Drivers of Local Ocean Heat Content Variability in ECCOv4

Abstract Variation in upper-ocean heat content is a critical factor understanding global climate variability. Using temperature anomaly budgets two-decade-long physically consistent ocean state estimate (ECCOv4r3; 1992–2015), we describe the balance between atmospheric forcing and transport mechanisms for different depth horizons at varying temporal spatial resolutions. Advection dominates tropics, while most relevant higher latitudes parts of subtropics, but dominant processes changes when integrating over greater depths considering longer time scales. While shown to increase with coarser resolution, overall budget it advection remarkably insensitive scale. A novel perspective on variability was made possible by combining unsupervised classification measure terms identify coherent dynamical regimes similar underlying mechanisms, which are prior research. The vast majority includes significant contributions both advection. However advection-driven regions were identified that coincide strong currents, such as western boundary Antarctic Circumpolar Current, forcing-driven defined shallower wintertime mixed layers weak velocity fields. This identification comprehensive sensitivity analysis exact resolution (for resolutions) should provide useful orientation future studies specific regions.