An Estimation of Arctic Ocean Heat Convergence

The oceanic heat convergence within the Arctic Ocean, its variability and subsequent regional forcing of sea ice and atmosphere is of importance to the Arctic surface energy budget as well as to potential interactions of this region with midlatitude weather and climate via perturbations of the northern hemisphere atmospheric circulation. However, the observational estimates of the magnitude of this northward energy flux are not well constrained, due to both the spatial and temporal gaps in measurements at specific gates and their combined non-zero volume closure. This in turn presents a challenge to evaluating or tuning the respective fluxes in the global ocean and Earth system models, where the pan-Arctic volume budget is closed but over a wide range of volume and heat fluxes through individual Arctic-Subarctic gateways. We analyze results from a suite of regional and global models at varying spatial resolution to exemplify this problem and assess the sensitivity of and consequences to the local air-sea exchange via the surface turbulent heat fluxes related to the oceanic heat convergence. Our analysis reveals a relatively large range in magnitude of simulated oceanic volume and heat fluxes across the individual main gates, which subsequently control the amount of heat exchanged across the air-ice-ocean interface along the pathways of warm water into the Arctic Ocean. While understanding the impact and uncertainty in model estimates of the Arctic Ocean heat convergence on global climate variability is becoming a high priority, we emphasize the increasing need for continuous and improved observational estimates for constraining models.