Researchers say Lake Superior water temperature on the rise

DULUTH, Minn. — A warmer Lake Superior could improve the chances of catching salmon and other species as well as provide benefits for the Great Lakes shipping industry.

MPR News reported that the average surface water temperature for the entire lake hit 68.5 degrees Fahrenheit.

University of Minnesota-Duluth researchers have found that summer surface temperatures in Lake Superior have increased by 5 degrees over the past 30 years.

Jay Austin, a physicist with the Large Lakes Observatory at UMD, attributes the rapid change to the connection between the amount of ice on the lake the previous winter, and how warm the lake gets the following summer. Less ice translates to warmer summer waters.

And it’s in the winter that Minnesotans are really feeling the effects of climate change, Austin said. The average winter temperature in the state has risen by about 1 degree per decade since the 1970s.

“The difference between one of those low-ice and high-ice years can be due to as little as 1 to 2 degrees Celsius in winter air temperature,” he said. “So very small changes in winter air temperature can lead to large changes in the amount of ice that’s formed.”

Drew Gronewold, a hydrologist with the National Oceanic and Atmospheric Administration’s environmental research laboratory in Ann Arbor, Mich., said surface water temperatures across the Great Lakes have soared. “And on and off, they’ve been pretty high over the past 10, 15 years.”

Minnesota Department of Natural Resources’ Lake Superior area fisheries supervisor Cory Goldsworthy says warmer surface water could also result in a more productive fishery for species such as salmon and brook trout.

Less ice cover could also benefit the shipping industry. Record ice cover in 2014 delayed the start of the shipping season and damaged ships.

http://www.twincities.com/2016/09/11/researchers-say-lake-superior-water-temperature-on-the-rise/