Tropospheric bromine chemistry: Implications for present and pre-industrial ozone and mercury
dc.contributor.author | Parrella, J.P. | |
dc.contributor.author | Jacob, D.J. | |
dc.contributor.author | Liang, Q. | |
dc.contributor.author | Zhang, Y. | |
dc.contributor.author | Mickley, L.J. | |
dc.contributor.author | Miller, B. | |
dc.contributor.author | Evans, M.J. | |
dc.contributor.author | Yang, X. | |
dc.contributor.author | Pyle, J.A. | |
dc.contributor.author | Theys, N. | |
dc.contributor.author | Van Roozendael, M. | |
dc.date | 2012 | |
dc.date.accessioned | 2016-03-29T10:07:36Z | |
dc.date.available | 2016-03-29T10:07:36Z | |
dc.identifier.uri | https://orfeo.belnet.be/handle/internal/2985 | |
dc.description | We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1–8 nmol mol−1 (6.5% globally), with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT) to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic. | |
dc.language | eng | |
dc.title | Tropospheric bromine chemistry: Implications for present and pre-industrial ozone and mercury | |
dc.type | Article | |
dc.subject.frascati | Earth and related Environmental sciences | |
dc.audience | Scientific | |
dc.subject.free | atmospheric chemistry | |
dc.subject.free | atmospheric modeling | |
dc.subject.free | atmospheric transport | |
dc.subject.free | bromine | |
dc.subject.free | concentration (composition) | |
dc.subject.free | mercury (element) | |
dc.subject.free | ozone | |
dc.subject.free | seasonality | |
dc.subject.free | troposphere | |
dc.subject.free | Arctic | |
dc.subject.free | Atlantic Ocean | |
dc.subject.free | Atlantic Ocean (North) | |
dc.source.title | Atmospheric Chemistry and Physics | |
dc.source.volume | 12 | |
dc.source.issue | 15 | |
dc.source.page | 6723-6740 | |
Orfeo.peerreviewed | Yes | |
dc.identifier.doi | 10.5194/acp-12-6723-2012 | |
dc.identifier.scopus | 2-s2.0-84864595860 |