CSIRO ATMOSPHERIC RESEARCH, GASLAB FLASK CO2 DATA RELEASE DATE: OCTOBER 2002 CONTACTS: Paul Steele, CSIRO Atmospheric Research, Private Bag 1, Aspendale, Victoria, Australia 3195 Telephone: (+613) 9239 4578 Fax: (+613) 9239 4444 e-mail: paul.steele@csiro.au Paul Krummel, CSIRO Atmospheric Research, Private Bag 1, Aspendale, Victoria, Australia 3195 Telephone: (+613) 9239 4568 Fax: (+613) 9239 4444 e-mail: paul.krummel@csiro.au Ray Langenfelds, CSIRO Atmospheric Research, Private Bag 1, Aspendale, Victoria, Australia 3195 Telephone: (+613) 9239 4598 Fax: (+613) 9239 4444 e-mail: ray.langenfelds@csiro.au NOTICE: * The current version of the data represents the highest quality we can provide at this time, in terms of alignment to a calibration scale, internal consistency and precision. However, any data version should be considered provisional only. Adjustments may be made in the future, as new or improved information becomes available. * Please contact us at the above E-mail addresses if any clarification of the meaning or limitations of the data is required. If users wish to send us preprints of any publications using the data, we would be happy to check that the data are being used within their limitations. * We ask that use of this data in any paper or presentation be accompanied by acknowledgement of the source of the data (CSIRO Atmospheric Research GASLAB) and that the version of the data (as specified by release date) be explicitly stated. SAMPLING: The listed data have been obtained from flask air samples returned to GASLAB for analysis. The flasks are of 5 types: (i) glass 0.5 litre, sealed with two stopcocks fitted with PTFE, PFA or Viton O-rings (flask identifier prefix "G050"), (ii) glass 5.0 litre, sealed with two stopcocks fitted with PTFE O-rings ("G500"), (iii) glass 0.8 litre, sealed with two stopcocks fitted with PTFE or PFA O-rings ("G080"), (iv) electropolished stainless steel 1.6 litre "Sirocans" fitted with two stainless steel valves manufactured by either Nupro or Hoke ("S160"), (v) glass 2.0 litre sealed with a single stopcock fitted with a Viton O-ring ("F", "FF", "FA," "FE", "EP", ALT")and provided by the Meteorological Service of Canada for air sampling at the Canadian sites, Alert, Estevan Point and Fraserdale. Experiments carried out to test for changes in sample CO2 mixing ratio during storage have shown significant drifts in some flask types over test periods of several months to years (Cooper et al., 1999). Corrections derived from the test results are applied to network data according to flask type. Typical sample storage times range from days to weeks for some sites (e.g. Cape Grim, Aircraft) to as much as 1 year for Macquarie Island and the Antarctic sites. ANALYSIS: Samples were analysed by gas chromatography with flame ionisation detection after methanization of CO2 to CH4. One Carle gas chromatograph, labelled "Carle-3" (C3) was used over the length of the record. Data are reported here in the WMO CO2 mole fraction calibration scale. Further details are provided elsewhere of CSIRO's global sampling network, sampling and analytical techniques (Francey et al., 1996), and measurement uncertainty (Langenfelds et al., 2001a). CALIBRATION: Data are reported in the WMO CO2 Mole Fraction Scale. The link to this scale was established with 9 `primary' high-pressure cylinder standards of synthetic mixtures of CO2, CH4 and CO in zero (natural) air calibrated by NOAA/CMDL in 1992, with a subset recalibrated in 1994. The relative stability of the primary suite is monitored using frequent comparisons with about 15 long-lived secondary standards. The link to the international scale is monitored by a variety of on- going comparisons involving high-pressure cylinder standards (WMO Round Robins, IAEA CLASSIC, cylinder exchanges with NOAA, etc.), as well as 6-per-month flask-air-sharing comparisons of samples collected at Cape Grim. More detailed calibration information is given by Langenfelds et al. (2001a). DATA PROCESSING: Flask data are assigned flags to indicate whether they are classified as retained or rejected. Cause of rejection falls into three broad categories: (i) the sample is considered to be not representative of the atmosphere at the time and place of sampling due to identified or inferred sampling or analytical problems (eg. sample contamination, poor analysis), (ii) the sample is considered to be "non-baseline" as indicated by the meteorological conditions at the time of sampling and (iii) any remaining outliers are flagged on the basis of a 3-sigma filter (geographically fixed sites only). For completeness, all data are included here, regardless of whether