Observations and Modeling of Strong Thermospheric Winds at High Latitudes and Their Impact on the Lower Thermosphere

Abstract

A strong westward wind pattern at altitudes of ∼140–250 km at high latitudes (∼65°) in the approximate longitude range of 100°E–200°E in the Southern Hemisphere, and from 200°E to 300°E in the Northern Hemisphere, known as a “wind wall,” is investigated. Simulations from the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM‐X) and the Global Airglow (GLOW) model, along with Wind Imaging Interferometer (WINDII) observations, allowed the description of most of the wind wall features. The results indicate that the wind wall is linked to the well‐known high‐latitude wind convection pattern. This atmospheric circulation is significantly stronger during active geomagnetic conditions, where its dusk anticyclonic circulation cell is also enhanced, which results in the origin of the wind wall. The study also reveals the impacts of the wind wall on the vertical velocity and its consequences for the O(1S) green line emission on the lower thermosphere, as well as its influence on the atomic oxygen depletion at high latitudes, which is mainly a response to the complex high‐latitude wind convection pattern and its spatial and temporal variation.

IMF Dependence of Midnight Bifurcation in the Thermospheric Wind at an Auroral Latitude Based on Nine Winter Measurements in Tromsø, Norway

“…Consequently, at high latitudes, traces of ionospheric plasma convection are seen everywhere in the thermosphere. For example, westward thermospheric wind can often be observed in the dusk sector at auroral latitudes, where westward ion drag acts against the background eastward thermospheric wind (Barreto‐Schuler et al., 2021; Cai et al., 2019; Conde et al., 2001; Oyama et al., 2022, 2023; Wang, Lühr, & Ma, 2012b; Wang, Lühr, Ritter, & Kervalishvili, 2012; Wang et al., 2018; Xu et al., 2019).…”