What Causes Anthropogenic Ocean Warming to Emerge from Internal Variability in a Coupled Model?

Abstract In response to increasing human emissions, the global ocean is continually warming. The spatial distribution of this warming can result from several mechanisms, difficult disentangle in observations. Idealized modeling studies have successfully separated contribution additional heat passively entering changing circulation redistributing pre-existing perturbations air–sea fluxes. However, time scales these different contributions been largely unexplored so far. Here, we revisit decomposition with a novel numerical framework investigate mechanisms driving regional and its emergence internal variability. Based on IPSL-CM6A-LR coupled model large ensemble transient climate change simulations, extract both fluctuations externally forced signal each component surface With stand-alone configuration ocean, then test applied all fluxes together or individually. We find that processes vary time, reinforcing counteracting other, causing subsurface temperature changes be advanced delayed. Anthropogenic upper water masses generally driven by uptake excess stored circulation. Circulation minor role at when signals emerge. On contrary, deeper are much more sensitive forcings play an important setting warming, through redistributive cooling.