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Climate: Robotic gliders probe secrets of Southern Ocean

Detailed measurements to help pinpoint rate of ice shelf melt

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Melting Antarctica ice shelves are raising global sea level. bberwyn photo.

Staff Report

FRISCO — The Southern Ocean, surrounding Antarctica, is mostly separated from the rest of the world’s oceans by a sharp temperature boundary and swift currents. But the border between the different masses of water is regularly blurred by giant swirls of water that may be transporting warmer water to the edge of the frozen continent.

Knowing how that process works could help scientists understand how fast Antarctic ice shelves will melt and raise global sea level, according to Caltech scientists who used robotic gliders to track the movement of water in the region. Continue reading

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Climate: Scientists studying old satellite photos to understand current Antarctic sea ice trends

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Icebergs in the Antarctic Sound. bberwyn photo.

Warm October weather leads to rapid melting in Ross Sea region

Staff Report

FRISCO — Persistent warm winds from the north have eaten away at the record sea ice extent around Antarctica the past few weeks.

After reaching a new record in September, the ice extent is now back to the levels of about a year ago, according to the National Snow and Ice Data center’s monthly update.

Along Antarctica’s Pacific coast, including around the Ross Ice Shelf and northern West Antarctic Ice Sheet, air temperatures in October ran 7 to 11 degrees Fahrenheit above average. Temperatures were also warmer than average in the eastern Weddell Sea south of Africa. Continue reading

Russia, China block Antarctica conservation plans

Proposals for vast marine preserves fail for the fourth time

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Plans to protect the Antarctic environment are still on hold. bberwyn photo.

By Summit Voice

FRISCO — Russia and China have once again showed their unwillingness to participate in global efforts to protect the environment in Antarctica by blocking a plan to create new marine reserves off the shore of eastern Antarctica and in the Ross Sea.

Both countries are more interested in exploiting natural resources in the region than in establishing a collaborative framework for sustainable management of the fish and krill. Russia voted for the fourth time to block the proposal for new marine protected areas, while China opposed the plans for the first time. Continue reading

Ozone hole about the same size as last year

A depiction of the ozone hole over Antarctica, courtesy NOAA.

A depiction of the ozone hole over Antarctica, courtesy NOAA.

Ozone-depleting chemicals decreasing in atmosphere, but weather plays big role in year-to-year variability

Staff Report

FRISCO — The ozone hole over Antarctica didn’t change much from last year, scientists said this week, pointing to weather and climate variability as key factors in year-to-year variability.

The single-day maximum area was similar to that in 2013, which reached 9.3 million square miles. The largest single-day ozone hole ever recorded by satellite was 11.5 million square miles) on Sept. 9, 2000. Overall, the 2014 ozone hole is smaller than the large holes of the 1998–2006 period, and is comparable to 2010, 2012, and 2013. Continue reading

Antarctica’s ice-free fringe needs more protection

Invasive species a huge threat to sparse ecosystems, scientists report

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Tourists on Dundee Island hike past birds and pinnipeds. bberwyn photo

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Tourists hiking on Deception Island. bberwyn photo

Staff Report

FRISCO — The tiny ice-free fringes of Antarctica are especially prone to ecosystem disruption, including invasive species, an Australian science team warned earlier this year after taking a close look at how human use is concentrated in those slivers of dry land.

Antarctica has over 40,000 visitors a year, and more and more research facilities are being built in the continent’s tiny ice-free area. Most of the Antarctic wildlife and plants live in the ice-free areas – and this is also where people most visit.

Most tour operators in Antarctica follow strict guidelines set to protect ecosystems, including at least basic decontamination procedures, but those measures might not be enough, especially as global warming makes ice-free zones more susceptible to invasive species. Continue reading

Climate studies probe growth of Antarctic sea ice

‘The planet as a whole is doing what was expected in terms of warming. Sea ice as a whole is decreasing as expected …’

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Sea ice is expanding around Antarctica, and scientists say wind, snow and melting land ice are key factors in the growth bberwyn photo.

The map at right shows Antarctic ice concentration on September 22, 2014, the date of the record high. Areas where the surface was less than 15% ice covered are deep blue; areas that were up to 100% ice covered are shades of light blue to white. The orange line shows the 1981-2010 median extent for September 22. (Median means in the middle: half of the years in the record had smaller ice extents than this, and half had larger extents.) The graph below the map shows daily Antarctic sea ice extent over the course of the year. The black line traces the 1981-2010 average, and the gray shading shows the range of variability (2 standard deviations from the mean). The previous record high extent (2013) is a dashed green line; the 2014 year to date is a light green line. NSIDC reported that the 2014 extent rose nearly 4 standard deviations above the 1981-2010 mean.

The map above shows Antarctic ice concentration on September 22, 2014, the date of the record high. Areas where the surface was less than 15% ice covered are deep blue; areas that were up to 100% ice covered are shades of light blue to white. The orange line shows the 1981-2010 median extent for September 22. (Median means in the middle: half of the years in the record had smaller ice extents than this, and half had larger extents.)
The graph below the map shows daily Antarctic sea ice extent over the course of the year. The black line traces the 1981-2010 average, and the gray shading shows the range of variability (2 standard deviations from the mean). The previous record high extent (2013) is a dashed green line; the 2014 year to date is a light green line. NSIDC reported that the 2014 extent rose nearly 4 standard deviations above the 1981-2010 mean. Courtesy NOAA.

By Summit Voice

FRISCO — Along with shifting wind patterns in the southern hemisphere, melting land ice may be contributing to recent record extents of floating sea ice around Antarctica. The melting ice and snow adds fresh water — which freezes morel easily — to the salty Southern Ocean, scientists said in a release this week, explaining the multi-year trend of expanding Antarctic sea ice.

But the increase doesn’t balance the loss of sea ice at the other end of the Earth. Arctic sea ice has declined by an average of 20,800 square miles per year; the Antarctic has gained ice at a rate of about a third of that, by an average of 7,300 square miles per year.

This week, the National Snow and Ice Data Center (NSIDC) reported that Antarctic sea ice extent set a new record high for daily extent: 20.11 million square kilometers (7.76 million square miles), the highest since satellite observations started in the late 1970s.

In July, a European study called into question the recent measurements, citing inconsistencies in computer models.

Other studies suggest the growth is only temporary, and that Antarctic sea ice will ultimately decline dramatically in the decades ahead.

The ice trackers matched this year’s late season ice surge with strong southerly winds blew over the Weddell Sea. Without any nearby land masses to constrain growth, those winds tend to push the ice northward. Continue reading

Climate: Polar paradox?

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September trend for Arctic sea ice extent is down, down, down. Courtesy NSIDC.

Arctic sea ice bottoms out; Antarctic sea ice hits new high

Staff Report

FRISCO — Even without remarkably warm weather patterns across the Arctic, summer sea ice dropped to the sixth-lowest extent on record this year, while at the other end of the Earth, sea ice around Antarctica swelled to a record extent.

Through 2014, Arctic sea ice has now been declining at a rate of 13.3 percent per decade relative to the 1981 to 2010 average. The ten lowest September ice extents over the satellite record have all occurred in the last ten years. Continue reading

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