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Massive Collision Cracked Young Jupiter’s Core

Fri, 09/13/2019 - 11:22

In the chaotic early days of our solar system, catastrophic collisions were common. Jupiter’s fluid surface does not preserve telltale crater scars, nor is it tilted off its axis like some of its neighbors, but a new study published in Nature has uncovered deeper evidence of a massive impact in Jupiter’s past.

Jupiter is a gas giant famous for its sheer size⁠—over 300 times more massive than Earth⁠—and its swirling stormy surface. But until recently, little was known about the planet’s interior. The Juno space probe launched by NASA in 2011 entered Jupiter’s orbit in 2016 and continues to gather data on many aspects of the planet, including Jupiter’s chemical makeup and gravitational and magnetic fields.

“Before the impact, it may have had a very dense core, surrounded by atmosphere. Then a head-on impact spread things out, diluting the core.” The gravitational readings collected so far are “puzzling,” said Andrea Isella, an astronomer at Rice University in Houston and a coauthor on the new study. “We expected Jupiter to have a dense core, but the gravitational readings show that the core is diluted,” he says, meaning that heavier elements common in planetary cores are scattered throughout the hydrogen- and helium-rich envelope that encloses the planet.

Most planets, including Earth, have dense cores made up of heavy elements, like iron, that sink deep into the planet’s interior under the pull of gravity. Even gas giants like Jupiter are thought to initially form as dense, rocky or icy bodies that accumulate thick atmospheres composed of lighter elements, like hydrogen, over time.

Jupiter’s diluted core suggests that a head-on impact with a protoplanet may have stirred up the young planet’s core early in its history, Isella said. “Before the impact, it may have had a very dense core, surrounded by atmosphere. Then a head-on impact spread things out, diluting the core.”.

A major impact could have scattered the core of a young Jupiter about 4.5 billion years ago, producing the diluted core that persists today, as detected by NASA’s Juno spacecraft. Credit: Shang-Fei Liu/Sun Yat-sen University

To investigate the probabilities and potential outcomes of a large impactor colliding with Jupiter, lead author Shang-Fei Liu of Sun Yat-sen University in Guangzhou, China, and colleagues ran thousands of computer simulations of different types of impacts. The simulations showed at least a 40% chance that Jupiter would have collided with another planet within a few million years after its initial formation around 4.5 billion years ago, soon after the dawn of our solar system.

A New Theory

In 1994, the Shoemaker-Levy 9 comet collided with Jupiter, giving scientists a rare opportunity to observe two major objects in the solar system colliding.

“Bigger planets tend to gravitationally attract smaller bodies,” Isella said. “When a small asteroid or comet hits Jupiter, it’s like a fly impacting an 18-wheeler.”

Because of the strong gravitational focusing generated by the massive planet, passing objects are more likely to collide head-on with Jupiter than graze by, Isella said. The simulations showed that collision with a rocky planet about 10 times the size of Earth with a dense core rich in heavy elements could have created enough energy to scatter and dilute Jupiter’s core for billions of years.

A large-impact scenario for Jupiter has not been considered before, said Tristan Guillot, an astrophysicist at Côte d’Azur University in France who was not involved in the new study. “Jupiter does not show outward signs of impact, such as being tilted off its axis, such as we see with Saturn, Uranus, and Neptune.”

“This new study nicely explains the unexpected observations made by the Juno mission.”But it makes sense given what we know about the evolutionary history of our solar system, he said. “The early solar system was a very different beast with many large planetary embryos flying around. The potential for large impacts was likely much higher,” said Guillot, who penned an accompanying News and Views commentary in the same issue of Nature.

“This new study nicely explains the unexpected observations made by the Juno mission,” Guillot said.

More work will be needed to fit the impact theory into existing models of planetary formation, accounting for the distribution and accumulation of elements and heat in young planets, Guillot said. “This is very promising work that may lead us into a new paradigm for how the solar system might have formed: quite chaotically, with lots of giant impacts.”

—Mary Caperton Morton (@theblondecoyote), Science Writer

Finding Faces in Hailstorms

Fri, 09/13/2019 - 11:19

Hail can be among the most damaging of severe weather phenomena, but predicting whether a passing thunderstorm might start spitting pea-sized (or golf ball–sized) hailstones is notoriously difficult. A new approach using machine learning techniques related to facial recognition technology is giving meteorologists a new tool for mapping how various components of a storm might add up to dangerous hail conditions.

Some types of thunderstorms, such as supercells, are more likely to produce hail than others. But the sheer scale of thunderstorms, which can stretch for kilometers and contain multitudes of intrastorm interactions, makes it difficult for computers to accurately model and predict storm behavior, said David John Gagne, a machine learning scientist at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., and lead author of the new study, published in Monthly Weather Review.

“As the computer finds patterns, we teach it to associate those patterns with the probability of whether a given storm will produce hail.”Existing severe weather forecasting models tend to focus on slices of a storm because of the computational complexity of considering the whole storm. “In the past, we have tended to focus on single points or just vertical profiles, but the whole structure of the storm is really important in determining whether or not it will produce hail,” Gagne said.

Drawing upon machine learning technology sometimes used to identify features of individual faces, Gagne and colleagues at NCAR trained a deep learning model called a convolutional neural network to recognize various storm features known to produce hail.

In facial recognition technology, a computer program assesses individual features and the arrangement of features in relation to one another to identify a person’s face.

“To apply this technology to hail forecasting, we fed a computer program lots of data and images of storms and asked it to look at the shape and various components and how they relate to one another,” Gagne said. “As the computer finds patterns, we teach it to associate those patterns with the probability of whether a given storm will produce hail.”

Machine Learning Techniques Expand Meteorological Forecasting

Supercell thunderstorms tend to produce hail because of the large, wide updrafts that carry ice particles from the lower atmosphere into the troposphere, Gagne said. “As these icy embryos travel long distances through the storm, they have time to grow into larger hailstones.”

Making direct observations of how ice particles develop into hailstones is often impossible because of the damage incurred by instruments in hailstorms, said Amy McGovern, a computer scientist at the University of Oklahoma in Norman who was not involved in the new study. “We don’t fully understand the physical process of hail development because we can’t fly planes or send instruments into severe hailstorms without them being destroyed.”

“A deep learning algorithm can pick up on spatial structures inside the storm in three dimensions.”In recent years, machine learning techniques have “exploded in popularity in the field of meteorology” because of a combination of widely available data processing tool kits and cloud storage, McGovern said.

The new study is among the first to use deep learning techniques to look for patterns in hailstorms, said Ryan Lagerquist, a meteorologist at the University of Oklahoma who was also not involved in the new study.

“So far, efforts have focused on traditional machine learning, which has no awareness of the spatial or temporal relationships of the inputs,” Lagerquist said. “A deep learning algorithm can pick up on spatial structures inside the storm in three dimensions, resulting in a more complete picture than you can get with traditional learning models.”

Gagne and colleagues are in the process of transitioning the deep learning model into a real-time weather forecasting model that can be used by the National Weather Service to make predictions about whether a developing storm may produce damaging hail, Gagne said. “It’s still in experimental mode right now, but we’re hoping to have it fully operational in the next year.”

—Mary Caperton Morton (@theblondecoyote), Science Writer

How Volcanic Mountains Cool the Climate

Fri, 09/13/2019 - 11:17

Through subtle shifts and tugs across the planet, activity on Earth perpetually works to balance the global thermostat—from leaves sucking carbon dioxide out of the atmosphere to polar ice reflecting the Sun’s rays back into space. Now, scientists have dug deeper into another source of long-term climate equilibrium: the formation of volcanic mountain ranges.

The team, based at Rice University in Houston, homed in on plutons along the edges of continents. These continental volcanic arcs rise up where oceanic crust sinks and melts beneath continental crust, as in the Andes and North American Cascades.

These mountains initially warm the climate by spewing greenhouse gases from the melted seafloor into the atmosphere as they form. Researchers have long focused on this effect and have generally viewed these continental arcs as net sources of global warmth. But now, new findings suggest these mountain ranges actually counterbalance their warming over geologic time by exposing fresh rock that easily binds with carbon dioxide in rainwater, ultimately shuttling that carbon out of the atmosphere and into the seafloor. The team published their findings in Earth and Planetary Science Letters.

Until now, researchers hadn’t known the extent to which continental arcs might negate their warming through weathering and erosion.“If you have a global flare-up of these arcs, you could help drive greenhouse conditions,” said Cin-Ty Lee, a geologist at Rice University and contributing author on the paper. “But as soon as [the arcs] die, you should be immediately followed by more enhanced cooling.”

The combination of freshly exposed, reactive rock and steep relief expedites the mineral breakdown and erosion that leads to this cooling. The minerals within these particular types of mountains, which tend to be fairly rich in the elements magnesium and calcium, also make them ripe for weathering because those particular elements react easily with carbon dioxide in rainwater to form stable carbonate minerals like limestone.

Aside from weathering, erosion of these high-relief coastal mountains also buries organic material on the seafloor, sealing off even more carbon from the atmosphere.

These concepts aren’t new. But, until now, researchers hadn’t known the extent to which continental arcs might negate their warming through weathering and erosion.

Measuring the Sink Sedimentary rock formed from eroded volcanic arc mountains in Southern California. Credit: Cin-Ty Lee

To sleuth out these dynamics, Lee and his graduate student, Hehe Jiang, studied the chemistry of an ancient arc that was active between 170 million and 85 million years ago along the coast of Southern California, within what is now the Peninsular Ranges. They measured the amount of calcium in both the original plutonic rock and the sediments that eroded from those rocks toward the coast. A loss of calcium in the eroded sediments should signify a breakdown through weathering, so they calculated weathering rates by measuring that calcium loss.

They found that weathering did, indeed, dissolve a large mass of the eroded material—by up to about 50% in some places. From these calculations, they estimated that weathering rates would have negated any warming from volcanic activity over the course of about 40 million to 50 million years.

“I think that was a pretty big finding,” said Clement Bataille, a geochemist at the University of Ottawa who studies weathering processes but wasn’t involved in this study.

Over time, the relief of the mountains dropped, and erosion and weathering rates dropped as well. But those mountains still pull carbon dioxide out of the atmosphere today, thanks, in part, to subsequent tectonic activity that lifted them back up.

