Simulated ocean biogeochemistry and alkalinity addition experiments in Halifax harbor using a high-resolution nested Regional Ocean Modelling System (ROMS) (2016–2023)

This dataset contains model outputs from an implementation of the Regional Ocean Modelling System (ROMS) in a nested grid configuration with increasing spatial resolution from the Scotian Shelf to Halifax Harbour (coastal fjord, eastern Canada), a current test site for operational alkalinity addition. The biogeochemical model simulates oxygen dynamics, carbonate system processes (including air-sea gas exchange), and feedstock properties (dissolution, sinking). The first part of the dataset includes simulated time series at Station 2 (Scotian Shelf, 44.267°N/63.317°W) and at the compass buoy in the Bedford Basin (Halifax Harbour, 44.694°N/63.640°W) from multi-year hindcasts (2016-2023) with the coarsest (H1) and intermediate (H2) nested domains, respectively. Spatially resolved sea surface temperature in H1 is also included. The second part of the dataset provides model output for alkalinity addition experiments with 2 types of feedstock released at 3 locations inside and outside the Halifax Harbour. The dataset supports the analysis presented in Laurent et al. (2025) (https://doi.org/10.5194/egusphere-2025-3361). The circulation model is configured for the Halifax Harbour and surrounding areas using three nested domains with horizontal resolutions of 760 m (H1), 150 m (H2), and 50 m (H3), and 40 vertical layers. It is forced with ERA5 atmospheric data, boundary conditions from the GLORYS larger-scale ocean model and tides. The embedded biogeochemical model simulates the carbonate system, oxygen dynamics, and particulate/dissolved alkalinity feedstocks. Simulations include both multi-year hindcasts and a series of targeted alkalinity addition experiments with different feedstock types (dissolved and particulate) and release locations (Mill Cove, Tufts Cove, Herring Cove). Data are provided in NetCDF format and organized by grid resolution, location, and experiment type, showcasing: time series outputs at monitoring stations (Station 2 and Bedford Basin compass buoy); spatially resolved sea surface temperature fields; gridded air-sea gas fluxes (CO₂ and O₂) under control and experimental scenarios; and vertical profiles of biogeochemical tracers (e.g., oxygen, TIC, alkalinity). This resource supports regional marine carbon cycle modeling, coastal climate intervention and ocean alkalinity enhancement research.