Atmospheric carbon dioxide (CO2) is measured continuously at Baring Head, providing the longest running record of this type in the Southern hemisphere. Observations at this station were started in the early 1970s and continue to the present.
Methane (CH4) is the second most important greenhouse gas after CO2 that is produced by human activities. While most of the anthropogenic emissions of CO2 are from industrial processes, most anthropogenic CH4 emissions are from agriculture.
Carbon monoxide (CO) plays a key role in atmospheric chemistry because it is the largest sink for hydroxyl radical (OH). OH is often called the 'detergent' of the atmosphere because it destroys many harmful pollutants.
There is a marked seasonal cycle in surface ozone (O3), with a maximum in winter and minimum in summer. There can also be significant variability from day to day caused by synoptic scale meteorological variations.