Long-term continuous atmospheric CO 2 measurements at Baring Head, New Zealand

• Published in: Atmospheric Measurement Techniques
• Main Authors: S. E. Nichol, K. Riedel, S. E. Mikaloff Fletcher, A. J. Gomez, B. B. Stephens, G. W. Brailsford, M. R. Manning
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2012
• Subjects: Environmental engineering; TA170-171; Earthwork. Foundations; TA715-787; Southern Ocean; New Zealand; Scripps
• Online Access: https://doi.org/10.5194/amt-5-3109-2012; https://doaj.org/article/54b335a1cb4f46d49ef0e905f696d38a

We present descriptions of the in situ instrumentation, calibration procedures, intercomparison efforts, and data filtering methods used in a 39-yr record of continuous atmospheric carbon dioxide (CO 2 ) observations made at Baring Head, New Zealand. Located on the southern coast of the North Island, Baring Head is exposed to extended periods of strong air flow from the south with minimal terrestrial influence resulting in low CO 2 variability. The site is therefore well suited for sampling air masses that are representative of the Southern Ocean region. Instrumental precision is better than 0.015 ppm (1-σ) on 1-Hz values. Comparisons to over 600 co-located flask samples, as well as laboratory based flask and cylinder comparison exercises, suggest that over recent decades compatibility with respect to the Scripps Institution of Oceanography (SIO) and World Meteorological Organisation (WMO) CO 2 scales has been 0.3 ppm or better.