A space-borne survey found that the icy lakes in Alaska's Arctic coastal plain is melting faster compared to 10 years ago.
Researchers from University of Waterloo, Ontario, Canada concluded that the Arctic lakes will melt earlier in the season and will have open water conditions for much longer. Two decades of satellite radar also showed that the bottom of the ocean will not freeze that much like what it used to be.
Using the radar data from Europe's ERS satellites, the researchers studied the progression of the freeze-up in an area near a Barrow starting 1990s. The Barrow, which is the largest settlement on Alaska's North Slope, includes over 400 lakes. Each lake has up to 60 square kilometers surface areas and about 1.5 meters deep, on the average.
Orbital radar is designed to detect presence of liquid water underground no matter how thick the covering is.
After analyzing the data, lead author Cristina Surdu and her colleagues found that the lakes have a tendency to go ice-free for approximately eight to 10 weeks during summertime. As autumn comes in, water will start to solidify again, but the portion of the lakes' ice that will remain solid until winter will be smaller.
In comparison with the data taken in 1991, the fraction of the grounded ice by April 2011 is down by 22 percent, which is almost close to a reduction of the thickness of ice by 18 to 22 centimeters.
They also found out that the decrease in sea ice after 2006 is relatively sharp.
"This is another piece in the puzzle of climate change in the region," Surdu said to BBC News.
"We're seeing warmer air temperatures; we're seeing sea-ice extent decreasing; and we're seeing a general greening of the Arctic with the treeline moving north. The lakes are part of that story."
This study was published in the Jan. 30 issue of The Cryosphere.
