Journal Article

Mesosphere and Lower Thermosphere Temperature Responses to the May 2024 Mother's Day Storm

Moro, Juliano, Yue, Jia, Liu, Xiao, Xu, Jiyao, Wang, Wenbin

2025

Overview

The storm‐time temperature difference with respect to its quiet‐time expectation (ΔT) in the mesosphere and lower thermosphere were studied during the extreme storms on 2024 Mother's Day and 2003 Halloween Day. The storm‐time ΔT were determined by performing daily zonal running mean on the temperature profiles in the ascending and descending nodes separately. The storm‐time ΔT had peak values of ≥25 K and extended downward to ∼100 km globally. Above 105 km, the global mean ΔT had values of ≥20 K in the early morning and of ≥15 K in the late afternoon during storm‐time. At high latitudes, the storm‐time ΔT was larger in the late afternoon than in the early morning. This is opposite to that at middle and low latitudes. Adiabatic warming/cooling caused by the heating‐induced circulation changes outside of the auroral oval is likely responsible for the local time and latitude dependence of the storm‐time ΔT. Plain Language Summary The storm‐time energy input in the auroral oval plays an important role in changing the dynamics and electrodynamics of the neutral atmosphere and ionosphere. Although the energy input due to Joule and particle heating is the strongest at high latitudes, its influences are global. The mesosphere and lower thermosphere are transition regions between the middle atmosphere and the ionosphere, which are affected by the lower atmosphere, the ionosphere, and the solar and geomagnetic activities. This complicates the physics and dynamical structures of the mesosphere and lower thermosphere during the storm‐time, especially the two extreme storms in the past 20 years. The temperature measured by SABER is used to study the local time and latitude dependence of the storm‐time temperature difference with respect to its quiet‐time expectation. The extreme storms are rare with average occurrence frequency of about 4 days per 11‐year. The storm‐time temperature difference was larger in the late afternoon than in the early morning at high latitudes, which is opposite to that at middle and low latitudes. This highlight that the extreme storms induce much larger and observable temperature changes as compared with those associated tides. Key Points The temperature increased globally and depended on local time during extreme storms on the 2024 Mother's Day and 2003 Halloween Day The storm‐time temperature difference (ΔT) had global means of ≥20 K in the early morning and of ≥15 K in the late afternoon The ΔT is larger in the late afternoon than in the early morning at high latitudes, but the reverse is true at middle and low latitudes

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Adiabatic / Atmosphere / Atmospheric circulation / Auroral oval / Electrodynamics / Extreme weather / Geomagnetic activity / geomagnetic storm / Heating / Ionosphere / Joule heating / Latitude / Lower atmosphere / Lower mantle / Lower thermosphere / meridional circulation / Mesosphere / mesosphere and lower thermosphere / Middle atmosphere / Physics / Storms / Temperature changes / Temperature dependence / Temperature differences / Temperature gradients / Temperature profile / Temperature profiles / thermal structure / Thermosphere / Time dependence / Time measurement