Atmospheric gravity waves generated by solar wind high-speed stream Alfvén waves

<p>Solar wind Alfv&#233;n waves in high-speed streams from coronal holes modulate dayside ionospheric convection and currents, including auroral electrojets [1]. They generate large- to medium-scale atmospheric gravity waves (AGWs) propagating globally from sources in the lower thermosphere both upward and downward [2,3]. In the upper atmosphere, the AGWs drive traveling ionospheric disturbances (TIDs) observed by the Super Dual Auroral Radar Network (SuperDARN), Poker Flat Incoherent Scatter Radar (PFISR), and the GNSS total electron content (TEC) mapping technique. The horizontal equivalent ionospheric currents are estimated from the ground-based magnetometer data using an inversion technique. In the lower atmosphere, the equatorward propagating AGWs with attenuated amplitudes can be amplified upon over-reflection in the troposphere. They can release conditional symmetric instability leading to slantwise convection, latent heat release and intensification of extratropical cyclones [4,5], which in turn are a source of AGWs/TIDs. Southeastward propagating TIDs that originate from cold fronts of intensifying extratropical cyclones are observed in the detrended TEC maps, and by the multipoint and multifrequency continuous Doppler sounders in Czechia. Ray tracing AGWs in a model atmosphere supports the observations.</p> <p>[1] Prikryl P., et al., Ann. Geophys., 40, 619&#8211;639, 2022. doi.org/10.5194/angeo-40-619-2022<br />[2] Mayr H.G., et al., Space Sci. Rev. 54, 297&#8211;375, 1990. doi:10.1007/BF00177800<br />[3] Prikryl, P., et al., Ann. Geophys. 23, 401&#8211;417, 2005. doi.org/10.5194/angeo-23-401-2005<br />[4] Prikryl P., et al., Ann. Geophys. 27, 31&#8211;57, 2009. doi:10.5194/angeo-27-31-2009<br />[5] Prikryl P., et al., J. Atmos. Sol.-Terr. Phys. 171, 94&#8211;10, 2018. doi:10.1016/j.jastp.2017.07.023</p>