Two decades of flask observations of atmospheric δ (O 2 ∕N 2 ), CO 2 , and APO at stations Lutjewad (the Netherlands) and Mace Head (Ireland), and 3 years from Halley station (Antarctica)

[摘要] We present 20-year flask sample records of atmospheric CO 2 , δ ( O 2 / N 2 ), and atmospheric potential oxygen (APO) from thestations Lutjewad (the Netherlands) and Mace Head (Ireland), and a 3-yearrecord from Halley station (Antarctica). We include details of ourcalibration procedures and the stability of our calibration scale over time,which we estimate to be 3 per meg over the 11 years of calibration, and ourcompatibility with the international Scripps O 2 scale. The measurementrecords from Lutjewad and Mace Head show similar long-term trends during theperiod 2002–2018 of 2.31  ±  0.07 ppm yr −1 for CO 2 and − 21.2  ±  0.8 per meg yr −1 for δ ( O 2 / N 2 ) at Lutjewad,and 2.22  ±  0.04 ppm yr −1 for CO 2 and − 21.3  ±  0.9 per meg yr −1 for δ ( O 2 / N 2 ) at Mace Head. They also show asimilar δ ( O 2 / N 2 ) seasonal cycle with an amplitude of 54  ±  4 per meg at Lutjewad and 61  ±  5 per meg at Mace Head, whilethe CO 2 seasonal amplitude at Lutjewad (16.8  ±  0.5 ppm) isslightly higher than that at Mace Head (14.8  ±  0.3 ppm). We show thatthe observed long-term trends and seasonal cycles are in good agreement withthe measurements from various other stations, especially the measurementsfrom the Weybourne Atmospheric Observatory (United Kingdom). However, there areremarkable differences in the progression of annual trends between the MaceHead and Lutjewad records for δ ( O 2 / N 2 ) and APO, whichmight in part be caused by sampling differences, but also by environmentaleffects, such as North Atlantic Ocean oxygen ventilation changes to whichMace Head is more sensitive. The Halley record shows clear trends andseasonality in δ ( O 2 / N 2 ) and APO, the latter agreeing especially well with continuous measurements at the same location made by theUniversity of East Anglia (UEA), while CO 2 and δ ( O 2 / N 2 )present slight disagreements, most likely caused by small leakages duringsampling. From our 2002–2018 records, we find a good agreement withGlobal Carbon Budget 2021 (Friedlingstein et al. (2021) for the global ocean carbon sink: 2.1  ±  0.8 PgC yr −1 , based on the Lutjewad record. The data presented in this work areavailable at https://doi.org/10.18160/qq7d-t060 (Nguyen et al.,2021).

[学科分类] 眼科学