Airborne Observations of BrO and HOBr by Chemical Ionization Mass Spectrometry (CIMS) during CONTRAST (CONvective TRansport of Active Species in the Tropics)
Tuesday, 16 December 2014
Inorganic bromine species such as BrO play important roles in the photochemistry of both the troposphere and stratosphere. A primary goal of the CONTRAST campaign was to determine the budget of inorganic bromine in the tropical tropopause. In order to address this issue BrO and HOBr were measured by CIMS on a series of research flights out of Guam. Here we will present our initial observations and compare them to both photochemical and chemical transport models. Preliminary results indicate very low levels of BrO (generally <0.5ppt) in the upper troposphere unless significant mixing ratios of ozone (>70ppbv) were present. The origin(s) of elevated BrO (>1pptv) will be discussed and comparison of CIMS measurements to preliminary DOAS (Differential Optical Absorption Spectroscopy) data will also be presented.