Atmospheric and Oceanic Sciences

The albic horizon is a bleached diagnostic layer formed through combined processes of iron-manganese leaching and clay illuviation. Its thickness and burial depth collectively determine the critical role in impeding water movement and restricting root extension. However, understandings of the spatial variation of the albic horizon remain limited. Traditional understandings primarily rely on extensive field surveys combined with geostatistical methods. To expand such understandings on a broader geographical area, we developed a digital soil mapping (DSM) framework to predict the thickness and burial depth of the albic horizon. We integrated 111 soil profile points containing albic horizons with a rich set of environmental covariates to construct reliable prediction models. Following the feature selection process of recursive feature elimination (RFE), a quantile regression forest (QRF) model was employed for spatial prediction, cross-validation, and uncertainty estimation. The results from 50 repetitions of 10-fold cross-validation demonstrated robust model performance, with R² of 0.38 and 0.29 for thickness and burial depth, respectively, and RMSE% accounting for 34% and 38% of their mean values. The prediction interval coverage percentage (PICP) indicated that approximately 86.9% and 90.6% of the validation samples for thickness and burial depth, respectively, fell within the predefined 90% prediction interval (PI), affirming the reliability of uncertainty estimation. The relative variable importance indicated that climate factors were the dominant determinants in predicting both albic horizon thickness and burial depth, highlighting the necessity of incorporating climate data in the spatial modeling of albic soils. The prediction maps indicated a general decreasing trend in both the thickness and burial depth from northeast to south across the study area. Large prediction uncertainty mainly occurred in areas where soil survey points were lacking, highlighting the need for targeted supplementary surveys. Our findings offer valuable references for other similar large-scale mapping of soil layer thickness (or depth) in plain agricultural regions.

The Dyrfjöll ridge represents the remnant of the filling of a Neogene volcanic caldera. The volcanic succession consists of a basal ignimbrite overlain by basaltic hyaloclastites and capped by basaltic lavas. The ridge is truncated by the Dyr Pass (856 m a.s.l.), which formed when a major rock avalanche (RA), composed of hyaloclastites and lava blocks, collapsed from both flanks of the ridge. On the eastern side, the RA partly overrode the Dyrajökull glacier along the Jökuldalur valley. About 4 km downstream at the valley outlet, a well-preserved RA deposit remains, characterized by hummocky mounds of lava and hyaloclastite megablocks. Between this deposit and the present-day glacier fronts, six push-moraine complex ridges are preserved. The aim of this study is to establish the chronology of these glacier stages in Jökuldalur and to distinguish their different origins. To constrain the timing of deposition, 20 boulders were sampled for 36 Cl cosmogenic exposure dating from both the RA deposit and the moraine ridges. The main RA yielded an exposure age of 9.4 ± 1.1 ka. The four outermost glacial stages, represented mainly by hummocky moraine assemblages, yield ages ranging from 8.8 ± 0.9 to 6.2 ± 0.7 ka. The ages of the moraines are coeval with the Holocene Thermal Maximum, a period during which most Icelandic glaciers experienced substantial retreat or complete disappearance. The results emphasise the insulating effect of debris following RA emplacement, which appears to have promoted subsequent glacier re-advance despite prevailing peak Holocene warmth. Stage 5 yields an age of 4.0 ± 0.5 ka and is likely associated with a distinct RA event, whereas Stage 6 is younger than 0.13 ka.

Accurate characterization of heavy petroleum fractions remains challenging in hydroprocessing reactor modeling, where reliable hydrogen-solubility estimates in complex hydrocarbon mixtures are essential. Continuous thermodynamics has been successfully applied to represent crude oils and petroleum fractions in vapour-liquid equilibrium calculations through continuous composition distributions. Building on this framework, we propose a continuous-thermodynamics-based characterization methodology for vacuum gas oils and integrate it with the Augmented Grayson-Streed (AGS) approach to predict hydrogen solubility. Over temperature and pressure ranges of 459-653 K and 1.0-12.5 MPa, respectively, the proposed strategy reduces the global average absolute deviation with respect to experimental data from 22.5% to 11%. Beyond improving accuracy, the framework provides a systematic route to define a minimal set of pseudocomponents, reducing arbitrariness in heavy-fraction characterization while relying only on routinely measured laboratory data.

