Anomalous propagation of medium scale GWs along neutral winds

0542504 - ÚFA 2022 DE eng A - Abstract
Rusz, Jan - Chum, Jaroslav - Baše, Jiří
Anomalous propagation of medium scale GWs along neutral winds.
EGU General Assembly 2021 (vEGU21: Gather Online). Göttingen: European Geosciences Union, 2021.
[EGU General Assembly Conference 2021. 19.04.2021-30.04.2021, online]
Institutional support: RVO:68378289
Keywords : ionosphere * thermosphere * medium scale gravity waves * neutral winds
OECD category: Meteorology and atmospheric sciences
https://meetingorganizer.copernicus.org/EGU21/EGU21-4250.html

Azimuth of medium scale gravity waves (GWs) propagation in the thermosphere/ionosphere fundamentally depends on the daytime and day of year. Previous studies show that the GWs mostly propagate against the predominant direction of neutral winds in the ionosphere. However, several cases of propagation along the wind direction have also been identified, specifically around the equinoxes. The analysis is based on remote observation of the ionosphere using multi–frequency and multipoint continuous Doppler sounding. The network consists of at least three spatially separated sounding paths (transmitter-receiver pairs) at three frequencies, situated in the western part of the Czech Republic. The apparent horizontal velocity and azimuth of GWs are derived from the time shifts observed for different measuring paths. The HWM14 neutral wind model is used for comparison of neutral winds with the observed phase speeds of GWs. Cases of anomalous propagation of GWs along the direction of neutral winds are analyzed. It is shown that the observed GW periods can be substantially shorter than the intrinsic periods in the wind-rest frame owing to Doppler shift.
Permanent Link: http://hdl.handle.net/11104/0319902