Tracking SO2 plumes from the Tonga volcano eruption with multi-satellite observations.

The Hunga Tonga-Hunga Ha'apai (HTHH) volcano eruption received worldwide attention due to its magnitude and potential effects on environment and climate. However, the operational sulfur dioxide (SO2) products mis-estimated SO2 emissions under volcanic conditions due to large uncertainties in the assumptions of SO2 plume altitude. That might have occurred in previous volcanic eruptions and misled understanding of the evolution of sulfate aerosols in the atmosphere and their impact on global climate. Here, we simultaneously retrieved the volcanic SO2 and its plume altitude from the Troposphere Monitoring Instrument (TROPOMI) and the Environment Monitoring Instrument-2 (EMI-2), exploring the SO2 burden, distribution, and evolution from January 14 to 17. We captured multiple eruptions with the second eruption emitting far more SO2 than the first. Total emissions exceeded 900 kt, significantly higher than those from operational products. Our inferred emission fluxes and injection heights offer valuable references for climate modeling and submarine volcano studies.