Solar UV flux in relation to airglow variability as seen by MATS

Solar activity, including variations in solar radiation and transient disturbances in the solar wind, drives a variety of processes in Earth's atmosphere. Solar ultraviolet (UV) radiation provides the primary energy input to the mesosphere and lower thermosphere, while enhanced solar wind plasma and magnetic field variations can indirectly influence atmospheric dynamics through magnetospheric coupling. These processes lead to atmospheric emissions observed as airglow and, at higher latitudes, aurorae.

MATS (Mesospheric Airglow/Aerosol Tomography and Spectroscopy) provides an opportunity to study the mesospheric infrared O₂ A-Band emission, whose variability and excitation mechanisms are not yet fully understood. Using MATS observations from February to May 2023, we extract time series of airglow brightness variations in the mesosphere. To characterize solar activity, we use solar UV flux measurements from NASA's SDO/EVE and TIMED/SEE instruments.

In addition, we examine the occurrence of coronal mass ejections and co-rotating interaction regions during the study period to assess their potential contribution to the observed variability. We present correlations between MATS airglow brightness, solar UV irradiance, and solar wind parameters to quantify the relative roles of radiative and geomagnetic drivers.