Ice core data of Sodium (Na), Chlorine (Cl), and Acidity from 6 Greenland ice cores 1750-2012

Tropospheric reactive chlorine impacts the oxidation capacity of the atmosphere and may be influenced by anthropogenic activity, with potential implications for Northern Hemisphere ice core records of chlorine since the Industrial Revolution. Anthropogenic impacts on chlorine include direct emission of hydrochloride acid (HCl) from combustion, the mobilization of HCl from sea salt aerosol driven by atmospheric acidity, and heterogeneous chemistry converting sea salt chloride into reactive gaseous chlorine species (e.g., chlorine nitrite (ClNO2)). Here we present ice-core chlorine (Cl), sodium (Na), and acidity records from six Greenland ice cores (ACT_11d, Summit07, Summit10, Tunu, NEEM, NGT_B19). ACT_11d ice core was drilled in year 2011 at 66.5 ºNorth (N), 46.3 ºWest (W). Summit07 ice core was drilled in year 2007 at 72.6 ºN, 38.6 ºW. Summit10 ice core was drilled in year 2010 at 72.3 ºN, 38.3 ºW. Tunu ice core was drilled in year 2013 at 78.0 ºN, 33.9 ºW. NEEM ice core was drilled in year 2011 at 77.5 ºN, 51.1 ºW. NGT_B19 was drilled in year 1993 at 78.0 ºN, 36.4 ºW. Precise locations and other information are summarized in Ice Core Information.csv. Details on core extraction and dating are described in previous publications (Geng et al., 2014; Iizuka et al., 2018; McConnell et al., 2019; Opel et al., 2013; Spolaor et al., 2016). Ice core records are separated into two files: GreenlandIceCoreIonConcentration.csv contains ion concentration of Na and Cl, and calculated acidity (H+) for Summit07 ice core, GreenlandIceCoreElementalConcentration.csv contains elemental concentration of Na and Cl, and measured acidity for other Greenland ice cores.