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Total Electron Content Measurement Using Digisonde and GNSS
Kouba, Daniel; Šauli, Petra
2009 - English
The digital pulse ionospheric sounder (Digisonde) of the University of Massachusetts Lowell has been operated in Pruhonice (geographic coordinates 50.0N, 14.6E) since 2004 for ionospheric study. Earlier, KEL Aerospace and ISP-42 ionosondes had also been operated. Hence, there is a long archive of bottomside ionospheric records for a period of about sixty years. In 2009, Topcon NET-G3 triple frequency Global Navigation Satellite System receiver will also be installed at the station, collocated with the Digisonde. GNSS receivers are becoming recognized as another source for ionospheric information. This year, the upgrade of Digisonde DPS-4 to model DPS-4D also will be realized. This new type will provide a much wider usage and expands the possibilities of our research. The GNSS and Digisonde measurements jointly will bring new improvements to the models of electron density profiles.
Keywords:
ionosphere; ionogram; TEC mapping
Available at various institutes of the ASCR
Total Electron Content Measurement Using Digisonde and GNSS
The digital pulse ionospheric sounder (Digisonde) of the University of Massachusetts Lowell has been operated in Pruhonice (geographic coordinates 50.0N, 14.6E) since 2004 for ionospheric study. ...
Database of Whistler-mode Chorus in the Equatorial Plane
Macúšová, E.; Santolík, Ondřej
2009 - English
Chorus emission is one of the most intense electromagnetic waves. Its source region is localised close to the geomagnetic equatorial plane within a few degrees. We present a unique database of whistler-mode chorus/hiss events obtained from the complete data set of wave measurements provided by the STAFF/DWP wave instrument on board TC-1 spacecraft. The TC-1 is one of two Earth orbiting satellites from the Double Star mission and it orbits close to the equatorial plane. Some instruments onboard both spacecraft are identical to those currently flying on the four Cluster spacecraft. The data base covers the full operational period of the spacecraft, between January 2004 and October 2007. All the events have been visually selected from the onboard-analyzed time-frequency spectrograms of magnetic search-coil measurements below 4 kHz.
Keywords:
Database; Whistler-mode; Chorus; Equatorial; Plane
Available at various institutes of the ASCR
Database of Whistler-mode Chorus in the Equatorial Plane
Chorus emission is one of the most intense electromagnetic waves. Its source region is localised close to the geomagnetic equatorial plane within a few degrees. We present a unique database of ...
Ionospheric response to the particular solar event as seen in the ionospheric vertical sounding
Mošna, Zbyšek; Koucká Knížová, Petra; Georgieva, K.
2009 - English
Two types of solar events (Coronal Mass Ejections -CMEs and their subset with rotational magnetic field, Magnetic Clouds - MCs and High Speed Solar Stream –HSS) are mainly responsible for geomagnetic and ionospheric (geospheric) disturbances. Three solar events from year 2004 were chosen and ionospheric responses by means of foF2 and h'F2 were studied.
Keywords:
geoeffectivity; critical frequency foF2; virtual height h’F2; Magnetic Cloud; High Speed Solar Stream; digisonde
Available at various institutes of the ASCR
Ionospheric response to the particular solar event as seen in the ionospheric vertical sounding
Two types of solar events (Coronal Mass Ejections -CMEs and their subset with rotational magnetic field, Magnetic Clouds - MCs and High Speed Solar Stream –HSS) are mainly responsible for geomagnetic ...
