Title: Review of "Gas enclosure in polar firn follows universal law"
Abstract: Schaller et al. present a new, extensive and highly valuable dataset on the bubble close-off process in polar firn, obtained using x-ray computed tomography.I would like to congratulate the authors on this achievement, which must have taken considerable time and analytical effort.The authors use this data set to provide strong observational evidence that bubble closure happens at a single porosity value, independent of the climatic conditions at the site.Detailed observations of the close-off process are the only way to make progress on this complex problem, and I am very enthusiastic about this effort.The main experimental observation, namely that sealing of layers occurs at a constant density/porosity