Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: AGU Advances
In low Earth orbit (typically below about 700 kilometers altitude), atmospheric drag is the primary source of uncertainty when predicting the trajectories of satellites. These prediction errors largely arise from limitations and inaccuracies in the models used to estimate the density of the upper atmosphere, particularly within the thermosphere.
Mutschler et al. [2026] introduce a new met
In low Earth orbit (typically below about 700 kilometers altitude), atmospheric drag is the primary source of uncertainty when predicting the trajectories of satellites. These prediction errors largely arise from limitations and inaccuracies in the models used to estimate the density of the upper atmosphere, particularly within the thermosphere.
Mutschler et al. [2026] introduce a new method for estimating atmospheric density along the path of an individual satellite by using Energy Dissipation Rates (EDRs). The derived single-satellite density measurements provide valuable insight into variations in thermospheric density and can help characterize how the upper atmosphere responds to disturbances such as geomagnetic storms. Incorporating these observations can contribute to ultimately improving the accuracy of satellite orbit predictions.
Effective density and Space Force effective density estimated by the Kosmos 1508 satellite (plotted on the right-hand y axes) compared to estimates from satellites Swarm-A and Swarm-C (plotted on the left-hand y-axes). Credit: Mutschler et al. [2026], Figure 17a
Citation: Mutschler, S., Pilinski, M., Zesta, E., Oliveira, D. M., Delano, K., Garcia-Sage, K., & Tobiska, W. K. (2026). First results of a new inversion tool for thermospheric neutral mass density computations during severe geomagnetic storms. AGU Advances, 7, e2025AV002079. https://doi.org/10.1029/2025AV002079
Editors’ Vox is a blog from AGU’s Publications Department.
Explosive volcanic eruptions inject gases and ash into the atmosphere, posing major hazards for human health, infrastructure, and aviation. A new article in Reviews of Geophysics examines recent advances in estimating Eruption Source Parameters (ESPs), the key conditions at the volcanic vent that are a necessity for modeling the behavior of volcanic plumes. Here, we asked the authors to explain what ESPs are, what technologies are us
Explosive volcanic eruptions inject gases and ash into the atmosphere, posing major hazards for human health, infrastructure, and aviation. A new article in Reviews of Geophysics examines recent advances in estimating Eruption Source Parameters (ESPs), the key conditions at the volcanic vent that are a necessity for modeling the behavior of volcanic plumes. Here, we asked the authors to explain what ESPs are, what technologies are used to observe eruptions, and which scientific challenges and future research directions remain for improving volcanic plume monitoring and modeling.
In simple terms, what are Eruption Source Parameters?
Eruption Source Parameters (ESPs) describe the key conditions at the volcanic vent during an eruption.
Eruption Source Parameters (ESPs) describe the key conditions at the volcanic vent during an eruption, such as the mass eruption rate, exit velocity, temperature, and particle size distribution. These parameters define how material is injected into the atmosphere and are essential inputs for models that simulate plume rise and subsequent dispersal of volcanic gases and ash in the atmosphere. In simple terms, ESPs represent the boundary conditions that control the behavior of volcanic plumes. Because they cannot usually be measured during an eruption, they must be estimated from indirect observations and models, which introduces significant uncertainty.
Why is it important to understand how volcanic ash and gases disperse after an eruption?
Volcanic ash and gases can travel long distances and affect aviation safety, human health, infrastructure, and even climate. Fine ash particles are particularly hazardous for aircrafts, while ash fallout can disrupt communities and critical services on the ground. Gas emissions may also impact air quality and alter the atmospheric radiative budget. Understanding volcanic dispersion is therefore essential for forecasting the movement of volcanic clouds and issuing timely warnings. Reliable forecasts support risk mitigation strategies and enable more effective responses by civil protection agencies and aviation authorities.
What technologies are used to observe volcanic plumes?
Volcanic plumes are observed using a combination of satellite, ground-based, and, more rarely, airborne measurements. Satellite observations are crucial for tracking ash and gas clouds over large spatial scales and in near real time. Ground-based instruments, such as radar, cameras, and infrasound sensors, provide detailed information on plume dynamics close to the source. Increasingly, these observations are integrated with numerical models to infer eruption conditions. The combination of multiple data streams is essential for constraining ESPs and improving the reliability of plume simulations.
What are some of the recent advances in estimating Eruption Source Parameters?
Recent advances have focused on combining observations with numerical models to better constrain ESPs. Multi-sensor approaches, data inversion techniques, and improved plume models have significantly enhanced our ability to estimate eruption rates and plume dynamics. At the same time, high-resolution computational fluid dynamics (CFD) simulations provide deeper insights into the complex fluid dynamic processes governing plume behavior. However, these models are computationally expensive and unsuitable for real-time applications, highlighting the need for approaches that bridge the gap between physical realism and operational efficiency.
