Wednesday, December 30, 2009

Researchers sneak a look under Ice Sheets for Clues on Climate Change

A team of National Science Foundation (NSF)-funded researchers wants to look under the ice sheets in Greenland and Antarctica to see if they are sitting on bedrock or water.

Together, the ice sheets in Greenland and Antarctica contain enough freshwater to raise global sea level by more than 190 feet if they were to melt entirely and transfer to the world's oceans. A complete collapse of these vast reservoirs of ice is unlikely in the near future. However, recent observations have raised the real possibility that the contribution of the great ice sheets to global sea level rise over the next century may be greater than current models suggest.

Rising sea levels can adversely affect communities near the shoreline, especially in third world countries, and they are believed to be an indicator of global climate change.

Until recently, the prevailing view was that these large ice masses moved sluggishly, and discharged ice from their interior to the world's oceans at a slow, orderly, and predictable rate. This view was increasingly challenged as observations of rapidly changing outlet glaciers and ice streams became available. For example, the Jakobshavn Isbræ glacier in Western Greenland more than doubled its speed from around 3.72 miles per year in 1992, to nearly 8.68 miles per year in 2003.

Because of the immense size and complexity of these ice sheets, scientists need data from satellite and airborne platforms, combined with ground-based measurements and observations, to accurately assess their mass and composition.

Gogineni and his colleagues have adapted synthetic aperture radar technology, developed for remote sensing in space, to the ice environment. By increasing its sensitivity and integrating the technology with aircraft instrumentation, the researchers report the advanced radar system can image large areas of ice-bed interfaces located below an ice layer more than two miles thick. The ability to generate radar images of large areas of ice is a big improvement over past studies that have sought to understand what is happening beneath the ice sheets.

According to Gogineni, data from remote sensing satellites, combined with images generated by this radar sensor, may revolutionize the study of polar ice sheets. "We have demonstrated we can map the layers of ice all the way down to the ice-bed interface. The layers are like tree rings; they tell a story of climate history."

The researchers ultimately expect their data to improve existing models of the composition and movement of the ice sheets. Their findings may cause some traditional explanations about the ice sheets to be reconsidered. For example, traditional models have assumed the ice sheets were frozen to the underlying bed material. Early data indicate the presence of water beneath the ice in many areas. That finding could be significant because a lot of water predicts a lot of future ice movement, but Gogineni cautions that more work needs to be done before they can draw any conclusions.

Tuesday, December 29, 2009

NASA Uses Twin method to increase New Tank Dome Technology

NASA has partnered with Lockheed Martin Space Systems in Denver, Colo., and MT Aerospace in Augsburg, Germany, to successfully manufacture the first full-scale friction stir welded and spun formed tank dome designed for use in large liquid propellant tanks.

The NASA and Lockheed Martin team traveled to Germany to witness the first successful aerospace application of two separate manufacturing processes: friction stir welding, a solid-state joining process, and spin forming, a metal working process used to form symmetric parts.

The twin processes were used by MT Aerospace to produce an 18-foot-diameter tank dome using high-strength 2195 aluminum-lithium. The diameter of this development dome matches the tank dimensions of the upper stage of the ARES I launch vehicle under development by NASA, as well as the central stage of the European Ariane V launcher.

The concave net shape spin forming process, patented by MT Aerospace, drastically simplifies the manufacturing of large tank domes and reduces cost by eliminating manufacturing steps, such as machining and assembly welding, that are required when manufacturing traditional gore panel - a pie-shaped section of the tank dome --construction domes.

The spherical tank dome was manufactured from a flat plate "blank" made of the 2195 alloy. The blank was constructed by friction stir welding together two commercial off-the-shelf plates in order to produce a large starting blank, reducing the cost of raw materials. The welded plate blank was then spun formed to create the single-piece tank dome.

This is the first time this combination of twin manufacturing processes has been successfully applied to produce a full-scale 2195 aluminum-lithium dome.
Two additional, full-scale development tank domes are scheduled for manufacture and testing in coming months as part of the joint, two-year technology demonstration program.

Sunday, December 27, 2009

Marine Scientists Discover Deepest underwater Erupting Volcano

The volcanic eruption, discovered in May, is nearly 4,000 feet below the surface of the Pacific Ocean, in an area bounded by Fiji, Tonga and Samoa.

Imagery includes large molten lava bubbles three feet across bursting into cold seawater, glowing red vents exploding lava into the sea, and the first-observed advance of lava flows across the deep-ocean floor.

Sounds of the eruption were recorded by a hydrophone and later matched with the video footage.

