Δ¹⁴C and δ¹³C of DIC dataset from R/V Mirai and NABOS in the Arctic Ocean, with a synthesis of published records from 1979–2021

Abstract. We present a new full-water-column dataset of dissolved inorganic carbon (DIC) Δ¹⁴C, δ¹³C, DIC concentration, and CTD/chemical properties for the Arctic Ocean, obtained on R/V Mirai cruise transects (1999, 2000, 2002, 2006, 2008, 2009) and the 2008 NABOS expedition. In total, 255 new DIC Δ¹⁴C measurements (each with paired δ¹³C and DIC concentration) are reported here, of which 42 are from NABOS 2008. The archived dataset released with this study consists primarily of these unanalyzed data; raw numerical values from earlier published papers are not redistributed. To evaluate the long-term change of Arctic DIC Δ¹⁴C over 1979–2021 are used in the text for citation-based comparison and synthesis analysis. Older values transcribed or extracted from printed pages are treated as contextual information for surveying the time series and vertical structure, not as redistributed individual values. The primary aims of this paper are (i) to release the new Mirai/NABOS data in a long-term-archivable form, (ii) to organise the location, period, region, depth range and water-mass information of the published data, and (iii) by combining the new data with published records, to demonstrate the scientific utility of the full-water-column Arctic DIC Δ¹⁴C structure, including the surface mixed layer, the PWW/halocline, the AW layer and the deep water. The detailed interpretation of the temporal change of the AW layer and of Atlantification is deferred to a companion JGR-Oceans paper (Uchida et al., submitted).