The interaction between ice and the ocean has significant implications for global sea level rise, freshwater flux, and the ocean’s meridional overturning circulation. Uncertainty in melt rates, particularly at ocean-terminating glaciers, is a major factor in projecting future sea level rise. Ocean-terminating glacier melt rates are challenging to determine due to the risks associated with working at actively calving glacier faces. Field measurements at Xeítl Sít in Alaska suggest that standard melt theories significantly underestimate observed melt rates, indicating a need for a better understanding of the underlying physics. Graduate students Nadia Cohen and Kaelan Weiss work as part of a larger project that aims to investigate these physics using novel measurement techniques.Nadia Cohen aims to quantify the roughness characteristics exhibited by submarine ice across varying length scales and to investigate any dependencies between surface roughness characteristics with larger-scale morphological features of the ice such as submarine ice slope.

A better understanding of submarine ice roughness characteristics may offer insight into the mechanics of submarine ice melt processes and together with identifying ice roughness dependence on larger-scale ice slope could be jointly used to improve submarine ice melt parameterizations.Kaelan Weiss is working to improve our understanding of the turbulent dynamics that govern melt rate at the near-vertical faces of glaciers and icebergs. Turbulent flow is present everywhere in the ocean, and the turbulence at ice-ocean interfaces control the amount of heat that flows from the ocean into the ice (and thus the melt rate). However, not all turbulence is created equal. At an ice-ocean interface, turbulence can be created through buoyant melt water or external flow dragging along the ice, each with different consequences for melt rate. To observe melt rate and boundary layer dynamics at glaciers and icebergs, we combine tried-and-true observational methods with novel techniques and robotic platforms which we design and build here at OSU. Through this work, we hope to understand the fundamental physics governing ice-ocean boundary layers so that we can improve our methods for predicting submarine melt rates of glaciers in regional and global ocean models.

Relevant publications:
Wengrove, M.E., Pettit, E.C., Nash, J.D., Jackson, R.H. and Skyllingstad, E.D., 2023. Melting of glacier ice enhanced by bursting air bubbles. Nature Geoscience16(10), pp.871-876.

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