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Unsupervised anomaly detection for satellite telemetry data using frequent pattern mining and clustering approach (FPMC)

Publication date: Available online 19 November 2025

Source: Advances in Space Research

Author(s): Achraf Djerida

Preliminary application of Chinese high-resolution small SAR satellites in large-scale monitoring of the middle route of the South-to-North Water Diversion Project

Publication date: Available online 19 November 2025

Source: Advances in Space Research

Author(s): Zixuan Ge, Yongkai Wang, Wenhao Wu, Jie Liu, Weijie Ran, Peixian Yuan, Yanan Su, Jiangtao Xu, Jiyuan Hu, Peijie Zhu, Yu Zhang

Earthquake catalog in northeastern Tibetan plateau from the large aperture ChinArray-II through deep learning approach

Geophysical Journal International - Sat, 11/29/2025 - 00:00
AbstractWe present an earthquake catalog in northeastern Tibetan plateau between September 2013 to April 2016 during the ChinArray-II deployment. Using continuous records from 676 transportable ChinArray-II stations and 172 permanent stations, the P/S phases are obtained using one deep learning phase picker. After associating these phases, the events are identified and located to establish the ChinArray-II Regional Earthquake Database (CARED-II). Benefiting from both improved station coverage and sensitive phase picker, CARED-II catalog has 156 057 events (around 3 million picks), about tenfold more than the manual routine catalog (15 967 events) using the permanent stations. The improved event catalog delineates the fault structures clearly. The deep structure of south-dipping north Qilian thrust faults is revealed, consisting with previous geology studies. The hidden faults and fault connectivity are revealed by improved seismicity, especially in the Alxa Block with sparse permanent stations and severe environments restricting geological field work. Moreover, small anthropogenic events are identified and related to highway tunnel construction across Qinling Mountain, forming a straight event cluster. The results demonstrate the high event detection ability of our procedure and reliability of the automatic catalog. Our array-based CARED-II catalog provides improved seismicity images in northeastern Tibet and could be used for further seismology and geotectonic studies.

Spectral induced polarization monitoring of toluene biodegradation by Rhodococcus wratislaviensis in controlled laboratory conditions

Geophysical Journal International - Sat, 11/29/2025 - 00:00
SummaryThe global prevalence of organic pollutants presents a significant environmental challenge, necessitating sustainable remediation strategies. In situ biodegradation emerges as a cost-effective and eco-friendly solution. However, the real-time monitoring of in situ bacterial activities, particularly biodegradation processes, remains a challenge due to the limitations of traditional intrusive methods, including issues of representativeness, reproducibility, and high associated costs. Spectral induced polarization (SIP) has shown sensitivity to surface changes in subsurface environments, especially for biogeochemical reactivity monitoring including those associated with biodegradation. Despite this potential, advances have to be made to quantitatively link SIP parameters to in situ biodegradation processes. This study addresses this gap by conducting controlled biogeophysical experiments on a sand-packed column undergoing biodegradation facilitated by Rhodococcus wratislaviensis IFP 2006. SIP measurements were paired with bacterial growth kinetics to develop a quantitative model estimating bacterial growth. The results demonstrate that SIP, coupled with routine laboratory measurements, can effectively and quantitatively assess bacterial growth and the biodegradation of organic pollutants. These findings highlight the potential of SIP as a non-intrusive and reliable method for monitoring biodegradation in contaminated subsurface environments.

Tailored method for optimizing deflection of the vertical model using multi-directional geoid gradients from SWOT/KaRIn observations

Geophysical Journal International - Sat, 11/29/2025 - 00:00
AbstractThe Surface Water and Ocean Topography mission (SWOT), equipped with the Ka-band Radar Interferometer (KaRIn), provides groundbreaking two-dimensional sea surface heights (SSHs), bringing new potential for optimizing the deflection of the vertical (DOVs). However, conventional DOV modeling—combining along- and cross-track geoid gradients with equal weights—fail to fully exploit the potential of SWOT/KaRIn observations and overlook the spatial variability in precision. We present a tailored method for optimizing DOVs estimation. The method combines geoid gradients in the along-track, cross-track, diagonal (forward and backward) directions with adaptive weighting. The refined weights are employed to exploit the potential of each geoid gradient based on the relationship between the standard deviation of SSHs and the significant wave height. To mitigate data gaps, prior and locally averaged geoid gradients are incorporated in the gaps and overlapping regions. SWOT/KaRIn-derived DOVs and gravity anomalies from the science-phase observations are validated against shipborne gravity in the Philippine Sea. Results indicate that the DOV model derived by the tailored method—particularly by combining triple-directional (along, cross, and diagonally forward) geoid gradients with refined weights—achieves a 7.3% improvement in accuracy over the conventional method. The supplement of additional geoid gradients is critical for mitigating leakage errors caused by missing or reduced observations in the gap regions. Furthermore, the gravity anomaly model recovered from DOVs by stacking 17-cycle observations achieved an accuracy of 2.97 mGal, representing a 7.2% improvement over single-cycle observations. The clear advantages of SWOT/KaRIn observations are gradually emerging in marine gravity recovery.

