1)Division of Marine and Atmospheric Chemistry, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida, USA 2)Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado, USA 3)Atmospheric Chemistry and Climate Group, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain Geographical Distribution of Brominated Organic Trace Gases in the UT/LS region of the Pacific Maria Navarro 1, E. Atlas 1, A. Saiz-Lopez 3, X. Rodriguez-Lloveras 3, R. Lueb 1, R. Hendershot 2, S. Gabbard 2, D. Kinnison 2, JF. Lamarque 2, S.Tilmes 2, C. Cuevas 3, S. Schauffler 2, V. Donets 1, X. Zhu 1, L. Pope 1 1

OBJECTIVES I- Characterize variability and distribution of organic bromine species in the UT/LS of the Eastern and Western Pacific. II- Determine the amount of total very short lived brominated species (VSL Br = VSL org + Br y ) that enters the stratosphere. Examine the amount of inorganic bromine present at the Tropical Tropopause and the partitioning of these species from modeling results. III- Examine the inter-hemispheric distribution of VSL org.

MOTIVATION One of ATTREX questions: “What is the vertical distribution of BrO and short lived halogen compounds in the TTL and how does it vary seasonally and geographically?” Uncertainties on the amount of VSL Br reaching the stratosphere (2-8 ppt according to WMO-2014) 3

ATTREX locations and area of study Longitude Latitude 541 samples 68 vertical profiles 388 samples 45 vertical profiles ATTREX-3 (2014) WESTERN PACIFIC ATTREX-2 (2013) EASTERN PACIFIC Global Hawk Whole Air Sampler (GWAS)

Trace Gas Species from GWAS 5 Halons Halon 1211 Halon 2402 Halon 1301 Chlorofluorocarbons CFC A CFC A CFC A Hydrochlorofluoroarbons/ Hydrofluorocarbons HCFC_141b 9.4 A HCFC A HCFC_142b 19.5 A Solvent Carbon Tetrachloride 40 A Methyl chloroform 4.8 A Other Carbonyl Sulfide (COS) 30 N/A/B Methyl Chloride 1.5 N/B Methyl Halides Bromoform Methyl Bromide Methylene Bromide Methyl Iodide CHxBryClz Solvents Yrs S Methylene Chloride 0.3 A Chloroform 0.4 A/N Tetrachloroethylene 0.3 A Trichloroethylene 0.02 A Organic nitrates Methyl nitrate 0.08 A/N Ethyl nitrate 0.04 A/N Propyl nitrate 0.03 A/N Non- Methane Halocarbons Ethane (C2H6) 0.2 A Ethyne 0.06 A/B Propane 0.04 A Benzene 0.04 A/B Others 1,2 dichloro ethane 0.3 A Chlorobenzene 0.05 A Longer Lived Species Shorter Lived Species Sources A= antropogenic/industrial N= natural/marine B=Biomass burning CBrClF 2 C 2 Br 2 F 4 CBrF N 0.8 A/N/B 0.4 N 0.01 N 0.1 N Yrs S 20 A CHBr 3 CH 3 Br CH 2 Br 2 Yrs S Shorter Lived Species Minor VSLBr Bromodichloromethane CHBrCl 2 Dibromochloromethane CHBr 2 Cl Bromochloromethane CH 2 BrCl

CAM-Chem Community Atmosphere Model (CAM V.5) (details in: Lamarque et al., Geosci. Mod. Dev., 2012, Ordoñez et al., ACP, 2012 and Saiz-Lopez et al., ACP, 2012) Simulations with specific meteorological fields Vertical resolution: 56 levels (surface to ~ 993 hPa) Spatial resolution 1° x 1° Temporal resolution: 30 min Tropospheric Halogen Chemistry Chemical Processes Halogen gas phase photochemistry (Cl, Br, and I) Dry / wet deposition Heterogeneous chemistry on sea-salt aerosols and ice particles 9 additional VSL halocarbon species included. Halogenated VSL sources from the ocean Emissions following Chl-a over tropics (SeaWIFS) Geographical and temporal distribution of VSL sources 6

Sampling Density of Organic Br Species # Samples Alt (Km) WESTERN 7 CH 2 BrCl CH 2 Br 2 CHBrCl 2 CHBr 2 Cl CHBr 3 CH 3 Br Halon 1211 Halon 2402

I- Variability and Distribution of GWAS Organic Bromine Species 8

Variability and Distribution of GWAS Organic Bromine Species WESTERN PACIFICEASTERN PACIFIC Mixing ratios (pmol/mol) Alt (mts) Bin 1Km Alt Error =1sd 0.03%1.3% 60% 49% Halon 2402 Halon 1211 CH 3 Br 0.05% 1.96 % 1.3% 0.7 % 22% 17% CHBr 3 CH 2 Br 2 Minor VSLBr Minor VSL =CH 2 BrCl+CHBr 2 Cl +CHBrCl 2

