The hydroxyl (OH) radical, a molecule made up of one hydrogen atom, one oxygen atom with a free (or unpaired) electron is one of the most reactive gases in the atmosphere and regularly breaks down other gases, effectively ending their lifetimes. In this way OH is the main check on the concentration of methane, a potent greenhouse gas that is second only to carbon dioxide in contributing to increasing global temperatures.

With the rise of methane emissions into the atmosphere, scientists historically thought that might cause the amount of hydroxyl radicals to be used up on the global scale and, as a result, extend methane’s lifetime, currently estimated to be nine years. However, in addition to looking globally at primary sources of OH and the amount of methane and other gases it breaks down, this new research takes into account secondary OH sources, recycling that happens after OH breaks down methane and reforms in the presence of other gases, which has been observed on regional scales before.

“OH concentrations are pretty stable over time,” said atmospheric chemist and lead author Julie Nicely at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “When OH reacts with methane it doesn’t necessarily go away in the presence of other gases, especially nitrogen oxides (NO and NO₂). The break down products of its reaction with methane react with NO or NO₂ to reform OH. So OH can recycle back into the atmosphere.”

Nitrogen oxides are one set of several gases that contribute to recycling OH back into the atmosphere, according to Nicely’s research, published in the Journal of Geophysical Research: Atmospheres. She and her colleagues used a computer model informed by satellite observations of various gases from 1980 to 2015 to simulate the possible sources for OH in the atmosphere. These include reactions with the aforementioned nitrogen oxides, water vapor and ozone. They also tested an unusual potential source of new OH: the enlargement of the tropical regions on Earth.

OH in the atmosphere also forms when ultraviolet sunlight reaches the lower atmosphere and reacts with water vapor (H₂O) and ozone (O₃) to form two OH molecules. Over the tropics, water vapor and ultraviolet sunlight are plentiful. The tropics, which span the region of Earth to either side of the equator, have shown some evidence of widening farther north and south of their current range, possibly due to rising temperatures affecting air circulation patterns. This means that the tropical region primed for creating OH will potentially increase over time, leading to a higher amount of OH in the atmosphere. This tropical widening process is slow, however, expanding only 0.5 to 1 degree in latitude every 10 years. But the small effect may still be important, according to Nicely.

She and her team found that, individually, the tropical widening effect and OH recycling through reactions with other gases each comprise a relatively small source of OH, but together they essentially replace the OH used up in the breaking down of methane.

“The absence of a trend in global OH is surprising,” said atmospheric chemist Tom Hanisco at Goddard who was not involved in the research. “Most models predict a ‘feedback effect’ between OH and methane. In the reaction of OH with methane, OH is also removed. The increase in NO₂ and other sources of OH, such as ozone, cancel out this expected effect.” But since this study looks at the past thirty-five years, it’s not guaranteed that as the atmosphere continues to evolve with global climate change that OH levels will continue to recycle in the same way into the future, he said.

Ultimately, Nicely views the results as a way to fine-tune and update the assumptions that are made by researchers and climate modelers who describe and predict how OH and methane interact throughout the atmosphere. “This could add clarification on the question of will methane concentrations continue rising in the future? Or will they level off, or perhaps even decrease? This is a major question regarding future climate that we really don’t know the answer to,” she said.

The study, “Recent Global Decline in Endorheic Basin Water Storage,” was carried out by a team of scientists from six countries and appears in the current issue of Nature Geoscience.

“Water resources are extremely limited in the continental hinterlands where streamflow does not reach the ocean. Scientifically, these regions are called endorheic basins,” said Jida Wang, a Kansas State University geographer and the study’s lead author.

“Over the past few decades, we have seen increasing evidence of perturbations to the endorheic water balance,” said Wang, an assistant professor of geography. “This includes, for example, the desiccating Aral Sea, the depleting Arabian aquifer and the retreating Eurasian glaciers. This evidence motivated us to ask: Is the total water storage across the global endorheic system, about one-fifth of the continental surface, undergoing a net decline?”

Using gravity observations from NASA/German Aerospace Center’s Gravity Recovery and Climate Experiment, or GRACE, satellites, Wang and his colleagues quantified a net water loss in global endorheic basins of approximately 100 billion tons of water per year since the start of the current millennium. This means a water mass equivalent to five Great Salt Lakes or three Lake Meads is gone every year from the arid endorheic regions.

Surprisingly, this amount of endorheic water loss is double the rate of concurrent water changes across the remaining landmass except Greenland and Antarctica, Wang said. Opposite to endorheic basins, the remaining regions are exorheic, meaning streamflow originating from these basins drains to the ocean. Exorheic basins account for most of the continental surface and are home to many of the world’s greatest rivers, such as the Nile, Amazon, Yangtze and Mississippi.

