Posts Tagged ‘Antarctic’

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The NLCs are playing a game of hide-and-seek this season, bemusing regular observers.

Spaceweather.com

Jan. 8, 2021:

They’re back. Noctilucent clouds (NLCs), recently missing, are once again circling the South Pole. And, in an unexpected twist, they’ve just appeared over Argentina as well.

“This is a very rare event,” reports Gerd Baumgarten of Germany’s Leibniz-Institute of Atmospheric Physics, whose automated cameras caught the meteoritic clouds rippling over Rio Grande, Argentina (53.8S) on Jan. 3rd:

A second camera recorded the clouds at even higher latitude: Rio Gallegos (51.6S). At this time of year, noctilucent clouds are supposed to be confined to the Antarctic–not Argentina. In the whole history of atmospheric research, NLCs have been sighted at mid-southern latitudes only a handful of times.

“Personally, I am thrilled to see NLCs in Argentina, as I had not expected them to occur so far north,” says Natalie Kaifler of the German Aerospace Center (DLR), who operates a lidar (laser radar) alongside one of Baumgarten’s…

View original post 171 more words

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Is it a coincidence that we’re just past the end of the lowest sunspot cycle for over a century?

Spaceweather.com

Dec. 28, 2020: Something strange is happening 50 miles above Antarctica. Or rather, not happening. Noctilucent clouds (NLCs), which normally blanket the frozen continent in December, are almost completely missing. These images from NASA’s AIM spacecraft compare Christmas Eve 2019 with Christmas Eve 2020:

“The comparison really is astounding,” says Cora Randall of the University of Colorado’s Laboratory for Atmospheric and Space Physics. “Noctilucent cloud frequencies are close to zero this year.”

NLCs are Earth’s highest clouds. They form when summertime wisps of water vapor rise up from the poles to the edge of space. Water crystallizing around specks of meteor dust 83 km (~50 miles) above Earth’s surface creates beautiful electric-blue structures, typically visible from November to February in the south, and May to August in the north.

A crucial point: Noctilucent clouds form during summer. And that’s the problem. Although summer officially started in Antarctica one week…

View original post 237 more words

Antarctica


If they were hoping to see a steady rate of change that matched carbon dioxide emission levels, they were disappointed. Natural variations inconveniently got in the way, two in particular: ‘When two extreme snowfall events in 2009 and 2011 dropped around 600 gigatons of snow and ice, the East Antarctic Ice Sheet thickened so much that it temporarily halted the entire continent’s ice losses, said Wang—a pattern that had previously escaped notice.’
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A new analysis of long-term satellite records shows the East Antarctic Ice Sheet is unexpectedly dependent on fluctuations in weather.

This study may improve models of how much sea levels will rise, says Eos News.

As more coastal communities face the looming threat [Talkshop note: unsupported assertion] of rising sea levels, it’s more important than ever to accurately predict changes in one of the greatest potential sources of sea level rise—the melting of Antarctica’s massive ice sheet.

Recently, scientists analyzed nearly 2 decades’ worth of data from sensitive NASA satellites documenting mass changes in the Antarctic Ice Sheet.

They found the ice inventory ebbed and flowed across the continent in unexpectedly variable patterns.

Traditionally, some groups of Antarctic researchers have assumed the rate of change across the ice sheet is constant, but they drew their conclusions from data sets that spanned only a few years, said Lei Wang, a geodesist at The Ohio State University who will present this research at AGU’s virtual Fall Meeting 2020.

“These long data records give us the capability to characterize the ice sheet’s variation over a range of timescales,” rather than just modeling seasonal variations and short-term trends, Wang said.

Understanding Long-Term Trends

The Antarctic Ice Sheet, the largest mass of ice on Earth, is divided into two unequal portions, with the East Antarctic Ice Sheet covering about two thirds of the continent. The West Antarctic Ice Sheet, although smaller, has historically been more closely studied because it’s melting faster. (The East Antarctic Ice Sheet sits on bedrock above sea level, said Wang, so it is less susceptible to the effects of the warming ocean.) NASA estimates Antarctica has lost 149 billion metric tons of ice per year since 2002.

When so much ice is involved, projections of how sea levels will respond are uncertain—especially when trends already are so difficult to gauge.

Indeed, the field still argues about sea level changes in the past century, said Jim Davis, the study coauthor and a geodesist at the Lamont-Doherty Earth Observatory at Columbia University. “We’ve got to get to the point where we can talk about what’s happening this year in sea level change,” he said.

