ESA Cryosat-2 finds sharp rise in Antarctica ice loss

Three years of observations from ESA’s CryoSat-2 satellite show that the Antarctic ice sheet is now losing 159 billion tonnes of ice each year – twice as much as when it was last surveyed.

The polar ice sheets are a major contributor to the rise in global sea levels, and these newly measured losses from Antarctica alone are enough to raise global sea levels by 0.45 mm each year.

These latest findings by a team of scientists from the UK’s Centre for Polar Observation and Modelling show that the pattern of imbalance continues to be dominated by glaciers thinning in the Amundsen Sea sector of West Antarctica.

Between 2010 and 2013, West Antarctica, East Antarctica and the Antarctic Peninsula lost 134, 3 and 23 billion tonnes of ice each year, respectively.

The average rate of ice thinning in West Antarctica has increased compared to previous measurements, and this area’s yearly loss is now one third more than measured over the five years before CryoSat’s launch.

Launched in 2010, CryoSat-2 carries a radar altimeter that can measure the surface height variation of ice in fine detail, allowing scientists to record changes in its volume with unprecedented accuracy.

CryoSat-2 surveys almost all – 96% – of the Antarctic continent, reaching to within 215 km of the South Pole. In addition, it has increased coverage over coastal regions, where today’s ice losses are concentrated.

Andrew Shepherd

“Thanks to its novel instrument design and to its near-polar orbit, CryoSat-2 allows us to survey coastal and high-latitude regions of Antarctica that were beyond the capability of past altimeter missions, and it seems that these regions are crucial for determining the overall imbalance,” said Prof. Andrew Shepherd from the University of Leeds, UK, who led the study.

In particular, newly mapped areas by CryoSat-2 in West Antarctica have now brought altimeter observations closer to estimates based on other approaches.

“We find that ice losses continue to be most pronounced along the fast-flowing ice streams of the Amundsen Sea sector, with thinning rates of 4-8 m per year near to the grounding lines, where the ice streams lift up off the land and begin to float out over the ocean, of the Pine Island, Thwaites and Smith Glaciers,” said Dr Malcolm McMillan from the University of Leeds, UK, and lead author of the study.

Malcolm McMillan

This area has long been identified as the most vulnerable to changes in climate.

Recent assessments say its glaciers may have passed a point of irreversible retreat.

“Although we are fortunate to now have, in CryoSat-2, a routine capability to monitor the polar ice sheets, the increased thinning we have detected in West Antarctica is a worrying development,” said Prof. Shepherd.

“It adds concrete evidence that dramatic changes are under way in this part of our planet. The challenge is to use this evidence to test and improve the predictive skill of climate models.”

The findings were published in Geophysical Research Letters.

Man-made CFC gases pose additional threat to ozone layer

Dealing with the hole in the ozone layer has been one of the most successful international science projects

Scientists have identified four new man-made gases that are contributing to the depletion of the ozone layer.

Two of the gases are accumulating at a rate that is causing concern among researchers.

Worries over the growing ozone hole have seen the production of chlorofluorocarbon (CFC) gases
restricted since the mid 1980s.

But the precise origin of these new, similar substances remains a mystery, say scientists.

Lying in the atmosphere, between 15 and 30km above the surface of the Earth, the ozone layer plays a critical role in blocking harmful UV rays, which cause cancers in humans and reproductive problems in animals.

Scientists from the British Antarctic Survey were the first to discover a huge "hole" in the ozone over Antarctica in 1985.

The evidence quickly pointed to CFC gases, which were invented in the 1920s, and were widely used in refrigeration and as aerosol propellants in products like hairsprays and deodorants.

Remarkably, global action was rapidly agreed to tackle CFCs and the Montreal Protocol to limit these substances came into being in 1987.

A total global ban on production came into force in 2010.

Now, researchers from the University of East Anglia have discovered evidence of four new gases that can destroy ozone and are getting into the atmosphere from as yet unidentified sources.

The Halley Research Station in Antarctica, where the hole in the ozone layer was first discovered

Three of the gases are CFCs and one is a hydrochlorofluorocarbon (HCFC), which can also damage ozone.

"Our research has shown four gases that were not around in the atmosphere at all until the 1960s which suggests they are man-made," said lead researcher Dr Johannes Laube.

Johannes Laube.

The scientists discovered the gases by analysing polar firm, perennial snow pack. Air extracted from this snow is a natural archive of what was in the atmosphere up to 100 years ago.

Grim discovery
The researchers also looked at modern air samples, collected at remote Cape Grim in Tasmania.

They estimate that about 74,000 tonnes of these gases have been released into the atmosphere. Two of the gases are accumulating at significant rates.

