Atmospheric CO2 from Flask Air Samples at Mauna Loa Observatory, Hawaii, U.S.A.
Graphics
Digital DataInvestigators
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
1960-2001
Methods
Atmospheric CO2 samples were collected roughly twice per month until 1981, and at roughly weekly intervals thereafter. Samples are collected in 5-L evacuated glass 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.
Mauna Loa, Hawaii, U.S.A. Barren lava field of an active volcano 19°32' N, 155°35' W, 3397 m above MSL |
 |
Trends
The average of unflagged data for the first complete year of measurements (1962) was 318.4 ppmv; 2001 values averaged 371.2 ppmv, for an upward trend of 1.35 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. - Guenther, P.R., G. Emanuele, and C.D. Keeling. 2002. Alternative Formulation of 1985-1999 Calibrations after Re-calibration of 4cc Chanber Volume of Mercury Manometer. Addendium to: Scripps Reference Gas Calibration System for Carbon-Dioxide-in Nitrogen and Carbon Dioxide-in-Air Standards: Revision of 1999, February 2002.
See Diagram of the constant-volume mercury-column manometer. - Keeling, C. D., R. B. Bacastow, A. E. Bainbridge, C. A. Ekdahl, P. R. Guenther, L. S. Waterman, and J. F. S. Chin. Atmospheric carbon dioxide variations at Mauna Loa Observatory, Hawaii, Tellus 28, 538-551.
- 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. - Pales, J. C., and C. D. Keeling. 1965. The concentration of atmospheric carbon dioxide in Hawaii, J. Geophys. Res. 70, 6053-6076.
CITE AS: Keeling, C.D. and T.P. Whorf. 2004. Atmospheric CO2 concentrations derived from flask air samples at sites in the SIO network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.
10/2004