Caribbean rainfall driven by shifting long-term patterns in the Atlantic high-pressure system, study finds

Phys.org: Earth science - Fri, 11/28/2025 - 19:00
A new study published in Science Advances overturns a long-standing paradigm in climate science that stronger Northern Hemisphere summer insolation produces stronger tropical rainfall. Instead, a precisely dated 129,000-year rainfall reconstruction from a Cuban cave shows that the Caribbean often did the opposite, drying during intervals of intensified summer insolation.

Long-term field data reveal warming cuts temperate forest NO and N₂O emissions by altering soil moisture

Phys.org: Earth science - Fri, 11/28/2025 - 17:38
Researchers from the Institute of Applied Ecology of the Chinese Academy of Sciences and the University of California, Riverside, have investigated how the loss of forest soil gaseous nitrogen (NO, N2O, and N2) is affected by climate warming, highlighting the critical role of these gases in regulating forest nutrient cycling and ecosystem functioning.

The largest ice desert has the fewest ice nuclei worldwide

Phys.org: Earth science - Fri, 11/28/2025 - 16:19
There are fewer ice nuclei in the air above the large ice surfaces of Antarctica than anywhere else in the world. This is the conclusion reached by an international research team led by the Leibniz Institute for Tropospheric Research (TROPOS) based on filter measurements of cloud particles at three locations in Antarctica. These are the first of their kind on the continent. The data fills a knowledge gap and could explain the large proportion of supercooled liquid water in the clouds of the southern polar region.

Channels near 22.235 GHz band improve the accuracy of water vapor profile measurements by microwave sounders

Publication date: Available online 19 November 2025

Source: Advances in Space Research

Author(s): E.V. Pashinov, V.V. Sterlyadkin

Vehicle-Borne GNSS/INS Integration Performance in Urban Environments with KF-GINS, IGNAV, GINav, PSINS and OB-GINS

Publication date: Available online 19 November 2025

Source: Advances in Space Research

Author(s): Wenqian Zhou, Jianhui Cui, Rui Tu, Rufei Liu, Zeyu Li, Xuan Han

Entry trajectory optimization considering blackout zone communication constraint

Publication date: Available online 19 November 2025

Source: Advances in Space Research

Author(s): Rouhe Zhang, Kang Wang, Xinran Duan, Zheng Chen

Investigating wind shear theory associated with Sporadic-E layer formation using WACCM-X and HWM models, ionosondes, and radio occultation

Publication date: Available online 19 November 2025

Source: Advances in Space Research

Author(s): Kimiya Masjed Jamei, A. Mahmoudian

Major droughts linked to ancient Indus Valley Civilization's collapse

Phys.org: Earth science - Thu, 11/27/2025 - 16:00
Successive major droughts, each lasting longer than 85 years, were likely a key factor in the eventual fall of the Indus Valley Civilization, according to a paper published in Communications Earth & Environment. The findings may help explain why this major ancient civilization—a contemporary of ancient Egypt located around the modern India-Pakistan border—slowly declined, and highlights how environmental factors could shape ancient societies.

Satellites spot surprising tsunami patterns: Massive Kamchatka quake challenges old models

Phys.org: Earth science - Thu, 11/27/2025 - 09:28
A satellite deployed to measure ocean surface heights was up to the challenge when a massive earthquake off the Kamchatka Peninsula triggered a Pacific-wide tsunami in late July.

Researchers develop novel bathymetric framework for high-accuracy shallow-water mapping

Phys.org: Earth science - Thu, 11/27/2025 - 01:10
Shallow seas serve as critical transition zones connecting land and the deep ocean, supplying essential resources for navigation, fisheries, energy exploration, and island reef development. Accurate bathymetric data form the foundation for marine engineering, channel safety, resource assessment, and ecological restoration. However, nearly 50% of global shallow-water areas still lack reliable depth information, creating a major barrier to coastal management and sustainable ocean development.

