Study of Greenland Glacier Flow Rates Highlights Environmental Effects
While the term ‘glacial’ often refers to very slow and steady movement, recent research has shown that glaciers can actually speed up and slow down rapidly—sometimes within hours—due to changing weather conditions such as air temperature, rainfall, and tidal fluctuations.
A group of researchers, featuring scientists from Hokkaido University in Japan, closely examined the activity of a Greenland glacier over six summer seasons. They analyzed how local weather and tidal patterns affected the glacier’s movement, with their findings published in the journal The Cryosphere.
Lead author Shin Sugiyama from Hokkaido University noted, “Understanding short-term changes in speed is essential for uncovering the physical mechanisms that drive glacier movement. However, there is a lack of research regarding Greenland’s tidewater glaciers, especially in areas close to the calving front. Investigating glacier dynamics near the ocean is vital for comprehending current and future ice sheet mass loss.”
The research focused on Bowdoin Glacier (known as Kangerluarsuup Sermia in Greenlandic), whose front releases ice into Bowdoin Fjord located in northwestern Greenland. This glacier, like many others, has been shrinking and thinning rapidly since 2008.
To gather data, the team installed GPS units at various points along the ice from 500 meters to four kilometers from the calving front. They also set up sensors to monitor air temperature and rainfall near the glacier, collecting a comprehensive dataset over 90 days from 2013 to 2019.
The findings disclosed that the glacier’s flow rate increased on a daily basis, with two distinct spikes observed each day. The first spike can be attributed to the rise in meltwater generated during warmer daytime temperatures. The second increase was primarily noticeable near the glacier’s terminus, likely influenced by the tidal movements, with peak speeds occurring around low tide.
Additionally, the glacier exhibited one or two notable acceleration events each year, typically coinciding with either abnormally high temperatures or significant rainfall.
Sugiyama commented, “The relationship between ice speed and temperature highlights how meltwater production greatly affects the behavior of Greenland’s outlet glaciers.” The flow of the glacier intensified when temperatures exceeded 10 degrees Celsius, with only a two-hour delay between peak temperatures and peak speeds, demonstrating how swiftly meltwater reaches the glacier’s base.
However, the connection between intense rainfall and glacier speed was more intricate, as the researchers speculated this resulted from the interaction of tidal effects with the efficiency of drainage beneath the glacier.
Sugiyama concluded, “Our findings offer crucial insights into the dynamics of tidewater glaciers and enhance our understanding of how the Greenland ice sheet might evolve in a changing climate and environmental conditions.”
