This is accumulation data is derived from the Light weight In Situ Analysis (LISA) box at the EastGRIP ice coring site in Greenland in summer 2019, H2O2 is analysed by means of continuous flow analysis, but no standards were analysed for calibration and is thus represented as light counts in arbitrary units as described in Kaufmann et al., 2008; Röthlisberger et al., 2000. Conductivity is the electrical melt water conductivity as detected using a 3082 with micro flow cell 829 from Amber Science similarly to Bigler et al. 2011.