Analysis of Climate Model Outputs Using Linear and Nonlinear Statistical Techniques
Chládová, Zuzana
2009 - English
Regional climate models (RCMs) are currently one of regularly applied tools for localization of global climate models (GCMs) outcomes. This study is focused on analyses of mean daily temperature and precipitation using linear and nonlinear statistical techniques. 48 grid points of the regional climate models HIRHAM and RCAO and 29 meteorological stations of the Czech Republic were compared in the period 1961-1990. Mean annual courses of mean daily temperature and precipitation in the period 2071-2100 were analyzed at selected HIRHAM and RCAO grid points for A2 and B2 emission scenarios [IPCC, 2007]. Furthermore, time-delayed average mutual information (AMI) and autocorrelation function were analyzed. AMI and autocorrelation function were calculated for one selected time series of each grid point of the Czech Republic and Europe with a time lag varying from 1 to 10 days. The values of average mutual information were compared with values of autocorrelation function. Globální a regionální klimatické modely jsou v současnosti nejdůležitějšími nástroji při vytváření projekcí budoucího klimatu. V rámci předkládané práce byla provedena analýza schopnosti klimatických modelů modelovat budoucí klima pomocí lineárních a nelineárních statistických technik. Konkrétně byly porovnávány zvolené referenční a budoucí běhy regionálních klimatických modelů RCAO a HIRHAM na území České republiky. Pro 48 uzlových bodů těchto regionálních klimatických modelů a 29 meteorologických stanic na území České republiky byly porovnávány roční chody průměrné denní teploty a srážek pro období 1961–1990. Pro uzlové body byly sledovány roční chody průměrné denní teploty a srážek podle scénářů A2 a B2 pro období 2071–2100. V další části práce byla provedena analýza pomocí časově zpožděné míry vzájemné informace (MVI) a autokorelační funkce s časovým posunem od jednoho do deseti dní. Prostorové rozložení MVI bylo vyhodnoceno pro evropský kontinent se zaměřením na území České republiky.
Keywords:
RCMs; GCMs; Czech Republic; mean daily temperature; precipitation
Available at various institutes of the ASCR
Analysis of Climate Model Outputs Using Linear and Nonlinear Statistical Techniques
Regional climate models (RCMs) are currently one of regularly applied tools for localization of global climate models (GCMs) outcomes. This study is focused on analyses of mean daily temperature and ...
Analysis of heavy elements in air, fog and rime from Milesovka and Kopisty
Stoyanova, V.; Petrova, P.; Fišák, Jaroslav; Daskalova, N.; Tsacheva, Ts.; Marinov, M.
2008 - English
Aim of this study is to estimate the presence of heavy metal particles filter-collected in the air, fog and rime water from the polluted area of North Bohemia, Czech Republic. The proposed comparison of the obtained preliminary results for air born particles enriched of heavy metals with those captured in the fog and rime, combined with a comparative analysis of water-soluble and insoluble particles from the same samples (Fišák et al. 2007, 2008), could provide a basis for the most appropriate way for future analyzing of many other samples in similar routine manner. Cílem této studie je zhodnotit výskyt částiček těžkých kovů ve vzorcích získaných filtrováním vzduchu, vody z mlh a námraz ze znečištěné oblasti Severních Čech. Uskutečněné porovnání představuje předběžné výsledky částic obsažených ve vzduchu obsahujících těžké kovy zachycených v mlze a námraze. Spolu se srovnávací analýzou ve vodě rozpustných a nerozpustných částic ve stejných vzorcích (Fišák et al. 2007, 2008), může posloužit jako vhodný způsob pro následující analýzy dalších podobných vzorků.
Keywords:
fog-water; rime-water; soluble and insoluble components; electron analysis
Available at various institutes of the ASCR
Analysis of heavy elements in air, fog and rime from Milesovka and Kopisty
Aim of this study is to estimate the presence of heavy metal particles filter-collected in the air, fog and rime water from the polluted area of North Bohemia, Czech Republic. The proposed comparison ...
2-year results of hydrometeor attenuation research at 93 GHz on an 850 m terrestrial path
Kvičera, V.; Grábner, M.; Fišer, Ondřej
2008 - English
The results of 2 years of experimental research of attenuation due to hydrometeors at 94 GHz with V polarization on an 850 m path are presented. Both the cumulative distributions of attenuation due to all the hydrometeors together and the cumulative distributions of attenuation due to the individual hydrometeors are given. The results are compared with the relevant ITU-R recommendations. Výsledky dvouletého výzkumu útlumu způsobeného hydrometeory na trase 93 GHz (V polarizace) a v optickém pásmu 850 nm jsou prezentovány ve formě distribučních křivek. Odpovídají buďto totálnímu útlumu nebo útlumu podle jednotlivých typů hydrometeorů. Výsledky jsou porovnány s doporučeními ITU-R.
