A 60-Year Sulfur Isotopic Record of Sulfate from a Southeastern Greenland Ice Core and Its Offset from Summit

Sulfate aerosols play an important role in Earth’s radiation balance by scattering solar radiation and modifying cloud albedo. Ice cores provide long-term archives of atmospheric sulfur, enabling reconstruction of its sources and transformations through isotopic analysis. Here, we present a 60-year (1955–2015) record of sulfur isotopic composition (δ 34 S) and non-sea-salt sulfate (nssSO 4 2– ) flux from the SE-Dome ice core in southeastern Greenland. The δ 34 S-nssSO 4 2– record shows low values (∼2‰) before 1970 and an increase to ∼5.5‰ around 2000, broadly consistent with changes in anthropogenic SO 2 emissions. However, the post-2000 decrease in δ 34 S indicates additional influences beyond anthropogenic trends. Comparison with published δ 34 S records from the Summit ice core reveals a similar temporal evolution but a persistent ∼2‰ offset, with systematically higher values at Summit. We attribute this offset to differences in air-mass origin, snowfall seasonality, and volcanic influence between the two sites. Our results highlight the importance of spatial variability and site representativeness in interpreting ice core sulfur isotope records of Arctic sulfate aerosols.