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UP: Fachverband Umweltphysik

UP 12: Satellitengestützte Messungen

UP 12.2: Vortrag

Donnerstag, 13. März 2008, 12:00–12:15, 3B

Seasonal variations of IO above Antarctica observed in three years of satellite data — •Anja Schönhardt¹, Andreas Richter¹, Folkard Wittrock¹, Henning Kirk¹, Hilke Oetjen², and John P. Burrows¹ — ¹Institut für Umweltphysik, Bremen, Germany — ²School of Chemistry, University of Leeds, UK

Halogen oxides play an important role in the Earth's atmosphere. Iodine species lead to destruction of tropospheric ozone, a reaction in which iodine monoxide (IO) is produced, and enhanced abundances of IO can result in the formation of fine particles. To gain more knowledge and understanding of its global importance, it is interesting to measure IO not only locally from the ground but also from satellite on a global scale. IO has strong differential absorption structures in the visible wavelength range making it a suitable trace gas for DOAS (Differential Optical Absorption Spectroscopy) measurements.

Nadir observations from the SCIAMACHY satellite instrument are analysed for a period of three full years. Apart from a discussion of the IO detection limit, our study concentrates on the retrieval of IO close to Antarctica. While enhanced amounts of IO and a seasonal variation can be seen there, no clear signal of enhanced IO is found in the Northern Hemisphere. In each of the three years under investigation, the seasonal variation above Antarctica is repeated in the same form with highest values in polar spring, slightly decreasing values during summertime and again rising amounts towards autumn. In winter, no clearly enhanced values are detected. These findings alongside with first suggestions for the interpretation are presented.