Abstract

Robinson, Langhorne, Brett, Stevens, Rack, Stewart, Leonard, Williams, Grant, de Joux

The past decade has seen New Zealand-based researchers apply a variety of methods to considerably advance understanding of the Victoria Land Coastal Current (VLCC). The VLCC is a significant and consistent flow of supercooled Ice Shelf Water through Western McMurdo Sound, sourced from the ocean cavity beneath the Ross Ice Shelf. Here we summarise several ice-ocean processes, unique to supercooled water, which we have investigated over multiple field seasons. These include amplified boundary roughness generated by thick accumulations of platelet ice crystals, active quenching of supercooling along the flow path, and an active process of ice-ocean interaction that stabilizes the supercooling over tidal cycles. In quantifying these processes, it has been necessary to apply measurement protocols developed as a result of our repeated and sustained experience deploying instruments into significantly supercooled water. These protocols identify, mitigate against, and eliminate data corruption that can routinely occur when direct observations are made in water near, or below, the freezing temperature. The VLCC has thus provided an accessible natural laboratory to develop understanding and observational techniques that are likely to be relevant wherever supercooled Ice Shelf Water arises.