Digging Deep in Continental Arcs

In fact, all mountains have the potential to weather and cool the planet in this way. But some do so more vigorously than others depending on their composition, shape, and location.

Volcanic islands, for example, tend to weather more readily than continental arcs because they tend to contain more reactive minerals.

“When we think of volcanic weathering, people always think about island arcs,” said Benjamin Mills, a biogeochemist at the University of Leeds in the United Kingdom who studies past and present climate changes. That’s one reason why continental arcs haven’t received as much attention as potential carbon sinks as island arcs have, he explained.

Mountains across the planet could help the climate bounce back from anthropogenic warming over the course of geologic time.But continental arcs tend to span far wider areas than island arcs, so they can contain more weatherable and erodible material. “It’s something we haven’t thought about as much as we should,” Mills said.

Weathering also requires rainwater or other forms of precipitation. So especially dry land features, like the Tibetan Plateau, aren’t as effective at cooling the climate as wetter mountain ranges like the Andes, Lee explained.

A recent Nature paper suggests Earth today has more reactive, weatherable material than in the recent geologic past. If that’s the case, mountains across the planet could help the climate bounce back from anthropogenic warming over the course of geologic time, said Bataille. “Maybe the Earth will recover much faster than in the past.”

—Laura Poppick (@laurapoppick), Freelance Science Journalist

Ocean Observations for Everyone

Thu, 09/12/2019 - 18:45

A pilot navigating a large container vessel from offshore Atlantic waters into the Delaware Bay and Delaware River has one of the longest pilotages in the United States. Bringing these ships to harbor safely and efficiently requires skill and an enormous amount of data—such as bathymetric and positioning data, real-time tides and currents, and weather predictions. Pilots often make judgment calls around weather and navigational risks. For example, if a hurricane is coming, is it safer for ships to remain offshore, or should pilots navigate into port? These decisions are further complicated for pilots if ships are carrying sensitive cargo or environmentally hazardous materials like oil or natural gas. How can more effective, tailored data help these mariners address risk? The ocean observation community should think of these types of questions and ocean users when developing and deploying new technologies.

It is now time to reframe and expand our thinking to put ocean observations and knowledge to work for all users.Ocean observations collected over the past half century have greatly informed our understanding of how humans are altering Earth. It is now time to reframe and expand our thinking to put ocean observations and knowledge to work for all users, benefiting scientists, large- and small-business owners, resource managers, innovators, and the ocean-loving public.

The upcoming OceanObs’19 conference offers an opportunity to usher in a new phase of making ocean observations useful and accessible to more users. While sharing the latest developments and future prospects, experts from academia, government, and nongovernmental organizations (NGOs) must find ways to engage users routinely and comprehensively at the start of new observing initiatives. It is sometimes tempting—in the interest of saving time and money—for scientists to develop research programs and solutions that look to solve perceived problems for imagined end users outside the laboratory. But without thoroughly engaging people, such as container vessel pilots, to understand their needs, we risk creating solutions for problems that do not exist.

Connecting Researchers with Data Users

Answers to basic research questions inform applied scientific questions that bear on how we can live and thrive in harmony with the ocean, now and in the future. For example, addressing the basic question of how the ocean is taking up more heat from global warming informs understanding of how fast ocean fisheries are moving poleward. And ocean observations are increasingly important to people who rely on the data every day to estimate risk and opportunity, supporting ocean-dependent jobs in coastal and inland communities and safeguarding marine ecosystems. Connecting those people to researchers early in the research planning process is a substantial challenge.

Researchers and technology developers struggle at times with identifying who needs ocean data and exactly what kind of information they need. Researchers’ specialized knowledge often does not overlap with that of fishers, aquaculture farmers, the port and maritime industry, or indigenous people. Like the maritime pilots who mentally integrate multiple data streams while at the helm, many users of ocean data know what they need and what is not helpful but do not have the time or personal connections with researchers to request products tailored to their everyday uses. Interdisciplinary partnerships rarely extend far enough past the laboratory door.

When researchers do include end users of information in the early stages of projects, these projects have a greater likelihood of creating lasting and useful products.When researchers do include end users of information in the early stages of projects, these projects have a greater likelihood of creating lasting and useful products. Although this kind of partnership is not the norm, there have been success stories in which better coordination between researchers and ocean users has already provided real-life benefits. In the Pacific Northwest, for example, academic researchers, federal agencies, and resource managers consulted regional shellfish growers in creating a website and an app, released in 2012, to provide real-time ocean acidification and water quality data to support the shellfish aquaculture industry. Now high-quality updated ocean observations are available in growers’ pockets, in the context and format most useful to them.

In New England and the mid-Atlantic, the development of regional ocean data portals through the ocean planning process provides another example of a heavily data-based process with a forward looking vision resulting in products developed with coastal managers, federal agencies, industry, and scientists to make informed and strategic management decisions. The Northeast Ocean Data portal, for example, currently includes more than 5,000 data layers, along with metadata where appropriate, on a wide range of ecosystem and human activities encompassing marine life, fisheries, maritime commerce, recreation, national security, and energy infrastructure. During development and continuing since, the data portal team has engaged a range of ocean users to characterize and visualize human activity and ecosystems for the purpose of helping scientists, coastal managers, and people from industry make more informed management decisions.

New opportunities to apply these best practices and lessons learned emerge every day. Off the U.S. East Coast, infrastructure to capture renewable energy—particularly wind energy—is increasing rapidly. Collaborating with developers in industry, the ocean observation community could help address questions regarding potential impacts of wind turbines and other infrastructure before, during, and after installation. Meanwhile, given that these large structures are built to last 30 years or longer, the renewable energy sector could also contribute to ocean observations and advance long-term data sets by, for example, instrumenting wind turbines.

Improving Inclusivity in Ocean Observations

OceanObs’19 provides a potential turning point for the scientific community to begin holistically incorporating the needs of a wider array of end users. Opportunities exist for individual researchers, agencies, and the entire community to engage. At OceanObs’19, we want to see conversations and progress toward three specific goals.

First, when researchers develop new ideas, observational tools, or technologies, they should carefully consider the goals of their projects. This includes considering the underlying truth about whom our research currently benefits and whether it should benefit others to achieve economic and social equity as we extend the ocean observation enterprise. However, we also must also grapple with how to analyze and process existing data in new ways for the benefit not just of subsets of communities but also of whole communities. For instance, traditional knowledge from indigenous communities does not mesh neatly with information measured on fixed temporal and spatial scales by the natural science community. Assessing the two knowledge streams together will provide researchers with a more expansive view of the social-ecological system.

One idea for improving the broader usefulness of ocean observations is for funding agencies and grant makers to include outreach and engagement with potential end users of data and products as requirements of funded activities. Credit: Rafeed Hussain

Second, funding agencies and grant makers must include outreach and engagement with potential end users of data and products as requirements of funded activities. This is becoming increasingly common, but it needs to be systemic. Engagement should start during proposal development and would ideally help shape research questions and/or end products. Researchers should thoughtfully outline an engagement plan and ensure it is broad enough to encompass the range of potential and existing users for specific products. In addition, although funders often evaluate a researcher’s publication record during proposal evaluation as evidence of prior research success, rarely do they examine other metrics of success, such as prior successful stakeholder engagement. This also needs to change.

In many grant and funding programs, resources are provided to collect data but not to support their handoff to, nor their synthesis into and visualization on, archival platforms that house data and make them more publicly accessible.A related issue is how to create structures by which data intended to contribute to the public good (i.e., nonproprietary data) can be shared more effectively and by which those collecting and/or analyzing the data have more ownership of their work through their data’s life cycle. In many grant and funding programs, resources are provided to collect data but not to support their handoff to, nor their synthesis into and visualization on, archival platforms that house data and make them more publicly accessible. As a result, some data platforms are under resourced or outdated, and sometimes data do not even make it onto publicly accessible platforms. To address this, funding agencies and grant makers should require that at least half a person’s time for every project award go toward ensuring that data are archived, with adequate metadata, to public data systems. Although some federal agencies already meet this requirement, it should become standard policy.

Third, a governance panel that coordinates work both within the ocean observation community and with external partners would greatly enhance engagement goals and outcomes. The White House Ocean Policy Committee could direct its ocean science and technology subcommittee to serve in this role. Although the Ocean Policy Committee is engaging the ocean community in dialogues about partnerships, identifying challenges and barriers to advancing science and technology that engage a broad suite of ocean user groups would significantly advance our ability to understand and effectively manage the ocean. The subcommittee could also work to address issues like the balance between data privacy and transparency and how we can efficiently incorporate data from new sources and new technologies into the decision-making process.

Just the First Steps

In a time of exciting ocean observation technology development—tempered by modest budgets—we need to develop solutions for problems that ocean users actually face.The first steps outlined above will not resolve all the remaining questions with respect to increasing inclusivity in ocean observations and research planning. Other questions include the following: How do we build partnerships more effectively among academia, industry, philanthropies, government agencies, and nongovernmental organizations? What can we collectively achieve through better coordination? And how do we ensure that data are used and reused as much as possible? If the research community commits first to grappling with the philosophical questions of who benefits from ocean observations and how to broaden the pool of beneficiaries, then we all will be better equipped to address the longer-term questions around a growing ocean-observing enterprise.

In a time of exciting ocean observation technology development—tempered by modest budgets—we need to develop solutions for problems that ocean users actually face. Models exist for including ocean users in decision-making about observations, synthesis, and applications. Boundary organizations and NGOs are eager to create links and facilitate collaboration among users and researchers. As the ocean observation community more routinely considers who benefits from particular advances, whether users have been adequately included in the development process, and how advances can be equitably shared, ocean observations have the potential to usher in a new era of ocean-based prosperity.

Author Information

Sarah Cooley (scooley@oceanconservancy.org) and Amy Trice, Ocean Conservancy, Washington, D.C.

House Passes Measure to Protect Arctic National Wildlife Refuge

Thu, 09/12/2019 - 18:42

A measure to protect the Arctic National Wildlife Refuge (ANWR) moved forward on 12 September with the Democratically controlled House of Representatives voting 225–193 in favor of keeping oil and gas development out of the large coastal plain area of this vast protected region in northeast Alaska. However, the measure faces stiff opposition in the Republican-controlled Senate.

