Analysing satellite data for IO vertical columns in polar and tropical regions

Striking differences between the distributions of iodine and bromine oxide as well as interrelations between IO and sea ice as well as between IO and biological activity (e.g., chlorophyll-a concentrations) further contribute to the discussion of the tropospheric role of iodine. The present study focuses on the latest results of IO observations from satellite, covering up to eight years of SCIAMACHY data. By applying reasonable assumptions for the radiative transfer, IO vertical columns are calculated. Influences and uncertainties in this processing step are discussed. The regions of main focus are the Antarctic and the tropical oceans. In addition, sensitivity studies of the final IO vertical columns are presented. Due to the smallness of the IO signal, precaution needs to accompany the entire analysis in order to prevent misleading scientific results. This is demonstrated by suitable examples.