Expedition scientists released the video and discussed their observations at a Dec. 17 news conference at the American Geophysical Union (AGU)'s annual fall meeting in San Francisco.

The West Mata Volcano is producing boninite lavas, believed to be among the hottest on Earth in modern times, and a type seen before only on extinct volcanoes more than one million years old.
University of Hawaii geochemist Ken Rubin believes that the active boninite eruption provides a unique opportunity to study magma formation at volcanoes, and to learn more about how Earth recycles material where one tectonic plate is subducted under another.

Water from the volcano is very acidic, with some samples collected directly above the eruption, the scientists said, as acidic as battery acid or stomach acid.

Julie Huber, a microbiologist at the Marine Biological Laboratory, found diverse microbes even in such extreme conditions.

Tim Shank, a biologist at the Woods Hole Oceanographic Institution (WHOI), found that shrimp were the only animals thriving in the acidic vent water near the eruption. Shank is analyzing shrimp DNA to determine whether they are the same species as those found at seamounts more than 3,000 miles away.

The scientists believe that 80 percent of eruptive activity on Earth takes place in the ocean, and that most volcanoes are in the deep sea.

Further study of active deep-ocean eruptions will provide a better understanding of oceanic cycles of carbon dioxide and sulfur gases, how heat and matter are transferred from the interior of the Earth to its surface, and how life adapts to some of the harshest conditions on Earth.

Tuesday, December 22, 2009

Sparkling sunlight, confirms liquid in Titan lake zone

NASA's Cassini Spacecraft has captured the first flash of sunlight reflected off a lake on Saturn's moon Titan, confirming the presence of liquid on the part of the moon dotted with many large, lake-shaped basins.

Cassini scientists had been looking for the glint, also known as a specular reflection, since the spacecraft began orbiting Saturn in 2004. But Titan's northern hemisphere, which has more lakes than the southern hemisphere, has been veiled in winter darkness. The sun only began to directly illuminate the northern lakes recently as it approached the equinox of August 2009, the start of spring in the northern hemisphere. Titan's hazy atmosphere also blocked out reflections of sunlight in most wavelengths.

In 2008, Cassini scientists using infrared data confirmed the presence of liquid in Ontario Lacus, the largest lake in Titan's southern hemisphere. But they were still looking for the smoking gun to confirm liquid in the northern hemisphere, where lakes are also larger.

Katrin Stephan, of the German Aerospace Center (DLR) in Berlin, an associate member of the Cassini visual and infrared mapping spectrometer team, was processing the initial image and was the first to see the glint on July 10th.

Team members at the University of Arizona, Tucson, processed the image further, and scientists were able to compare the new image to radar and near-infrared-light images acquired from 2006 to 2008.

They were able to correlate the reflection to the southern shoreline of a lake called Kraken Mare. The sprawling Kraken Mare covers about 400,000 square kilometers (150,000 square miles), an area larger than the Caspian Sea, the largest lake on Earth. It is located around 71 degrees north latitude and 337 degrees west latitude.

The finding shows that the shoreline of Kraken Mare has been stable over the last three years and that Titan has an ongoing hydrological cycle that brings liquids to the surface, said Ralf Jaumann, a visual and infrared mapping spectrometer team member who leads the scientists at the DLR who work on Cassini. Of course, in this case, the liquid in the hydrological cycle is methane rather than water, as it is on Earth.

Sunday, December 20, 2009

Know more about Mercury in Fish and Shellfish

Fish and shellfish are an important part of a healthy diet. Fish and shellfish contain high- quality protein and other essential nutrients, are low in saturated fat, and contain omega-3 fatty acids. A well-balanced diet that includes a variety of fish and shellfish can contribute to heart health and children's proper growth and development. So, women and young children in particular should include fish or shellfish in their diets due to the many nutritional benefits.

However, nearly all fish and shellfish contain traces of mercury. For most people, the risk from mercury by eating fish and shellfish is not a health concern. Yet, some fish and shellfish contain higher levels of mercury that may harm an unborn baby or young child's developing nervous system. The risks from mercury in fish and shellfish depend on the amount of fish and shellfish eaten and the levels of mercury in the fish and shellfish. Therefore, the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) are advising women who may become pregnant, pregnant women, nursing mothers, and young children to avoid some types of fish and eat fish and shellfish that are lower in mercury.

By following these three recommendations for selecting and eating fish or shellfish, women and young children will receive the benefits of eating fish and shellfish and be confident that they have reduced their exposure to the harmful effects of mercury.

1. Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.
2. Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury.
o Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
o Another commonly eaten fish, albacore ("white") tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.
3. Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas.
If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.
Follow these same recommendations when feeding fish and shellfish to your young child, but serve smaller portions.

Friday, December 18, 2009

Earth’s "Third Pole" under threat

Black Carbon Deposits on Himalayan Ice Threaten Earth’s "Third Pole"
Black soot deposited on Tibetan glaciers has contributed significantly to the retreat of the world’s largest non-polar ice masses, according to new research by scientists from NASA and the Chinese Academy of Sciences. Soot absorbs incoming solar radiation and can speed glacial melting when deposited on snow in sufficient quantities.

Temperatures on the Tibetan Plateau -- sometimes called Earth's "third pole" -- have warmed by 0.3°C (0.5°F) per decade over the past 30 years, about twice the rate of observed global temperature increases. New field research and ongoing quantitative modeling suggests that soot's warming influence on Tibetan glaciers could rival that of greenhouse gases.

Since melt water from Tibetan glaciers replenishes many of Asia’s major rivers -- including the Indus, Ganges, Yellow, and Brahmaputra -- such losses could have a profound impact on the billion people who rely on the rivers for fresh water. While rain and snow would still help replenish Asian rivers in the absence of glaciers, the change could hamper efforts to manage seasonal water resources by altering when fresh water supplies are available in areas already prone to water shortages.

Most soot in the region comes from diesel engines, coal-fired power plants, and outdoor cooking stoves. Many industrial processes produce both black carbon and organic carbon, but often in different proportions. Burning diesel fuel produces mainly black carbon, for example, while burning wood produces mainly organic carbon. Since black carbon is darker and absorbs more radiation, it’s thought to have a stronger warming effect than organic carbon.

Tuesday, December 15, 2009

NASA's AIM Satellite and Models helps in Unlocking the Secrets of Mysterious Night Shining Clouds

NASA's Aeronomy of Ice in the Mesosphere (AIM) satellite has captured five complete polar seasons of noctilucent (NLC) or "night-shining" clouds with an unprecedented horizontal resolution of 3 miles by 3 miles. Results show that the cloud season turns on and off like a "geophysical light bulb" and they reveal evidence that high altitude mesospheric "weather" may follow similar patterns as our ever-changing weather near the Earth's surface. These findings were unveiled today at the Fall Meeting of the American Geophysical Union today in San Francisco.

The AIM measurements have provided the first comprehensive global-scale view of the complex life cycle of these clouds, also called Polar Mesospheric Clouds (PMCs), over three entire Northern Hemisphere and two Southern Hemisphere seasons revealing more about their formation, frequency and brightness and why they appear to be occurring at lower latitudes than ever before.

"The AIM findings have altered our previous understanding of why PMCs form and vary," stated AIM principal investigator Dr. James Russell III of Hampton University in Hampton, Va. "We have captured the brightest clouds ever observed and they display large variations in size and structure signifying a great sensitivity to the environment in which the clouds form. The cloud season abruptly turns on and off going from no clouds to near complete coverage in a matter of days with the reverse pattern occurring at the season end."

These bright "night-shining" clouds, which form 50 miles above Earth's surface, are seen by the spacecraft's instruments, starting in late May and lasting until late August in the north and from late November to late February in the south. The AIM satellite reports daily observations of the clouds at all longitudes and over a broad latitude range extending from 60 to 85 degrees in both hemispheres.

The clouds usually form at high latitudes during the summer of each hemisphere. They are made of ice crystals formed when water vapor condenses onto dust particles in the brutal cold of this region, at temperatures around minus 210 to minus 235 degrees Fahrenheit. They are called "night shining" clouds by observers on the ground because their high altitude allows them to continue reflecting sunlight after the sun has set below the horizon. They form a spectacular silvery blue display visible well into the night time.

Sophisticated multidimensional models have also advanced significantly in the last few years and together with AIM and other space and ground-based data have led to important advances in understanding these unusual and provocative clouds. The satellite data has shown that:

1. Temperature appears to control season onset, variability during the season, and season end. Water vapor is surely important but the role it plays in NLC variability is only now becoming more understood,

2. Large scale planetary waves in the Earth's upper atmosphere cause NLCs to vary globally, while shorter scale gravity waves cause the clouds to disappear regionally;

3. There is coupling between the summer and winter hemispheres: when temperature changes in the winter hemisphere, NLCs change correspondingly in the opposite hemisphere.