CAM-Chem: Variability and Distribution of Organic Bromine Species WESTERN PACIFIC EASTERN PACIFIC Halon 2402 Halon 1211 CH 3 Br Minor VSLBr CHBr 3 CH 2 Br 2 Alt (Km) Mixing ratios (pmol/mol) Bin 1Km Alt Error model and measurements =1sd

11 Organic Bromine Species by Groups WESTERN PACIFICEASTERN PACIFIC TOTAL HALONS = HALON HALON HALON 1301 CH 3 Br = CH 3 Br VERY SHORT LIVED Br (VSL org ) = CHBr 3 + CH 2 Br 2 + CHBrCl 2 + CHBr 2 Cl + CH 2 BrCl pmol/mol ALT (km) VSl org CH 3 Br Total Halons Bin 1Km Alt Error model and measurements =1sd

II- VSL org and Br y at the Tropical Tropopause 12

Organic Bromine Budget at the Tropopause (17Km) TOTAL HALONS = HALON (2*HALON 2402)+ HALON 1301 CH3Br = CH 3 Br VERY SHORT LIVED Br (VSL org ) = (3* CHBr 3 )+ (2* CH 2 Br 2 ) + CHBrCl 2 + (2*CHBr 2 Cl)+ CH 2 BrCl VERY SHORT LIVED Br (VSL org ) = (3* CHBr 3 )+ (2* CH 2 Br 2 ) + Minor 17KmWestern (pmol Br/mol)Eastern (pmol Br/mol) Halons7.59 ± ± 0.11 CH 3 Br7.16 ± ± 0.23 VSL org 3.27 ± ± 0.42 Total Org Br Budget ± ± 0.49 ORGANIC BROMINE BUDGET

Br org budget =18.02± 0.66 pmol Br/mol Br org budget =17.68± 0.49 pmol Br/mol WESTERN PACIFICEASTERN PACIFIC VSL 17KmSTRAT 1996 (1) (%) Halons38 CH 3 Br55 VSL org 6.8 Total Org Br Budget (ppt) 17.4 ± 17KmCRA-VE 2006 (%) Halons47 CH 3 Br45 VSL org 8 Total Org Br Budget (ppt) 17.5 ± 0.6 (1) Schauffier et al., GRL vol 25 # 3, 1998 VSl org CH 3 Br Total Halons Organic Bromine Budget at the Tropopause (17Km)

VSL 17KmWESTERN PACIFICEASTERN PACIFIC GWAS measurements3.27 ± ± 0.42 WESTERN PACIFICEASTERN PACIFIC VSL 17KmWESTERN PACIFICEASTERN PACIFIC GWAS measurements3.27 ± ± 0.42 CAM-Chem3.84 ± ± 1.49 VSL org in the Pacific Tropical Tropopause Pmol Br/mol Alt (Km) 15 Minor VSLBr CHBr 3 CH 2 Br 2 VSL org

WESTERN PACIFIC EASTERN PACIFIC Br 17KmWESTERN PACIFICEASTERN PACIFIC CAM-Chem1.97 ± ± 1.90 Inorganic Bromine in the Pacific Tropical Tropopause Pmol Br/mol Alt (Km) 16 Minor VSLBr CHBr 3 CH 2 Br 2 VSL org Br y = Br+BrO+HOBr+BONO 2 +HBr+BrCl+2Br 2 +BrNO 2 +IBr Br y

VSL 17KmWESTERN PACIFIC (ppt) EASTERN PACIFIC (ppt) GWAS measurements3.27 ± ± 0.42 CAM-Chem3.84 ± ± 1.49 Br 17KmWESTERN PACIFIC (ppt) EASTERN PACIFIC (ppt) CAM-Chem1.97 ± ± 1.90 VSL org VSL org and Inorganic Bromine in the Tropopause 17

WESTERN PACIFIC EASTERN PACIFIC Bromine Fraction in the Pacific Tropical Tropopause Why do we have: Different Br y mixing ratios Similar VSL org mixing ratios 18 Abundance of Br y is ½ of the abundance of VSL org in Western Pacific Abundance of Br y is similar to abundance of VSL org in Eastern Pacific Since VSL org mixing ratio is similar in both region, Br y mixing ratio in the Eastern Pacific is twice than in the Western Pacific

VSL org Emission fluxes WESTERN PACIFIC EASTERN PACIFIC Total VSL org EmissionWESTERN PACIFIC ( 10e +07 molecule/cm 2 /sec) EASTERN PACIFIC ( 10e +07 molecule/cm 2 /sec) CAM-Chem In less convective area (LIKE THE EASTERN PACIFIC) VSL org have time to react  more Br y production Higher VSL org emission  compensate the loss due to rxn CH 2 Br 2 CH 3 Br Minor VSL 10e +07 molecule/cm 2 /sec

WESTERN PACIFIC EASTERN PACIFIC VSLBr = VSL org + Br y 5.81 ± 0.67 ppt 6.20 ± 2.41 ppt VSLBr (ppt)WESTERNEASTERN ATTREX 5.81 ( )6.20 ( ) 20 Injection of Total VSL Brominated Species (VSL Br = VSL org + Br y ) WMO (2014)~ 5 (2-8) ATTREX ESTIMATED~ 6 (4-9) NARROW RANGE

