A 60-year atmospheric nitrate isotope record from a southeastern Greenland ice core with minimal postdepositional alteration

作者：Zhao Wei, Shohei Hattori, Asuka Tsuruta, Zhuang Jiang, Sakiko Ishino, Koji Fujita, Sumito Matoba, Lei Geng, Alexis Lamothe, Ryu Uemura, Naohiro Yoshida, Joël Savarino, Yoshinori Iizuka · 发表于：Atmospheric chemistry and physics · 年份：2025 · DOI：10.5194/acp-25-5727-2025 · 被引用次数：3 · 研究领域：Groundwater and Isotope Geochemistry、Atmospheric and Environmental Gas Dynamics、Isotope Analysis in Ecology

Abstract. Stable isotopes of atmospheric nitrate (NO3-) are valuable tools for tracing nitrogen sources and processes; however, their signals in ice core records are often disrupted by postdepositional processes. The ice core from the southeastern Dome (SE-Dome) in Greenland is a potential record of variations in atmospheric chemistry that has experienced a lower postdepositional effect owing to a high accumulation rate (∼1 m water equivalent per year). Herein, we report 60-year (1959–2014) δ15N(NO3-) and Δ17O(NO3-) records from the SE-Dome ice core. The δ15N(NO3-) decreased from 1960 to 1974 and exhibited clear seasonal changes (high in summer and low in winter). The Δ17O(NO3-) did not exhibit any significant long-term trends, but it did contain seasonal patterns. The mass-weighted annual average of δ15N(NO3-) values in the SE-Dome core were 4.2±2.8 ‰ lower than those in the Greenland Summit ice core between 1959 and 2006. The TRansfer of Atmospheric Nitrate Stable Isotopes To the Snow (TRANSITS) model under the SE-Dome condition estimated changes of only 0.9 ‰ for δ15N(NO3-) and −0.2 ‰ for Δ17O(NO3-) from the initial deposition. Although differences in the source of NO3- cannot be discounted, the lower δ15N(NO3-) values observed at SE-Dome compared to Summit were likely due to reduced postdepositional alteration. Therefore, the SE-Dome ice core NO3- record offers a precise reconstruction of nitrogen oxides (NOx) emissions from both North America and western Europe, as well ...