Lower stratospheric organic and inorganic bromine budget for the Arctic winter 1998/99

In the Arctic winter 1998/99, two balloon payloads were launched in a co-ordinated study of stratospheric bromine. Vertical profiles (9-28 km) of all known major organic Br species (CH 3 Br, C 2 H 5 Br, CH 2 BrCl, CHBrCl 2 , CH 2 Br 2 , CHBr 2 Cl, CHBr 3 , H1301, H1211, H2402, and H1202) were measured, and total organic Br (henceforth called Br org y ) originating from these organic precursors was inferred as a function of altitude. This was compared with total inorganic reactive Br (henceforth called Br in y ) derived from spectroscopic BrO observations, after accounting for modeled stratospheric Br y partitioning. Within the studied altitude range the two profiles differed by less than the estimated accumulated uncertainties. This good agreement suggests that the lower stratospheric budget and chemistry of Br is well understood for the specified conditions. For early 1999 our data suggest 2 Br in y mixing ratio of 1.5 ppt in air just above the local Arctic tropopause (∼ 9.5 km), whilst at 25 km in air of 5.6 yr mean age it was estimated to be 18.4(+1.8/-1.5) ppt from organic precursor measurements, and (21.5±3.0) ppt from BrO measurements and photochemical modelling, respectively. This suggests a Br in y influx of 3.1(-2.9/+3.5) ppt from the troposphere to the stratosphere.

[1]  Ulrich Platt,et al.  Short‐lived alkyl iodides and bromides at Mace Head, Ireland: Links to biogenic sources and halogen oxide production , 1999 .

[2]  C. Rinsland,et al.  Stratospheric N2O5, CH4, and N2O profiles from IR solar occultation spectra , 1993 .

[3]  K. Pfeilsticker,et al.  Differential optical absorption spectroscopy instrument for stratospheric balloonborne trace-gas studies. , 2000, Applied optics.

[4]  D. Blake,et al.  Distributions of brominated organic compounds in the troposphere and lower stratosphere , 1999 .

[5]  A. Engel,et al.  CO2 and SF6 as stratospheric age tracers: Consistency and the effect of mesospheric SF6‐loss , 2000 .

[6]  W. Sturges,et al.  Bromoform as a source of stratospheric bromine , 2000 .

[7]  Ulrich Platt,et al.  Differential optical absorption spectroscopy (DOAS) , 1994 .

[8]  Franck Lefèvre,et al.  First direct simultaneous HCl and ClONO2 profile measurements in the Arctic Vortex , 1998 .

[9]  S. Solomon,et al.  Rethinking reactive halogen budgets in the midlatitude lower stratosphere , 1999 .

[10]  D. Weisenstein,et al.  Distribution of halon-1211 in the upper troposphere and lower stratosphere and the 1994 total bromine budget , 1998 .

[11]  A. Engel,et al.  Partitioning Between Chlorine Reservoir Species Deduced from Observations in the Arctic Winter Stratosphere , 1997 .

[12]  I. Levin,et al.  Global increase of SF6 observed in the atmosphere , 1994 .

[13]  M. Chipperfield,et al.  Comparison of measured and modeled stratospheric BrO: Implications for the total amount of stratospheric bromine , 2000 .

[14]  Jürgen M. Lobert,et al.  Growth and distribution of halons in the atmosphere , 1998 .

[15]  S. Schauffler,et al.  Measurements of bromine containing organic compounds at the tropical tropopause , 1998 .

[16]  D. Weisenstein,et al.  On the relation between stratospheric chlorine/bromine loading and short-lived tropospheric source gases , 1997 .

[17]  S. Solomon,et al.  Measurements of halogenated organic compounds near the tropical tropopause , 1993 .

[18]  K. Pfeilsticker,et al.  Stratospheric BrO profiles measured at different latitudes and seasons: Instrument description, spectral analysis and profile retrieval , 1998 .

[19]  M. Chipperfield,et al.  First profile measurements of tropospheric BrO , 2000 .

[20]  Martyn P. Chipperfield,et al.  Multiannual simulations with a three‐dimensional chemical transport model , 1999 .

[21]  Stuart A. Penkett,et al.  Southern Hemispheric halon trends (1978-1998) and global halon emissions , 1999 .

[22]  D. Thomson,et al.  Halogen ions and NO+ in the mass spectra of aerosols in the upper troposphere and lower stratosphere , 2000 .

[23]  Y. Yokouchi,et al.  Latitudinal distribution of atmospheric methyl bromide: Measurements and modeling , 2000 .

[24]  K. Pfeilsticker,et al.  Stratospheric BrO profiles measured at different latitudes and seasons: Atmospheric observations , 1998 .