The Arctic Cultural and Coastal Plain Protection Act would repeal the Arctic National Wildlife Refuge oil and gas program currently included in the 2017 Tax Cuts and Jobs Act (Public Law 115–97). The tax act calls for the secretary of the Department of the Interior (DOI) to establish and administer a program for leasing, developing, producing, and transporting oil and gas in and from Alaska’s coastal plain, which is referred to as area 1002. The 1.5-million-acre area 1002 is part of the 19.6-million-acre refuge, the largest national wildlife refuge in the country. Area 1002, which the indigenous Gwich’in refer to as “the sacred place where life begins,” is a habitat for porcupine caribou and many other species.

“We’re striking back this week to the Trump administration and their philosophy of drill everywhere every time with no exception.”Natural Resources Committee chair Rep. Raúl Grijalva (D-Ariz.) and other advocates for protecting ANWR said that the oil and gas program was slipped into the 2017 legislation, and they are determined to repeal it.

“We’re striking back this week to the Trump administration and their philosophy of drill everywhere every time with no exception,” Grijalva said at an 11 September briefing on Capitol Hill in advance of the House vote about ANWR and also prior to two separate votes to ban offshore oil drilling that the House approved on 11 September.

Grijalva said that the House vote to protect the refuge would set down a marker “to reverse the gross injustice that was forced down the throat of the American people by the Republican Congress two years ago and by this administration.”

“Righting the Wrong of the Republican Tax Scam”

Rep. Jared Huffman (D-Calif.), who introduced the bill to protect the refuge, said that House support for the measure “represents a high water mark in our efforts to protect this very special place.” Huffman, who chairs the Natural Resources Subcommittee on Water, Oceans, and Wildlife, said the bill is “about righting the wrong of the Republican tax scam.”

Huffman also denounced what he said is “the corrupted nature” of the Interior Department and the revolving door between the department and the oil and gas industry. In August, for instance, DOI official Joe Balash, who formerly oversaw oil and gas drilling on federal lands and had favored opening ANWR to oil leasing, resigned to take a position working for a foreign oil company that is advancing an oil development project on Alaska’s North Slope.

“This administration is a wholly owned subsidiary of the oil and gas industry.”“Make no mistake: this administration is a wholly owned subsidiary of the oil and gas industry,” Huffman said. “You might say, ‘That’s hyperbole, that’s an exaggeration.’ And I will grant you that there are also some mining and coal interests that have minority stakes in the Department of Interior these days, but it is mostly big oil that wags the dog of this disgraceful Department of Interior.”

“This administration really thinks that it owns everything and that it can just sell off our public lands or our tribal lands to the highest bidder, and we are trying to stop that,” said Rep. Deb Haaland (D-N.M.), chair of the Natural Resources Subcommittee on National Parks, Forests, and Public Lands.

Huffman added that “there is a bigger picture” to bear in mind. “We know that President Trump and his cronies are attacking science at every turn with Sharpies,” he said, referring to Trump allegedly modifying a National Oceanic and Atmospheric Administration weather map with a magic marker to inaccurately extend the reach of Hurricane Dorian’s impact. “We know that they are threatening reprisals against federal scientists who are just trying to do their job. We know that they are embarrassing us on the world stage with their climate denial, obviously.”

A Tough Sell in the Senate

Huffman and others acknowledged that passage of ANWR protections in the Senate will be a difficult fight. Six Democrats, however, did introduce the Arctic Refuge Protection Act on 11 September. That bill would designate the refuge’s coastal plain as wilderness under the National Wilderness Preservation System.

“We should not have to trade our culture for oil and gas.”“Republicans in the Senate and in this administration need to know that they are deeply on the wrong side of the American people and of history on this issue,” Huffman said. He added that many Republican senators voted for the provision in the tax act to establish an oil and gas program in the ANWR. “They are going to be held accountable for that.”

“It’s going to be harder in the Senate” to pass the bill, said Bernadette Demientieff, executive director of the Gwich’in Steering Committee. “But we’re not giving up. We just can’t. We don’t have a choice but to continue to come down here and educate our senators.”

She added, “We should not have to trade our culture for oil and gas.”

—Randy Showstack (@RandyShowstack), Staff Writer

Is Chicago Water Pollution Halting a Silver Carp Invasion?

Thu, 09/12/2019 - 12:38

Pollution from the Chicago Area Waterway System might be stopping an invasion of silver carp in its tracks. Recent research has found that heavily polluted water flowing south from Chicago might be overloading the fish’s ability to process the toxins.

“Invasive silver carp at the leading edge of their invasion front in the Illinois River seem to be exhibiting responses consistent with their exposure to increased environmental contaminants,” lead researcher Jennifer Jeffrey, a biologist at the University of Manitoba in Winnipeg, Canada, told Eos.

“This provides us with some important clues regarding what might be limiting this invasive species from continuing its progression towards the Great Lakes of North America, when little else has seemed to affect its pervasive spread,” she said.

A Stalled Invasion

Silver carp were introduced into the Mississippi River Basin in the 1970s to combat algae growth. They aggressively spread upriver and were classified as an invasive species in 2007. But the invasion stalled about a decade ago in the Illinois River just north of the junction with the Kankakee River, about 65 kilometers downstream from Lake Michigan.

“There’s a stark change in water quality at that point,” coauthor Cory Suski, an ecologist at the University of Illinois at Urbana-Champaign, said in a statement. “That’s right where the invading front stops.”

“This fish never stops for anything.”This kind of abrupt halt is not typical for an invasive species. “Some invasive species thrive in degraded or disturbed habitats because in these situations they are less likely to encounter resistance from native species,” explained Anthony Ricciardi, an aquatic ecologist at McGill University who was not involved with the study. “Native competitors may be better adapted to natural conditions, so when these conditions change, the natives lose their ‘home field advantage.’”

“This fish never stops for anything,” Suski said. The researchers wanted to determine whether something in the fish’s biology could explain the coincidence.

Fish Versus Pollution

In 2016, the team captured fish from three locations along the Illinois River: one site at the leading edge of the invasion front and two downriver sites with well-entrenched populations. They collected blood and liver samples from the fish to see if specimens from different areas showed any physiological or genetic differences.

“We saw huge differences in gene expression patterns between the Kankakee fish and the two downstream populations,” Suski said. “Fish near Kankakee were turning on genes associated with clearing out toxins and turning off genes related to DNA repair and protective measures.

“Basically, their livers are working overtime and detoxifying pathways are extremely active, which seem to be occurring at the cost of their own repair mechanisms,” he said. “We didn’t see that in either of the downstream populations.” These results were published in Comparative Biochemistry and Physiology, Part D: Genomics and Proteomics in July.

When the Answer to a Problem Is Its Own Problem

Jeffrey said that to her knowledge, this is the only situation we know of where human activity has accidentally halted the spread of an invasive species. U.S. Geological Survey hydrologist William Battaglin, who was not involved with the research, agreed that this scenario might be unprecedented.

“Through the process of improving the water quality, which we should absolutely be doing, there’s a possibility that this chemical barrier could go away.”

The researchers cautioned that they haven’t definitively linked the water pollution to the changes in the carp’s biology. It might yet be a coincidence that the water quality and the fish’s biology show changes at the same location.

“Currently, we don’t know how sensitive silver carp are to the contaminants that are coming out of the Chicago area,” Jeffrey said. The team continues to research the possible connection between the toxins and the genetic changes.

“We’re not saying we should pollute more to keep silver carp out of the Great Lakes. That’s not it,” Suski said. But Chicago area water managers should be aware of the potential connection as the region continues to clean up its waters. “Through the process of improving the water quality, which we should absolutely be doing, there’s a possibility that this chemical barrier could go away,” he said.

“Bottom line,” said Ricciardi, is that “invasive species can exploit a major change in environmental conditions, regardless of whether such a change is considered an improvement or a deterioration in overall habitat quality.”

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

Solar Spike Suggests a More Active Sun

Thu, 09/12/2019 - 12:35

At about the same time the Sun was blowing off the largest flare measured in over a decade, the strength of the magnetic field in its atmosphere hit a record high.

But that may not be abnormal. New research suggests that the Sun’s magnetic field may climb to levels of intensity stronger than currently predicted, a discovery that could have implications for the effects of solar weather on Earth’s technology and infrastructure.

On 6 September 2017, solar astronomers identified a massive X9.3 flare exploding outward from a preexisting sunspot. X describes the most intense class of flare, while the associated number relates to its strength. Most flares are classified between 1 and 9.

The entire area where the X9.3 flare took place had been classified as an active region, where the strongest large-scale magnetic fields are concentrated on the Sun. The Sun also released several other powerful solar flares during the same month, many of them stemming from the same area.

“The magnetic field might be stronger than people have been thinking about.”“It was a very interesting active region,” said Gregory Fleishman, a heliophysicist at the New Jersey Institute of Technology in Newark.

Fleishman was part of a research team that captured measurements of the coronal magnetic field, a historically challenging part of the Sun to study. By probing the field in radio wavelengths and comparing their findings to historical observations, the team discovered that the coronal magnetic field may be more powerful than previously expected.

The team’s findings, along with its technique, may allow researchers to improve understanding of what’s happening in the solar atmosphere and how it could affect Earth. Results were published in August in the Astrophysical Journal Letters.

“The magnetic field might be stronger than people have been thinking about,” Fleishman said. “There might be more energy to drive extreme [space] weather.”

More Powerful Than Ever

The Sun’s corona is the outermost layer in the solar atmosphere. Although it is farther away from the solar center than the photosphere, the bubbling layer of plasma from where sunspots arise, it is significantly hotter.

The Sun’s corona is most easily visible during solar eclipses, and the coronal magnetic field is even more elusive. According to Alex Young, associate director for science in NASA’s Heliophysics Science Division at Goddard Space Flight Center in Greenbelt, Md., the infrared lines needed to measure the magnetic field are impeded by Earth’s temperature and atmosphere and are difficult to study even from space. Most infrared observations are taken by aircraft soaring above the terrestrial atmosphere during an eclipse.

“It’s very difficult to measure magnetic fields in the corona,” Young said.

Current models of the coronal magnetic field are based on observations of the photosphere. Young compares the limits of the model to a shag carpet. The photosphere is like the base, where the weave ties into the carpet. That’s the bulk of what scientists can probe. They can only make a guess about what’s happening at the corona, which Young compares to the surface of the carpet. Complicated physics make it difficult to model coronal processes.

