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SummaryAccurate three-dimensional (3D) density models aid dynamics and oil exploration, yet inversion in complex regions faces non-uniqueness and noise. Due to the non-uniqueness and noise sensitivity of the solution process, accurately resolving spatial density variations from gravity data remains a major challenge. Wavelet decomposition is applied to the separation of gravity signals, and inverting the processed signals can effectively reduce non-uniqueness. However, wavelet multiscale decomposition can suffer from inter-layer crosstalk and boundary blurring due to incomplete signal separation. To address this, we proposed the Layered-Integrated Density Inversion Method (LID). The process begins with a layered inversion using wavelet decomposition. This integrated model serves as the initial model in the subsequent simulated annealing inversion. Simulation experiments showed that the Root Mean Square Error (RMSE) of the LID results is 0.056 g/cm3, representing a 63.47% improvement over the traditional method, which is based on wavelet layered inversion. In noise resistance experiments, the RMSE of the LID results was 0.077 g/cm3, a 54.67% improvement over the traditional method. Applying the method to the South China Sea (SCS) using Surface Water and Ocean Topography (SWOT) satellite vertical gravity gradient data, we identified three prominent geological features: (1) traces of seafloor spreading along the mid-ocean ridge of the SCS; (2) fractures generated during subduction of SCS plate; (3) anomalous signals detected southeast of Palawan, which possibly correspond to remnants of the Paleo-Pacific plate. These findings align with existing theoretical models, providing independent evidence for rift dynamics and post-spreading crustal evolution of this passive continental margin.

When most people hear the phrase "ocean acidification," they think of coral reefs, shellfish or declining fisheries. Those concerns are real. But while working on our recent research, I found myself asking a different question: What if ocean acidification is telling us something much bigger than the health of marine ecosystems?

Ocean tides push upstream along coastal rivers, in some cases reaching hundreds of kilometers (hundreds of miles) inland. These inland stretches are known as tidal rivers, and they're the scene of complex interactions between the river current and tidal oscillations. When rivers flood, tidal dynamics can sometimes add to a river's height, increasing overall peak water levels and amplifying flooding.

Methane (CH4) is a potent greenhouse gas whose concentration in the atmosphere has risen sharply in recent decades. Wetlands are the largest natural source of methane to the atmosphere, but large uncertainties remain about how much methane comes from wetlands and how these emissions may increase in response to a changing climate. Tropical wetlands, including those in the Amazon, produce substantial amounts of methane, but accurately estimating their emission sources and magnitudes remains difficult. One reason is the lack of measurement data, especially in the tropics, where extensive cloud cover interferes with satellite observations and ground-based measurements are sparse.

In the heart of the Congo Basin's Cuvette Centrale, a large depression that hosts the world's largest tropical wetland complex, lie two vast, shallow blackwater lakes, Lake Tumba and Lake Mai Ndombe. Together, they are roughly the size of 420,000 football fields.

Many parts of Western Europe are currently wilting under a heat wave. These blistering spells can last for a week or more, and although they are common in most summers, it is difficult to predict how long they will last.

Source: AGU Advances

Ocean tides push upstream along coastal rivers, in some cases reaching hundreds of kilometers inland. These inland stretches are known as tidal rivers, and they’re the scene of complex interactions between the river current and tidal oscillations. When rivers flood, tidal dynamics can sometimes add to a river’s height, increasing overall peak water levels and amplifying flooding.

This heightening mechanism occurred in China’s Yangtze River, where disastrous floods in both 1954 and 2020 were aided by tides. To learn more, Guo et al. combined data on river discharge and tides from both flood periods, along with a tidal model, to explore how interactions between the river and incoming tides conspired to create anomalously high water levels.

The authors found that peak water levels in both floods occurred around 1 to 2 weeks after peak river discharge during perigean spring tides when both the Sun and Moon are in optimal positions to create high tides. They hypothesize that peak river discharge rates suppress subharmonic tidal amplitudes, while intermediate rates of discharge allow for greater amplitudes and therefore higher water levels. Additionally, river water takes some time to fully move downstream, meaning that water levels are higher in the days following floods, adding to the effects of tidal inflows.

Comparing the two floods, the authors noted that channel deepening caused by sediment depletion from the Three Gorges Dam helped create higher water levels in 2020 than in 1954. Additionally, higher sea levels in 2020 helped water move upstream, also contributing to peak water levels.

