Sea Surface Temperature Variability on the SE‐Greenland Shelf (1796–2013 CE) and Its Influence on Thrym Glacier in Nørre Skjoldungesund. Issue 3 (2nd March 2020)

• Record Type: Journal Article
• Authors: Wangner, David J.; Sicre, Marie‐Alexandrine; Kjeldsen, Kristian K.; Jaeger, John M.; Bjørk, Anders A.; Vermassen, Flor; Sha, Longbin; Kjær, Kurt H.; Klein, Vincent; Andresen, Camilla S.
• Is Part Of: Paleoceanography and paleoclimatology. Volume 35:Issue 3(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-02
• Subjects: Greenland -- Alkenones -- Ice‐rafted debris -- Paleoceanography -- Sea surface temperature -- Fjord; Paleoceanography -- Periodicals; Paleoclimatology -- Periodicals; 551.46
• DOI: 10.1029/2019PA003692
• Languages: English
• ISSNs: 2572-4517

Abstract

Abstract: Heat transport via ocean currents can affect the melting of marine‐terminating glaciers in Greenland. Studying past changes of marine‐terminating glaciers allows assessing the regional sensitivity of the Greenland Ice Sheet to ocean temperature changes in the context of a warming ocean. Here, we present a high‐resolution multiproxy marine sediment core study from Skjoldungen Fjord, close to the marine‐terminating Thrym Glacier. Grain‐size data are obtained to reconstruct the calving activity of Thrym Glacier; sortable silt is used as a proxy for fjord water circulation, and sea surface temperatures (SSTs) are reconstructed from alkenone paleothermometry (Uk'37). Measurements of 210 Pb, 137 Cs, and 14 C indicate that the core covers the past 220 years (1796–2013 CE). Comparisons with modeled SST data (Hadley Centre Sea Ice and SST) and instrumental temperatures (International Council for the Exploration of the Sea) suggest that the SST proxy record reflects temperature variability of the surface waters over the shelf and that alkenones are advected into the fjord. Additionally, average temperatures and the amplitude of fluctuations are influenced by alkenones advected from upstream the Irminger Current. We find that the SST record compares well with other alkenone‐based reconstructions from SE‐Greenland and thus features regional shelf water variability. The calving activity as well as the terminus position of Thrym Glacier did not seem to respond to the SST variability. Limited ice‐ocean interactions owing to the specific setting of the glacier would explain this. Instead, the fjord circulation may have been influenced by enhanced meltwater production as well as to larger scale changes in the Atlantic Meridional Overturning Circulation. Key Points: Alkenone‐based sea surface temperature reconstructions reveal common SE‐Greenland shelf variability during the 20th century Increasing ocean temperature did not result in a retreat of Thrym Glacier Sortable silt parameters indicate that fjord water column flow is influenced by increased meltwater release and/or shelf water circulation