Bromine Chemistry in the Tropical UTLS during the 2011, 2013 and 2014 ATTREX Experiments

Thursday, 18 December 2014: 2:55 PM
Jochen Stutz1, Max Spolaor1, James Festa1, Jui Yi Tsai1, Santo F Colosimo1, Ross Cheung1, Bodo Werner2, Tim Deutschmann2, Lisa Scalone2, Rasmus Raecke3, Ugo Tricoli2, Klaus Pfeilsticker2, Maria A Navarro4 and Elliot L Atlas4, (1)University of California Los Angeles, Los Angeles, CA, United States, (2)University of Heidelberg, Institut fuer Umweltphysik, Heidelberg, Germany, (3)Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research (IMK-ASF), Karlsruhe, Germany, (4)University of Miami, Miami, FL, United States
Bromine chemistry impacts the levels of ozone in the upper troposphere and the stratosphere. An accurate quantitative understanding of the sources, sinks, and chemical transformation of bromine species is thus important to understand the bromine budget in the upper troposphere and lower stratosphere (UTLS), which also serves as a gate to the stratosphere. Vertical transport of very short-lived organic bromine precursors, such as CHBr3, CH2Br2 and inorganic product gases has been identified as the main source of bromine in the UTLS. However, the contribution of inorganic vs. organic compounds is not well quantified, particularly in the tropical UTLS. A number of chemical processes, including the role of ice particles for the transformation and cycling of inorganic bromine species are also poorly understood.

A limb scanning Differential Optical Absorption Spectroscopy Instrument was deployed on-board NASA’s unmanned high-altitude Global Hawk aircraft during the 2011, 2013, and 2014 NASA Airborne Tropical TRopopause EXperiment (ATTREX). Flights in the eastern and western Pacific were performed to study, among other topics, the chemistry of bromine and ozone in the subtropical and tropical UTLS. Here we will present observations of BrO, NO2 and other trace species made by this instrument at altitudes between 15 – 20 km. The measurement methodology as well as the procedure to retrieve vertical trace gas concentration profiles will be briefly presented. The combination of those observations with the measurements of organic bromine species from the University of Miami’s Whole Air Sampler (GWAS) will be used to determine and interpret the bromine budget in the UTLS.