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An international team of researchers, including scientists from Utrecht University and the University of Maryland, has reconstructed the concentration of clumped isotopes of methane in air from the past for the first time. This provides new insights into how atmospheric methane concentrations have changed since the start of the industrial era, around 1850. For the study, the scientists used air that was roughly 40 years old, preserved in compacted snow (firn) in Greenland. The results were published in Science Advances.

Two weeks ago, the Philippine Institute of Volcanology and Seismology recorded three distinct, short-lived explosions in less than five minutes at Taal Volcano. The eruption sent a column of ash and steam up to 1.2 km (0.75 miles) into the air.

A team of international scientists sets sail Thursday from Britain for Greenland to study its rapidly melting ice using drones, mini-submarines and autonomous swimming robots.

A new study led by the University of Barcelona reveals that freshwater exported from the Black Sea to the Aegean Sea triggered major environmental changes across the Eastern Mediterranean.

Paleontologists in China have discovered the oldest chemically verified amber ever found, dating to 385 million years ago. That's approximately 140 million years before dinosaurs roamed Earth. The previous record holder was an amber sample from the Late Carboniferous period, dating to about 320 million years ago.

Heavy precipitation becomes more intense with every degree Earth warms. This affects flooding. Using hourly data from 384 rivers in the Alps, researchers from the WSL Institute for Snow and Avalanche Research SLF modeled how flooding will change by the end of the century. Their projections are significantly bleaker than earlier ones. The findings are published in the journal Science Advances.

As a child going to school in Timika, Indonesia, the nearest major town to Puncak Jaya, Alion Belau could see, on a clear day, that there were glaciers atop the 4,884-meter (16,024-foot) mountain. Some Indigenous peoples, including Belau’s tribe, the Moni, call them “the eternity glaciers” (or, in Indonesian, Salju Abadi).

At 4,884 meters (16,024 feet) tall, Puncak Jaya, in the Indonesian part of the island of New Guinea, is the tallest mountain in Oceania. Credit: Klaus Thymann

Now, as a pilot who flies over Central Papua’s Sudirman mountain range nearly every day, Belau is not seeing as much ice as he used to, even compared to when he first began flying 9 years ago.

“It’s really sad,” he said. “It’s not the eternity iceberg or the eternity glaciers anymore. It’s going to be ‘the 5-year glaciers’ or ‘10-year glaciers.’”

Alion Belau captured this footage as he flew a route over Puncak Jaya in 2016. Over the past 9 years, he’s watched the extent of the mountain’s glaciers shrink. Mapping What Remains

Klaus Thymann, an environmental scientist and explorer, as well as the founder and director of the nonprofit Project Pressure, recently created the first photogrammetry model of the glaciers on Puncak Jaya, aiming to document their current extent and raise awareness about their decline. Photogrammetry uses photography to gain information about the dimensions and location of an environment.

Past research has suggested that in 1850, about 18.8 square kilometers of Puncak Jaya were covered by glaciers. By 2002, that area had shrunk by 88.6%, to 2.14 square kilometers.

According to calculations by the Project Pressure team, the mountain’s East Northwall Firn Glacier had shrunk by 95% since 2002 and is no longer considered a single glacier, but three discrete patches of ice.

A still image from the final 3D photogrammetry model is seen here. In blue is the fragmented East Northwall Firn Glacier, which has decreased in area by approximately 95% since 2002. Model Credit: Klaus Thymann & Pix4D

Thymann has long been interested in documenting “white spots on the map,” or areas with little data. But he’s been particularly interested in equatorial glaciers. In 2024, he and a team of dozens trekked up Uganda’s Rwenzori Mountains to document the decline of glaciers on Mount Stanley.

“We think of palm trees, and furry animals, and warmth, and exotic fruit when we talk about the tropics, not ice,” Thymann said. “The [idea of] tropical glaciers is hugely fascinating.”

They aren’t just fascinating to people from other countries. Belau said one reason the decline of the glaciers is saddening is because their presence used to attract people from across Indonesia to his home province of Papua.

“People, when they go back to Jakarta or other provinces in Indonesia, they will tell their families, ‘Hey, we have ice! We have icebergs. We have glaciers in this country.’ And then they talk about Timika,” he said. “So it’s just something that attracts people to come to visit Timika, and they witness it. But now, not so many people talk about it.”