Computer models that include detailed physics of the clouds and couple the upper atmosphere environment where they occur with the lower regions of the atmosphere are being used to study the reasons the NLCs form and the causes for their variability. These models are able to reproduce many of the features found by AIM. Validation of the results using AIM and other data will help determine the underlying causes of the observed changes in NLCs.

Monday, December 14, 2009

Fiery lightshow in Earth's upper atmosphere

The Perseid meteor shower lights up the sky in August. Star-gazers can expect a similar view during December's Geminid meteor shower, which will be visible in the late evening hours of December 13 and 14.

Bundle up and get ready to watch a fiery lightshow stirred up by dead comets in Earth's upper atmosphere during the cold of winter in the dead of night. The annual Geminid meteor shower is expected to peak mid-December. Considered one of the more reliable showers by those in the meteor-watching business, the Geminids almost always put on a great show.

"You could expect to see over 100 meteors per hour during the peak viewing," said Don Yeomans, manager of NASA's Near-Earth Object Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "During the late evening hours of December 13, look for streaks of light radiating from a point near the star Castor in the constellation of Gemini, which will be high above the eastern horizon for mid-northern latitudes."

While a sign of the zodiac may have provided the name for the meteor shower, scientists have established the source as something more tangible. "We do know that the origin of the Geminids is a Near-Earth object called 3200 Phaeton," said Yeomans. "It is probably the remains of a comet that has burned off its ices after eons looping throughout the solar system. Phaeton has a trail of pebble and dust-sized debris that stream out behind it. Once every mid-December, Earth's orbit carries it into this stream of debris."

Since all other meteors showers are due to the sand-sized particles from active comets, it seems reasonable to assume that Phaeton is, or at least was, a comet. However, Phaeton has shown no cometary activity, so it is classified as an asteroid - the only asteroid to have an associated meteor shower.

"It is important to note that the orbits of Earth and Phaethon itself will not intersect," added Yeomans. "There is no chance the two will meet. But the result of our planet flying through its debris field is an opportunity for science and the chance to see Mother Nature at her best."

Wednesday, December 09, 2009

United States faces Abrupt Climate Change

The United States faces the potential for abrupt climate change in the 21st century that could pose clear risks to society in terms of our ability to adapt.

These changes in climate and related environmental systems can occur over decades or less, persist for decades more, and cause substantial disruptions to human and natural systems.

A 2008 report from the U.S. Global Change Research Program (USGCRP) / Climate Change Science Program (CCSP), Abrupt Climate Change, drew the following conclusions about the prospects for abrupt changes over the next century:

• Climate model simulations and observations suggest that rapid and sustained September arctic sea ice loss is likely in the 21st century.
• The southwestern United States may be beginning an abrupt period of increased drought.
• It is very likely that the northward flow of warm water in the upper layers of the Atlantic Ocean, which has an important impact on the global climate system, will decrease by approximately 25–30 percent. However, it is very unlikely that this circulation will collapse or that the weakening will occur abruptly during the 21st century and beyond.
• An abrupt change in sea level is possible, but predictions are highly uncertain due to shortcomings in existing climate models.
• There is unlikely to be an abrupt release of methane, a powerful greenhouse gas, to the atmosphere from deposits in the earth. However, it is very likely that the pace of methane emissions will increase.

A 2009 report from the USGCRP/CCSP titled Thresholds of Climate Change in Ecosystems examined abrupt changes in biological systems. One example cited in the report in which a biological threshold has already been crossed is the relatively sudden outbreak of spruce bark beetles that has occurred across parts of the western United States. This has been caused in part by the increase in winter temperatures above a threshold that has greatly enhanced the over-winter survival of the beetles. Another example of an ecosystem threshold is the coral bleaching that occurs above certain levels of ocean acidity and temperature.

According to this report, in order to better understand and prepare for ecological threshold crossings and their consequences, it is essential to increase the resilience of ecosystems and thus to slow or prevent the crossing of thresholds; to identify early warning signals of impending threshold changes; and to employ adaptive management strategies to deal with new conditions and new combinations of species.

