The QuikSCAT satellite radar scatterometer has observed parallel bands of negative and positive wind stress curls on the inshore and offshore sides of the Kuroshio in the East China Sea, which were not seen in other low-resolution wind products. This study assesses the impact of these small-scale wind variations on ocean simulations by comparing two numerical experiments forced by monthly climatological wind with and without this small-scale component in an eddy-resolving ocean model. By affecting the Ekman upwelling and downwelling, the wind stress curls influence the temperature structure and ocean current. The results show that these small-scale wind variations can reduce the Kuroshio velocity on the onshore side and increase it on the offshore side, accompanied by a systematic cooling of the sea surface temperature (SST) along the Kuroshio path. Although these small-scale winds are prescribed in the East China Sea, they have a significant influence on the downstream surface kinetic energy south of Japan by affecting the state of the Kuroshio. These small-scale wind variations also modulate the seasonal variability of the Kuroshio. The results of this study help to understand various ocean simulations subjected to different wind stress products.
Anthropogenic warming is expected to intensify tropical cyclone rainfall, yet how this intensification translates into flood peaks across complex river networks remains poorly understood. In this study, we employed a WRF-forced WRF-Hydro modeling framework using a Pseudo-Global Warming approach to quantify the propagation of intensified rainfall from tropical cyclone Hinnamnor in 2022 under historical (SST-1860), current, and future (SST-2050, SST-2090) sea surface temperature (SST) conditions. While basin-mean runoff increases by about 24–49
Soil moisture (SM) is a critical land surface variable that modulates land–atmosphere interactions through the partitioning of surface energy and moisture fluxes. This study examines the sensitivity of forecasts of poleward-moving, landfalling tropical cyclones (TCs) to initial SM condition. We conducted Weather Research and Forecasting (WRF) model experiments for three recent TCs that affected South Korea using initial SM from the Global Land Data Assimilation System (GLDAS) Noah v2.1 and the European Centre for Medium-Range Weather Forecasts Reanalysis v5 (ERA5), hereafter referred to as the GL and ERA5 runs, respectively. The ERA5 run maintained positive SM differences relative to the GL run over a trough-development region spanning Northeast China and adjacent Mongolia, although the differences were spatially heterogeneous across the broader land domain. The GL runs had smaller landfall-period track errors in the three selected cases, with the clearest separation for Hinnamnor. During the later forecast period, the ERA5 run produced a westward-to-northwestward track displacement relative to the GL run, accompanied by a deeper, more westward-displaced mid-latitude trough and a modified upper-level steering environment. Process-oriented diagnostics indicate a physically consistent sequence linking persistent differences originating from the SM initialization to surface flux and moist thermodynamic responses, stronger ascent, trough modification, steering flow differences, and the simulated TC track response. These results demonstrate sensitivity of medium-range mid-latitude circulation and poleward-moving TC track forecasts to the prescribed initial SM condition.
Abstract Southern Ocean (SO) sea salt aerosol is key to Earth’s energy budget, but its future changes are highly uncertain. Here using a 40-member ensemble from the Community Earth System Model Large Ensemble (CESM1-LE) project, we find that projected SO sea salt is modulated by internal climate variability both locally in the SO and remotely from the tropical Pacific. The leading mode of inter-member diversity displays a zonally homogenous pattern associated with the Southern Annular Mode due to its impact on future westerly poleward intensification. The second largest source of inter-member uncertainty relates to El Niño-Southern Oscillation (ENSO). In particular, as El Niño and La Niña are not symmetric, the cumulative ENSO impact on SO winds exhibits a meridional dipole in the south Pacific, such that a stronger future ENSO with more extreme El Niño events will induce a larger zonally heterogenous distribution of SO sea salt. Our results uncover an important role of ENSO nonlinearity in projected SO sea salt aerosol distribution.
