Short-term Impacts of Arctic Summer Cyclones on Sea-ice in the Marginal Ice Zone

Abstract:

We use the ERA‐5 reanalysis to statistically analyze how surface energy fluxes and wind forcing from Arctic cyclones in the marginal ice zone between May and August (1999–2018) locally affect sea ice extent on 1–10 day time scales. In May and June, cyclones decelerate the local seasonal loss of sea ice extent compared to when no cyclone is present, which we find is due to cyclone cloud cover reducing net shortwave radiative fluxes at the surface. By July and August, cyclones no longer decelerate the seasonal loss of sea ice extent, despite still reducing the net surface energy flux. Surface wind forcing across the ice edge only explains up to 13.5% of the variance in local sea ice extent in late summer, suggesting that processes other than wind‐induced drift and atmospheric energy fluxes drive late‐summer sea ice extent variability. This result emphasizes the need for fully coupled models and ice mass balance observations within the marginal ice zone for understanding how cyclones affect both the atmospheric and oceanic forcings that determine the evolution of sea-ice cover on synoptic timescales.