What strategies do you propose in your review to improve Eruption Source Parameters estimation?
A central contribution of this review is the proposal of a new class of operational models for volcanic plumes.
A central contribution of this review is the proposal of a new class of operational models for volcanic plumes. These models integrate the physical realism of high-fidelity CFD simulations with the efficiency of simplified models used in forecasting. In particular, the review highlights the potential of artificial intelligence and machine learning techniques to “learn” from CFD results and optimally calibrate the key variables controlling plume dynamics. This hybrid approach allows complex physical processes to be represented in a computationally efficient framework, making it suitable for real-time applications while retaining improved accuracy.
How does improved volcanic plume monitoring lead to more effective volcanic hazard assessment?
Improved monitoring leads to more accurate estimates of ESPs, which directly translate into better forecasts of plume rise and ash dispersion. This reduces uncertainty in hazard assessments and supports more reliable decision-making. For example, more accurate forecasts can help aviation authorities minimize disruptions while maintaining safety and enable civil protection agencies to issue targeted warnings. Ultimately, better integration of observations and models enhances the capacity to respond effectively during eruptions and to mitigate their societal and economic impacts.
What are the remaining questions or knowledge gaps where additional research is needed?
Further research is needed to improve the coupling between observations, physics-based models, and data-driven approaches.
Despite progress, significant challenges remain. ESPs are still difficult to constrain in real time, and uncertainties in both observations and models propagate into forecasts. The integration of diverse data sources is not yet fully optimized, and different estimation methods can yield inconsistent results. Further research is needed to improve the coupling between observations, physics-based models, and data-driven approaches. In particular, developing robust hybrid frameworks that combine CFD, simplified models, and machine learning represents a key direction for advancing both scientific understanding and operational forecasting.
Editor’s Note: It is the policy of AGU Publications to invite the authors of articles published in Reviews of Geophysics to write a summary for Eos Editors’ Vox.
A hole in the Montreal Protocol could delay the recovery of Earth’s ozone layer by about 7 years. New research found that the use of ozone-depleting substances used as feedstocks—chemicals used in the making of other chemicals—has not waned over time. In fact, their use has increased since the treaty’s adoption in 1987.
“The Montreal Protocol is such a success story that these ozone-harming sources are becoming relevant. A few decades ago, they were drowned out.”
“The Montreal Protocol is
A hole in the Montreal Protocol could delay the recovery of Earth’s ozone layer by about 7 years. New research found that the use of ozone-depleting substances used as feedstocks—chemicals used in the making of other chemicals—has not waned over time. In fact, their use has increased since the treaty’s adoption in 1987.
“The Montreal Protocol is such a success story that these ozone-harming sources are becoming relevant. A few decades ago, they were drowned out.”
“The Montreal Protocol is such a success story that these ozone-harming sources are becoming relevant. A few decades ago, they were drowned out,” said Luke Western, who researches greenhouse gases and ozone-depleting substances at the Massachusetts Institute of Technology. Western is a coauthor of a new study on the findings published in Nature Communications.
Almost 40 years ago, the Montreal Protocol banned the production and consumption of almost 100 long-lived gases that harm Earth’s ozone layer, such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), then largely used as coolants in refrigerators and air conditioners. These uses were the primary problem that needed to be solved and were the Montreal Protocol’s main target, Western explained.
However, ozone-depleting substances used in the production of other chemicals—including CFCs themselves—had so little impact at the time that they were not included in the ban. Only about 0.5% of feedstock chemicals, such as carbon tetrachloride (used in the making of some CFCs and a by-product of the manufacture of plastics like polyvinyl chloride, or PVC), were emitted into the atmosphere. With the production and use of the most prevalent ozone-harming gases banned, scientists thought the use of feedstocks such as carbon tetrachloride would die out over time.
However, not only did the die-out not happen, but the use of ozone-depleting substances as feedstock actually increased by 163% between 2000 and 2024. Western and his team found that associated emissions increased as well: Now, about 3.6% of these ozone-depleting feedstock chemicals are leaking into the atmosphere. The increase comes partly from their use in producing the non-ozone-depleting gases that replaced HCFCs and CFCs after the Montreal Protocol went into force.
“It’s almost the same as charging your electric car with fossil fuel–based energy.”
“This is quite ironic,” Western said. “It’s almost the same as charging your electric car with fossil fuel–based energy.”
If maintained at current levels, these emissions could delay full recovery of Earth’s ozone layer by anywhere from 6 to 11 years. Currently, recovery to 1980 levels is expected by 2040 for most of the world, by 2045 over the Arctic, and by 2066 over Antarctica, according to the World Meteorological Organization.
