Monthly atmospheric CO2 record from Cape Grim, Tasmania, Australia

Graphics Digital Data

Pieter P. Tans and Thomas J. Conway

NOAA Climate Monitoring and Diagnostics Laboratory, Boulder, Colorado 80305, U.S.A.

Period of Record


Cape Grim, Tasmania, Australia
Promontory seashore
40°68' S, 144°68' E
94 m above MSL


The sampling site at Cape Grim, Tasmania, is operated in cooperation with the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Division of Atmospheric Research. Cape Grim replaced Kaitorete Spit, New Zealand, in the NOAA/CMDL network after it was established that Cape Grim was a more suitable site for representative measurements at that latitude (Conway et al. 1988). From the outset of this cooperative program, samples have been taken in 0.5-L flasks. However, two sampling procedures have been used. One of the procedures is followed at all of the NOAA/CMDL flask sampling sites, as detailed in Komhyr et al. (1985a) and Conway et al. (1988). In the second procedure, the air samples are dried by passage through a glass column packed with anhydrous, granular magnesium perchlorate, as detailed in CSIRO (1989). From 1985 to 2002, annual average mixing ratios of CO2 at Cape Grim, calculated on the basis of undried air samples, rose from 343.51 parts per million (ppm) in 1985 to 379.65 ppm in 2002.

CITE AS: Tans, Pieter P. and T.J. Conway, 2005. Monthly Atmospheric CO2 Mixing Ratios from the NOAA CMDL Carbon Cycle Cooperative Global Air Sampling Network, 1968-2002. 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, Tenn., U.S.A.

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