Sunny arctic weather causing more ice melt

BOULDER, Colo., April 21 (UPI) -- U.S. scientists say they've determined the shrinking expanse of Arctic Ocean ice is becoming increasingly vulnerable to summer sunshine.

The study by scientists at the National Center for Atmospheric Research and Colorado State University found unusually sunny conditions contributed to last summer's record loss of arctic ice, but that similar weather conditions during past summers did not have comparable impacts.

The researchers said their findings indicate summer sunshine in the arctic produces more pronounced melting than during past years, largely because there is now less ice to reflect solar radiation back into space. As a result, they said the presence or absence of clouds now has greater implications for sea ice loss.

Last summer's loss of Arctic Ocean ice set a modern-day record, with the ice extent shrinking to a minimum of about 1.6 million square miles. That was 43 percent less ice coverage than in 1979, when accurate satellite observations began.

The scientists said their study -- which utilized observations from instruments on a new group of National Aeronautics and Space Administration satellites -- will be published Tuesday in the journal Geophysical Research Letters.