NASA ER-2: Melt ponds shine in MABEL laser altimeter flight images

Engineers installed a new camera system on MABEL for its summer 2014 campaign, so scientists could better understand what it measured during flights. 

A key goal of the Alaska-based campaign was to measure glacial melt ponds like this one, photographed July 16. 

Credit: NASA

Even from 65,000 feet above Earth, aquamarine melt ponds in the Arctic stand out against the white sea ice and ice sheets. These ponds form every summer, as snow that built up on the ice melts, creating crystal clear pools.

On July 16 and July 17, NASA's ER-2 aircraft flew above Alaskan glaciers and to the North Pole, carrying an instrument called the Multiple Altimeter Beam Experimental Lidar (MABEL).

MABEL is a laser altimeter, measuring the elevation of glaciers, mountains, forests and other topography below.

Scientists will use those measurements to design analysis software, or algorithms, for the upcoming Ice, Cloud and land Elevation Satellite-2 (ICESat-2) mission.

The 2014 MABEL campaign continued through July and was launched, in part, to capture melt ponds and other features of summer ice.

After nine science flights out of Fairbanks, Alaska, the ER-2 and MABEL returned to California on Aug. 1, gathering additional data along the way.

For this campaign, engineers added a new camera system to allow the team to match the MABEL measurements with a visual glimpse of the ground.

The digital camera takes a picture every 3 seconds, each frame capturing an area about 2.5 by 1.5 kilometers (1.6 by 0.9 miles).

Some of these first images downloaded were just what the MABEL team wanted to see, said Thorsten Markus, ICESat-2 project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

They want to understand how the MABEL data collected over a melt pond differs from data collected over open water, ice and more, and the images indicate there will be good measurements to analyze.

From the ER-2’s cruising altitude of 65,000 feet, the camera system snaps images of an area about 2.5 by 1.5 kilometers (1.6 by 0.9 miles). 

These melt ponds, formed by snowmelt on Alaskan glaciers, can range in size and shape. 

Credit: NASA

"We have clear open water, then we see melt ponds and then we see open water again," Markus said of a shot taken on the way to the North Pole.

"For algorithm development, this is perfect."

On a July 17 flight to the North Pole and back, the ER-2 aircraft carrying the MABEL instrument flew over fractured sea ice, dotted with melt ponds and marked by ridges formed by the dynamic ice. 

Credit: NASA

Deeper and Longer Greenland Canyons - Video

The below sea-level canyons beneath the ocean-feeding glacier cut further inland than previously estimates. Accelerated ice loss of the glacier was thought to be limited, but this finding calls into question its duration.

Credit: NASA and University of California, Irvine

New Zealand's Southern Alps glaciers reducing rapidly

Hochstetter Icefall feeding the retreating Tasman Glacier in the Southern Alps of New Zealand's Southern Island.

Credit: Dr. Huw Horgan

Historic records show Franz Josef Glacier retreated three kilometres in the last century and mathematical modeling indicates it is likely to retreat even more this century.

Other glaciers in the region, including Fox Glacier, are declining at similar rates as a result of climatic change says Dr Brian Anderson, a senior research fellow at the Antarctic Research Centre, who is supported by a Marsden Fast Start research grant.

Dr Anderson says mathematical modelling helps him, and other researchers in the team, understand how glaciers have evolved since the last ice age.

It also helps them analyse what is occurring now and predict how many glaciers in the Southern Alps will fare in the future.

Brian Anderson

"It's important to see the long term picture to really understand what's going on. That's because many of our glaciers—Fox and Franz Josef particularly—change so quickly and, apparently, so erratically.

"In the 12 years we've been carrying out this study, we've seen them rapidly retreat and then rapidly advance."

"It's not until we look back over the past century that we see an overall pattern of retreat emerging," says Dr Anderson.

"Looking ahead, we are likely to see warmer and wetter weather, which means Franz Josef and Fox glaciers will retreat a lot—our best estimate is that they will be seven or eight kilometres shorter than present by 2100."

The research findings are being collated and published as part of the Antarctic Research Centre's glacier monitoring project which also involves Dr Ruzica Dadic, Dr Huw Horgan and Associate Professor Andrew Mackintosh.

Together, the researchers are observing and measuring three glaciers—the well-known Franz Josef and Tasman glaciers and the lesser-known Brewster Glacier.

Nicolas Cullen

Other collaborators on the Brewster Glacier project are Dr Nicolas Cullen at the University of Otago and Dr Andrew Lorrey at NIWA.

The data gathered is contributing to the University of Zurich's World Glacier Monitoring Service.

Dr Anderson says: "Already we are seeing issues at Franz Josef Glacier, where walking access has not been possible for more than a year, and tourists are now being flown onto the ice."

"These are the kinds of things being predicted to happen around the world as glaciers decline and temperatures continue to warm," he says.

Earlier this year, Dr Anderson says a 70-metre chunk of ice broke off the terminal face of Tasman glacier, releasing an estimated seven million cubic metres of ice into Tasman Lake.

"Tasman is undergoing rapid decline right now, with large chunks breaking off and falling into Tasman Lake.

We are using time-lapse photography to capture these 'calving' events as they happen and gather valuable information on ice loss and glacier behaviour at the same time."

NASA ISS Image: Two glaciers in Bernese Alps, Switzerland

A NASA ISS image of two glaciers in Bernese Alps, Switzerland.

