A high-precision continuous measurement system for the atmospheric O ₂/N₂ ratio at Ny-Ålesund, Svalbard and preliminary observational results

With the aim of carrying out detailed monitoring of temporal variations in the atmospheric O₂/N₂ ratio at Ny-Ålesund, Svalbard, we have developed a new highprecision continuous measurement system, with a precision of better than ‡ 4.0 per meg, using a fuel-cell O₂ analyzer. Considering the remoteness of the observation site, special attention was paid to the measurement system, in that: (1) the system can be controlled remotely from Japan using the Internet; (2) all of the data output from the system can be monitored and collected in Japan via the Internet; (3) a specially designed water trap based on a Stirling cooler is employed to automate the removal of water vapor from the sample air; (4) the CO₂ concentration can also be measured; and (5) it is possible to operate the system for one year without having to manually replace the high-pressure cylinders of standard gas and reference air. Systematic observation of the atmospheric O ₂/N₂ ratio using the newly developed measurement system began at the site on November 8, 2012. By analyzing the observational results obtained over the first month, the effectiveness of the measurement system was verified, and the causes of characteristic temporal variations in the observed atmospheric O₂/N₂ ratio were examined.