13th International Atmospheric Limb Workshop

Arch effects and retrieval artifacts below the Hunga Tonga plume: Estimating the uncertainties in the OMPS aerosol extinction coefficient using CALIOP data

Not scheduled

20m

Gartensaal (Schloss Karlsruhe)

Poster

Speaker

Christine Pohl (Institute of Environmental Studies, University of Bremen, Germany)

Description

Due to its high spatio-temporal sampling coverage, the aerosol extinction coefficient (Ext) obtained from OMPS Limb scattering observations is excellently suited for observing the temporal aerosol evolution in the stratosphere after strong volcanic eruptions and wildfires. The record of Ext has been recently improved by the University of Bremen (UB), successfully validated with SAGE III/ISS observations (Rozanov et al., 2024) and is currently beeing compared with other existing OMPS Ext products. The UB retrieval algorithm shows a good performance. Especially the vertical extent of the stratospheric aerosol plume is well represented by the UB OMPS Ext product. However, the Ext values below strong aerosol plumes can be subject to higher uncertainties due to the arch effect and retrieval instabilities. Both effects can occur regularly when strong aerosol plumes are observed in the limb-viewing geometry. While arch effects cause an increase in Ext, retrieval instabilities can cause both too high and much too low Ext values. We estimate these uncertainties by comparing Level 2 OMPS Ext and CALIOP data after the 2022 Hunga eruption.