Abstract The ocean plays a crucial role in the formation and melting of sea ice, which also affects the performance of sea ice data assimilation. To evaluate how ocean model complexity affects the assimilation performance, the sea ice model is separately coupled with two distinct ocean models. In this study, the satellite-derived sea ice concentration and thickness data in the Arctic are assimilated into a coupled sea ice-ocean model, using the ensemble Kalman filter (EnKF) approach. Utilizing a fully dynamic ocean model effectively mitigates ensemble convergence during the Arctic freezing season compared to a simplified ocean model, thereby improving the performance of sea ice data assimilation. However, when only sea ice concentration data are assimilated, an anomalous spatial pattern in sea ice thickness emerges in the Arctic, regardless of the type of ocean model. This abnormal pattern is effectively resolved through the joint assimilation of satellite-derived sea ice concentration and thickness data, leading to improved consistency in Arctic sea ice state estimation.
Aesthetics, traditionally understood as a subjective value in the evaluation of nature, was historically treated as a secondary criterion in classical studies on the valuation of geoheritage. However, recent advances indicate a paradigmatic shift, in which aesthetics is now recognized as a central value, aligning with the criteria adopted by UNESCO for the recognition of sites of outstanding universal value, such as Criteria vii, which emphasizes natural beauty and the aesthetic importance of landscapes. This article aims to demonstrate the centrality of the aesthetic dimension through a systematic review with a bibliometric approach. The methodology was based on data collection from the Scopus database, from which the most relevant works published between 2021 and 2025 were selected. Focusing on citation metrics, the 10 most cited studies were identified, of which 6 directly address aesthetics as a structuring dimension in geoheritage assessment, highlighting its growing relevance in the field. The findings demonstrate an important theoretical transition, in which aesthetics shifts from a complementary attribute to a central position in evaluation models, particularly in studies related to geotourism and territorial valorisation. Previously marginalized, aesthetics now assumes a strategic role in geoheritage assessment, reinforcing its importance in the conservation and valorisation of geodiversity on a global scale.
Institutional conflicts of interest constrain regional water management in metropolitan systems supplied by multiple reservoirs and operated by separate utilities. Such conflicts arise when decentralized utilities pursue cost-minimizing strategies that diverge from system-wide reliability and social welfare objectives. This study examines these dynamics in the Taipei metropolitan water supply system, where two reservoirs with contrasting hydrological reliability are physically connected through a cross-basin water transfer infrastructure intended to rebalance regional allocation. A deterministic scenario-based analysis using the Water Evaluation and Planning (WEAP) model is conducted under varying hydrological stress regimes to evaluate alternative allocation priorities and pricing structures. The analysis links hydrological conditions, infrastructure operation, and utility-level financial incentives to system-level social loss. Results indicate that pricing and transfer-payment adjustments can align institutional incentives with socially preferred outcomes when scarcity is localized and overall system reliability is maintained. However, when severe drought affects the historically more reliable subsystem, pricing mechanisms alone become insufficient to prevent socially suboptimal allocation. These findings demonstrate that physical integration without incentive alignment does not guarantee effective coordination and clarify the conditions under which pricing instruments can mitigate institutional conflict in regional water systems.
Abstract The interaction between glaciers and the atmosphere is generally recognized to affect melt rates, surface energy budgets, and even short-lived weather extremes in high mountain ranges. However, the Himalayan system remains hard to observe due to steep terrain and very few long-term data from the glacier surface. In winter, conditions in valleys such as Hunza or in the central Karakoram are not conducive to keeping instruments intact, increasing the uncertainty about how latent and sensible heat fluxes contribute to snow and ice melt, local moisture behavior, and temperature regimes. Recent observations in the field and model results indicate that turbulent heat exchange can drive glacier cooling and sublimation and can generate small-scale feedbacks that may interact with regional flow. At the same time, uncertainties persist linked to sparse measurements, debris-covered glacier surfaces, and a loose connection between atmospheric and cryospheric models in complex terrain. This review synthesizes current knowledge on turbulent heat flux dynamics in the Himalayas, with brief excursions into the Andes, Alps, and other cold mountain systems. The objective is to identify the key processes driving melt and to reveal the gaps that hinder confident projections of meltwater and climate sensitivity in High Mountain Asia.
