Atmospheric carbon dioxide records from sites in the NOAA/CMDL air sampling network

NIWOT RIDGE

Trends

The sampling site at Niwot Ridge is operated in cooperation with the University of Colorado's Institute of Arctic and Alpine Research (INSTAAR). The NOAA/CMDL flask data from Niwot Ridge show an increase in the annual atmospheric CO₂ mixing ratio from 323.1 parts per million (ppm) in 1968 to 356.8 ppm in 1992, or 1.40 ppm per year. Conway et al. (1994) reported a global growth rate of 1.43 ppm per year during 1981-92 for all NOAA/CMDL flask sampling sites.

Atmospheric CO₂ concentrations at Niwot Ridge show a seasonal pattern: the annual minimum occurs in August or September, and the annual buildup occurs in March-May. Conway et al. (1994) reported that the peak-to-peak seasonal amplitude for Niwot Ridge was 8.9 ppm during 1981-92.

Niwot Ridge, Colorado, U.S.A.
Alpine mountain
40°03' N, 105°38' W
3749 m above MSL

Niwot Ridge Graph

Monthly atmospheric CO₂ mixing ratios at Niwot Ridge.

Niwot Ridge Table

CO₂ mixing ratios at Niwot Ridge (ppm)

Access to Digital Data

Pacific Ocean Trends

References

Methods

CITE AS: Conway, T.J., P.P. Tans, and L.S. Waterman. 1994. Atmospheric CO₂ records from sites in the NOAA/CMDL air sampling network. In T.A. Boden, D.P. Kaiser, R.J. Sepanski, and F.W. Stoss (eds.), Trends '93: A Compendium of Data on Global Change. ORNL/CDIAC-65. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.

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Date revised 4/10/95 (gg)