Inversion of O21.27 μm nightglow emissions: A climatological analysis using satellite Limb-Viewed spectra and Harmonic analysis method

This study employs a linear inversion algorithm to retrieve volume emission rates (VERs) of molecular O2 nightglow at 1.27 μm, utilizing Limb-Viewed spectra obtained from the SCanning Imaging Absorption spectroMeter for Atmospheric for CHartographY (SCIAMACHY) payload on board the Envisat satellite. The retrieved results are compared with VERs data from the SABER payload on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite, exhibiting consistency. This will help to facilitate accurate revelation of spatial distribution and periodic variation in O2 nightglow. VERs are extracted monthly within the altitude range of 75−110 km from 2002 to 2012, yielding a climatology of spatial and temporal distributions. The meridional structure exhibits two maxima, at the equator and at 45°N. Between August and October, the VERs exhibit a meridional bimodal structure, with the weaker one above the equator and the stronger one above 45°N. In April, the VERs reach their annual maximum. Additionally, harmonic analysis reveals significant temporal variations on different scales. The emission shows characteristics of annual and semi-annual variation, and a non-linear long-term trend associated with solar cycle activity.