Keywords:
electromagnetic wave propagation; attenuation; attenuation due to hydrometeors; hydrometeors; propagation characteristics
Available at various institutes of the ASCR
2-year results of hydrometeor attenuation research at 93 GHz on an 850 m terrestrial path
The results of 2 years of experimental research of attenuation due to hydrometeors at 94 GHz with V polarization on an 850 m path are presented. Both the cumulative distributions of attenuation due ...
Possible Seismic Influence on VLF Wave Intensity: Observations by a Low-Altitude Satellite
Němec, František; Santolík, Ondřej; Parrot, M.
2008 - English
We present results of a statistical study of VLF (up to 10 kHz) wave intensity measured by a low-altitude spacecraft in the vicinity of earthquakes. The data from the French DEMETER spacecraft (altitude about 700 km, nearly Sun-synchronous orbit) that was specially developed for such kind of studies are used. The recently developed two-step data processing method is briefly introduced and the main obtained results are reviewed. Finally, a simple independent test of the obtained results is done in order to give an additional evidence for the existence of possible seismic-related effect. Our results indicate that there is a decrease of power spectral density of electric field fluctuations shortly (0-4 hours) before the time of the main shock. This decrease was observed close to surface earthquakes (depth less than 40 km) with magnitude larger than or equal to 4.8 and only during the night. No similar effect was observed for deep earthquakes nor during the day. Výsledky statistické studie nízkofrekvenčních (f < 10 kHz) elektromagnetických vln pozorovaných na družici s nízkou orbitou v blízkosti zemětřesení. Naše výsledky indikují, že krátce (0-4 hodiny) před hlavním otřesem dochází k poklesu výkonové spektrální hustoty elektrických fluktuací. Tento efekt byl pozorován v blízkosti povrchových (hloubka menší než 40 km) zemětřesení s magnitudou větší nebo rovnou 4.8 během noci. Žádný podobný efekt nebyl pozorován během dne.
Keywords:
seismo-electromagnetic effects; VLF electromagnetic waves; DEMETER
Available at various institutes of the ASCR
Possible Seismic Influence on VLF Wave Intensity: Observations by a Low-Altitude Satellite
We present results of a statistical study of VLF (up to 10 kHz) wave intensity measured by a low-altitude spacecraft in the vicinity of earthquakes. The data from the French DEMETER spacecraft ...
Analysis of Critical Frequencies in the Ionosphere
Mošna, Zbyšek; Šauli, Petra; Santolík, Ondřej
2008 - English
Ionosphere is a highly variable system. The most used way how to describe the state of ionosphere is to deal with the critical frequencies which directly reflect the maximum electron concentration in an ionospheric layer. Ionosphere, like many natural systems, exhibits scaling properties. In this paper, we show results of the scaling analysis of ionospheric data from Pruhonice observatory, geomagnetic, and solar flux data from 1957-2005. Ionosféra je vysoce proměnlivý systém. Pro popis ionosféry se často používají kritické frekvence, které udávají maximální elektronovou koncentraci v dané ionosférické vrstvě. Ionosféra, podobně jako mnoho dalších přírodních systémů, vykazuje scaling vlastnosti. V tomto článku jsou uvedeny výsledky scaling analýzy z ionosférických dat ze stanice Průhonice, geomagnetických dat a dat sluneční aktivity z let 1957-2005.
Keywords:
ionosphere; critical frequencies; scaling; monofractal; multifractal; selfsimilarity
Available at various institutes of the ASCR
Analysis of Critical Frequencies in the Ionosphere
Ionosphere is a highly variable system. The most used way how to describe the state of ionosphere is to deal with the critical frequencies which directly reflect the maximum electron concentration in ...
