Posts Tagged "nasa"

Roundup: Grounding Lines, Fault Lines and Algae-filled Pits

Posted by on Sep 28, 2015 in All Posts, Featured Posts, News | 0 comments

Roundup: Grounding Lines, Fault Lines and Algae-filled Pits

Spread the News:ShareNASA reports on the Hidden Melting of Greenland’s Glaciers “What’s causing this ‘big thaw’? Rignot’s team found that Greenland’s glaciers flowing into the ocean are grounded deeper below sea level than previously measured. This means that the warm ocean currents at depth can sweep across the glacier faces and erode them.“In polar regions, the upper layers of ocean water are cold and fresh,” he explains. “Cold water is less effective at melting ice. The real ocean heat is at a depth of 350-400 meters and below. This warm, salty water is of subtropical origin and melts the ice much more rapidly.” To learn more, click here. Biological interactions between Microalgae and Glacial Grazers “Glaciers are known to harbor surprisingly complex ecosystems. On their surface, distinct cylindrical holes filled with meltwater and sediments are considered as hot spots for microbial life. The present paper addresses possible biological interactions within 5 the community of prokaryotic cyanobacteria and eukaryotic microalgae (microalgae) and relations to their potential grazers, additional to their environmental controls…. We propose that, for the studied glaciers, nutrient levels related to recycling of limiting nutrients is the main factor driving variation in the community structure of microalgae and grazers.” Read more about the study here. Italy’s glaciers retreated by 40 percent: WWF “ROME: Alpine glaciers in Italy have lost an estimated 40 percent of their area over the last three decades, a recent report released by World Wildlife Fund (WWF) has said. “The situation of glaciers on the Italian side of the Alps is very worrying,” Xinhua news agency on Friday quoted Gianfranco Bologna, scientific director of WWF-Italy and co-author of the report as saying. The Hot Ice report was unveiled earlier this week, ahead of a crucial United Nations Climate Change Conference due to be held in Paris from November 30 to December 11.” Read more here.   Spread the...

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Scientists Find Nitrogen Ice Glaciers on Pluto

Posted by on Aug 13, 2015 in All Posts, Featured Posts, Images, Science | 0 comments

Scientists Find Nitrogen Ice Glaciers on Pluto

Spread the News:ShareNewly released close-up photographs from NASA’s New Horizons mission show evidence of exotic ice flow across dwarf-planet Pluto’s surface, indicating that Earth may not be the only planet with glacier-like geology. New Horizon’s Long-Range Reconnaissance Imager (LORRI) shows close-up photos of a sheet of ice that appears to have glided across Pluto’s surface in similar manner as glacier movement on Earth. On Earth, melting glaciers are often characterized by surface flows around obstacles and towards the point of deepest depression, often creating swirl-shaped surfaces. New photos from the New Horizons mission show that Pluto too exhibits this characteristic warped surface. According to Bill McKinnon, the deputy leader of New Horizons Geology, Geophysics, and Imaging team, Pluto’s frosty temperature of minus-390 degrees Fahrenheit allows these ices to move in a manner similar to those on Earth. This movement might still be continuing, scientists speculate, but it is difficult to discern from still photographs whether Pluto’s frozen ice is still flowing. The ice stems from the center of Sputnik Planum, a craterless plain lying in “the heart of the heart” of Pluto. According to NASA scientists, this plain, lying in the western half of the Tombaugh region, appears to be no more than 100 million years old, making it a relatively young surface of Pluto. This region is likely still be being shaped by geological processes. NASA’s associate administrator for the Science Mission Directorate, John Grunsfeld, told NASA that the diverse and surprising findings of the New Horizons Pluto mission have been “truly thrilling.” “We’ve only seen surfaces like this on active worlds like Earth and Mars,” said mission co-investigator John Spencer of SwRI. “I’m really smiling.” The ice that comprises the plain is primarily composed of nitrogen, although it is also carbon monoxide- and methane-rich. New Horizon’s Ralph Instrument reveals that the concentration of carbon monoxide in ice steadily increases towards the center of the heart’s “bulls-eye.” These findings call into question the very definition of “glaciers,” and whether this geological term can be applied not only to other planets, but also to different chemical compositions of ice. Glaciers, as interpreted by the National Snow and Ice Data Center, are composed of fallen snow that compresses into large, thickened ice masses over a number of years. The chemical makeup of snow differs largely from Pluto’s nitrogen-, carbon monoxide-, and methane-rich ice makeup. For now, scientists and the media seem content to use the term “glacier-like” when referring to Pluto’s newly discovered nitrogen ice flow. Through the New Horizons mission, NASA scientists have also discovered Pluto’s latitudinal planetary zones, and believe them to be caused by seasonal ice transport from the equator to the icy poles. Lending additional support to this theory, enhanced color images of the planet show that Pluto’s darkest terrains appear at the equator, while a seemingly whiter, icy expanse reigns in the northern polar region. Another region, the southern-most region of Pluto’s heart, Cthulhu Regio (one of the older, heavily-cratered regions of the planet) is also believed to be filled with newer icy deposits. The New Horizons mission has also discovered Pluto’s mountain ranges, exotic surface chemistry, and a peculiar haze surrounding the planet that extends as high as 80 miles above the planet’s surface. Scientists and the public have been delighted with and captivated by the diverse and surprising findings of the New Horizons mission. A closer view of the distant dwarf planet has provided knowledge of Pluto’s features that are both similar to Earth’s, such as these glaciers, as well as those that are vastly different. Spread the...

