The original article does an excellent job of explaining how the heat from the Chuckchi gets buried below the surface layers in the Beaufort gyre.
The source of the increased halocline heat content can be understood by first considering how the BG halocline is ventilated. The northern Chukchi Sea (NCS) region exerts major influence on the interior structure of the halocline; here, water masses with the salinity range of the warm halocline outcrop at the surface (11). In this region, which we define to be within 70Ā°N to 75Ā°N and 150Ā°W to 170Ā°W, and south of the 300-m isobath (Fig. 2E), water is pumped down from the surface (via the Ekman transport convergence as a result of the prevailing anticyclonic wind stress gradients) and transported laterally by the BG geostrophic flow into the interior gyre (9, 11). Observations suggest that the NCS is characterized by the strongest time-mean Ekman downwelling in the entire Canada Basin, with downwelling rates averaging around 20 m yearā1, which corresponds to a vertical Ekman flux of around 0.05 Sv (1 Sv = 106 m3 sā1) for the region (12). This strong downwelling, associated with the region of maximum strength of the prevailing easterlies, takes place year-round with some interannual variability, but no significant trend over 2003ā2014 [see Figs. 4 to 6 in (12)].
Note that heat has been building up for decades and has expanded through the Beaufort gyre towards the CAA for many years. The heat is only slowly diffused back towards the surface water layer (according to the diffusion equation also known as the heat equation). However, the continental shelf margins have physical upwelling due to Ekman divergence. Heat may well back up at the continental shelf of the CAA. (This last issue is my interpretation, not in the paper.)
While vertical heat fluxes from the warm halocline are inhibited by the halocline stratification (that is, diapycnal diffusion is weak), reasonable estimates for heat lost vertically from the warm halocline may be obtained by considering the range of turbulent diffusivities estimated from observations in the central Canada Basin halocline: ~10ā7 to 10ā6 m2 sā1 (20). Heat loss is only considered across the top boundary of the layer. The range of diffusivities acting on the vertical temperature gradient centered around S = 31 (the top of the warm halocline) gives rise to upward heat fluxes in the range of 0.03 to 0.3 W mā2. Taking the heat content in the layer to be ~4 Ć 108 J mā2, these fluxes suggest a time scale for diffusive removal of the anomalous layer heat of between 40 and 400 years. Therefore, we cannot rule out that some fraction of the subducted summer heat is lost from the layer by vertical diffusion. Note that eddy fluxes may also be responsible for transporting heat laterally out of the BG region in a dynamical response to the wind-energy input (21).