Abstract
A unique dataset of marine atmospheric electric field observations over the Atlantic Ocean is described. The data are relevant not only for atmospheric electricity studies, but more generally for studies of the Earth's atmosphere and climate variability, as well as space-Earth interaction studies. In addition to the atmospheric electric field data, the dataset includes simultaneous measurements of other atmospheric variables, including gamma radiation, visibility, and solar radiation. These ancillary observations not only support interpretation and understanding of the atmospheric electric field data, but also are of interest in themselves. The entire framework from data collection to final derived datasets has been duly documented to ensure traceability and reproducibility of the whole data curation chain. All the data, from raw measurements to final datasets, are preserved in data repositories with a corresponding assigned DOI. Final datasets are available from the Figshare repository (https://figshare.com/projects/SAIL_Data/178500, ), and computational notebooks containing the code used at every step of the data curation chain are available from the Zenodo repository (https://zenodo.org/communities/sail, Project SAIL community, 2025).

Abstract
This study addresses the variability of gamma radiation measurements over the Atlantic Ocean. The analysis of back trajectories shows that the path of the air masses is the main factor determining gamma radiation levels over the ocean, rather than the distance to the coast. Different gamma values were recorded at different times in the same location as a result of the distinct origin of the corresponding air masses. Higher counts observed in the northeast Atlantic in winter compared with the spring values result from air masses coming from Europe and the African continent. In general, gamma radiation values over the ocean increase with increasing continental influence on the air mass above. A predictive classifica-tion model is developed showing that marine gamma observations can be used to classify marine boundary layer air masses according to the degree of continental influence.