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PhotoFriday: NASA Views Greenland Glaciers From Above

Posted by on Jun 19, 2015 in All Posts, Featured Posts, Images | 0 comments

PhotoFriday: NASA Views Greenland Glaciers From Above

Spread the News:ShareNASA’s Operation IceBridge is finishing up its seventh annual campaign surveying Arctic ice levels. The operation has run biannual polar expeditions, one to the Arctic and the other to the Antarctic, each year since its formation in 2009. This year’s spring survey of the Arctic wrapped up on May 22. While Operation IceBridge uses advanced remote sensing technologies to measures ice levels, IceBridge scientist John Sonntag captured a few stunning shots of glacial moulins and crevassing during a Greenland expedition. Greenland Glaciers Glacial Fissures in Greenland IceBridge Moulin NASA states IceBridge’s mission is to “yield an unprecedented three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice.” Annual data collected from IceBridge also helps to provide continuous polar ice data throughout the gap in data collection during NASA’s Ice, Cloud and Land Elevation Satellite (ICESat), which has not collected data since 2010. The satellite’s successor, ICESat-2, will not begin data collection until 2017. In an article for NASA’s Earth Observatory, IceBridge project scientist Michael Studinger cited the importance of IceBridge in improving sea level rising forecasts, especially for influential annual reports such as from the Intergovernmental Panel on Climate Change (IPCC). He said, “IceBridge exists because we need to understand how much ice the Greenland and Antarctic ice sheets will contribute to sea level rise over the next couple of decades. In order to do this, we need to measure how much the ice surface elevation is changing from year to year.” You can click here to explore some of IceBridge’s data and findings. To read more about moulins, check out this GlacierHub article about moulin ice caves. Photo Friday highlights photo essays and collections from areas with glaciers. If you have photos you’d like to share, let us know in the comments, by Twitter @glacierhub or email us at glacierhub@gmail.com.  Spread the...

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Tracking Glaciers From Space: GLIMS

Posted by on Feb 11, 2015 in All Posts, Featured Posts, Images, Science | 0 comments

