Seasonal Variations of Medium‐Scale Waves Observed by ICON‐MIGHTI

Abstract

AbstractThis work presents an analysis of seasonal variations of medium‐scale perturbations (∼500 to ∼5,700 km) spanning altitudes from 90 to 250 km using temperature and wind measurements made by the Michelson Interferometer for Global High‐resolution Thermospheric Imaging (MIGHTI) instrument onboard the Ionospheric Connection Explorer (ICON) in the latitude range of 0°–40°N during 2020–2021. Both medium‐scale perturbations (MSP) in temperature and winds below ∼120 km show semi‐annual variations, whereas annual variations of MSP for winds become dominant between 160 and 250 km. The largest wind MSP was observed at ∼110–120 km throughout the year. Spatial variations of MSP at 90–250 km do not show clear geographic patterns in either temperature or wind. Our analysis suggests both seasonal variations of MSP between 90 and 250 km altitudes are influenced by variation on both the sources of MSP and changes in the background wind.