No (263)
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Dopady lidské činnosti na horní atmosféru
Laštovička, Jan
2010 - Czech
Trendy v teplotě mezosféry, elektronové koncentraci v dolní ionosféře, elektronové koncentraci a výšce jejího maxima v E vrstvě, elektronové koncentraci v maximu F1 vrstvy, hustotě termosféry a iontové teplotě ve vrstvě F kvalitativně souhlasí s následky zesíleného skleníkového efektu a tvoří konzistentní scénář globálních změn v horní atmosféře. Byly identifikovány tři skupiny parametrů, které nezapadají do tohoto scénáře, F2 vrstva ionosféry, vodní pára v mezosféře a dynamika mezosféry a dolní termosféry. V článku je podána informaci o pokroku v globálním scénáři dlouhodobých trendů v horní atmosféře se zaměřením na ty tři otevřené problémy. K dlouhodobým trendům přispívá několik dalších faktorů, jmenovitě antropogenní změny stratosférického ozónu, změny koncentrace vodních par v mezosféře, dlouhodobé změny geomagnetické aktivity a magnetického pole Země Trends in the mesospheric temperature, electron concentration in the lower ionosphere, electron concentration and height of its maximum in the E region, electron concentration in the F1-region maximum, thermospheric neutral density and F-region ion temperature qualitatively agree with consequences of the enhanced greenhouse effect and form a consistent pattern of global change in the upper atmosphere. Three groups of parameters were identified as not-fitting this global pattern, the F2 region ionosphere, mesospheric water vapour, and the mesosphere/lower thermosphere dynamics. The paper reports progress in development of the global pattern of trends with emphasis to these three open problems. There are several other factors contributing to long-term trends, namely the stratospheric ozone depletion, mesospheric water vapour concentration changes, long-term changes of geomagnetic activity and of the Earth’s magnetic field.
Keywords:
Upper atmosphere; long-term trends; human activity
Available at various institutes of the ASCR
Dopady lidské činnosti na horní atmosféru
Trendy v teplotě mezosféry, elektronové koncentraci v dolní ionosféře, elektronové koncentraci a výšce jejího maxima v E vrstvě, elektronové koncentraci v maximu F1 vrstvy, hustotě termosféry a ...
Statistical Study of the Ionospheric Density Variation Related to the 2010 Chile Earthquake and Measured by the DEMETER Satellite
Píša, David; Santolík, Ondřej; Parrot, M.
2010 - English
Statistical Study of the Ionospheric Density Variation Related to the 2010 Chile Earthquake and Measured by the DEMETER Satellite.
Keywords:
Whistler-mode Chorus; Emissions
Available at various institutes of the ASCR
Statistical Study of the Ionospheric Density Variation Related to the 2010 Chile Earthquake and Measured by the DEMETER Satellite
Statistical Study of the Ionospheric Density Variation Related to the 2010 Chile Earthquake and Measured by the DEMETER Satellite.
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 ...
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