Tracking Glaciers From Space: GLIMS

Spread the News:ShareIn 1994, an international group of scientists came together to form GLIMS (Global Land Ice Measurements from Space), a worldwide initiative to monitor and study glaciers using satellite data. For at least one hundred years, scientists had primarily used traditional field measurements to track glacier dynamics, but field data are by necessity limited in scope, and can be expensive and laborious to obtain. The GLIMS team ultimately chose to use an imaging system called Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), jointly managed by NASA and Japan, for their glacier measurements. ASTER is installed aboard Terra, the flagship satellite of NASA’s Earth Observing System (EOS), which was launched in December 1999. ASTER data can be used to map land surface temperature, reflectance, and elevation, which allows the scientists to distinguish between glacier ice and snow and to measure changes in glacier volume. Using digital images and data provided by ASTER, GLIMS created an up-to-the-minute database of the world’s glaciers, which includes ID, name, cross-references, and analysis of the state and dynamics of individual glaciers. In August 2014, GLIMS published their findings in book form: Global Land Ice Measurements from Space compiles these glacier profiles, provides a review of analysis methodologies for measuring changes in glacier volume, and offers predictions for future glacier change as well as some interpretations of potential impacts for policymakers in the context of climate change. The GLIMS scientists provide firm evidence that glaciers are shrinking worldwide, and they believe the cause is global warming. The GLIMS book offers a basic theoretical background in glacier monitoring and mapping as well as remote sensing techniques. It also discusses measurements of glacier thinning from digital elevation models (DEMs), and calculation of surface flow velocities from satellite images. DEMs can provide specific data for every pixel in a satellite image, with a margin of error at 0.5m/year. Although cloud cover can interfere with accurate satellite data on glaciers, scientists are able to identify and discard this faulty data. As described in the book, GLIMS scientists Siri Jodha Singh Khalsa and his colleagues have been able to assess the mass balance of alpine mountain glaciers by comparing historical topographic maps and DEMs derived from ASTER. For instance, they built a model and limited the error in the computation of mass balance from field measurements of China’s Sarytor glacier to less than 150mm/year. Similarly, using techniques established by Dr. Todd Albert,who is also a member of GLIMS, a set of images of the Quelccaya Ice Cap spanning four decades was analyzed to create a history of ice surface area. Overall, Albert found that the ice cap has retreated from 58.9 km2 in 1975 to 40.8 km2 in 2010, with a loss of surface area of 31%. This history matches what has been observed in the field by glaciologists Lonnie Thompson and Henry Brecher since the 1970s. Thanks to GLIMS, the rate of glacier melting can be measured and documented more precisely, providing readers with potential evidence of climate change. The GLIMS data provides solid support for future scientific research and planning in the face of climate change. For other stories on the measurement of glaciers, look here. Spread the...

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Glaciers + Algal Blooms = Good?

Posted by on Oct 23, 2014 in All Posts, Featured Posts, Science | 0 comments

Glaciers + Algal Blooms = Good?

Spread the News:ShareThe pros and cons of algal blooms, high concentrations of phytoplankton in the oceans, are a subject of much debate. But several studies in recent months have examined links between changing polar environments, exponential growth of algal blooms, and potential for carbon reduction. One study, appearing in the journal Nature Communications in May 2014, suggests that ocean iron from glacial melt could have positive effects for polar regions in the face of global warming because of the nutrient quality for algae. “The theory goes that the more iron you add, the more productive these plankton are,” John Hawking, a doctoral student at the University of Bristol and lead author of the study, told Scientific American in May. The University of Bristol study examined the amount of a specific type of iron (bioavailable ferrihydrite) released in glacial melt water from the Leverett Glacier in Greenland. The levels of this form of iron found in the glacier allowed Hawking to estimate that an iron flux of up to 400,000 to 2.5 million metric tons could be flowing from Greenland annually. These releases have the potential to be transported up to 900 km from the site of origin and to greatly affect the global iron cycle. New findings coming out of a NASA-sponsored expedition off the coasts of Alaska discovered a massive algal bloom in this polar region as well. Contrary to Hawking’s study, the ICESCAPE expedition conducted by NASA in the Beaufort and Chukchi seas determined the growth in algae was a product of younger and thinning ice. Because of the changes in ice density due to Alaska’s warming climate, more sunlight is able to reach the water underneath the ice packs, according to researchers on the expedition. Therefore, the environment is more favorable for the phytoplankton. Historically, expanding algae populations in other parts of the globe have generated many negative side effects. For example, the decay of algae during a bloom can suck nutrients and oxygen out of the water creating a dead zone. These low-oxygen areas reduce the productivity of wildlife, decrease their productive capacity, and can even kill them. Further, humans experience the effects of algal blooms through the ingestion of toxic substances via shellfish. Yet, in the wake of information about the connection of algae growth and a warming world, studies are taking more effort to explore the positive consequences of algal blooms. A study conducted by the USGS Woods Hole Oceanographic Institution proposes that increases of phytoplankton in polar regions will serve as a new food source for wildlife and will offer increased carbon capture in these areas. The greater numbers of phytoplankton, the greater volume of carbon the population will consume during photosynthesis. Some scientists believe an increasing number of algal blooms will deplete carbon stores in the ocean, resulting in greater absorption of atmospheric carbon by the sea. Additionally, when the phytoplankton die, they often retain much of the stored carbon and carry it down to the ocean floor. Scientists are not certain how the interplay between phytoplankton and ocean carbon will develop because ocean uptake of carbon (especially, in the deep water) can occur on a long timescale, and because it is not yet clear how much carbon is retained versus released during algae death. With all of this in mind, scientists are hopeful that the correlation of glacial melt, encouraging environments, and algal growth will have a net-positive effect. Further study of this natural bioengineering project will definitely aide scientists in understanding climate change trends.   Spread the...

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