Spatial Scales of Kinetic Energy in the Arctic Ocean

Abstract

AbstractDespite the importance of the Arctic Ocean for the large‐scale circulation and climate, there is still a knowledge gap in our understanding of the spatial characteristics of the Arctic Ocean circulation, especially for the mesoscale. This paper investigates the spatial characteristics of the Arctic Ocean circulation using a simulation with 1 km horizontal resolution. We revealed that there are two peaks in the kinetic energy (KE) spectral density at the 400 m depth, one at the gyre scale of the Arctic Circumpolar Boundary Current (centered at 1,700–2,000 km), and the other associated with the mesoscale (at about 60 km). However, at the 70 m depth, the boundary currents tend to mask the spectrum peak associated with the mesoscale. The KE spectrum exhibits a power‐law scaling typical for ocean eddies. We found that about 80% (50%) of the KE is on scales smaller than 100 km (30 km). The maximum KE content is in the 10–20 km scale band in most of the eddy‐rich regions of the abyssal ocean. The seasonality of the KE spectrum and KE content inside the Arctic Ocean follow the seasonality of eddy activity and baroclinicity, with low values in spring and maxima in late summer to autumn, and the seasonal variation is stronger at the 70 m depth than the 400 m depth. The strong concentration of KE on the very small spatial scales warrants future studies on energy transfer between scales in the Arctic Ocean.