“If you don’t know the details about the kind of threads in the carpet, the kind of material, you can never exactly figure out what the shape of that shag carpet’s going to look like,” Young said.

To overcome this problem, Fleishman and his colleagues turned to radio waves. As a local magnetic field increases in strength, it becomes brighter at higher radio frequencies. Using the radio telescope Nobeyama Radioheliograph, the researchers studied the Sun before and after the 6 September flare, a period of high solar activity, and were able to recover the magnetic field strength at the base of the corona. The Japanese instrument captured solar observations at higher frequencies than previously used, allowing for a more in-depth probing of coronal temperatures.

They found that the coronal magnetic field reached 4,000 gauss, twice as strong as previously reported. Because the field appeared at the highest measurable frequency, it’s possible that the field’s magnetic flux density could be even stronger.

In reviewing historical observations, the researchers found previous instances of high radio measurements that were made before the connection between radio waves and strong magnetic field strength was established. The finding suggests that such extreme fields may not be as rare as previously thought.

That could be bad news for Earth.

Occasionally, the Sun blows clouds of plasma known as coronal mass ejections (CMEs) from its surface. As the material moves through space, it can both harm astronauts and damage satellites. When CMEs or flares collide with Earth’s magnetic field, they can dump charged particles that spiral around the planet, not only creating beautiful auroral displays but also overcharging electrical grids.

Understanding and predicting space weather events have become higher priorities in recent years, and the new study offers hope of improving both.

“We can’t even begin to start thinking about predicting [space weather] until we can measure [coronal magnetic fields],” Young said.

—Nola Taylor Redd, Freelance Science Journalist

Altered Forecasts, Unmonitored Volcanoes, and Other Good Reads

Thu, 09/12/2019 - 12:34

Altered Forecasts and Threatened Firings at the National Weather Service.

President @realDonaldTrump gives an update on Hurricane #Dorian: pic.twitter.com/CmxAXHY5AO

— The White House (@WhiteHouse) September 4, 2019

Of all the bizarre news cycles we’ve been through recently, the president doctoring a hurricane forecast map—and the false claims, pressured scientists, and threats that followed—is one of the strangest, and certainly one of the most dangerous to our trust in experts during times of crises. Three former NOAA chief administrators—D. James Baker, Kathryn Sullivan, and Jane Lubchenco—aren’t standing idly by while scientific integrity gets hammered. —Heather Goss, Editor in Chief

 

Geologists Uncover History of Lost Continent Buried Beneath Europe. Although Atlantis is a myth, Earth apparently does have a history of swallowing up landmasses; scientists have painstakingly compiled evidence of a lost continent, Greater Adria, beneath Europe. —Tshawna Byerly, Copy Editor

 

We’re Barely Listening to the U.S.’s Most Dangerous Volcanoes.

Mount Hood in Oregon is an active volcano that is inadequately monitored, but placing instruments on its flanks would violate the Wilderness Act. Credit: Jeffhollett, CC BY SA 4.0

The lack of adequate monitoring on many of the most potentially hazardous volcanoes in the United States is staggering, especially compared with how countries like Chile and Japan, which face similar dangers, “smother their high-threat volcanoes in scientific instruments.” This is an important and thought-provoking piece about efforts to address this inadequacy—and the somewhat surprising resistance that could still stymie these efforts. —Timothy Oleson, Science Editor

Seven of the 10 most dangerous volcanoes in the United States are part of the Cascade Range, and six of those are not adequately monitored. The article gives you lingering, troubling thoughts about the demographics defining public safety and conservation policies and on what we have and have not learned from the 1980 eruption of Mount St. Helens. —Caryl-Sue, Managing Editor

 

Last Day of the Dinosaurs’ Reign Captured in Stunning Detail. A gripping account of the day the dinosaurs died. I’m a big fan of Maya Wei-Haas’s writing here, especially her description of the “nightmarish sequence of events” that followed the big asteroid strike. —Jenessa Duncombe, Staff Writer

 

Achievement Unlocked.

The most ambitious crossover announcement in space?@NASAInSight just named “@RollingStones Rock” on Mars in honor of the band. Watch @RobertDowneyJr announce the @NASA news live on stage at the Rose Bowl ahead of tonight’s concert. https://t.co/868Gbervw1 #MarsRocks pic.twitter.com/xETMzS0H9y

— NASA JPL (@NASAJPL) August 23, 2019

This ambitious stone rolled superfar on Mars, so NASA’s InSight lander named it Rolling Stones Rock…and got an entire stadium of Rolling Stones fans and RDJ to cheer for it. —Kimberly Cartier, Staff Writer

 

Ages for the Navajo Sandstone.

The Navajo Sandstone extends throughout the southwestern United States, including into Moab, Utah, above. Credit: Stephen T. Hasiotis

The petrified sand dunes in Utah are older than we knew! —Liz Castenson, Editorial and Production Coordinator

 

A Mountain Top Called “Little Man” Falls in Norway, and Residents Weep.

Read this emotional tale of a community waiting for a landslide that geologists predicted would sweep away their town. —Heather Goss, Editor in Chief

 

Nuclear Bomb or Earthquake? Explosions Reveal the Differences.

Yucca Flat, part of the Nevada National Security Site, is pockmarked with subsidence craters left by underground nuclear tests. Credit: U.S. Department of Energy

This quirky experiment sounds like a blast. —Jenessa Duncombe, Staff Writer

 

Perijove 11: Passing Jupiter.



Swoop down and skim above Jupiter’s clouds with this 2018 flyby video from the Juno mission. The swirling storms are so beautiful! —Kimberly Cartier, Staff Writer

AGU and Eos are “Covering Climate Now”

Wed, 09/11/2019 - 17:31

“Human activities are changing Earth’s climate.”

AGU has continually strived to lead the conversation when it comes to climate change—these words lead our official position statement, first adopted in 1998 and evolving over time to reflect the steadily increasing evidence about how human activities are changing our world. (AGU will open a revised statement for member comment later this week.)

One of our most important duties at AGU is to highlight crucial research and translate it for the rest of the world, through the reported news, science updates, and research spotlights you read every day on Eos and through AGU’s newsroom, which highlights the research of our member scientists. That’s why we’ve joined more than 220 news outlets and organizations for the Covering Climate Now initiative, founded by the Columbia Journalism Review and The Nation, in partnership with The Guardian. The initiative “aims to convene and inform a conversation among journalists about how all news outlets—big and small, digital and print, TV and radio, US-based and abroad—can do justice to the defining story of our time.”

Eos has committed to running a full week of climate coverage from 16 to 23 September (in addition to our usual robust coverage) in the run-up to the Climate Action Summit hosted by the United Nations in New York. AGU will also provide tools to reporters covering the climate change story and highlight climate change–related content from our journals, blogs, and elsewhere throughout the week.

Follow along with @theAGU and @AGU_Eos next week using the #CoveringClimateNow hashtag and through our Eos Buzz and AGUniverse newsletters. We’ll also be updating this post with our coverage. AGU and Eos are committed—now and in the future—to getting climate science research in front of the eyes of the public so we can all make the best decisions possible to protect this one world we have.

—Heather Goss (@heathermg), Editor in Chief, Eos; and Nanci Bompey (@nbompey), Public Information, AGU

Water Found in Small, Habitable Zone Planet’s Atmosphere

Wed, 09/11/2019 - 17:30

Astronomers have detected water vapor in the atmosphere of a planet that orbits within the habitable zone of its star.

“This is the only planet we know of outside the solar system that [has] the correct temperature to support water, has an atmosphere, and has water in it, making this planet the best candidate for habitability we know of right now,” Angelos Tsiaras told reporters. Tsiaras is an astronomer at University College London (UCL) in the United Kingdom and the lead author of a new paper on the planet.

This is also the first time that water vapor has been detected in the atmosphere of an exoplanet that is not a gas giant. The discovery was published in Nature Astronomy on 11 September.

Habitable, but Maybe Not Hospitable

K2-18b was discovered by way of the Kepler Space Telescope in 2015. A few months later, Björn Benneke, an astrophysicist at the Université de Montréal in Canada who was not involved with this study, used the Hubble Space Telescope to observe the planet passing multiple times in front of its star at infrared wavelengths. This technique measures the chemical fingerprint of a planet’s atmosphere as starlight passes through it. Tsiaras and his team analyzed those data with their own software when Benneke’s data became publicly available.

The team found that water vapor left a strong signature in the planet’s atmospheric spectrum. Of the hypothetical atmospheres that the team tested, “they all fit the data, but they all point to a significant concentration of water,” as well as of hydrogen and helium, explained coauthor Jonathan Tennyson, also at UCL.

“It’s not at all clear whether the planet is actually a hospitable environment for life to evolve [in].”Benneke’s team confirmed the detection of water vapor in a paper under review by the Astronomical Journal and also show that water vapor might condense and rain down through K2-18b’s atmosphere.

“It’s super exciting to have a first glimpse into the atmosphere of a planet this small,” exoplanet researcher Laura Kreidberg told Eos. Kreidberg, of the Harvard–Smithsonian Center for Astrophysics in Cambridge, Mass., said that K2-18b might be “more like a mini-Neptune than a super-Earth because it still has some hydrogen in its atmosphere.”

“This planet is not a second Earth,” Tsiaras added, because it’s twice the size and 8 times the mass of Earth. It also orbits a cool red star less than half the size of the Sun.

“Even though it’s in the habitable zone,” Kreidberg said, “it’s very different from the Earth, and it’s not at all clear whether the planet is actually a hospitable environment for life to evolve [in].” Kreidberg was not involved with this study.

“The Limit of What We Can Do”

“Fundamentally, Hubble wasn’t designed to do observations of exoplanet atmospheres.”The atmospheric models suggest that water vapor could make up anywhere from 0.01% to 50% of the atmosphere’s composition. The data are not precise enough to narrow down this range or to detect other molecules the atmosphere might have, the researchers found. “With the current data, we can only detect the existence of an atmosphere and the existence of water,” Tsiaras said.

Thomas Beatty, an exoplanet atmosphere researcher at the University of Arizona in Tucson who was not involved with this research, said that for this system, “this appears to be the limit of what we can do with current facilities. Hubble is an amazing observatory, but…fundamentally, Hubble wasn’t designed to do observations of exoplanet atmospheres.”

