BrO in the Tropical and Subtropical UTLS: Longitudinal Gradients over the Pacific Ocean

Tuesday, 16 December 2014
Barbara K Dix1, Rainer M Volkamer2, Sunil Baidar3, Theodore Konstantinos Koenig4, Sean Coburn5, Ivan Ortega6, Dexian Chen7, Greg Huey8, David Tanner9, Tomas Sherwen10, Mathew J Evans10, Eric C Apel11, Rebecca S Hornbrook12, Nicola J Blake13, Alan J Hills12, Douglas Edward Kinnison12, J F Lamarque11, Alfonso Saiz-Lopez14, R. Bradley Pierce15, Johan Schmidt16,17, Daniel J. Jacob17, Elliot L Atlas18, Laura Pan11 and Ross J Salawitch19, (1)University of Colorado at Boulder, Boulder, CO, United States, (2)Univ. of Colorado, Boulder, Boulder, CO, United States, (3)University of Colorado at Boulder, Cooperate Institute for Research in Environmental Sciences, Boulder, CO, United States, (4)University of Colorado at Boulder, Department of Chemistry and Biochemistry, Boulder, CO, United States, (5)University of Colorado, Boulder, CO, United States, (6)Univ of Colorado, Boulder, CO, United States, (7)Georgia Institute of Technology Main Campus, Atlanta, GA, United States, (8)Georgia Institute of Technology Main Campus, School of Earth and Atmospheric Sciences, Atlanta, GA, United States, (9)Georgia Tech, Atlanta, GA, United States, (10)University of York, York, United Kingdom, (11)National Center for Atmospheric Research, Boulder, CO, United States, (12)NCAR, Boulder, CO, United States, (13)University of California Irvine, Irvine, CA, United States, (14)Spanish National Research Council, Zaragoza, Spain, (15)NOAA/NESDIS, Center for Satellite Application and Research, Madison, WI, United States, (16)Harvard University, Cambridge, MA, United States, (17)Harvard University, School of Engineering and Applied Sciences, Cambridge, MA, United States, (18)University Miami, Miami, FL, United States, (19)University of Maryland, College Park, MD, United States
Bromine oxide (BrO) is a halogen radical that catalytically destroys ozone, modifies the oxidative capacity of the atmosphere and oxidizes atmospheric mercury. About 75% of the global tropospheric ozone loss occurs at tropical latitudes, where the ozone radiative forcing is most sensitive to changes in the ozone concentration. Here we report on BrO observations in the tropical and sub-tropical free troposphere and UTLS. Airborne measurements of BrO vertical profiles were performed by the University of Colorado Airborne Multi Axis DOAS (CU AMAX-DOAS) instrument aboard the NSF/NCAR GV aircraft. We compare BrO profiles measured at tropical and subtropical latitudes over the Western Pacific (CONvective TRansport of Active Species in the Tropics, CONTRAST, field campaign) with tropical BrO profiles measured over the Central (Mauna Loa Observatory fly-by) and Eastern Pacific ocean (Tropical Ocean tRoposphere Exchange of Reactive halogen species and Oxygenated VOC, TORERO, experiment). For selected case studies we compare BrO profiles from three independent instruments, i.e., CU AMAX-DOAS, mountain-top MAX-DOAS at Mauna Loa Observatory, and Chemical Ionization Mass Spectrometry and BrO predictions from global models (CAM-Chem, GEOS-Chem and RAQMS).