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Why we observe?- New perspectives in ice melt dynamics through in-situ observation at the glacier ice-ocean interface

Why we observe?- New perspectives in ice melt dynamics through in-situ observation at the glacier ice-ocean interface

Monday, January 27, 2025 at 4:00 pm
Weniger 116
Jonathan Nash

Because glacier melt waters affect large-scale ocean circulation, projections of global climate and sea level rise are highly sensitive to details of melt physics at the ice-ocean boundary. In particular, the character and energetics of ocean flows adjacent to the submarine ice cliffs of marine terminating glaciers are poorly constrained because of the dangers calving imposes. In this talk I'll present observations that capture the spectrum of forcing that affects glacier ice melt (from millimeters to many-meters), and describe the underlying physics. These come from remotely-operated boats that image the shape of glaciers, measure the ocean properties, and can deploy other remotely operated vehicles that also deploy systems to sample physics at the near-vertical ice cliffs. The dataset includes boundary-layer measurements obtained using a platform we bolted directly to the submarine glacier face itself. We demonstrate that the melt process is influenced by a complex interplay between fjord currents, turbulent eddies, rising bubbles, falling sediment, and a complex 3D ice shape/structure. The complexity of these real ice-adjacent boundary-layer flows provides a new glimpse into the factors responsible for the large mismatch between parameterized and observed melt rates at temperate marine-terminating glaciers.

https://ceoas.oregonstate.edu/directory/jonathan-nash

Ethan Minot