Upcoming space-based telescopes “were designed from the ground up” to more precise and accurate atmospheric measurements than is currently possible, Beatty said.

And as for telescopes on the ground, Earth’s humid skies complicate the search for water elsewhere. “Ironically,” Tennyson said, “the less like Earth this is, the easier it’s going to be to do from the ground.”

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

New Volcanic Complex Found Below the Southern Tyrrhenian Sea

Wed, 09/11/2019 - 12:25

Subduction and retreat of the Adriatic–Ionian microplate—a sliver of oceanic crust that separated from Africa during the Cretaceous—beneath Eurasia have controlled much of the tectonic and stratigraphic evolution of the western Mediterranean Sea. The subduction forged Mount Vesuvius and other southern Italian volcanoes and their concomitant geohazards, and episodes of rapid rollback of the subducting slab have led to the opening of basins including the Tyrrhenian Sea between Sardinia, Sicily, and mainland Italy.

Tearing and faulting of downgoing oceanic plates are common in subduction systems, sometimes producing faults called Subduction-Transform Edge Propagator (STEP) faults at slab edges that propagate perpendicularly to the subduction strike. This process can allow magma upwellings caused by subduction-induced mantle flow to rise to the surface and has been suggested to explain the presence of volcanic seamounts beneath the southern Tyrrhenian Sea. To date, however, this magmatism has been poorly documented.

Now De Ritis et al. report a detailed investigation of a large volcanic-intrusive complex located about 15 kilometers off the Tyrrhenian coast of Calabria in southwestern Italy. Using a suite of geophysical data, including multibeam sonar bathymetry, as well as seismic reflection, magnetometric, and seismological data, the authors characterized the complex, which formed within the past 780,000 years and had not yet been identified or studied in detail.

The team’s data indicated the presence of numerous magmatic intrusions that reached the seafloor in several locations to form seamounts and other volcanic features like chimneys and lava flows. The researchers divided the complex into two distinct realms: an eastern domain (the Ovidio seamounts), characterized by a series of flat-topped volcanic edifices, and a western domain (the Diamante and Enotrio seamounts), where strike-slip faults deform the volcanic edifices.

Collectively, the results affirm that the newly identified volcanic-intrusive complex originates from decompression melting of mantle material at the northern edge of the Ionian slab. The authors hypothesize that a strike-slip belt associated with the formation of a STEP fault controlled the magma’s ascent and the location of this complex. These findings shed light on magmatic processes occurring along the edges of subducting slabs as well as on the potential geohazard risk in a densely populated region whose volcanic activity was previously believed to be one of the best characterized in the world. (Tectonics, https://doi.org/10.1029/2019TC005533, 2019)

—Terri Cook, Freelance Writer

Will Cigarette Butts Be Our Environmental Legacy?

Wed, 09/11/2019 - 12:24

A smoker takes one last drag of a cigarette, then flicks the butt to the ground and sends it backward with the scrape of a boot.

“People just flick them as if it’s not any sort of waste.”“People just flick them as if it’s not any sort of waste,” said Bas Boots, an ecologist at Anglia Ruskin University in the United Kingdom.

Turns out, they create one of the biggest piles of waste humanity makes: Each year, we smoke about 5.6 trillion cigarettes, and between 4 and 5 trillion of that number wind up in the environment as litter.

“That’s a lot,” Boots said.

Cigarette butts contain cellulose acetate, a microplastic. Each butt can contain up to 12,000 cellulose acetate fibers. These fibers, Boots explained, help catch pollutants from cigarette smoke before they can reach a smoker’s lungs. But the butt stops there, it seems, because research is revealing that littered butts, and the microplastics within them, can have harmful environmental effects. According to research published in Ecotoxicology and Environmental Safety, butts in soils can stunt plant growth.

Fibers of cellulose acetate, a microplastic, filter nicotine and nicotine residue (tar) from cigarette smoke, as seen in these unsmoked (left) and smoked (right) cigarettes. Credit: Akroti, courtesy Wikimedia, CC BY-SA 2.5

Boots, part of the team that conducted the new research, explained that it did not matter if the butt was from a smoked, unsmoked, or partially smoked cigarette—shoots of plants like white clover were still about 28% shorter than normal when exposed to the refuse. This result signaled to the team that the cellulose acetate in butts, rather than burnt or unburnt tobacco, is likely causing the stunting.

Cigarette butts are one of the most commonly found plastic waste items on the planet. During the Ocean Conservancy’s International Coastal Cleanup Day in 2018, butts were the top piece of trash found by volunteer beach cleaners. And microplastics like the ones found in butts are finding their way into every inch of the environment: In 2014, researchers discovered that microplastics can become frozen in Arctic sea ice. As the planet warms, that ice stands to release its load into the oceans, where plastics are already accumulating on the ocean floors and finding their way into animals’ guts.

“We’re now producing so much plastic, and so much of it is leaking into the environment, that it’s almost become sort of like a component of geology, like you would think of a sand grain, or piece of wood,” said Sarah Gabbott, a paleontologist at the University of Leicester in the United Kingdom.

Our Butting Legacy?

But will butts, their plastics, and their concomitant problems stick around as long as sand grains?

“How long do we have to worry about this stuff, assuming we all stop smoking tomorrow?”“That’s one of the questions. How long do we have to worry about this stuff, assuming we all stop smoking tomorrow?” asked ecologist Jan Zalasiewicz, who is also at the University of Leicester and chairs a group that seeks to determine whether human activities warrant the addition of a whole new period to the geologic timescale known as the Anthropocene.

Although we cannot travel into the future to find out if cigarettes and their microplastics will stand the test of time, researchers can look to the recent geologic past for insights. For instance, in the sedimentary records of ancient lakes, archaeologists regularly find the remains of things like wood associated with human settlement, which can remain intact for thousands of years. So when imagining whether or not butts will stick around for at least that long, “rather than ‘will we find them or not?’ I think the answer is almost certainly yes,” Zalasiewicz said.

Just how many butts will persist through time, though, depends on the environment in which the littered butts find themselves, explained Gabbott. It helps, she said, to think about butt preservation the same way a paleontologist might think about the fossil preservation potential of recently dead organisms. Butts, she explained, need to escape at least two atmospheric forces to avoid decay: sunlight and water. UV light works to decomposes butts, and water creates an environment in which butt-eating bacteria can thrive.

Following these principles, Gabbott and her students are working to find out what proportion of the butts littered every year might be preserved. But, for now, she said, there are still more mysteries than answers. “I think we’ll find that UV light is the most important thing—to bury it in the dark,” she said. “But, you know, no one really knows.”

—Lucas Joel, Freelance Journalist

The Scientist Who Connected It All

Wed, 09/11/2019 - 12:24

The centennial of Alexander von Humboldt’s birth was celebrated across the world in 1869. Around that time, the famed globe-trotting explorer and natural systems scientist was memorialized in numerous statues, and many institutions, geographic features, and communities—and almost a U.S. state—would come to bear his name.

Wherever he traveled, Humboldt went to great lengths and personal and monetary expense to conduct detailed geophysical and ecological measurements.But through much of the ensuing century and a half, Humboldt’s global celebrity and status as a scientific luminary diminished, the latter as scientists increasingly eschewed the naturalistic approach of Humboldt and others. Today, many in the United States and elsewhere have only recently rediscovered his ideas and the prominent role he played in establishing the modern natural sciences.

Wherever he traveled, Humboldt went to great lengths and personal and monetary expense to conduct detailed geophysical and ecological measurements. He also excelled at synthesizing the wide range of observations he collected. Although his brother Wilhelm is credited with establishing the modern university model combining research and education, Alexander is reasonably attributed as a founding father of systems science, which characterizes species and processes, for example, in terms of their interconnections rather than in isolation from each other.

This year, 14 September marks Humboldt’s 250th birthday, offering an opportunity to revisit and celebrate his life and contributions to science. AGU is commemorating Humboldt with a new theme in Geochemistry, Geophysics, Geosystems, as well as a Union session at the Centennial Fall Meeting in San Francisco this December.

Life of an Explorer This painting depicts Humboldt studying Alstroemeria flowers on his groundbreaking voyage to South America (here the banks of the Orinoco River in Venezuela.) Credit: Friedrich Georg Weitsch/Alte Nationalgalerie, Public Domain

Alexander von Humboldt was born in Berlin to an established Prussian family in 1769, 2 years his brother Wilhelm’s junior. Their father died when Alexander was 10, and their mother remained only a distant presence, with tutors likely instilling the adventurous spirit that Alexander displayed early on. He pursued an eclectic mix of studies, including languages, anatomy, geology, and astronomy at universities in Hamburg, Jena, and Freiberg. After settling on a mining degree and graduating from the School of Mines in Freiberg in 1792, Humboldt was appointed an inspector of mines near Bayreuth in Bavaria.

In addition to establishing a vocational training program and support network for miners, this appointment led to his first scientific study, in 1793, on vegetation in mines. This work brought him to the attention of the prominent poet Johann Wolfgang von Goethe, who was also a natural historian, and led to a life of science and intellectual exchange. Set free of his day job when he inherited his mother’s fortune in 1796, Humboldt set off to explore the world at the turn of the 18th century. Much of his subsequent life happened on the road and in the salons of Paris and involved discussions with many of the leading intellectuals of the time, from Friedrich Schiller and Louis Agassiz to Henry David Thoreau and Charles Darwin.

Humboldt made a number of important contributions across natural disciplines, establishing the field of biogeography and helping establish ecology and conducting meticulous measurements that informed sweeping theories, such as on links between topography and vegetation. In his life, he undertook two major expeditions, observations from which drove most of his discoveries.

The first—and more significant of the two—brought him to the Americas from 1799 to 1804 on a trip that would eventually change prevailing views of Latin America and its connections to the rest of the world. From its inception, this journey was different from other exploration efforts at the time: It was solely geared toward science.

Humboldt and his colleague Aimé Bonpland annotated this cross-sectional illustration of Chimborazo and Cotopaxi volcanoes (in present-day Ecuador) with detailed information about plant geography based on observations from their travels in South America. The figure accompanied the pair’s “Essay on the Geography of Plants,” originally published in French in 1807. Credit: Public Domain

Humboldt had his sights on data, looking to measure altitudes, temperatures, and the magnetic field; to draw geological cross sections; and to collect rocks, plants, and animals, all while trying to understand the culture of local societies. Most geographers at the time were more interested in defining political boundaries, giving little consideration to Earth’s relief and morphology and often injecting heavy doses of subjective interpretation. Humboldt instead focused on nature and data, and his approach was original: By properly reporting reliefs on maps, he could describe the changing landscape and biogeosphere.

