Nitrogen oxide (NO and NOy) measurements were performed onboard an in-service aircraft within the\udframework of CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument\udContainer). A total of 330 flights were completed from May 2005 through April 2013 between\udFrankfurt/Germany and destination airports in Canada, the USA, Brazil, Venezuela, Chile, Argentina,\udColombia, South Africa, China, South Korea, Japan, India, Thailand, and the Philippines. Different regions\udshow differing NO and NOy mixing ratios. In the mid-latitudes, observed NOy and NO generally shows\udclear seasonal cycles in the upper troposphere with a maximum in summer and a minimum in winter.\udMean NOy mixing ratios vary between 1.36 nmol/mol in summer and 0.27 nmol/mol in winter. Mean NO\udmixing ratios range between 0.05 nmol/mol and 0.22 nmol/mol. Regions south of 40°N show no\udconsistent seasonal dependence. Based on CO observations, low, median and high CO air masses were\uddefined. According to this classification, more data was obtained in high CO air masses in the regions\udsouth of 40°N compared to the midlatitudes. This indicates that boundary layer emissions are more\udimportant in these regions. In general, NOy mixing ratios are highest when measured in high CO air\udmasses. This dataset is one of the most comprehensive NO and NOy dataset available today for the upper\udtroposphere and is therefore highly suitable for the validation of atmosphere-chemistry-models.
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