Seasonally resolved chemical records of six ice cores from the Dronning Maud Land, Antarctica

The ammonium, calcium, and sodium concentrations from three intermediate depth ice cores drilled in the area of Dronning Maud Land, East Antarctica, have been investigated. Since all measurements were performed by a high-resolution Continuous Flow Analysis system, for the first time seasonal signals of chemical trace species could be obtained from the interior of central Antarctica over a period of approximately 2 millennia. Although the elevation as well as the accumulation rate differ between the drilling sites, similar values were obtained by comparing mean concentrations spanning the last 900 years. However, a distinct lack of intersite correlation was found on decadal timescales. Despite a noticeable accumulation change, apparent in one core, no significant concentration change of all three species has occurred. All the measured ions show clear seasonal signals over the whole records. While the sea-salt-related component sodium peaks simultaneously with calcium, the maximum ammonium concentration occurs in the snow with a time lag of 2 months after the sea-salt peak. More than 60% of the calcium concentration can be attributed to an ocean source. Elevated sodium concentrations were found within this millennium compared to mean values of the whole records, but the spatially varying shape of the increase suggests that a possible climatic signal is biased by local deposition effects.

对东南极洲毛德皇后地区域钻取的3根中等深度冰芯中的铵根、钙及钠离子浓度开展了研究。由于所有测量均采用高分辨率连续流分析（Continuous Flow Analysis）系统完成，本研究首次在约两千年的时间尺度上，从中南极内陆获取了化学示踪物种的季节变化信号。尽管各钻孔点位的海拔与积雪累积速率存在差异，但对比过去900年的平均浓度后，得到了相近的数值。然而在年代际时间尺度上，各点位间却表现出显著的相关性缺失。尽管其中一根冰芯呈现出较为显著的累积速率变化，但三种示踪物的浓度均未出现显著改变。所有被测离子在完整的记录序列中均表现出清晰的季节信号。与海盐相关的组分钠离子与钙离子同时达到浓度峰值，而铵根浓度的最大值则出现在海盐峰值后滞后两个月的积雪层中。超过60%的钙离子浓度可归因于海洋来源。相较于全序列的平均水平，本千年内的钠离子浓度出现升高，但该升高过程的空间分布差异表明，潜在的气候信号可能受到局地沉积效应的干扰。