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A Bolt from the Brown: Why Pollution May Increase Lightning Strikes
Thursday, November 16, 2017
Scientific American reports on a University of Washington paper using World Wide Lightning Location Network data to show that pollution from ship exhaust in the Indian Ocean and South China Sea enhances the probability of lightning by a factor of two. This pollution problem and consequent increase in lightning was shown to occur every year over the last decade or more. Read More
Salt pond in Antarctica, among the saltiest waters on Earth, is fed from beneath
Wednesday, November 15, 2017
At the base of the Transantarctic Mountains lies a geological oddity. Don Juan Pond is one of the saltiest bodies of water on the planet, filled with a dense, syrupy brine rich in calcium chloride that can remain liquid to minus 50 degrees Celsius, far below the freezing point of water. But the source of water and salt to this unusual pond remains a mystery -- even as hints emerge that water in a similar form could exist on Mars.
A new University of Washington study uses the pond’s bizarre chemistry to pinpoint the water’s source. The recent paper, published Sept. 15 in Earth and Planetary Science Letters, reports that it is fed by a regional deep groundwater system and not, as previously suggested, from moisture seeping down from local valley slopes.
“Don Juan Pond is probably one of the most interesting ponds on Earth,” said lead author Jonathan Toner, a UW research assistant professor in Earth and space sciences. “After 60 years of extensive study, we still don't really know exactly where it’s coming from, what drives the fact that it’s visible on the surface, and how it’s changing.”
The perennial pond measures about 100 by 300 meters, the size of a few football fields, and is about 10 centimeters (4 inches) deep on average. It was first visited in 1961 and named after the expedition’s helicopter pilots, Donald Roe and John Hickey, earning it the name Don Juan Pond. The unique salts in the pond lower the freezing point, which is why this saline pond can exist in a place where the temperature ranges from minus 50 to plus 10 degrees Celsius (-58 to +50 F).
The pond was long believed to be fed by deep groundwater. But then a high-profile 2013 paper suggested that near-surface moisture seeps, similar to recurring slope lineae features recently observed on Mars, were transporting salts downhill to create the salt pond.
Toner is a geochemist specializing in the formation and properties of water in extreme environments on Earth, Mars and beyond. For the new study, Toner created a model to compute how salty water changes during evaporation, freezing, and with different water and salt inputs and outputs. In Antarctica’s appropriately named McMurdo Dry Valleys, water evaporation concentrates salts in the pond, which forces some salts to crystallize. These processes, along with inputs and outputs, cause the pond’s water to change over time.
Toner ran his model for two situations: one where the water was gurgling up from beneath, and another where it was trickling down from near-surface seeps. Results show that the observed chemical makeup could only be produced from underneath.
“You couldn't get Don Juan Pond from these shallow groundwaters,” Toner said. “It's definitely coming from the deep groundwater.”
His calculations also show that upwelling groundwater cycles through the pond every six months, meaning the water must exit the pond via some unseen underground outflow.
The pond’s hydrology is important to geologists because nowhere on Earth is more similar to Mars. The Red Planet is extremely cold and dry, and the McMurdo Dry Valleys are one of the coldest and driest locations on Earth.
“If there is water on Mars, it’s probably going to look a lot like this pond,” Toner said. “Understanding how it formed has large implications for where would you expect to find similar environments on Mars.”
Recent studies hint that liquid water might exist on the surface of Mars, potentially harboring life or even eventually supporting long-term human settlements. The darker lines on steep slopes, which look like moisture streaks observed above Don Juan Pond, could be caused by a similar groundwater system.
Toner will be part of a team exploring Don Juan Pond and surrounding areas this December, sponsored by NASA and the National Science Foundation. Researchers will spend six weeks camping near the pond and taking repeated chemical measurements of its liquid. They will also explore the nearby slopes to measure the chemistry of the moisture seeps, and try to find further evidence for the source of salts to Don Juan Pond.
“If we accept that the deep groundwater theory is true, then what we’re seeing could be part of a bigger process that involves quite an extensive aquifer,” Toner said. “When thinking about the implications for a similar environment on Mars, that’s much more exciting than just a localized surface phenomenon.”
For more information, contact Toner at email@example.com.
