Earth Science Studies

NASA/Forest Service Maps Aid Fire Recovery

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The 2013 Rim fire in and near Yosemite National Park, California, was the third largest in the state’s history, burning more than 250,000 acres. Almost two years later, forest restoration efforts are still ongoing. Image credit: USFS/Mike McMillan

 Fast Facts:

  • New maps of burn areas from two California megafires are so detailed, they can show individual trees.
  • The maps are being used in rehabilitating the burn areas and protecting wildlife.

New maps of two recent California megafires that combine unique data sets from the U.S. Forest Service and NASA’s Jet Propulsion Laboratory in Pasadena, California, are answering some of the urgent questions that follow a huge wildfire: In all the acres of blackened landscape, where are the live trees to provide seed and regrow the forest? Which dead trees could endanger workers rebuilding roads and trails? What habitats have been created for fire-dependent wildlife species? 

The maps, so detailed that they show individual trees, cover the areas of two California megafires — the 2013 Rim fire, which burned more than 250,000 acres (1,000 square kilometers) near and in Yosemite National Park, and 2014’s very intense King fire near Lake Tahoe — before, during and after the active burns. As the Forest Service directs ongoing recovery and restoration projects in the two areas, it is using the maps to target its efforts toward important goals such as reducing soil erosion and protecting wildlife.

  

The maps include observations from three instruments: JPL’s Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), which collects images in visible light; JPL’s MODIS/ASTER Airborne Simulator (MASTER), which observes in thermal infrared — in other words, it “sees” heat; and lidar data showing terrain and canopy with such high resolution that individual trees are outlined.

Carlos Ramirez, program manager of the USFS’s Remote Sensing Laboratory, McClellan, California, described three ways the Forest Service is currently using the maps:

— “In some areas of the King fire, you don’t see any green for miles and miles,” said Ramirez. “It’s likely there are not going to be any viable seed sources where the fire was that intense. With the AVIRIS data set, we get an inventory of living vegetation and the condition of it. That gives people in charge of putting together restoration plans an idea of where to focus their attention.”

— Wildfires increase erosion by burning off plants that stabilize soil and diffuse rain. Intense burns often create a water-resistant layer atop the soil so that rain runs off instead of soaking in, cutting deep channels and increasing flood and landslide danger downstream. The maps identify where trees and plants are still alive and erosion control is not needed. 

— Ramirez is working with the University of California, Davis, and nongovernmental organizations to manage the goals of simultaneously clearing hazardous burned timber and preserving habitats for as many species as possible. “Some of these high-severity burn patches are highly desirable habitats,” he said. The maps allow the team to better assess habitat quality for species such as the black-backed woodpecker, which thrives on beetles that live in dead trees.

 

These before-and-after lidar images from the King fire show an area on the west side of the Rubicon River where fire damage was severe. Blue is ground level; lighter colors are higher. A road, bordered by dense trees in the before image, and part of a bridge (green) are at center. Image credit: USFS
 

The NASA observations were acquired in the development of a satellite mission called the Hyperspectral Infrared Imager (HyspIRI), which will study Earth’s ecosystems and provide critical information on natural disasters. HyspIRI is many years from launch and not yet under construction, but AVIRIS and MASTER are airborne prototypes of its two instruments, developed so that scientists can work out scientific and technological issues in advance. Natasha Stavros of JPL recognized the potential value of the Rim fire observations and began collaborating with Ramirez to assemble the maps. When the King fire broke out, the scientists received additional NASA funding to document that fire and its aftermath as well. They hope to create another set of maps if another California megafire breaks out in 2015.

Scientist Janice Coen of the National Center for Atmospheric Research, Boulder, Colorado, is using the MASTER maps of the King fire in independent research with the Coupled Atmosphere – Wildland Fire Environment model, which simulates the interactions of weather and fires. She hopes to gain insight into why the fire grew so quickly. Fires that intense usually are fanned by high winds, but weather stations around the King fire recorded very little wind when it started. “If you’re using the standard tools, you can’t explain the rapid fire growth,” she said. “The evolution of this fire seems to depend very much on winds the fire itself generated as it burned, and those winds in turn depend on the characteristics of the vegetation the fire had for fuel. It’s a good case study, because the new data sets can distinguish between vegetation characteristics that other data sets don’t distinguish.”

