English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
 
 
DownloadE-Mail
  Can the carbon isotopic composition of methane be reconstructed from multi-site firn air measurements?

Sapart, C. J., Martinerie, P., Witrant, E., Chappellaz, J., van de Wal, R. S. W., Sperlich, P., et al. (2013). Can the carbon isotopic composition of methane be reconstructed from multi-site firn air measurements? Atmospheric Chemistry and Physics, 13, 6993-7005. doi:10.5194/acp-13-6993-2013.

Item is

Files

show Files
hide Files
:
BGC1861.pdf (Publisher version), 2MB
Name:
BGC1861.pdf
Description:
-
OA-Status:
Visibility:
Public
MIME-Type / Checksum:
application/pdf / [MD5]
Technical Metadata:
Copyright Date:
-
Copyright Info:
-
:
BGC1861D.pdf (Publisher version), 2MB
Name:
BGC1861D.pdf
Description:
Discussion paper
OA-Status:
Visibility:
Public
MIME-Type / Checksum:
application/pdf / [MD5]
Technical Metadata:
Copyright Date:
-
Copyright Info:
-

Locators

show
hide
Locator:
http://dx.doi.org/10.5194/acp-13-6993-2013 (Publisher version)
Description:
OA
OA-Status:

Creators

show
hide
 Creators:
Sapart, C. J., Author
Martinerie, P., Author
Witrant, E., Author
Chappellaz, J., Author
van de Wal, R. S. W., Author
Sperlich, Peter1, Author           
van der Veen, C., Author
Bernard, S., Author
Sturges, W. T., Author
Blunier, T., Author
Schwander, J., Author
Etheridge, D., Author
Röckmann, T., Author
Affiliations:
1Service Facility Stable Isotope, Dr. W. A. Brand, Max Planck Institute for Biogeochemistry, Max Planck Society, ou_1497772              

Content

show
hide
Free keywords: -
 Abstract: Methane is a strong greenhouse gas and large uncertainties exist concerning the future evolution of its atmospheric abundance. Analyzing methane atmospheric mixing and stable isotope ratios in air trapped in polar ice sheets helps in reconstructing the evolution of its sources and sinks in the past. This is important to improve predictions of atmospheric CH4 mixing ratios in the future under the influence of a changing climate. The aim of this study is to assess whether past atmospheric 13C(CH4) variations can be reliably reconstructed from firn air measurements. Isotope reconstructions obtained with a state of the art firn model from different individual sites show unexpectedly large discrepancies and are mutually inconsistent.We show that small changes in the diffusivity profiles at individual sites lead to strong differences in the firn fractionation, which can explain a large part of these discrepancies. Using slightly modified diffusivities for some sites, and neglecting samples for which the firn fractionation signals are strongest, a combined multisite inversion can be performed, which returns an isotope reconstruction that is consistent with firn data. However, the isotope trends are lower than what has been concluded from Southern Hemisphere (SH) archived air samples and highaccumulation ice core data.We conclude that with the current datasets and understanding of firn air transport, a high precision reconstruction of 13C of CH4 from firn air samples is not possible, because reconstructed atmospheric trends over the last 50 yr of 0.3–1.5‰ are of the same magnitude as inherent uncertainties in the method, which are the firn fractionation correction (up to 2‰ at individual sites), the Kr isobaric interference (up to 0.8 ‰, system dependent), inter-laboratory calibration offsets (0.2 ‰) and uncertainties in past CH4 levels (0.5 ‰).

Details

show
hide
Language(s):
 Dates: 2013-06-142013-07-24
 Publication Status: Published online
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: Other: BGC1861
DOI: 10.5194/acp-13-6993-2013
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: Atmospheric Chemistry and Physics
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Katlenburg-Lindau, Germany : European Geosciences Union
Pages: - Volume / Issue: 13 Sequence Number: - Start / End Page: 6993 - 7005 Identifier: ISSN: 1680-7316
CoNE: https://pure.mpg.de/cone/journals/resource/111030403014016