The Effects of the Arctic Oscillation on Snow on Sea Ice in a Warming Arctic

Over the last four decades, Arctic sea ice has undergone unprecedented changes, becoming thinner, less extensive, and less resilient to summer melt. These changes have manifested in a seasonal ice cover that is more sensitive to its environmental conditions, including its overlying snow cover. Snow's insulating effect hinders the growth of sea ice in winter, while its reflective properties shield the ice surface and upper ocean from solar radiation in summer. Getting insight into the atmospheric drivers of the interannual and decadal variability of snow on sea ice is essential for improving our understanding of the seasonal evolution of the Arctic sea-ice cover.

In this work, we examine the role of the Arctic Oscillation (AO) in snow depth variability on sea ice over seasonal and multi-decadal timescales. A positive AO index enhances sea-ice export from the Arctic, which reduces the amount of time that sea ice can accumulate snow. However, a positive AO index also enhances Arctic snowfall, which increases the amount of snow that can accumulate. We investigate the competing effects of these two relationships on snow on Arctic sea ice using a combination of satellite, model, and reanalysis data over 1980-2021. We further investigate how the response of snow and sea-ice conditions to the AO has changed with sea-ice loss, which may reveal insight into the evolving relationship between climate variability and snow on sea ice in a warming climate.