To do that, researchers need a more sophisticated model of how Antarctica’s shield of ice is evolving.

Full article here.

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Is La Niña having an effect on Antarctica already?

Spaceweather.com

Dec. 2, 2020: Consider it the tip of the iceberg. Noctilucent clouds (NLCs) over the south pole are AWOL.

“Normally we see the first NLCs of the southern season around Nov. 21st,” says Cora Randall of the University of Colorado’s Laboratory for Atmospheric and Space Physics (LASP). “But this year, it’s already December and we’re still waiting.”

Above: What a different one year makes. NASA’s AIM spacecraft took these pictures of NLCs over Antarctica on Nov. 29, 2019 (left) and Nov. 29, 2020 (right)

Missing NLCs is just one of the curious weather patterns currently underway at the southern end of our planet.

Making a list: (1) Earth’s southern ozone hole is not only open, but also the biggest it’s ever been in December. (2) The air above Antarctica is currently at record cold levels for this time of year–the result of an icy polar vortex that refuses to break…

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Credit: earthhow.com


As Accuweather explains here, research has shown that a combination of conditions at solar minimum can create this effect.
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The European Union’s Earth observation program said Tuesday that the ozone hole over Antarctica has swelled to its largest size and deepest level in years, reports Phys.org.

Experts at the Copernicus Atmospheric Monitoring Service said a strong, stable and cold polar vortex has driven the expansion, and called for greater international efforts to ensure countries abide by an international accord to phase out use of ozone-depleting chemicals.

Vincent-Henri Peuch, who heads the service, said in a statement that the ozone hole was “definitely” among the largest in the last 15 years.

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So when global temperatures failed to behave as models expected due to inevitable but hard to predict natural variation, they were forced to re-think – or just think? The GWPF concludes, at the risk of stating the obvious: ‘The lesson of the hiatus is that we do not understand internal climatic variability as much as many think we do, and our predictive power is less than many believe.’
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Researchers from the Universities of Princeton, California, Tokyo, Kyushu and the Scripps Institution of Oceanography, say the recent hiatus in global temperature increase has led to a surge in climate science.

The global effort to understand the global warming hiatus they say has led to increased understanding of some of the key metrics of global climate change such as global temperature and ice-cover.

Searching for an answer to the hiatus, they say, meant that the scientific community grappled with difficulties with these climate metrics, in particular the fact that they do not unequivocally portray the same story about global warming.

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Kangerlussuaq Fjord, Greenland [image credit: notsogreen.com]


Less than a year ago NASA was reporting from Greenland: Jakobshavn Glacier Grows for Third Straight Year, and ‘The glacier grew 22 to 33 yards (20 to 30 meters) each year between 2016 and 2019.’ So this new report may be, to some degree at least, already obsolete since it says: ‘The largest thinning rates were between 4 and 6 m a−1 in Jakobshavn and Kangerlugssuaq glaciers’.
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Sea levels have risen by 14mm since 2003 due to ice melting in Antarctica and Greenland, scientists have said.

Nasa launched a satellite to measure global heights in 2018 and spotted the rise after bouncing laser pulses against sheets of ice, says the London Evening Standard.

The study found that Greenland lost an average of 200 billion tonnes of ice per year, and Antarctica lost an average of 118 billion tonnes.

One billion tonnes of ice is enough to fill 400,000 Olympic-sized swimming pools.

A team led by researchers at the University of Washington compared the data with measurements taken by the satellite between 2003 and 2009.

The findings, published in the journal Science, found the loss of ice from Antarctica and Greenland outweighs any gains from accumulated snow.

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The researchers estimate that carbon dioxide levels in the atmosphere were well over 1000 parts per million in those days, compared to 400+ ppm today. Antarctica and Australia were much closer together.

Antarctica was covered in rainforest in the time of the dinosaurs, according to a new study, Metro News reports.

Researchers have found evidence the South Pole had a climate and forests similar to New Zealand today in a startling discovery. The team discovered soil from an ancient rainforest from the Cretaceous period within 900 km of the South Pole.

The analysis carried out by an international team of researchers of roots, pollen and spores shows the world was a lot warmer than previously thought.

