Io's colorful appearance and unusual thermal emission have made it an object of interest for solar system astronomers for decades. Only recently have we become aware of the intimate connections between the tenuous atmosphere, the vibrant surface and the violent volcanic eruptions on this small moon. This work presents a series of studies which illuminate these three areas. Specifically, we found that there is a substantial time variability to the sulfur monoxide content of Io's atmosphere, and that the measured rotational temperature of the gas (550-1000K) implies a volcanic origin.

We then focused on Io's volcanism during a serendipitous discovery of a major volcanic outburst at Tvashtar Catena. The OSIRIS instrument allowed us unprecedented spatial and spectral resolution, which we used to pinpoint the location of the outburst to 59 ± 1N, 121 ± 1W. With the H and K band spectra we determined a temperature of 1240 ± 4K with a surface emitting area of 57 ± 6km².

Finally we studied Io's surface through mapping the coverage of sulfur dioxide ice. Both low and high spatial resolution data displayed a largely equatorial distribution of ice, consistent with early studies by the Voyager and Galileo spacecraft. Importantly these results differ from some of the recent findings. We present, however, a potential unifying theory to explain this discrepancy, which may answer the long-standing question of the location of Io's ice.

Included in the final chapter is further discussion of some of the technical challenges faced in this research, specifically with the OSIRIS instrument and the solid surface models used to interpret the sulfur dioxide ice data.