The expectations and prospects for quantitative volcanology in the upcoming SBG era

The Surface Biology and Geology (SBG) mission is part of the National Aeronautics and Space Administration's planned Earth System Observatory. The mid/thermal infrared (MIR/TIR) portion of SBG will deliver high spatial and temporal resolution data designed (in part) to answer fundamental volcano science questions, as outlined in the 2018 Decadal Survey (DS). The planned 60 m spatial resolution, high TIR saturation temperature (∼500 K), and addition of two high temperature MIR bands (∼800–1200 K) will improve thermal feature and spatial variability detection across all volcanic surfaces, as well as limit data saturation over high temperature targets such as lava flows. However, the MIR/TIR part of the mission also has design aspects that will hinder volcanic science. The ability to derive accurate spectral information of volcanic, and indeed other geologic surfaces, is a function of the number and placement of the TIR bands. The originally proposed five TIR bands do not advance these diagnostic investigations beyond what is currently available. In fact, it may hinder them. Six or more TIR bands are vital for accurate assessment of mineral and glass abundances in volcanic deposits. The SBG MIR/TIR mission temporal resolution (3–5 days) will improve repeat coverage of volcanic systems, aiding in longer-term monitoring, but observations of highly dynamic processes will not be possible, despite their importance in the 2018 DS. Most problematic is the proposed local overpass time of 12:30, which will result in cloudier scenes (especially in tropical/lower latitude regions) and complicate atmospheric corrections compared to the traditional morning overpass times of earlier TIR missions.