21 Inorganic Bromine Partitioning in the Pacific Tropical Tropopause 21

Sampling density and geographical distribution day and night Western PacificEastern Pacific day14681 night28210 No twilight samples (80 <TAS <100) °E 170°E 170°W 150°W 130°W 110°W 20°S 0° 20°N 40°N Day twilight Night Solar Zenith Angle Number of samples Western Eastern

23 Br y partitioning in the Pacific Tropical Tropopause WESTERN PACIFICEASTERN PACIFIC DAY NIGHT Mixing ratio (ppt) 17Km 50.1 % 17Km 47.8 % BrONO 17Km 50.1 % 17Km 57.7 % Br BrNO 2 +Br 2 HBrBrONO 2 HOBr BrO BrCl IBr Alt (Km)

Modeled O 3 -NO 2 and Cl y mixing ratios WESTERN PACIFICEASTERN PACIFIC Mixing 17 kmWestern PacificEastern Pacific O 3 (ppb) NO 2 (ppt) Cl y (ppt) Mixing ratio (ppb O 3, ppt NO 2 and Cl y ) Alt (km) 24 O 3 (ppb) NO 2 (ppt) Cl y (ppt)

25 Br y partitioning in the tropical tropopause O 3 NO 2 Cl y Solar Zenith Angle Mixing ratios NO 2 ( ppb)/Cl y (ppb)/O 3 (ppm) Mixing ratios (ppt) Daytwilight Night Day twilightNight WESTERN PACIFICEASTERN PACIFIC Br= 50.1 % BrO = 47.8 % BrONO 2 =50.1% BrCl= 57.7 % Br HBr BrONO 2 HOBr BrO BrCl Br y

III- Inter-hemispheric behavior of VSLBr 26

Inter-hemispheric sampling density WESTERN PACIFICEASTERN PACIFIC # Samples Alt (Km) NORTH (0 to 36 °N) SOUTH (0 to 11° S) 27 CH 2 BrCl CH 2 Br 2 CHBrCl 2 CHBr 2 Cl CHBr 3 CH 3 Br Halon 1211 Halon 2402

Inter-hemispheric Inter-hemispheric VSLBr distribution from GWAS and CAM-Chem WESTERN PACIFICEASTERN PACIFIC NORTH SOUTH Pmol Br/mol Alt (Km) 3.28 ± ± ± ± Minor VSLBr CHBr 3 CH 2 Br 2 VSL org

Summary The Total Organic Bromine budget is approximately the same at 17 km (Θ ~ 370K) in the Eastern and Western Pacific ( ~ 18 ppt) In the less convective region (Eastern Pacific) VSL org could have more time to react and produce ~1.5 times more Br y than in the most convective region (Western Pacific) Higher emissions of VSL org in Eastern Pacific could compensate the losses due to reaction, and keep a similar amount of VSL org in both regions of the Pacific (~ 3.8 ppt) The amount of VSLBr that reaches the stratosphere (17 Km) of the Eastern and Western Pacific is similar (~6 (4-9 ppt). The range observed in this study is significant narrow the one proposed by WMO 2014, particularly at the lower level. Partition of Br y species is different in the Eastern and Western Pacific. According to our model, during the day, Br is the dominant species the Western Pacific, while BrO dominates the Eastern Pacific. However, during the night, BrCl dominates in the West and BrONO 2 dominates in the East. We don’t have enough samples from ATTREX to identify a significant interhemispheric difference in organic bromine. 29

Thank you and Questions

31 EXTRA SLIDES

32

Variability and Distribution of GWAS organic bromine species WESTERN PACIFICEASTERN PACIFIC Mixing ratios (pmol/mol) ALT (mts) Bin 1Km Alt Error =1sd Halon 1211 Halon 2402 CH 3 Br % 0.03% 1.96% 1.3% 0.7 %

Variability and Distribution of GWAS organic bromine species WESTERN PACIFICEASTERN PACIFIC Mixing ratios (pmol/mol) ALT (mts) CHBR3 CH2Br2 CHBR 2 Cl CH 2 BrCl CHBrCl 2 Bin 1Km Alt Error =1sd 34 60% 22% 46% 4 % 16% 33 % 7 % 4 % 49% 17%

Organic Bromine Budget in TTL (15-17Km) WESTERN PACIFICEASTERN PACIFIC CHBrCl2 46 CHBr2Cl 56 CH2BrCl 145 CH3Br Total Halon VSLorg VERY SHORT LIVED Br (VSLorg) = (3* CHBr 3 )+ (2* CH 2 Br 2 ) + Minor VSLBr days 35

36 Average Br org =18.48± x.xx pmol Br/mol Average Br org =18.19± x.xx pmol Br/mol pmol Br/mol Alt (Km) Bin 1Km Alt Error =1sd 36 CH3Br Total Halons VSLorg CAM-Chem GWAS Organic Bromine Budget in TTL (15-17Km) Upper TTL Lower TTL