Award: OCE-1536856

Award Title: Tracking Greenland Melt in the Ocean Using Noble Gas Fingerprints
Funding Source: NSF Division of Ocean Sciences (NSF OCE)
Program Manager: Baris M. Uz

Outcomes Report

Project Outcomes: Tracking Greenland Melt in the ocean using noble gas fingerprints The Greenland ice sheet is losing mass at a rate unpresented in recent centuries. As the ice sheet shrinks the amount of freshwater draining into the subpolar North Atlantic ocean increases. The rate and distribution of freshwater input is thought to influence ocean circulation on a wide range of scales, from coastal to global, creating a mechanism for Greenland ice sheet changes to feed back on ocean circulation and climate. Understanding the two-way links between changes in the ice sheet and ocean circulation is critical to accurate climate predictions. However, until recently, our ability to measure the amount of Greenland meltwater in the ocean has been poor, limiting our view of how it spreads and in understanding its impacts the regional ocean. The goal of this project has been to develop and deploy new tools to observe the concentrations of meltwater in the ocean around Greenland. Building on previous work tracing meltwater around Antarctica, we developed a method to use noble gases to measure meltwater concentrations in the ocean around Greenland. This method not only let us measure the amount of meltwater in the ocean, but also understand its origin: using the set of five noble gases we can differentiate meltwater that was created at the ice sheet surface due to warm air temperatures from submarine melting due to warm ocean waters. This allows us to look at two of the important controls on ice sheet mass loss. We used the method to observe meltwater spreading in number of fjords and coastal regions around Greenland (see figure 1). The project has resulted in the first quantitative ocean-based estimates of meltwater concentration and of meltwater flux out of major Greenlandic Fjords. It has allowed us to see the impact of buoyant meltwater on fjord waters, enabling a measurement of the upwelling of deep, warm, and nutrient rich fjord waters. We have also shown the depth distribution of meltwater flux out of Sermilik fjord. This clearly shows that Greenland?s meltwater does not enter the coastal ocean only at the surface, and suggests numerical models ought to take a more realistic depth distribution into account. Results from this project have been: published in 4 scientific papers, presented at many scientific meetings, used in numerous lectures and in summer courses, and presented to the public through a series of media pieces and outreach events. Last Modified: 02/23/2019 Submitted by: Nicholas L Beaird

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People

Principal Investigator: Albert J. Plueddemann (Woods Hole Oceanographic Institution)

Co-Principal Investigator: Fiammetta Straneo

Co-Principal Investigator: Nicholas L Beaird