Wang noted that the signature of water storage changes in exorheic basins resembles some prominent oscillations of the climate system, such as El Niño and La Niña in multiyear cycles. However, the water loss in endorheic basins appears less responsive to such short-term natural variability. This contrast may suggest a profound impact of longer-term climate conditions and direct human water management, such as river diversion, damming and groundwater withdrawal, on the water balance in the dry hinterlands.

This endorheic water loss has dual ramifications, according to the researchers. Not only does it aggravate water stress in the arid endorheic regions, but it could also contribute to a significant factor of global environmental concern: sea level rise. Sea level rise is a result of two main causes: thermal expansion of sea water as a result of increased global temperature, and additional water mass to the ocean.

“The hydrosphere is mass conserved,” said Chunqiao Song, researcher with the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, and a co-lead author of the study. “When water storage in endorheic basins is in deficit, the reduced water mass doesn’t disappear. It was reallocated chiefly through vapor flux to the exorheic system. Once this water is no longer landlocked, it has the potential to affect the sea level budget.”

Despite an observation period of 14 years, the endorheic water loss equals an additional sea level rise of 4 millimeters, the study found. The researchers said this impact is nontrivial. It accounts for approximately 10 percent of the observed sea level rise during the same period; compares to nearly half of the concurrent loss in mountain glaciers, excluding Greenland and Antarctica; and matches the entire contribution of global groundwater consumption.

“We are not saying the recent endorheic water loss has completely ended up in the ocean,” said Yoshihide Wada, deputy director of the water program at the International Institute for Applied Systems Analysis in Austria and a co-author of the study. “Instead, we are showing a perspective of how substantial the recent endorheic water loss has been. If it persists, such as beyond the decadal timescale, the water surplus added to the exorheic system may signify an important source of sea level rise.”

By synergizing multi-mission satellite observations and hydrological modeling, Wang and his colleagues attributed this global endorheic water loss to comparable contributions from the surface — such as lakes, reservoirs and glaciers — as well as soil moisture and aquifers.

“Such comparable losses are, however, an aggregation of distinct regional variations,” Wang said. “In endorheic Central Eurasia, for instance, about half of the water loss came from the surface, particularly large terminal lakes such as the Aral Sea, the Caspian Sea and Lake Urmia, and retreating glaciers in High Mountain Asia.”

While glacial retreat was a response to warming temperature, water losses in the terminal lakes were a combined result of meteorological droughts and long-term water diversions from the feeding rivers.

The net water loss in endorheic Sahara and Arabia, on the other hand, was dominated by unsustainable groundwater withdrawal, according to the researchers. In endorheic North America, including the Great Basin of the U.S., a drought-induced soil moisture loss was likely responsible for most of the regional water loss. Despite a lesser extent, the surface water loss in the Great Salt Lake and the Salton Sea was at a substantial rate of 300 million tons per year, which was partially induced by mineral mining and diversion-based irrigation.

“The water losses from the world’s endorheic basins are yet another example of how climate change is further drying the already dry arid and semi-arid regions of the globe. Meanwhile, human activities such as groundwater depletion are significantly accelerating this drying,” said Jay Famiglietti, director of the Global Institute of Water Security, Canada 150 research chair in hydrology and remote sensing at the University of Saskatchewan, Canada and co-author of the study.

Wang said the team wants to convey three takeaway messages from their research.

“First, water storage in the endorheic system, albeit limited in total mass, can dominate the water storage trend in the entire land surface during at least decadal timescales,” Wang said. “Second, the recent endorheic water loss is less sensitive to natural variability of the climate system, suggesting a possible response to longer-term climate conditions and human water management.

“Third, such a water loss in the endorheic system has dual ramifications, both to regional water sustainability and to global sea level rise,” he said. “These messages highlight the underrated importance of endorheic basins in the water cycle and the need for an improved understanding of water storage changes in the global hinterlands.”

In the interim, stalwart practitioners of Jedi ways and other Force-sensitive beings can look to the small screen and thank Virginia Tech researchers for a recently developed virtual reality technique called Force Push.

Force Push gives its users the ability to move faraway objects with Yoda-like calm, nuance, and focus using an approach for remote object manipulation in VR.

“You basically push the object in the direction you want it to move to, just like in Star Wars when the Jedi masters try to move an object that’s placed remotely, they can push or pull it,” said Run Yu, Ph.D. candidate in the Department of Computer Science and the Institute for Creativity, Technology, and the Arts. Yu is first author on the recently published article in Frontiers in ICT detailing the research.

