Sea ice drift and deformation in the coastal boundary zone

Abstract

Abstract Small‐scale sea ice deformation was studied in the coastal boundary zone (CBZ). Sequences of coastal radar images from the northern Baltic Sea (13 February to 13 May 2011) were used and trajectories of identifiable objects calculated. Average drift velocities in CBZ are small (<0.01 m/s), and events of high drift speeds are short and local. Deformations follow power law scaling but with an exponent of greater magnitude than in the Arctic. We discovered a connection between air temperature and sea ice deformation on a short time scale. During warm days, the mean deformation rate was significantly higher in all length scales than during cold days. This cannot be explained by changes in ice thickness or concentration, which suggests that the ice pack strength responds to air temperature faster than previously assumed. However, we cannot quantify how much this response is enhanced by lower ice thickness compared to the Arctic.