Temporal evolution of nightglow emission responses to SSW events observed by TIMED/SABER

Using the SSW (Stratospheric Sudden Warming) event in 2009 as a representative case, the temporal evolution of the responses of OH and O₂ infrared atmospheric (0-0) nightglow emissions to SSW events is analyzed using the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics)/SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) data. The results show that during the mesospheric cooling that occurs during the stratospheric warming stage of SSW events, the brightness of OH and O₂ nightglow emissions and the thicknesses of OH and O2 emission layers decrease noticeably and the peak heights of the emissions ascend. During the recovery stage in the mesosphere, the brightness of both nightglow emissions and the thicknesses of the emission layers increase dramatically and the peak heights of the emissions descend. These emission variations are mainly caused by perturbations in temperature and the transport of O in the MLT (Mesosphere Lower Thermosphere) region. For the SSW event that started in January 2009, the onset times of the cooling stage and recovery stage in the mesosphere are ∼2 days ahead of the onset times of the warming stage and recovery stage of the SSW event, respectively. For this event, the influence of the SSW on the OH and O₂ nightglow emissions increases with latitude between 50°N and 80°N.