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The STEREO/Waves Goniopolarimetric Products for Centre de Données de la Physique des Plasmas
Krupař, Vratislav; Cecconi, B.; Maksimovic, M.; Nguyen, Q. N.; Santolík, Ondřej
2011 - anglický
We present results on the calibration of the HFR receiver, a part of the S/Waves instrument onboard the STEREO spacecraft. The HFR provides us with GP measurements in the frequency range 125–1975 kHz. The obtained data products will be archived in the Plasma Physics Data Center: CDPP. This paper contains a description of used methods and summarizes outputs of the calibration.
Klíčová slova:
Solar Radio Emissions; Goniopolarimetric inversion
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
The STEREO/Waves Goniopolarimetric Products for Centre de Données de la Physique des Plasmas
We present results on the calibration of the HFR receiver, a part of the S/Waves instrument onboard the STEREO spacecraft. The HFR provides us with GP measurements in the frequency range 125–1975 ...
Vliv dešťových srážek na koncentraci prachu v ovzduší
Fišák, Jaroslav; Bartůňková, Kristýna
2011 - český
V tomto příspěvku je pozornost věnována vlivu srážek na množství prachu v ovzduší. Jsou použity dvě charakteristiky srážek: srážkový úhrn a doba trvání srážek. Pro stanovení koncentrace prachu v ovzduší je využita suchá filtrovací metoda, kdy byl vzduch nasáván vývěvou přes hlavici s filtrem. Expozice filtru byla cca 1 týden. Doba odběru vzorků nebyla zcela konstantní. Proto bylo nutno přistoupit na relativní charakteristiky. Zvolen byl srážkový úhrn připadající na 1 den expozice filtru. Ještě složitější bylo charakterizovat dobu trvání srážek. Zde bylo zvoleno procentuální vyjádření doby trvání srážek vzhledem k době expozice filtru. Bylo zjištěno, že v období, kdy se vyskytují jen kapalné srážky, je koncentrace prachu v ovzduší silně ovlivněna jejich výskytem. Lze předpokládat, že část prachu je zachycena vodními kapičkami. Část prachu se do ovzduší vůbec nedostane. S růstem doby trvání i množství srážek klesá koncentrace prachu v ovzduší. In this contribution the impact of precipitation on the amount of dust in the air is studied. Two precipitation characteristics are used: precipitation amount and time of precipitation duration. For the determination of dust concentrations dry filtering method was used. By this method the air is being sucked in by the suction pump over the head with filter. The exposition of the filter lasted approximately one weak. The time of samples collecting was not absolutely constant. Therefore it was necessary to choose relative characteristics. Precipitation amount for daily exposition of the filter was used. Even more difficult was to characterize the time of precipitation duration. In this case percent expression of precipitation duration to the time of filter exposition was used.
Klíčová slova:
dust in the air; precipitation amount; time of precipitation duration
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Vliv dešťových srážek na koncentraci prachu v ovzduší
V tomto příspěvku je pozornost věnována vlivu srážek na množství prachu v ovzduší. Jsou použity dvě charakteristiky srážek: srážkový úhrn a doba trvání srážek. Pro stanovení koncentrace prachu v ...
Influence of Non-vertical Echoes to Ionogram Scaling
Kouba, Daniel; Koucká Knížová, Petra
2011 - anglický
Digisonde DPS 4 replaced the older ionosonde IPS 42 KEL Aerospace in the Observatory Pruhonice in January 2004. Additional information about the wave polarization enables us to determine and to distinguish exactly between ordinary and extraordinary wave traces on the ionogram records. This new ability basically changes scaling of the ionograms comparing to the ionograms obtained by classical ionosondes. Digisonde measurements show that in some cases the interpretation of ionograms based on classical ionospheric soundings may lead to the systematic errors, which affect classical ionograms interpretation. We demonstrate possible significant misinterpretations of the ionograms obtained using the classical equipment that is not able to distinguish between ordinary and extraordinary modes and records only time of flight of the electromagnetic sounding pulse. We show the necessity to be careful in using an old ionosonde measurements and scaled data for further analysis.
