On 10 April 2018, we provided updated processed data files with the ethane column removed. The ethane value was used only to provide a small correction to the methane isotopic ratio and was not of high enough quality to be used otherwise. Inclusion of this data column was confusing to the user. We also added data from January - February 2017 to the dataset. Furthermore, we updated the readme, use constraints, and abstract files for consistency and changed the title to exclude the time frame. We updated the headers in order to improve clarity. ---------------------------------------------- On 01 April 2021, we updated the readme to explain we converted the measured mole fraction from all files from traceable to the WMO X2007 scale (CO2) to WMO X2019 scale (CO2), following Hall et al. (2020) using the linear function: X2019=1.00079 * X2007 - 0.142 (ppm). Calibration tanks were also update to the new scale (CO2(ppm)_X2019) CITATION: Hall, B. D., Crotwell, A. M., Kitzis, D. R., Mefford, T., Miller, B. R., Schibig, M. F., & Tans, P. P. (2020). Revision of the WMO/GAW CO 2 calibration scale. Atmospheric Measurement Techniques Discussions, 1-33. DOI: https://doi.org/10.5194/amt-2020-408 On 09 April we added the target calibration tank South (CC339515 (NOAA)) to the calibration tanks list.