Ice once covered both of these ridges on Puncak Jaya, but now it is concentrated in the saddle between the two. Credit: Klaus Thymann “Just a Name Now”

Glaciers the world over are shrinking or disappearing altogether in the face of climate change. Since 2000, Earth’s glaciers (excluding the ice sheets of Greenland and Antarctica) have lost an average of 273 billion metric tons of ice per year, according to the European Space Agency. And the loss is accelerating: The amount of ice lost from 2012 to 2023 was 36% higher than the amount lost between 2000 and 2011.

This pair of images, captured by the Thematic Mapper on Landsat 5 in 1988 and by the Operational Land Imager on Landsat 8 in 2017, shows the loss of Puncak Jaya’s glaciers over the course of less than 3 decades. Credit: NASA Earth Observatory images by Joshua Stevens, using Landsat data from the U.S. Geological Survey

As the tallest peak in Oceania, Puncak Jaya is also one of the Seven Summits, or the highest peaks on each continent and a common goal for die-hard mountaineers. The climb up Puncak Jaya is a technical one, but part of what makes it so difficult to summit is the logistics. Thymann obtained a permit and coordinated with local authorities to fly into Timika, where he waited until conditions were safe for a helicopter to take him up the mountain.

“I called it the cloud lottery,” he said.

Even on the mountain, there were more cloud lotteries while Thymann waited for enough visibility. On its face, the work, done over the course of several days, was simple.

Thymann worked with a local military guard who had accompanied him to place colorful ground control targets around the area. These targets helped Thymann’s drone to calibrate its location as it captured hundreds of high-resolution images. These images were later combined to create the photogrammetry model.

Klaus Thymann used a drone to capture hundreds of photos of Puncak Jaya and what’s left of its glaciers. These images were combined to create a photogrammetry model. Credit: Klaus Thymann

“I was surprised to see there was still some ice left,” Thymann said. “But mountains are like fractals. It’s very difficult to judge scale. And, of course, it’s very very little that’s left.”

Francine Hematang, a forestry and environmental scientist at Papua University in Indonesia, was not involved with Project Pressure’s efforts but recently led a study that used satellite data to document the decline of Puncak Jaya’s glaciers from 1980 to 2024. The study’s results suggested that the glacier area atop the mountain declined by 97% in that 44-year period. Four of the mountain’s six glaciers disappeared completely. Hematang called Project Pressure’s survey “excellent.”

“It uses photogrammetry, which will certainly capture the details of the glacier much better than satellite imagery,” he told Eos in an email. “With photogrammetry, we might be able to see the glacier’s boundaries and slope gradients in detail, and perhaps estimate its volume as well.”

Belau said that the accurate mapping data could allow locals to share the stories of the glaciers with future generations. After all, he said, “eternity glaciers…is just a name now.”

Indigenous peoples living near Puncak Jaya, including the Moni, call the glaciers atop Puncak Jaya the “eternity glaciers.” “It’s just a name now,” said Alion Belau, a Moni pilot. Credit: Klaus Thymann

—Emily Gardner (@emfurd.bsky.social), Associate Editor

Citation: Gardner, E. (2026), The “eternity glaciers” are almost gone, Eos, 107, https://doi.org/10.1029/2026EO260228. Published on 16 July 2026. Text © 2026. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Author(s): G. Pérez-Callejo, E. Stambulchik, R. Florido, and M. A. Gigosos

There is an ongoing interest in using spectroscopy in inertial confinement fusion (ICF) experiments, where dopants such as krypton can provide vital information about the temperature and density of the imploding plasma. While the most advanced tools for calculating Stark profiles are computer simula…

