Tritium and Helium Isotope Data (1987–2013) for the Atlantic Layer of the Arctic Ocean

This dataset supports the study titled \"Multi-Decade Tracer Study of the Circulation and Spreading Rates of Atlantic Water in the Arctic Ocean\" (JGR: Oceans, 2024, in press) and complies with the Open Research Data Availability Statement. It consolidates tritium and helium isotope data collected during 21 Arctic Ocean expeditions over 27 years. While subsets of these data have been previously published as isotope concentrations or ^3H-^3He ages (e.g., Bönisch & Schlosser, 1995; Ekwurzel, 1998; Ekwurzel et al., 2001; Schlosser et al., 1995, 1999; Smethie et al., 2000; Mauldin et al., 2010), this is the first complete compilation.
Samples from the ARK-IV/3, ARK-IX/4, ARK-XI/1, and ARK-XII cruises were analyzed at the University of Heidelberg's Institute for Environmental Physics (IUP) using methodologies described by Bayer et al. (1989). All remaining samples were processed at the Lamont-Doherty Earth Observatory (LDEO) Noble Gas Laboratory, following the procedures of Ludin et al. (1998). Inter-laboratory calibration ensures consistency, with analytical uncertainties for ^3H and helium isotope measurements within expected error ranges. Charles “Chuck” McNally performed the majority of gas extractions at LDEO, while tritium and helium isotope measurements were conducted by Ralf Weppernig, Gerhard Bönisch, Brent Turrin, Ronny Friedrich, and Tobias “Toby” Koffman.