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October 2, 2012

UW scientists team with Coast Guard to explore ice-free Arctic Ocean

With the melting ice in the Arctic, U.S. Coast Guard crews based in Alaska have taken on a new challenge: carefully deploying scientific equipment through cracks in the ice from an airplane hundreds of feet in the air.

It’s all part of a new partnership that has evolved since disappearing Arctic ice has opened vast new frontiers ­­– for the Coast Guard and for University of Washington scientists.

This year, the lowest ebb of Arctic sea ice covered less area than at any time since scientists began recording it. From 1979 to 2000, the average low point for the year was 7 million square kilometers, or 2.7 million square miles. This year, it’s less than half as much – 3.4 million square kilometers.

“It used to be that the ice just pulled back a bit from the beach each year,” said Jamie Morison, an oceanographer at the UW’s Applied Physics Laboratory. “Now we’re seeing huge areas of open water.”

Suddenly faced with a great expansion of the water over which it must monitor ship traffic and perform search-and-rescue operations, the Coast Guard has begun making regular flights over the Arctic, taking off from Kodiak, Alaska. UW researchers, equally eager to explore the newly accessible ocean, are among those who have tagged along on regular Coast Guard flights, known as Arctic Domain Awareness flights,  to deploy scientific equipment.

The UW is leading a project known as the Seasonal Ice Zone Reconnaissance Surveys that aims to take repeated ocean, ice and atmospheric measurements in the Beaufort and Chukchi Seas, north and west of Alaska.

Researchers are able to arrange for deployment of equipment to take those measurements via the Coast Guard’s scheduled C-130 Hercules aircraft tours. They have flown monthly this summer, with Coast Guard crews deploying 19 probes as far as 80 degrees north latitude, north of most land masses. The final flight will be in mid-October, after which it gets too dark to travel very far and the ice returns.

The researchers are studying the impact of the lack of ice cover. For instance, ocean surface temperature can be 5 or 6 degrees warmer without ice. Because there’s no ice to block solar radiation, the layer of warmer water extends deeper and that affects circulation patterns and slows the growth of ice during the winter. Changes in the ocean surface temperatures can also have profound effect on the atmosphere and changes in the temperature, humidity and cloud cover can in turn affect how fast sea ice melts or grows.

“For the first time we’re measuring ocean and atmosphere in an integrated way and trying to track the changes,” said Axel Schweiger, a climatologist and chair of the Applied Physics Laboratory’s Polar Science Center.

UW scientists involved with the International Arctic Buoy Program, designed to monitor sea level pressure, surface air temperature and ice motion, have also taken advantage of the Coast Guard flights. The multiagency program is led by the UW’s Polar Science Center and has deployed hundreds of buoys in the Arctic since 1979.

The researchers have modified some equipment so it can be tossed out of airplanes rather than deployed by ship. One large buoy used by the International Arctic Buoy Program carries instruments that transmit air temperature and pressure information via satellite and gets rolled out of the back of the airplane flying 300 feet above the surface. At that height, a parachute fills and releases in time to temper the buoy’s landing. If the buoy is dropped from higher it might hit too hard, damaging the instruments; too low and the parachute may drag the buoy sideways in the water. The researchers have learned about both issues the hard way.

Coast Guard crews have also been deploying 3-foot-long, tube-shaped instrument packages out the side door of the planes. Once the package hits the water, it drops a torpedo-shaped sensor probe that travels to a depth of 1,000 meters, or 3,280 feet, in about 10 minutes. The probe is connected by a thin copper wire to a radio transmitter that floats on the surface. The probe sends data about water temperature and salinity up the thin wire to the surface transmitter, which relays it by VHF radio back to the airplane circling above.

Without the planes, the researchers would have to hire a ship, usually an icebreaker, to bring the instruments to the targeted location. Or, they could pay for a specialized research aircraft, an expensive proposition, particularly for research that benefits from weekly or monthly expeditions. “You won’t get that kind of repeat coverage with a designated research aircraft,” Schweiger said.

The Coast Guard appears to get some value from taking the scientists along too. Data from the buoys about air pressure and temperature is fed into the world meteorological network. “This weather data helps them fly safely,” said Ignatius Rigor, a mathematician at the Applied Physics Laboratory who coordinates the International Arctic Buoy Program.

The scientists can also field questions from the crew about ice thickness and the weather in the area, Morison said.

The data they collect is already being used by many institutions as well, including the National Snow and Ice Data Center, which closely monitors Arctic sea ice.

The researchers hope to be able to continue their collaboration with the Coast Guard in years to come.

The Seasonal Ice Zone Reconnaissance Surveys program is funded by the Office of Naval Research and the International Arctic Buoy Program is funded by the 20 research and operational institutions that comprise the program.

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For more information, contact Schweiger at axel@apl.washington.edu or 206-543-1312.

Tag(s): climate change • College of the Environment • Department of Atmospheric and Climate Science • oceanography • polar science • sea ice

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