[Phys. Rev. E 114, 015212] Published Thu Jul 16, 2026

SummarySufficiently accurate 3-D seismic wave modelling in the presence of topography remains computationally demanding, particularly when curvilinear discretizations are applied throughout the full domain. We develop an overset Virieux-Lebedev finite-difference framework that confines the curvilinear Lebedev-grid (LG) discretization to a near-surface patch and couples it to a standard staggered-grid (SSG) scheme in the deeper region through wavefield exchange across an overlap zone. The approach aims to reproduce traction-free free-surface effects and topographic scattering while reducing the cost associated with domain-wide curvilinear LG finite-difference operators. We first verify the underlying mimetic finite-difference implementation using homogeneous half-space benchmarks with both flat and Gaussian topographic free surfaces by comparison with reference solutions. We then assess the overset coupling using a series of verification tests, including a homogeneous Cartesian benchmark,a layered model with topography and impedance-contrast interfaces, and a modified GO_3D_OBS crustal model. Across these experiments, the receiver seismograms and wavefield snapshots exhibit no discernible artefacts attributable to the overset coupling interface, and the time-frequency envelope and phase misfit measures indicate close waveform agreement. Runtime profiling further indicates substantial efficiency gains when the LG overset thickness is held fixed, and a representative GO_3D_OBS experiment achieves a marked reduction in wall-clock time relative to a full-domain LG simulation. These results demonstrate that the proposed overset strategy enables efficient and sufficiently accurate 3-D wave propagation modelling for complex topographic settings relevant to waveform-based imaging and inversion.

SummaryKnowing and monitoring the spatial distribution of ambient seismic noise sources is essential for correlation-based investigations in seismology. The omnipresent primary and secondary microseismic noise characterizes the ocean-generated noise of the seismic spectrum and has been studied through observations and modeling to better constrain the source mechanisms, the source regions, and their temporal variability. In this study, we demonstrate the potential of a single six-degree-of-freedom (6-DoF) station, observing co-located translational and rotational ground motions, to determine and continuously monitor the source directions of the secondary microseismic wavefield. We harness direct rotational ground motion data obtained with the ROMY ring laser array. The effective array-like capability of a single 6-DoF station to separate Love and Rayleigh waves, both constituents of the secondary microseismic wavefield, by their polarization enables the independent estimation of the dominant source directions and the monitoring of their seasonal evolution. An anticipated seasonality is evident, with a dominant source direction for Love (254○) and Rayleigh (277○) waves in winter, whereas in summer no clear dominant direction emerges due to an absence of strong nearby sources. We compare 6-DoF-based backazimuth estimates with those of seismic array beamforming and find close agreement concerning the dominant source directions, particularly in the case of migrating pelagic storms in the North Atlantic associated with strong ocean wave activity over several days. In winter, a systematic bias of about 25○ to 35○ for Rayleigh waves and 50○ for Love waves is identified between the 6-DoF-based backazimuth estimates and those inferred for significant wave heights obtained from satellite altimetry and model-based seismic noise source maps. Our results provide a proof-of-concept for the direction monitoring of the secondary microseismic noise for both Love and Rayleigh waves using direct rotational observations, thereby reducing reliance on array-derived estimates. The advent of portable high-sensitive rotation sensors will facilitate constraining spatial seismic noise source distributions and temporal variations therein with future 6-DoF station networks potentially replacing or complementing traditional seismic array deployments.

SummaryElastic full waveform inversion (EFWI) provides high-resolution subsurface P- and S-wave velocity models essential for formation lithology and fluid characterization. However, its strong nonlinearity makes it highly susceptible to the local-minima entrapment when low-frequency seismic data or an accurate initial model is unavailable. Furthermore, the coupled sensitivity of multi-component seismic data to distinct elastic parameters introduces a multi-parameter crosstalk effect that further degrades inversion accuracy. Although well-log data contain rich, inherently decoupled prior information of subsurface elastic parameters, a fundamental dimensional mismatch between 1D well logs and the 2D/3D inversion domain prevents their direct integration into conventional EFWI. To overcome these limitations, a joint physical-model- and multi-source-data-driven (JPM-MSDD) EFWI framework is proposed. The correlation between common mid-point (CMP) gathers and 1D vertical velocity profiles is exploited to resolve the dimensional mismatch, enabling well-log data to directly serve as training labels. A neural network is trained to map consecutive adjacent CMP gathers of multi-component seismic data to 1D P- and S-wave velocity profiles under a semi-supervised learning scheme, in which well-side CMP–log pairs form the labeled dataset while model-driven EFWI furnishes physics-consistent pseudo-labels for unlabeled gathers. In this way, the proposed method is able to reduce the reliance on large labeled datasets and enhance the physical interpretation of inversion results. To further reduce the nonlinearity of EFWI, the spatially related information of seismic data is incorporated through position embedding on seismic traces. By integrating multi-source data, including well-log data, multi-component seismic data, and spatial information of seismic traces, into EFWI process, even in the absence of low-frequency components of seismic data, a very good low-wavenumber model can be inverted for conventional model-driven EFWI to prevent the inversion from falling into local minima. Additionally, the proposed method can mitigate the crosstalk of multi-parameters to a certain extent. The synthetic and field data examples demonstrate that the proposed joint physical-model- and multi-source-data-driven EFWI can invert vp and vs models effectively.

