Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mountain glaciers shrinking across the West

23.10.2017

Until recently, glaciers in the United States have been measured in two ways: placing stakes in the snow, as federal scientists have done each year since 1957 at South Cascade Glacier in Washington state; or tracking glacier area using photographs from airplanes and satellites.

We now have a third, much more powerful tool. While he was a doctoral student in University of Washington's Department of Earth and Space Sciences, David Shean devised new ways to use high-resolution satellite images to track elevation changes for massive ice sheets in Antarctica and Greenland. Over the years he wondered: Why aren't we doing this for mountain glaciers in the United States, like the one visible from his department's office window?


This map shows the elevation change of Mount Rainier glaciers between 1970 and 2016. The earlier observations are from USGS maps, while the recent data use the satellite stereo imaging technique. Glacier surface elevations have dropped more than 40 meters (130 feet) in some places.

Credit: David Shean/University of Washington

He has now made that a reality. In 2012, he first asked for satellite time to turn digital eyes on glaciers in the continental U.S., and he has since collected enough data to analyze mass loss for Mount Rainier and almost all the glaciers in the lower 48 states. He will present results from these efforts Oct. 22 at the Geological Society of America's annual meeting in Seattle.

"I'm interested in the broad picture: What is the state of all of the glaciers, and how has that changed over the last 50 years? How has that changed over the last 10 years? And at this point, how are they changing every year?" said Shean, who is now a research associate with the UW's Applied Physics Laboratory.

The maps provide a twice-yearly tally of roughly 1,200 mountain glaciers in the lower 48 states, down to a resolution of about 1 foot. Most of those glaciers are in Washington state, with others clustered in the Rocky Mountains of Montana, Wyoming and Colorado, and in California's Sierra Nevada.

To create the maps, a satellite camera roughly half the size of the Hubble Space Telescope must take two images of a glacier from slightly different angles. As the satellite passes overhead, moving at about 4.6 miles per second, it takes images a few minutes apart. Each pixel of the image covers 30 to 50 centimeters (about 1 foot) and a single image can be tens of miles across.

Shean's technique uses automated software that matches millions of small features, such as rocks or crevasses, in the two images. It then uses the difference in perspective to create a 3-D model of the surface.

The first such map of a Mount St. Helens glacier was obtained in 2012, and the first for Mount Rainier in 2014. The project has grown steadily since then to include more glaciers every year.

The results confirm stake measurements at South Cascade Glacier, showing significant loss over the past 60 years. Results at Mount Rainier also reflect the broader shrinking trends, with the lower-elevation glaciers being particularly hard hit. Shean estimates cumulative ice loss of about 0.7 cubic kilometers (900 million cubic yards) at Mount Rainier since 1970. Distributed evenly across all of Mount Rainier's glaciers, that's equivalent to removing a layer of ice about 25 feet (7 to 8 meters) thick.

"There are some big changes that have happened, as anyone who's been hiking on Mount Rainier in the last 45 years can attest to," Shean said. "For the first time we're able to very precisely quantify exactly how much snow and ice has been lost."

The glacier loss at Rainier is consistent with trends for glaciers across the U.S. and worldwide. Tracking the status of so many glaciers will allow scientists to further explore patterns in the changes over time, which will help pinpoint the causes -- from changes in temperature and precipitation to slope angle and elevation.

"The next step is to integrate our observations with glacier and climate models and say: Based on what we know now, where are these systems headed?" Shean said.

Those predictions could be used to better manage water supplies and flood risks.

"We want to know what the glaciers are doing and how their mass is changing, but it's important to remember that the meltwater is going somewhere. It ends up in rivers, it ends up in reservoirs, it ends up downstream in the ocean. So there are very real applications for water resource management," Shean said. "If we know how much snow falls on Mount Rainier every winter, and when and how much ice melts every summer, that can inform water resource managers' decisions."

###

Shean will begin a faculty position this winter in the UW's Department of Civil & Environmental Engineering, where he will explore those questions further for the U.S. as well as for other regions, like high-mountain Asia, where over a billion people depend on glacier-fed rivers for irrigation, hydropower and drinking water.

Co-authors are Anthony Arendt at the UW's Applied Physics Laboratory, Erin Whorton at the Washington Water Science Center, Jon Riedel at the National Park Service and Andrew Fountain at Portland State University. The work was funded by the National Park Service, the USGS and NASA.

For more information, contact Shean at 206-221-8727 or dshean@uw.edu.

Media Contact

Hannah Hickey
hickeyh@uw.edu
206-788-7314

 @UW

http://www.washington.edu/news/ 

Hannah Hickey | EurekAlert!

More articles from Earth Sciences:

nachricht Filling the gap: High-latitude volcanic eruptions also have global impact
20.11.2017 | Institute of Atmospheric Physics, Chinese Academy of Sciences

nachricht Antarctic landscape insights keep ice loss forecasts on the radar
20.11.2017 | University of Edinburgh

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>