A database of detailed maps is online at: http://wildfire.jpl.nasa.gov/data 

It’s the Final Act for Larsen B Ice Shelf, NASA Finds

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Antarctica’s Larsen B Ice Shelf is likely to shatter into hundreds of icebergs like this one before the end of the decade, according to a new NASA study. Image credit: NSIDC/Ted Scambos

A new NASA study finds the last remaining section of Antarctica’s Larsen B Ice Shelf, which partially collapsed in 2002, is quickly weakening and is likely to disintegrate completely before the end of the decade.

A team led by Ala Khazendar of NASA’s Jet Propulsion Laboratory in Pasadena, California, found the remnant of the Larsen B Ice Shelf is flowing faster, becoming increasingly fragmented and developing large cracks. Two of its tributary glaciers also are flowing faster and thinning rapidly.

“These are warning signs that the remnant is disintegrating,” Khazendar said. “Although it’s fascinating scientifically to have a front-row seat to watch the ice shelf becoming unstable and breaking up, it’s bad news for our planet. This ice shelf has existed for at least 10,000 years, and soon it will be gone.”

Ice shelves are the gatekeepers for glaciers flowing from Antarctica toward the ocean. Without them, glacial ice enters the ocean faster and accelerates the pace of global sea level rise. This study, the first to look comprehensively at the health of the Larsen B remnant and the glaciers that flow into it, has been published online in the journal Earth and Planetary Science Letters.

Khazendar’s team used data on ice surface elevations and bedrock depths from instrumented aircraft participating in NASA’s Operation IceBridge, a multiyear airborne survey campaign that provides unprecedented documentation annually of Antarctica’s glaciers, ice shelves and ice sheets. Data on flow speeds came from spaceborne synthetic aperture radars operating since 1997.

http://www.jpl.nasa.gov/video/download.php?id=1376&download=hdmov

Khazendar noted his estimate of the remnant’s remaining life span was based on the likely scenario that a huge, widening rift that has formed near the ice shelf’s grounding line will eventually crack all the way across. The free-floating remnant will shatter into hundreds of icebergs that will drift away, and the glaciers will rev up for their unhindered move to the sea.

Located on the coast of the Antarctic Peninsula, the Larsen B remnant is about 625 square miles (1,600 square kilometers) in area and about 1,640 feet (500 meters) thick at its thickest point. Its three major tributary glaciers are fed by their own tributaries farther inland. 

“What is really surprising about Larsen B is how quickly the changes are taking place,” Khazendar said. “Change has been relentless.”

The remnant’s main tributary glaciers are named Leppard, Flask and Starbuck — the latter two after characters in the novel Moby Dick. The glaciers’ thicknesses and flow speeds changed only slightly in the first couple of years following the 2002 collapse, leading researchers to assume they remained stable. The new study revealed, however, that Leppard and Flask glaciers have thinned by 65-72 feet (20-22 meters) and accelerated considerably in the intervening years. The fastest-moving part of Flask Glacier had accelerated 36 percent by 2012 to a flow speed of 2,300 feet (700 meters) a year — comparable to a car accelerating from 55 to 75 mph.

Flask’s acceleration, while the remnant has been weakening, may be just a preview of what will happen when the remnant breaks up completely. After the 2002 Larsen B collapse, the glaciers behind the collapsed part of the shelf accelerated as much as eightfold — comparable to a car accelerating from 55 to 440 mph.

The third and smallest glacier, Starbuck, has changed little. Starbuck’s channel is narrow compared with those of the other glaciers, and the small glacier is strongly anchored to the bedrock, which, according to authors of the study, explains its comparative stability.

“This study of the Antarctic Peninsula glaciers provides insights about how ice shelves farther south, which hold much more land ice, will react to a warming climate,” said JPL glaciologist Eric Rignot, a coauthor of the paper.

The research team included scientists from JPL; the University of California, Irvine; and the University Centre in Svalbard, Norway. The paper is online at: http://go.nasa.gov/1bbpfsC.

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives and safeguard our future. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

For more information about NASA’s Earth science activities, visit: http://www.nasa.gov/earth.

