Annual measurements of atmospheric methane concentrations and isotopic ratios from Arrival Heights, Ross Island since November 1989

The atmospheric trace gas, methane (CH4), affects the radiative heat balance of the earth. The sources of atmospheric methane are not well understood. Large air samples (1000-1400 litres) of methane are collected from a compressor system at Arrival Heights annually (since 1989) and samples are analysed for methane concentrations, the isotopic ratios of 14C/ 13C and 13C/12C and the characteristics and fluxes of sources and sinks are assessed. Sample collection is aimed at the clean sector of the sky from the West through North to East, throughout the year. Measurements of methane carbon isotopes and its concentration in the atmosphere in Antarctica will help to determine the geographic variation, transport and the type and distribution of the sources of methane from the northern hemisphere.