Observations and Modelling of Thermospheric Dynamics at High Latitudes

A strong westward wind pattern in the lower middle thermosphere at high latitudes over both hemispheres, known as a wind wall, is investigated. Since scarce information is available about this region of the atmosphere, model simulations by the WACCM-X model are employed. Model simulations, along with WINDII observations, allowed describing in a great detail most of the wind wall features, as well as its impact on other altitudes and regions. One of the main goals of this study was the determination of the atmospheric circulation pattern linked to the wind wall. Our results indicate that the wind wall is linked to the high latitude convection system. This atmospheric circulation is particularly stronger during active geomagnetic conditions, which results in the origin of the wind wall. The study reveals, the impacts of the wind wall on the dynamics and structure of the lower middle thermosphere, which are mainly a response to the complex high latitude convection system and its time variation.