Reviews of Geophysics最新文献

The Meiyu-Baiu-Changma (MBC) is a critical rainy season in East Asia. The MBC rainfall is a vital water source but also causes devastating flooding, profoundly impacting agriculture, water resource management, and socio-economy across East Asia. The El Niño–Southern Oscillation (ENSO) plays a critical role in modulating the interannual variability of MBC. The response of MBC to ENSO is, however, complex, nonlinear, and stochastic, influenced by various ENSO characteristics including the phase, intensity, location, and decay pace. This review synthesizes recent advances in understanding the ENSO–MBC linkage, by incorporating existing literature and our new analyses, to elucidate the underlying mechanisms, model performance, and future projections regarding ENSO's impacts on the MBC under climate change. In this review, an increased correlation between ENSO and MBC over past decades is revealed. The two main paths of ENSO impacting the MBC via modulating the anomalous western North Pacific anticyclone, and the changes in the influence of these paths under climate change, are synthesized and analyzed. Seasonal prediction of ENSO-driven MBC anomalies remains challenging, despite the advances of climate models in simulating and predicting the ENSO-related large-scale ocean and atmospheric circulation anomalies. In the future, intensified global warming may lead to a further strengthened impact of ENSO on MBC and increased ENSO-driven MBC extremes. Exploring greenhouse gas forcing's influence, improving high-resolution coupled models, refining representation of key dynamic processes, and utilizing artificial intelligence techniques are essential to advance understanding, simulation, prediction, and climate adaptation strategies related to ENSO-MBC connection.

Rising global temperatures pose significant risks to marine ecosystems, biodiversity, and fisheries. Recent comprehensive assessments suggest that large-scale mitigation efforts to limit warming are falling short, and all feasible future climate projections, including those that represent optimistic emissions reductions, exceed the Paris Agreement's 1.5°C or 2° warming targets during this century. While avoiding further CO₂ emissions remains the most effective way to prevent environmental destabilization, interest is growing in climate interventions—deliberate, large-scale manipulations of the environment aimed at reducing global warming. These include carbon dioxide removal (CDR) to reduce atmospheric CO₂ concentrations over time, and solar radiation modification (SRM), which reflects sunlight to lower surface temperatures but does not address root CO₂ causes. The effects of these interventions on marine ecosystems, both direct and in combination with ongoing climate change, remain highly uncertain. Given the ocean's central role in regulating Earth's climate and supporting global food security, understanding these potential effects is crucial. This review provides an overview of proposed intervention methodologies for marine CDR and SRM and outlines the potential trade-offs and knowledge gaps associated with their impacts on marine ecosystems. Climate interventions have the potential to reduce warming-driven impacts, but could also alter marine food systems, biodiversity and ecosystem function. Effects will vary by pathway, scale, and regional context. Pathway-specific impact assessments are thus crucial to quantify trade-offs between plausible intervention scenarios as well as to identify their expected impacts on marine ecosystems in order to prioritize scaling efforts for low-risk pathways and avoid high-risk scenarios.

Mountain glaciers are among the natural systems most vulnerable to climate change. However, their interactions with the atmosphere are complex and not fully understood. These interactions can trigger rapid adjustments and climate feedbacks that either amplify or attenuate atmospheric signals, influencing both glacier response and large-scale atmospheric circulation. Observing this functional coupling in nature is challenging because the key processes occur over a wide range of spatial and temporal scales. However, recent advances in observational techniques and modeling have provided new insights into these interactions. In this review, we summarize the current state of knowledge on glacier-atmosphere interactions in high-mountain regions at different scales, and highlight recent advances in observational and numerical modeling. We also highlight important knowledge gaps and outline future research directions to improve the prediction of glacier change in a warming world.

