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

Citation
K. Pfeilsticker et al., Lower stratospheric organic and inorganic bromine budget for the Arctic winter 1998/99, GEOPHYS R L, 27(20), 2000, pp. 3305-3308
Citations number
25
Categorie Soggetti
Earth Sciences
Journal title
GEOPHYSICAL RESEARCH LETTERS
ISSN journal
00948276 → ACNP
Volume
27
Issue
20
Year of publication
2000
Pages
3305 - 3308
Database
ISI
SICI code
0094-8276(20001015)27:20<3305:LSOAIB>2.0.ZU;2-O
Abstract
In the Arctic winter 1998/99, two balloon payloads were launched in a co-or dinated study of stratospheric bromine. Vertical profiles (9-28 km) of all known major organic Br species (CH3Br, C2H5Br, CH2BrCl, CHBrCl2, CH2Br2, CH Br2Cl, CHBr3, H1301, H1211, H2402, and H1202) were measured, and total orga nic Br (henceforth called Br-y(org)) originating from these organic precurs ors was inferred as a function of altitude. This was compared with total in organic reactive Br (henceforth called Br-y(in)) derived from spectroscopic BrO observations, after accounting for modeled stratospheric Br-y partitio ning. Within the studied altitude range the two profiles differed by less t han the estimated accumulated uncertainties. This good agreement suggests t hat the lower stratospheric budget and chemistry of Br is well understood f or the specified conditions. For early 1999 our data suggest a Br-y(in) mix ing ratio of 1.5 ppt in air just above the local Arctic tropopause (similar to 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 pr cursor measurements, and (21.5+/-3.0 ) ppt from BrO measurements and photochemical modelling, respectively. This suggests a Br-y(in) influx of 3.1(-2.9/+3.5) ppt from the troposphere to t he stratosphere.