NASA grant: NNX15AP19GRead More
Ships Cause their own Stormy Seas
Thursday, November 9, 2017
Physics Today (Search and Discovery) of the November 2017 edition reports on research using WWLLN lightning network data: 'Increased lightning frequency over maritime trade routes links pollution to the development of thunderclouds.' Underlying paper by Thornton (Atmos. Sci), Virts (NASA Huntsville), Holzworth (ESS) and Mitchell (JISAO) recently published in Geophysical Research Letters). Read More
50 simulations of the 'Really Big One' show how a 9.0 Cascadia earthquake could play out
Monday, October 23, 2017
One of the worst nightmares for many Pacific Northwest residents is a huge earthquake along the offshore Cascadia Subduction Zone, which would unleash damaging and likely deadly shaking in coastal Washington, Oregon, British Columbia and northern California.
The last time this happened was in 1700, before seismic instruments were around to record the event. So what will happen when it ruptures next is largely unknown.
A University of Washington research project, to be presented Oct. 24 at the Geological Society of America’s annual meeting in Seattle, simulates 50 different ways that a magnitude-9.0 earthquake on the Cascadia subduction zone could unfold.
“There had been just a handful of detailed simulations of a magnitude-9 Cascadia earthquake, and it was hard to know if they were showing the full range,” said Erin Wirth, who led the project as a UW postdoctoral researcher in Earth and space sciences. “With just a few simulations you didn’t know if you were seeing a best-case, a worst-case or an average scenario. This project has really allowed us to be more confident in saying that we’re seeing the full range of possibilities.”
Off the Oregon and Washington coast, the Juan de Fuca oceanic plate is slowly moving under the North American plate. Geological clues show that it last jolted and unleashed a major earthquake in 1700, and that it does so roughly once every 500 years. It could happen any day.
Wirth’s project ran simulations using different combinations for three key factors: the epicenter of the earthquake; how far inland the earthquake will rupture; and which sections of the fault will generate the strongest shaking.
Results show that the intensity of shaking can be less for Seattle if the epicenter is fairly close to beneath the city. From that starting point, seismic waves will radiate away from Seattle, sending the biggest shakes in the direction of travel of the rupture.
“Surprisingly, Seattle experiences less severe shaking if the epicenter is located just beneath the tip of northwest Washington,” Wirth said. “The reason is because the rupture is propagating away from Seattle, so it’s most affecting sites offshore. But when the epicenter is located pretty far offshore, the rupture travels inland and all of that strong ground shaking piles up on its way to Seattle, to make the shaking in Seattle much stronger.”
The research effort began by establishing which factors most influence the pattern of ground shaking during a Cascadia earthquake. One, of course, is the epicenter, or more specifically the “hypocenter,” which locates the earthquake's starting point in three-dimensional space.
Another factor they found to be important is how far inland the fault slips. A magnitude-9.0 earthquake would likely give way along the whole north-south extent of the subduction zone, but it’s not well known how far east the shake-producing area would extend, approaching the area beneath major cities such as Seattle and Portland.
The third factor is a new idea relating to a subduction zone’s stickiness. Earthquake researchers have become aware of the importance of “sticky points,” or areas between the plates that can catch and generate more shaking. This is still an area of current research, but comparisons of different seismic stations during the 2010 Chile earthquake and the 2011 Tohoku earthquake show that some parts of the fault released more strong shaking than others.
Wirth simulated a magnitude-9.0 earthquake, about the middle of the range of estimates for the magnitude of the 1700 earthquake. Her 50 simulations used variables spanning realistic values for the depth of the slip, and had randomly placed hypocenters and sticky points. The high-resolution simulations were run on supercomputers at the Pacific Northwest National Laboratory and the University of Texas, Austin.
Overall, the results confirm that coastal areas would be hardest hit, and locations in sediment-filled basins like downtown Seattle would shake more than hard, rocky mountaintops. But within that general framework, the picture can vary a lot; depending on the scenario, the intensity of shaking can vary by a factor of 10. But none of the pictures is rosy.
“We are finding large amplification of ground shaking by the Seattle basin,” said collaborator Art Frankel, a U.S. Geological Survey seismologist and affiliate faculty member at the UW. “The average duration of strong shaking in Seattle is about 100 seconds, about four times as long as from the 2001 Nisqually earthquake.”
