ArcticNet 2021 Annual Scientific Meeting Abstracts

There has been a recent focus on Greenlandic fjord oceanography as half of this island's contribution to sea level rise comes from submarine melting and ice discharge at tidewater glaciers. However, in the Canadian High Arctic, the role of fjords is not well understood, in part because of the lack of oceanic measurements. Two main oceanographic processes occur at the termini of tidewater glaciers during summer. The release of water produced by glacial meltwater runoff that finds its way to the bottom of the glacier is known as subglacial discharge, whereas submarine melting is the direct melting of the glacier by the ocean water. Quantifying subglacial discharge and submarine melting is critical to understanding fjord oceanography and cryospheric change in the catchment. This is typically done by comparing a temperatureconductivity-depth (CTD) profile close to the glacier with one that represents ambient oceanographic conditions farther offshore. Here, we develop a technique to depth-correct the ambient profiles to account for buoyancy difference following mixing with meltwater. Our results show that the standard method for comparing to ambient profiles may underestimate the amount of meltwater by up to 30%. We subsequently use eight years of water profiles taken in Milne Fiord, Nunavut (80.6N, 82.5W) to demonstrate the technique and investigate subglacial discharge and submarine melting in this fjord. The results show that both the amount of subglacial discharge and submarine melting meltwater are correlated to the amount of positive degree days (PDD).