Atmospheric CO2 Data

Aircraft Campaign Data (1958-1961)

Atmospheric CO2 concentrations (ppm) derived from flask air samples taken aboard aircraft at 700, 500 and 300 hPa over North Pacific, Alaska, and Arctic Ocean from April 1958 through December 1961, spanning 11° 54' N to 86° 18' N latitude, and 105° 18' W to 166° 12' W longitude.

Measurement Frequency Data File Dates
CO2 intermittent flx_aircraft.csv 1958 - 1961

Supplemental Material

Documentation of steps to process legacy aircraft data (pdf)
C.D. Keeling 1968 Aircraft Project Report (pdf)
C.D. Keeling 1968 Aircraft Project Report Data Tables (pdf)
Raw Data Sets
Scan of original data set (Bollenbacher Brown Book) (pdf)
OCR of original data set and quality-checked CO2 data in I index (txt)
Fortran Program Routines and Input Files
qflcor08a_pub.f Fortran processing program that converts I index data values to final CO2 values, with text line numbers added for reference.
pecor.dat ascii file of period corrections used by qflcor08a_pub.f
SHPRES.DAT ascii file listing pressure of sample cell of NDIR analyzer indexed to sample sheet numbers (SHPRES = sheet pressure) used by qflcor08a_pub.f
qflcor08a_pub.job Unix script for executing program qflcor08a_pub.f
qflcor08a_pub-all.job Unix script for executing qflcor08a_pub.job for a specified aircraft flight.
checkdata.f Fortran program used to perform one of the data checks of fli.all data


Please cite as:

C. D. Keeling, T. B. Harris, and E. M. Wilkins, 1968. Concentration of atmospheric carbon dioxide at 500 and 700 millibars, Journ. Geophys. Research 73(14), 4511-4528.

Usage Restrictions

Scripps CO2 program data and graphics on are licensed under a CC BY license, Creative Commons Attribution 4.0 International License (, which clarifies appropriate uses and requirements, including that credit be given to the Scripps Institution of Oceanography at UC San Diego. Some products from this site incorporate data from sources external to the Scripps CO2 program, as indicated. Additional credit must be given for these products, as appropriate for that source.

Ethical usage may also require disclosing intentions at early stages to avoid duplicating ongoing studies at Scripps or elsewhere. For applications supporting peer-reviewed scientific publications, coauthorship may sometimes be appropriate. An example would be if an important result or conclusion depends on this product, such as the first account of a previously unreported phenomenon.

Please direct queries to Ralph Keeling (