Looking to other tidal rivers around the world, the authors say that cumulatively, more than 3,380 kilometers of tidal rivers are potentially exposed to floods caused by similar mechanisms. Other rivers, such as the Mekong and the Amazon, also see similar tidal subharmonics, meaning the same forces could conspire to create extra-large floods as swollen rivers and incoming ocean water combine. (AGU Advances, https://doi.org/10.1029/2025AV002247, 2026)

—Nathaniel Scharping (@nathanielscharp), Science Writer

Citation: Scharping, N. (2026), How tides and river water combine to amplify floods, Eos, 107, https://doi.org/10.1029/2026EO260230. Published on 14 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.

A Florida State University paleoclimatologist led the creation of a global database hosting thousands of seawater isotope measurements collected over almost 50 years that will aid scientists in generating more accurate climate reconstructions and predictions.

Contrary to conventional geological thinking, the Hawaiian mantle plume has gotten hotter by about 250°C (480°F) over the past 47 million years. This discovery, led by Earth scientists at the University of Hawai'i at Mānoa, reverses the long-held idea that hotspots start out very hot and progressively cool over time. The study, published recently in Earth and Planetary Science Letters, also found that heat surges produced the two largest volcanoes along the Northwestern and Main Hawaiian Island chain.

After a typhoon surprised a research cruise, scientists took advantage of the unique sampling opportunity to reveal rapid changes in bacterioplankton communities and biogeochemical cycling.

SummarySeismic moment tensors provide simple representations of a wide range of event types, including earthquakes, volcanic events, landslides, and explosions. Estimating the six parameters of a seismic moment tensor is subject to inaccuracies in the assumed Earth model, whether it is characterized by a simple layered structure (1D) or by heterogeneities (3D). Using recorded data and seismic wavefield simulations in 3D Earth models, we estimate double-couple and full moment tensors using MTUQ software, and then we quantify the differences among moment tensors due to the different Earth models. We establish new capabilities for implementing 3D Earth models from the EarthScope Earth Model Collaboration (EMC) into the wave propagation code SPECFEM3D Globe. The three workflow components—EMC, SPECFEM3D Globe, and MTUQ—are publicly available, thereby maximizing possibilities for access, reproducibility, and future enhancements. We demonstrate the source estimation workflow in the region of Alaska, using 5earthquakes and 53D Earth models. Using misfit measures from the moment tensor estimation, we can quantify the performance of both the moment tensor and also the underlying Earth model. For this limited data set of 5 well-recorded events, we demonstrate how to examine basic questions of source variability, tomographic model evaluation, and the reliability of non-double-couple components of moment tensors. The procedures enable quantification and visualization of moment tensor uncertainties due to Earth models, while also offering direct comparison of tomographic models with an independent reference set of data.

SummarySeismic anisotropy observations can constrain flow and deformation in the lowermost mantle (D″). D″ deformation is often attributed either to changes of mantle flow from mostly horizontal to upwelling near deep mantle plumes or edges of the two antipodal large low-velocity provinces (LLVPs), or to strong deformation in slab-dominated deep mantle regions. A unified understanding of deep mantle flow and its drivers, however, is still developing. We investigate D″ anisotropy beneath Australia using a novel approach combining array processing and shear-wave splitting measurements applied to core-traversing seismic waves which reflect off the underside of the core-mantle boundary up to two times (called SKS, S2KS, and S3KS). Strong differences in splitting between pairs of phases that sample the upper mantle in a similar way but sample different portions of the D″ layer (e.g., SKS-SKKS or SKS-S3KS) can be interpreted as due to a contribution from lowermost mantle anisotropy to the splitting of one or both phases. Using this approach, we detect strong anisotropy in two locations at the southwestern edge of the Pacific LLVP, which we attribute to a change from mostly horizontal to upwelling flow. One of these locations coincides with a previously suggested mantle plume that has not yet reached the surface. We also identify anisotropy south of Australia, where seismic velocities are faster than average and slab remnants may be present. Beneath much of the Australian continent itself, we see little or no evidence for splitting discrepancies, which may be evidence for isotropic, or only weakly anisotropic, lowermost mantle. Our study region thus uniquely showcases seismic anisotropy in diverse deep mantle environments, associated with a possible deep mantle plume, the edge of the Pacific LLVP, and potential remnant slab material.

Japan is well known for its large earthquakes, but not all regions show the same patterns of earthquake activity. One way to understand which places tend to experience large or small earthquakes is the b-value, a key statistical measure long used by researchers to understand seismicity and assess earthquake occurrence patterns.

The lava that buried entire neighborhoods during the 2018 Kīlauea eruption was composed of nearly 80% gas bubbles near its source. A recent study shows that those bubbles played a central role in controlling how fast and far the lava traveled and that lava flow models need to account for bubbles to more accurately forecast where lava will stop.