Methane is one of the most abundant greenhouse gases on Earth, and, when compared with carbon dioxide, it is 28 times more potent at trapping heat in the atmosphere.

As the climate warms, it’s increasingly urgent to understand where methane comes from. Researchers can analyze the ratios of different carbon isotopes within methane to learn whether that sample came from fossil fuels or from other sources, such as wetlands or agriculture.

“I think this could end up being a landmark study.”

Sometimes, though, even these isotopic fingerprints leave room for uncertainty. New research examined several hundred liters of air gathered from compacted snow in Greenland in an even more precise way. The study, which marks the first time researchers have reconstructed the clumped isotopologue signature of atmospheric methane from past air, was published today in Science Advances.

“I think this could end up being a landmark study,” Edwin Schauble, a geochemist at the University of California, Los Angeles, who was not involved in the research, told Eos via email. “Methane is such an important greenhouse gas and tracer of the carbon cycle that the prospect of getting a better understanding of its history and future is exciting.”

The Nitty-Gritty

Methane (CH4) is made up of one carbon and four hydrogen molecules.

Isotopes, of course, refer to atoms of the same chemical element that have different numbers of neutrons. For instance, carbon naturally occurs in three isotopes: carbon-12, carbon-13, and carbon-14, with carbon-12 being the most common. Hydrogen has three naturally occurring isotopes, including deuterium (which has one proton and one neutron).

The word “isotopes,” explained Jiayang Sun, a geochemist who was a Ph.D. student at the University of Maryland when he coauthored the new paper, refers to elements at the atomic level.

“But when we say ‘isotopologue,’ it’s a word on the molecular level,” he said. “For clumped isotopologues, it’s two or more rare isotopes substituted into one molecule.”

This could mean that the carbon-12 in a methane molecule is replaced with a carbon-13 and one of the molecule’s hydrogens is replaced with deuterium, or it could mean that two of the hydrogens in the same molecule are replaced with two deuteriums.

“In some cases, the information from clumped isotopologues gives you information that’s independent from that provided by the straight isotopes,” said James Farquhar, a geochemist at the University of Maryland. “It gives us a little bit of a better understanding, or better constraints.”

Higher anthropogenic emissions result in lower clumped methane concentrations. However, clumped methane molecules take many years to reach equilibrium, so an increase in methane emissions might not show up in the clumped isotope signal for decades.

New Insights from Old Air

Modeling reflects that emissions of methane have changed over the course of the industrial era. NOAA data show that atmospheric methane levels have risen since the 1980s, with a plateau from 1999 to 2006. The new study’s researchers wanted to take a closer look at these changes by examining the clumped isotopes in air samples from the past.

“The overall trend is kind of clear, but when it comes to detailed allocation of total emissions to each source…the uncertainties related to that are still high,” Sun said.

Because methane makes up only about 2 parts per million of air, and clumped isotopes only represent part of that, the team would need a lot of air to undertake this investigation.

A team of researchers gathers a firn sample. Credit: Thomas Röckmann

But where do you get several hundred liters of decades-old air? One method is to use air found in firn, compacted snow that is the intermediate stage between snow and glacial ice. Researchers from Utrecht University, including atmospheric scientists Malavika Sivan and Thomas Röckmann, happened to have several hundred liters on hand.

The samples were gathered in 2018 as part of the East Greenland Ice-Core Project (EastGRIP). A team of researchers, including Röckmann, drilled a hole into the ice and inserted a 5-meter-long bladder and a set of three tubes. The bladder was inflated to seal the hole and prevent contamination. The tubes then pulled 30-year-old air out from the pores within the firn and pumped it into containers on the surface.

The Utrecht team was interested in examining the clumped isotope levels, but they didn’t have a mass spectrometer that could conduct such analysis on their relatively limited sample size. This made the University of Maryland researchers, who had the spectrometer but not the samples, a perfect partner.

After measuring the samples, the team used modeling to conclude that clumped methane reached a low in approximately 1993.

“Our model suggests that was caused by the increased anthropogenic methane emissions during the industrial period (the 1800s),” Sivan wrote in an email to Eos. “Clumped methane molecules take a very long time to equilibrate after such perturbations, hence the lag in the signal.”

