NASA Aqua Image: Bering Sea Teeming with Ice

For most of the winter of 2011–2012, the Bering Sea has been choking with sea ice.

Though ice obviously forms there every year, the extent of the ice cover has been unusually widespread this season.

In fact, the past several months have included the second highest ice extent in the satellite record for the Bering Sea region, according to the National Snow and Ice Data Center (NSIDC).

The natural-colour image above shows the Bering Sea and the coasts of Alaska and northeastern Russia on March 19, 2012.

The image was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite. Black lines mark the coastlines, many of which have ice shelves or frozen bays extending beyond their land borders.

NSIDC reported that ice extent in the Bering Sea for January was 562,000 square kilometers, at least 104,600 square kilometers above the 1979 to 2000 average. Though numbers were not released for February, the pattern persisted through to March 2012.

The accumulation of ice this season has largely been fueled by persistent northerly winds blowing from the Arctic Ocean across the Strait.

Local weather has been dominated this winter by a low-pressure system—with its counterclockwise circulation—that has brought extensive moisture from the south to coastal and interior Alaska and cold winds down across the sea to the west.

Those winds have pushed ice toward the narrow, shallow strait, where it piles up. Beyond the narrows, those same winds also push cold air and cold surface waters to lower latitudes, allowing the ice to grow farther south than usual.

As of March 16, National Weather Service forecasters noted that all of the ice cover in the Bering Sea was first year ice, much of it new and thin.

The widespread and persistent ice cover in the Bering Sea has posed significant problems for fisherman and for supply ships in the region.

The weather driving the ice has also brought extreme snowfall events to many parts of Alaska this winter.

The Bering stands in stark contrast to the rest of the Arctic ice cap, where sea ice extent was below average in both January and February.

Ice cover was down drastically on the Atlantic Ocean side of the Arctic, including the Kara, Barents, and Laptev Seas, where ice-free waters were 4 to 8 degrees Celsius (7 to 14 degrees Fahrenheit) above the norm.

Jet engine icing research tackles dangerous flight problem

Credit: NASA

Technicians install water sprayers in the jet engine icing test chamber at Cleveland's NASA Glenn Research Center. The sprayers will produce tiny ice crystals that can clog or damage engines.

On a stormy July evening in 2004, more than five miles above the South China Sea, the engines powering a large passenger jet en route to Taiwan suddenly failed.

A simultaneous engine shutdown on a large, modern aircraft is almost unheard of.

After a harrowing 75 seconds, the pilots managed to restart them, and the jet landed at the Taipei airport without further problems. But the incident set off alarms in the aviation community.

Minutes before its engines quit, the jet had been skirting thunderstorms spawned by a distant typhoon.

Investigators first thought the storms' powerful updrafts had pulled rain high into the atmosphere, temporarily smothering the engines when they sucked in gouts of water instead of air.

The jet's pilots had seen and heard droplets hitting the windshield, bolstering the rain theory but the jet's radar sweeps were clear, with no echoes from rain and the temperature at the altitude where the trouble began was a frigid minus-44 degrees, far too cold for liquid water.

Researchers eventually concluded the engines must have been choked by tiny ice crystals as small as flour grains, a dangerous, unexpected phenomenon that aviation officials urgently want to learn more about so they can lessen its risk.

Much of that work will take place at Cleveland's NASA Glenn Research Center, where engineers are readying a unique test chamber capable of mimicking the odd weather conditions that threatened the Taipei-bound jet, and have caused more than 150 other in-flight incidents.

"These things are happening pretty frequently, like one incident every month or so," said Glenn project manager Ron Colantonio. "NASA is working with the aviation community to understand what's causing the problem and how to mitigate it."

Glenn officials recently unveiled the silvery, boxcar-sized engine icing tunnel during a visit by NASA administrator Charles Bolden.

Glenn engineers previously had used the tunnel for other types of jet engine tests. With $15 million in Recovery Act and NASA money, they've retrofitted it with water sprayers that will produce the minute ice crystals believed to be causing the engine problems.