Earth scientists at Nanyang Technological University, Singapore (NTU Singapore) have published an international study showing that major earthquakes in Southeast Asia can affect regional relative sea-level projections.

Earth has a natural thermostat that has kept the planet habitable for more than 100 million years. Scientists have struggled to fully explain how it works, but new research identifies a missing link between phosphate availability and sea level. Temperature influenced the size of polar ice sheets and sea level. Sea level changes drove the availability of this nutrient and controlled how much carbon was buried in the ocean, which in turn regulated how much carbon dioxide stayed in the atmosphere and how warm or cool the planet ran.

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In the United States and elsewhere, ocean research infrastructure is facing a funding crisis. The U.S. National Science Foundation recently proposed dismantling hundreds of deep-ocean observation instruments, though it reversed the decision after public outcry. Still, a lagging NOAA budget and cuts to federal research funding have slowed the deployment of U.S.-owned instruments that measure ocean metrics and left the future of Argo, a global fleet of robotic instruments drifting in the ocean, in question. In addition, the number of observational floats deployed by Europe, as well as the number of active European floats, has dropped steadily since about 2020.

A study published in Nature Climate Change quantifies the impact that changes in funding could have on ocean data. Through a series of experiments, the research team showed that even small changes to the availability of data within the Global Ocean Observing System (GOOS), a United Nations–supported network of ocean observations, would significantly decrease the quality of ocean heat information available to researchers, making global climate and weather predictions more difficult.

Without U.S. contributions to the network, for example, “we lose the capability to monitor ocean warming,” said Lijing Cheng, an oceanographer at the Chinese Academy of Sciences and coauthor of the new study. Cheng is a member of the World Meteorological Organization’s Ocean Observations Physics and Climate Panel, which evaluates the status of global ocean observation systems and recommends strategies to keep such systems sustainable.

“It’s a really important paper because it is addressing the precarity of our current global ocean observing system,” said Hilary Palevsky, a marine biogeochemist at Boston College who was not involved in the study.

Data Degradation

GOOS is a network of observing platforms, ship observations, buoys, and Argo floats that measure various essential ocean variables such as temperature, salinity, nutrients, biodiversity, and more. In particular, the network provides high-quality data on ocean heat content, a measurement of the amount of energy stored in Earth’s oceans. Scientists use ocean heat content to project global sea level rise, tropical cyclones and hurricanes, marine heat waves and their impacts on ecosystems and fisheries, and more.

“If we want to know how much the climate is impacting ocean ecosystems, we have to monitor ocean temperature and ocean heat content changes,” Cheng said.

According to Cheng, much of the information gathered about the health of ocean observation systems like GOOS is simply inventories—counts of how many observations exist. Rarely does anyone evaluate how the number of observations available affects the quality of the data, he said. And with various global threats to data stewardship and funding, making that assessment could be more important than ever.

To see how a hypothetical loss of GOOS observations could affect ocean heat content data, Cheng and the research team ran two experiments. First, they randomly removed 20%, 40%, 60%, and 80% of the available GOOS ocean heat content observations to mimic possible changes to the system. Losing these data degraded measurements of the global annual ocean heating rate in all cases, increasing the relative error of the measurement by about 33%, 57%, 79%, and 97%, respectively.

“That’s a really risky place for us as the global ocean sciences community to have any country play such a pivotal role.”

Next, they removed the datasets by country, creating hypothetical scenarios where a country’s entire contribution was deleted from the network. Removing data from the five countries with the highest contributions (the United States, Australia, Japan, France, and Germany) degraded ocean heating rate measurements significantly in each case. Removing data contributed by the United States, for example, increased the relative error of the global annual ocean heating rate measurement by 163%, making the measurement difficult to distinguish from noise.

Cheng was surprised by the extent to which losing data maintained by the United States affected ocean heat content observations. The United States contributes more than 50% of the ocean observation data in GOOS and provides crucial observational coverage of the Arctic Ocean and the tropics. “We knew it was important, but it’s even more important than we thought,” Cheng said.

“Historically, I had been proud of how much the U.S. has contributed to the ocean observing enterprise globally,” Palevsky said. But, she added, “that’s a really risky place for us as the global ocean sciences community to have any country play such a pivotal role.”

The authors write that their results may be underestimates of how data loss will affect measurement quality because in many cases, observational equipment and data infrastructure are shared between countries, meaning a change to one country’s ability to collect observations could “propagate through the system.”

The team also tested only how a loss of observations would affect ocean heat content data. Other essential variables could fare even worse because they are already limited by having fewer observations than ocean heat content, Palevsky said.