NASA Administrator Statement on House Authorization Bill That “Guts the Earth Science Programs”

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April 30, 2015
RELEASE 15-080
NASA Administrator Statement on House Authorization Bill 

The following is a statement from NASA Administrator Charles Bolden on the House of Representatives’ NASA authorization bill:

“The NASA authorization bill making its way through the House of Representatives guts our Earth science program and threatens to set back generations worth of progress in better understanding our changing climate, and our ability to prepare for and respond to earthquakes, droughts, and storm events.   

“NASA leads the world in the exploration of and study of planets, and none is more important than the one on which we live.

“In addition, the bill underfunds the critical space technologies that the nation will need to lead in space, including on our journey to Mars.”

NASA, USGS Begin Work on Landsat 9 to Continue Land Imaging Legacy

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NASA and the U.S. Geological Survey (USGS) have started work on Landsat 9, planned to launch in 2023, which will extend the Earth-observing program’s record of land images to half a century.

The Landsat program has provided accurate measurements of Earth’s land cover since 1972. With data from Landsat satellites, ecologists have tracked deforestation in South America, water managers have monitored irrigation of farmland in the American West, and researchers have watched the growth of cities worldwide. With the help of the program’s open archive, firefighters have assessed the severity of wildfires and scientists have mapped the retreat of mountain glaciers.

The President’s fiscal year 2016 budget calls for initiation of a Landsat 9 spacecraft as an upgraded rebuild of Landsat 8, as well as development of a low-cost thermal infrared (TIR) free-flying satellite for launch in 2019 to reduce the risk of a data gap in this important measurement. The TIR free flyer will ensure data continuity by flying in formation with Landsat 8. The budget also calls for the exploration of technology and systems innovations to provide more cost effective and advanced capabilities in future land-imaging missions beyond Landsat 9, such as finding ways to miniaturize instruments to be launched on smaller, less expensive satellites.

“Moving out on Landsat 9 is a high priority for NASA and USGS as part of a sustainable land imaging program that will serve the nation into the future as the current Landsat program has done for decades,” said John Grunsfeld, associate administrator for science at NASA Headquarters, Washington. “Continuing the critical observations made by the Landsat satellites is important now and their value will only grow in the future, given the long term environmental changes we are seeing on planet Earth.”

Because an important part of the land imaging program is to provide consistent long-term observations, this mission will largely replicate its predecessor Landsat 8. The mission will carry two instruments, one that captures views of the planet in visible, near infrared and shortwave-infrared light, and another that measures the thermal infrared radiation, or heat, of Earth’s surfaces. These instruments have sensors with moderate resolution and the ability to detect more variation in intensity than the first seven satellites in the Landsat program.

The Landsat 9 mission is a partnership between NASA and the USGS. NASA will build, launch, perform the initial check-out and commissioning of the satellite; USGS will operate Landsat 9 and process, archive, and freely distribute the mission’s data.

“Landsat is a remarkably successful partnership,” said Sarah Ryker, USGS deputy associate director for climate and land use change, Reston, Virginia. “Last year the White House found that GPS, weather satellites, and Landsat are the three most critical types of Earth-orbiting assets for civil applications, because they’re used by many economic sectors and fields of research. Having Landsat 9 in progress, and a long-term commitment to sustainable land imaging, is great for natural resource science and for data-driven industries such as precision agriculture and insurance.”

NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will lead development of the Landsat 9 flight segment. Goddard will also build the Thermal Infrared Sensor (TIRS), which will be similar to the TIRS that the center built for Landsat 8. The new improved TIRS will have a five-year design lifetime, compared to the three-year design lifetime of the sensor on Landsat 8.

“This is good news for Goddard, and it’s great news for the Landsat community to get the next mission going,” said Del Jenstrom, the Landsat 9 project manager at NASA Goddard. “It will provide data consistent with, or better than, Landsat 8.”

With decades of observations, scientists can tease out subtle changes in ecosystems, the effects of climate change on permafrost, changes in farming technologies, and many other activities that alter the landscape.

