A tropical West Pacific OH minimum and implications for stratospheric composition
Item
Title (Dublin Core)
A tropical West Pacific OH minimum and implications for stratospheric composition
Description (Dublin Core)
Most of the short-lived biogenic and anthropogenic chemical species that are emitted into the atmosphere break down efficiently by reaction with OH and do not reach the stratosphere. Here we show the existence of a pronounced minimum in the tropospheric column of ozone over the West Pacific, the main source region for stratospheric air, and suggest a corresponding minimum of the tropospheric column of OH. This has the potential to amplify the impact of surface emissions on the stratospheric composition compared to the impact when assuming globally uniform OH conditions. Specifically, the role of emissions of biogenic halogenated species for the stratospheric halogen budget and the role of increasing emissions of SO<sub>2</sub> in Southeast Asia or from minor volcanic eruptions for the increasing stratospheric aerosol loading need to be reassessed in light of these findings. This is also important since climate change will further modify OH abundances and emissions of halogenated species. Our study is based on ozone sonde measurements carried out during the TransBrom cruise with the RV <i>Sonne</i> roughly along 140–150° E in October 2009 and corroborating ozone and OH measurements from satellites, aircraft campaigns and FTIR instruments. Model calculations with the GEOS-Chem Chemistry and Transport Model (CTM) and the ATLAS CTM are used to simulate the tropospheric OH distribution over the West Pacific and the transport pathways to the stratosphere. The potential effect of the OH minimum on species transported into the stratosphere is shown via modeling the transport and chemistry of CH<sub>2</sub>Br<sub>2</sub> and SO<sub>2</sub>.
Creator (Dublin Core)
Rex, M.
Wohltmann, I.
Ridder, T.
Lehmann, R.
Rosenlof, K.
Wennberg, P.
Weisenstein, D.
Notholt, J.
Krüger, K.
Mohr, V.
Tegtmeier, S.
Date (Dublin Core)
2018-09-06
Type (Dublin Core)
info:eu-repo/semantics/Text
Format (Dublin Core)
info:eu-repo/semantics/application/pdf
Identifier (Dublin Core)
10.5194/acp-14-4827-2014
https://acp.copernicus.org/articles/14/4827/2014/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
Relation (Dublin Core)
info:eu-repo/grantAgreement/EC/FP7/226224
Rights (Dublin Core)
info:eu-repo/semantics/openAccess