Among other contributions, Humboldt placed Andean flora and fauna into distinct climatic and topographic contexts and described human impacts on climate change as potentially affecting the evolution of society. Humboldt also established links with various notable figures from west of the Atlantic, including future revolutionary leader Simón Bolívar and, on a visit to the United States, President Thomas Jefferson, a fellow scientist who is said to have called Humboldt “the most scientific man of his age.”

After his return to Europe, Humboldt spent much of the rest of his life placing the findings from his Latin American voyage into a global environmental context.After his return to Europe, Humboldt spent much of the rest of his life placing the findings from his Latin American voyage into a global environmental context. His three volumes entitled Relation historique du voyage aux régions équinoxiales du nouveau continent (1814–1825) represent the first report of that expedition. He then expounded on this work in the five-volume Kosmos, which was based on a series of highly successful public lectures in 1827–1828.

Humboldt’s second major expedition was to Russia in 1829, where he reached as far as the Altai Mountains. It represented a compromise after many failed attempts to venture farther to India and elsewhere in Asia. The immediate scientific insights from this expedition were comparatively limited, although he could claim the discovery of diamonds in the Urals and a number of geographic corrections.

A Revolutionary Thinker

By nature, Humboldt was collaborative and open to sharing data. And he continually revised and updated his own published works over his lifetime, emblematic of his interconnected and dynamic view of knowledge and its dissemination.

Reading Alexander von Humboldt, we notice that his approach to science was revolutionary in many ways. First, Humboldt displayed an impressively high level of precision and accuracy in his data collection, paying particular attention to make sure measurements and sample locations were properly georeferenced. He was thus able to create the first global geomagnetic and temperature maps, paving the way to the establishment of general relationships.

Humboldt sits in the library of his Berlin apartment in this mid-19th century painting by Eduard Hildebrandt. Credit: Kunstbibliothek Berlin, Public Domain

Another fundamental aspect of his approach was his search to understand connections between natural processes and their feedbacks. For example, Humboldt analyzed spatiotemporal distributions of and possible connections between earthquakes and volcanic eruptions in great detail, in search of a general theory that could explain their individual causes as well as possible triggering processes. Quantitatively establishing such links in terms of stress triggering of volcanic conduit systems remains an unsolved question in geodynamics and volcanology.

Humboldt appears to have much preferred Paris over Berlin for most of his life, although he ended up being employed by the Prussian court. He died in Berlin in 1859 nearly penniless but as one of the most famous scholars in the world. A German foundation in Humboldt’s name and spirit was established soon after and to this day supports academics worldwide. Grants are given in the humanities and natural sciences for research in Germany and related collaborations abroad. (Both of the authors were lucky to have been Humboldt Foundation scholarship beneficiaries.)

Contrary to the standard in modern scientific literature, Humboldt mixed travel narrative and descriptions of his emotional responses to natural experiences with discussions of his measurements and the theories he derived from them.Humboldt appears to have been an overbearing talker and somewhat self-obsessed, yet he was also unselfish in his support of early-career scientists. He shared his data and samples freely and tried to establish an international and open network of scientists driven by a respect for human rights and equality. Contrary to the standard in modern scientific literature, Humboldt mixed travel narrative and descriptions of his emotional responses to natural experiences with discussions of his measurements and the theories he derived from them. Humboldt wrote that “Nature herself is sublimely eloquent. The stars as they sparkle in firmament fill us with delight and ecstasy, and yet they all move in orbit marked out with mathematical precision.”

High-quality data and the search for a physical unifying theory represent the foundation of Alexander von Humboldt’s innovative and creative scientific approach. The special theme in Geochemistry, Geophysics, Geosystems and the upcoming Union session at the Fall Meeting will celebrate Humboldt’s scientific discoveries. More importantly, we hope to build on his vision for understanding the Earth system as a whole in an open, diverse, and collaborative environment.

For those interested in learning more about Alexander von Humboldt, we recommend the brilliant reevaluation of his life offered in Andrea Wulf’s biography, The Invention of Nature: Alexander von Humboldt’s New World (Vintage, 2015). This has more recently been joined by a beautifully illustrated graphic novel, The Adventures of Alexander von Humboldt (Pantheon Graphic Library, 2019) by Wulf and Lillian Melcher.

Author Information

Thorsten W. Becker (twb@ig.utexas.edu) and Claudio Faccenna, Jackson School of Geosciences, University of Texas at Austin

Molecular Ions Unexpectedly Frequent in Earth’s Magnetosphere

Wed, 09/11/2019 - 11:30

The medium-energy particle ion mass analyzer (MEPi) onboard the Japanese Arase satellite is a high-sensitivity time-of-flight (TOF) ion mass spectrometer capable of detecting both major and minor species of energetic ions in the ~10 to 100 kilo-electron-volt (keV) energy range in the Earth’s inner magnetosphere.

The observed ion TOF spectra from MEPi presented by Seki et al. [2019] reveals the frequent presence of energetic molecular (N2+, NO+ and/or O2+) ions in the ring current, not only during times of extreme geomagnetic activity, which is expected based on previous episodic observations, but also at times of moderate activities, which is rather surprising.

These observed molecular ions are believed to originate from the Earth’s ionosphere, where they are expected to undergo recombination to form a pair of neutral atoms within minutes of their creation. Therefore, their detection in the ring current provides a time tag for the maximum time available—and correspondingly minimum ion acceleration rate required—to extract a heavy ion from the ionosphere and energize it to ring current energies.

Coupled with our previous knowledge of thermal ion upwelling from Dynamic Explorer 1 (DE-1), Akebono, Polar and other satellites, the Arase results provide an important metric with which to evaluate large scale models of the Earth’s magnetosphere.

Citation: Seki, K., Keika, K., Kasahara, S., Yokota, S., Hori, T., Asamura, K., et al. [2019]. Statistical properties of molecular ions in the ring current observed by the Arase (ERG) satellite. Geophysical Research Letters, 46, 8643– 8651. https://doi.org/10.1029/2019GL084163

—Andrew Yau, Editor, Geophysical Research Letters

NOAA’s Acting Head Addresses Storm over Dorian Forecasts

Tue, 09/10/2019 - 20:11

“Weather should not be a partisan issue.”“Weather should not be a partisan issue,” Neil Jacobs, acting administrator for the National Oceanic and Atmospheric Administration (NOAA) said on 10 September, publicly addressing for the first time a controversy about the forecasting of Hurricane Dorian, according to a NOAA spokesperson.

The issue that has engulfed NOAA in political controversy began with President Donald Trump tweeting outdated information that Alabama was threatened by Hurricane Dorian. In response to the president’s tweets, the Birmingham, Ala., office of NOAA’s National Weather Service (NWS) stated that “Alabama will NOT see any impacts from #Dorian.”

A 6 September NOAA statement said that the hurricane forecasting provided to the president demonstrated that strong winds from the hurricane could have affected Alabama. That statement said, “The Birmingham National Weather Service’s Sunday morning tweet spoke in absolute terms that were inconsistent with probabilities from the best forecast products available at the time.”

A 9 September article in the New York Times reported that Secretary of Commerce Wilbur Ross threatened to fire top NOAA employees after the Birmingham office published its tweet. (The Department of Commerce is NOAA’s parent agency.)

A number of prominent scientists, including three former NOAA administrators, have expressed their concern that political appointees should not overrule scientists. David Titley, who formerly served in the chief operating officer position at NOAA, tweeted about the 6 September NOAA statement, “Perhaps the darkest day ever for @noaa leadership. Don’t know how they will ever look their workforce in the eye again. Moral cowardice.”

Jacobs Pledges Full Support to Weather Service

Speaking at the annual meeting of the National Weather Association in Huntsville, Ala., Jacobs addressed the controversy. “The weather service team has my full support and the support of the department,” he said. “I’ll do everything I can to support you and your critical mission to protect life and property of the American people.”

Jacobs said that the purpose of NOAA’s 6 September statement was to clarify the technical aspects of the potential impacts of Dorian. “What it did not say, however, is that we understand and fully support the good intent of the Birmingham weather office, which was to calm fears in support of public safety. I’m proud of the outstanding work performed by all of the weather forecast offices.”

“From now on, the National Weather Service should be at the table with emergency managers and FEMA at all briefings.”He added, “There is no pressure to change how you forecast risk into the future. No one’s job is under threat. Not mine. Not yours. The weather service team has my full support and the support of the department.”

Jacobs said that at one point, Alabama was in the hurricane forecast mix, as was the rest of the Southeast. He also said that the Trump administration “is committed” to the important mission of weather forecasting, including how forecasts are communicated.

One lesson he learned from the incident, Jacobs said, is that “from now on, the National Weather Service should be at the table with emergency managers and FEMA [Federal Emergency Management Agency] at all briefings. This is critically important. If we are going to be analyzing forecast output, we need somebody there who understands how to interpret it.”

Jacobs added that he hopes that with the current elevated interest in forecasting “will come elevated funding to overcome the challenges we face, whether it’s numerical weather prediction, high-performance computing, or dissemination.”

House Science Committee Pursues Issue

Also on Tuesday, Rep. Eddie Bernice Johnson (D-Texas), chair of the House Committee on Science, Space, and Technology, said that her committee is actively pursuing the Dorian forecast uproar.

“I am extremely disturbed by the directive that NOAA leadership sent on September 6, which threatens the integrity and public trust of weather forecasts at the peak of Hurricane season.”“I am extremely disturbed by the directive that NOAA leadership sent on September 6, which threatens the integrity and public trust of weather forecasts at the peak of Hurricane season. I am even more distressed to learn that political interference from the Secretary of Commerce may be behind the directive,” Johnson said in a statement.

Johnson added that the House Science Committee “will pursue this issue and we expect full cooperation from the Department of Commerce in our efforts. I would remind Department employees of the whistleblower protections afforded them by law. Any employees with information are welcome to share anonymously via the Committee Whistleblower Page.”

