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Measurement of turbulent velocity and bounds for thermal diffusivity in laser shock compressed foams by x-ray photon correlation spectroscopy

Physical Review E (Plasma physics) - Wed, 10/29/2025 - 10:00

Author(s): Charles Heaton, Hao Yin, Dimitri Khaghani, Hae Ja Lee, Hannah Poole, Eric Blackman, Nina Boiadjieva, Xiaoqian M. Chen, Celine Crépisson, Gilbert W. Collins, Adrien Descamps, Arianna E. Gleason, Christian Gutt, Alexander N. Petsch, Lisa Randolph, Silke Nelson, Peregrine McGehee, Rajan Plumley, Christopher Spindloe, Thomas Stevens, Charlotte Stuart, Joshua J. Turner, Hussein Aluie, Jessica K. Shang, and Gianluca Gregori

Experimental benchmarking of transport coefficients under extreme conditions is required for validation of differing theoretical models. To date, measurement of transport properties of dynamically compressed samples remains a challenge with only a limited number of studies able to quantify transport…


[Phys. Rev. E 112, 045218] Published Wed Oct 29, 2025

ID-GInSAR: An Improved Methodology for Integrating GNSS to Enhance InSAR-Based Deformation Monitoring

Geophysical Journal International - Wed, 10/29/2025 - 00:00
SummaryThis study presents an enhanced method for integrating Global Navigation Satellite System (GNSS) and Interferometric Synthetic Aperture Radar (InSAR), referred to as Iterative Decomposition-based GNSS-enhanced InSAR (ID-GInSAR), to address both spatially correlated components (SCCs) and topographically correlated components (TCCs) in interferogram errors. While traditional GInSAR (GNSS-enhanced InSAR) is effective in mitigating long-wavelength SCCs, it often overlooks TCCs, which are particularly significant in regions with steep topographic gradients. The proposed ID-GInSAR approach employs an iterative decomposition process to decouple and independently model SCCs and TCCs, utilizing a combination of exponential and statistical models. The method is validated using Sentinel-1 SAR and GNSS data from California’s southern Central Valley. Results demonstrate that ID-GInSAR significantly lowers noise in interferograms, enhances the robustness of displacement time series, and improves the accuracy of co-seismic deformation and velocity field estimates. Specifically, ID-GInSAR reduces the root mean square (RMS) between GNSS and InSAR by up to 55% in individual interferograms and by an average of 30.4% in displacement time series compared to traditional GInSAR methods. Furthermore, ID-GInSAR effectively highlights subtle transient deformation, such as coseismic offsets, and provides more robust velocity fields over shorter time spans (less than three years). Finally, we compare our method with other approaches, including Remove/Filter/Restore (RFR) and GACOS, and discuss their applicability scenarios. Collectively, ID-GInSAR provides an alternative integration method for regions with complex topography where ground-based GNSS observations are available.

Rupture Directivity of Moderate to Large Earthquakes in the Slow Deforming Iranian Plateau

Geophysical Journal International - Wed, 10/29/2025 - 00:00
SummaryRupture directivity significantly increases horizontal peak ground acceleration, elongates aftershock clouds, and enlarges meizoseismal areas beyond the fault end in front of the direction of rupture propagation. In this study, we examine the directivity of 25 moderate to large earthquakes (Mw ≥ 6) from 1968 to 2017 in the Iranian plateau by employing relocated earthquake clusters, mapped surface ruptures, focal mechanisms of earthquakes, slip distribution models, spatial distribution of Peak Ground Acceleration (PGA) amplitudes and macroseismic effects. The methodology overcomes the lack of dense seismic networks required to study directivity using methods based on the azimuthal variation of the spectrum of seismic waves. We show that 16 out of the 25 (i.e., 64%) of the earthquakes investigated have mostly unidirectional rupture. This implies that unidirectional ruptures in a slow deforming continental collision zone such as the Iranian Plateau is only slightly less common than those observed globally. With the understanding that unidirectional rupture increases the probability of ground shaking off the termination of the causative faults, our findings highlight the importance of considering the directivity effect in earthquake hazard assessment in Iran and also in other slow deforming continental regions.