Retrieving Complete Spherical Bouguer and Isostatic Gravity Anomalies Using Global Gravity Forward Models

Geophysical Journal International - Thu, 11/27/2025 - 00:00
SummaryThe estimation of topographic gravity field models has attracted significant interest in recent years due to its growing relevance in Earth sciences. In this study, we present a robust methodology for the computation and comprehensive validation of global, complete spherical Bouguer and isostatic gravity anomalies that are essential for accurately interpreting subsurface mass distributions therefore geological structures. We synthesize these crucial gravitational functionals by leveraging spherical harmonic coefficients from high-resolution global gravity field models and various topographic/topographic-isostatic gravity field models. Our findings underscore the critical role of comprehensive terrain corrections in deriving physically meaningful, complete Bouguer gravity fields. The calculated global anomalies demonstrate strong coherence with established benchmark datasets, such as the World Gravity Map 2012. Residual differences are primarily attributed to variations in input Digital Terrain Models. Comparisons with regional Bouguer datasets reveal systematic biases that are largely explained by differing terrain correction methodologies. After removing this effect, there is a high level of consistency between the calculated global and published regional datasets, highlighting the utility of our global solutions, particularly in regions with sparse terrestrial data. Furthermore, the globally computed isostatic gravity anomalies exhibit significant agreement with both external global and diverse regional datasets, notably without the large systematic biases observed in Bouguer comparisons. This agreement reflects the effectiveness of the combined topographic and isostatic corrections in capturing Earth’s mass balance. This research provides valuable tools for new studies in the geoscience community by offering globally consistent and complete Bouguer and isostatic gravity field anomalies that have been rigorously validated for the ICGEM service.

EPA to Abandon Stricter PM2.5 Air Pollution Limits

EOS - Wed, 11/26/2025 - 19:33
body {background-color: #D2D1D5;} 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.

The U.S. Environmental Protection Agency moved this week to reduce limits on fine particulate air pollution, including soot, set by the Biden administration last year. 

The administration gave up defense of a rule which lowered the standard for air pollution particles measuring less than 2.5 micrometers in diameter, also known as PM2.5. The rule, which would have been fully implemented in 2032, took the standard from 12 micrograms of PM2.5 per cubic meter of air to 9. Such tiny particles, which come from vehicle exhaust, factories, and power plants, are especially harmful to human health because they can infiltrate the lungs and the bloodstream. 

In 2024, EPA estimated the 9-microgram standard could prevent up to 4,500 premature deaths, 2,000 hospital visits, and 800,000 cases of asthma per year. 

“An abundance of scientific evidence shows that going back to the previous standard would fail to provide the level of protection for public health required under the Clean Air Act.”

On 24 November, EPA asked the U.S. Court of Appeals for the D.C. Circuit to strike down the new standard, abandoning its defense against industry trade associations and attorneys general from conservative states that had sued Biden’s EPA over the rule.

In the court filing, EPA took the side of its challengers, stating the rule was created “without the rigorous, stepwise process that Congress required.”

“EPA now confesses error,” the filing said. Though the 9-microgram standard remains in effect currently, the EPA proposed in its filing that the standard revert to the 12-microgram rule finalized in 2020.

Environmental groups said the action undermines the agency’s obligations under the Clean Air Act. “EPA’s motion is a blatant attempt to avoid legal requirements for a rollback, in this case for one of the most impactful actions the agency has taken in recent years to protect public health,” Hayden Hashimoto, an attorney for the Clean Air Task Force, a nonprofit, told AP. “An abundance of scientific evidence shows that going back to the previous standard would fail to provide the level of protection for public health required under the Clean Air Act.”

Particulate air pollution disproportionately affects Black communities and other communities of color, as well as low-income groups. One 2018 study found that people living in poverty were exposed to 35% more PM2.5 than the overall population, and Black people were exposed to 54% higher amounts.

 
Related

In April, a coalition of public health and community groups wrote a letter to EPA Administrator Lee Zeldin asking him to quickly implement the strengthened standard. “There is no legally viable basis for weakening it,” they wrote.

“Our communities already carry the burden of polluted air and higher rates of asthma and heart disease. Weakening soot protections will only deepen these disparities and cost more Black lives,” Yvonka Hall, executive director of the Northeast Ohio Black Health Coalition, one of the groups that signed the letter, said in a statement.

The move to vacate defense of the rule is part of a broader rollback of regulations on industrial facilities by the EPA. Earlier this year, the agency proposed repealing requirements for polluting facilities to report their greenhouse gas emissions. The EPA is expected to propose its own PM2.5 rule early next year.

—Grace van Deelen (@gvd.bsky.social), Staff Writer

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. Text © 2025. 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.

Avalanches are of key importance to glaciers worldwide

Phys.org: Earth science - Wed, 11/26/2025 - 18:00
An international research team has shown that avalanches are crucial to the survival of many glaciers worldwide. The study aims to contribute to better predictions of water resources and natural hazards in the context of global warming.

Researchers find smaller amounts of microplastics in southern Narragansett Bay

Phys.org: Earth science - Wed, 11/26/2025 - 15:32
It's safe to say Rhode Islanders have a symbiotic relationship with Narragansett Bay.

