GSA Connects 2021 in Portland, Oregon

Paper No. 27-19
Presentation Time: 9:00 AM-1:00 PM


BRIGHAM-GRETTE, Julie1, GOLDNER, Mark2, MCKEON, Kelly3 and KIRSHEN, Alexander1, (1)Department of Geosciences, University of Massachusetts, Amherst, MA 01003, (2)Public Schools of Brookline, Health School, 100 Eliot Street, Brookline, MA 02467, (3)Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543

Warm oceanographic currents are contributing to ice melt from many parts of Greenland and Antarctica in large fjord and ice shelf systems that are difficult to access. Yet important knowledge of ice-ocean interactions and processes are needed to further our understanding of ice retreat rates and its impact on sea level trajectories into the future. Our field program, funded by the National Geographic Explorers Program, was focused exclusively on the glacial, sedimentologic, and oceanographic processes influencing the retreat of tidewater glaciers at the head of Kongsfjord, western Svalbard. Our work complements existing programs by collecting data concerning the daily changes in the activity of subglacial jets exiting the tidewater margin and its interaction with the water column oceanography and calving. The seasonal ice mélange at the ice face in these smaller systems is flushed out rapidly making it possible to work safely from small boats at a distance (between 200m to 4 km) from the calving ice face. The project follows on our earlier observations (with R. Powell, NIU) that warm North Atlantic water is impacting the ice face more today than seen in 2005, 2009, 2011 and 2014, contributing to increasing retreat rates. In contrast, warm Atlantic water had not yet reached the glacier face by the end of July in 2021 after a cold winter marked by the anomalous return of sea ice, suggesting a change in this year’s circulation. We observed different meltwater jets turning on and off on a daily to weekly basis using CTD casts, drone footage of plume activity and drogue casts to estimate overflow plume velocities. The science adds to observations of other aspects of the glacial system being monitored by Norsk Polar scientists, including the pending surge of Kongsvegen (Kohler et al.) and the subglacial release of an ice marginal lake being studied by Alexander et al, Univ of Oslo. The program was based out of the Kings Bay Research Station and logistically supported by the Norwegian Polar Institute’s Sverdrup Station, both in Ny Ålesund.