This dataset contains hourly-averaged carbon dioxide dry air mole fractions measured during the year-long Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from October 2019 to September 2020. This is a merged dataset that combines cross-evaluated measurements performed in the University of Colorado (CU) and Swiss containers on Research Vessel Polarstern, along with cross-evaluated measurements performed on sea ice at Met City, and discrete whole air samples collected for post-cruise analysis at the National Oceanic and Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML). This merged dataset is recommended for further use by the community.The data columns include the Date and Time in Coordinated Universal Time (UTC), the latitude and longitude of the Research Vessel Polarstern, the carbon dioxide dry air mole fraction in µmol/mol, and the sampling location.

This merged dataset was created using the following datasets: Blomquist et al. (in review, a, b), Angot et al (in review), Dlugokencky et al. (2021).We used 1 sec time resolution positional data from the following datasets: PS122/1: Rex, M (2020), PS122/2: Haas, C (2020), PS122/3: Kanzow, T (2020), PS122/4: Rex, M (2021a), PS122/5: Rex, M (2021b)