The Land Beneath Antarctica’s Ice Might Be Full of Water

EOS - Wed, 11/26/2025 - 14:28

In Antarctica, beneath the ice, there is liquid water—and potentially a lot of it. That’s the takeaway from new research that used seismographic instruments to probe the still largely unstudied boundary between Antarctica’s bedrock and its ice sheet.

Previous hydrological studies and modeling work have found evidence of lakes and rivers beneath the Antarctic Ice Sheet, though much remains unknown about the region.

Now, using an array of seismic sensors, researchers from Stony Brook University have added more data points to the map of subglacial Antarctica, finding evidence of a layer of water-saturated sediments or rock under the ice. That layer could have implications for models of Antarctic groundwater systems, as well as for future movements of the ice sheet as it slides toward the ocean.

Looking Beneath the Ice with Earthquakes

The data, which will be presented at AGU’s 2025 Annual Meeting, come from an array of more than 600 seismic sensors strung in two long lines totaling about 600 kilometers near the South Pole, put there over the course of two field seasons in Antarctica. The sensors listen for seismic waves that travel through the upper layers of Earth and into the ice sheet.

Those waves carry the signatures of every medium through which they’ve traveled, said Weisen Shen, a geoscientist at Stony Brook University and a paper coauthor. To isolate that information, the researchers applied a mathematical technique called a receiver function to remove the waves’ source information, leaving only the signatures of what they moved through on their journey to the sensor.

In their data from beneath the South Pole, in a region known as the Pensacola-Pole Basin, the researchers found a very low velocity layer, where seismic waves travel too slowly for the conducting medium to be bedrock or ice.

While the authors can’t say exactly what this layer looks like, Shen said the best explanation is a layer of water-saturated sediments or sandstone, likely hundreds of meters thick.

“Anything we can do to try and enhance our knowledge of what’s going on…is just going to help us try and narrow down this really bizarre landscape underneath the ice.”

“We believe…there must be some aquifer system, a groundwater system, that must be preserved beneath the ice,” he said.

The water there could even be connected to groundwater elsewhere in Antarctica, Shen noted. If so, water might be moving around beneath the surface of Antarctica through hydrologically linked basins, and perhaps even out to the ocean.

That scenario could have implications for sea level rise, but, as University of Waterloo glaciologist Christine Dow pointed out, we know far too little to say for sure. In her own modeling, Dow, who wasn’t affiliated with the research, said it appears these basins aren’t connected to the ocean.

“But these are models based on our current knowledge of where’s frozen and where’s not under the Antarctic,” she said. “Perhaps this new information will change that.”

Dow welcomed new data on the mostly uncharted landscape of subglacial Antarctica, where scientists have evidence of lakes, rivers, and groundwater interacting in complex ways, but little hard evidence of the continent’s topography.

“Anything we can do to try and enhance our knowledge of what’s going on…is just going to help us try and narrow down this really bizarre landscape underneath the ice,” she said.

More Questions Than Answers

One question the new data raise is where the heat energy needed to melt the water comes from, noted Hanxiao Wu, a Ph.D. candidate at Stony Brook University and the paper’s first author. It could come from geothermal heat from below, friction caused by the movement of ice at the surface, or some combination of both.

One takeaway from the research is that estimates of geothermal heat flux below Antarctica may need to be bumped upward, Dow said. Models of ice sheet movement and evolution may also need to change to accommodate hundreds of meters of water-saturated sediments. “That’s a game changer,” Dow said.

Should there turn out to be more water beneath Antarctica than previously thought, and should that water move greater distances and in greater amounts, sea levels could rise beyond current predictions, Shen said. It’s too early, however, to estimate any of these probabilities with much certainty, he cautioned.

Right now, Shen and his fellow researchers are focused on improving their dataset and seeking collaborations with other geophysicists to map out the implications of their findings. Wu traveled back to Antarctica for the 2025–2026 field season, where the team is adding another line of seismic sensors to increase coverage and working on tracking the array to better understand changes in snow surface elevation.

In the future, they hope to add additional data from satellites, magnetotelluric surveys, and fiber-optic cables for a more comprehensive look at the ice pack and its underbelly, perhaps as part of the 5th International Polar Year in 2032.

What the scientists will find is unknown. But with millions of square miles of land underneath the ice, the potential for discovery is appropriately vast.

—Nathaniel Scharping (@nathanielscharp), Science Writer

Citation: Scharping, N. (2025), The land beneath Antarctica’s ice might be full of water, Eos, 105, https://doi.org/10.1029/2025EO250435. Published on 26 November 2025. Text © 2025. 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.

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