Researchers track glacial meltwater with drifters
July 16, 2014
907-474-7208
7/15/2014
In an ice-choked fjord system in western Greenland, scientists have employed oceanographic equipment in a new way to collect fresh and detailed information about glacial meltwater near the ocean surface.
The project began with the research team trying to figure out how to get detailed measurements of the upper ocean in the Godthabsfjord in a non-disruptive way.
Previous studies in the area have only been able to record data from greater depths because equipment needed to be placed out of the reach of drifting icebergs.
Peter Winsor, associate professor of oceanography at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences, worked with Pacific Gyre Inc., a company specializing in drifter technology for ocean applications, and together came up with a design that could provide detailed measurements of the upper ocean and provide this data in real time via satellite.
The resulting drifters are durable enough to withstand collisions with the ice chunks relatively unscathed as they travel with the currents.
"Trying to measure the end result of accelerated melting of the Greenland Ice Sheet is a key problem in oceanography and glaciology," said Winsor, "but going out in a research vessel interferes with the very data you're attempting to collect."
Resembling bright orange basketballs floating among the ice blocks, several satellite-tracked surface drifters have been deployed over the last three years to gather measurements from the top 15 meters of the Godthabsfjord.
"This is the closest approach we can take, so far, to actually track the water mass," said Claudine Hauri, a chemical oceanographer at the UAF School of Fisheries and Ocean Sciences.
In addition to Winsor and Hauri, the research team consists of Martin Truffer of the UAF Geophysical Institute and Kunuk Lennert of the Greenland Climate Research Centre, the entity that funded the study.
The data supports new insights into the influence of Greenland Ice Sheet meltwater and its path through the fjord. All devices take measurements at the ocean surface and some are outfitted to collect additional data at seven and 15 meters deep as well.
The collected data is still being analyzed, but researchers are finding strong stratification near the glacier between cold and fresh meltwater in the upper meters and warmer, more saline water below.
The drifters have also revealed that a side fjord, the Uummannap Sulla, may play a more significant role in how the glacial melt is moving out to sea then previously thought. Four of 10 drifters traversed that route in their trek to the ocean rather than floating all the way to the Labrador Sea in the Godthabsfjord, which was thought to be the main route of glacial meltwater.
The research was featured in a recent issue of the American Geophysical Union journal EOS and the full article can be read online. In addition, an animation showing the tracks of all drifters deployed between August 2011 and October 2013 is posted on YouTube.
ADDITIONAL CONTACTS: Peter Winsor, 907-474-7740, pwinsor@alaska.edu, associate professor, UAF School of Fisheries and Ocean Sciences
Claudine Hauri, 907-474-7895, chauri@alaska.edu, research staff, UAF School of Fisheries and Ocean Sciences