“With a launch in 2023, Landsat 9 would propel the program past 50 years of collecting global land cover data,” said Jeffrey Masek, Landsat 9 Project Scientist at Goddard. “That’s the hallmark of Landsat: the longer the satellites view the Earth, the more phenomena you can observe and understand. We see changing areas of irrigated agriculture worldwide, systemic conversion of forest to pasture – activities where either human pressures or natural environmental pressures are causing the shifts in land use over decades.”

“We have recognized for the first time that we’re not just going to do one more, then stop, but that Landsat is actually a long-term monitoring activity, like the weather satellites, that should go on in perpetuity,” Masek said.

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives, and safeguard our future. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

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NASA Joins Forces to Put Satellite Eyes on Threat to U.S. Freshwater

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Toxic algal blooms like this one in Lake Erie in 2011 can cause human and animal health risks, fish kills, and degrade drinking water supplies. Image Credit: USGS/NASA Earth Observatory

NASA has joined forces with the U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration, and U.S. Geological Survey to transform satellite data designed to probe ocean biology into information that will help protect the American public from harmful freshwater algal blooms.

Algal blooms are a worldwide environmental problem causing human and animal health risks, fish kills, and taste and odor in drinking water. In the United States, the cost of freshwater degraded by harmful algal blooms is estimated at $64 million annually. In August 2014, officials in Toledo, Ohio, banned the use of drinking water supplied to more than 400,000 residents after it was contaminated by an algal bloom in Lake Erie.

The new $3.6 million, multi-agency effort will use ocean color satellite data to develop an early warning indicator for toxic and nuisance algal blooms in freshwater systems and an information distribution system to aid expedient public health advisories.

“The vantage point of space not only contributes to a better understanding of our home planet, it helps improve lives around the world,” said NASA Administrator Charles Bolden. “We’re excited to be putting NASA’s expertise in space and scientific exploration to work protecting public health and safety.”

Ocean color satellite data from NASA’s Aqua, the USGS-NASA Landsat, and the European Space Agency’s Sentinel-2 and -3 are currently available to scientists, but are not routinely processed and produced in formats that help state and local environmental and water quality managers. Through this project, satellite data on harmful algal blooms developed by the partner agencies will be converted to a format that stakeholders can use through mobile devices and web portals.

“Observations from space-based instruments are an ideal way to tackle this type of public health hazard because of their global coverage and ability to provide detailed information on material in the water, including algal blooms,” said Paula Bontempi of the Earth Science Division at NASA Headquarters in Washington.

NOAA and NASA pioneered the use of satellite data to monitor and forecast harmful algal blooms. Satellites allow for more frequent observations over broader areas than water sampling. The satellite data support NOAA’s existing forecasting systems in the Gulf of Mexico and Great Lakes.

“Observing harmful algae is critical to understanding, managing, and forecasting these blooms,” said Holly Bamford, acting NOAA assistant secretary for conservation and management and deputy administrator in Washington. “This collaboration will assure that NOAA’s efforts will assist the coastal and inland public health officials and managers across the country to distribute this information to the community in an easily understandable fashion, making them more resilient to environmental events.”

The new network builds on previous NASA ocean satellite sensor technologies created to study the global ocean’s microscopic algal communities, which play a major role in ocean ecology, the movement of carbon dioxide between the atmosphere and ocean, and climate change. These sensors detect the color of the sunlit upper layer of the ocean and are used to create indicators that can help identify harmful algal blooms.

Under certain environmental conditions, algae naturally present in marine and fresh waters rapidly multiply to create a bloom. Some species of algae called cyanobacteria produce toxins that can kill wildlife and domestic animals and cause illness in humans through exposure to contaminated freshwater and the consumption of contaminated drinking water, fish or shellfish. Cyanobacteria blooms are a particular concern because of their dense biomass, toxins, taste and odor.

“EPA researchers are developing important scientific tools to help local communities respond quickly and efficiently to real-time water quality issues and protect drinking water for their residents,” said EPA Administrator Gina McCarthy. “Working with other federal agencies, we are leveraging our scientific expertise, technology and data to create a mobile app to help water quality managers make important decisions to reduce negative impacts related to harmful algal blooms, which have been increasingly affecting our water bodies due to climate change.”