The influence of a stably stratified layer on the hydromagnetic waves in the Earth’s core and their electromagnetic torques

Geophysical Journal International - Wed, 10/29/2025 - 00:00
SummaryEvidence from seismic studies, mineral physics, thermal evolution models and geomagnetic observations is inconclusive about the presence of a stably stratified layer at the top of the Earth’s fluid outer core. Such a convectively stable layer could have a strong influence on the internal fluid waves propagating underneath the core-mantle boundary (CMB) that are used to probe the outermost region of the core through the wave interaction with the geomagnetic field and the rotation of the mantle. Here, we numerically investigate the effect of a top stable layer on the outer core fluid waves by calculating the eigenmodes in a neutrally stratified sphere permeated by a magnetic field with and without a top stable layer. We use a numerical model, assuming a flow with an m-fold azimuthal symmetry, that allows for radial motions across the lower boundary of the stable layer and angular momentum exchanges across the CMB through viscous and electromagnetic coupling. On interannual time-scales, we find torsional Alfvén waves that are only marginally affected by weak to moderate stratification strength in the outer layer. At decadal time-scales similarly weak stable layers promote the appearance of waves that propagate primarily within the stable layer itself and resemble Magneto-Archimedes-Coriolis (MAC) waves, even though they interact with the adiabatic fluid core below. These waves can exert viscous and electromagnetic torques on the mantle that are several orders of magnitude larger than those in the neutrally stratified case.

Time-Lapse Airborne EM for monitoring the evolution of a saltwater aquifer - The Bookpurnong case study

Geophysical Journal International - Wed, 10/29/2025 - 00:00
SummaryA novel time-lapse modelling scheme for Airborne Electromagnetics (AEM) monitoring datasets is presented, using data from multiple surveys applied to study the hydro-related evolution of the Bookpurnong floodplain in South Australia. Additionally, it introduces a new wide-ranging approach for this type of study, incorporating new processing, validation, and interpretation tools.Time-Lapse studies are widespread in the literature but are not commonly applied to model EM data, particularly AEM data. This is linked to the challenges of performing overlapping data acquisition with inductive systems. The key features of the new time-lapse scheme, which address these issues, include the definition of independent forward and model meshes, essential for considering discrepancies in the location of soundings which arise in multitemporal AEM data acquisition, and the incorporation of system flight height in the inversion. This proved crucial for achieving satisfactory data fitting and limiting artifact propagation in the time-lapse models.Additionally, a novel processing workflow for AEM multitemporal datasets is presented. This has proven important for effectively processing the multitemporal datasets, which presents new challenges in identifying noise coupling arising from the use of different systems across vintages of data, possible variations in acquisition settings operated by different field crews, and changes in subsurface resistivity in the survey area. Results generated from the time-lapse modelling are evaluated with an Independent Hydrogeological Validation (IHV), designed to support the geophysical models validation and interpretation by providing a first-step hydrogeological evaluation.At Bookpurnong, along a sector of the Murray River floodplain, multitemporal AEM surveys were collected in 2015, 2022 and 2024, to study natural and engineered changes in the groundwater system over time. The time-lapse models show significantly smaller variations compared to those determined with individually modelled survey data sets, while delineating sharply bounded changes in resistivity across the floodplain. This demonstrates the effectiveness of the new time-lapse scheme in minimizing inversion variations typically encountered with independently modelled results affected by larger equivalence issues.Here, AEM models are first compared with resistivity borehole measurements, revealing a strong match between the two methodologies and spatial variations in resistivity consistent with a meandering river across the floodplain. These variations are further validated and interpreted using the IHV approach, which revealed a direct correlation between the hydrological stress of the Murray River and the response of shallow aquifers. Additionally, time-lapse geophysical models, combined with a hydrostratigraphic analysis, allow for a direct correlation between shallow and deep hydrogeological responses.We believe that the time-lapse methodology described here can be widely applied to multitemporal studies using AEM datasets, enabling the study of a broad range of natural processes with great accuracy and at the basin scale.

