Nitrate concentration and isotopes in DA2005 core from Dome A, East Antarctica

DA2005 core was recovered at a site about 300 m from the summit of Dome A, East Antarctica in 2004/2005. The total length of the core is 109.91m. The top 100.42m of the DA2005 core was analyzed in the Ice Core and Environment Chemistry Laboratory at South Dakota State University, USA for nitrate concentrations. Tubes 1 - 4 (0-1.765 m) were analyzed with discrete sampling followed by concentration determination by ion chromatograph. All other tubes were analyzed by CFA-IC (melter-based continuous flow analysis with ion chromatography detection). The top 100.42 m of the core corresponds to the last 2840years, from 840 BC to AD 1998. The top 8.98-86.66 m of the DA2005 core, covering the time period from 352 BC to AD 1838,were analyzed for nitrate isotopes in the stable isotope laboratory at University of Washington. Nitrate concentrations are shown in annual mean values. Negative year means BC.

DA2005 核心样本于2004/2005年从东南极洲的穹顶A峰约300米处成功恢复。该核心样本的总长度为109.91米。其中，核心顶部100.42米的样本在美国南达科他州立大学的冰芯与环境化学实验室进行了硝酸盐浓度的分析。前四管（1-4号，0-1.765米）采用离散取样，随后通过离子色谱法测定浓度。其余管材则采用基于熔融剂的连续流动分析（CFA-IC）进行检测。该核心顶部100.42米对应于过去2840年，即从公元前840年至公元1998年。核心顶部8.98-86.66米的样本，覆盖了从公元前352年至公元1838年的时间段，在美国华盛顿大学的不稳定同位素实验室进行了硝酸盐同位素的分析。硝酸盐浓度以年度平均值呈现。负年份表示公元前。