Atmospheric Chemistry and Physics (Dec 2017)
BrO and inferred Br<sub><i>y</i></sub> profiles over the western Pacific: relevance of inorganic bromine sources and a Br<sub><i>y</i></sub> minimum in the aged tropical tropopause layer
- T. K. Koenig,
- T. K. Koenig,
- R. Volkamer,
- R. Volkamer,
- S. Baidar,
- S. Baidar,
- S. Baidar,
- B. Dix,
- S. Wang,
- S. Wang,
- S. Wang,
- D. C. Anderson,
- D. C. Anderson,
- R. J. Salawitch,
- R. J. Salawitch,
- R. J. Salawitch,
- P. A. Wales,
- C. A. Cuevas,
- R. P. Fernandez,
- R. P. Fernandez,
- A. Saiz-Lopez,
- M. J. Evans,
- T. Sherwen,
- D. J. Jacob,
- D. J. Jacob,
- J. Schmidt,
- D. Kinnison,
- J.-F. Lamarque,
- E. C. Apel,
- J. C. Bresch,
- T. Campos,
- F. M. Flocke,
- S. R. Hall,
- S. B. Honomichl,
- R. Hornbrook,
- J. B. Jensen,
- R. Lueb,
- D. D. Montzka,
- L. L. Pan,
- J. M. Reeves,
- S. M. Schauffler,
- K. Ullmann,
- A. J. Weinheimer,
- E. L. Atlas,
- V. Donets,
- M. A. Navarro,
- D. Riemer,
- N. J. Blake,
- D. Chen,
- D. Chen,
- L. G. Huey,
- D. J. Tanner,
- T. F. Hanisco,
- G. M. Wolfe,
- G. M. Wolfe
Affiliations
- T. K. Koenig
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO, USA
- T. K. Koenig
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- R. Volkamer
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO, USA
- R. Volkamer
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- S. Baidar
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO, USA
- S. Baidar
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- S. Baidar
- now at: Chemical Sciences Division, National Oceanic and Atmospheric Administration (NOAA), Boulder, CO, USA
- B. Dix
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, CO, USA
- S. Wang
- Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO, USA
- S. Wang
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
- S. Wang
- now at: National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- D. C. Anderson
- Department of Atmospheric & Oceanic Science, University of Maryland, College Park, MD, USA
- D. C. Anderson
- now at: Department of Chemistry, University of Drexel, Philadelphia, PA, USA
- R. J. Salawitch
- Department of Atmospheric & Oceanic Science, University of Maryland, College Park, MD, USA
- R. J. Salawitch
- Department of Chemistry & Biochemistry, University of Maryland, College Park, MD, USA
- R. J. Salawitch
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
- P. A. Wales
- Department of Chemistry & Biochemistry, University of Maryland, College Park, MD, USA
- C. A. Cuevas
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, Spanish National Research Council (CSIC), Madrid, Spain
- R. P. Fernandez
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, Spanish National Research Council (CSIC), Madrid, Spain
- R. P. Fernandez
- Argentine National Research Council (CONICET), FCEN-UNCuyo, UNT-FRM, Mendoza, Argentina
- A. Saiz-Lopez
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, Spanish National Research Council (CSIC), Madrid, Spain
- M. J. Evans
- Wolfson Atmospheric Chemistry Laboratories (WACL), Department of Chemistry, University of York, York, UK
- T. Sherwen
- Wolfson Atmospheric Chemistry Laboratories (WACL), Department of Chemistry, University of York, York, UK
- D. J. Jacob
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- D. J. Jacob
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
- J. Schmidt
- Department of Chemistry, Copenhagen University, Copenhagen, Denmark
- D. Kinnison
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- J.-F. Lamarque
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- E. C. Apel
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- J. C. Bresch
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- T. Campos
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- F. M. Flocke
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- S. R. Hall
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- S. B. Honomichl
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- R. Hornbrook
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- J. B. Jensen
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- R. Lueb
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- D. D. Montzka
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- L. L. Pan
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- J. M. Reeves
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- S. M. Schauffler
