| 07 Oct 2026
A full-mission TROPOMI SO2 height dataset: enhanced sensitivity to low-altitude plumes and complementarity with IASI and PlumeTraj
Abstract. Information on sulfur dioxide (SO2) plume altitude is crucial for understanding volcanic events and their atmospheric and climatic impacts, constraining satellite SO2 data, and improving aviation safety. While SO2 column-density records have been routinely derived from UV nadir sensors for decades, plume-height retrievals remain challenging and have largely been limited to volcanic eruptions with relatively high SO2 loadings. Here, we present the first global SO2 plume-height dataset derived from the second UV spectral band of the TROPOspheric Monitoring Instrument (TROPOMI), covering 2018–2025. Building on our previous work (Fabris et al., 2026), retrievals were performed using an optimised implementation of the Look-Up Table Covariance-Based Retrieval Algorithm (LUT-COBRA), providing good sensitivity to low SO2 amounts and a wide range of plume heights. We analyse global and regional SO2 variability, including explosive eruptions, passive volcanic degassing, and anthropogenic emissions. We evaluate the dataset against SO2 plume-height estimates from the Infrared Atmospheric Sounding Interferometer (IASI). Despite differences in vertical sensitivity and overpass time, the datasets generally agree well, with biases mainly within 0.7–4 km depending on observation conditions and plume properties. Comparisons with SO2 height estimates from the trajectory-based PlumeTraj toolkit show excellent consistency, with biases below 1 km in most cases. The results highlight the complementarity of the three datasets and the potential benefit of combining them to obtain reliable information on SO2 plume height across the whole atmosphere. The TROPOMI product provides a useful resource for monitoring and quantifying volcanic SO2 emissions and assessing their environmental impacts.
Competing interests: At least one of the (co-)authors is a member of the editorial board of Atmospheric Chemistry and Physics.
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