Fossils of the Ediacara Biota preserve the oldest macroscopic communities that include animals. Classification of many of these taxa has proved contentious. Instead, studies of ecological characters reveal key insights. Here we examine the Ediacaran fossil Spriggina floundersi from the Ediacara Member, Flinders Ranges and surrounding region. Specimens from Nilpena Ediacara National Park (NENP) and the South Australia Museum (SAM) present significant morphological variation. Fossils found in situ on discrete bedding planes at NENP reveal no systematic orientation of features, suggesting variable morphologies formed via biological processes, rather than external forces. Our results support motility in Spriggina, which involved bending about the long axis, propagation of pedal waves, vertical adjustment of the anterior region and horizontal manipulation of repeated body units. A significant number of fossil specimens are bent to the left (right in life). The nature of these bends does not match expectations of anatomical asymmetry and instead constitutes the oldest described evidence of behavioural handedness. Results are consistent with Spriggina as a bilaterally symmetrical, possibly segmented, benthic organism. These characters are unique compared with known Ediacaran ecologies but are common in various extant bilaterian groups, indicating major animal innovations prior to the Phanerozoic.

This research provides novel insights into the diversity of DNA extracted from samples collected from the Turin Shroud in 1978, revealing its biological complexity through rigorous DNA and metagenomic analyses. Our findings highlight its preservation conditions and environmental interactions, offering valuable perspectives into the identified genetic variants, which originated from multiple biological sources. We identified several human mitochondrial DNA (mtDNA) lineages, including K1a1b1a, which matches the 1978 official collector's mitogenome, H2a2 (i.e., the lineage of the mtDNA reference sequence rCRS), H1b, which is common in Western Eurasia, and the rare H33, which is also present in the Near East. Additionally, the reconstructed microbiome of the Shroud reveals a rich tapestry of multiple microbes commonly found on the human epidermis, as well as archaeal communities adapted to high salinity and fungi including molds. These findings are consistent with the preservation conditions experienced by the Shroud over the centuries. The presence of abundant Mediterranean endemic red coral, various cultivated plants (e.g., carrot, wheat, corn, bananas, and peanuts) and domesticated animals (e.g., cattle, pigs, chickens, dogs, and cats) provide a fascinating glimpse into the diverse biological sources of the contaminants that have accumulated on the Turin Shroud over time. Finally, radiocarbon dating of two distinct threads collected from the reliquary is consistent with their use in repair interventions of the Shroud carried out in 1534 and 1694 CE.

In the version of this article initially published, there was an error in the units listed in the Fig. 1b x -axis label, where in the text now reading “Age (Ma),” “Ma” originally appeared as “Ga.” The figure is now updated in the HTML and PDF versions of the article.

Abstract Over geological time, the growth of the ocean floor involves magmatic and tectonic extension 1 at mid-ocean ridges (MORs). Because seismogeodetic monitoring of these submarine plate boundaries remains challenging 2–7 , little is known about how these systems operate on yearly timescales. Here we report the first, to our knowledge, in situ observation of a rifting event at a MOR segment that combines hydroacoustic, direct-path ranging and bottom-pressure measurements, with repeated seafloor mapping. This event started on 26 April 2024 at the axis of the Southeast Indian Ridge (SEIR) near 37° S, two months after instruments had been deployed across the ridge axis and nearby Amsterdam transform fault (TF). The event began as a rapidly migrating swarm of extensional seismicity along the axial valley. It caused 4 m of subsidence of the valley floor and more than a metre of horizontal extension across the valley. We interpret this as the deflation of a sill-like reservoir feeding propagating dykes along the ridge axis. The dykes eventually led to the outpouring of about 160 million m 3 of lava at the seafloor in about 16 days, while inducing both seismic and aseismic slip on valley-bounding normal faults and finally triggering seismic activity on the abutting TFs. Large-scale aseismic slip induced by magmatic processes could therefore be the primary mechanism by which MOR normal faults accrue their displacement, which would account for their well-documented seismic deficit 8,9 .

Arctic sea-ice decline is fundamentally altering the momentum transfer between the atmosphere and ocean, with important implications for the climate system. However, capturing the complexity of air-ice-ocean interactions across varying timescales remains a challenge for climate models. Here, we show that Arctic Ekman pumping is organized into seven distinct physical regimes identified using a probabilistic clustering framework applied to a 26-year state estimate. These regimes reflect different combinations of wind, ice, and geostrophic forcing, alongside a residual component that becomes more prominent during seasonal sea-ice transitions. Spatially, the Beaufort Sea is characterized by frequent transitions and persistent ice-geostrophic coupled regimes, whereas the Nordic and Eurasian marginal seas exhibit greater variability in regime stability over time. This regime framework provides a physically grounded link between atmospheric forcing and surface momentum balance, offering a process-based perspective on how changing ice cover may influence Arctic upper-ocean dynamics.

