Continuous measurements of methane mixing ratios from ice cores

This work presents a new, field-deployable technique for continuous, high-resolution measurements of methane mixing ratios from ice cores. The technique is based on a continuous flow analysis system, where ice core samples cut along the long axis of an ice core are melted continuously. The past atmo...

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Main Authors: C. Stowasser, C. Buizert, V. Gkinis, J. Chappellaz, S. Schüpbach, M. Bigler, X. Faïn, P. Sperlich, M. Baumgartner, A. Schilt, T. Blunier
Format: Article
Language:English
Published: Copernicus Publications 2012-05-01
Series:Atmospheric Measurement Techniques
Online Access:http://www.atmos-meas-tech.net/5/999/2012/amt-5-999-2012.pdf
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author C. Stowasser
C. Buizert
V. Gkinis
J. Chappellaz
S. Schüpbach
M. Bigler
X. Faïn
P. Sperlich
M. Baumgartner
A. Schilt
T. Blunier
author_facet C. Stowasser
C. Buizert
V. Gkinis
J. Chappellaz
S. Schüpbach
M. Bigler
X. Faïn
P. Sperlich
M. Baumgartner
A. Schilt
T. Blunier
author_sort C. Stowasser
collection DOAJ
description This work presents a new, field-deployable technique for continuous, high-resolution measurements of methane mixing ratios from ice cores. The technique is based on a continuous flow analysis system, where ice core samples cut along the long axis of an ice core are melted continuously. The past atmospheric air contained in the ice is separated from the melt water stream via a system for continuous gas extraction. The extracted gas is dehumidified and then analyzed by a Wavelength Scanned-Cavity Ring Down Spectrometer for methane mixing ratios. We assess the performance of the new measurement technique in terms of precision (±0.8 ppbv, 1σ), accuracy (±8 ppbv), temporal (ca. 100 s), and spatial resolution (ca. 5 cm). Using a firn air transport model, we compare the resolution of the measurement technique to the resolution of the atmospheric methane signal as preserved in ice cores in Greenland. We conclude that our measurement technique can resolve all climatically relevant variations as preserved in the ice down to an ice depth of at least 1980 m (66 000 yr before present) in the North Greenland Eemian Ice Drilling ice core. Furthermore, we describe the modifications, which are necessary to make a commercially available spectrometer suitable for continuous methane mixing ratio measurements from ice cores.
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spelling doaj.art-efe39805af6545bdb5c8933363b3351c2022-12-22T01:11:40ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482012-05-0155999101310.5194/amt-5-999-2012Continuous measurements of methane mixing ratios from ice coresC. StowasserC. BuizertV. GkinisJ. ChappellazS. SchüpbachM. BiglerX. FaïnP. SperlichM. BaumgartnerA. SchiltT. BlunierThis work presents a new, field-deployable technique for continuous, high-resolution measurements of methane mixing ratios from ice cores. The technique is based on a continuous flow analysis system, where ice core samples cut along the long axis of an ice core are melted continuously. The past atmospheric air contained in the ice is separated from the melt water stream via a system for continuous gas extraction. The extracted gas is dehumidified and then analyzed by a Wavelength Scanned-Cavity Ring Down Spectrometer for methane mixing ratios. We assess the performance of the new measurement technique in terms of precision (±0.8 ppbv, 1σ), accuracy (±8 ppbv), temporal (ca. 100 s), and spatial resolution (ca. 5 cm). Using a firn air transport model, we compare the resolution of the measurement technique to the resolution of the atmospheric methane signal as preserved in ice cores in Greenland. We conclude that our measurement technique can resolve all climatically relevant variations as preserved in the ice down to an ice depth of at least 1980 m (66 000 yr before present) in the North Greenland Eemian Ice Drilling ice core. Furthermore, we describe the modifications, which are necessary to make a commercially available spectrometer suitable for continuous methane mixing ratio measurements from ice cores.http://www.atmos-meas-tech.net/5/999/2012/amt-5-999-2012.pdf
spellingShingle C. Stowasser
C. Buizert
V. Gkinis
J. Chappellaz
S. Schüpbach
M. Bigler
X. Faïn
P. Sperlich
M. Baumgartner
A. Schilt
T. Blunier
Continuous measurements of methane mixing ratios from ice cores
Atmospheric Measurement Techniques
title Continuous measurements of methane mixing ratios from ice cores
title_full Continuous measurements of methane mixing ratios from ice cores
title_fullStr Continuous measurements of methane mixing ratios from ice cores
title_full_unstemmed Continuous measurements of methane mixing ratios from ice cores
title_short Continuous measurements of methane mixing ratios from ice cores
title_sort continuous measurements of methane mixing ratios from ice cores
url http://www.atmos-meas-tech.net/5/999/2012/amt-5-999-2012.pdf
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