Sulphur Dioxide - SO2 layer height

The validation of the S5P TROPOMI L2_SO2 sulphur dioxide plume height is based on satellite-to satellite comparisons, during large enough volcanic eruptions, with the Metop-B/C IASI “SO2_vertical_level” product, i.e., the retrieved vertical level of the SO2 plume, for the morning (AM) observations. Overall, TROPOMI shows lower SO2 layer height retrievals compared to the combined IASI/Metop[B&C] SO2 plume height observations by ~42 %, for both 2023-present (original validation) and 2018-present (RPRO) periods, equivalent to a mean SO2 layer height difference of ~3.2 km and ~3.5 km, respectively. HYSPLIT airmass forward/backward trajectories can be employed as a validation tool of the S5P TROPOMI SO₂_Layer_Height observations and results usually indicate a good agreement between the height of trajectories and the height and location of the SO₂ plume.