Data and code for "Humidity-Determined Distributions of Surface Oxygen"

This repository contains the datasets and source code associated with the manuscript "Humidity-Determined Distributions of Surface Oxygen." Contents MATLAB scripts to reproduce all figures from the manuscript (Fig2.m, Fig3.m, Fig4.m, Fig5.m, and Fig6.m) A global dataset of oxygen molar fraction values, derived from ERA5 monthly mean data (https://cds.climate.copernicus.eu/datasets/reanalysis-era5-single-levels-monthly-means?tab=download), covering the period 1940-2024 (mole_fraction_of_oxygen_in_air_1940-2024.nc). Data Processing Raw ERA5 data are not included in this repository due to their large size and their public availability through the Copernicus Climate Data Store (CDS). For Figure 2, the molar fractions within moist air as a function of the water vapor was obtained based on the assumption that oxygen conforms 20.946 ± 0.006%. Error bars reflect possible deviations of up to ±60 ppm in dry-air O₂ due to biological and oxidation processes. For Figures 3-4, oxigen molar fractions were calculated using the ensemble mean and ensemble spread products from hourly ERA5 data for the specific dates described in the manuscript. Figures 5-6 were generated using the reanalysis product type from the same hourly ERA5 dataset. Data for these figures were retrieved every 3 hours (00, 03, 06, 09, 12, 15, 18, and 21 UTC). Annual average for Figure 6 was calculated using Climate Data Operators (CDO) v2.0.5 and postprocessed with the MATLAB code provided in this repository. Finally, the global dataset was constructed with the same procedure but using ERA5 monthly means, with consistency verified against results from weighted statistics. Contact For further information, please contact: [e-mail]