Statistical investigation of gravity wave characteristics in the ionosphere

0540569 - ÚFA 2022 RIV DE eng J - Článek v odborném periodiku
Chum, Jaroslav - Podolská, Kateřina - Rusz, Jan - Baše, Jiří - Tedoradze, Nikolai
Statistical investigation of gravity wave characteristics in the ionosphere.
Earth, Planets and Space. Roč. 73, č. 1 (2021), č. článku 60. E-ISSN 1880-5981
Grant CEP: GA ČR(CZ) GA18-01969S
Institucionální podpora: RVO:68378289
Klíčová slova: Travelling ionospheric disturbances * Gravity waves * 3D propagation analysis * Elevation angles of wave vectors * Attenuation of gravity waves * Neutral winds * Wind rest-frame velocities
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 3.362, rok: 2021
Způsob publikování: Open access
https://earth-planets-space.springeropen.com/articles/10.1186/s40623-021-01379-3

Propagation of medium-scale gravity waves (GWs) in the thermosphere/ionosphere is observed remotely, using multi-frequency and multi-point continuous Doppler sounding system located in the western part of Czechia. Reflection heights of the sounding radio waves are determined from a nearby ionosonde. Phase velocity vectors of GWs are calculated from time/phase delays between signals corresponding to different transmitter–receiver pairs that reflect in the ionosphere at different locations. As various frequencies reflect at different heights, reflection points of radio signals are separated both horizontally and vertically, and the investigation of GW propagation in the ionosphere is performed in three dimensions. Results obtained for two 1-year periods representing the solar maximum (July 2014–June 2015) and current solar minimum (September 2018–August 2019) are presented. It is shown that GWs in the ionosphere usually propagated with wave vectors directed obliquely downward. A statistical distribution of wave vector elevation angles is presented. A model of neutral winds is used to estimate the wave characteristics in the wind-rest frame. It is found that the distribution of elevation angles is narrower in the wind-rest frame than in the Earth frame. Seasonal and diurnal changes of propagation directions and attenuations of GWs are discussed. The wind-rest frame wavelengths of the analyzed GWs were usually from ~ 80 to 300 km, and the propagation velocities were mostly between ~ 100 and ~ 220 m/s.
Trvalý link: http://hdl.handle.net/11104/0318215