Klíčová slova:
Digisonde; ionogram interpretation; spread F
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Influence of Non-vertical Echoes to Ionogram Scaling
Digisonde DPS 4 replaced the older ionosonde IPS 42 KEL Aerospace in the Observatory Pruhonice in January 2004. Additional information about the wave polarization enables us to determine and to ...
Evaluating drought risk for permanent grasslands under present and future climate conditions
Trnka, Miroslav; Schaumberger, A.; Formayer, H.; Eitzinger, Josef; Hlavinka, Petr; Semerádová, Daniela; Dubrovský, Martin; Možný, M.; Thaler, S.; Žalud, Zdeněk
2011 - anglický
Over the past years, the changing climate has affected parts of Czech Republic and Austria by drought spells of the intensity and extend that was unprecedented in previous decades. These events had a significant impact on agricultural areas, especially on the grasslands. The idea behind the GIS monitoring relies on hypothesis that the effect of weather and climate conditions on the grassland production can be estimated by models that describe certain natural processes in a simplified manner and in spatialized form.
Klíčová slova:
climatic change; drouhgt stress; grasslands; modelling; yield
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Evaluating drought risk for permanent grasslands under present and future climate conditions
Over the past years, the changing climate has affected parts of Czech Republic and Austria by drought spells of the intensity and extend that was unprecedented in previous decades. These events had a ...
Statistical analysis of equatorial noise emissions as a function of magnetic local time
Hrbáčková, Zuzana; Němec, F.; Santolík, Ondřej
2011 - anglický
The four spacecraft of the Cluster mission collect a unique data set since January 2001. We process the time period from January 2001 to December 2009. The spacecraft changed their orbits over the last few years, resulting in the data set with excellent coverage of a wide range of radial distances from the Earth, especially in the equatorial plane. We focus on the statistical analysis of whistler-mode waves called the equatorial noise (EN). These intense wave emissions are generated by unstable ion distributions. They propagate close to the geomagnetic equator at frequencies between the local proton cyclotron frequency and the lower hybrid frequency. Polarization of the magnetic field fluctuations corresponding to these emissions is linear. We processed data from the STAFF-SA instruments which preanalyze data from electric and magnetic field fluctuations onboard and provide us hermitian spectral matrices. We use the data measured at radial distances from about 2 to 11 RE to show the dependence of the occurrence of EN on the magnetic local time (MLT). We show from the statistical analysis that EN is occurred at all research radial distances within 10◦ from the geomagnetic equator and the maximum occurrence rate of EN is during the daytime especially in the afternoon sector.
Klíčová slova:
Cluster spacecraft; Earth's magnetosphere; equatorial noise emission
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Statistical analysis of equatorial noise emissions as a function of magnetic local time
The four spacecraft of the Cluster mission collect a unique data set since January 2001. We process the time period from January 2001 to December 2009. The spacecraft changed their orbits over the ...
Models of FSO link attenuation due to fog, rain and wind derived from measurement
Fišer, Ondřej; Brázda, Vladimír; Chládová, Zuzana; Pešice, Petr; Svoboda, Jaroslav; Schejbal, V.
2011 - anglický
The Institute of Atmospheric Physics of the Czech Academy measures atmospheric attenuation on 60 m experimental FSO link while wavelength being 830 and 1550 nm. The measurement lasts three years. In this contribution we show dependences of FSO link attenuation on visibility, rain rate and selected wind parameters. We show that the measured attenuation values are higher than the theoretical values derived by the Kim formula. The sonic temperature is surprisingly very well correlated with attenuation.
Klíčová slova:
Free-space optics; atmospheric attenuation; visibility; rain rate; wind parameters; sonic temperature
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Models of FSO link attenuation due to fog, rain and wind derived from measurement
The Institute of Atmospheric Physics of the Czech Academy measures atmospheric attenuation on 60 m experimental FSO link while wavelength being 830 and 1550 nm. The measurement lasts three years. In ...
The insoluble particles in water deposited from fog at Milešovka Observatory (Czech Republic)
Bartůňková, Kristýna; Fišák, Jaroslav; Stoyanova, V.; Schoumkova, A.