Abstract Accurate assessment of the changing thermal structure of megathrusts at the global scale is difficult because the subduction regime depends on the three-dimensional (3-D) geometry of slabs. Although the slab dip has been studied extensively, the specific implications of subduction geometries have not been well assessed. In this study, we propose an integrated thermal model that can be used to infer and quantify the ways in which the slab morphology influences the thermal state of the incoming plate below Hokkaido. Our model accounts for both the slab topography and subduction obliquity variations along the trench. The results reveal correspondence between the temperature structure, water content distribution, and observations of subduction earthquakes. Moreover, the results suggest that the primary episode of dehydration below Hokkaido occurs between depths of ~ 40 and 100 km, with temperatures ranging from 300 °C to > 700 °C, where the metamorphic transition of basaltic crust from greenschist to amphibolite and ultimately to eclogite facies induces massive water release, yielding the occurrence of most earthquakes. A dehydration belt with a rate exceeding 0.05 wt%/km occurs at the lower limit of the seismic zone. The rate is notably higher near the bending of the trench, where plate bending generates fractures that facilitate seawater penetration and cause serpentinization. The thermal shielding effect originating from the subducting cold oceanic plates results in low surface heat flow (< 80 mW/m2) in the forearc region of Hokkaido, whereas magmatic and hydrothermal activities induced by slab dehydration and melting cause significantly elevated heat flow, with localized anomalies > 120 mW/m2 near volcanic arcs.
Abstract The Agulhas Return Current (ARC) transports warm, salty subtropical waters eastward into the South Indian Ocean, where it meets cold, fresh Southern Ocean waters to the south, creating strong meridional surface temperature and salinity gradients. Analysis of Argo data reveals coherent interannual variations in surface temperature (~ 1 °C) and salinity (~ 0.2 g/kg) downstream of the ARC from 2004 to 2023. Further analysis indicates that these variations are primarily driven by large-scale westerly wind fluctuations associated with the Southern Annular Mode (SAM). During positive SAM phases, the southward shift of westerlies weakens wind speed over the ARC region. This reduces northward Ekman advection of cold, fresh water, resulting in surface warming. Conversely, during negative SAM phases, the northward movement of westerlies enhances wind speed, enhancing Ekman advection and cooling the surface. These findings underscore the dominant role of meridional Ekman advection in driving hydrographic properties variability in the ARC region.
Abstract Eddies play an important role in the regulation of oceanic heat redistribution. This study investigates and analyzes submesoscale eddies in the upper ocean from the edge of the Beaufort Shelfbreak to the southern Canada Basin using data from the MITgcm LLC4320 model, focusing on their spatiotemporal distribution, trajectories, heat content, and variations in anomalous heat content. The results indicate that eddy activity within the jet region exhibits seasonal variation. Eddy counts peak in the spring months (April-June) and gradually decreases through summer to early autumn (August-November). Following their formation near the shelfbreak, cyclonic submesoscale eddies tend to propagate along the jet. Conversely, anticyclonic submesoscale eddies are more likely to detach from the jet region. It is estimated that approximately 44% of anticyclonic submesoscale eddies migrate northward into the southern Canada Basin, thereby serving as key submesoscale carriers for transporting shelfbreak waters into the basin. A marked seasonal temperature disparity exists between the shelfbreak waters and the basin. Consequently, anticyclonic submesoscale eddies formed during the summer months typically exhibit warm cores. Conversely, those formed in winter are predominantly cold-core. Environmental factors during the formation and evolution of submesoscale eddies have been shown to cause significant variability in the thermal structure among individual anticyclonic submesoscale eddies. Specifically, among the anticyclonic submesoscale eddies generated in the jet region that subsequently enter the basin, anticyclonic cold-core submesoscale eddies exhibit heat content differences of approximately − 26.5 × 1015 J to -2.2 × 1015 J, whereas anticyclonic warm-core submesoscale eddies show differences of 11.0 × 1015 J to 16.1 × 1015 J. Assuming an idealised scenario, cold-core eddies have the potential to influence the formation of sea ice within an area ranging from 6 to 77 km², with a mean of 33 km². In contrast, warm-core eddies have the capacity to affect the melting of sea ice over an area of 32–47 km², with a mean of 40 km². The results obtained suggest that anticyclonic submesoscale eddies play a role in regulating the upper-ocean heat distribution and sea-ice growth and melt processes in the Canada Basin.