Judge Stops Shutdown-Related RIFs Indefinitely

EOS - Tue, 10/28/2025 - 21:51
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.

A judge has announced that the government cannot issue further reduction-in-force (RIF) notices to federal employees because of the government shutdown, nor implement RIFs that had already been issued during the shutdown.

The ruling by U.S. District Judge Susan Illston will mark the latest in a months-long court battle over RIFs at federal agencies.

“I think it’s important that we remember that, although we are here talking about statutes and administrative procedure and the like, we are also talking about human lives, and these human lives are being dramatically affected by the activities that we’re discussing this morning,” Judge Illston said at the top of the hearing, which was held at the headquarters of the Northern District of California in San Francisco.

 
Related

The case, American Federation of Government Employees, AFL-CIO v. United States Office of Personnel Management (OPM) (3:25-cv-01780), was first filed in February. AGU joined as a plaintiff in the case in March. Other plaintiffs include Climate Resilient Communities, the Coalition to Protect America’s National Parks, and the American Public Health Association.

Judge Illston granted a temporary restraining order earlier this month, which prevented the government from executing RIFs during the shutdown until further notice.

However, the Trump administration only paused some RIFs, arguing that most of the thousands of layoffs announced since the shutdown are not covered by the court order.

As part of the temporary restraining order, the court ordered the government to provide an accounting of “all RIFs, actual or imminent,” that it planned to execute during the shutdown. The list included 143 Fish and Wildlife Service employees, 355 USGS employees, 272 National Park Service employees, and 474 Bureau of Land Management employees.

On 22 October, Judge Illston broadened the reach of who was protected by the temporary restraining order by adding several unions representing federal employees as plaintiffs.

In today’s hearing, the plaintiffs argued for a preliminary injunction, a move that essentially preserves the status quo before the final judgement of a trial. Danielle Leonard, an attorney representing the plaintiffs, argued that, in this case, the state of affairs prior to the government shutdown should be considered the “status quo.” In essence, this meant seeking for a halt to RIFs that have occurred since the shutdown, not just future RIFs.

The plaintiffs sought prove that the RIFs were “arbitrary or capricious,” a legal standard that is part of the Administrative Procedure Act, which governs how federal agencies operate.

Michael Velchick, an attorney representing the U.S. government, argued that the government’s actions were not only not arbitrary or capricious, but good policy, and “the right thing to do.”

“Morally it’s the right thing to do, and it’s the democratic thing to do,” he said. “The American people selected someone known above all else for his eloquence in communicating to employees that, ‘You’re fired.’”

This was seemingly a reference to the president’s former reality TV show, The Apprentice.

Leonard argued that Velchick’s statement was offensive to the 1.5 million federal employees represented by her clients. She summed up the defendant’s argument like this:

“There is some general authority, and therefore that blesses the specific actions that are happening here for the reasons that the government has given, regardless of how poor those reasons are. And that’s just not the way the law works.”

Judge Illston seemed to agree, stating that the Office of Personnel Management and Office of Management and Budget were prohibited from issuing more RIF notices or implementing those already issued.

The judge noted that she will likely hold an evidentiary hearing to settle a potential dispute over whether specific RIF notices were issued because of the shutdown, or were “already in the works” and unrelated to the shutdown.

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

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
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Six-million-year-old ice discovered in Antarctica offers unprecedented window into a warmer Earth

Phys.org: Earth science - Tue, 10/28/2025 - 20:37
A team of U.S. scientists has discovered the oldest directly dated ice and air on the planet in the Allan Hills region of East Antarctica.

