NOTICE (August 2016): CDIAC as currently configured and hosted by ORNL will cease operations on September 30, 2017. Data will continue to be available through this portal until that time. Data transition plans are being developed with DOE to ensure preservation and availability beyond 2017.

image image image image

Atmospheric CO2 From Flask Air Samples at Barrow, Alaska, U.S.A.

graphics Graphics   data 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



Atmospheric CO2 samples were collected at monthly to semi-monthly intervals until 1981; after 1981 samples were collected at approximately weekly intervals. Samples are collected in 5-L evacuated glas 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.

Map showing location of Barrow, Alaska, U.S.A.

Barrow, Alaska, U.S.A.
On the coast of the Arctic Ocean
71°19' N, 156°36' W, 11 m above MSL


The average of unflagged data for the first full year of measurements (1974) was 332.8 ppmv; 2001 values averaged 371.8 ppmv for an upward trend of 1.44 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 PDF monthly averaged data.


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.