Abstract This study presents a deep learning framework to objectively classify Pre-Meiyu season synoptic weather types and their linkage to regional rainfall patterns. Using ERA5 reanalysis (1979–2023), we employ a suite of Convolutional Neural Network (CNN)-Autoencoders to extract latent features from 5-day moving mean atmospheric circulation fields. These features are utilized to objectively identify the duration of the Pre-Meiyu season via cosine similarity. Within this season, a set of CNN-Autoencoders is trained to extract latent features from daily mean atmospheric variables (ERA5) and daily rainfall (GPM IMERGE, TCCIP; 2001–2023). Unsupervised k-means clustering of these features identifies eight distinct synoptic weather types. Four types are associated with significant rainfall over Taiwan and are directly influenced by frontal systems and/or southwesterly flow. The other four correspond to drier conditions governed by the relative positions of the monsoon trough and subtropical high. Notably, a distinct type characterized by a southward-shifted southwesterly flow is linked to tropical cyclone activity. Subsequently, these latent features serve to train six machine learning classifiers to categorize daily weather types. The Ensemble Voting Classifier (EVC) demonstrates robust performance, with its accuracy, F1-score, and precision all exceeding 0.9. Compared to individual models, the EVC improves overall mean scores while providing more consistent classifications, effectively reducing performance variability even for weather types where single models exhibited instability. These results demonstrate that combining deep learning feature extraction with an ensemble classifier provides a robust and accurate method for objectively characterizing Pre-Meiyu season weather systems.
Abstract The ocean serves as the energy source for tropical cyclones (TCs), and a TC typically encounters multiple oceanic warm and cold events during its lifecycle. While most existing studies emphasize individual thermal events, the net contribution of multiple warm and cold events to TC intensity remains unclear. We use a set of idealized coupled atmosphere–ocean simulations to examine how multiple ocean warm and cold thermal events affect TC intensity evolution throughout its lifecycle. Based on observational evidence, our experimental design includes one control experiment and 30 sensitivity experiments across three core scenarios (warm-anomaly dominated, cold-anomaly dominated, and warm-cold balanced anomalies). Relative to the control experiment, warm dominated experiments produce a stronger intensity evolution, cold dominated experiments produce a weaker decay, and the balanced experiments also lead to a slight increase. This response is fundamentally asymmetric, as the intensifying influence of warm events outweighs the weakening influence exerted by cold events with comparable magnitude. Moreover, this asymmetry increases with the magnitude of the oceanic thermal anomalies, and when the warm-anomaly amplitude is doubled, the simulated TC satisfies the rapid intensification criterion. These findings quantify the asymmetric forcing of ocean thermal structures on TCs, providing a crucial mechanistic basis for improving TC intensity forecasts.
Abstract Climate change influences weather patterns induced by large-scale circulation, leading to changes in wind and precipitation. Consequently, aerosol transport patterns are thought to be shifted, thereby influencing the movement of air pollutants through environment-climate interactions. However, the long-term trends and mechanisms driving the shifts in transboundary air pollution pathways remain unclear, particularly in the downwind region around East Asia. Here, we investigated recent decadal trends in transboundary air pollution pathways by applying $$\textit{R}_{\text {AOD}}$$ , a new metric that quantifies the long-term variations in these pathways. By combining reanalysis and satellite products, we demonstrated how the decadal trends of $$\textit{R}_{\text {AOD}}$$ characterize the shortening of the eastward aerosol transport distance. Our analyses revealed that although the aerosol composition exerts a minor influence on transport, changes in precipitation and circulation, even near source regions, have played a major role in aerosol climatology. This emphasizes that climate-driven circulation shifts may redefine global pollution transport.
