Dresden 2011 – scientific programme

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UP: Fachverband Umweltphysik

UP 1: Poster Session

UP 1.12: Poster

Tuesday, March 15, 2011, 18:30–20:30, P2

Vertical columns of IO from satellite observations: sensi-tivity studies and latest results — •Anja Schönhardt, Andreas Richter, Mathias Begoin, Folkard Wittrock, and John P. Burrows — Institute of Environmental Physics, Bremen, Germany

Halogen oxides strongly influence tropospheric composition, they are closely linked to the depletion of ozone, they alter oxidation pathways, and iodine oxides may initiate new particle formation in the boundary layer. About ten years ago, atmospheric iodine monoxide (IO) was measured from ground-based instruments for the first time. Lately, IO is also observed from satellite, i.e. from the SCIAMACHY instrument on ENVISAT. Remote sensing of minor trace gases such as IO is a challenge as the retrieval is fairly sensitive to certain settings in the algorithm. IO has been positively detected in some locations and time periods, e.g., in Antarctic spring time. The spatial and temporal distributions of IO, also in comparison to those of bromine oxide, may be in part understood and in part raise new questions.

This contribution presents latest results from satellite IO observations as well as selected sensitivity studies. These studies address the sensitivity of the retrieved IO slant column to initial retrieval settings as well as the sensitivity of the air mass factor to assumptions in the radiative transfer calculations. Sensitivity studies are necessary for determining retrieval settings which deliver the most consistent results, and in addition for identifying potential errors and misleading results. Consistency within the entire retrieval and comparisons to additional products, measurements and individual studies are required.