Sensors will track the performance of jet engines mounted on a frame in the icy air stream.

Aviation safety experts have long recognized the danger from ice buildup on wings and other external aircraft surfaces.

The hazard is caused by super-cooled liquid water freezing on contact, disrupting smooth airflow and hampering lift.

For decades engineers in Glenn's Icing Branch have led international efforts to develop better ice forecasting methods, icing sensors, anti-icing aircraft designs, and improved pilot training.

Read more on this article here: 

BAS Fly-through of Antarctica's Gamburtsev 'ghost mountains'

Click on the Image to visit BBC website and activate the Animation.

Scientists think they can now explain the existence of what are perhaps Earth's most extraordinary mountains.

The Gamburtsevs are the size of the European Alps and yet are totally buried beneath the Antarctic ice.

A geophysical survey of the range was conducted in 2008/9. This allowed researchers to assess the mountains' origin.

In this video, Fausto Ferraccioli from the British Antarctic Survey takes us on a virtual fly-through of the Gamburtsevs.

Animation courtesy of the British Antarctic Survey.

NASA NPP: New Type of Earth-Observing Satellite for Launch

NPP inside a clean room at Vandenberg Air Force Base in California. Credit: NASA/30th Communications Squadron, VAFB.

NASA is planning an Oct. 27 launch of the first Earth-observing satellite to measure both global climate changes and key weather variables.

The National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) is the first mission designed to collect critical data to improve weather forecasts in the short-term and increase our understanding of long-term climate change.

NPP continues observations of Earth from space that NASA has pioneered for more than 40 years.

NPP's five science instruments, including four new state-of-the-art sensors, will provide scientists with data to extend more than 30 key long-term datasets.

These records, which range from the ozone layer and land cover to atmospheric temperatures and ice cover, are critical for global change science.

"NPP's observations of a wide range of interconnected Earth properties and processes will give us the big picture of how our planet changes," said Jim Gleason, NPP project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.

"That will help us improve our computer models that predict future environmental conditions. Better predictions will let us make better decisions, whether it is as simple as taking an umbrella to work today or as complex as responding to a changing climate."

NPP serves as a bridge between NASA's Earth Observing System of satellites and the planned Joint Polar Satellite System (JPSS), which will collect climate and weather data. JPSS will be developed by NASA for the National Oceanic and Atmospheric Administration (NOAA).

NOAA meteorologists will incorporate NPP data into their weather prediction models to produce forecasts and warnings that will help emergency responders anticipate, monitor and react to many types of natural disasters.

"The timing of the NPP launch could hardly be more appropriate," said Louis W. Uccellini, director of NOAA's National Centers for Environmental Prediction in Camp Springs, Md. "With the many billion dollar weather disasters in 2011, NPP data is critical for accurate weather forecasts into the future."

A Delta II rocket will carry NPP into an orbit 512 miles above Earth's surface. Roughly the size of a mini-van, the spacecraft will orbit Earth's poles about 14 times a day. It will transmit data once each orbit to a ground station in Svalbard, Norway, and to direct broadcast receivers around the world.

NPP is set to launch from Space Launch Complex 2 at Vandenberg Air Force Base in California on Oct. 27. The launch window extends from 5:48 a.m. to 5:57 a.m. EDT.

The launch recently was delayed two days due to the repair of the Delta II's hydraulic system. The NPP spacecraft is scheduled to be transported to the launch pad for attachment to the Delta II on Oct. 12.

NASA Leads Study of Unprecedented Arctic Ozone Loss

Left: Ozone in Earth's stratosphere at an altitude of approximately 12 miles (20 kilometers) in mid-March 2011, near the peak of the 2011 Arctic ozone loss. 

Right: chlorine monoxide – the primary agent of chemical ozone destruction in the cold polar lower stratosphere – for the same day and altitude.

