Investigating MLT response to active geomagnetic conditions using WACCM-X simulations, Wuhan meteor radar and SABER observations

Abstract

The mesosphere and lower thermosphere (MLT), which extends from altitudes of 60 to 120 km, serve as the boundary between Earth’s atmosphere and outer space. This region is challenging to study directly, as it is very challenging to instruments mounted on satellites or balloons. Ground-based tools like radars and lidars offer only limited observations, primarily focused on the neutral atmosphere using electromagnetic waves. This paper delves into how solar storm activity penetrates the MLT region. It examines the neutral wind patterns and background temperature responses during three geomagnetic storms in 2015 and 2003. The research employs numerical simulations utilizing the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X). We analyze the zonal and meridional winds along with temperature changes in the MLT region under both quiet and active geomagnetic conditions. To validate the simulation outcomes, we incorporate neutral wind data gathered from Wuhan meteor radar observations and temperature measurements from the TIMED/SABER satellite. Our findings indicate a distinct signature of the neutral wind’s response to geomagnetic activity. The WACCM-X model prediction of meridional and zonal winds in the MLT region is consistent with the meteor radar observations. We also determine the penetration depth and the percentage of background temperature alteration resulting from active geomagnetic conditions. The alignment of the WACCM-X results with the observational data is encouraging. A data assimilation technique using the WACCM-X model, combined with radar and satellite observations, is proposed to determine the MLT response to active geomagnetic conditions.