Horizontal velocities and propagation directions of gravity waves in the ionosphere over the Czech Republic

0350501 - ÚFA 2011 RIV US eng J - Journal Article
Chum, Jaroslav - Šindelářová, Tereza - Laštovička, Jan - Hruška, František - Burešová, Dalia - Baše, Jiří
Horizontal velocities and propagation directions of gravity waves in the ionosphere over the Czech Republic.
Journal of Geophysical Research. Roč. 115, - (2010), A11322/1-A11322/13. ISSN 0148-0227
R&D Projects: GA ČR GA205/07/1367; GA ČR GA205/09/1253
Grant - others:AV ČR(CZ) M100420901
Institutional research plan: CEZ:AV0Z30420517
Keywords : Ionosphere * gravity waves * wave propagation * remote sensing
Subject RIV: BL - Plasma and Gas Discharge Physics
Impact factor: 3.303, year: 2010

Using a five-point continuous Doppler sounding system operating at 3.59 MHz we investigate propagation directions and velocities of gravity waves (GWs) at altitudes from ~150 to ~250 km over the western part of the Czech Republic. The velocities and directions are computed from the time delays between the observations of corresponding GWs at different reflection points that correspond to various sounding paths. We focused on the GWs that produce an S-shaped trace in Doppler shift spectrograms and are observed close to sunrise and sunset. We have selected about 100 of such events. Our results show that the analyzed GWs propagate with typical horizontal velocities from ~100 to ~200 m/s. The north-south component of GW velocities depends on the season, it is directed northward in the summer and southward in the winter. At the same time, the north-south component of the neutral winds calculated by the horizontal wind model HWM07 has the opposite sign.
Permanent Link: http://hdl.handle.net/11104/0190492