Currently, to predict the concentration of sulfur dioxide of volcanic origin in the French chemistry-model MOCAGE, SO2 total columns providing from TROPOMI and IASI satellites are assimilated in MOCAGE. Nevertheless, we assume that the SO2 plume is between 3 and 10km of altitude, which is not the case for all volcanic eruptions. A way to improve our analyses and the forecasts is to use information about the height of the plume.

TROPOMI on Sentinel-5p is able to measure SO2 columns with high horizontal resolution from the surface to the top of the atmosphere with an information altitude of the plume for the strong total columns. The IASI instruments on Metop B and C measure total SO2 columns with a lower resolution than TROPOMI and do not give any information on the presence of volcanic SO2 below 5km altitude, but they give an information about height even for weak SO2 total columns. Height is used to constrain the altitude of plume and the thickness in the model. This presentation will give a comparison between the assimilation with and without height information on different eruptive events.