Altitudinal Comparison Between FORMOSAT-7/COSMIC-2 and Digisonde Bottomside Electron Density Profiles Matched at the F2-peak

Publication date: Available online 24 October 2025

Source: Advances in Space Research

Author(s): M. Moses, H. Haralambous, K.S. Paul, S.K. Panda

A high energy cosmic-ray and gamma-ray observatory at the Moon South Pole: the MoonRay concept

Publication date: Available online 24 October 2025

Source: Advances in Space Research

Author(s): P.S. Marrocchesi

Pre-seismic ionospheric disturbances following the 2025 <math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si15.svg" class="math"><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>w</mi></mrow></msub></mrow></math> 7.7 Mandalay, Burma (Myanmar) Earth

Publication date: Available online 24 October 2025

Source: Advances in Space Research

Author(s): Husan Eshkuvatov, Shuanggen Jin, Bobomurat Ahmedov, Shukhrat Mardonov, Shahzod Numonjonov

Effects of Impactor Length-to-Diameter Ratio on the Dynamic Response Resulting from Kinetic Impacts into Monolithic Asteroid Targets

Publication date: Available online 24 October 2025

Source: Advances in Space Research

Author(s): Songyang Wu, Runqiang Chi, Hongyu Zhang, Yongqiang Zhang, Diqi Hu, Wuxiong Cao, Jiaxin Gao, Xianpeng Zhou, Baojun Pang

A Novel Deep Learning Approach for High-Precision Rainfall Intensity Inversion Using Urban Surveillance Audio

Publication date: Available online 23 October 2025

Source: Advances in Space Research

Author(s): Jiangfan Feng, Xi Fu, Shaokang Dong

Automated Annotation and Optimization of Multitask Dataset for Spacecraft

Publication date: Available online 23 October 2025

Source: Advances in Space Research

Author(s): Shengyun Zhao, Linyan Cui, Rui Zhong

Spatial and Temporal Evolution of Wetland Ecological Quality in the Yellow River Delta: A Comprehensive Analysis Based on Multi-Temporal Remote Sensing and Improved Ecological Indices

Publication date: Available online 23 October 2025

Source: Advances in Space Research

Author(s): Ruifeng Liu, Lansong Lv, Yurong Cui, Wenxin Pan, Xiulong Zhang, Juan Fu

Advanced Predictive Modelling of Urban Expansion and Land Surface Temperature Dynamics Using Multi-Scale Machine Learning Approaches

Publication date: Available online 23 October 2025

Source: Advances in Space Research

Author(s): Ahmed Ali Bindajam, Javed Mallick, Hoang Thi Hang, Chander Kumar Singh

Direct simulations of very high energy cosmic ray acceleration in 3D MHD model of a compact star cluster

Publication date: Available online 23 October 2025

Source: Advances in Space Research

Author(s): M.E. Kalyashova, A.M. Bykov, D.V. Badmaev

Corrigendum to “Investigating orbital periodicity in HS 2231+2441 with extended observations”. [Adv. Space Res. 76/2 (2025) 1204–1212]

Publication date: Available online 23 October 2025

Source: Advances in Space Research

Author(s): Huseyin Er, Aykut Ozdonmez, M. Emir Kenger, B. Batuhan Gürbulak, Ilham Nasiroglu

Remote sensing helps confirm Aliso Canyon methane plumes traveled at least 6.2 miles downwind during blowout

Phys.org: Earth science - Tue, 10/28/2025 - 18:44
Using a mix of airborne and satellite images as well as data from ground sensors, a UCLA-led research team has reconstructed how the shape and reach of the methane plumes from the 2015–16 Aliso Canyon gas blowout evolved during the 112-day disaster.

Image: Hurricane Melissa barrels through the Caribbean

Phys.org: Earth science - Tue, 10/28/2025 - 16:30
This image captured by the Copernicus Sentinel-3 mission on 26 October 2025 shows the "brightness temperature" at the top of Hurricane Melissa as it barreled through the Caribbean Sea toward Jamaica, where it is expected to make landfall.

Geoscientist's innovative approach aims to safeguard irrigation canals

Phys.org: Earth science - Tue, 10/28/2025 - 14:04
Irrigation canal maintenance in western Nebraska is taking a giant step forward thanks to an innovative, non-invasive method by Husker geoscientist Mohamed Khalil to check canal integrity. His sophisticated time-lapse analysis pinpoints canal seepage and structural settlement far more accurately and efficiently than traditional approaches—using a technology that can have wide-ranging uses statewide for agriculture, industry and natural resources management.

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