ESA ENVISAT Image: Spitrsbergen, Norway's Glacier island

Spitsbergen, Norway’s largest island, is pictured in this image, acquired on 6 September 2011 by Envisat’s Advanced Synthetic Aperture Radar (ASAR). 

Bordered by the Arctic Ocean to its north and the Greenland Sea to its west, Spitsbergen is the largest and only permanently populated island of the Svalbard archipelago.

Credits: ESA

Bordered by the Arctic Ocean to its north and the Greenland Sea to its west, Spitsbergen is the largest and only permanently populated island of the Svalbard archipelago.

The island has many glaciers, mountains and fjords – long inlets created by glacial activity.

Because of its high latitude, average summer temperatures are between 4 °C and 6 °C, while winters drop to around −20 °C. The North Atlantic Current, however, gives Spitsbergen significantly higher temperatures than other places at the same latitude.

Arctic foxes, reindeer and polar bears roam the land here. The surrounding waters are home to whales, dolphins and walruses.

This image was acquired on 6 September by Envisat’s Advanced Synthetic Aperture Radar. 

Pluto's icy exterior may conceal an ocean

PLUTO could hide a liquid ocean beneath its icy shell. Indeed, other bodies on the solar system's frigid fringe could also harbour subsurface oceans, and these could provide the conditions to sustain life.

Temperatures on Pluto's surface hover around -230 °C, but researchers have long wondered whether the dwarf planet might boast enough internal heat to sustain a liquid ocean under its icy exterior.

Now Guillaume Robuchon and Francis Nimmo at the University of California, Santa Cruz, say there is a good chance it does. They calculate that an ocean depends on two things: the amount of radioactive potassium in Pluto's rocky core, and the sloshiness of the ice that covers it.

Density measurements suggest a rocky core fills 40 per cent of the dwarf planet's volume. If the core contains potassium at a concentration of 75 parts per billion, its decay could produce enough heat to melt some of the overlying ice, which is made of a mixture of nitrogen and water.

It should have at least that much potassium and probably more, says William McKinnon at Washington University in St Louis, Missouri. He points out that Earth, which probably formed with less of the volatile element due to its closer distance to the sun, has 10 times that concentration in its core.

But merely having a source of heat is not enough to maintain a long-lived ocean. Heat from the core will trigger convection in the surrounding ice, and if the ice churns too quickly, the heat will simply escape into space before it can do much melting.

If it flows substantially more slowly than Antarctic glaciers on Earth, however, then the top 165 kilometres of ice could provide enough insulation for a liquid ocean of the same depth to exist below, the team calculates (Icarus, DOI: 10.1016/j.icarus.2011.08.015).

The viscosity of the ice depends on the size of individual ice particles, with smaller grains flowing more easily. There is no way to measure this from Earth, but Pluto's shape could reveal evidence of an ocean, the team says. 

Pluto's spin is slowing down due to tugs from its large moon Charon. Fast-spinning objects bulge out at their equator, but a soft interior would allow the world to relax into more of a sphere as its spin slows down. NASA's New Horizons probe will image the dwarf planet's shape when it flies past in 2015.

Other distant icy bodies might also have oceans, which could mean that the outer solar system is potentially ripe for life. "It's very exciting to think that these dwarf planets could have astrobiological potential," says New Horizons lead scientist Alan Stern.

Glacier Bleeding

What looks like blood gushes from a glacier in the McMurdo Dry Valleys in Antarctica.

The five-storey, red waterfall known as the Blood Falls got its name after explorer and geologist Griffith Taylor stumbled across it in 1911 and thought it resembled blood pouring from a wound. Scientists have found that the natural phenomenon occurs when iron oxide, trapped deep beneath the glacier in a hidden lake, reacts with microbes in the water.

Picture: CATERS NEWS

Mammoth iceberg could alter ocean circulation: study

Mammoth iceberg could alter ocean circulation: study

An iceberg the size of Luxembourg knocked loose from the Antarctic continent earlier this month could disrupt the ocean currents driving weather patterns around the globe, researchers said Thursday.

While the impact would not be felt for decades or longer, a slowdown in the production of colder, dense water could result in less temperate winters in the north Atlantic, they said.

The 2550 square-kilometre (985 square-mile) block broke off on February 12 or 13 from the Mertz Glacier Tongue, a 160-kilometer spit of floating ice protruding into the Southern Ocean from East Antarctica due south of Melbourne, researchers said.

Some 400 metres (1300 feet) thick, the iceberg could fill Sydney Harbour more than 100 times over.

It could also disturb the area's exceptionally rich biodiversity, including a major colony of emperor penguins near Dumont d'Urville, site of a French scientific station, according to the scientists.

"The ice tongue was almost broken already. It was hanging like a loose tooth," said Benoit Legresy, a French glaciologist who has been monitoring the Metz Glacier via satellite images and on the ground for a decade in cooperation with Australian scientists.

The billion-tonne mass was dislodged by another, older iceberg, known as B9B, which split off in 1987.

Jammed against the Antarctic continent for more than 20 years, B9B smashed into the Metz tongue like a slow-motion battering ram after it began to drift.

Both natural cycles and manmade climate change contribute to the collapse ice shelves and glaciers.

Tide and ocean currents constantly beat against exposed areas, while longer summers and rising temperatures also take a toll.

"Obviously when there is warmer water, these ice tongues will become more fragile," said Legresy, who works at the Laboratory for Geophysics and Oceanographic Space Research in Toulouse, southern France.