High resolution continuous flow analysis impurity data from the Mount Brown South ice core, East Antarctica

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 ∼ 30 cm ice equivalent throughout the length of the core (∼ 290 m), MBS represents a high resolution archive of ice core data spanning 1137 years (873–2008 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). 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 decadal average record. 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. The 1 mm averaged, 3 cm averaged, and MBS2023 decadal averaged datasets are available at the Australian Antarctic Data Center: https://doi.org/10.26179/9tke-0s16 (Harlan et al., 2024).