2011 - anglický
This study concerns insoluble chemical pollution of fog at Milešovka Observatory in the Czech Republic. In period from August 2006 till July 2007, 25 fog samples at the top of Milešovka Mountain in České Středohoří Mountains were collected by active fog water collector. Water samples were filtered. From 53 to 116 particles from every sample were chosen according to the quantity of particles found in dried filters. Altogether it was more than 2000 particles. Particles were examined with the help of Scanning Electron Microscope and Energy Dispersive X-Ray Spectrometer to distinguish sizes, shapes and composition. After analyzing the data, statistical evaluation was made. Particles were put into categories according to their shapes on spherical and not spherical. Typical particles like Al, Si, K, Fe or Ca-rich particles were determined. Focus was also to particles with rarely represented elements like Ni, Au, Pb, Cu, Zr and Ba. Groups of typical insoluble particles were collated according to meteorological conditions - synoptic situations and wind directions which prevailed in the days of fog events in order to try to find out possible sources of this fog pollution.
Klíčová slova:
Insoluble particles; Scanning Electron Microscope; fog water
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
The insoluble particles in water deposited from fog at Milešovka Observatory (Czech Republic)
This study concerns insoluble chemical pollution of fog at Milešovka Observatory in the Czech Republic. In period from August 2006 till July 2007, 25 fog samples at the top of Milešovka Mountain in ...
Scaling Analysis Applied to Ionospheric, Solar and Geomagnetic Data
Mošna, Zbyšek; Koucká Knížová, Petra
2011 - anglický
Scaling analysis based on structure function zeta(q) computed using wavelet analysis and spectrum D(h) is used to study possible connection of ionospheric system with the solar and geomagnetic activity. Data from six ionospheric stations (critical frequency foF2), solar flux F10.7 and geomagnetic indices AE, Kp and Dst are used. Data of foF2 show scale invariance in the period range 2–32 day. Scaling properties of ionospheric data show strong dependence on geomagnetic latitude of the station. Similar distribution of values of scaling exponents h for ionospheric and geomagnetic activity AE and Kp suggests connection between these systems. Values of h for foF2 and F10.7 have different distribution which suggests weak connection between these systems at chosen periods.
Klíčová slova:
Scaling analysis; structure function; ionosphere; critical frequencies
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Scaling Analysis Applied to Ionospheric, Solar and Geomagnetic Data
Scaling analysis based on structure function zeta(q) computed using wavelet analysis and spectrum D(h) is used to study possible connection of ionospheric system with the solar and geomagnetic ...
Automatic Visualization Method of Height–Time Development of Ionospheric Layers
Mošna, Zbyšek; Koucká Knížová, Petra
2010 - anglický
An automatic method for visualization of variability of ionospheric plasma in terms of ionospheric layers is presented. Here, we use the virtual reflection height for visualization. We directly plot the height–time dependence using original raw digisonde outputs. It gives us an opportunity to promptly visualise the ionospheric digital data and locate events of the interest for further analysis. In this paper, we present a variability in height of E-layer with a special focus on the sporadic E-layer. The proposed method is applicable for any ionospheric region.
Klíčová slova:
Ionospheric Layers; Visualization
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Automatic Visualization Method of Height–Time Development of Ionospheric Layers
An automatic method for visualization of variability of ionospheric plasma in terms of ionospheric layers is presented. Here, we use the virtual reflection height for visualization. We directly plot ...
Systematic Analysis of Equatorial Noise Using Data of the Cluster Mission
Hrbáčková, Zuzana
2010 - anglický
The four spacecraft of the Cluster mission are collecting a unique data set. We use data measured between 2002 and 2009. These data are unique not only by their quantity but also because the spacecraft changed their orbits during their operational phase and therefore we have data from a large area around the Earth. We focus our analysis on observations of equatorial noise (EN) which is an intense electromagnetic emission generated by unstable ion distributions. It occurs in the inner magnetosphere and propagates close to the geomagnetic equator between the local proton cyclotron frequency and local lower hybrid frequency. We make systematic analysis of EN using data from the STAFF-SA instruments onboard the four spacecraft of the Cluster mission.
Klíčová slova:
Analysis; Equatorial Noise; Cluster Mission
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Systematic Analysis of Equatorial Noise Using Data of the Cluster Mission
The four spacecraft of the Cluster mission are collecting a unique data set. We use data measured between 2002 and 2009. These data are unique not only by their quantity but also because the ...
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