Abstract Convectively forced gravity waves (CGWs) play important roles in the atmosphere. CGW drag parameterizations for use in large-scale models typically represent subgrid-scale convection as a single convective source. This study uses an analytic framework to investigate how horizontal organization of multiple convective cells modifies the vertical flux of horizontal momentum. It is shown that the per-cell momentum flux induced by multiple convective cells is expressed as the momentum flux induced by a single convective cell times [1 + J n (β, δ)]. Here, J n (β, δ) is the nonlinear modification factor arising from mutual interactions among distinct convective cells, where β is the ratio of compensating-cooling width to heating-core width, δ is the nondimensional spacing between the horizontal centers of convective cells, and n is the number of cells. Closely packed deep convective cells with broad cooling (large β and small δ) act to enhance the per-cell momentum flux relative to a single convective cell, whereas more widely spaced convective cells act to reduce it. As the number of convective cells increases, the region of positive J n in the parameter space of β and δ shrinks toward smaller δ. These results indicate that purely geometric properties of convective organization (β, δ, and n) systematically modify CGW momentum flux. The proposed nonlinear modification factor can be easily incorporated into existing CGW drag parameterizations.
Abstract This study investigates the ionospheric saturation effect in the total electron content (TEC) response to solar activity using long-term global ionospheric map data spanning 1999–2024. Empirical mode decomposition is used to isolate long-term solar-cycle variability, and a two-segment regression model provides a consistent diagnostic of the saturation threshold in TEC versus solar proxy F10.7p. The global distribution exhibits pronounced local-time and seasonal patterns, with strong occurrence at low latitudes during equinoxes and enhanced mid- and high-latitude occurrence in the summer hemispheres during solstice seasons. Although saturation is most pronounced within localized high-density structures such as the Equatorial Ionosphere Anomaly, Weddell Sea Anomaly, and Yakutsk Anomaly regions, the broader hemispheric occurrence, particularly in the summer hemispheres, shows only weak correlations with TEC, suggesting that additional drivers such as neutral winds and composition changes must also be considered.
Abstract This study systematically analyzes the size distribution, concentration characteristics, atmospheric sources, and their coupling relationships with hydrochemical components of dust particles in glacial ice and meltwater from the Mingyong Glacier on the southeastern margin of the Tibetan Plateau. It reveals the transport patterns, source characteristics, and coupling relationships with hydrochemical components of local dust particles. The results indicate: (1) The average size (i.e., particle diameter) (2.01 μm), number concentration (1622.19 × 104 mL−1), and mass concentration (2699.32 × 104 µg kg−1) of dust particles in glacial ice are significantly higher than those in meltwater (1.63 μm, 551.75 × 104 mL−1, and 251.57 × 104 µg kg−1, respectively), with the hydraulic sorting effect of meltwater being an important mechanism for this difference. (2) Meltwater dust particle exhibits a unimodal distribution throughout the year (median size 14.15 μm) with relatively homogeneous sources, while glacial ice dust particle shows a multimodal distribution during the accumulation period, indicating more complex sources. (3) Backward trajectory analysis indicates that dust particle during the accumulation period is primarily transported over long distances (Central Asia, Southwest Asia), controlled by stable westerly circulation, while during the ablation period, it is mainly from local Tibetan Plateau and neighboring areas via short-range transport, influenced by the interaction between westerlies and monsoons. (4) Hydrochemical analysis shows that ions in the water primarily originate from carbonate and silicate rock weathering. Correlation and wavelet coherence analyses reveal that the mass concentration of dust particle in glacial ice is significantly positively correlated with TDS (Total Dissolved Solid) and major ions, with coherence periods of 2–4 days or 4–8 days and phase lags at different times. The number concentration of dust particles in meltwater is significantly positively correlated with regional air temperature and precipitation, with temperature consistently leading the dust concentration. This study clarifies that dust particles in the Mingyong Glacier are influenced by both regional and distant sources, and their release process is closely coupled with glacier ablation, hydrological processes, and seasonal shifts in atmospheric circulation. It provides data support for further understanding the glacier-dust-climate interaction mechanisms in the southeastern Tibetan Plateau.