Abstract Biological dinitrogen (N 2 ) fixation sustains productivity in oligotrophic oceans and is now also thought to contribute substantially to the nitrogen supply in the warming Arctic. Here we demonstrate significant N 2 fixation by particle-associated diazotrophs in subsurface waters of the Barents Sea. Comparing our findings with subtropical studies reveals particle-associated non-cyanobacterial diazotrophs as the primary N 2 fixers in subsurface Arctic waters of the Barents Sea, contrasting with diverse communities in warmer regions. As the Arctic shifts towards oligotrophication, understanding the magnitude and controls of particle-associated N 2 fixation will provide critical insights into future nitrogen supply required to sustain productivity in the rapidly changing Arctic Ocean. However, particle-associated N 2 fixation may be a distinctive feature of the Barents Sea, where in contrast to other Arctic shelves the seasonal and long-term trends in nitrogen dynamics are heterogeneously determined by changes in the external Atlantic Water supply, sea-ice extent, and terrestrial inputs. In this context, the role of particle-associated N 2 fixation across the wider Arctic Ocean will require further investigation.

Observations from satellites and climate-model simulations show that moderate volcanic eruptions and extreme wildfires have humidified the stratosphere since 2005. The aerosol-mediated effects of these eruptions and fires explain about one-third of the observed stratospheric water-vapour trend, a contribution similar to that of surface warming. Moderate eruptions and extreme fires account for about one-third of the upward trend in stratospheric moisture.

Cloud attenuation due to cloud particles can be a critical issue for next-generation sub-terahertz (sub-THz), terahertz (THz), and free-space optical (FSO) satellite communications. Accurate estimation of cloud attenuation under various cloud conditions is essential for the design of satellite communication systems; accordingly, numerous cloud attenuation estimation models have been proposed. The widely used ITU-R model proposed up to 200 GHz is based on liquid water content and does not explicitly consider ice crystals. Previous studies have often assumed water droplets to be dominant, potentially leading to unrealistic cloud attenuation estimates, especially in multilayered cloud systems where ice crystals can exist over a wide temperature range. In addition, approaches based on reanalysis data and numerical weather prediction models rely on parameterized cloud representations and may involve substantial uncertainties. These limitations highlight the need for observationally grounded evaluations that explicitly account for both water droplets and ice crystals. In this study, cloud attenuation was estimated up to wavelengths of approximately 20 [Formula: see text] (corresponding to about 10 THz) using ten cloud microphysical data obtained from cloud particle sensor (CPS) sondes observed in Okinawa, Japan, during the Baiu (East Asia rainy season) in 2016, 2017, and 2025. CPS sondes enable the vertical measurement of the number of cloud particles along the sonde flight path and allow for their rough classification into water droplets and ice crystals, making them particularly well-suited to addressing the aforementioned challenges. Cloud attenuation was estimated based on in situ observational data obtained using CPS sondes. To the best of our knowledge, this study is the first to estimate cloud attenuation for satellite communications using in situ observational data of cloud particles. The results demonstrate that cloud attenuation due to ice crystals becomes dominant, particularly at wavelengths shorter than 1.0 mm, challenging the conventional picture that cloud attenuation is dominated by water droplets. This finding was obtained by explicitly considering the size distribution of ice crystals. A key contribution of this study is the identification of limitations in conventional cloud attenuation models for satellite communications using in situ cloud particle observations. Expanding similar studies globally could lead to the development of more accurate and widely applicable cloud attenuation models.

Mamenchisauridae is a group of long-necked non-neosauropodan eusauropod dinosaurs that were abundant in East Asia during the Middle to Late Jurassic, but their diversity and geographic distribution outside China remain poorly documented. Here we describe Uragasaurus kalasinensis gen. et sp. nov., a new sauropod dinosaur from the Phu Kradung Formation of northeastern Thailand. The new taxon is based on a well-preserved anterior dorsal vertebra exhibiting a distinctive combination of characters, including a unique Y-shaped configuration formed by the intraprezygapophyseal and single intraprezygapophyseal laminae and a camellate internal pneumatic structure within the centrum revealed by computed tomography (CT). Phylogenetic analyses recover the new taxon as an early-diverging member of Mamenchisauridae. This discovery represents the first formally named mamenchisaurid from Thailand and expands the known geographic distribution of the clade in Southeast Asia. The occurrence of this taxon in the Lower part of the Phu Kradung Formation also contributes to understanding faunal succession within the unit, supports an Upper Jurassic age for the lower part of the formation, and improves understanding of sauropod diversity in Southeast Asia during the Jurassic-Cretaceous transition.

