noaa-icecore-14173
NEEM-2011-S1 Ice Core 1800 Year Continuous Methane Data
Rhodes, R.H.; Faïn, X.; Stowasser, C.; Blunier, T.; Chappellaz, J.A.; McConnell, J.R.; Romanini, D.; Mitchell, L.E.; Brook, E.J.
NEEM-2011-S1 Ice Core 1800 Year Continuous Methane Data
2013-04-04
NCDC-Paleoclimatology
ONLINE Files
Pending
https://www.ncdc.noaa.gov/paleo/study/14173
Investigator
R.H.
Rhodes
Investigator
X.
Faïn
Investigator
C.
Stowasser
Investigator
T.
Blunier
Investigator
J.A.
Chappellaz
Investigator
J.R.
McConnell
Investigator
D.
Romanini
Investigator
L.E.
Mitchell
Investigator
E.J.
Brook
earth science
paleoclimate
climate forcing|ice cores
methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,null,optical feedback cavity enhanced absorption spectroscopy,N,null
earth science
paleoclimate
climate forcing|ice cores
methane,bulk atmosphere,null,parts per billion,null,climate forcing|ice cores,corrected,optical feedback cavity enhanced absorption spectroscopy,N,null
earth science
paleoclimate
ice cores
depth,null,null,meter,null,ice cores,null,null,N,null
earth science
paleoclimate
ice cores
gas age,null,null,year Common Era,null,ice cores,null,null,N,null
earth science
paleoclimate
ice core
atmospheric gas
geoscientificInformation
270 AD
1961 AD
1680 cal yr BP
-11 cal yr BP
Complete
77.45
77.45
-51.06
-51.06
Continent
North America
Greenland
NEEM>LATITUDE 77.45>LONGITUDE -51.06
None
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English
DOC/NOAA/NESDIS/NCEI
National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
https://www.ncdc.noaa.gov/data-access/paleoclimatology-data
DATA Center Contact
Bruce
Bauer
bruce.a.bauer@noaa.gov
paleo@noaa.gov
303-497-6280
303-497-6513
325 Broadway, E/NE31
Boulder
CO
80305-3328
USA
online
ASCII
Rachael H. Rhodes, Xavier Faïn, Christopher Stowasser, Thomas Blunier, Jerome Chappellaz, Joseph R. McConnell, Daniele Romanini, Logan E. Mitchell, Edward J. Brook. 2013.
Continuous methane measurements from a late Holocene Greenland ice core: Atmospheric and in-situ signals.
Earth and Planetary Science Letters, vol. 368, pp. 9-19.
DOI: 10.1016/j.epsl.2013.02.034
Ancient air trapped inside bubbles in ice cores can now be analysed for methane concentration utilising a laser spectrometer coupled to a continuous melter system. We present a new ultra-high resolution record of atmospheric methane variability over the last 1800 yr obtained from continuous analysis of a shallow ice core from the North Greenland Eemian project (NEEM-2011-S1) during a 4-week laboratory-based measurement campaign. Our record faithfully replicates the form and amplitudes of multi-decadal oscillations previously observed in other ice cores and demonstrates the detailed depth resolution (5.3 cm), rapid acquisition time (30 m day-1) and good long-term reproducibility (2.6%, 2sigma) of the continuous measurement technique.
In addition, we report the detection of high frequency ice core methane signals of non-atmospheric origin. Firstly, measurements of air from the firn-ice transition region and an interval of ice core dating from 1546-1560 AD (gas age) resolve apparently quasi-annual scale methane oscillations. Traditional gas chromatography measurements on discrete ice samples confirm these signals and indicate peak-to-peak amplitudes of ca. 22 parts per billion (ppb). We hypothesise that these oscillations result from staggered bubble close-off between seasonal layers of contrasting density during time periods of sustained multi-year atmospheric methane change. Secondly, we report the detection of abrupt (20-100 cm depth interval), high amplitude (35-80 ppb excess) methane spikes in the NEEM ice that are reproduced by discrete measurements. We show for the first time that methane spikes present in thin and infrequent layers in polar, glacial ice are accompanied by elevated concentrations of carbon- and nitrogen-based chemical impurities, and suggest that biological in-situ production may be responsible.
STUDY NOTES: Methane concentration from the Greenland NEEM-2011-S1 Ice Core from 71 to 408m depth (~270-1961AD).
Methane concentrations analysed online by laser spectrometer (SARA, Spectroscopy by Amplified Resonant Absorption,
developed at Laboratoire Interdisciplinaire de Physique, Grenoble, France) on gas extracted from an ice core
processed using a continuous melter system (Desert Research Institute). Methane data have a 5 second integration time
(raw data acquisition rate 0.6 Hz). Analytical precision, from Allan Variance test, is 0.9 ppb (2 sigma).
Long-term reproducibility is 2.6% (2 sigma). Gaps in the record are due to problems during online analysis.
Online analysis conducted August-September 2011.
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/neem/neem2011s1-ch4-outliers.txt
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/neem/neem2011s1-ch4-outliers-removed.txt
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/neem/neem2011s1-ch4.txt
GET DATA
https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/neem/neem2011s1-ch4-5yr.txt
USA/NOAA
DIF
Version 9.8.4
2018-12-11
2018-12-11