258 / 2024-09-12 21:33:55

Arctic Storm Fingerprints on the Oceanic Mixed Layer beneath Sea Ice

Arctic Storms, Oceanic mixed layer, air-ice-sea interactions

Recent studies suggest that Arctic strom (cyclone or anti-cyclone) activity is becoming more frequent and intense in a warming climate (Zhang et al. 2023), significantly impacting sea ice dynamics through air-ice-sea interactions. While the effects of Arctic storms on oceanic changes have been discussed extensively, previous research has primarily focused on single case studies with limited oceanic resolution due to sparse observations or coarse model grids. This study leverages high-resolution oceanic simulations (eddy resolving at 1-km scale of FESOM2 simulations) to uncover the distinctive fingerprints of Arctic cyclones on the oceanic mixed layer, marked by a significant increase in enstrophy beneath fluctuating sea ice. Focusing on the eastern Eurasian Basin across the annual cycle, the study reveals that vertical mixing intensifies during Arctic cyclone passages, which coincides with surface sea ice melt, surface heat loss, and a deepened mixed layer. These effects persist for about three to six days, encompassing a full forcing-recovery period with alternating warm and cool spikes. Notably, Arctic Cyclone/anti-Cyclone significantly enrich oceanic turbulence or eddy activity from late summer through autumn, while their dynamical impacts at the subsurface are minimal from winter to spring due to the available potential energy (APE) deserts. These findings provide new insights into the interactions between Arctic storms and oceanic evolutions within the mixed layer beneath sea ice, highlighting their role in modulating upper ocean dynamics.