The paper provides a thorough record of volcanic SO2 column abundances and plume altitudes from 2007 to 2025, utilizing data from the three IASI instruments aboard Metop platforms. The first section details enhancements to SO2 retrieval methods, including sensitivity and uncertainty analyses. Notably, the refined retrievals demonstrate increased sensitivity to low SO2 concentrations at plume edges and improved plume altitude estimates for large columns. The authors have ensured consistency across instruments and throughout the time series. Uncertainty is minimized for SO2 plumes above 8 km, but increases at lower altitudes, especially in conditions of elevated atmospheric water vapor, and clouds and ash presence. Comparisons with CALIOP and TROPOMI reveal that plume altitude retrievals are accurate within 1–2 km, except for the case of high stratospheric Hunga plum, where explicit height constraint was necessary (figure 8). Overall, there is reasonable agreement with TROPOMI SO2 column retrievals for volcanic plumes above 8 km. The latter part of the manuscript introduces the 18-year IASI dataset, emphasizing volcanic SO2 mass, altitude distribution, and comparisons with prior IR and UV SO2 mass retrievals. The presentation is clear, and the manuscript is ready for publication.

Krotkov, et al., Day-Night Monitoring of Volcanic SO2 and Ash Clouds for Aviation Avoidance at Northern Polar Latitudes, Remote Sensing, 2021, https://doi.org/10.3390/rs13194003 , 2021

Li, C., et al., Version 1 NOAA-20/OMPS Nadir Mapper total column SO₂ product: continuation of NASA long-term global data record, Earth Syst. Sci. Data, 16, 4291–4309, https://doi.org/10.5194/essd-16-4291-2024

Li, Can, et al., Version 2 Ozone Monitoring Instrument SO2 Product (OMSO2 V2): New Anthropogenic SO2 Vertical Column Density Dataset, Atmos. Meas. Tech., 13, 6175–6191, 2020 https://doi.org/10.5194/amt-13-6175-2020

The paper is well written. authors have demonstrated a new algorithm to retieve atmospheric SO2 plume altitudes from Global measurements. Further compared with available observations datasets for different case studies. Although challenges from cloud and ash remains in the study, which is understandable and remain for future study. Authors provided a good dataset for further research. With the present knowledge data set is significant, high quality and useful.