Environment: Antarctic ozone hole closes early this year

Posted on December 22, 2012 by Bob Berwyn

Warmer stratosphere, active polar vortex help speed seasonal recovery

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A graphic from the WMO shows the progression of the Antarctic ozone hole.

By Summit Voice

FRISCO — Relatively warm stratospheric temperatures helped limit the size of this year’s Antarctic ozone hole, which disappeared completely by Nov. 10, earlier than in recent years.

Using data gathered from ground stations and weather balloons, the World Meteorological Organization said the warmer temps at an elevation of about 20 kilometers limited the formation of polar stratospheric clouds which, through a chemical chain reaction between water, nitric acid and halogenated reservoir gases cause ozone loss. In this respect, the 2012 ozone hole was similar to the one in 2010, when a sudden stratospheric warming in July and August gave rise to a smaller amount of polar stratospheric clouds than usual. (more…)

Filed under: air quality, Antarctica, climate and weather, Environment, seasons | Tagged: , , , , , | 3 Comments »

Climate: Shifting winds drive Antarctic sea ice changes

Posted on November 11, 2012 by Bob Berwyn

New study pinpoints regional growth and decline of Antarctic sea ice

Researchers are starting to understand how shifting wind patterns are driving changes in Antarctic sea ice extent. Bob Berwyn photo.

By Bob Berwyn

FRISCO — After compiling more than 5 million individual daily ice motion measurements of sea ice motion around Antarctica, scientists from the U.S. and U.K. say they’re sure that the recent increases in Antarctic sea ice are linked to changing wind patterns in the region.

Essentially, the circumpolar winds are strengthening around Antarctica, said Dr. Ron Kwok, of NASA’s Jet Propulsion Laboratory in California. Why those winds are intensifying, and whether it’s linked with a warming atmosphere remains as a huge question, Kwok said. View a mult-year animation of Antarctic sea ice changes here.

“We are basically finding evidence of change over a long time scale … That’s why it’s inportant to quantify the mechanisms,” he said. “It’s probably associated with a changing climate. The Antarctic sea ice interacts with the global climate system very differently than that of the Arctic, and these results highlight the sensitivity of the Antarctic ice coverage to changes in the strength of the winds around the continent.” (more…)

Filed under: Antarctica, climate and weather, Environment, global warming, Uncategorized | Tagged: , , , , , , , , , | Leave a Comment »

Environment: Antarctic ozone hole getting smaller

Posted on October 26, 2012 by Bob Berwyn

This year’s ozone hole over Antarctica was the second-smallest in 20 years, according to NASA.

Warmer temps in the lower stratosphere helped shrink the hole this year

By Summit Voice

FRISCO — The Antarctic ozone hole shrank to its second-smallest size in the past 20 years, down to “only” 8.2 million square miles, just barely big enough to cover all of North America.

NASA researchers said natural variations in weather patterns are the biggest factor in determining the size of the hole, which allows harmful ulraviolet radiation to reach the surface of the Earth. This year, those patterns generated warmer-than-average stratospheric temperatures in the region.

The ozone hole reached its maximum size Sept. 22. The average size of the 2012 ozone hole was 6.9 million square miles.  The largest ozone hole on record was in Sept. 6, 2000, when it reached 11.5 million square miles. (more…)

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Environment: Antarctic mosses stunted by climate change

Posted on December 4, 2011 by Bob Berwyn

Trace radioactivity from nuclear test era helps researchers measure growth of rare Antarctic plants

There aren't many green plants growing on Antarctica, but the few mosses that take advantage of freshwater icemelt are showing signs of being affected by human-caused climate change. PHOTO BY BOB BERWYN.

Moss growing near freshwater runoff on Dundee Island. PHOTO BY BOB BERWYN.

By Bob Berwyn

SUMMIT COUNTY —Some of the earliest explorers racing each other to reach the South Pole found fossil fragments showing that lush forests once grew on Antarctica, when it was part of the supercontinent, Gondwanaland.

In this era, it’s difficult to find any signs of vegetation in Antarctica, but a few sparse patches of moss suggest that climate change in recent decades is having an impact on the few plants that do grow in the short summer season.

Australian scientists say that, even though we tend to think of Antarctica as the last untouched wilderness preserved from human impact, it is still affected by anthropogenic climate change. (more…)

Filed under: biodiversity, climate and weather, Environment, global warming, Summit County news | Tagged: , , , , | 2 Comments »

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