Skip to Main content Skip to Navigation
Journal articles

Long-lived halocarbon trends and budgets from atmospheric chemistry modelling constrained with measurements in polar firn

Abstract : The budgets of seven halogenated gases (CFC- 11, CFC-12, CFC-113, CFC-114, CFC-115, CCl4 and SF6) are studied by comparing measurements in polar firn air from two Arctic and three Antarctic sites, and simulation results of two numerical models: a 2-D atmospheric chemistry model and a 1-D firn diffusion model. The first one is used to calculate atmospheric concentrations from emission trends based on industrial inventories; the calculated concentration trends are used by the second one to produce depth concentration profiles in the firn. The 2-D atmospheric model is validated in the boundary layer by comparison with atmospheric station measurements, and vertically for CFC-12 by comparison with balloon and FTIR measurements. Firn air measurements provide constraints on historical atmospheric concentrations over the last century. Age distributions in the firn are discussed using a Green function approach. Finally, our results are used as input to a radiative model in order to evaluate the radiative forcing of our target gases. Multi-species and multi-site firn air studies allow to better constrain atmospheric trends. The low concentrations of all studied gases at the bottom of the firn, and their consistency with our model results confirm that their natural sources are small. Our results indicate that the emissions, sinks and trends of CFC-11, CFC-12, CFC-113, CFC-115 and SF6 are well constrained, whereas it is not the case for CFC-114 and CCl4. Significant emission-dependent changes in the lifetimes of halocarbons destroyed in the stratosphere were obtained. Those result from the time needed for their transport from the surface where they are emitted to the stratosphere where they are destroyed. Efforts should be made to update and reduce the large uncertainties on CFC lifetimes
Document type :
Journal articles
Complete list of metadatas

Cited literature [51 references]  Display  Hide  Download

https://hal-insu.archives-ouvertes.fr/insu-00421106
Contributor : Aurore Gayraud <>
Submitted on : Monday, February 27, 2012 - 1:36:40 PM
Last modification on : Friday, September 25, 2020 - 9:16:02 AM
Long-term archiving on: : Friday, November 23, 2012 - 2:52:05 PM

File

acp-9-3911-2009.pdf
Publisher files allowed on an open archive

Identifiers

Collections

Citation

Patricia Martinerie, E. Nourtier-Mazauric, Jean-Marc Barnola, W. Sturges, D. R. Worton, et al.. Long-lived halocarbon trends and budgets from atmospheric chemistry modelling constrained with measurements in polar firn. Atmospheric Chemistry and Physics, European Geosciences Union, 2009, 9 (12), pp.3911-3934. ⟨10.5194/acp-9-3911-2009⟩. ⟨insu-00421106⟩

Share

Metrics

Record views

664

Files downloads

454