The project also includes a research component to improve understanding of the environmental causes and health impacts of cyanobacteria and phytoplankton blooms across the United States. Blooms in lakes and estuaries are produced when aquatic plants receive excess nutrients under suitable environmental conditions. Various land uses, such as urbanization and agricultural practices, change the amount of nutrients and sediment delivered in watersheds, which can influence cyanobacterial growth.

Researchers will compare the new freshwater algal blooms data with satellite records of land cover changes over time to identify specific land-use activities that may have caused environmental changes linked to the frequency and intensity of blooms. The results will help to develop better forecasts of bloom events.

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives, and safeguard our future. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term satellite data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

For more information on NASA’s Earth science activities, visit: http://www.nasa.gov/earth 

Space Radar Helps Track Underground Water Pollution Risk

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Urban growth in Milan, Italy. In this region, urbanization has increased the potential for groundwater contamination. Image credit: Wikimedia Commons

Fast Facts:

› Groundwater pollution is a worldwide threat to water availability.

› A new technique uses satellite observations of land use changes to assess a region’s risk of groundwater pollution.

The next time you’re digging for buried treasure, stop when you hit water. That underground resource is more valuable than all legendary hoards combined. Ninety percent of Earth’s available fresh water is beneath the surface at any particular time. We drink it, we grow our food with it, and we power industries with it.

We also pollute it. When pollutants get into groundwater, they can stay there for decades. Cleanup efforts are difficult, expensive and not always successful. It would be better to protect groundwater from contamination in the first place, but risks to groundwater are moving targets. Although unchanging factors such as porous soil or shallow aquifer depth play a role, the greatest risk comes from the source of the pollutants: people. And people are always moving. A growing city, in particular, usually means a growing threat to groundwater quality. To lock on to the moving target of groundwater risk, planners worldwide need up-to-date information on how people are changing the land surface.

Son Nghiem, a research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, has devised a new technique to use satellite observations of changes in land use to assess the threat of groundwater pollution by a common group of polluting compounds called nitrates. “To test the method, we successfully conducted the Po Plain Experiment [POPLEX] in northern Italy,” said POPLEX leader Marco Masetti, a professor at the University of Milan, Italy. Combining data from the experiment with satellite data and two other data sets on population and land use, they discovered that in this region, groundwater is more vulnerable in urban than in agricultural areas. The satellite data produced a more accurate map of groundwater risks than either of the other data sets.

Nghiem’s new technique uses data from NASA’s QuikScat scatterometer, a satellite managed by JPL. The method improves the “focus” of the QuikScat image from a pixel size of about 15 miles (25 kilometers) per side to 0.6 mile (1 kilometer) per side, capturing far more detail on how the landscape has changed. Nghiem explained his technique takes advantage of the fact that human-made structures bounce back more of the radar signal than does soil or vegetation. Since large buildings with steel frames are concentrated in cities, the strength of the return signals is a good measure of urbanization.

Lombardy, the region of Italy where the POPLEX experiment took place, “is both one of the most urbanized and one of the most agricultural regions in Italy,” said Stefania Stevenazzi, a doctoral candidate at the University of Milan and lead author of a paperon the research, which appears in the March 19 Hydrogeology Journal. The city of Milan is in the north, and the southern part of the region is mainly farmland. Lombardy’s farmers have usually been blamed for nitrate pollution in the region’s aquifers because nitrates are used as fertilizers, but the compounds also have urban sources, including leaks from sewage systems.

The research team produced three groundwater vulnerability maps based on observed changes from 2000 to 2009. Each map used the same hydrological and geological data, but a different data set representing human factors: census results, a high-resolution aerial photographic survey and the QuikScat observations processed by Nghiem’s method. Statistical techniques were applied to rank the vulnerability of every part of the plain. Water samples from about 200 wells were used to verify the results.

The three maps agreed that in Lombardy, urban sources of nitrate were more important than the rural in polluting groundwater. The QuikScat map, however, proved to match the water samples most accurately. For example, the map using census data indicated that several areas in greater Milan were not at much risk, whereas the satellite data caught the reality that these areas are highly vulnerable. That is because censuses place people at their home addresses, but most of the people in Milan’s labor force are commuters who spend many waking — and polluting — hours at work.

