Spatial scales of kinetic energy and its transfer across large-meso scales in the Arctic Ocean

Despite 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 research diagoses the kinetic energy (KE) and its transfer features of a rich-eddy Arctic Ocean from eddy-resolved sea-ice model FESOM (Finite-Element/volumE Sea ice-Ocean Model)  at about 1km in horizontal resolution, revealing the KE spectra at spatial scales and the seasonality. There are two peaks in the kinetic energy spectral density, one at the gyre scale of the Arctic boundary currents (centered at 1700-2000km), and the other associated with the mesoscale (centered at 60km), both of which exhibit a power-law scaling typical for large circulation and ocean eddies, respectively. Energy transfer diagnosis shows that there is inverse-cascade KE pathway at a hundred of kilometers to several killometers, of which the KE transfer value from larger scales to smaller scales is negative. The seasonality of the eddy KE spectrum and energy transfer in upper ocean is found to be highly consistent to sea ice loss trend, while eddy KE in deep ocean shows not significant seasonal variations.