Coordination and Collaboration

Cheng said the results indicate a need for countries to collaborate more closely to ensure long-term global coverage of ocean observations. “This should be done in a much more coordinated way,” he said. The World Meteorological Organization’s Global Telecommunication System (GTS) offers a possible model, he said. To access data from GTS, a country must also contribute data.

“Some of the U.S. contributions don’t have funding to take us all the way to having those conversations [in 2029].”

Scientists, too, could coordinate better by teaming up with each other when heading out on scientific cruises, Cheng said. He imagines a global platform scientists can use to communicate to see whether their research goals and cruise routes match up with those of scientists elsewhere in the world. The ocean observation community meets every 10 years; the next meeting will occur in Qingdao, China, in 2029. Cheng said the gathering will be a good opportunity for “everyone to sit together and create a high-level agreement about how to move forward” toward better coordination. “I think we can achieve this,” he said.

However, 2029 may come too late to address some of the uncertainty facing U.S. ocean research, Palevsky said. “Some of the U.S. contributions don’t have funding to take us all the way to having those conversations [in 2029].”

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

Citation: van Deelen, G. (2026), Changes in funding could tank quality of ocean heat content data, Eos, 107, https://doi.org/10.1029/2026EO260226. Published on 13 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.

Source: Earth’s Future

This is an authorized translation of an Eos article. 本文是Eos文章的授权翻译。

航天产业正在迅猛发展。未来几年，预计将有近 10,000 颗航天器被发射至近地轨道，用于全球监测、太空旅游以及提供互联网服务的卫星“巨型星座”等多种用途。

火箭发动机的尾气，以及失效卫星和火箭部件重返地球大气层时燃烧产生的物质，都会释放出一系列污染物。鉴于航天产业以往规模较小，这些化学物质长期以来被认为对气候影响不大。如今，该行业的快速增长将导致排放量激增，但科学家目前尚未完全掌握其对环境的具体影响。

Vliex 等人对 2022 年发射的火箭进行的一项分析显示，航天活动会消耗臭氧层并加剧全球变暖。其中，很大一部分臭氧损耗归因于物体重返大气层时释放的氮氧化物。

 研究人员计算了 2022 年发射的所有 186 枚火箭以及472个重返大气层的物体所产生的排放量，这些物体总质量近 5,000 吨。他们针对每次发射的飞行轨迹及100 公里以内不同高度处的排放情况进行了计算机模拟，并计算了物体重返大气层时释放的排放量。此外，他们还考虑了火箭尾气中发生的化学反应所产生的影响，这些反应会改变排放物的化学成分。  

将计算出的排放数据纳入大气化学计算模型 GEOS-Chem后，研究揭示了这些排放物对臭氧层的消耗作用及对地球的增温效应，并确认重返大气层过程中的排放是导致臭氧损耗的关键因素。研究人员发现，将羽流反应纳入考量后，航天飞行排放物的影响估算值有所降低。这凸显了在未来评估中考量羽流化学过程的重要性。

该分析还强调了不同类型火箭燃料所产生的影响的差异。在近期NASA旨在将宇航员送回月球的“阿尔忒弥斯2号”（Artemis II）任务中，火箭助推器使用了固体燃料。数据显示，相对于推进剂的质量来说，此类燃料造成的臭氧损耗最为严重，而火箭级煤油则导致了最显著的升温效应。

基于上述研究结果，研究人员呼吁，随着航天产业的持续扩张与演变，有必要针对重返大气层的排放物及火箭羽流化学开展进一步研究。

—科学撰稿人Sarah Stanley

This translation was made by Wiley. 本文翻译由Wiley提供。

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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.

Pyrite, an iron sulfide ore, is often known as fool's gold because its shiny metallic luster and pale brass-yellow color can easily fool the untrained eye into mistaking it for real gold. This time, however, 360 kilometers (220 miles) south of Tokyo, scientists have uncovered invisible gold within pyrite structures found deep beneath the ocean at the Higashi-Aogashima Knoll Caldera hydrothermal field.

Author(s): Renat Karimov, Philippe Guittienne, Simon P. H. Vincent, Stephan Brunner, Rémy Jacquier, Christine Stollberg, Pietro Pecchini, and Ivo Furno

Collisional dissipation is expected to be the primary damping mechanism for helicon waves in low-temperature, high-density, moderate magnetic field plasmas. Combining a normal-mode analysis with high-resolution magnetic field measurements, we validate this expectation across a broad parameter space.…

[Phys. Rev. E 114, 015209] Published Mon Jul 13, 2026