Hannover 2010 – wissenschaftliches Programm
UP 2.20: Poster
Dienstag, 9. März 2010, 16:30–18:30, Lichthof
Simultaneous observations of IO and BrO over the Antarctic from space — •Anja Schönhardt1, Andreas Richter1, Mathias Begoin1, Folkard Wittrock1, and John P. Burrows1,2 — 1Institut für Umweltphysik, Universität Bremen, Deutschland — 2Centre for Ecology and Hydrology, Wallingford, United Kingdom
Reactive halogen species (RHS, i.e., iodine, bromine, chlorine, and their oxides) are important for atmospheric composition, e.g., through ozone depletion, mercury oxidation (by bromine monoxide, BrO) or new particle formation (initiated by iodine oxides). Research on RHS has therefore intensified, as open questions still remain, e.g., on the atmospheric sources of RHS and differences between individual halogen species.
Recently, it has become possible to measure iodine monoxide (IO) columns using the SCIAMACHY satellite instrument. IO has been detected over the Antarctic around and on the continent, the ice shelves and the sea ice. In the present study, simultaneous satellite measurements of IO and BrO distributions are compared, utilizing multi-year averages of short time periods. Although both species occur partly in the same region and time, differences are identified in the detailed spatial and temporal patterns. While BrO mainly appears on the sea ice with a maximum from early spring until summer, IO reveals a more detailed evolution, e.g., with high amounts close to the continent in early spring and rising amounts over sea ice regions only towards late spring and summer. The observations provide arguments for different release pathways of the two halogen compounds and evidence increases that iodine is mainly released from the biosphere.