The research was done as part of the M9 Project, a National Science Foundation-funded effort to figure out what a magnitude-9 earthquake might look like in the Pacific Northwest and how people can prepare. Two publications are being reviewed by the USGS, and engineers are already using the simulation results to assess how tall buildings in Seattle might respond to the predicted pattern of shaking.
As a new employee of the USGS, Wirth will now use geological clues to narrow down the possible earthquake scenarios.
“We’ve identified what parameters we think are important,” Wirth said. “I think there’s a future in using geologic evidence to constrain these parameters, and maybe improve our estimate of seismic hazard in the Pacific Northwest.”
Other co-authors are Nasser Marafi, a UW doctoral student in civil and environmental engineering; John Vidale, a former UW professor now at the University of Southern California; and Bill Stephenson with the USGS.
For more information, contact Wirth at firstname.lastname@example.org.
Videos and images for two of the simulations are available here.Read More
Mountain glaciers shrinking across the West
Friday, October 20, 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?
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 in the North Cascades, 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 USGS Washington Water Science Center, Jon Riedel at the National Park Service’s North Cascades National Park and Andrew Fountain at Portland State University. The work was funded by the National Park Service, the USGS and NASA.
Paul Bodin named interim director of Pacific Northwest Seismic Network
Tuesday, October 10, 2017
Paul Bodin, a research professor in the UW’s Department of Earth and Space Sciences, has been named the interim director of the UW-based Pacific Northwest Seismic Network. PNSN is a collaboration between the University of Washington, the University of Oregon and the U.S. Geological Survey that tracks earthquake and volcano activity throughout the two states, with the support of federal, state and private funding.
Former PNSN director John Vidale stepped down to accept a faculty position at the University of Southern California and direct the Southern California Earthquake Center in Los Angeles. The search for his permanent replacement is expected to take about one year.
In the interim, Bodin will also serve as the Washington’s state seismologist, serving on the Washington state Seismic Safety Committee that makes seismic policy recommendations to the state’s Emergency Management Division and Gov. Jay Inslee, as well as answering questions from reporters and the public about earthquake and volcanoes.Bodin will join other regional earthquake experts for a Reddit “Ask Us Anything” Q&A Thursday, Oct. 19 from noon to 2 p.m. PDT
Bodin is an observational seismologist whose research expertise includes studies of earthquake source physics, seismic wave propagation, and the impacts of strong ground shaking on soils. Bodin spent the first part of his career at the University of Memphis. In Tennessee he studied earthquake processes and hazards associated with earthquakes that occur far from tectonic plate boundaries. Such earthquakes are infrequent and poorly understood, but have very large impacts when they do occur. He also performed field studies in the aftermath of large earthquakes in Mexico, California, India and Taiwan, and was part of a U.S. team monitoring underground nuclear testing in the former Soviet Union.
Bodin joined the UW faculty in 2006 to become manager of the PNSN. During more than a decade since he has overseen upgrades of the network’s technology to enable faster and more accurate detection, analysis and communication of ground shaking from a major earthquake. These network improvements have led to the inclusion of Washington and Oregon into ShakeAlert, a West Coast-wide earthquake early warning system that will provide advance warnings for imminent large earthquakes. Bodin has also published academic papers on triggered earthquakes and tremors; seismic wave propagation and aftershocks; exploring swarm seismicity in Richland and Spokane, Washington; and on the potential for developing earthquake early warning systems in Hawaii and Chile.
Bodin earned his bachelor’s degree at the University of California, San Diego, his master’s at California’s Humboldt State University and his doctorate at the University of Colorado, Boulder.
