Abstract. The Antarctic ice sheet’s future contribution to sea level rise is difficult to predict, mostly because of the uncertainty and variability of the surface mass balance (SMB). Ice cores are used to locally (km scale) reconstruct SMB with a very good temporal resolution (up to sub-annual), especially in coastal areas where accumulation rates are high. The number of ice cores records has been increasing these last years, revealing an important spatial variability and different trends of SMB, highlighting the crucial need for greater spatial and temporal representativeness. We present records of density, water stable isotopes (δ¹⁸O, δD and deuterium excess), ions concentrations (Na⁺, K⁺, Mg⁺, Ca⁺, MSA, Cl^-, SO₄^2- and NO₃^-), and continuous electrical conductivity measurement (ECM), as well as age models and resulting surface mass balance from the top 120 m of two ice cores (FK17 and TIR18) drilled on two adjacent ice rises located in coastal Dronning Maud Land and dating back to the end of the 18^th century. Both environmental proxies and derived data show contrasting behaviors, suggesting strong spatial and temporal variability at the regional scale. In terms of precipitation proxies, both ice cores show a long-term decrease of deuterium excess (d-excess) and a long-term increase of δ¹⁸O, although less pronounced. In terms of chemical proxies, the non-sea-salt sulfate (nssSO₄^2-) concentrations of FK17 are twice the ones of TIR18 and display an increasing trend on the long-term while there is only a small increase after 1950 in TIR18. The SO₄^2- / Na⁺ ratios show a similar contrast between FK17 and TIR18 and are consistently higher than the sea water ratio, indicating a dominant impact of the nssSO₄^2- on the SO₄^2- signature. The mean long-term SMB is similar for FK17 and TIR18 (0.57 and 0.56 m i.e. a^-1 respectively), but the annual records are very different: since the 1950’s, TIR18 shows a continuous decrease while FK17 has shown an increasing trend until 1995 followed by a recent decrease. The datasets presented here offer numerous development possibilities for the interpretation of the different paleo profiles and for addressing the mechanisms behind the spatial and temporal variability observed at the regional scale (tens of km scale) in East Antarctica. The “Mass2Ant IceCores” datasets are available on Zenodo (https://doi.org/10.5281/zenodo.7848435; Wauthy et al., 2023).

中文翻译：

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Dronning Maud Land（南极洲东部）两个冰芯顶部 120 米的物理化学特性：环境指标时空区域变异性的打开窗口

摘要。南极冰盖未来对海平面上升的贡献很难预测，主要是因为表面质量平衡 (SMB) 的不确定性和可变性。冰芯用于局部（公里尺度）以非常好的时间分辨率（高达亚年度）重建 SMB，特别是在积累率高的沿海地区。近年来冰芯记录的数量一直在增加，揭示了重要的空间变异性和 SMB 的不同趋势，突出了对更大空间和时间代表性的迫切需求。我们提供密度记录、水稳定同位素（δ ¹⁸ O、δD 和过量氘）、离子浓度（Na ⁺、K ⁺、Mg ⁺、Ca ⁺, MSA, Cl ^- , SO ₄ ^2-和 NO ₃ ^- ), 和连续电导率测量 (ECM), 以及年龄模型和从两个冰芯 (FK17 和 TIR18) 顶部 120 米钻探的表面质量平衡在位于沿海 Dronning Maud Land 的两个相邻的冰山上，其历史可以追溯到 18^世纪末。环境指标和派生数据都显示出截然不同的行为，表明区域范围内存在强烈的空间和时间变异性。^{就降水代理而言，两个冰芯均显示出氘过量（d-过量）的长期减少和 δ 18} O的长期增加，尽管不太明显。在化学代理方面，非海盐硫酸盐（nssSO₄ ^2- ) FK17的浓度是TIR18的两倍，长期呈上升趋势，而TIR18在1950年以后只有小幅上升。SO ₄ ^2- / Na ⁺比率在 FK17 和 TIR18 之间显示出相似的对比，并且始终高于海水比率，表明 nssSO ₄ ^2-对 SO ₄ ^2-特征的主要影响。FK17 和 TIR18 的平均长期 SMB 相似（0.57 和 0.56 m，即^-1分别），但年度记录却大不相同：自 1950 年代以来，TIR18 呈持续下降趋势，而 FK17 呈上升趋势，直到 1995 年才出现下降趋势。此处提供的数据集为解释不同的古剖面和解决在东南极洲区域尺度（几十公里尺度）观察到的空间和时间变异性背后的机制提供了许多发展可能性。“Mass2Ant IceCores”数据集可在 Zenodo 上获得（https://doi.org/10.5281/zenodo.7848435；Wauthy 等人，2023 年）。