On 5 September, Johnson issued a statement expressing concern about President Trump holding an outdated forecast of Hurricane Dorian in a 4 September tweet issued by the White House. The map “appeared to have been modified to suggest a forecasted impact to Alabama.”

“In times of emergency, the American public need to have confidence in the information being provided by the White House, and misrepresentation of National Weather Service (NWS) forecasts is especially disturbing when it concerns an ongoing natural disaster that has already killed twenty people,” Johnson said.

Also on Tuesday, Sen. Jeanne Shaheen (D-N.H.), the ranking Democrat on a Senate committee that oversees funding for NOAA, called for an inspector general investigation into whether NOAA’s 6 September statement violated the agency’s scientific integrity code. “I believe that NOAA released this statement to defend the President’s position, while ignoring the best available science. This statement violates NOAA’s internal scientific integrity order,” Shaheen wrote in a letter.

On 9 September, several members of Congress, including Reps. Don Beyer (D-Va.) and Paul Tonko (D-N.Y.), called for Commerce Secretary Ross to resign.

—Randy Showstack (@RandyShowstack), Staff Writer

Altered Forecasts and Threatened Firings at the National Weather Service

Tue, 09/10/2019 - 14:56

The National Weather Service (NWS) has always been a model of scientific integrity, ensuring that weather science is not politically driven, regardless of the administration. But the recent misleading statements by President Donald Trump about a NWS hurricane forecast and cover-up actions by the National Oceanic and Atmospheric Administration (NOAA), its parent agency, have violated those norms.

The National Weather Service recognizes that its success is measured not solely by the accuracy of forecasts but, critically, by the societal response to those forecasts.The mission of the NWS is to provide weather, water, and climate data; forecasts and warnings for the protection of life and property; and enhancement of the national economy. Its reach is national—to every community in the United States. The goal is to achieve a weather-ready nation that is prepared for and responds to weather, water, and climate-dependent events. Perhaps most important, the NWS also recognizes that its success is measured not solely by the accuracy of forecasts but, critically, by the societal response to those forecasts.

Last week’s events related to the forecast path of Hurricane Dorian show the importance of societal impact. First, embarrassingly inaccurate and out-of-date statements, plus a chart with false information issued by President Trump, overrode the sound science of the forecast and sowed public confusion about the storm’s hazards. Then political appointees at NOAA, apparently under threat of firing by the secretary of commerce, criticized the Birmingham NWS office for accurately reassuring Alabama citizens that they were not in danger.

The political appointees twisted the facts to justify inaccurate statements made by the president. This is truly dangerous territory.To make their case, the political appointees twisted the facts to justify inaccurate statements made by the president. This is truly dangerous territory. It is beyond sad to see political appointees undermining the superb, life-saving work of NOAA’s talented and dedicated career servants and putting American communities at risk. The NWS did an excellent job in forecasting the track and strength of Hurricane Dorian and should be recognized for that.

Scientific integrity at a science agency like NOAA is at the core of its credibility. That is why NOAA has a comprehensive a Scientific Integrity Policy, designed to “strengthen widespread confidence—from scientists, to decision-makers, to the general public—in the quality, validity, and reliability of NOAA science.” The policy reflects the agency’s commitment to ensuring that NOAA’s science meets the highest standards of rigor and transparency. It includes principles aimed at preventing politics from interfering with the discovery, use, and communication of scientific information, and it has protocols to deal with violations of these standards. The actions by NOAA political appointees last week violated those standards and directly undermined the agency’s credibility.

NOAA’s political leaders’ criticism of the NWS Forecast Office in Birmingham, Ala., was a direct violation of core principles of NOAA’s Scientific Integrity Policy. The threatened firings by the secretary of commerce and subsequent actions by political leaders directly undermined the need for NOAA scientists to be open and transparent about their work. These actions mean that they are not free to speak to the media and the public about scientific and technical matters based on their official work.

Beyond violating policy, some of last week’s actions may well be criminal.Beyond violating policy, some of last week’s actions may well be criminal. Counterfeiting government weather forecasts has been a federal crime since 1894 [Pietruska, 2018]. That law was established to ensure that the best available forecasts were freely available. This policy has protected the public from harm. It’s a recognition that any manipulation of the official NWS forecast, whether it is for hurricanes or floods or any other weather event, misleads the public and could have disastrous effects. The private sector weather industry also depends on that policy and must be able to count on NOAA’s scientific integrity and apolitical posture. Last week’s foolish political actions weaken the foundation of this vibrant and growing economic enterprise.

To restore public trust in weather forecasts and warnings, every step should be taken to learn from this distortion of truth and breach of trust. We have called on Congress, NOAA, NWS, and the Department of Commerce leadership and the department’s inspector general to restore the public’s confidence in NWS weather forecasts and warnings by scrutinizing this breach of public trust. This includes implementing steps to prevent it from happening again and enforcing and reaffirming NOAA’s Scientific Integrity Policy.

Soil Moisture Drives Great Plains Cloud Formation

Tue, 09/10/2019 - 11:33

Towering cumulus clouds often loom over the southern Great Plains of the United States, particularly when warm, moist air rises from the soil during summer months. New research that tracked cumulus cloud formation over the course of a day demonstrates that much of the complex variation in the clouds derives from local variations in soil moisture, combined with pockets of cold air in the atmosphere.

Fast et al. used observational data from Oklahoma and Kansas collected on 30 August 2016 through the Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecosystems (HI-SCALE) campaign, which studied interactions between land, vegetation, and the atmosphere. During the morning, rainless, shallow clouds formed over southeast Oklahoma, then spread northwest into southern Kansas. By early afternoon, what was a fairly uniform field of clouds became more complex—some regions became cloudless, whereas others saw bigger, rain-laden clouds form.

The team attempted to recreate those patterns in a computer simulation, using an algorithm that tracks thousands of individual cumulus clouds at once. The researchers could faithfully represent the HI-SCALE observational data in the model only by including detailed soil moisture data from across the region. Later in the day, after about 1:00 p.m., regions of colder air surrounded by warm air, called cold pools, also played an important role, they found. The new study suggests that to accurately predict how clouds will behave, climate and weather models must account for soil conditions. (Journal of Advances in Modeling Earth Systems (JAMES), https://doi.org/10.1029/2019MS001727, 2019)

—Emily Underwood, Freelance Writer

Is the Northern Permafrost Zone a Source or a Sink for Carbon?

Tue, 09/10/2019 - 11:32

By now, the general public is well aware of greenhouse gases in Earth’s atmosphere and the overall warming effect that burning fossil fuels has on the world’s climate. Less publicized is the effect of a warming climate on the permanently frozen ground—permafrost—in the far northern regions of the world. And still less is known about how gases released by thawing permafrost soils could accelerate the very climate change that caused them to thaw in the first place.

Permafrost soils contain twice as much carbon as is currently present in the atmosphere, and the emission of just a fraction of permafrost carbon would strongly amplify the ongoing warming of the planet. Despite this worrying possibility, we presently lack the ability to detect changes in carbon emissions across the Arctic and boreal region in a timely manner.

A new initiative led by the Permafrost Carbon Network aims to resolve this shortcoming. This synthesis activity, supported in part by the Arctic Data Center, will develop a comprehensive repository for net carbon dioxide (CO2) flux data collected across the northern permafrost zone.

This project builds on the efforts of countless scientists, across decades, who weathered swarms of mosquitoes and harsh weather to make precise measurements of the carbon exchange of treeless tundra, boreal forests, and permafrost soils.This project builds on the efforts of countless scientists, across decades, who weathered swarms of mosquitoes and harsh weather to make precise measurements of the carbon exchange of treeless tundra, boreal forests, and permafrost soils. Although these measurements tell us a great deal about single sites, the larger picture remains much more elusive.

Previous efforts that synthesized this wealth of data disagree on whether the Arctic is presently a net sink or source of CO2 [Belshe et al., 2013; McGuire et al., 2012]. Although valuable insight has been gained, this basic question about the carbon balance of the permafrost zone remains unresolved.

The direction in which net CO2 exchange will develop with future warming is equally, if not more, uncertain. In general, warmer soils respire more CO2, and thawing permafrost releases carbon that can add to this effect. At the same time, warming also enhances the uptake of CO2 by plants, which at least partly compensates for the loss of soil carbon. Large interannual variations in these two opposing processes make it challenging to identify shifts in net CO2 exchange. Decadal time series, constructed from as many sites as possible, are necessary to determine trends for the entire permafrost zone.

A Sink of Data, a Source of Knowledge

To tackle these issues, we welcome flux observations from Arctic and boreal ecosystems in our data repository. For an essential, comparative perspective, we include data from ecosystems within and outside the permafrost zone. The evolving database will include measurements spanning 3 decades, with the intention to incorporate new observations as near to real time as possible. The fast response time makes it possible to report whether deviations from the historical baseline are occurring.

The scientific community is currently unable to communicate regional changes in permafrost carbon in the same way as for other components of Earth’s cryosphere.Such a database is long overdue. The scientific community is currently unable to communicate regional changes in permafrost carbon in the same way as for other components of Earth’s cryosphere. For example, the retreat of glaciers, melting of ice sheets, shrinking of sea ice, and increase in permafrost temperature are all well documented and regularly reported [e.g., Box et al., 2019]. Part of the reason for this difference in up-to-date information is an inability to detect permafrost carbon at the circumpolar scale using remote sensing technologies, and syntheses of site data occur sporadically rather than systematically.

The synthesis activity in our project differs in its scope from existing efforts such as FLUXNET, which has been highly effective at integrating measurements made with the eddy covariance technique. Eddy covariance tower data are considered the current gold standard because of their high temporal and landscape-scale coverage, but this technique will always be limited to fewer locations because it is cost intensive.

A fully instrumented eddy covariance tower at Scotty Creek Research Station near Fort Simpson, Northwest Territories, Canada, collects data over large spatial areas and long time spans to disentangle the drivers of net CO2 exchange and to understand regional differences. Credit: Manuel Helbig

In contrast, flux chambers are used to observe carbon exchange in many more locations but are temporally limited. The data they collect are not systematically archived in a central database. The goal of the new database is to compile biweekly, monthly, or seasonal aggregates of net CO2 flux data collected with both eddy covariance and flux chambers, which collectively allow a picture of the whole region to emerge, at timescales relevant to climate and model projections.