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Significant changes since 2007 or so are observed but not explained, which seems to leave them open to interpretation. To get that ball rolling the recent solar slowdown could be mentioned.
A 2015 NASA study said that ‘an increase in Antarctic snow accumulation that began 10,000 years ago is currently adding enough ice to the continent to outweigh the increased losses from its thinning glaciers.’

Using the latest satellite technology from the European Space Agency (ESA), scientists from the University of Bristol have been tracking patterns of mass loss from Pine Island — Antarctica’s largest glacier, reports SciTechDaily.

They found that the pattern of thinning is evolving in complex ways both in space and time with thinning rates now highest along the slow-flow margins of the glacier, while rates in the fast-flowing central trunk have decreased by about a factor of five since 2007.

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Rinks Glacier, West Greenland
[image credit: NSIDC]


Estimates are always uncertain to some degree – that’s why they’re called estimates. So an uncertain estimate can’t be all that useful. They admit ‘there are still key deficiencies in the models’ — but these are usually ignored when alarmist climate predictions are headlined. As ever, ice-related sea level claims should be taken with a large pinch of salt.

Estimates used by climate scientists to predict the rate at which the world’s ice sheets will melt are still uncertain despite advancements in technology, new research shows.

These ice sheet estimates feed directly into projections of sea-level rise resulting from climate change, says Phys.org.

They are made by measuring how much material ice sheets are gaining or losing over time, known as mass balance, to assess their long-term health.

Snowfall increases the mass of an ice sheet, while ice melting or breaking off causes it to lose mass, and the overall balance between these is crucial.

Although scientists now have a much better understanding of the melting behaviour of ice sheets than they did in previous decades, there are still significant uncertainties about their future melt rates, researchers found.

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Unusual goings-on seen in the skies over New Zealand.

Spaceweather.com

Dec. 4, 2019: An atmospheric wave nearly half as wide as Earth itself is supercharging noctilucent clouds (NLCs) in the southern hemisphere. NASA’s AIM spacecraft detected the phenomenon in this series of south polar images spanning Nov. 27th through Dec. 2nd:

fiveday

“This is a clear sign of planetary wave activity,” says AIM principal investigator James Russell of Hampton University, which manages the Aeronomy of Ice in the Mesosphere mission for NASA.

Planetary waves are enormous ripples of temperature and pressure that form in Earth’s atmosphere in response to Coriolis forces. In this case, a 5-day planetary wave is boosting noctilucent clouds over Antarctica and causing them to spin outward to latitudes where NLCs are rarely seen.

On Dec. 1st, Mirko Harnisch saw the clouds from Dunedin, New Zealand. “I was enjoying the late-evening sky over the Southern Ocean just after 11 pm local time when these wispy blue-ish clouds appeared,”…

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Image credit: extremetech.com


A 2016 article in Astronomy Now reported:
“Scientists found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic and Indian Oceans.

The iron-60 was concentrated in a period between 3.2 and 1.7 million years ago, which is relatively recent in astronomical terms, said research leader Dr. Anton Wallner from The Australian National University (ANU).

“We were very surprised that there was debris clearly spread across 1.5 million years,” said Dr. Wallner, a nuclear physicist in the ANU Research School of Physics and Engineering. “It suggests there were a series of supernovae, one after another.

“It’s an interesting coincidence that they correspond with when the Earth cooled and moved from the Pliocene into the Pleistocene period.” [bold added]

In August this year a new find was reported…
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The rare isotope iron-60 is created in massive stellar explosions, says ScienceDaily. Only a very small amount of this isotope reaches the earth from distant stars.

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‘Long-term’ here means really long-term. The 21k year precession period quoted looks like that of the perihelion.

In the past million years, the high-altitude winds of the southern westerly wind belt, which spans nearly half the globe, didn’t behave as uniformly over the Southern Pacific as previously assumed.

Instead, they varied cyclically over periods of ca. 21,000 years, reports ScienceDaily.

A new study has now confirmed close ties between the climate of the mid and high latitudes and that of the tropics in the South Pacific, which has consequences for the carbon budget of the Pacific Southern Ocean and the stability of the West Antarctic Ice Sheet.

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A reconstruction of the Anglian ice sheet in Precambrian North London (credit: BBC / The Natural History Museum, London)


This might rattle a few cages in climate-land.

