Advanced Ocean Reanalysis of the Northwestern Atlantic: 1993-2022

Abstract: A 30-year high-resolution Northwestern Atlantic Ocean Reanalysis (NAOR) is presented. NAOR spans from January 1993 to December 2022 with a 4 km horizontal resolution and 50 vertical layers. It provides enhanced resolution and expands the spatial and temporal coverage of existing ocean reanalysis in the region. NAOR was conducted using the Regional Ocean Modeling System along with Ensemble Optimal Interpolation data assimilation. Open boundary and surface forcing conditions were obtained from GLORYS global ocean reanalysis and ECMWF ERA5 reanalysis. Multiple sources of satellite and in-situ observations were incorporated through the data assimilation. Additionally, major rivers were accounted for to include freshwater riverine discharge. NAOR was extensively evaluated against available independent observations. Spatio-temporal variations of mesoscale circulation, eddies, and boundary currents are well captured. Compared to GLORYS, NAOR offers a more accurate physical and dynamic baseline of the northwestern Atlantic Ocean, which can be utilized for a range of marine and environmental studies as well as climate impact research.