Atmospheric carbon dioxide measurements in the Australian region: data from surface observatories

Abstract

Observations of the atmospheric carbon dioxide (CO₂) concentration made at surface locations in the Australian and Antarctic regions are presented for the period 19761984. These observations complement those already reported which were based on samples collected from aircraft throughout the troposphere and lower stratosphere in the same region. Data are presented for 4 sites, Cape Grim (40°41'S; 144°41'E). Mawson (67°37'S; 62°52'E), Macquarie Island (54°29'S; 158°58'E) and Wilbinga (31°25'S; 115°33'E) and for air samples collected on board ships traversing the Southern Ocean. By far the most comprehensive monitoring program described is that for the Cape Grim Observatory, where continuous in situ observations have been made since 1976. Methods are considered for the selection of data to represent the baseline or background concentration and a description is given of the natural variability of CO₂ concentration, including within-hour and diurnal variability, seasonal cycles, interannual and secular trends. The average rate of concentration increase over the period represented by the data was 1.5 ppmv yr^-1. A comparison is made between the selected data from these programs and similar data sets collected at Amsterdam Island and in New Zealand by other international projects. DOI: 10.1111/j.1600-0889.1987.tb00269.x