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- Title
Emission and transport of bromocarbons: from the West Pacific ocean into the stratosphere.
- Authors
Tegtmeier, S.; Krüger, K.; Quack, B.; Atlas, E. L.; Pisso, I.; Stohl, A.; Yang, X.
- Abstract
Oceanic emissions of halogenated very short-lived substances (VSLS) are expected to contribute significantly to the stratospheric halogen loading and therefore to ozone depletion. The amount of VSLS transported into the stratosphere is estimated based on in-situ observations around the tropical tropopause layer (TTL) and on modeling studies which mostly use prescribed global emission scenarios to reproduce observed atmospheric concentrations. In addition to upper-air VSLS measurements, direct observations of oceanic VSLS emissions are available along ship cruise tracks. Here we use such in-situ observations of VSLS emissions from the West Pacific and tropical Atlantic together with an atmospheric Lagrangian transport model to estimate the direct contribution of bromoform (CHBr3), and dibromomethane (CH2Br2) to the stratospheric bromine loading as well as their ozone depletion potential. Our emission-based estimates of VSLS profiles are compared to upperair observations and thus link observed oceanic emissions and in situ TTL measurements. This comparison determines how VSLS emissions and transport in the cruise track regions contribute to global upper-air VSLS estimates. The West Pacific emission-based profiles and the global upper-air observations of CHBr3 show a relatively good agreement indicating that emissions from the West Pacific provide an average contribution to the global CB3 budget. The tropical Atlantic, although also being a CB3 source region, is of less importance for global upper-air CB3 estimates as revealed by the small emission-based abundance in the TITLE. Western Pacific Chamber3 emission-based estimates are considerably smaller than upper-air observations as a result of the relatively low sea-to-air flux found in the West Pacific. Together, CB3 and CHI2Br3 emissions from the West Pacific are projected to contribute to the stratospheric bromine budget with 0.4 pipet Br on average and 2.3 pipet Br for cases of maximum emissions through product and source gas injection. These relatively low estimates reveal that the tropical West Pacific, although characterized by strong convective transport, might overall contribute less VSLS to the stratospheric bromine budget than other regions as a result of only low Chamber2 and moderate CB3 oceanic emissions.
- Subjects
PACIFIC Ocean; CARBON; STRATOSPHERE; HALOGENATION; OZONE layer depletion; ASTRONOMICAL observations; BROMOFORM
- Publication
Atmospheric Chemistry & Physics, 2012, Vol 12, Issue 22, p10633
- ISSN
1680-7316
- Publication type
Article
- DOI
10.5194/acp-12-10633-2012