The Role of Convectively‐Generated Gravity Waves in Poleward Propagation of MSTIDs Over Srinagar (34.1°N, 74.8°E).

We report the influence of the atmospheric gravity waves on medium scale traveling ionospheric disturbances (MSTIDs) that are observed during the month of September 2020, using an airglow imager over Srinagar, Kashmir. Several cases of nighttime MSTIDs at ∼250 km altitude are presented which propagate either in northwestward, northward or northeastward direction. Either the phase fronts of the observed MSTIDs are not aligned in the NW‐SE direction, or the MSTIDs are not propagating in the southwest direction, these are believed to be non‐electrified MSTIDs which are generally associated with gravity waves (GWs). The average horizontal wavelengths of these MSTIDs range from 185 to 469 km, horizontal phase speeds of about 162–521 m/s while the time periods range from 13 to 24 min considered as very short‐period ionospheric disturbances. The detection of GWs at ∼97 and ∼85 km heights during the nights of MSTID detection leads to the inference that there is a strong correlation between the occurrences of these MSTIDs with mesospheric GWs. By using satellite data, including INSAT‐3DR and the Atmospheric Infrared Sounder, the detection of convective clouds near the locations of the imager is observed, and by utilizing the kinetic temperature data from the Sounding of the Atmosphere using Broadband Emission Radiometry satellite, the presence of GWs near the convective systems is also seen. Such GWs are also observed in the vicinity of the imager location and it is concluded that the lower atmospheric convectively‐generated GWs could be a leading factor for the generation of poleward propagating MSTIDs. Plain Language Summary: The atmospheric gravity waves generally impact on some specific types of disturbances in the Earth's ionosphere known as medium‐scale traveling ionospheric disturbances (MSTIDs) although there are several other electrodynamic factors responsible for their generation. Using a specialized instrument called as all‐sky airglow imager over an Indian subtropical region (Srinagar), we identified several instances of nighttime MSTIDs occurring at a height of ∼250 km above the Earth's surface traveling in different directions, such as northwestward, northward, or northeastward which otherwise propagate southwestward over the Northern Hemisphere in general. So, the observed class of the MSTIDs is not consistent with the electrified ones and can instead be associated with atmospheric gravity waves (GWs). The appearance of GWs at the mesospheric heights and even in the lower atmospheric heights suggests a strong connection between the occurrence of MSTIDs and mesospheric GWs. This study used data from airglow imager, satellites like Sounding of the Atmosphere using Broadband Emission Radiometry, INSAT‐3DR and Atmospheric Infrared Sounder to reveal the relationships between the ionospheric disturbances and convectively generated GWs. Hence, we concluded that GWs originating in the lower atmosphere due to convective processes play a significant role in generating poleward propagating MSTIDs which indicates that the GW propagation plays a significant role in the troposphere‐ionosphere coupling. Key Points: The study identifies the poleward propagating non‐electrified nighttime medium scale traveling ionospheric disturbances (MSTIDs) that don't align along the typical NW‐SE directionPresence of mesospheric gravity waves (GWs) during the nights of MSTID detection indicate a strong link between the GWs and non‐electrified MSTIDsLower atmospheric convection believed to be a prominent factor of generation of poleward propagating MSTIDs indicative of Troposphere‐Ionosphere Coupling [ABSTRACT FROM AUTHOR]