Future Methane Levels

By helping us understand more about our past, this work could be combined with traditional bulk isotope measurements to improve modeling of future atmospheric methane levels.

“Not only do their results tell us much more about methane’s past history, their findings may also be very helpful in targeting pathways to bring methane’s rise under control.”

“It provides the data that would be needed to understand how we got here in terms of the isotopic compositions, and that’s a constraint that will be of value if we’re going to make interpretations about changes that happen in the future,” Farquhar said.

Euan Nisbet, an Earth scientist and professor emeritus at Royal Holloway University of London, said that clumped isotope research is “very much the forefront” of improving understanding of the global methane budget, and that this new work is “a very fine study.”

“Not only do their results tell us much more about methane’s past history, their findings may also be very helpful in targeting pathways to bring methane’s rise under control,” he said.

—Emily Gardner (@emfurd.bsky.social), Associate Editor

Citation: Gardner, E. (2026), These “clumped” molecules could offer clues about Earth’s climate, Eos, 107, https://doi.org/10.1029/2026EO260235. Published on 15 July 2026. Text © 2026. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

While particulate matter air pollution from human activity in transportation, households and industry is decreasing in Europe, thanks to strict regulations, another source is developing in the opposite direction: desert dust.

Wetlands have shaped human life in Europe since ancient times. These ecosystems provided essential resources and safe havens for plants and animals, and in many regions they also held spiritual and ritual significance. For millennia, wetlands covered vast parts of the European continent.

New Antarctic research shows the deepest layer of the Southern Ocean is shrinking faster than scientists realized, with the rate of change accelerating over the past decade. This is of worldwide significance because as it sinks and fills up to 40% of the global ocean volume, the cold, dense water known as Antarctic Bottom Water (AABW) drives Earth's system of currents and regulates our climate.

Australia's ocean territory is vast and covers an area more than 1.5 times the nation's landmass. Within these waters is a diversity of resources, marine species and habitats. And they're deep. Excluding Antarctic waters, 70% of Australia's ocean territory is deeper than 1,000 meters (3,281 feet), and nearly 50% is deeper than 3,000 meters (9,843 feet).

When Hanna Rae Martens visits the solar park she studies in northern Germany, she finds meadow pipits perched on the panels. They launch off to catch insects, then return, using the panels like tree branches.

This solar park, built on rewetted peatland, hosts a more diverse bird community than adjacent drained farmland, according to a new study in Ecological Solutions and Evidence. The findings suggest that combining peatland restoration with solar energy development could benefit birds.

Healthy peatlands hold large quantities of organic matter and, as a result, store more carbon than any other terrestrial ecosystem type.

In drained peatlands, on the other hand, that stored carbon is released to the atmosphere, presenting a major climate problem. In Germany, 95% of peatlands are degraded, and they account for 37% of all annual agricultural greenhouse gas emissions. Globally, drained peatlands emit 5% of all anthropogenic greenhouse gases. That is roughly twice what air travel produces.

Installing solar panels on rewetted peatland is one proposed [solution]: The land gets restored while landowners earn income from energy production.

Rewetting peatlands reduces emissions, but it also makes most crops impossible to grow, reducing the land’s economic prospects. Installing solar panels on rewetted peatland is one proposed way to resolve that: The land gets restored while landowners earn income from energy production.

Martens, a peatland ecologist at the University of Greifswald, led what she says is one of the first studies to examine what that setup means for birds. She and her colleagues tracked bird species at the solar park and at nearby drained grassland throughout the 2024 breeding season.

An Unusual Flock

The team used six low-cost AudioMoth recorders at the solar park and six at the drained grassland site. From March through October 2024, each recorder captured 40-second audio clips of the landscape every 4 minutes. The team generated a large dataset that was then run through BirdNet, an open-source neural network trained to identify bird species from their calls. To reduce false positives, the researchers applied species-specific confidence thresholds before counting any detection.

The solar park attracted a mix of species, including some typically found in wetlands, wooded edges, and urban areas. “The presence of wetland species like reed bunting and the endangered meadow pipit shows that the solar park is truly rewetted,” Martens said. “But we also recorded species like Eurasian tree sparrow and tree pipit, which are not typically found in peatlands. They all appear to use the structure of the solar panels.”

