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Estimation of the Apparent Source Size of Solar Radio Emissions Using SVD: An Application to Type III Radio Bursts at Long Wavelengths Observed by STEREO and Wind
Krupař, Vratislav; Santolík, Ondřej; Cecconi, B.; Maksimovic, M.
2010 - English
Type III radio bursts are intense solar radio emissions. They are frequently observed by the S/Waves instruments on-board the STEREO spacecraft. We describe a wave propagation analysis using the Singular Value Decomposition (SVD) which can be directly applied to spectral matrices measured by the High Frequency Receiver (HFR; a part of the S/Waves experiment). We have found an empirical relation between the decomposed spectral matrices and apparent source sizes for waves with a low degree of polarization. We present a joint observation of a type III radio burst by the STEREO and Wind spacecraft during small separation distances. We obtain consistent results for the apparent source size and k-vector direction using different analysis method for the measurements of the STEREO and Wind spacecraft. We demonstrate that SVD can be an effective tool for the wave analysis of radio emissions with very extended sources.
Keywords:
Solar Radio; SVD; Wavelengths; STEREO
Available at various institutes of the ASCR
Estimation of the Apparent Source Size of Solar Radio Emissions Using SVD: An Application to Type III Radio Bursts at Long Wavelengths Observed by STEREO and Wind
Type III radio bursts are intense solar radio emissions. They are frequently observed by the S/Waves instruments on-board the STEREO spacecraft. We describe a wave propagation analysis using the ...
Different Spectral Shapes of Whistler-mode Chorus Emissions
Macúšová, Eva; Santolík, Ondřej
2010 - English
Different Spectral Shapes of Whistler-mode Chorus Emissions are presented here.
Keywords:
Whistler-mode Chorus; Emissions
Available at various institutes of the ASCR
Different Spectral Shapes of Whistler-mode Chorus Emissions
Different Spectral Shapes of Whistler-mode Chorus Emissions are presented here.
Study of Chance for Good DDA Drift Velocity Estimation for Ionospheric F-region Drift Measurements
Kouba, Daniel; Koucká Knížová, Petra
2010 - English
Estimation of the plasma drift velocity measured by Digisonde depends on the number of reflection points and their distribution. In the paper we divide and analyse plasma drift measurements according to the number of reflection points. A detailed study of Digisonde drift measurement quality has not been published yet. Two extreme groups are selected for further detail analysis, the first one with less than 100 reflection points and the second with more than 800 points. Within the data in these groups we detect annular and diurnal variability. Measurements containing low number of the reflection points occur mainly around equinoxes and during day-time. On the contrary, maximum occurrence of the measurements with more than 800 points is in winter and summer. The lowest chance to register extreme number of the reflections is during afternoon and around sunset.
Keywords:
Drift Velocity; DDA; Estimation; F-region
Available at various institutes of the ASCR
Study of Chance for Good DDA Drift Velocity Estimation for Ionospheric F-region Drift Measurements
Estimation of the plasma drift velocity measured by Digisonde depends on the number of reflection points and their distribution. In the paper we divide and analyse plasma drift measurements according ...
Aplikovaný výzkum atmosféry v ÚFA AV ČR,v.v.i
Fišer, Ondřej; Jaroš, J.; Brázda, V.
2009 - Czech
This article describes the research performed at the Milesovka observatory. The base of this research is the measurement of the signal attenuation on the experimental free space optic link. Concurrently the pertinent meteorological parameters are measured and compared to the attenuation. First of all, visibility, liquid water content, wind speed + other wind parameters and rain rate are sampled and statistically evaluated including diurnal variations.
Keywords:
Free-space optics link; atmospheric attenuation; meteorological parameters; experimental aktivity
Available at various institutes of the ASCR
Aplikovaný výzkum atmosféry v ÚFA AV ČR,v.v.i
This article describes the research performed at the Milesovka observatory. The base of this research is the measurement of the signal attenuation on the experimental free space optic link. ...
Calibration of the STEREO/WAVES Instrument in the Solar Wind
Krupař, Vratislav; Maksimovic, M.; Cecconi, B.; Santolík, Ondřej
2009 - English
The S/WAVES instrument onboard the STEREO spacecraft measures electromagnetic waves in the solar wind. This unique project allows us to investigate properties of type II and type III radio bursts related with solar flares and propagation of coronal mass ejections (CMEs) in the interplanetary medium, respectively. In this paper we present properties of the High Frequency Receiver (HFR) receiver which covers the frequency range 125 kHz–16.025 MHz. We have compared the gains from the two HFR channels and we have found significant variations of these gains with time. We have proposed a solution for correcting these gain variations and improving the S/WAVES HFR calibrations in order to get as accurate goniopolarimetric measurements as possible.
Keywords:
Solar Radio Emissions; Goniopolarimetric inversion
Available at various institutes of the ASCR
Calibration of the STEREO/WAVES Instrument in the Solar Wind
The S/WAVES instrument onboard the STEREO spacecraft measures electromagnetic waves in the solar wind. This unique project allows us to investigate properties of type II and type III radio bursts ...
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 ...
Vlivy sluneční a geomagnetické aktivity na výskyt synoptických situací
Huth, Radan; Kyselý, Jan; Bochníček, Josef; Hejda, Pavel
2008 - Czech
Zimní měsíce jsou rozděleny do tří tříd podle průměrné měsíční hodnoty slunečního toku F10.7. V každé třídě počítáme četnosti výskytu skupin synoptických typů Hesse-Brezowského. Winter months are divided into three classes according to the mean monthly solar F10.7 flux. Within each class, frequencies of occurrence of groups of Hess-Brezowsky synoptic types are calculated.
Keywords:
solar activity; atmospheric circulation; solar-terrestrial relationships; circulation types
Available at various institutes of the ASCR
Vlivy sluneční a geomagnetické aktivity na výskyt synoptických situací
Zimní měsíce jsou rozděleny do tří tříd podle průměrné měsíční hodnoty slunečního toku F10.7. V každé třídě počítáme četnosti výskytu skupin synoptických typů Hesse-Brezowského....
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