Atmospheric CO₂ from Flask Air Samples at Alert, Canada

Graphics    Digital Data

C.D. Keeling and T.P. Whorf

Carbon Dioxide Research Group, Scripps Institution of Oceanography, University of California, La Jolla, California 92093-0444, U.S.A.

Period of Record

1985-2001

Methods

Atmospheric CO₂ samples have been collected approximately weekly since 1985. Samples are collected in 5-L evacuated gas flasks, and then returned to the Scripps Institution of Oceanography (SIO) where CO₂ concentrations have been determined using an Applied Physics Corporation (APC) nondispersive infrared gas analyzer. Further information on measurements, calibration procedures, and analysis is available in the references listed below.

Alert, Northwest Territories, Canada
Tundra (snow covered for almost
three quarters of the year)
82°28' N, 62°30' W
210 m above MSL

Trends

The average of unflagged data for the first year of measurements (1986) was 348.9 ppmv; 2001 values averaged 372.4 ppmv for an upward trend of 1.57 ppmv/year. Graphics here show the first and last year of data to display the change in mean over time and the annual amplitudes. Long term trend curves are better displayed using SIO's monthly averaged data.

References

• Guenther, P.R., A. Bollenbacher, C.D. Keeling, and D. Moss. 2002 Technical Report: Infrared Analyses of NOAA Primary CO₂-in-Air Reference Gas Standards at SIO, 1991-1999.
• Keeling, C.D., R.B. Bacastow, A.F. Carter, S.C. Piper, T.P. Whorf, M. Heimann, W.G. Mook, and H. Roeloffzen. 1989. A three-dimensional model of atmospheric CO₂ transport based on observed winds: 1. Analysis of observational data. In D.H. Peterson (ed.), Aspects of Climate Variability in the Pacific and the Western Americas, 165-236, Geophysical Monograph 55, American Geophysical Union, Washington, DC.
• Keeling, C.D., T.P. Whorf, M. Wahlen & J. van der Plicht. 1995. Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980, Nature 375, 666-670.
• Keeling, C.D., S.C. Piper, R.B. Bacastow, M. Wahlen, T.P. Whorf, M. Heimann, and H.A. Meijer. 2001. Exchanges of Atmospheric CO₂ and ¹³CO₂ with the Terrestrial Biosphere and Oceans from 1978 to 2000. I. Global Aspects. SIO Reference No. 01-06 (Revised from SIO Reference No. 00-21), June 2001.
• Keeling, C.D., P.R. Guenther, G. Emanuele III, A. Bollenbacher, and D.J. Moss. 2002. Scripps Reference Gas Calibration System for Carbon Dioxide-in-Nitrogen and Carbon Dioxide-in-Air Standards: Revision of 1999 (with Appendix and Addendum). SIO Reference Series No. 01-11.
  See Diagram of the constant-volume mercury-column manometer.

10/2004