Longitudinal distribution of Io's dayside atmospheric density
Researchers used 25 years of mid-infrared observations to map how Io's SO2 atmosphere varies across its longitudes, comparing perihelion and aphelion conditions. The study found significant hemispheric asymmetry in SO2 density, with higher densities near 200W and lower densities near 305W. They concluded that this variability is primarily caused by a combination of the eclipse effect and the inhomogeneity of SO2 surface ice.