Ice Types and Processes in the Advancing Chukchi Sea Ice Edge from Visual Observations and Digital Photos

Ice types were identified from the Sikuliaq while underway during the ONR SeaState cruise into the Chukchi Sea ice edge in Oct 2015 and were recorded in the ASSIST system for ice observations at 5 to 10km intervals while an automatic ice camera provided a continuous swath of photography between observations. Several transects of the newly advancing ice edge were conducted. From these observations, at much higher resolution than available from satellite imagery, sub meter scale ice features can be identified. This high resolution allows differentiation for example, between new pancake ice formed in wave fields and smooth nilas ice that forms in the absence of waves. The presence or absence of remnant ice floes from the summer decay period can also be identified. From these transects we differentiate between the role that old remnant floes may or may not play in stabilizing the ice edge during the advance of the ice cover, whether waves generated outside the ice edge can form pancake ice at the edge as found in the Antarctic, or whether neither waves nor remnant ice are needed and the ice edge advances by quiet ice growth, driven primarily by thermal processes. Ice growth processes may also vary with location and timing, and dependencies on variations in ocean and atmospheric forcing will be identified.