Filling a Gap
To estimate feedstock emissions, the researchers used datasets from the Advanced Global Atmospheric Gases Experiment (AGAGE) and NOAA containing information on about 50 chemicals from 1978 to 2023. The team used these data to model feedstock production and consumption between 2025 and 2034 and then between 2035 and 2100 for business-as-usual and low-emission scenarios.
When measured from now until the end of this century, feedstock emissions in the models tended to stabilize, but the real problem could be in the short and medium terms, the study suggested. Under a business-as-usual scenario, the production of some chemicals, such as methyl chloroform (used in solvents and found in household cleaners), is projected to decrease by 6% per year until 2050. But others, such as halon 1301 (used in the making of insecticides and pharmaceuticals), are set to increase (in halon 1301’s case, by 4% a year until 2050). With the estimates at hand, the team modeled feedstock emissions and their potential effect on the ozone layer.
“This is a very important study because it addresses several questions that remained open not just in the Montreal Protocol, but in research on the ozone layer recovery in general,” said Marco Aurélio Franco, an atmospheric sciences researcher at the University of São Paulo in Brazil.
Franco, who did not take part in the study, said research like this is fundamental to improving estimates for atmospheric chemistry and physics models. After all, some feedstock chemicals, including carbon tetrachloride—whose production is set to increase by 4% a year through 2034—are also greenhouse gases.
Carbon tetrachloride, Franco pointed out, acts differently depending on where it is in the atmosphere. In the troposphere, Earth’s lowest atmospheric layer, the substance traps heat by reflecting infrared radiation back to Earth. At this level, carbon tetrachloride is still stable. But any amount of the substance that reaches the atmosphere’s next layer, the stratosphere, wreaks havoc on the ozone layer. “Ultraviolet radiation is able to break carbon tetrachloride, liberating chlorine,” Franco said. “Chlorine then breaks ozone molecules in a chain reaction. It’s the same mechanism as CFCs.”
The world, said Franco, needs to walk the last mile in refraining from producing and using ozone-depleting substances as feedstock, as we still need to understand their long-term effects. “These [feedstock emission] estimates could be appended to the Montreal Protocol, which proved to be a great success. We need to incorporate them into emission reports and atmospheric models. These emissions should not be neglected,” he said.
Citation: Rodrigues, M. (2026), Repairing the ozone layer may take longer than expected, Eos, 107, https://doi.org/10.1029/2026EO260175. Published on 29 May 2026.
Source: Water Resources Research
Evapotranspiration is a critical link between water, energy, and carbon. Scientists need to understand it well to accurately predict weather, droughts, streamflows, and even carbon emissions.
Eddy covariance towers, which measure changes in the atmosphere, are one of the primary ways that scientists measure evapotranspiration in an ecosystem. But these measurements often have a problem with energy imbalance, in which the measured fluxes of sensible heat an
Evapotranspiration is a critical link between water, energy, and carbon. Scientists need to understand it well to accurately predict weather, droughts, streamflows, and even carbon emissions.
Eddy covariance towers, which measure changes in the atmosphere, are one of the primary ways that scientists measure evapotranspiration in an ecosystem. But these measurements often have a problem with energy imbalance, in which the measured fluxes of sensible heat and latent heat add up to less than they should. (Sensible heat refers to measurable temperature changes occurring via conduction or convection, whereas latent heat refers to water in the atmosphere changing phases.) There’s something missing—up to 30% of the system’s energy—in the math, and that can cause problems for later uses of the measurements, from forecasts to climate policies.
Scientists can adjust evapotranspiration measurements to try to correct for this problem, but a commonly used method to do so assumes that the Bowen ratio, or the ratio between sensible and latent heat, remains constant. However, this assumption may be flawed.
Raghav and Kumar present a new way of tackling this old problem without making assumptions about the Bowen ratio. It’s based on water use efficiency, which is how effectively plants use water to produce biomass.
The method first uses a suite of data from an eddy covariance tower to estimate evapotranspiration and energy balance through time. Then it derives the underlying water use efficiency potential while accounting for the influence of atmospheric dryness. In general, for a given vegetation type, this potential underlying efficiency is considered to be relatively stable over a growing season. The statistically smoothed potential underlying water use efficiencies is then compared to reference values derived during periods when the energy balance is well constrained. The ratio of the two is then used to correct evapotranspiration.
The new method is more consistent and more tied to the physics of plant physiology than current methods when results from each are compared, the authors found.
The new method is appropriate for use with any eddy covariance tower location or dataset because the authors used data from more than 250 towers around the world, in a range of ecosystem and climate types, to build their approach. However, they add, it may be less reliable in environments where evaporation dominates transpiration, such as wetlands. Nevertheless, the authors say, this work marks an important advance in measuring evapotranspiration, with broad implications for water management, agriculture, and adapting to climate extremes and drought. (Water Resources Research, https://doi.org/10.1029/2025WR042766, 2026)
Citation: Dzombak, R. (2026), Improving eddy tower evapotranspiration estimates, Eos, 107, https://doi.org/10.1029/2026EO260163. Published on 20 May 2026.