Frozen soils, including seasonally frozen ground and permafrost, are rapidly changing under a warming climate, with cascading effects on water, energy, and carbon cycles. We synthesize recent advances in the physics, observation, and modeling of frozen-soil hydrology, emphasizing freeze–thaw dynamics, infiltration regimes and preferential flow, groundwater–permafrost interactions (including talik development and advective heat), and resulting shifts in streamflow seasonality. Progress in in situ sensing, geophysics, and remote sensing now resolves unfrozen water, freezing fronts, and active-layer dynamics across scales, while land-surface and tracer-aided hydrological models increasingly represent phase change, macropore bypass, and vapor transport. Thaw-induced activation of subsurface pathways alters recharge and baseflow, influences vegetation and biogeochemistry, and modulates greenhouse-gas emissions. Key uncertainties persist in scaling micro-scale processes, parameterizing ice-impeded hydraulics, and representing abrupt thaw and wetland dynamics. We outline a tiered modeling framework, priority observations, and integration of vegetation–hydrology–carbon processes to improve projections of cold-region water resources and climate feedbacks.

The increasing threat of soil degradation presents significant challenges to soil health, especially within agroecosystems that are vital for food security, climate regulation, and economic stability. This growing concern arises from intricate interactions between land use practices and climatic conditions, which, if not addressed, could jeopardize sustainable development and environmental resilience. This review offers a comprehensive examination of soil degradation, including its definitions, global prevalence, underlying mechanisms, and methods of measurement. It underscores the connections between soil degradation and land use, with a focus on socio-economic consequences. Current assessment methods frequently depend on insufficient data, concentrate on singular factors, and utilize arbitrary thresholds, potentially resulting in misclassification and misguided decisions. We analyze these shortcomings and investigate emerging methodologies that provide scalable and objective evaluations, offering a more accurate representation of soil vulnerability. Additionally, the review assesses both physical and biological indicators, as well as the potential of technologies such as remote sensing, artificial intelligence, and big data analytics for enhanced monitoring and forecasting. Key factors driving soil degradation, including unsustainable agricultural practices, deforestation, industrial activities, and extreme climate events, are thoroughly examined. The review emphasizes the importance of healthy soils in achieving the United Nations Sustainable Development Goals, particularly concerning food and water security, ecosystem health, poverty alleviation, and climate action. It suggests future research directions that prioritize standardized metrics, interdisciplinary collaboration, and predictive modeling to facilitate more integrated and effective management of soil degradation in the context of global environmental changes.

For decades it has been observed that rates of silicate mineral reactions appear slower in field settings than when measured in the laboratory. Since the 1980s, researchers have proposed explanations for the discrepancy. Over that time, researchers have also advanced the state of laboratory and field rate measurements as well as models of mineral-water reaction kinetics at different temporal and spatial scales. Developments in reactive transport modeling are constantly whittling away at the discrepancy as models are improved, coupled to hydrologic models, and driven by climate data. The lab-field discrepancy has great relevance today because of the proposal that weathering of silicates (especially basalts) could be accelerated to remove CO₂ from the atmosphere and sequester it either as aqueous alkalinity or as carbonate mineral precipitate. Such “enhanced rock weathering” relies on mining and grinding silicate rock for dispersal on farmland to enable weathering by carbonic acid. In general, field rates become increasingly slower than lab rates at larger spatial and temporal scales because of factors related to surface area, hydrology, heterogeneities, biota, and system-level effects. This implies surface area is not always an appropriate scaling factor. The measurements of enhanced rates of basalt weathering on croplands published so far are relatively consistent with previously published lab and field rates of basalt weathering because the durations of weathering are small. But the rates of CO₂ consumption from the atmosphere are very slow, and will decrease with time, necessitating huge acreages of basalt spreading to reach gigatons of CO₂ sequestration.

The terrestrial planetary bodies of our solar system—Mercury, Venus, Earth, and Mars—share a common origin through nebular accretion and early magma ocean differentiation, yet they diverged significantly in geological evolution, tectonic regimes, and habitability. Differences include distance from Sun, size, mechanism of internal cooling, degassing record, and resultant surficial conditions. Mercury, Mars, and Earth's Moon preserve largely mafic crust formed early in their evolution in a stagnant lid setting. Venus and Earth with their larger size record a long history of tectonic activity. Venus's mafic crust underwent large-scale resurfacing in the last billion years, likely in a stagnant lid setting but with potential areas of squishy lid behavior. The Earth preserves a long-lived plate tectonic regime in which young mafic crust beneath oceans is continually generated and recycled, whereas felsic crust forms emergent continents and spans much of the planet's history. The Earth is also characterized by a persistent magnetic field and a complex biosphere. Variations in tectonic modes between the terrestrial planets impact volatile exchange, magmatic outgassing, nutrient recycling and, in the case of Earth, provision of ecological niches. Other planets experienced transient habitability or remained uninhabitable, largely due to early cessation of tectonic and magnetic activity or atmospheric loss. Life may emerge under stagnant lid conditions, but sustained habitability and biological diversification require continued geological activity and crustal emergence. Insights from the terrestrial planets inform the search for habitable exoplanets, highlighting the intertwined roles of planetary interiors, surface processes, and atmosphere-crust interactions in shaping life-supporting environments.

