Observing Gravity Waves Coupled From Below in Earth's Atmosphere

Atmospheric Gravity Waves (GW) strongly influence the dynamics of Earth's atmosphere, especially in the thermosphere. They do so by depositing momentum, causing drag background mean winds, and perturbing background winds, temperatures, and densities. While there are many sources of GWs such as aurora, mountains, and convection, this study seeks to better understand the source of coupling from below. GW observations over a range of altitudes allow for more insight into GWs sourced by coupling from below. This study investigates several nights in 2018-2019 with high variability observed in the thermosphere by characterizing wave activity in lower regions of the atmosphere. Multiple data sets are used in order to look at these different regions for the same night; these include MERRA-2 reanalysis, Atmospheric Infrared Sounder (AIRS), Rayleigh and sodium lidar, meteor radar, and 630nm measurements from the Scanning Doppler Imager (SDI). Wind speeds and temperature perturbations derived from data from these instruments are the most effective way to determine GW activity. These case studies provide more insight into how waves present in the upper regions of the atmosphere, such as the thermosphere, are sourced by activity occurring below.