It’s as simple as using subtle hand gestures to push, pull, or twirl objects. Users employ their bare hands using a natural gesture-to-action mapping for object manipulation in a VR setting.

“We wanted to try and do this without any device, just using your hands, and also do it with gestures in a way that’s more playful,” said Doug Bowman, the Frank J. Maher Professor of Computer Science and director of the Center for Human Computer Interaction.

Force Push provides a more physical, nuanced experience than traditional hand controllers allow in VR. It responds to the speed and magnitude of hand gestures to accelerate or decelerate objects in a way that users can understand intuitively.

The ability to respond to nuanced hand movement is due to the technique’s novel physics-driven algorithms. Dynamically mapping rich features of input gestures to properties of physics-based simulation made the interface controllable in most cases. With Force Push, it’s just as easy for users to apply the gentlest of nudges to an object as it is to throw a heavy object across the room. The researchers also believe the physics-based technique makes Force Push more plausible, so that users have a “realistic” experience of these magical powers.

To perform user experiments the team used an Oculus Rift CV1 for display and a Leap Motion was applied for hand tracking. The virtual environment was developed in the Unity game engine, and the native physics engine of Unity was used to drive the physics-based simulation of the Force Push interface.

“Every week we kind of tweak something different in order to make the experience feel right,” said Bowman. “But now it feels really cool.”

Story Source:

Materials provided by Virginia Tech. Original written by Amy Loeffler. Note: Content may be edited for style and length.

Results show that increasing nighttime levels of artificial, outdoor light exposure, stratified by quartile, were associated with an increased prevalence of hypnotic prescriptions and daily dose intake. Furthermore, older adults exposed to higher levels of artificial, outdoor light at night were more likely to use hypnotic drugs for longer periods or higher daily dosages.

“This study observed a significant association between the intensity of outdoor, artificial, nighttime lighting and the prevalence of insomnia as indicated by hypnotic agent prescriptions for older adults in South Korea,” said Kyoung-bok Min, PhD, an associate professor in the Department of Occupational and Environmental Medicine at Seoul National University College of Medicine in South Korea. “Our results are supportive data that outdoor, artificial, nighttime light could be linked to sleep deprivation among those while inside the house.”

The study results are published in the Nov. 15 issue of the Journal of Clinical Sleep Medicine.

According to the American Academy of Sleep Medicine, insomnia can involve struggling to fall asleep, having trouble maintaining sleep, or waking up too early. A variety of environmental factors, including excessive noise or light and extreme temperatures, will disrupt the sleep of most individuals.

The authors reported that the inappropriate or excessive use of artificial, outdoor light at night, referred to as “light pollution,” has emerged as a novel environmental factor linked to human health. Research has shown that artificial nighttime lighting, whether indoor or outdoor, induces disruption of circadian rhythms, potentially leading to metabolic and chronic diseases, including cancer, diabetes, obesity and depression.

The study used data from the 2002-2013 National Health Insurance Service-National Sample Cohort (NHIS-NSC), a population-based cohort in South Korea. The final study sample, after excluding those with a diagnosed sleep disorder, comprised 52,027 adults who were 60 years of age or older. About 60 percent of participants were female.

Light exposure was based on satellite data provided by the National Centers for Environmental Information. The estimated light pollution level in each administrative district was matched with individuals’ residential districts to determine an individual exposure level.

Usage data for two hypnotic drugs, zolpidem and triazolam, were extracted from health insurance records. About 22 percent of study participants had prescriptions for hypnotic drugs.

Min added that public health officials seem to be less concerned with light pollution than with other environmental pollutants. However, this study strengthens the potential link between light pollution and adverse health consequences.

“Given the recent scientific evidence including our results, bright outdoor lighting may be a novel risk factor for prescribing hypnotic drugs,” Min said.

The authors noted that more studies and public policy initiatives are needed to define and minimize the adverse effects of light pollution on human health.

For a month’s time, Ny-Ålesund will be home to the rocket team behind NASA’s VISIONS-2 mission, short for Visualizing Ion Outflow via Neutral Atom Sensing-2. They have ventured to this extreme place for an up-close look at atmospheric escape, the process whereby Earth is slowly leaking its atmosphere into space. Understanding atmospheric escape on Earth has applications all over the Universe — from predicting which far off planets might be habitable, to piecing together how Mars became the desolate, exposed landscape it is today. VISIONS-2 is scheduled to launch no earlier than Dec. 4, 2018.

