The interaction of solar radiation with young ice (Invited)

In recent years there has been a significant increase in the amount of seasonal sea ice in the Arctic leading to more open water and young ice. Young ice and open water are windows to the ocean allowing significant amounts of solar radiation to penetrate, affecting the heat budget, biological activity, and chemical processes. In early spring the impact of young ice is considerable, since there is ample incident solar radiation and biological and photochemical activities are beginning after winter’s darkness. As young ice develops, frost flowers form and snow accumulates. Associated with these physical changes are changes in the partitioning of solar radiation by the ice. For example, there is a rapid increase in albedo from 0.1 to 0.8 as thin ice becomes covered by snow. Light transmission through thin ice is also sensitive to the presence of frost flowers or a snow cover. Transmittances for thin (0.1 to 0.3 m) ice can decrease by more than an order of magnitude once the ice becomes snow-covered. In late spring, thin ice melts quickly due to solar heating. The resulting open water absorbs over 90% of the incident solar radiation enhancing lateral and bottom melting of nearby ice.