HR: 1400h
AN: SA33B-02    [Abstracts]
TI: Doppler shift observations of severe tropospheric weather effects in the ionosphere
AU: Sindelarova, T
EM: tersin@ufa.cas.cz
AF: Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Bocni II 1401, Prague, 141 31, Czech Republic
AU: Buresova, D
EM: buresd@ufa.cas.cz
AF: Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Bocni II 1401, Prague, 141 31, Czech Republic
AU: * Lastovicka, J
EM: jla@ufa.cas.cz
AF: Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Bocni II 1401, Prague, 141 31, Czech Republic
AU: Chum, J
EM: jachu@ufa.cas.cz
AF: Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, Bocni II 1401, Prague, 141 31, Czech Republic
AB: Tropospheric severe weather events are regarded as an important natural source of infrasound. They influence the ionosphere through the upward propagating waves. Due to temperature profile in the lower atmosphere, the infrasonic waves are focused upwards and most of the radiated energy can propagate to the upper atmosphere. Detection of infrasonic waves requires sampling in short intervals or preferably continuous measurements. Most of recent instruments for ionospheric sounding cannot detect ionospheric plasma fluctuations in the infrasonic range. The Doppler shift measurements started at the Institute of Atmopheric Physics, Prague in 2004. They enable us to monitor ionospheric wave activity in the acoustic and gravity wave domain. We focus on wave phenomena in the infrasonic range linked to severe tropospheric weather. Here, we compare the impact on the ionosphere of severe weather in summer and in winter. The analysed summer severe tropospheric events were represented by slowly passing cold front, which brought severe convective storms to the monitored region. They were accompanied by tornadoes, supercell development; the observed height of cumulonimbus cloud tops exceeded significantly the height of summer tropopause. As a winter severe weather case, we selected the day with a windstorm and a quickly passing cold front. Due to the fast movement of the frontal surface, convective storms developed on the cold front. Significant gravity wave and infrasonic wave activity was observed during all summer and winter events studied.
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2443 Midlatitude ionosphere
DE: 2487 Wave propagation (0689, 3285, 4275, 4455, 6934)
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly