Bromine in the tropical troposphere and stratosphere as derived from balloon-borne BrO observations

• Main Authors: M. Dorf, A. Butz, C. Camy-Peyret, M. P. Chipperfield, L. Kritten, K. Pfeilsticker
• Format: Article
• Language: English
• Published: Copernicus Publications 2008-12-01
• Series: Atmospheric Chemistry and Physics
• Online Access: http://www.atmos-chem-phys.net/8/7265/2008/acp-8-7265-2008.pdf

The first tropospheric and stratospheric (4 to 33 km) BrO profile is presented for the inner tropics derived from balloon-borne DOAS (Differential Optical Absorption Spectroscopy) measurements. In combination with photochemical modelling, total stratospheric inorganic bromine (Br<sub>y</sub>) is deduced to be (21.5±2.5) ppt in 4.5-year-old air, probed in 2005. We derive a total contribution of (5.2±2.5) ppt from brominated very short-lived substances and inorganic product gases to stratospheric Br<sub>y</sub> Tropospheric BrO was found to be <1 ppt. Our results are compared to two 3-D CTM SLIMCAT model runs, which differ in the lifetime of the bromine source gases, affecting the vertical distribution of Br<sub>y</sub> in the lower stratosphere. Bromine source gas measurements performed 10 days earlier Laube et al., 2008, indicate a lower Br<sub>y</sub> of (17.5±0.4) ppt. Potential reasons for this discrepancy are discussed.