Selenium (Se) is essential for human health. Organisms produce volatile Se through metabolism, which is an essential but hidden component of the Se geochemical cycle. Understanding this natural cycle is vital for sustainable development and ecosystem protection, thereby preserving planetary health and fostering harmonious coexistence between the environment and humanity. This review explores sampling methods and environmental behavior of volatile Se. It emphasizes the species and volatilization amounts of selenium in water, sediments, and soil. Furthermore, it highlights that future research should focus on agricultural fields and climate-sensitive areas (such as wetlands, polar regions, alpine regions, and plateaus). Additionally, the review addresses the risks associated with Se volatilization under climate change. By summarizing current knowledge and identifying research gaps, this work offers suggestions for future research directions in Se biovolatilization and provides a foundation for developing strategies to regulate Se distribution in soil.

Dielectric anisotropy in ice alters the propagation of polarized radio waves, so polarimetric radar sounding can be used to survey anisotropic properties of ice masses. Ice anisotropy is either intrinsic, associated with ice-crystal orientation fabric (COF), or extrinsic, associated with material heterogeneity, such as bubbles, fractures, and directional roughness at the glacier bed. Anisotropy develops through a history of snow deposition and ice flow, and the consequent mechanical properties of anisotropy then feed back to influence ice flow. Constraints on anisotropy are therefore important for understanding ice dynamics, ice-sheet history, and future projections of ice flow and associated sea-level change. Radar techniques, applied using ground-based, airborne, or spaceborne instruments, can be deployed more quickly and over a larger area than either direct sampling, via ice-core drilling, or analogous seismic techniques. Here, we review the physical nature of dielectric anisotropy in glacier ice, the general theory for radio-wave propagation through anisotropic media, polarimetric radar instruments and survey strategies, and the extent of applications in glacier settings. We close by discussing future directions, such as polarimetric interpretations outside COF, planetary and astrophysical applications, innovative survey geometries, and polarimetric profiling. We argue that the recent proliferation in polarimetric subsurface sounding radar marks a critical inflection, since there are now several approaches for data collection and processing. This review aims to guide the expanding polarimetric user base to appropriate techniques so they can address new and existing challenges in glaciology, such as constraining ice viscosity, a critical control on ice flow and future sea-level change.

Oxychlorine species (mainly perchlorate and chlorate) have been identified at multiple locations on the surface of Mars by both orbiter and in situ rovers. They have also been found in martian meteorites. Cl-isotopes in meteoritic minerals suggest that an oxychlorine cycle has been operating on the martian surface for the last ∼4 billion years. The present surface conditions are more favorable for their formation than the past and a multitude of formation pathways are likely responsible for their accumulation on Mars. Isotopic analysis of Cl and O can help constrain oxychlorine formation processes. Once formed, oxychlorine species accumulate on the surface as salts or brines, and drive critical geochemical processes. Oxychlorine salts can absorb water from the thin martian atmosphere to form transient brines and percolate into the subsurface. Chlorate anion is an effective oxidizing agent and likely contributes to oxidizing organic matter, iron and manganese minerals on Mars. Given their detection at multiple locations coupled with their ability to stabilize liquid water, oxidize redox-sensitive elements, and promote anaerobic respiration for certain terrestrial microorganisms, oxychlorine compounds have important implications for martian geochemistry and astrobiology, both in the past and in the present. Their propensity to form highly oxidizing brines in closed system environments makes them a critical compound under consideration during the Mars Sample Return mission. This article reviews oxychlorine detection, formation, destruction, and implications on Mars, and identifies potential areas of future research.