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: AGU Advances
The albedo change of marine clouds is achieved by targeted additions of aerosols, and in particular, sea salt. To assess the viability of Marine Cloud Brightening (MCB) requires a fundamental understanding of the impact of aerosols on cloud evolution and properties, and on the cloud environment.
Doherty et al. [2026] propose a framework for studying MCB across scales. This includes small-
The albedo change of marine clouds is achieved by targeted additions of aerosols, and in particular, sea salt. To assess the viability of Marine Cloud Brightening (MCB) requires a fundamental understanding of the impact of aerosols on cloud evolution and properties, and on the cloud environment.
Doherty et al. [2026] propose a framework for studying MCB across scales. This includes small- to large-scale studies aimed at systematically characterizing the life-cycle of aerosols and the diurnal cycle of cloud processes, how these change with the magnitude, duration and type of aerosol applied, and monitoring potential harmful direct or indirect consequences of aerosol injection, such as regional changes in temperature or precipitation.
Possible configuration for a Stage III study for measuring local scale cloud responses to a single plume of generated sea salt aerosol sized for marine cloud brightening. Credit: Doherty et al. [2026], Figure 4
Citation: Doherty, S. J., Diamond, M. S., Wood, R., & Hirasawa, H. (2026). Defining scales of field studies and experiments to assess marine cloud brightening. AGU Advances,7, e2025AV001939. https://doi.org/10.1029/2025AV001939
Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.
A Colorado judge has granted a preliminary injunction to the University Corporation for Atmospheric Research (UCAR). The move temporarily blocks the federal government from moving forward with one part of its effort to dismantle UCAR’s National Center for Atmospheric Research (NCAR) by transferring stewardship of a
Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.
A Colorado judge has granted a preliminary injunction to the University Corporation for Atmospheric Research (UCAR). The move temporarily blocks the federal government from moving forward with one part of its effort to dismantle UCAR’s National Center for Atmospheric Research (NCAR) by transferring stewardship of a state-of-the-art supercomputing facility.
Together, UCAR—a nonprofit consortium of universities and colleges—and the National Science Foundation (NSF) operate and maintain the NCAR-Wyoming Supercomputing Center (NWSC) in Cheyenne, Wyo. The facility provides scientists with enormous computational power necessary to run sophisticated analyses of weather, climate, and other Earth systems.
In February, as another step in a chain of actions taken to dismantle NCAR, the NSF informed UCAR and NCAR that it would transfer management and operations of NWSC to a third-party operator.
In turn, UCAR filed a lawsuitalleging that the action violated federal law under the Administrative Procedure Act (APA). To halt NSF’s action under the act, the agency’s attempt to remove UCAR’s stewardship of the facility must be shown to be “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.”
Judge Richard Brooke Jackson of the U.S. District Court for the District of Colorado wrote in a 1 June court order that the action was both arbitrary and capricious “for at least two reasons.” First, NSF didn’t offer an explanation for its decision, and second, it didn’t follow an outlined process to consider public feedback.
The decision means that UCAR will temporarily retain its stewardship of NWSC.
“NSF’s failure to provide any explanation for its decision—let alone a reasonable one—thwarts meaningful judicial review and renders the challenged action arbitrary and capricious,” Jackson wrote.
He went on to note that efforts to transfer stewardship of UCAR assets, including the supercomputing center, to other institutions, pose the risk of “irreparable harm” to UCAR. One of the chief harms would be brain drain, the judge noted multiple times, writing that “UCAR cannot easily replace employees with the level of education, specialized training, and institutional knowledge necessary to operate and maintain the NWSC’s ‘highly integrated, high-performance supercomputing system.'”
In addition to brain drain, Jackson cited financial injuries to UCAR that would be “difficult, if not impossible” to quantify, as well as an overall threat to the consortium’s mission.
“Any degradation in forecasting, modeling, or related scientific capabilities carries real-world consequences, including potential harm to property and human life. Given those stakes, the public interest strongly favors maintaining the status quo unless and until NSF demonstrates that its transfer decision complies with the APA,” he concluded.
In a statement posted to the UCAR website, the consortium’s interim president, Eric Barron, said UCAR was pleased that Judge Jackson recognized how harmful the proposed transfer would be for the the nation’s scientific enterprise.
“UCAR’s top priority is to advance Earth system science in service to society,” he wrote. “Today’s decision ensures that the NWSC will be able to continue its vital work on behalf of the United States and its stakeholders without interruption.”
These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org.