Image credit: NASA/JPL-Caltech

A NASA-led study has documented an unprecedented depletion of Earth's protective ozone layer above the Arctic last winter and spring caused by an unusually prolonged period of extremely low temperatures in the stratosphere.

The study, published online Sunday, Oct. 2, in the journal Nature, finds the amount of ozone destroyed in the Arctic in 2011 was comparable to that seen in some years in the Antarctic, where an ozone "hole" has formed each spring since the mid-1980s.

The stratospheric ozone layer, extending from about 10 to 20 miles (15 to 35 kilometers) above the surface, protects life on Earth from the sun's harmful ultraviolet rays.

The Antarctic ozone hole forms when extremely cold conditions, common in the winter Antarctic stratosphere, trigger reactions that convert atmospheric chlorine from human-produced chemicals into forms that destroy ozone.

The same ozone-loss processes occur each winter in the Arctic. However, the generally warmer stratospheric conditions there limit the area affected and the time frame during which the chemical reactions occur, resulting in far less ozone loss in most years in the Arctic than in the Antarctic.



To investigate the 2011 Arctic ozone loss, scientists from 19 institutions in nine countries (United States, Germany, The Netherlands, Canada, Russia, Finland, Denmark, Japan and Spain) analyzed a comprehensive set of measurements.

These included daily global observations of trace gases and clouds from NASA's Aura and CALIPSO spacecraft; ozone measured by instrumented balloons; meteorological data and atmospheric models.

The scientists found that at some altitudes, the cold period in the Arctic lasted more than 30 days longer in 2011 than in any previously studied Arctic winter, leading to the unprecedented ozone loss. Further studies are needed to determine what factors caused the cold period to last so long.

"Day-to-day temperatures in the 2010-11 Arctic winter did not reach lower values than in previous cold Arctic winters," said lead author Gloria Manney of NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the New Mexico Institute of Mining and Technology in Socorro.

"The difference from previous winters is that temperatures were low enough to produce ozone-destroying forms of chlorine for a much longer time. This implies that if winter Arctic stratospheric temperatures drop just slightly in the future, for example as a result of climate change, then severe Arctic ozone loss may occur more frequently."

NASA Radar Finds Ice Deposits at Moon's North Pole

NASA Radar Finds Ice Deposits at Moon's North Pole

Using data from a NASA radar that flew aboard India's Chandrayaan-1 spacecraft, scientists have detected ice deposits near the moon's north pole.

NASA's Mini-SAR instrument, a lightweight, synthetic aperture radar, found more than 40 small craters with water ice.

The craters range in size from 1 to 9 miles (2 to15 km) in diameter. Although the total amount of ice depends on its thickness in each crater, it's estimated there could be at least 1.3 trillion pounds (600 million metric tons) of water ice.

The Mini-SAR has imaged many of the permanently shadowed regions that exist at both poles of the Moons. These dark areas are extremely cold and it has been hypothesized that volatile material, including water ice, could be present in quantity here. The main science object of the Mini-SAR experiment is to map and characterize any deposits that exist.

Mini-SAR is a lightweight (less than 10 kg) imaging radar. It uses the polarisation properties of reflected radio waves to characterise surface properties. Mini-SAR sends pulses of radar that are left-circular polarised.

Typical planetary surfaces reverse the polarisation during the reflection of radio waves, so that normal echoes from Mini-SAR are right circular polarised. The ratio of received power in the same sense transmitted (left circular) to the opposite sense (right circular) is called the circular polarisation ratio (CPR).

Most of the Moon has low CPR, meaning that the reversal of polarisation is the norm, but some targets have high CPR. These include very rough, fresh surfaces (such as a young, fresh crater) and ice, which is transparent to radio energy and multiply scatters the pulses, leading to an enhancement in same sense reflections and hence, high CPR.

CPR is not uniquely diagnostic of either roughness or ice; the science team must take into account the environment of the occurrences of high CPR signal to interpret its cause.