Abstract

Storms can have a direct impact on sea ice, but whether their effect is seen weeks to months later has received little attention. The immediate and longer term impacts of an idealized open water wind storm are investigated with a one-dimensional coupled ice-ocean model. Storms with different momentum, duration and date of occurrence are tested. During the storm, the mechanical forcing causes a deepening of the mixed layer, leading to an increase in mixed layer heat content, despite a decrease in mixed layer temperature. This results in a delay in sea ice formation that ranges between a few hours to weeks compared to the control run, depending on the storm characteristics. Throughout the freezing period, the storm-induced thick mixed layer experiences little variability, preventing warm water entrainment at the base of the mixed layer. This leads to faster sea ice growth compared to the control run, resulting in sea ice thickness differences of a few millimeters to around 10 cm before the melting onset. These results are stronger for runs with higher momentum storms which cause greater mixed layer deepening. Storms occurring in early August, when the ocean surface heat flux is positive, also amplify the results by forcing a greater increase in mixed layer heat content. The impacts of the storms are sensitive to the initial stratification, and amplified for a highly stratified ocean. We suggest that localized storms could significantly influence the seasonal dynamics of the mixed layer and consequently impact sea ice conditions.