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Advances in Modeling Earth Systems
The purpose of atmospheric data assimilation is to obtain a 3-dimensional gridded representation of the fields of the atmospheric state variables (temperature, wind, pressure, etc.) for a specific time based on atmospheric observations. The product of data assimilation, called analysis, can be used to prepare weather maps and to start model-based weather forec
Source: Journal of Advances in Modeling Earth Systems
The purpose of atmospheric data assimilation is to obtain a 3-dimensional gridded representation of the fields of the atmospheric state variables (temperature, wind, pressure, etc.) for a specific time based on atmospheric observations. The product of data assimilation, called analysis, can be used to prepare weather maps and to start model-based weather forecasts. Analyses collected over a long period of time can also be used for research and to monitor variability and changes in the climate.
The main challenges of data assimilation are that observations are not collocated with the grid-points of the analysis, and most observations do not observe the variables of interest directly and have errors. For example, satellite-based observations, which form the bulk of the operationally assimilated observations, measure the intensity of electro-magnetic waves at the top of the atmosphere; a physical quantity that depends on the atmospheric state in highly complicated ways. The background-error covariance matrix is a key component of a data assimilation system, responsible for spreading information from observations to the unobserved locations and state variables. A good estimate of this matrix is essential to produce analyses in which the fields of the state variables are realistic and consistent with each other. Obtaining such an estimate is particularly challenging for tropical locations, where physics-based knowledge does not lead to a straightforward practical formulation.
In a new study, Melinc et al. [2026] propose a novel machine learning-based (ML-based) approach to define a background-error matrix that is equally effective in the midlatitudes and tropics. This approach takes advantage of the power of ML to learn quantitative relationships between different state variables at different locations-relationships that are either not known, or cannot be easily used for the formulation of a background-error matrix based on physics-based knowledge.
Citation: Melinc, B., Perkan, U., & Zaplotnik, Ž. (2026). A unified neural background-error covariance model for midlatitude and tropical atmospheric data assimilation. Journal of Advances in Modeling Earth Systems, 18, e2025MS005360. https://doi.org/10.1029/2025MS005360
Seeking Solutions to PFAS Pollution
Chemical Companies Are Churning Out New PFAS. Where in the World Are They Ending Up?
The Persistence of PFAS
A Peculiar Polymer Paired with Sunlight Could Remove PFAS
Tracing the Path of PFAS Across Antarctica
Pollution Is Rampant. We Might As Well Make Use of It.
Per- and polyfluoroalkyl substances (or PFAS) have been widely used in thousands of common nonstick, waterproof, or stain-resistant products since the 1950s. These “forever c
Per- and polyfluoroalkyl substances (or PFAS) have been widely used in thousands of common nonstick, waterproof, or stain-resistant products since the 1950s. These “forever chemicals” do not break down easily: PFAS make their way into the air, soil, and water, as well as into human and animal bloodstreams and to some of Earth’s most pristine environments. They have been detected even in Antarctica, despite its reputation as a relatively untouched landscape far from the types of products—fast-food wrappers, firefighting foam, nonstick cookware—that contain PFAS.
Research into how PFAS arrive in Antarctica is limited, and most tends to focus on the continent’s coasts, rather than its interior. A new study published in Science Advances aimed to fill some of these gaps by examining PFAS accumulation across a 1,200-kilometer stretch of Antarctica, from the snow pits of Zhongshan Station in East Antarctica to the 4,093-meter peak of Dome A. By examining layers of snow collected from the coast to the interior, researchers sought to better track and understand how PFAS levels vary by location and how these forever chemicals have been able to travel long distances through the upper atmosphere to be deposited in remote regions.
“For substances to get there, they have to be able to transport long distances,” said Ian Cousins, a chemist at Stockholm University and one of the study’s authors. “We know PFAS are very persistent, so that helps. By looking at the patterns of the PFAS contamination in the samples, it gives us clues as to how they’re transported.”
PFAS Arrive by Air and by Sea
Along the 1,200-kilometer route, researchers from the Chinese Academy of Sciences collected 39 snow samples at 30-kilometer intervals, scraping the first few centimeters of snow from the surface to analyze for traces of PFAS.
Zhongshan Station sits near Prydz Bay, and there, researchers collected snow from a 1-meter-deep pit, with samples taken every 5 centimeters. At Dome A, the summit of the East Antarctic Ice Sheet, samples were collected at 10-centimeter intervals from another snow pit; this one was 3 meters deep, providing information about the past several decades of PFAS use.
“It’s quite interesting that we see the historical production record of PFAS in this pit on the top of this mountain in Antarctica,” said Cousins.
PFAS pollution arrives in Antarctica in two ways: via upper atmospheric transport and sea spray. Some PFAS are formed in the atmosphere when volatile precursor chemicals like fluorotelomer alcohols used in textile and paper products break down through reactions with sunlight and oxidants into more stable compounds. The resulting PFAS are later deposited into the snow and ice through precipitation.