Bridging Time and Space

Initial analysis will reveal valuable insights in decadal trends of net CO2 exchange and the response to years with extreme temperatures or precipitation. To minimize uncertainties in these analyses, a number of hurdles involving such factors as spatial variation, fragmented time series, and the representativeness of the collected data need to be cleared. This is challenging because permafrost landscapes are highly diverse with distinct microtopography: Dry elevated areas and wet depressions alternate across short distances.

Surface wetness has a strong influence on carbon exchange. Soil respiration rates are generally lower under wet conditions because of the lack of oxygen in the soil, which is why wet ecosystems are often hot spots for CO2 uptake. The availability of water also controls the types of vegetation present: Dwarf shrubs are typically found in dry elevated areas, whereas sedges are common to wet areas. Sphagnum and other moss species also follow moisture gradients. These differences in ecosystem composition lead to varying rates of plant litter input and decomposition. Thus, the spatial distribution of soil carbon is strongly tied to the interplay of geomorphology, surface hydrology, and ecosystem composition.

Capturing the complexity of nature is a colossal task in itself, but the locations and times at which scientists have aimed to do so introduce additional challenges. High-latitude fieldwork has historically been concentrated around a few research stations in Scandinavia and Alaska, which has led to spatial biases where colder environments are poorly sampled [Virkkala et al., 2018]. An analysis of past trends in CO2 exchange, if done incorrectly, may be more representative of the North Slope in Alaska than the entire permafrost zone. This patchiness is clear from a recently launched mapping tool of northern flux stations (Figure 1).

Fig. 1. Locations for CO2 and methane flux measurements across the northern permafrost zone collected with eddy covariance (yellow) and chambers (blue). Metadata for these sites are accessible through an online mapping tool. Net CO2 flux data for our synthesis activity have been obtained for most of these sites.

Also, flux measurements have rarely been continuous in time because of financial and logistical constraints. Existing snapshots need to be stitched together while accounting for seasonal biases: Most fieldwork is concentrated in summer, even though the cold season can last up to 9 months. And nongrowing season emissions may be crucial in determining whether the northern permafrost zone is a net source of CO2.

Given these challenges of scale, we need sufficient metadata to place flux measurements from individual locations into a larger context. What was the water level, thaw depth, and soil temperature at the time of measurement? Which types of plants were present, and in what abundance? Furthermore, do the chamber flux measurements cover vegetation types that are representative of the larger region? We propose a consistent framework for metadata, which will make it possible to match flux measurements across space and time and to upscale them to the whole of the permafrost zone. Future steps may also include instituting a more automated procedure to incorporate publicly available metadata.

These soil cores, greater than 1 meter deep, were drilled from adjacent features of polygonal tundra on the North Slope of Alaska, and they provide essential information for carbon flux studies. The core on the left goes through an ice wedge and shows a thick, dark organic layer that overlies massive ground ice, indicating risk for surface subsidence. The core on the right comes from the center of a polygon and shows the deep accumulation of organic carbon that may be decomposed if the soil warms. To construct an accurate representation of carbon fluxes, it is essential to capture as much site metadata as possible, including incoming shortwave radiation, temperature, and precipitation, as well as vegetation composition and soil properties. Credit: Marguerite Mauritz

This database is a first step to further understanding of the permafrost carbon feedback. Methane and nitrous oxide (N2O) emissions and lateral (land-to-water) carbon losses are currently excluded. Measurements over lakes and rivers are also not considered. However, terrestrial CO2 emissions represent the bulk of the potential release of greenhouse gases from permafrost thaw, which is why the monumental challenge of capturing the state of the permafrost carbon pool needs to start there. Other synthesis efforts of methane and N2O are underway, and parallel analyses will provide more comprehensive insights.

Observing the Present to Predict the Future

Beyond our intent to better understand the natural system, this activity will also highlight the economic and societal value of maintaining a flux observation network across the permafrost zone. For example, the Paris Agreement aims to keep warming of the planet this century to well below 2°C, preferably below 1.5°C. Carbon release from permafrost may hamper the feasibility of achieving that goal, even though the likelihood of different warming scenarios is highly uncertain. This uncertainty has consequences for the accuracy of economic projections of the cost of climate change.

By acting as a benchmark, the flux database will lead to more realistic projections that will indicate which future scenarios are unlikely. Focusing on the most likely scenarios lowers costs by reducing the necessity for policy makers to prepare for all possible eventualities. An improved quantification of future permafrost carbon loss can therefore represent an economic benefit.

This database will be a major step in determining how the rapid changes in the Arctic may affect the permafrost carbon feedback. Many in the scientific community have already contributed, and we hope you will join us in this collective effort to deliver the most comprehensive and up-to-date view of the net CO2 exchange of the northern permafrost zone.

Acknowledgments

We thank the many researchers who have already contributed data and other input to expand our initial data sets. We also thank all workshop participants who helped put together the ideas and initial data for this synthesis. In particular, we thank Brandon Rogers for putting a lot of thought into our initial metadata format and Gerardo Celis for programming and data support. And we thank M. Goeckede, G. Celis, and M. Pallandt for their hard work in developing the carbon flux sites mapping tool shown in Figure 1. We acknowledge the Arctic Data Center for providing workshop funding, as well as the National Science Foundation’s collaborative research award (grant 1331083): Research, Synthesis, and Knowledge Transfer in a Changing Arctic: Science Support for the Study of Environmental Arctic Change. F.-J.W.P. received additional support from the Norwegian Research Council under grant agreement 274711 and from the Swedish Research Council under registration number 2017-05268.

Hydrological Footprint of Atmospheric Rivers on Land

Tue, 09/10/2019 - 11:30

Atmospheric rivers (ARs) are long narrow bands of intense poleward moisture transport originating from the tropics. They are responsible for a large fraction of heavy precipitation, snowmelt, and flooding events in the western United States. The connections between ARs and surface hydrology are important scientifically and societally, but a lack of observational data has limited systematic analysis and understanding.

Based on a long-term high-resolution climate simulation, Chen et al. [2019] offer one of the most comprehensive evaluations of land surface energy and hydrologic responses to ARs to date. Their study reveals the unique meteorological conditions of precipitation, air temperature, and radiation associated with ARs and quantifies their impacts on surface hydrological processes. The study highlights the intensification of snow ablation by ARs and the important role of ARs in the interannual variability and seasonal cycle of water resources in the western U.S.

This study lays the foundation for future studies on how climate change may affect the surface hydrologic responses to ARs.

Citation: Chen, X., Leung, L. R., Wigmosta, M., & Richmond, M. [2019]. Impact of atmospheric rivers on surface hydrological processes in western U.S. watersheds. Journal of Geophysical Research: Atmospheres, 124. https://doi.org/10.1029/2019JD030468

—Minghua Zhang, Editor in Chief, JGR: Atmospheres

Our Seismic Solar System

Tue, 09/10/2019 - 11:29

Earth experiences millions of earthquakes every year, most too small to be felt. It is the only planet known so far to have plate tectonics, and most of our earthquakes occur where the plates come together, split apart, or slide against each other.

But quakes, shakes, tremors, and vibrations are by no means confined to Earth. Scientists have used measurements of seismicity and tectonics, past or present, to learn all about what lies beneath the surfaces of planets and to infer their geologic histories.

Here’s a snapshot of our not-so-surprisingly seismic solar system.

 

The centerpiece of our solar system, the Sun, is a boiling ball of plasma that pulses and vibrates at different frequencies. The study of how vibrations travel through the Sun, called helioseismology, and through other stars, called asteroseismology, teaches us about the interior structure of stars. Below, you can listen to three of the Sun’s harmonic acoustic waves converted into human hearing range by the Stanford Solar Center. (The waves play separately and are then overlaid.)

https://eos.org/wp-content/uploads/2019/09/sun-3-modes-harmonics.wav

 

We learned a few years ago that Mercury is shrinking. A 2016 analysis of data from the now crashed Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) mission revealed small thrust fault scarps that cut across Mercury’s many craters. The placement of the small scarps suggests that our solar system’s smallest planet is tectonically active today because it’s shrinking.

 

Apollo 11 astronaut Buzz Aldrin deploys a seismometer in the Sea of Tranquility. Credit: NASA

Venus is a tectonic puzzle. Right now it has no tectonic plates—and, in fact, it may never have had them. It has many recognizable tectonic features on its surface like faults and folds, but those features may have come from other processes like mantle convection or volcanoes. We have not seen any venusquakes yet, but scientists speculate that we might be able to remotely detect them as their vibrations ripple through Venus’s thick atmosphere.

 

 

 

 

 

Apollo 11’s Passive Seismic Experiment was the first seismometer placed on the Moon. From it and subsequent Apollo seismometers we learned that the Moon experiences four types of moonquakes. The deep quakes from tidal stretching, vibrations from impacts, and thermal quakes from day-night temperature shifts are relatively harmless. Shallow, strong, and long-lasting quakes of unknown origin—the fourth kind—might affect future explorers.

 

A simulation displays seismic waves from a marsquake as they move through different layers of Mars’s interior. Credit: NASA/JPL-Caltech/ETH Zurich/Van Driel

Mars just recently joined the ranks of planets known to be seismically active. NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander placed a seismometer on Mars’s surface and measured its first marsquake in April 2019. After it kicked off the new scientific field of Martian seismology, InSight continued to detect quakes so small they’d be hidden within the background noise of Earth’s oceans.

 

 

 

 

 

Saturn has its own unique set of seismometers: its rings. “Some wave structures in Saturn’s rings are sensitive to the gravity field of Saturn,” the Planetary Society’s Emily Lakdawalla explained. Vibrations within Saturn will propagate into the rings as waves, ripples, and twists like an earthquake shaking piano strings. Recently, this kind of ring seismology let scientists pin down Saturn’s interior structure and measure the length of a Saturnian day for the first time. Below, fly above Saturn’s rings with this compilation of images from the Cassini spacecraft.

 

You don’t have to be a planet to have tectonics: Pluto is currently geologically active. Data from NASA’s New Horizons spacecraft when it flew through the Pluto system in 2014 revealed a complex set of geological features, including faults. There is no evidence for strike-slip faults or compressional tectonics, but it’s likely that Pluto’s surface is undergoing stress fractures as a liquid water ocean partially freezes and thaws beneath the icy crust.

—Kimberly M. S. Cartier (@AstroKimCartier), Staff Writer

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