J. Baše
Academy of Sciences of the Czech Republic
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Publication
Featured researches published by J. Baše.
Journal of Geophysical Research | 2014
Jaroslav Chum; F. A. M. Bonomi; Jiří Fišer; M.A. Cabrera; R.G. Ezquer; Dalja Buresova; Jan Lastovicka; J. Baše; F. Hruška; María G. Molina; J. E. Ise; J. I. Cangemi; T. Šindelářová
Results of systematic analysis of propagation directions and horizontal velocities of gravity waves (GWs) and spread F structures in low-latitude ionosphere (magnetic inclination ~27°) in Tucuman region, Argentina, are presented. Measurements were carried out by multipoint continuous Doppler system during 1 year from December 2012 to November 2013. It was found that meridian propagation of GWs dominated and that southward propagation prevailed in the local summer. Oblique spread structures observed in Doppler shift spectrograms and associated with spread F propagated roughly eastward at velocities from ~70 to ~180 m/s and were observed at night from ~ September to ~ March. The velocities were computed for 182 events and the azimuths for 64 events. Continuous Doppler sounding makes it possible to analyze more events compared to optical observations often used for propagation studies since the measurements do not depend on weather.
Journal of Geophysical Research | 2016
Jaroslav Chum; M.A. Cabrera; Zbysek Mosna; M. Fagre; J. Baše; Jiří Fišer
The nonlinear behavior of acoustic waves and their dissipation in the upper atmosphere is studied on the example of infrasound waves generated by vertical motion of the ground surface during the Mw 8.3 earthquake that occurred about 46 km from Illapel, Chile on September 16, 2015. To conserve energy, the amplitude of infrasound waves initially increased as the waves propagated upwards to the rarefied air. When the velocities of air particles became comparable with the local sound speed, the nonlinear effects started to play an important role. Consequently, the shape of waveform changed significantly with increasing height, and the original wave packet transformed to the “N-shaped” pulse resembling a shock wave. A unique observation by the continuous Doppler sounder at the altitude of about 195 km is in a good agreement with full wave numerical simulation that uses as an input the measured vertical motion of the ground surface.
Earth, Planets and Space | 2016
Jaroslav Chum; Jann-Yenq Liu; Jan Lastovicka; Jiří Fišer; Zbysek Mosna; J. Baše; Yang-Yi Sun
Journal of Geophysical Research | 2010
Jaroslav Chum; T. Šindelářová; Jan Lastovicka; F. Hruška; Dalja Buresova; J. Baše
Journal of Geophysical Research | 2012
Jaroslav Chum; R. Athieno; J. Baše; Dalja Buresova; F. Hruška; Jan Lastovicka; Lee-Anne McKinnell; T. Šindelářová
Journal of Atmospheric and Solar-Terrestrial Physics | 2010
Jan Lastovicka; J. Baše; F. Hruška; Jaroslav Chum; T. Šindelářová; J. Horálek; Jan Zedník; V.M. Krasnov
Journal of Geophysical Research | 2013
Jaroslav Chum; G. Diendorfer; T. Šindelářová; J. Baše; F. Hruška
Earth, Planets and Space | 2016
Jaroslav Chum; Jann-Yenq Liu; Shih Ping Chen; M.A. Cabrera; Jan Lastovicka; J. Baše; Dalia Buresova; Jiří Fišer; F. Hruška; R.G. Ezquer
Journal of Atmospheric and Solar-Terrestrial Physics | 2015
Tereza Sindelarova; Jaroslav Chum; K. Skripnikova; J. Baše
Advances in Space Research | 2018
Tereza Sindelarova; Zbysek Mosna; Jaroslav Chum; Daniel Kouba; J. Baše; J. Y. Liu; Zama T. Katamzi-Joseph