Storm winds near the coast create sea spray. “When you have waves, it makes bubbles in the ocean. When the bubbles burst, these sea spray aerosols can be super enriched with PFAS. This has been shown to be a very important transport route,” Cousins said.
To distinguish between sources, researchers measured sodium in the snow to trace the ocean’s salty influence. Sodium levels decreased farther inland, reflecting the fading influence of sea spray toward the interior of the continent. But surprisingly, PFAS concentrations actually increased moving from the coast into the interior.
“That was kind of a bit counterintuitive to me,” explained Cousins, who said he expected PFAS levels to be highest near the coast. “You see the opposite, actually.”
The inland increase is likely explained by higher snowfall totals in the coastal regions, which lead to PFAS concentrations becoming diluted. Inland, where snowfall is lower, even small amounts of PFAS can result in relatively higher concentrations within snow samples.
Additional factors shape PFAS distribution. PFAS levels are higher at the onset of precipitation events when they are rapidly removed from the air. Temperature inversions, too, can trap chemicals. In coastal areas, PFAS are more influenced by sea spray in the winter, whereas stronger sunlight drives the degradation of atmospheric precursors into PFAS in the summer months.
PFAS Presence at Both Poles
This new study also offers implications for the way that PFAS circulate globally. Though industrial activity in the Northern Hemisphere contributes most heavily to PFAS emissions, large-scale atmospheric circulation allows these compounds to reach polar regions. Rapid transport in the upper troposphere may act as an efficient pathway to shuttle PFAS across both hemispheres before they are deposited in the cold, remote regions at both ends of Earth.
“This completes the global picture with agreeing measurements at both poles, solidifying our understanding of the global distribution and drivers of PFAS contamination.”
Even though PFAS levels are higher in the Arctic, both polar regions show similar trends in PFAS concentrations since the 1990s. “It really matches decades of the same records that have been reported from the Arctic,” said Cora Young, an atmospheric chemist at York University, who was not involved in the new study.
“This completes the global picture with agreeing measurements at both poles, solidifying our understanding of the global distribution and drivers of PFAS contamination. The role of CFC [chlorofluorocarbon] replacements, changes in regulation, all of these things are important in the Northern Hemisphere and also the Southern Hemisphere,” said Young.
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Atmospheres
Abrupt temperature swings between consecutive days, referred to as day-to-day temperature variability, have far-reaching impacts on human health, ecosystems, and economic activity. However, how these fluctuations vary from year to year, and what drives them, has remained unclear.
Using observations, reanalysis, and CMIP6 simulations from 1961 to 2014, Liu an
Source: Journal of Geophysical Research: Atmospheres
Abrupt temperature swings between consecutive days, referred to as day-to-day temperature variability, have far-reaching impacts on human health, ecosystems, and economic activity. However, how these fluctuations vary from year to year, and what drives them, has remained unclear.
Using observations, reanalysis, and CMIP6 simulations from 1961 to 2014, Liu and Fu [2026] identify a coherent large-scale pattern of variability across Eurasia and North America. This variability is primarily driven by the north–south movement of warm and cold air masses.
The dominant drivers also vary by season: large-scale meteorological patterns prevail in winter, whereas local land–atmosphere feedbacks become more influential in summer. Together, these processes reshape temperature gradients and modulate storm activity and broader weather systems.
Overall, the findings provide new insights into the mechanisms of temperature variability and offer a scientific basis for improving seasonal climate risk prediction and adaptation strategies.
Citation: Liu, Q., & Fu, C. (2026). Interannual variations in the day-to-day temperature variability in the northern hemisphere and possible causalities. Journal of Geophysical Research: Atmospheres, 131, e2025JD045754. https://doi.org/10.1029/2025JD045754
“I’ve just always felt like art and science are flip sides of the same coin.”
Scientists use tools ranging from models to microscopes to make sense of the world around them. Some might say artists do the same thing using tools such as paintbrushes and musical instruments.
“I’ve just always felt like art and science are flip sides of the same coin, with maybe different outcomes or different processes, but they’re both just getting at the truth of the world,” said Sara Bouchard, a sound art
“I’ve just always felt like art and science are flip sides of the same coin.”
Scientists use tools ranging from models to microscopes to make sense of the world around them. Some might say artists do the same thing using tools such as paintbrushes and musical instruments.
“I’ve just always felt like art and science are flip sides of the same coin, with maybe different outcomes or different processes, but they’re both just getting at the truth of the world,” said Sara Bouchard, a sound artist and composer and adjunct faculty member in the Department of Kinetic Imaging at Virginia Commonwealth University’s (VCU) School of Art.
A recent National Science Foundation–funded collaboration between scientists and artists brought this principle to life.