Monday, December 07, 2009

Dangerous Impact on Coral Reefs of Northwestern Hawaiian Islands

Results of a new study shed light on how threats to the worlds endangered coral reef ecosystems can be more effectively managed.
In the current issue of the journal Coral Reefs, authors Kimberly Selkoe and Benjamin Halpern, both of the National Center for Ecological Analysis and Synthesis (NCEAS) at the University of California at Santa Barbara, explain how maps of the Northwestern Hawaiian Islands (NWHI)--a vast area stretching across more than 1,200 miles of Pacific Ocean--can be used to make informed decisions about protecting the world's fragile coral reefs.
"Our maps of cumulative human impacts are a powerful tool for synthesizing and visualizing the state of the oceans," said Selkoe, who is also affiliated with Hawaii Institute of Marine Biology at the University of Hawaii.
"The maps can aid in zoning uses of the oceans in an informed way that maximizes commercial and societal benefits, while minimizing further cumulative impact."
President George W. Bush declared the Northwestern Hawaiian Islands a National Monument in 2006, "in part because it is one of the last places in the oceans that have not been heavily altered by human activities," said Halpern.
"Despite the islands' extreme isolation, however, humans are already significantly impacting this area," he said. "Many of the key threats, such as those associated with climate change, are not mitigated with Monument designation."
The study was designed to help natural resource managers make decisions on issues such as surveillance priorities, granting of permits for use, and selection of areas to monitor for climate change effects.
"The Papahânaumokuâkea Marine National Monument is a crown jewel in the national and international array of marine protected areas, designed to preserve the ecosystems of these isolated islands," said Phillip Taylor of the National Science Foundation (NSF)'s Division of Ocean Sciences.
"This study is an important effort to assess and predict human effects on the oceans," Taylor said. "It shows how far-reaching human influences are, and will serve as a baseline in efforts to prevent and mitigate future harm."
The authors studied 14 threats specific to NWHI. The threats, all generated by humans, included invasive species, bottom fishing, lobster trap fishing, ship-based pollution, ship strike risks, marine debris, research diving, research equipment installation and wildlife sacrifice for research.
Human-induced climate change threats were also studied, including increased ultraviolet radiation, ocean acidification, ocean temperature anomalies relevant to disease outbreaks and coral bleaching, and sea level rise.
Increased rates of coral disease due to warming ocean temperatures were found to have the highest impact, along with other climate-related threats.
"With the scientific justification provided by our study, the managers of the Monument have an opportunity to make addressing the worst threats a top priority," said Selkoe.
"By updating the map of cumulative impacts through time, success of management plans in reducing impacts can be measured, and permits for new uses can be evaluated in the context of how they add to these impacts."

Tuesday, December 01, 2009

Coral Reefs are Undersea Treasure, We need to protect them

Healthy coral reefs are beautiful, awe-inspiring ecosystems — owing to the enormously rich biological diversity found within and above them. These sublime environments attract human visitors like bees to honey.

Economic and environmental services: they offer an abundant supply of seafood and protect the shoreline from waves, storms, and floods.

Priceless Resources in Peril
Unfortunately, a brief look at the news explains the grim story about coral reefs. Rapid warming, accelerating pollution, and destructive fishing practices are decimating coral reefs faster than they can adapt to survive.

Just as damaged and degraded coral reefs lose their appeal to divers and snorkelers, they also fail to provide the sustenance and coastal protection on which we depend. It’s clear that successful coral reef conservation efforts benefit us as well as the reefs.

Saving the Reefs Starts with the Shore
Sediment runoff and surges in algal cover caused by nutrient pollution from land are among the main causes of injury to coral reefs. Identifying and controlling pollution on land has direct benefits for coral reefs as well as water users within the region.

Fishing for Tomorrow
Overexploitation of key marine wildlife species, which are essential for balancing the ecosystem, is severely damaging coral reefs. Sharks and lobsters are prime examples. Some industrialized fishing techniques and certain types of gear also are causing major damage to coral structures.
Minimizing the destructive effects of over fishing, and achieving responsible, ecosystem-based stewardship of reef fisheries pays lasting dividends to healthy coral reefs and to those who make a living from the sea.

Building 'Bridges' to Help Corals Survive Climate Change
Corals face a major threat from climate change in the form of warmer and more acidic oceans, which cause mass bleaching and slow the growth of coral skeletons. Reducing greenhouse gases is essential to corals’ long-term survival. In the meantime, boosting the resilience of coral reef ecosystems and reducing local stresses are bridge solutions until the overarching climate threat is reduced.
Think Reef
Whether you live one mile or one thousand miles from a coral reef, your actions affect the reefs’ future — and the reefs’ future affects yours. There are a host of reef-conserving tips we can all make use of in our everyday lives that can also benefit for our own pocketbooks:

• Don’t use chemically enhanced pesticides and fertilizers. These products ultimately end up in the ocean, via a stream, lake, estuary, or a wetland.
• Conserve water. The less you use, the less runoff and wastewater pollute the oceans.
• Use more efficient electrical appliances and lighting, and keep them turned off when not necessary. You’ll reduce waste, save money, and lessen your climate change impact.