NOAA/CMDL Atmospheric CO2 Records from Continuous Monitoring

The Air Resources Laboratories of the National Oceanic and Atmospheric Administration (NOAA) established four baseline monitoring stations in the mid-1970s to conduct continuous measurements of atmospheric CO2 mixing ratios. The stations are operated by NOAA's Climate Monitoring and Diagnostics Laboratory (CMDL). The four sites are located at Point Barrow, Alaska; Cape Matatula, Samoa; Mauna Loa Observatory, Hawaii; and South Pole Station, Antarctica. Methodologies and instrumentation at the four sites are similar, with minor modifications made to accommodate the local environment. Detailed descriptions of the methods used at the Mauna Loa Observatory are in Komhyr et al. (1989). This description, for the most part, also pertains to the other three sites. Additional information can be found in Peterson et al. (1986) for Barrow, Gilette et al. (1987) for the South Pole, and Waterman et al. (1989) for American Samoa. The summary of the measurement method that follows is for all four sites. Differences and important hardware information is given for each site.