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

Abstract

AbstractWe 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.