Using the GOES Sounder to monitor upper level SO2 from volcanic eruptions

Abstract

This study explores the sensitivity of the Geostationary Operational Environmental Satellite (GOES) Sounder observations to atmospheric loadings of SO2.from volcanic eruptions. The GOES Sounder offers a more rapid refresh rate than similar instruments on board polar‐orbiting satellites, such as the High‐Resolution Infrared Radiation Sounder (HIRS) carried on the NOAA and MetOp spacecraft. One of the GOES Sounder's 19 channels is in an SO2 absorption band. Simulations demonstrate that this channel, centered at approximately 7.4 mm, when combined with other channels, can detect the presence of large amounts of SO2 (e.g., greater than 50 DU) in the upper atmosphere (e.g., above 8 km). The GOES Sounder can also provide upper limits of the amount of upper level SO2, provided the atmospheric altitude of the SO2 is known. The sensitivity is demonstrated on two volcanic eruptions of the Soufrière Hills Volcano on the island of Montserrat. Through use of the GOES Sounder measurements, the advection and rapid spreading of the plume are easily observed. Efforts to fully characterize the plume size and transport are hampered by the limited spatial coverage of the current GOES Sounder.