Ionospheric F-region Drift Measurements in Observatory Průhonice, Seasonal Quiet Day Patterns
Kouba, Daniel; Šauli, Petra; Boška, Josef; Santolík, Ondřej
2007 - English
In the paper we concentrate on the F-region drift-data measured by the ionospheric station Pruhonice (50.0N, 14.6E). We demonstrate application of the skymap points selection method on the data set collected in 2006, during a period of low geomagnetic and solar activity. Using histograms of horizontal and vertical velocity components we found prevailing directions of plasma motion corresponding to specified ranges of velocities. Within the analyzed data we found significant decrease of the daily-maximal horizontal component from winter to summer 2006. Článek se zaměřuje na ionosférická driftová měření v F-vrstvě na stanici Průhonice. Demonstrujeme aplikaci metody výběru zdrojových bodů na datech pro rok 2006, tj. pro období nízké geomagnetické a sluneční aktivity. Na histogramech horizontální a vertikální složky rychlosti nacházíme převažující směr pohybu plazmatu pro různé úrovně rychlostí. V analyzovaných datech jsme pro období zima – léto nalezli výrazný pokles denního maxima horizontální složky.
Keywords:
ionospheric drift; Digisonde; F-region; skymap
Available at various institutes of the ASCR
Ionospheric F-region Drift Measurements in Observatory Průhonice, Seasonal Quiet Day Patterns
In the paper we concentrate on the F-region drift-data measured by the ionospheric station Pruhonice (50.0N, 14.6E). We demonstrate application of the skymap points selection method on the data set ...
Evaluation of uncertainty in the area related quantitative precipitation forecast of heavy convective precipitation
Zacharov, Petr, jr.; Řezáčová, Daniela
2007 - English
Extreme convective events have been studied with numerical weather prediction model LM COSMO (horizontal resolution of 2.8km) and radar data. An ensemble of 13 forecasts, which followed from modyfying initial fields, was created for two of analyzed events. Uncertainty in area-related quantitative precipitation forecast (QPF) was evaluated by fraction skill score (FSS) to quantify an ensemble spread and skill. The spread assesses a difference between a control forecast and ensemble member forecasts and the skill evaluates a difference between a precipitation forecast and radar derived precipitation. The uncertainty analysis shows an effect of forecast lead time and space scale as well as a sensitivity to the area structure of precipitation field. In this paper we summarize our first results dealing with the scale influence on the ensemble spread and skill. Pomocí numerického předpovědního modelu LM COSMO (horizontální rozlišení 2.8km) a radarových dat jsme studovali události s extrémními konvektivními srážkami. Pro dvě vybrané události byl vytvořen ensemble 13-ti předpovědí, ktarý vznikl díky modifikaci počátečních podmínek. Nejistota v plošné předpovědi srážek (QPF) byla vyhodnocena pomocí verifikační techniky FSS ("Fraction Skill Score"). Byl stanoven rozptyl ("spread") a kvalita ("skill") ensemble předpovědi. Rozptyl ("skill") stanovuje rozdíl mezi kontrolní předpovědí srážek (předpověď s nezměněnými poč. podmínkami) a předpovědí srážek jednotlivých členů ensemblu. Kvalita ("skill") stanovuje rozdíl mezi polem srážek získaným z radarových měření a členy enseblu. Analýza ukazuje vliv doby předpovědi, velikosti plochy a stuktury pole předpovědi srážek na kvalitu a rozptyl předpovědi. V této studii shrnujeme první výsledky vlivu velikosti plochy pro výpočet plošné srážky na kvalitu a rozptyl ensemble.
Keywords:
verification; quantitative precipitation forecast; forecast spread; forecast skill; ensemle forecast
Available at various institutes of the ASCR
Evaluation of uncertainty in the area related quantitative precipitation forecast of heavy convective precipitation
Extreme convective events have been studied with numerical weather prediction model LM COSMO (horizontal resolution of 2.8km) and radar data. An ensemble of 13 forecasts, which followed from modyfying ...
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