Led by Doug Rowland of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, VISIONS-2 is a sounding rocket mission, a type of suborbital rocket that makes brief, targeted flights into space before falling back to Earth just a few minutes later. Sounding rockets are unique among scientific spacecraft for their superior dexterity: They can be carted to remote locations, where they are aimed and shot into short-lived events — like the sudden formation of the aurora borealis — at a moment’s notice.

The aurora borealis is of keen interest to the VISIONS-2 team, but not just for its otherworldly glow. The aurora play are fundamental drivers in the process of atmospheric escape, whereby planets, including Earth, gradually leak their atmosphere into space.

“The Earth is losing weight,” said Thomas Moore, a Goddard space physicist who specializes in atmospheric escape. “There have been enough observations to know that anywhere from a hundred to several hundred tons of atmosphere are going into space every day.”

(Not to worry — at that rate, Moore estimates, Earth will retain its atmosphere for a billion or so years.)

We’ve suspected that Earth was losing atmosphere since at least 1904, when Sir James Jeans first published his work The Dynamical Theory of Gases, laying the theoretical foundations for atmospheric escape. But there’s one element draining away that still presents a mystery. Scientists had long thought that oxygen, weighing in at 16 times the mass of hydrogen, was too heavy to escape Earth’s gravity.

“To escape Earth, oxygen would require something like 100 times the energy that it typically has,” said Rowland, the mission’s principal investigator. “Only the tiniest fraction should ever make it.” But when scientists finally went up and looked in the ’60s and ’70s, that’s not what they found. In fact, near-Earth space is teeming with much more Earth-borne oxygen than anyone had expected.

“But how did it get up there? You need processes that energize that oxygen enough to escape,” said Rowland.

The aurora, it turns out, is one such process. The aurora are formed when energetic electrons, accelerated in the electric and magnetic fields in near-Earth space, crash into and excite atmospheric gases, which emit bright hues of red, green, and yellow as they relax back to a lower energy state. But these unruly electrons also create a cascade of havoc in the process, including driving electric currents that heat the upper atmosphere in splotchy patches. In some cases, that heating is sufficient to give stray oxygen atoms enough energy to escape. “It’s like putting a heating element into your soup — eventually, it’s going to start boiling,” said Rowland.

VISIONS-1, the current mission’s precursor, launched from the Poker Flat Research Range in Alaska in 2013, where they studied oxygen outflow from aurora that form on Earth’s night side, the part of the planet that is temporarily pointed away from the Sun. For the VISIONS-2 mission, the team will travel to a unique part of the globe where dayside aurora can be found.

Once a day, Svalbard passes under an unusual feature in Earth’s magnetosphere known as the polar cusp. The polar cusps form at both the North and South poles on the Sun-facing side of the planet, and they are the only places where particles from the solar wind can stream directly into our atmosphere. The cusps are like magnetic bridges between Earth and space, where energetic electrons from the Sun crash into atmospheric particles and create a dayside aurora.

VISIONS-2 will fly two rockets into the northern polar cusp, where it will use an imaging technique to map oxygen outflow from the aurora. Using this technique, VISIONS-2 takes a different approach from many other missions, which attempt to combine data from many outflow events. Instead, VISIONS-2 hopes to acquire a great deal of data about a single oxygen outflow event. Not all outflow events are the same, but understanding one in great detail would provide significant scientific value.

“It’s like if you’re trying to study tornados, you could just measure the winds as various tornadoes fly by at different distances from your house,” said Rowland. “You’d get a picture of what an ‘average’ tornado looks like. What we want to do instead is to comprehensively observe one tornado, to understand how it works in detail.”

VISIONS-2 is all about checking whether and how the process for the heating and energizing of oxygen on the dayside aurora — within the polar cusp — is the same as those discovered on the night side. It’s far from a foregone conclusion, as the dayside and nightside display some marked differences.

“The ion outflow in the cusp is more steady and lower energy, while that in the nightside is more bursty and can be higher energy,” Rowland explained. “In addition, the environment is different between the cusp and nightside, so we’re looking for commonalities and differences.”

VISIONS-2 won’t be the only rocket to launch from this remote location: It is the first of nine sounding rockets launching over the next 14 months as part of the Grand Challenge Initiative — Cusp. Drawing researchers from the United States, Canada, Norway, the UK and Japan, the Grand Challenge is an international collaboration to explore the northern polar cusp, hopefully cracking the code of this unusual portal between Earth and space.

VISIONS-2 is scheduled to launch from Ny-Ålesund, Svalbard rocket range in December 2018. The launch window extends from December 4 through 18.