Arctic lakes' ice season is 24 days shorter than it was in the year 1950; new research suggests climate change has influenced the ice's thickness as well.
"We've found that the thickness of the ice has decreased tremendously in response to climate warming in the region," lead author Cristina Surdu a PhD student in University of Waterloo's Department of Geography and Environmental Management said in a news release. "When we saw the actual numbers we were shocked at how dramatic the change has been. It's basically more than a foot of ice by the end of winter, so it's very significant."
Researchers looked at about 400 Alaskan lakes and documented the ice changes over time. A research team looked at data from the European Space Agency (ESA) and found 62 percent of the lakes froze to the bottom in 1992; by 2011 only 26 percent of the lakes completely froze. That is a 22 percent reduction in "grounded ice" over the course of only 19 years.
Researchers can tell if a lake freezes to the bed by looking at the behavior of satellite radar signals. Radar signals are absorbed into the lakes' sediment if they are frozen to the bottom but when water exists under the ice the beam bounces back.
"Lakes that are completely frozen show up on satellite images as very dark while those that are not frozen to the lake bed are bright," the news release reported.
The team used the Canadian Lake Ice Model (CLIMo) to see if the lakes were frozen in years before 1991.
The model simulations showed the lakes melted 18 days earlier and froze six days later in the year 2011 than in 1950.
Changes in lake ice patterns can affect biological cycles such as algal growth; it can also interfere with transportation of goods across certain northern roads. Having less ice cover could also warm the local air.
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