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Global warming: Is Arctic ice at a tipping point?

CU Boulder researchers lead effort to study changes in the Arctic sea ice

NASA satellite images show the state of Arctic ice from a distance, but a new two-year research efforts should yield more clues about global warming impacts to the planet's icebox.

By Summit Voice

SUMMIT COUNTY — A research effort led by the University of Colorado Boulder is launching a two-year study of Arctic sea ice to determine whether areas like the Beaufort Sea and the adjacent Canada Basin have passed a ‘tipping point’ and now are essentially sub-Arctic zones where ice disappears each summer.

Such ice loss could be causing fundamental changes in ocean conditions, including earlier annual blooms of phytoplankton, which are microscopic plant-like organisms that drive the marine food web.

The team will use unmanned aircraft and satellites to ocean buoys in order to understand the characteristics and changes in Arctic sea ice, which was at 1.67 million square miles during September 2011, more than 1 million square miles below the 1979-2000 monthly average sea ice extent for September — an area larger than Texas and California combined.

Critical ocean regions north of the Alaskan coast have experienced record warming and decreased sea ice extent unprecedented in human memory, said CU-Boulder Research Professor James Maslanik, who is leading the research effort.

The scientists will take a close look at the Beaufort Sea, considered a “marginal ice zone” where old and thick multiyear sea ice has failed to survive during the summer melt season in recent years, said Maslanik, of CU-Boulder’s Colorado Center for Astrodynamics Research in CU’s engineering college. Such marginal ice zones are characterized by extensive ice loss and a strong “ice-albedo” feedback.

“Sea ice is lost when the darker ocean absorbs more sunlight in the form of heat in the summers, resulting in potentially thinner sea ice that re-forms the following winter,” Maslanik said.  “This positive feedback between heat absorption by the ocean and accelerated melting becomes reinforcing in itself.” Marginal ice zones also are characterized by significant human and marine mammal activity, he said.

There was a record loss of sea ice cover over the Arctic in 2007, he said. “In some areas of the Arctic Ocean the multiyear ice rebounded, but in the Beaufort Sea we did not see that kind of multiyear ice persistence like we used to see,” said Maslanik, who also is a research professor in the aerospace engineering sciences department.

The vast majority of climate scientists believe shrinking Arctic sea ice in recent decades is due to rising temperatures primarily caused by human activities that pump huge amounts of heat-trapping gases like carbon dioxide into the atmosphere.

The new $3 million study led by Maslanik, “The Marginal Ice Zone Observations and Processes EXperiment,” or MIZOPEX, is being funded by NASA. In addition to satellite data, the study will use small, unmanned aircraft that can fly below the clouds, observe the same location continuously for hours and make more precise measurements of sea ice composition and sea surface temperatures. Maslanik and his CU-Boulder team previously used unmanned aircraft to assess ice conditions both in the Arctic and in Antarctica.

The MIZOPEX arsenal also will include floating buoys that measure ocean temperatures. CU-Boulder engineering faculty members Scott Palo and Dale Lawrence and their graduate students are converting miniaturized versions of dropsondes — standard weather reconnaissance devices designed to be dropped from aircraft and capture data as they fall toward Earth — into the buoys that will be deployed by the UAS.

The modified dropsondes, which were developed at CU-Boulder for use in Antarctica, will be combined with CU-designed miniature unmanned aircraft that will land on the ocean near sea ice floes. Such floes are critical to several species of Arctic wildlife, including polar bears, walruses and seals.

The buoys and unmanned craft will collect sea surface and subsurface temperatures to about a meter deep, while the overflying unmanned planes and satellites measure temperatures at the surface, Maslanik said.

“We want to know if the warming is just at the ocean surface or if there is additional heat getting into the mixed layers of the upper ocean, either from absorbed sunlight or from ocean currents, that could be contributing to sea ice melt.”

The team plans to gather information over 24-hour cycles to determine how the ocean and ice are reacting to atmospheric changes. “Understanding what’s happening in the water is critical to forecasting what will happen to ice in the near term, as well as in the decades to come,” said MIZOPEX team scientist Betsy Weatherhead of CU-Boulder’s Cooperative Institute for Research in Environmental Sciences.

“We’ve never had the data before,” Weatherhead said. “With this new instrumentation, we’ll be able to ask questions and test theories about the drivers of ice melt.”

The MIZOPEX effort involves CU-Boulder, NASA, Fort Hays State University in Kansas, Brigham Young University, the University of Alaska-Fairbanks, NOAA, the University of Washington and Columbia University.  Ball Aerospace Systems Group of Boulder also is collaborating on the project.

Other MIZOPEX project scientists from CU include Brian Argrow, Sandra Castro, Ian Crocker, William Emery, Eric Frew and Mark Tschudi.  Argrow directs the CU-headquartered Research and Engineering Center for Unmanned Vehicles, a university-government-industry partnership for the development and application of unmanned vehicle systems.

For more information on MIZOPEX visit http://ccar.colorado.edu/mizopex/index.html.

For more information on CU-Boulder’s Research and Engineering Center for Unmanned Vehicles visit http://recuv.colorado.edu/.

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3 Responses

  1. More scientific evidence to understanding what is taking place up there.

  2. Has anyone considered the underwater volcano activity in these areas? Hot mudflows melt ice.

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