Collaborative Research: Measuring the East Greenland Coastal Current on the Northeast Greenland Shelf

This project seeks to answer the question how much fresh (low salinity) water is carried from the Arctic Ocean along the East Greenland Coast into the North Atlantic Ocean and how much this transport may vary as more of the Greenland and Arctic ice sheets melt. For this purpose, an array of six moorings is to be deployed on the Northeast Greenland Shelf to make continuous measurements of temperature, salinity, and current velocities. An exciting new feature of this array includes a variable ballast buoy at the top of one of the moorings, the one closest to the coast, that allows measurements to be made all the way to the ocean surface when the region is ice free, but that prohibits collision of the instruments with sea-ice or icebergs in winter by keeping the mooring line below the ice then. The mooring observations are to be complemented by a modeling study that estimates how the East Greenland Coastal Current evolves over longer time scales. A collaboration with European partners who have a similar mooring array in deeper waters further offshore allows to examine the spatial extent of the current system. Together these efforts will fill a critical gap in our understanding of Arctic-Subarctic exchange, and results will be applicable to a range of scientific fields beyond physical oceanography including climate science, marine biogeochemistry, and fisheries management, among others. The oceanic circulation of the high-latitude North Atlantic is a critical component of our climate system and is potentially sensitive to the release of fresh, surface waters from the Greenland Ice Sheet and the Arctic Ocean. A large gap exists in our monitoring of this freshwater input on the Northeast Greenland Shelf (NEGS). This gap will be filled by measuring the southward-flowing East Greenland Coastal Current (EGCC) on the NEGS for the first time with continuous, direct measurements over an entire year. Based on existing data from summer shipboard sections and satellites, it is hypothesized that the freshwater transport in the EGCC is as strong as the freshwater transport of the better known East Greenland Current (EGC) further offshore at the shelf break. If true, the EGCC would be a major contributor to the total freshwater budget of the Arctic and a key player in Arctic-Subarctic exchange. In addition to the mooring array, it will be analyzed how these data fit into the larger scale NEGS circulation using model simulations, reanalysis products, and satellite data. The new ice-avoiding buoy technology that is to be developed as part of this project has the potential to be widely applicable to a range of environments and is significantly more cost-effective than other similar products. Results from this project will: (1) quantify the volume, heat, and freshwater transports of the EGCC on the NEGS, (2) compare these transports to those of the EGC measured by European partners, (3) identify the physical drivers of transport variability in the EGCC, and (4) assess the long-term variability of the EGCC and its role in the Arctic freshwater budget. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.