Bromine enrichment (Brenr) has been proposed as an ice core proxy for past sea-ice reconstruction. Understanding the processes that influence bromine preservation in the ice is crucial to achieve a reliable interpretation of ice core signals and to potentially relate them to past sea ice variability. Here, we present a 210 years bromine record that sheds light on the main processes controlling bromine preservation in the snow and ice at Dome C, East Antarctic plateau. Using observations alongside a modelling approach, we demonstrate that the bromine signal is preserved at Dome C and it is not affected by the strong variations in ultraviolet radiation reaching the Antarctic plateau due to the stratospheric ozone hole. Based on this, we investigate whether the Dome C Brenr record can be used as an effective tracer of past Antarctic sea ice. Due to the limited time window covered by satellite measurements and the low sea-ice variability observed during the last 30 years in East Antarctica, we cannot fully validate Brenr as an effective proxy for past sea-ice reconstructions at Dome C. In this database, annual averaged data for Br, Na and Brenr for the shallow ice core are provided.

This publication was generated in the frame of Beyond EPICA. The project has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement no. 815384 (Oldest Ice Core) and by the "Programma Nazionale per la Ricerca in Antartide" (PNRA, project no. PNRA16_00295). This study is also supported by the bilateral international exchange award Royal Society (UK)-CNR titled: Antarctic sea-ice history: developing robust ice core proxies (IEC/R2/202110), awarded to Rachael H. Rhodes and Andrea Spolaor.