Stevenazzi added, “Our analysis shows how much changes in land use were related to increasing or decreasing contamination in the 2000s. These results are also useful to evaluate how future land-use plans can be developed appropriately to safeguard groundwater quality and human health.”

For more information on the Po Plain Experiment, see:

http://urban.jpl.nasa.gov/poplex/description.html

For more on QuikScat, please visit:

http://winds.jpl.nasa.gov/missions/quikscat

JPL is managed for NASA by the California Institute of Technology in Pasadena.

Let It Go! SMAP Almost Ready to Map Frozen Soil

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SMAP will monitor the frozen or thawed state of the global landscape north of 45 degrees north latitude.
SMAP will monitor the frozen or thawed state of the global landscape north of 45 degrees north latitude. Image credit: UCAR/Carlye Calvin

Those who feel as though they’ve been living in the never-ending winter of the movie “Frozen” this year may be glad to hear that the spring thaw is now typically arriving up to two weeks earlier in the Northern Hemisphere than it did 20 to 30 years ago. But the changing date of the spring thaw has consequences far beyond reducing the number of mornings when you have to scrape off your windshield.

One ecosystem where scientists would most like to understand the effects of changing freeze/thaw cycles is boreal forests, the great ring of green covering the land nearest the North Pole. The forests of Alaska, Canada, Scandinavia and Siberia cover almost 15 percent of Earth’s land surface. The Arctic is warming more quickly than lower latitudes, and the way these forests respond to this rapid change could provide valuable clues about our planet’s warmer future.

But we know very little about how the boreal forests are changing. Millions of square miles have no roads or even villages. “What we have now are very sparse, seasonal measurements from the ground,” said John Kimball, a professor of systems ecology at the University of Montana, Missoula, and a member of the science team for NASA’s Soil Moisture Active Passive (SMAP) mission, launched Jan. 31. “We do have long-term, global satellite data sets that are sensitive to freeze-thaw, but they tend to be very coarse.” That means each measurement averages the status of a large area. Like a mosaic made of large tiles, these data cannot show much detail.

That’s about to change. By the end of April, SMAP will begin monitoring the frozen or thawed state of the landscape north of 45 degrees north latitude (about the latitude of Minneapolis) every two days. The primary mission of SMAP is to measure the amount of moisture in the top few inches of soil globally, but it also detects whether that moisture is frozen or in liquid form. SMAP’s radar measurements, with “tiles” only half a mile to a mile and a half (1 to 3 kilometers) across, will reveal far more detail than scientists now have about the freeze/thaw status of the land surface.

Why is greater detail needed? In the Arctic, the timing of the spring thaw can vary considerably within a small area. Because the returning sun is low on the horizon, the shadowed north side of a hill may remain icy many days after plants have started growing again on the sunlit south side. Those early spring weeks are critical in the short Arctic growing season. “Once the vegetation thaws, boom! Photosynthesis takes off,” Kimball explained. “You can get your highest rates of photosynthesis within a few weeks after the thaw, and a later thaw can mean much lower vegetation growth for the season. We need observations at what I call the landscape level to more precisely monitor those patterns and changes.”

During photosynthesis, plants absorb carbon dioxide from the air. The carbon stays in their wood, roots and leaves, and when they die, most of it remains in the soil. That makes undisturbed forests what scientists call carbon sinks — places that remove carbon from the atmosphere. Longer unfrozen seasons in the Arctic give forests more time to grow and spread, increasing the extent of the carbon sink.

On the other hand, climate warming has increased the occurrence of droughts and wildfires in the Arctic. A burning forest spews enormous amounts of carbon into the atmosphere; in scientific terms, it is a carbon source. Thus, global climate change is causing the northern forests both to absorb and to release more carbon.

With so little Arctic data to crunch, models of Arctic land processes do not agree on which of these trends is prevailing, much less what the future could hold. Lack of consensus does not indicate fundamental disagreements on the physical processes involved, according to JPL scientist Josh Fisher, a member of the SMAP algorithm team. The problem is that, at present, if you put the Arctic’s emitted carbon on one side of a scale and absorbed carbon on the other, the scales would almost balance. “The source/sink balance is usually close to zero, and it’s very easy to get on the wrong side of the zero,” he said. Yet the wrong answer on this fundamental question can cascade into a chain of wrong answers in the course of a model simulation. SMAP’s fine-scale observations have the potential to improve modelers’ understanding of both today’s situation and how it may change in the future.

