Observations of iodine monoxide columns from satellite A. Schönhardt1, A. Richter1, F. Wittrock1, H. Kirk1, H. Oetjen1,*, H. K. Roscoe2, and J. P. Burrows1 1Institute of Environmental Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany 2British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK *now at: School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK
Abstract. Iodine species in the troposphere are linked to ozone depletion and new
particle formation. In this study, a full year of iodine monoxide (IO)
columns retrieved from measurements of the SCIAMACHY satellite instrument is
presented, coupled with a discussion of their uncertainties and the detection
limits. The largest amounts of IO are found near springtime in the Antarctic.
A seasonal variation of iodine monoxide in Antarctica is revealed with high
values in springtime, slightly less IO in the summer period and again larger
amounts in autumn. In winter, no elevated IO levels are found in the areas
accessible to satellite measurements. This seasonal cycle is in good
agreement with recent ground-based measurements in Antarctica. In the Arctic
region, no elevated IO levels were found in the period analysed. This implies
that different conditions with respect to iodine release exist in the two
Polar Regions. To investigate possible release mechanisms, comparisons of IO
columns with those of tropospheric BrO, and ice coverage are described and
discussed. Some parallels and interesting differences between IO and BrO
temporal and spatial distributions are identified. Overall, the large spatial
coverage of satellite retrieved IO data and the availability of a long-term
dataset provide new insight about the abundances and distributions of iodine
compounds in the troposphere.
Citation: Schönhardt, A., Richter, A., Wittrock, F., Kirk, H., Oetjen, H., Roscoe, H. K., and Burrows, J. P.: Observations of iodine monoxide columns from satellite, Atmos. Chem. Phys., 8, 637-653, doi:10.5194/acp-8-637-2008, 2008.