Abiotic radiocarbon simulated in NEMO ocean model

Following the Ocean Model Intercomparison Project (Orr et al., 1999, 2017), abiotic radiocarbon is simulated using the global ocean circulation model Nucleus for European Modelling of the Ocean (NEMO) version 3.6 (Madec, 2014), which is coupled to the Los Alamos sea-ice model (CICE, Rae et al., 2015). Simulation one, "Hist", was forced with inter-annually varying JRA-55-do atmospheric reanalysis data (version 1.5, Tsujino et al., 2018), which is available for the period 1958 through 2020 at 3-hour intervals, which is cycled over 1850 to 2020; and with historical atmospheric CO2 and ∆14C boundary conditions. The other simulation (”Hist-NYF”) was forced with the JRA-NY atmospheric data in every year, which is a one year chunk (01-May-1990 to 30-April-1991) from JRA-55-do (version 1.3) data when major climate modes such as the North Atlantic Oscillation, Southern Oscillation and Southern Annular Mode were largely neutral. The "Fix" simulation ran with fixed atmospheric CO2 and ∆14 C boundary conditions, using 1850 values and inter-annually varying JRA-55-do atmospheric reanalysis data.