Monday, November 23, 2009

Tundra Swans in Chequamegon Bay

For the last week or so we have had about twenty tundra swans hanging out in Chequamegon Bay near the mouth of Fish Creek. The swans are on their way to Chesapeake Bay. Tundra swans are a larger-than-life reminder of the amazing migration many birds make from their arctic breeding/nesting grounds across North America to their wintering sites.

Some places along the Upper Mississippi receive thousands of swans each fall near Alma, WI and Weaver Bottoms, MN.

On a day like today, with a warm gray mist hanging over the lake, I feel lucky to witness these beautiful birds on their long journey.



Tundra Swans at Alma, Wisconsin by rontaube

Monday, November 9, 2009

Underwater Glider

















The Great Lakes Observing System reported on the University of Minnesota-Duluth launching an underwater glider in Lake Superior.

On Sept. 26, 2009, Jay Austin, professor at the University of Minnesota - Duluth, successfully recovered his Autonomous Underwater Glider (AUG) after a nine-day data collecting mission. During its mission, it "flew" approximately 250km in the western arm of Lake Superior, making an equivalent of nearly 1000 conductivity, temperature and depth (CDT) casts.

The AUG's first mission was to move back and forth along the waters near Two Harbors collecting data, making 16 crossings of the shelf over about 4 days. After that, the glider swam over to the Wisconsin shore and back, producing a 30-km long section (see chart for raw, not-yet post-processed data). According to Austin, the cross-lake sections took about 24 hours to complete. He recalled the glider typically ran at about 35cm/s, slower than advertised, but thinks there are some things he can do to improve this.

The AUG is designed to collect real-time data at least once every three hours or when the AUG has completed a mission, whichever comes first. "While running it can be a bit un-nerving, this thing is really cool and provides a sort of data impossible to collect from ships or moored platforms," Austin said. "Hopefully this is just the first of many gliders in the Great Lakes!"

GLOS assisted with financing the daily operating costs which were on the order of $100-$150 per day (excluding boat time to get it out and back). Currently, the data the AUG is collecting is limited to temperature. Eventually Austin would like to collect data on a wide range of parameters, from oxygen levels to chlorophyll content.

For more information contact Jay Austin, 218-726-8773 or jaustin@d.umn.edu.