This Special Collection comprises twenty-one papers on the tectonic, magmatic, paleoclimate, and environmental evolution of the Taiwan-Philippine arc system and the Japanese islands. The Collection mainly focuses on the tectonic, geological, and eruptive histories of the Philippines and Taiwan. Several papers investigate the complex geological and tectonic histories of Taiwan and the Philippines, with an emphasis on crustal thickness, active tectonics, island-arc formation, and basin development. Other papers examine rapid exhumation, erosion, and seismic and aseismic motions resulting from convergence between the Eurasian and Philippine Sea Plates in this region. By integrating advanced geochronological dating, isotopic analyses, and geophysical data, these papers address fundamental questions about crustal growth, fault behavior, paleoenvironmental shifts, and related topics in the Taiwan-Philippine arc system.
Abstract Landslides remain a significant hazard across the Indian Himalayan regions, where steep slopes, episodic rainfall, and man-made constructions contribute to slope instability. Accurate prediction remains a challenge due to data imbalance, environmental variation, and the limited interpretability of predictive models. This study presents LogISEL, an interpretable ensemble framework designed for real-time landslide prediction at a ten-minute horizon using multi-sensor field data. The proposed framework is tested at two geologically different sites—Griffon Peak and Ghora Farm in Himachal Pradesh. LogISEL integrates six machine learning classifiers through a logistic regression meta-learner, allowing transparent and temporally coherent predictions. Compared with state-of-the-art baselines, LogISEL achieved up to 15% improvement at Griffon Peak and over 20% at Ghora Farm, without requiring artificial balancing of the inherently imbalanced dataset. SHAP-based interpretability analysis revealed that location-specific precursors, such as temperature lags in alpine terrain and light–pressure variations in cultivated slopes, dominate the prediction of slope movements. These features control predictions with respect to movement. These findings underscore the model’s adaptability and interpretability, addressing critical shortcomings of the existing ML and physics-based approaches. Overall, LogISEL represents a significant step toward designing efficient early-warning systems within landslide-prone regions, offering a transferable framework for integrating data-driven prediction with decision support in complex geophysical environments.
Abstract Establishing a robust sediment chronology in the Antarctic continental margin remains challenging because planktonic foraminifera, the primary material for accelerator mass spectrometry(AMS) 14C dating, are often absent, poorly preserved, or affected by old carbon. Previous studies have indirectly assigned interglacial sediments on the Bellingshausen Sea continental rise to Marine Isotope Stage (MIS) 5, largely based on tephra stratigraphy. However, recent AMS 14C dating from foraminifera and acid-insoluble organic matter (AIOM) in core BS17-GC02 indicates significantly younger ages, suggesting that the conventional tephra-based chronology requires reassessment. This study analyzes AMS 14C ages of planktonic foraminifera, magnetic susceptibility, CaCO3 concentration, color reflectance, and geochemical proxies from additional sediment cores (BS17-LC03 and BS17-GC04) collected from the Bellingshausen Sea continental margin to investigate these discrepancies. The results show that CaCO3 peaks and well-preserved foraminifera in the brownish interglacial layers yield calibrated AMS 14C ages of 32.9–39.1 ka. This conflicts with prior tephra chronology, which implied that deposition occurred during MIS 5, rather than suggesting that these distinctive intervals align with the later MIS 3 interglacial. Anomalously old tephra-derived ages may either result from sedimentary reworking or delayed tephra deposition. This research emphasizes the need for multi-proxy approaches and additional radiocarbon dating to obtain robust age control for Antarctic sedimentary records.