In fluxART, artists partnered with scientists from FLUXNET, an international network of researchers using eddy covariance techniques to measure how gases move between ecosystems and the atmosphere.
Researchers and artists collaborated on art projects based on data collected at FLUXNET towers. A view from the top of one such tower near Sisters, Ore., is seen here. Credit: Alexander Irving
The scientist-artist pairs worked together in yearlong residencies and produced art pieces—ranging from music compositions and video installations to ceramic works and paintings—that they presented at the Patricia Valian Reser Center for the Creative Arts in Corvalis, Ore., in early 2026.
“Part of the framing of the residency was around flux as this metaphor for connection and belonging and relationships.”
“The metaphor that people use to describe what this science network measures, or does, is that it’s monitoring the breath of the biosphere,” said Maoya Bassiouni, an environmental scientist at the University of California, Berkeley, who directed and developed the residency. “Those fluxes are sort of this giving and receiving between the land and the atmosphere, and it’s exactly what the scientists are doing in the community. So, part of the framing of the residency was around flux as this metaphor for connection and belonging and relationships.”
Bassiouni, who also created artworks in the residency, presented a lecture about the series alongside two other fluxART artists in late May at the National Center for Atmospheric Research’s (NCAR) Mesa Lab in Boulder, Colo.
An installation at NCAR’s Mesa Lab Library featuring all four fluxART projects also opened on 27 May and will be on display through the end of 2026.
En Masse
Bouchard, the sound artist, was paired with Chris Gough, a biogeochemist who serves as the executive director of the Rice Rivers Center at VCU.
Gough studies how factors such as climate and disturbances affect ecosystems, particularly forests and wetlands. Bouchard learned more about Gough’s work by spending a year in his lab.
Virginia Commonwealth University’s Rice Rivers Center Marsh, an AmeriFlux site whose data were used in this project, is located along the James River, seen here. Credit: Megan May Photography
The result was a composition for choir and percussion called En Masse, which explores the connections between communities and ecosystems in a time of climate crisis. The piece’s five movements represent the movement of carbon through the environment: “Air,” “Wood,” “Soil,” “Fire,” and “Breath.”
In addition to vocals and instruments, the composition features birdsong, recordings from a compost pile, sonified data from Gough’s lab, and spoken words gathered from real people sharing their climate anxieties. An excerpt from the “Fire” movement reads,
Future! / Heavy weight on my ribcage / dusty, fragmented Fire! / Clenched jaw, copper taste in my mouth / stark, shifted Fire! / I worry about my kids / desperate, unbreathable Fire! / and their future / squeezed, extreme Future! Fire! Fire! Fire!
Both Bouchard and Gough said they were moved by the piece as it was performed in Corvalis and by seeing the mix of artists and scientists who attended, many traveling from other states.
“I was struck by how engaged both the scientific and artistic communities were,” Gough said. “We walked out, and it was a full room of people. It was energizing, and I think it felt meaningful in a way that stepping up on a conference stage to deliver the traditional convention talk [isn’t].”
September: Orange
In another pairing, video artist Julia Oldham partnered with Christopher Still, a plant ecophysiologist at Oregon State University.
The partnership started with Oldham visiting a 175-foot-tall (53-meter-tall) FLUXNET tower near Sisters, Ore., that Still and his team monitor.
Video artist Julia Oldham visited a FLUXNET tower near Sisters, Ore., with scientist Christopher Still in preparation for creating an art piece based on data gathered at the tower. Credit: Alex Irving
At the top of the tower, a PhenoCam takes photos of the surrounding Deschutes National Forest every half hour. Still uses data from these images to examine how the greenness of the canopy changes over time because such changes can provide information about fluxes in carbon, water, and energy.
“I learned more about what Chris uses the PhenoCam for and got superexcited about the fact that Chris is using color data to understand forests,” Oldham said. “I thought that that was a really beautiful point of overlap for us as a scientist and an artist, to think about color and forests and what we can learn from color as a scientific tool.”
The pair created two pieces. 18//Flux shows how the colors and light from one PhenoCam site changed from 4 a.m. to 9 p.m. throughout the year for 13 years. Each frame is divided into 13 strips, with each strip representing 1 hour of the monitoring period.
The two had conversations throughout the duration of the project about the growing role of wildfires in the area. In fact, one of the FLUXNET towers they were using in the project burned down.
Their conversations led to September: Orange, a three-channel video showing footage from 24 different PhenoCams in the northwestern United States and Canada. When all of the landscapes are the same shade, the video briefly pauses. In September, when wildfires sweep through Cascadia, orange becomes the dominant color. The piece is accompanied by field recordings from Oregon forests and sonified canopy greenness data.
“I think the installation was a wild success, and I had a lot of people tell me how much they enjoyed it and appreciated it,” Still said. “Most people don’t respond to a 2D graph of data…whereas I think almost everyone responds to images, and photographs are really meaningful to people. So I think that is a really brilliant way to draw people into the science.”