This spring, SMAP will spin up in time to track the spring thaw in the boreal forest with the detail scientists need — as Princess Anna in “Frozen” says, “For the first time in forever.”

For more about SMAP, visit:

http://smap.jpl.nasa.gov/

JPL is managed for NASA by the California Institute of Technology in Pasadena.

U-Texas & NASA: Study Sees New Threat to East Antarctic Ice

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IMG_3677
This is the East Antarctic coastline. Icebergs are highlighted by the sunlight, and the open ocean appears black. Image credit: NASA

Researchers at the University of Texas at Austin, NASA and other research organizations have discovered two seafloor troughs that could allow warm ocean water to reach the base of Totten Glacier, East Antarctica’s largest and most rapidly thinning glacier. The discovery likely explains the glacier’s extreme thinning and raises concern about its impact on sea level rise.

The result, published in the journal Nature Geoscience today, March 16, has global implications because the ice flowing through Totten Glacier alone is equivalent to the entire volume of the more widely studied West Antarctic Ice Sheet. If Totten Glacier were to collapse completely, global sea levels would rise by at least 11 feet (3.3 meters). As in the West Antarctic Ice Sheet, complete collapse of Totten Glacier may take centuries, although the timing of retreat in both places is the subject of intensive research.

This image shows the previously unknown landscape beneath Totten Glacier. Orange arrows point to seafloor troughs deep enough to allow warm water to enter beneath the floating ice. Image credit: UTA/Jamin Greenbaum
This image shows the previously unknown landscape beneath Totten Glacier. Orange arrows point to seafloor troughs deep enough to allow warm water to enter beneath the floating ice. Image credit: UTA/Jamin Greenbaum

East Antarctica has appeared to be stable compared with the rapidly melting western side of the continent. The new finding shows that “Totten Glacier and the East Antarctic Ice Sheet are a much more interesting and dynamic part of the sea level rise story than we’d previously thought,” said co-author Dustin Schroeder, a scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California. Schroeder helped analyze data from an ice-penetrating radar to demonstrate that ocean water could access the glacier through the newfound troughs.

In some areas of the ocean surrounding Antarctica, warm water can be found below cooler water because it is saltier, and therefore heavier, than the shallower water. Seafloor valleys that connect this deep warm water to the coast can especially compromise glaciers, but this process had previously been seen only under the West Antarctic Ice Sheet. Deep warm water had been observed seaward of Totten Glacier, but there was no evidence that it could compromise coastal ice.

The newly discovered troughs are deep enough to give the deep warm water access to the huge cavity under the glacier. The deeper of the two troughs extends from the ocean to the underside of Totten Glacier in an area not previously known to be floating.

The data for this study were gathered as part of the International Collaboration for Exploration of the

The Totten Glacier Catchment (outlined in blue) is a collection basin for ice and snow that flows into the ocean through Totten Glacier alone. The catchment is estimated to contain enough frozen water to raise global sea level by at least 11 feet (3.3 meters). Image credit: Australian Antarctic Division
The Totten Glacier Catchment (outlined in blue) is a collection basin for ice and snow that flows into the ocean through Totten Glacier alone. The catchment is estimated to contain enough frozen water to raise global sea level by at least 11 feet (3.3 meters). Image credit: Australian Antarctic Division

Cryosphere through Airborne Profiling (ICECAP) project, which, together with the East Antarctic component of NASA’s Operation IceBridge mission, made the first comprehensive survey of the Totten Glacier Ice Shelf and nearby regions between 2008 and 2012. Other coauthors of the study come from research organizations and universities in Australia, France and England.

For more information on the new study, see:

http://www.jsg.utexas.edu/news/2015/03/east-antarctica-melting-could-be-explained-by-oceanic-gateways

To learn more about Operation IceBridge and ICECAP, visit:

http://www.nasa.gov/mission_pages/icebridge/

and

http://www.ig.utexas.edu/research/projects/icecap/

The paper is available at:

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2388.html