"The identification of these four new gases is very worrying as they will contribute to the destruction of the ozone layer," said Dr Laube.

"We don't know where the new gases are being emitted from and this should be investigated. Possible sources include feedstock chemicals for insecticide production and solvents for cleaning electronic components."

"What's more, the three CFCs are being destroyed very slowly in the atmosphere - so even if emissions were to stop immediately, they will still be around for many decades to come," he added.

The four new gases have been identified as CFC-112, CFC112a, CFC-113a, HCFC-133a 

• CFC-113a has been listed as an "agrochemical intermediate for the manufacture of pyrethroids", a type of insecticide once widely used in agriculture 
• CFC-113a and HCFC-133a are intermediaries in the production of widely used refrigerants 
• CFC-112 and 112a may have been used in the production of solvents used to clean electrical components

Other scientists acknowledged that while the current concentrations of these gases are small and they don't present an immediate concern, work would have to be done to identify their origin.

"This paper highlights that ozone depletion is not yet yesterday's story," said Prof Piers Forster, from the University of Leeds.

"The concentrations found in this study are tiny. Nevertheless, this paper reminds us we need to be vigilant and continually monitor the atmosphere for even small amounts of these gases creeping up, either through accidental or unplanned emissions.

"Of the four species identified, CFC-113a seems the most worrying as there is a very small but growing emission source somewhere, maybe from agricultural insecticides. We should find it and take it out of production."

The research 'Newly detected ozone-depleting substances in the atmosphere' has been published in the journal, Nature Geoscience.

NASA AIM: Electric Blue Noctilucent Clouds over Antarctica - Video

NASA AIM records Noctilucent clouds, Earth's highest clouds, appeared over the South Pole earlier than usual this year. Water molecules mixed with meteor smoke at the edge of space, creates this phenomenon.

Credit: NASA

ESA CryoSat maps largest-ever flood beneath Antarctica

Location of the crater in Victoria Land, East Antarctica at about 73ºS and 156ºE. The colour scale shows height derived from CryoSat data. The crater is located within the white box. Credit: ESA/M. McMillan

ESA's CryoSat satellite has found a vast crater in Antarctica's icy surface. Scientists believe the crater was left behind when a lake lying under about 3 km of ice suddenly drained.

Far below the thick ice sheet that covers Antarctica, there are lakes of fresh water without a direct connection to the ocean.

These lakes are of great interest to scientists who are trying to understand water transport and ice dynamics beneath the frozen Antarctic surface – but this information is not easy to obtain.

One method is to drill holes through kilometres of ice to the water – a difficult endeavour in the harsh conditions of the polar regions.

But instead of looking down towards the ice, a team of European scientists is looking to the sky to improve our understanding of subglacial water and its transport.

By combining new measurements acquired by CryoSat with older data from NASA's ICESat satellite, the team has mapped the large crater left behind by a lake, and even determined the scale of the flood that formed it.

From 2007 to 2008, six cubic kilometres of water – about the same amount that is stored in Scotland's Loch Ness – drained from the lake, making it the largest event of its kind ever recorded.

That amount of water equals a tenth of the melting that occurs beneath Antarctica each year.

Since the end of 2008, the lake appears to be refilling but six times slower than it drained. It could take decades to reform.

Scientist Conquers Antarctica with Super-Tiger Air Balloon

The Super Tiger Balloon getting ready for its release at McMurdo ice station Antarctica.

Dr. John E Ward, an Astrophysicist at Washington University, St. Louis, Missouri, has been in Antarctica since October getting ready for the record attempt.

Dr. Ward is part of a NASA research project called Super-TIGER (Super Trans-Iron Galactic Element Recorder), a two-ton machine that collects cosmic-ray particles at the top of the atmosphere.

Although cosmic rays were discovered over 100 years ago, physicists are still uncertain about where in the Universe they originate.

Dr. Ward and his team are trying to show that cosmic rays come from cosmic explosions within groups of enormous hot stars, known as OB associations.

The Super-TIGER instrument is about the size of a snooker table and weighs in at around two tons.

It was launched from the Ross Ice Shelf, Antarctica on a NASA high-altitude balloon on the 9th December 2012.

The balloon itself is massive, weighing some 5,000 lbs. It is made of plastic and is a little thicker than cling film.

An image of the two and a quarter turns taken around the South Pole by the Super Tiger

The balloon has circled the South Pole twice, at an altitude of around 130,000 feet.

So far the team have collected over 50 million cosmic-ray particles.

This morning Dr. Ward’s balloon flight surpassed the previous record of 42 days, set in 2004 by an Irish man, Jojo Boyle from Donegal, with the CREAM cosmic-ray project.