Citation: Gardner, E. (2026), Artists and scientists partner to bring atmospheric data to life, Eos, 107, https://doi.org/10.1029/2026EO260178. Published on 3 June 2026.
Source: AGU Advances
The Sun continuously blasts charged, magnetic field–carrying particles, or plasma, in all directions. This solar wind interacts with the magnetic fields and atmospheres of several of our solar system’s planets and other bodies, sculpting long magnetic tails of charged particles—magnetotails—that stretch into space behind them.
Magnetotails contain thin layers of electric current–carrying plasma sheets, which sometimes “flap” in an up-and-down waving motion. Spacecraft
The Sun continuously blasts charged, magnetic field–carrying particles, or plasma, in all directions. This solar wind interacts with the magnetic fields and atmospheres of several of our solar system’s planets and other bodies, sculpting long magnetic tails of charged particles—magnetotails—that stretch into space behind them.
Magnetotails contain thin layers of electric current–carrying plasma sheets, which sometimes “flap” in an up-and-down waving motion. Spacecraft observations have revealed that flapping in Earth’s magnetotail can be driven by a process called magnetic reconnection, in which magnetic field lines rapidly break and then snap together in a new configuration, releasing stored energy. However, whether reconnection plays this same role beyond Earth has thus far been a mystery.
Wen et al. report the first evidence that magnetic reconnection may also trigger magnetotail flapping at Mars.
Unlike Earth, Mars lost its global magnetic field billions of years ago. But it still sports a magnetotail, thanks in large part to interactions between the solar wind and charged particles in its upper atmosphere. Strong magnetic fields embedded in certain patches of the Martian crust—remnants of its lost planet-wide field—also influence the magnetotail.
Until recently, Mars’s magnetotail could only be studied using observations from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. MAVEN showed that the Martian magnetotail is highly dynamic, with a structure that twists, shifts, and flaps—and from which charged particles may escape into space. But because MAVEN can observe only one part of the magnetotail at a time, it couldn’t identify what processes might trigger flapping.
Another spacecraft, China’s Tianwen-1 orbiter, has now provided a second set of eyes. The researchers analyzed simultaneous observations from the two spacecraft, finding that signatures of magnetic reconnection detected by MAVEN in the upstream part of the magnetotail tended to coincide with flapping events detected downstream by Tianwen-1.
Before or during flapping, the spacecraft also detected temporary, twisted plasma structures known as flux ropes. A similar link has previously been observed on Earth, and it suggests that flux ropes generated by magnetic reconnection upstream might propagate downstream, driving instabilities in the magnetotail’s plasma sheets and triggering flapping.
Though more research is needed to confirm these findings, they shed new light on how energy moves and is released in space around Mars—and possibly other planets and celestial objects. (AGU Advances, https://doi.org/10.1029/2026AV002343, 2026)
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Atmospheres
The 2018 Camp Fire was the deadliest and most destructive wildfire in California history. The Camp Fire spread extremely rapidly, driven by strong winds and dry fuels, but also by organized long-range spotting, i.e. lofting and downwind fallout of burning embers to ignite new fires.
Using operational Doppler radar and satellite observations, Lareau [2026] pr
Source: Journal of Geophysical Research: Atmospheres
The 2018 Camp Fire was the deadliest and most destructive wildfire in California history. The Camp Fire spread extremely rapidly, driven by strong winds and dry fuels, but also by organized long-range spotting, i.e. lofting and downwind fallout of burning embers to ignite new fires.
Using operational Doppler radar and satellite observations, Lareau [2026] provides the first high resolution depiction of spotting behavior during an extreme wildfire. Observations show that spot fire events for the Camp Fire occurred 5-10 kilometers ahead of the fire front, quickly merging into new fire lines. Spot fires are not random but aligned within coherent fallout zones that are shaped by plume dynamics and background winds. These results show that operational weather radar can identify lofting and fallout regions in real time, providing a new way to anticipate spotting-driven fire spread and improve early warnings for fast-moving wildfires.
(a) Along wind cross section of Camp Fire plume reflectivity observed by radar measurements, showing distinct updrafts (white arrows) and ashfall regions (blue dashed arrow). Spot fires within 10 minutes of these radar measurements are shown as filled cyan triangles. (b) Map of column maximum radar reflectivity and fire perimeter. In both panels the black dashed line indicates the eastern edge of the town of Paradise, California. Credit: Lareau [2026], Figure 6ab
Citation: Lareau, N. P. (2026). Plume-coupled long-range spotting drove the explosive spread of the 2018 Camp Fire. Journal of Geophysical Research: Atmospheres, 131, e2025JD045798. https://doi.org/10.1029/2025JD045798
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