the ionosphere by a Doppler sounding system in the Czech Republic. We study mainly the dependence of phase shift between them on various parameters.
Keywords:
Doppler sounding; ionosphere; geomagnetic pulsations
Available at various institutes of the ASCR
HF Doppler Radar Observations of Geomagnetic Pulsations
Geomagnetic pulsations interact with the ionosphere, which influences the propagation properties of high frequency (HF) radio waves. In this work we present results of an experimental study focused ...
Acoustic-gravity, tidal, and planetary waves in the ionosphere
Koucká Knížová, Petra; Mošna, Zbyšek; Potužníková, Kateřina
2014 - Czech
Neutral atmosphere affects strongly the ionosphere. We study influence of the neutral wave activity on the ionosphere in range of periods from minutes to days (acoustic waves to planetary waves). Neutrální atmosféra je důležitým faktorem ovlivňujícím stav ionosféry. Analyzujeme vliv vln v oblasti period minuty (akustické vlny) až dny (planetární vlny).
Keywords:
acoustic waves; gravity waves; vertical coupling
Available at various institutes of the ASCR
Acoustic-gravity, tidal, and planetary waves in the ionosphere
Neutral atmosphere affects strongly the ionosphere. We study influence of the neutral wave activity on the ionosphere in range of periods from minutes to days (acoustic waves to planetary waves).
Changes in the electron concentration profiles and TEC during high solar activity
Boška, Josef; Mošna, Zbyšek
2014 - Czech
Keywords:
geomagnetic storm; ionospheric storm; total electron content
Available at various institutes of the ASCR
Changes in the electron concentration profiles and TEC during high solar activity
Device for Measurement of Optical Visibility
Rejfek, L.; Brázda, V.; Fišer, Ondřej
2013 - English
This paper is about a proposed device for the optical visibility measurement. This device is usable for monitoring of the fog mightiness. The principle of device is based on comparison of attenuation on two optical links. The fog mightiness is determined by the using of the Beer-Lambert Law. The philosophy of electrical arrangement is also explained.
Keywords:
Beer-Lambert Law; Optical Links; Optical Visibility; Mightiness of the Fog; Absorbance; Transmittance
Available at various institutes of the ASCR
Device for Measurement of Optical Visibility
This paper is about a proposed device for the optical visibility measurement. This device is usable for monitoring of the fog mightiness. The principle of device is based on comparison of ...
Subseasonal temperature trends in Europe (1961-2000) and their links to atmospheric circulation
Cahynová, Monika; Pokorná, Lucie
2013 - English
We use daily maximum and minimum temperatures and the daily temperature range from 136 stations in Europe in the period 1961–2000 to precisely locate their seasonal and subseasonal trends within the year. Linear trends are calculated for moving “subseasons” of 10, 20, 30, 60, and 90 days, each shifted by one day. Over most of Europe, the observed warming is greatest in winter. In Iceland and the Mediterranean, a pronounced warming is only present in summer. Significant autumn cooling was found in Eastern and Southeastern Europe for both TX and TN. Other non-warming periods occur in Western and Central Europe in February, April, and late June. Trends of DTR are inconclusive. Changes in the frequency of atmospheric circulation types usually explain a substantial part of the observed climatic trends; however, the influence varies between regions, times of the year, subseason lengths, numbers of circulation types, and input variables for the classification of circulation types.
Keywords:
air temperature; daily temperature range; trend; atmospheric circulation; classification
Available at various institutes of the ASCR
Subseasonal temperature trends in Europe (1961-2000) and their links to atmospheric circulation
We use daily maximum and minimum temperatures and the daily temperature range from 136 stations in Europe in the period 1961–2000 to precisely locate their seasonal and subseasonal trends within the ...