An analysis of air up to 2 million years old, trapped in Antarctic ice, shows that a major shift in the periodicity of glacial cycles was probably not caused by a long-term decline in atmospheric levels of carbon dioxide, writes Eric W. Wolff in Nature.
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During the past 2.6 million years, Earth’s climate has alternated between warm periods known as interglacials, when conditions were similar to those of today, and cold glacials, when ice sheets spread across North America and northern Europe.

Before about 1 million years ago, the warm periods recurred every 40,000 years, but after that, the return period lengthened to an average of about 100,000 years.

It has often been suggested that a decline in the atmospheric concentration of carbon dioxide was responsible for this fundamental change.

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Ross Ice Shelf, Antarctica


Is there an element of circular reasoning here? Carbon dioxide levels have historically followed temperature changes, bringing any supposed causation into question.

Upside-down “rivers” of warm ocean water may be one of the causes of Antarctica’s ice shelves breaking up, leading to a rise in sea levels.

But a new study suggests an increase in sea ice may lead to a much more devastating change in the Earth’s climate — another ice age, reports Fox News.

Using computer simulations, the research suggests that an increase in sea ice could significantly alter the circulation of the ocean, ultimately leading to a reverse greenhouse effect as carbon dioxide levels in the ocean increase and levels in the air decrease.

“One key question in the field is still what caused the Earth to periodically cycle in and out of ice ages,” University of Chicago professor and the study’s co-author, Malte Jansen, said in a statement. “We are pretty confident that the carbon balance between the atmosphere and ocean must have changed, but we don’t quite know how or why.”

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Image credit: theozonehole.com


Southern hemisphere spring, that is.

European weather scientists believe the ozone hole over the Antarctic this spring may be one of the smallest since the mid-1980s, says stuff(NZ).

Experts at the Copernicus Atmosphere Monitoring Service (CAMS) have observed strange behaviours of the annual ozone hole this season.

Not only is it already shrinking and well on the way to being about half the size it usually is at this time of year, but also it began forming about two weeks earlier than usual and it is off-centre, away from the South Pole.

They say that is probably the result of the rare sudden stratospheric warming, which has been under way about 30km above Antarctica since last month.

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Antarctica


The lead oceanographer in this research says: “The deep oceans have been warming across much of the world for decades, so we were surprised to suddenly see this trend reversing and stabilizing in the Scotia Sea.”
Carbon dioxide up, warming down – surprising to some it seems.

The supply of dense Antarctic water from the bottom of the ocean to the Atlantic has declined in recent years, says Phys.org.

However, a new study explains for the first time how since 2014 this has stabilized and slightly recovered due to the variability in upstream dense waters, with implications for the global climate.

The study, led by British Antarctic Survey, is published this week in the journal Nature Climate Change.

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Antarctica


Growth of polar sea ice is of course mainly a winter phenomenon, each polar region being continuously dark for several months during that period. The researchers here looked at the role of clouds during the dark Antarctic winter and as one said, “Fewer clouds mean more heat is lost from the ocean.” This then led to higher summer sea ice in some areas.
Which begs the question: why were there fewer winter clouds?

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H/T The Global Warming Policy Forum (GWPF)

BEIJING, April 26 (Xinhua) — Researchers have discovered that lower cloud coverage in the Antarctic can promote sea ice growth.

Unlike the rapid decline of Arctic sea ice in the warming climate, Antarctic sea ice witnessed a modest extension over the past four decades, according to the paper published in the Journal of Geophysical Research-Atmospheres. […]

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Credit: British Antarctic Survey


The EPICA ice cores clearly showed CO2 lagging behind temperature increases – probably by centuries. But observed effects aren’t supposed to precede alleged causes.

European scientists from 10 countries have spent years scouring the Antarctic ice sheet with one ambition in mind: to drill for the oldest-ever ice core.

Now, they have zeroed in on just the spot says IFL Science.

The team have chosen Little Dome C – one of the coldest, most barren places on Earth. For the next five years, they will drill for a 1.5-million-year-old ice core – a frozen timepiece of Earth’s climatic past.

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Antarctica [credit: Wikipedia]


It’s hard to be too surprised by this news even though it’s well into the Antarctic summer.

A British-led expedition to find the Endurance, Sir Ernest Shackleton’s ship, has been defeated by horrendous weather and pack ice – the very conditions that trapped the explorer’s vessel in Antarctica more than a century ago, reports the Daily Telegraph.

The expedition was called off on Thursday after “extreme weather conditions” led to the loss of an autonomous robotic submarine that, it was hoped, would have located the wreck.

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