It is expected that Dr. Ward’s balloon will stay in the air for another 10-14 days.

When the balloon is back close to McMurdo Station, it will be brought down by a remote controlled explosion triggered from a NASA satellite that will rip a massive hole in the balloon and allow the Super-TIGER instrument to fall back to Earth on a parachute.

Dr. Ward will then fly in a small Twin Otter ski plane to whereever in Antarctica that the parachute lands.

His first job will be to secure the valuable data disks before dismantling and recovering the two ton instrument. Dr. Ward is expected to leave Antarctica at the close of the summer season in February 2013.

Geolocator: Tracking migratory Birds

A miniature light level logger (geolocator) for tracking animal movements for long periods has been designed and developed by engineers at the British Antarctic Survey, but is now under license to UK company Biotrack (as of November 2011).

The devices can be used for tracking over long distances in any application where the logger usually has an unobscured view of natural light level at dawn and dusk. The loggers must be retrieved for data download.

The light level geolocator is a miniature, light weight archival tag recording essential light level information which can be processed to give location latitude and longitude.

The devices are small, have low weight and drag, long lasting and cost effective. Although not as accurate as GPS or ARGOS, this method allows a much cheaper and much smaller device to be constructed which records for a far longer time (many years).

For seabirds, logging of wet/dry information and sea surface temperature can also be included. The wet/dry recording has been developed to measure the activity of the birds, and the temperature information, when correlated with satellite data, can be used to improve the location fix.

The loggers work worldwide wherever there is dawn and dusk, and have been used so far on a number of species including geese, albatross, penguins, shearwaters, gannets, skuas, fulmars, ducks, shags and seals.

Being so small, they can be attached to leg rings of larger seabirds, thus avoiding problems associated with platform gluing and harnesses.

Accuracy is in the region of +/-150km and uncertainty is caused mainly by shading (including cloud and foliage), interference (non direct sun and artificial light), and for latitude, proximity to equinox and the equator.

Now that the current devices weigh in under 1.5g, use of them to track songbird species is now beginning to be explored.

A leg-loop harness, similar to the Rappole-Tipton method has been favoured so far. For back mounting with a harness, the supplier has developed devices with the light sensor on a stalk to clear the plumage of the bird.

Arctic Tern migration revealed here

For a great article from Kent McFarland of the Vermont Center for Ecostudies detailing recent use with passerines, see here

Short Sharp Science: Asteroid strike may have frozen Antarctica

Short Sharp Science: Asteroid strike may have frozen Antarctica

A massive asteroid hit the Timor Sea around 35 million years ago - and the impact apparently contributed to the formation of the Antarctic ice sheets.

So says Andrew Glikson, a specialist in the study of extraterrestrial impacts, from the Planetary Science Institute at the Australian National University in Canberra, who analysed a dome found 2.5 kilometres below the Timor Sea, about 300 kilometres off Australia's north west coast.

Based on the structure of the dome, called Mount Ashmore, there were two obvious explanations for its formation: from a mud volcano or from the movement of tectonic plates.

But using a barrage of tests including scanning electron microscopy and seismic surveys, as well as chemical analysis of the rocks, Glikson concluded that the dome was the result of an asteroid crashing into the Earth at such speeds that it caused the Earth's crust to rebound (Australian Journal of Earth Sciences, DOI: 10.1080/08120099.2010.481327).

Images from scanning electron microscopy showed that the cracks and pulverised rocks throughout the dome were unlike those seen in tectonic plate movements.

DLR Capture Iceberg collides on ice shelf in the Antarctica

Looking like a needle of ice and snow, iceberg B-15K was caught in the act by the German Aerospace Center's (Deutsches Zentrum für Luft- und Raumfahrt; DLR) TerraSAR-X satellite as it collided with an ice shelf in Atka Bay, Antarctica. Scientists had long been observing as the 54-kilometre long and 5-kilometre wide iceberg was driven around Antarctica by ocean currents. Then, on 11 February 2010, it crashed into the edge of the ice shelf in Atka Bay.



Like a needle of ice and snow, the iceberg B-15K was caught in the act by the German Aerospace Center's (Deutsches Zentrum für Luft- und Raumfahrt; DLR) TerraSAR-X satellite as it collided with an ice shelf. Scientists had long been watching as the 54-kilometre long and 5-kilometre wide iceberg was being driven around Antarctica by ocean currents. Then, on 11 February 2010, it crashed into the edge of the ice shelf in Atka Bay.

The Neumayer station, visible as a bright spot in this TerraSAR-X image, was not affected by the collision. This image, taken on 10 February 2008, shows the station as well as the transport routes to the ice shelf.

To read the full article on the DLR website, click here