Interannual variability of oceanographic conditions on the continental shelf outside of Sermilik Fjord

• Main Author: Glickman, Abbie A.
• Other Authors: Straneo, Fiamma
• Format: Bachelor Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: East Greenland; glacier; Greenland; Ice Sheet; North Atlantic; Sermilik
• Online Access: https://ir.library.oregonstate.edu/concern/undergraduate_thesis_or_projects/0r967b87d

Freshwater flux from the Greenland Ice Sheet has the capacity to affect regional and global circulation as well as contribute to sea level rise. Outlet glaciers are an important part of this process. They provide pathways for inland glaciers and ice sheets to melt and drain into the surrounding oceans. The Helheim Glacier, one of the largest outlet glaciers in East Greenland, is connected to the North Atlantic Ocean through the Sermilik Fjord. Warmer waters that penetrate the fjord can reach the glacier and contribute to melting, but the mechanism for this transport is not fully understood. In this thesis, we analyze mooring and summer conductivity, temperature, and depth (CTD) profiles from over a decade of research cruises. Our analysis focuses on the continental shelf adjacent to the fjord and broadens the current understanding of the variability of water masses entering and exiting the fjord. We found that the presence of the two main water masses, Polar Water (fresher and colder water) and Atlantic Water (higher salinity and warmer water), varied each year. The variation was most notable in the depth and extent of the two water masses, with Atlantic Water dominating the water column in some years and Polar Water in others. We also observed a consistent seasonal cycle for each year, with two minima of temperature and salinity, one concurrent maximum in temperature and salinity, and one isolated maximum of temperature. This behavior shows that despite the large daily variability in the region, there is still a consistent seasonal trend of temperature and salinity from one year to the next. The drivers of the seasonal cycle may be linked to the freshwater content over the shelf as well as the interannual variability observed in the water masses.