Mesoscale stereo retrievals from Hunga Tonga-Hunga Ha'apai Eruption of 15 January 2022

Stereo methods using GOES-17 and Himawari-8 applied to the Hunga Tonga-Hunga Ha'apai volcanic plume on 15 January 2022 show overshooting tops reaching 50-55 km altitude, a record in the satellite era.  Plume height is important to understand dispersal and transport in the stratosphere and climate impacts.  Stereo methods, using geostationary satellite pairs, offer the ability to accurately capture the evolution of plume top morphology quasi-continuously over long periods.  Manual photogrammetry estimates plume height during the most dynamic early phase of the eruption and a fully automated algorithm retrieves both plume height and advection every 10 minutes during a more frequently sampled and stable phase beginning three hours after the eruption.  Stereo heights are confirmed with Global Navigation Satellite System Radio Occultation (GNSS-RO) bending angles, showing that much of the plume was lofted 30–40 km into the atmosphere. Cold bubbles are observed in the stratosphere with brightness temperature of ~173K.