1137 years of high-resolution Continuous Flow Analysis impurity data from the Mount Brown South Ice Core

Abstract: The Mount Brown South ice core (MBS 69.111 S, 86.312 E) is a new, high resolution ice core drilled in coastal East Antarctica. With mean annual accumulation estimated to be 20-30 cm ice equivalent accumulation throughout the length of the core (~295 m), MBS represents a high resolution archive of ice core data spanning 1137 years (873 - 2009 CE), from an area previously underrepresented by high resolution ice core data. Here, we present a high-resolution dataset of chemistry and impurities obtained via continuous flow analysis (CFA), measured at the Physics of Ice, Climate, and Earth at the Niels Bohr Institute, University of Copenhagen. The dataset consists of meltwater electrolytic conductivity, sodium (Na+), ammonium (NH4+), hydrogen peroxide (H2O2), and insoluble microparticle measurements. The data are presented in three datasets: as a 1 mm depth resolution record, 3 cm averaged record, and decadally averaged record (based on the MBS2023 chronology). The 1 mm record represents an oversampling of the true resolution, as due to smoothing effects the actual resolution is closer to 3 cm for some species. Therefore, the 3 cm resolution dataset is considered to be the minimum true resolution given the system setup. We also describe the current Copenhagen CFA system, and provide a detailed assessment of data quality, precision, and functional resolution.A full description of the dataset is provided in Harlan et al., 2024 (in prep).Acknowledgements: We would like to acknowledge significant contributions from Paul Vallelonga. The authors would like to thank all participants in the 2018 and 2019 CFA campaigns, including, but not limited to Marius Simonsen, Alexander Zhuravlev, Mirjam Laderach, Nicholas Robles, Estelle Ngoumtsa, Michelle Shu-Ting Lee, Janani Venkatesh, Danielle Udy, Zurine Yoldi, Jia-mei Lin, Anna-Marie Klüssendorf, Andrew Moy, Andy Menking, Todd Sowers, Christo Buziert, Jesper Liisberg, and David Soestmeyer. The Mount Brown South ice core project is led by Tessa Vance, and would not be possible without the team of scientists, technicians, and ice core drillers, including Paul Vallelonga, Jason Roberts, Nerilie Abram, Meredith Nation, Chelsea Long and Alison Criscitiello.