Thermal infrared remote sensing of volcanic emissions using the moderate resolution imaging spectroradiometer

The volcanological community has a powerful new tool in the spaceborne moderate resolution imaging spectroradiometer (MODIS), which, from its synoptic perspective, provides satellite imagery of every volcano on Earth every 2 days. MODIS has the spectral characteristics to be able to utilise previously developed retrievals that quantify volcanic ash, ice, sulfates and sulfur dioxide using their thermal infrared (8–12 μm) transmission signature. In this paper, we present a detailed description of the methodologies, based within the thermal infrared region, that are being applied to MODIS data. MODIS data for two eruptions, Hekla, Iceland and Cleveland, Alaska are presented to show results from the ice, ash and SO2 retrieval schemes. We look at current problems with the retrievals used to quantify volcanic emissions, detail recent developments within the field that can be applied to MODIS data, and suggest areas where improvements need to be made in the future.