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- K. Ullmann
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- A. J. Weinheimer
- National Center for Atmospheric Research (NCAR), Boulder, CO, USA
- E. L. Atlas
- Department of Atmospheric Science, Rosenstiel School of Marine & Atmospheric Sciences (RSMAS), University of Miami, Miami, FL, USA
- V. Donets
- Department of Atmospheric Science, Rosenstiel School of Marine & Atmospheric Sciences (RSMAS), University of Miami, Miami, FL, USA
- M. A. Navarro
- Department of Atmospheric Science, Rosenstiel School of Marine & Atmospheric Sciences (RSMAS), University of Miami, Miami, FL, USA
- D. Riemer
- Department of Atmospheric Science, Rosenstiel School of Marine & Atmospheric Sciences (RSMAS), University of Miami, Miami, FL, USA
- N. J. Blake
- Department of Chemistry, University of California, Irvine, CA, USA
- D. Chen
- School of Earth & Atmospheric Sciences, Georgia Tech, Atlanta, Georgia, USA
- D. Chen
- now at: Department of Chemical Engineering, Carnegie Mellon University (CMU), Pittsburgh, PA, USA
- L. G. Huey
- School of Earth & Atmospheric Sciences, Georgia Tech, Atlanta, Georgia, USA
- D. J. Tanner
- School of Earth & Atmospheric Sciences, Georgia Tech, Atlanta, Georgia, USA
- T. F. Hanisco
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- G. M. Wolfe
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- G. M. Wolfe
- Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, MD, USA
- DOI
- https://doi.org/10.5194/acp-17-15245-2017
- Journal volume & issue
-
Vol. 17
pp. 15245 – 15270
Abstract
We report measurements of bromine monoxide (BrO) and use an observationally constrained chemical box model to infer total gas-phase inorganic bromine (Bry) over the tropical western Pacific Ocean (tWPO) during the CONTRAST field campaign (January–February 2014). The observed BrO and inferred Bry profiles peak in the marine boundary layer (MBL), suggesting the need for a bromine source from sea-salt aerosol (SSA), in addition to organic bromine (CBry). Both profiles are found to be C-shaped with local maxima in the upper free troposphere (FT). The median tropospheric BrO vertical column density (VCD) was measured as 1.6×1013 molec cm−2, compared to model predictions of 0.9×1013 molec cm−2 in GEOS-Chem (CBry but no SSA source), 0.4×1013 molec cm−2 in CAM-Chem (CBry and SSA), and 2.1×1013 molec cm−2 in GEOS-Chem (CBry and SSA). Neither global model fully captures the C-shape of the Bry profile. A local Bry maximum of 3.6 ppt (2.9–4.4 ppt; 95 % confidence interval, CI) is inferred between 9.5 and 13.5 km in air masses influenced by recent convective outflow. Unlike BrO, which increases from the convective tropical tropopause layer (TTL) to the aged TTL, gas-phase Bry decreases from the convective TTL to the aged TTL. Analysis of gas-phase Bry against multiple tracers (CFC-11, H2O ∕ O3 ratio, and potential temperature) reveals a Bry minimum of 2.7 ppt (2.3–3.1 ppt; 95 % CI) in the aged TTL, which agrees closely with a stratospheric injection of 2.6 ± 0.6 ppt of inorganic Bry (estimated from CFC-11 correlations), and is remarkably insensitive to assumptions about heterogeneous chemistry. Bry increases to 6.3 ppt (5.6–7.0 ppt; 95 % CI) in the stratospheric "middleworld" and 6.9 ppt (6.5–7.3 ppt; 95 % CI) in the stratospheric "overworld". The local Bry minimum in the aged TTL is qualitatively (but not quantitatively) captured by CAM-Chem, and suggests a more complex partitioning of gas-phase and aerosol Bry species than previously recognized. Our data provide corroborating evidence that inorganic bromine sources (e.g., SSA-derived gas-phase Bry) are needed to explain the gas-phase Bry budget in the upper free troposphere and TTL. They are also consistent with observations of significant bromide in Upper Troposphere–Lower Stratosphere aerosols. The total Bry budget in the TTL is currently not closed, because of the lack of concurrent quantitative measurements of gas-phase Bry species (i.e., BrO, HOBr, HBr, etc.) and aerosol bromide. Such simultaneous measurements are needed to (1) quantify SSA-derived Bry in the upper FT, (2) test Bry partitioning, and possibly explain the gas-phase Bry minimum in the aged TTL, (3) constrain heterogeneous reaction rates of bromine, and (4) account for all of the sources of Bry to the lower stratosphere.