they are retained or rejected. Please note that for routine "baseline" applications, any rejected data must be actively excluded from the provided data sets, while for "non- baseline" applications data flagged under categories (ii) and (iii) above may carry biogeochemical information (see DATA FORMAT section below). Also, further data selection may be desirable for those data sets that cannot be screened by the 3-sigma filter (e.g. AIA; aircraft). DATA FILES: Data are provided for samples collected at the following geographically fixed sites: ALC - Alert, Canada (82 27'N, 62 31'W, 6 metres altitude) CFA - Cape Ferguson, Australia (19 17'S, 147 03'E, 2 m) CGA - Cape Grim, Australia (40 41'S, 144 41'E, 94 m) EPC - Estevan Point, Canada (49 23'N, 126 32'W, 39 m) MAA - Mawson, Australia (67 37'S, 62 52'E, 32 m) MLU - Mauna Loa, Hawaii, USA (19 32'N, 155 35'W, 3397 m) MQA - Macquarie Island, Australia (54 29'S, 158 58'E, 12 m) SIS - Shetland, Scotland (60 10'N, 01 10'W, 30 m) SPU - South Pole, Antarctica (89 59'S, 24 48'W, 2810 m) and from the following moving platforms: AIA - Aircraft (over Bass Strait and Cape Grim) Files containing a single CO2 value for each sample are provided for each site code (e.g. cga.co2). For the geographically fixed sites, data are also provided in the form of monthly means (e.g. cga_mm.co2), which are calculated as the mean of daily values from a smooth curve fit to the data using the curve-fitting routines described by Thoning et al. (1989). DATA FORMATS: Files listing individual flask data are provided in the following format. Note that altitude, latitude and longitude coordinates are only included for moving platform sites. Sign conventions employed for position coordinates are positive for latitudes north and longitudes east. sss yyyy mm dd hh mm xxxx-xxx c nnnnn.nn fff ii YYYY MM DD HH MM uuuuuu aaaaa ttt.tttt gggg.gggg sss three-letter site code yyyy mm dd collection date (year, month, day; UT) hh mm collection time (hour, minute; UT) xxxx-xxx flask identifier c sample collection method code (for the retained data: A = GASLAB flask pump unit (FPU) with anhydrous Mg(ClO4)2 drying, D = metal bellows pump with anhydrous Mg(ClO4)2 drying, C = manual aircraft sampling unit with anhydrous Mg(ClO4)2 drying, H = automated aircraft sampling unit with anhydrous Mg(ClO4)2 drying, 6 = method not directly recorded) nnnnn.nn CO2 mixing ratio (ppm) fff flags: "..." indicates no flags, sample retained. Any entry other than "." in the first flag column indicates the sample is not representative of the time and place of sampling: A = no sample taken B = sample lost before analysis C = identified sampling error D = suspected sampling problem (eg. 2 or more species give anomalous values) E = mixed samples (time/place not unique) N = unacceptable analysis * = no analysis data available H = species-specific manually applied rejection flag I = species-specific sample collection problem J = irretrievable sample storage effect . = not subject to any of the above flags Any entry other than "." in the second flag column indicates the sample is non-baseline, rejected only on grounds of being an outlier or is excluded from this data set because of a non-standard sampling technique. F = non-baseline meteorological conditions G = marginal-baseline meteorological conditions K = species-specific non-baseline meteorological conditions L = species-specific marginal-baseline meteorological conditions M = 3 sigma filter rejected O = non-standard sampling technique . = not subject to any of the above flags ii analytical instrument code YYYY MM DD HH MM first analysis date and time uuuuuu Universal Analysis Number (UAN; a number that uniquely identifies each sample) For aircraft samples only: aaaaa altitude (metres) ttt.tttt latitude (decimal degrees) gggg.gggg longitude (decimal degrees) Files listing the monthly mean data are provided in the following format: yyyy mm nnnn.nn yyyy year mm month nnnn.nn CO2 (ppm) REFERENCES: Cooper, L.N., L.P. Steele, R.L. Langenfelds, D.A. Spencer and M.P. Lucarelli. Atmospheric methane, carbon dioxide, hydrogen, carbon monoxide and nitrous oxide from Cape Grim flask air samples analysed by gas chromatography. Baseline Atmospheric Program (Australia) 1996, edited by J.L. Gras, N. Derek, N.W. Tindale and A.L. Dick, pp 98 - 102, Bureau of Meteorology and CSIRO Atmospheric Research, Melbourne, Australia, 1999. Francey, R.J., L.P. Steele, R.L. Langenfelds, M.P Lucarelli, C.E. Allison, D.J. Beardsmore, S.A. Coram, N. Derek, F.R. de Silva, D.M. Etheridge, P.J. Fraser, R.J. Henry, B. Turner, E.D. Welch, D.A. Spencer and L.N. Cooper. Global Atmospheric Sampling Laboratory (GASLAB): supporting and extending the Cape Grim trace gas programs. Baseline Atmospheric Program (Australia) 1993, edited by R.J. Francey, A.L. Dick and N. Derek, pp 8 - 29, Bureau of Meteorology and CSIRO Division of Atmospheric Research, Melbourne, Australia, 1996. Francey, R.J., L.P. Steele, R.L. Langenfelds, C.E. Allison, L.N. Cooper. B.L. Dunse, B.G. Bell, T.D. Murray, H.S. Tait, L. Thompson and K.A. Masarie. Atmospheric carbon dioxide and its isotopes, methane, carbon monoxide, nitrous oxide and hydrogen from Shetland. Atmos. Environ., 32, 3331-3338, 1998. Francey, R.J., L.P. Steele, R.L. Langenfelds and B.C. Pak, High precision long-term monitoring of radiatively active trace gases at surface sites and from ships and aircraft in the Southern Hemisphere atmosphere. J. Atmos. Science., 56, 279-285, 1999. Fraser, P.J., S.A. Coram and N. Derek. Atmospheric methane, carbon monoxide and carbon dioxide by gas chromatography. Baseline Atmospheric Program (Australia) 1991, edited by A.L. Dick and J.L. Gras, pp 60 - 64, Bureau of Meteorology and CSIRO Division of Atmospheric Research, Melbourne, Australia, 1994. Langenfelds, R.L., R.J. Francey, L.P. Steele, P.J. Fraser, S.A. Coram, M.R. Hayes, D.J. Beardsmore, M.P. Lucarelli, and F.R. de Silva, Improved vertical sampling of the trace gas composition of the troposphere above Cape Grim since 1991, in Baseline Atmospheric Program (Australia) 1993, edited by R.J. Francey, A.L. Dick and N. Derek, pp 45-56, Bureau of Meteorology and CSIRO Division of Atmospheric Research, Melbourne, Australia, 1996. Langenfelds, R.L., L.P. Steele, C.E. Allison and R.J. Francey, GASLAB Calibration Information, 2001. Internal Report, CSIRO Atmospheric Research, Aspendale, Australia, 2001a. Langenfelds, R.L., L.N. Cooper, L.P. Steele, D.A. Spencer, P.B. Krummel and P.J. Fraser. Atmospheric methane, carbon dioxide, hydrogen, carbon monoxide and nitrous oxide from Cape Grim flask air samples analysed by gas chromatography. Baseline Atmospheric Program (Australia) 1997-98, edited by N.W. Tindale, N. Derek, and R.J. Francey, pp 69 - 74, Bureau of Meteorology and CSIRO Atmospheric Research, Melbourne, Australia, 2001b. Langenfelds, R.L., R.J. Francey, L.P. Steele, D.A. Spencer and B.L. Dunse, Flask sampling from Cape Grim overflights, in Baseline Atmospheric Program (Australia) 1997-98, edited by N.W. Tindale, N. Derek and R.J. Francey, pp 74 - 84, Bureau of Meteorology and CSIRO Atmospheric Research, Melbourne, Australia, 2001c. Langenfelds, R.L., R.J. Francey, B.C. Pak, L.P. Steele, J. Lloyd, C.M. Trudinger and C.E. Allison, The use of multi-species measurements for interpreting interannual variability in the carbon cycle, 6th International CO2 Conference: extended abstracts, Sendai, Japan, 9-11, 2001d. Langenfelds, R.L., R.J. Francey, B.C. Pak, L.P. Steele, J. Lloyd, C.M. Trudinger and C.E. Allison, Interannual growth rate variations of atmospheric CO2 and its 13C, H2, CH4 and CO between 1992 and 1999 linked to biomass burning, Glob. Biogeochem. Cycles, 16(3) pages 21-1 to 21-22, 2002. Masarie, K.A., R.L. Langenfelds, C.E. Allison, T.J. Conway, E.J. Dlugokencky, R.J. Francey, P.C. Novelli, L.P. Steele, P.P. Tans, B. Vaughn and J.W.C. White, NOAA/CSIRO Flask Air Intercomparison Experiment: A strategy for directly assessing consistency among atmospheric measurements made by independent laboratories, J. Geophys. Res., 106, 20445-20464, 2001. Pak, B.C., R.L. Langenfelds, R.J. Francey, L.P. Steele and I. Simmonds, A climatology of trace gases from the Cape Grim overflights, 1992 - 1995, in Baseline Atmospheric Program (Australia) 1994-5, edited by R.J. Francey, A.L. Dick and N. Derek, pp 41 - 52, Bureau of Meteorology and CSIRO Division of Atmospheric Research, Melbourne, Australia, 1996. Pak, B.C., Vertical structure of atmospheric trace gases over Southeast Australia, PhD Thesis, University of Melbourne, Australia, 273 pp. (available at the Australian Digital Theses Project via http://adt1.lib.unimelb.edu.au/adt-root/public/), 2000. Steele, L.P., R.L. Langenfelds, M.P. Lucarelli, P.J. Fraser, L.N. Cooper, D.A. Spencer, S. Chea and K. Broadhurst. Atmospheric methane, carbon dioxide, carbon monoxide, hydrogen and nitrous oxide from Cape Grim flask air samples analysed by gas chromatography. Baseline Atmospheric Program (Australia) 1994-95, edited by R.J. Francey, A.L. Dick and N. Derek, pp 107 - 110, Bureau of Meteorology and CSIRO Division of Atmospheric Research, Melbourne, Australia, 1996. Thoning, K.W., P.P. Tans and W.D. Komhyr, Atmospheric carbon dioxide at Mauna Loa Observatory, 2, Analysis of the NOAA/GMCC data, 1974 - 1985, J. Geophys. Res., 94, 8549- 8565, 1989.