The impact of new water area on microclimate
Bartůňková, Kristýna; Sokol, Zbyněk
2013 - Czech
In this contribution the impact of new water area on local climate is studied. The area of interest is newly originated lake Most in northern Bohemia. The impacts on microclimate that are evoked by physic-geographical changes in the area are studied by the help of the NWP model COSMO. The part of this model is Lake Model FLake. Input data are measured at the meteorological observatory Kopisty and at the lake station that measures also the water temperature in 16 vertical levels to the depth of 20 m. First results show significant influence of lake existence on air temperature, especially in summer months (June, July and August). The maximum influence is 1.2°C cooling in the surface level of the atmosphere. With the rising distance from the surface the impact on air temperature is decreasing. Příspěvek se zabývá vlivem nově vzniklé jezerní plochy na lokální klima. Je motivován napuštěním antropogenního jezera Most na místě bývalého lomu Ležáky v severních Čechách. Vlivy na mikroklima, způsobené změnami ve fyzicko-geografických charakteristikách lokality, jsou zkoumány pomocí idealizovaných výpočtů numerického modelu COSMO, jehož součástí je také model jezera FLake. Vstupní přízemní data jsou získána měřením na meteorologické observatoři Kopisty a na stanici na jezeře, která měří rovněž teplotu vody v 16 vertikálních profilech až do hloubky 20 m. Pro popis vertikálního profilu atmosféry jsou využity analýzy meteorologických polí z Evropského střediska pro střednědobou předpověď (ECMWF). Z prvních výsledků vyplývá, že velká jezera zřetelně ovlivňují přízemní teplotu vzduchu v zimních a především v letních měsících, kdy za určitých meteorologických situací způsobují ochlazení vzduchu při zemském povrchu o více než 2°C. Se zvyšující se vzdáleností od zemského povrchu pochopitelně vliv jezera klesá. V horizontální rovině je vliv na změnu teploty patrný do vzdálenosti cca 3 km.
Keywords:
lake; microclimate; numerical modeling; COSMO
Available at various institutes of the ASCR
The impact of new water area on microclimate
In this contribution the impact of new water area on local climate is studied. The area of interest is newly originated lake Most in northern Bohemia. The impacts on microclimate that are evoked by ...
Analysis of temporal variability and spatial characteristics of heat waves in central Europe using extremity index
Lhotka, Ondřej; Kyselý, Jan
2013 - English
Heat waves have severe consequences on natural environment and society. Th e majority of studies defined heat waves from station data only, so there is a need to examine these events not only from the aspect of point characteristics of air temperature and duration, but also from the view of their spatial extent. In this study, heat waves over Central Europe were analysed using the gridded E-OBS dataset. Th e extremity index of heat waves, which takes into account their spatial extent, duration, and peak temperature, was proposed and used to analyse variability of heat waves over Central Europe from 1950 to present. We delimited 220 hot days and 21 heat waves and computed the extremity index for each heat wave. Th e eight most signifi cant heat waves based on the extremity index were visualized. Temporal variability of hot days and heat waves was analysed and we demonstrate that the number of hot days and the severity of heat waves have been increasing.
Keywords:
heat waves; central Europe; extremity index
Available at various institutes of the ASCR
Analysis of temporal variability and spatial characteristics of heat waves in central Europe using extremity index
Heat waves have severe consequences on natural environment and society. Th e majority of studies defined heat waves from station data only, so there is a need to examine these events not only from the ...
On Forward and Backward Scattering from Fog and Rain Drops
Fišer, O.; Rejfek, Luboš; Brázda, Vladimír
2013 - English
This contribution deals with the backward and forward scattering on dielectrical spheres. The well-known Rayleigh, Mie and Optical regions are discussed for frequencies regions 0.05 to 70 GHz and for optical wavelength of 830 nm. Some of our results fit the published one, some of them are different and the explanation of possible reasons is added. Also the formulas necessary to compute the radar reflectivity or attenuation due to fog and rain are presented.
Keywords:
Forward scattering; backward scattering; efficiency factor; Rayleigh region; Mie region; Optical region; mlha; déšť
Available at various institutes of the ASCR
On Forward and Backward Scattering from Fog and Rain Drops
This contribution deals with the backward and forward scattering on dielectrical spheres. The well-known Rayleigh, Mie and Optical regions are discussed for frequencies regions 0.05 to 70 GHz and ...
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