Pollution from ships is changing maritime weather
Friday, October 6, 2017
UW researchers considered 1.5bn strikes recorded in the Indian Ocean and the South China Sea by the World Wide Lightning Location Network (an international collaboration led by Dr Thornton’s colleague, Robert Holzworth) between 2005 and 2016. This report in the Economist discusses the effect on ships burning high sulphur 'bunker' fuel which will have to abide by the new maritime rule to reduce to 20% of current emission allowances for this pollution. Read More
Ship Exhaust Makes Oceanic Thunderstorms More Intense
Thursday, September 7, 2017
Thunderstorms directly above two of the world’s busiest shipping lanes are significantly more powerful than storms in areas of the ocean where ships don’t travel, according to new University of Washington research. A new study mapping lightning around the globe finds lightning strokes occur nearly twice as often directly above heavily-trafficked shipping lanes in the Indian Ocean and the South China Sea than they do in areas of the ocean adjacent to shipping lanes that have similar climates. Simultaneous press release by UW and AGU: http://www.washington.edu/news/2017/09/07/ship-exhaust-makes-oceanic-thunderstorms-more-intense/ and http://news.agu.org/press-release/ship-exhaust-makes-oceanic-thunderstorms-more-intense/ Read More
NASA Report: Hurricane Harvey Heat Engine Analysis Confirmed by WWLLN
Wednesday, September 6, 2017
Under the central ring of clouds that circles the eye, water that had evaporated from the ocean surface condenses, releases heat, and powers the circling winds of the hurricane. The radar on the GPM satellite is able to estimate how much water is falling as precipitation inside of the hurricane, which serves as a guide to how much energy is being released inside the hurricane's central "heat engine." Confirming this radar analysis are lightning flashes observed by the World Wide Lightning Location Network (WWLLN). Read More
Native American youth launch high-altitude balloons for unique perspective on solar eclipse
Monday, August 21, 2017
While many people across the country donned viewing glasses and prepared to watch Monday’s solar eclipse, a group of 100 teenagers from tribes across the Pacific Northwest launched balloons thousands of feet into the air, gaining a novel perspective of the eclipse -- and the chance to send meaningful artifacts to the edge of space during a memorable moment in history.
The high school students released their balloons from Confederated Tribes of Warm Springs land in north central Oregon, directly in the path of totality that allows viewers to see the moon completely cover the sun. Close to 400 people, mainly tribal members and students, gathered to watch. The event, organized by University of Washington-based Washington NASA Space Grant Consortium and the Northwest Earth and Space Sciences Pipeline, was the largest effort involving Native American tribes during the eclipse.
In addition to launching the giant weather balloons, students from each school attached culturally significant items, called payloads, to theballoons and sent them high into the sky. Their artifacts nearly reached space before returning to the ground.
“This is the first time many of the students get to participate in a cutting-edge experiment of this type,” said the consortium’s director, Robert Winglee, a UW professor of Earth and space sciences. “Seeing their own payloads at the rim of space is quite exciting. This different perspective will hopefully awaken other ideas for gaining different perspectives on their own lives and their own career paths.”
Over the past couple of years, consortium staff visited many of the schools participating in the eclipse balloon launch, introducing students to space research and various NASA projects. The goal is to bring STEM-related topics to the students in culturally relevant ways, said outreach specialist Isabel Carrera Zamanillo.
- Tweets from Seattle Times reporter Hal Bernton covering the launch in Warm Springs
- UW solar eclipse experts
The eclipse project is a tangible way to further involve these students.
“Participation in this eclipse is just a next step for students,” said Carrera Zamanillo, who is also a graduate fellow with the UW’s Center for Environmental Politics. “This is a continuing effort from two years of visiting tribes, and it is a nice event where we can congregate together.”
Each of the 12 student teams created a small payload to attach to the high-altitude balloons. These items are important artifacts to students and included carved wooden instruments, feathers, whistles and a small paddle. Some students also designed electronic sensors that were placed in the balloons and delivered data on temperature, altitude and distance traveled as they soared high into the sky.
The balloons can reach altitudes of 110,000 feet and were fitted with cameras and GPS trackers. The four balloons were released in pairs before the start of the total eclipse, with the hope that the cameras would capture a unique perspective.
As expected, the balloons popped after two and a half hours of flight, and parachutes helped the artifacts and electronic equipment fall safely to the ground. The items landed about 20 miles from the launch site and teams planned to recover them with the help of GPS. About 35 UW-affiliated volunteers, including undergraduate students, graduate students and faculty, joined consortium staff in Oregon to help with the event.
NASA released several similar weather balloons in conjunction with the solar eclipse -- including a launch off the Oregon coast -- that intended to provide different views along the path of the eclipse.
The consortium’s leaders hope this experience will encourage students to build payloads that could hitch a ride on current space-flight missions. Blue Origin, for example, has carrying capacity for such artifacts, Winglee said.
“We can encourage the students and say, ‘Look, you’ve done high-altitude balloons, why don’t you go all the way?’ I think this is a steppingstone for students,” he said.Read More