The atmospheric trace gas, methane (CH4), affects the radiative heat balance of the earth. The sources of atmospheric methane are not well understood. Large air samples (1000-1400 litres) of methane are collected from a compressor system at Arrival Heights annually (since 1989) and samples are analysed for methane concentrations, the isotopic ratios of 14C/ 13C and 13C/12C and the characteristics ... and fluxes of sources and sinks are assessed. Sample collection is aimed at the clean sector of the sky from the West through North to East, throughout the year. Measurements of methane carbon isotopes and its concentration in the atmosphere in Antarctica will help to determine the geographic variation, transport and the type and distribution of the sources of methane from the northern hemisphere.
In-situ flask sampling: CO2, CH4, CO, N2O, 13CO2, 14CH4, 13CO, C180, 14CO. gas samples are collected from a mast 95 meters above ground level) in North sectors wind conditions only and above 5 knots. There are high pressure(~1000 litres, 800psi in 30L cylinder) and low pressure (~5 litres, 25psi in 2 litre flask) flask samples taken. Aire samples in the tanks and flasks are shipped back to NZ annually. Analysis is performed at NIWA's GAS LAB located at Greta Point Wellington. Gas chromatography (GC) and isotope ratio mass spectrometry (IRMS) employed in analysis. Data is held internally by NIWA and in the WDCGG database.
All of the data is held by NIWA Ltd., New Zealand and is available via the ftp site listed on this page. The data is also available via the Global Atmospheric Watch, World Data Centre for Greenhouse Gases (WDCGG). Please contact Dr Gordon Brailsford for more information.
Lowe, D.C., Brenninkmeijer, C.A.M., Manning, M.R., Typer, S.C., Dlugokencky, E. and Steele, P. 1989. Carbon Isotopic composition of Atmospheric Methane. Transaction American Geophysical Union 70(43): 1017.
Lowe, D.C. Manning, M.R. Brenninkmeijer, C.A.M. Lassey, K.R. Carbon isotopic composition of atmospheric methane. in: Proceedings of the 12th International Clean Air Conference, ... Auckland, March 25-30, 1990.Gibson P. (ed) Auckland: Clean Air Society of Australia and New Zealand. 1990. pp.125-132 ISBN 0473008718
Lowe, D.C. Brenninkmeijer, C.A.M. Brailsford, G.W. Lassey, K.R. Gomez, A.J. Nisbet, E.G. Concentration and 13C records of atmospheric methane in New Zealand and Antarctica: evidence for changes in methane sources. Journal of geophysical research 99(D8): 16,913-16,925, 1994.
Brenninkmeijer, C.A. Lowe, D.C. Manning, M.R. Sparks, R.J. van Velthoven, P.F. The 13C, 14C and 18O isotopic composition of CO, CH4 and CO2 in the higher southern latitudes lower stratosphere. Journal of geophysical research 100(D12): 26,163-26,172, 1995.
Lassey, K.R. Lowe, D. Brailsford, G.W. Gomez, A.J. Brenninkmeijer, C.A.M. Manning, M.R. Nisbet, E.G. Atmospheric methane in the Southern Hemisphere: the recent decline in source strengths inferred from concentration and isotope data. in: Local climate change science, policy and mitigation strategies; proceedings of Air & Waste Management Association International Speciality Conference, April 1994, Phoenix, AZ.Mathai C.V. Stensland G. (eds) Phoenix: Air and Waste Management Association. 1994. pp.233-248
Brailsford, G.W., Lowe, D.C., Roberts, P.A., Bromley, A.M., Moss, R.C. and Ussler, W. 1995. Interannual variability of 13C in Atmospheric Methane in the Antarctic. EOS, Transactions American Geophysical Union (Abstracts Fall 1995 meeting paper A31D-11) 76(46): 100.
Manning, M.R. Pearman, G.I. Etheridge, D.M. Fraser, P.J. Lowe, D.C. Steele, L.P. Changing composition of the atmosphere. in: Greenhouse: coping with climate change.Bouma W.J. Pearman G.I. Manning M.R. (eds) Collingwood: CSIRO Australia. 1996. pp.3-26 ISBN 0643056882
Mak, J.E., Manning, M.R. and Lowe, D.C. 2000. Aircraft observations of δ13C of atmospheric methane over the Pacific in August 1991 and 1993: Evidence of an enrichment in 13CH4 in the Southern Hemisphere. Journal of Geophysical Research 105: 1329.
Lowe, D.C., Allan, W., Manning, M.R., Bromley, T., Brailsford, G., Ferretti, D., Gomes, A., Knobben, R., Martin, R., Mei,Z., Moss, R., Koshy, K. and Maata, M. 1999. Shipboard determinations of the distributions of 13C in atmospheric methane in the Pacific. Journal of Geophysical Research 104: 26, 125-126, 135.
Allan, W. Lowe, D.C. Gomez, A.J. Struthers, H. Brailsford, G.W. Interannual variation of 13C in tropospheric methane: implications for possible atomic chlorine sink in the marine boundary layer. Journal of geophysical research 110: D11306, 2005.
Brailsford, G.W. Interannual variability of 13C in atmospheric methane in the Antarctic. Eos 76(46): 100, 1995.