A solar park built on rewetted peatland hosts a more diverse bird community than adjacent drained farmland, new research suggests. Credit: Wattmanufactur, CC BY

Though the overall number of species was similar across both sites, the solar park scored significantly higher on two standard diversity indices—the Shannon and Simpson indices. In other words, it hosted a more even and consistently present community of common species.

Promising, with Caveats

Outside scientists said the results were worth attention but cautioned against reading too much into them.

“I think this is a great idea to study,” said Michael Schummer, an associate professor of wetland wildlife at the SUNY College of Environmental Science and Forestry who was not involved in the research. But he pointed to a methodological concern: The audio recorders inside the solar park were spaced as close as 90 meters apart, below the 250-meter minimum standard for bird monitoring surveys. At that distance, multiple recording stations may capture sounds from the same bird territory, potentially inflating diversity estimates.

“Just as we want more biodiversity in the world, I think we need more diversity in our landscapes.”

Guido Bakema, a soil scientist at Wageningen University who was also not part of the study, raised a separate issue. The study, he said, compared the rewetted solar park to drained grassland but not to a rewetted peatland without solar panels, raising the question of whether it was the rewetting or the solar panels that accounted for the change in bird diversity. “It would be better if they had separated this,” he said.

The authors acknowledged these limitations directly, agreeing that a lack of replicates in this study means that the effects of rewetting and the addition of solar panels cannot be isolated. However, at the time of the study, no other operational rewetted peatland solar park existed nearby for comparison.

Martens is already working to address those gaps. She has expanded her research to five sites this year and plans to examine how design choices such as panel height, spacing, and row width affect which species show up.

“Just as we want more biodiversity in the world, I think we need more diversity in our landscapes,” she said.

—Larissa G. Capella (@CapellaLarissa), Science Writer

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Citation: Capella, L. G. (2026), For the birds: Solar panels over peatlands may increase avian biodiversity, Eos, 107, https://doi.org/10.1029/2026EO260229. Published on 15 July 2026. Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

In the aftermath of the devastating July 4, 2025, floods that took 139 lives in Central Texas, an associate professor at The University of Texas at Austin set out to make a new type of outdoor flood alarm: a low-tech, loud alarm that anyone could "set and forget"—just like a smoke detector.

Author(s): Benjamin Wang, Henry Fetsch, and Nathaniel J. Fisch

The fast ignition paradigm previously developed for inertial confinement fusion is here extended to magnetized linear inertial fusion. The authors’ model showcases fast ignition’s potential to lead to more practical, cost-effective, and engineering-wise viable magnetized linear inertial fusion designs.

#AdvancingField #ClearMotivation

[Phys. Rev. E 114, 015211] Published Wed Jul 15, 2026

SummaryHigh-frequency (> 1Hz) coda waves consist of multiply scattered seismic energy that follows direct body wave arrivals and exhibit high sensitivity to small-scale lithospheric heterogeneities and attenuation. The decay and shape of coda wave envelopes are mainly influenced by intrinsic attenuation, associated with irreversible energy loss due to anelastic processes, and scattering attenuation, resulting from wave redirection caused by heterogeneity. However, these two effects are strongly coupled in observations, making their separation challenging. Here, we apply a Conditional Variational Auto-Encoder (CVAE) to 28,393 high-frequency, vertical-component coda wave envelopes recorded across the eastern margin of the Tibetan Plateau. By conditioning the model on epicentral distance, the trained CVAE extracts two latent variables that characterize the dominant envelope-shape variations independent of the first-order distance effect. The first latent variable mainly modulates P/S amplitude ratio and post-peak decay behavior, showing trends qualitatively consistent with intrinsic attenuation effects. Its spatial distribution reveals lower values within the stable Sichuan Basin and high values across the tectonically active Tibetan Plateau side, consistent with previous attenuation studies. The second latent variable primarily controls envelope broadening and peak delay, consistent with scattering-related energy redistribution. Its spatial pattern suggests enhanced scattering-related broadening in the region affected by loose sedimentary cover in the basin and fault-related fracturing in the plateau. The synthetic data test further supports the qualitative interpretation of the latent variables, while also showing cross-sensitivities between them. These results indicate that the CVAE can extract attenuation-related envelope-shape features, rather than directly decoupling intrinsic and scattering attenuation parameters. Our findings demonstrate the potential of CVAE-based approaches for extracting physically interpretable attenuation-related patterns from large coda envelope datasets in tectonically complex regions.