[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-14] Traveling ionospheric disturbances driven by gravity waves from sources in the upper and lower atmosphere

*Paul Prikryl¹、David R. Themens²、Jaroslav Chum³、Shibaji Chakraborty⁴、Robert G. Gillies⁵、James M. Weygand⁶ (1.Physics Department University of New Brunswick, Fredericton, NB, Canada、2.School of Engineering, University of Birmingham, Birmingham, UK、3.Institute of Atmospheric Physics CAS, Prague, Czech Republic、4.Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA, USA、5.Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada、6.Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA, USA)

キーワード：atmospheric gravity waves, traveling ionospheric disturbances, GNSS total electron content, solar wind Alfvén waves, auroral electrojets, low pressure weather systems

Large- to medium-scale atmospheric gravity waves generated in the upper and lower atmosphere drive traveling ionospheric disturbances (TIDs). The aim of this study is to attribute the observed TIDs to either atmospheric gravity waves generated in the lower thermosphere at high latitudes, or gravity waves generated by tropospheric weather systems at mid latitudes. Equatorward propagating TIDs are observed by the Super Dual Auroral Radar Network (SuperDARN), Poker Flat Incoherent Scatter Radar (PFISR), and using the GNSS total electron content (TEC) mapping technique. Solar wind coupling to the dayside magnetosphere-ionosphere-thermosphere modulating the ionospheric convection and currents, including the intensity of the auroral electrojets, is the source of gravity waves driving equatorward propagating medium to large scale TIDs. The horizontal equivalent ionospheric currents are estimated from the ground-based magnetometer data using an inversion technique. On the other hand, the cases of eastward to southeastward propagating TIDs that are observed in the detrended TEC maps and by the HF Doppler sounders in Czechia are attributed to gravity waves that originate in intensifying low pressure weather systems, most likely generated by geostrophic adjustment processes.