Insoluble dust, ammonium, calcium, conductivity, peroxide and acid measured in firn cores in Northern Greenland in 2015

Results from six firn cores obtained during a 426 km long northern Greenland traverse in 2015 between the NEEM and the EGRIP deep drilling stations situated on the Western and Eastern side of the Greenland ice sheet, respectively. The cores (9 to 14 m long) are analysed for chemical impurities by means of Continuous Flow Analysis (CFA); Insoluble dust, ammonium, calcium, acid, conductivity and peroxide. The data was dated by means of annual layer counting of mainly peroxide supplemented by calcium seasonal cycles and spans 18 to 53 years (±3 yrs) depending on local snow accumulation that decreases from west to east. Insoluble dust, ammonium, and calcium concentrations in the 6 firn cores overlap, and also the seasonal cycles are similar in timing and magnitude across sites, while peroxide (H2O2) and conductivity both have spatial variations. H2O2 is driven by the accumulation pattern and conductivity is likely influenced by sea salt. Data is published as part of Kjær et al. 2022, Climate of the past, https://doi.org/10.5194/cp-2021-99