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Atmospheric CO2 From Flask Air Samples at La Jolla Pier, California, 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



Replicate samples of atmospheric CO2 were collected at intervals of roughly one month, on average over the period of record, although sampling intervals have ranged from weekly to almost quarterly in a few early cases. The sampling has become more frequent and more regular in recent years. Samples are collected in 5-L evacuated glass flasks, and then returned to 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 La Jolla Pier, California, U.S.A.

La Jolla Pier, California, U.S.A.
32°9' N, 117°3' W
10 m above MSL


The first full year of complete, unflagged, data was from the continuous data record, 1973, so those data are used here as a baseline. The average CO2 concentration value during 1973 was 333.0 ppmv; 2001 values averaged 372.5 ppmv, for an upward trend of 1.52 ppmv/year. Graphics here show the first and last complete 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.