Accurate forecasting of severe convective events is vital for meteorologists, as it directly supports their efforts to understand atmospheric risk patterns and enable effective early-warning systems. This paper presents an Integrating Heuristic Knowledge with Attention-based LSTM Networks for Thunderstorm Prediction (HoST) for probabilistic thunderstorm prediction. The proposed framework integrates attention-enhanced recurrent modelling with physically informed heuristic constraints, allowing the model to capture complex nonlinear atmospheric dynamics while maintaining meteorological consistency. The model is evaluated on a real-world observational dataset, where it demonstrates strong predictive capability in capturing spatiotemporal convective patterns. Furthermore, the framework is assessed in a quasi-operational forecasting setting, exhibiting low-latency inference, computational efficiency, and stable predictive performance across multiple forecast lead times (5-60 minutes). To further validate the robustness of the approach, controlled experiments are conducted using synthetically generated atmospheric scenarios that emulate key thermodynamic and kinematic relationships. Results show improved classification stability, enhanced probabilistic calibration, and superior performance compared to Random Forest, SVM, Improved Decision Support, Deep Neural Network, SALAMA, BLSTM-GRU, MetNet, FourCastNet, GraphCast, HRRR, and AROME models. Overall, the findings highlight the effectiveness of integrating heuristic knowledge with data-driven learning, demonstrating the potential of HoST as a physically consistent and operationally viable framework for short-term thunderstorm forecasting.

El Niño is the leading mode of interannual climate variability, driving seasonal predictability worldwide. It has been found that tropical variability, as that in the Atlantic, can impact on ENSO in certain decades, affecting its predictability. Nevertheless, a comprehensive analysis of the role of the Tropical Atlantic in changing ENSO predictability along time has not been assessed so far. This work analyses the Atlantic-Pacific connection and its impact on ENSO prediction using the 20th century reforecast of the ECMWF operational seasonal forecast model, SEAS5-20C, for which changes in ENSO predictive skill over the century have been previously found. Using this reforecast, multidecadal variability of tropical basin interactions appear together with changes in tropical Atlantic and Pacific predictability. It is found how the connection between tropical basins is related to the improvement in ENSO prediction, even in the second year after the initialization (+12 month lead-time), confirming that changes in the background conditions modulate these changes in predictability.

We propose and empirically evaluate a two-stage approximation to a Generalized Multivariate Functional Additive Mixed Model (GMFAMM) for the joint bias correction of five NASA POWER reanalysis variables: minimum and maximum temperature (Tmin, Tmax), relative humidity (RH), solar radiation (Rad), and precipitation occurrence (Pbin). Our primary contribution is the first operational-scale evaluation of such a framework (≈200,000 station–day observations, two orders of magnitude beyond previous studies) together with its deployment in an open-access web application. A systematic grid of more than 200 marginal configurations is evaluated on a strict chronological 70/30 hold-out (training 2016–2022; testing 2023–2025) to identify the optimal marginal specification per variable. Against a correctly specified marginal baseline, station-level linear calibration combined with the marginal GAMM removes the bulk of the systematic bias (RMSE reductions of ≈80%, 82% and 30% for Tmin, Tmax and RH). A shared latent step, using the first principal component of the marginal residual matrix as a scalar proxy for Λ0(t), yields additional but conditional out-of-sample reductions (≈17% Tmax, 10% RH, 9% Rad; negligible for Tmin, with precipitation occurrence retained in the shared representation but its joint gain treated as exploratory); because it requires co-located donor observations, at ungauged locations the deployed pipeline applies the marginal correction only, whose spatial transfer is confirmed by leave-one-station-out cross-validation. The residual cross-correlation structure is consistent with, though not in itself proof of, Clausius–Clapeyron coupling. The trained artefacts are deployed in ColClim, an open-access R Shiny application that queries the NASA POWER API and the Open-Meteo forecast service for any location in Colombia and delivers historical bias-corrected series and short-range (1–16 day) forecasts.

Abstract Whether Archean arc-like volcanism reflects subduction remains debated. We present high-resolution geochemical data from a well-preserved 3.13-3.10 Ga arc-like volcanic succession in Australia’s Pilbara Craton, a rare Archean analog of modern arc volcanism retaining fluid-mobile element concentrations consistent with primary magmatic values. The sequence records three primitive lava series typical of modern arcs: tholeiitic, calc-alkaline, and the oldest stratigraphically extensive genuine boninites. Geochemical modelling shows this melt diversity requires at least two mantle sources with distinct depletion histories. The mantle H 2 O required for fluid-assisted melting to produce these lavas substantially exceeds primitive mantle, approaching the H 2 O-saturated solidus of modern mantle wedges. We infer hydrous melting was triggered by dripduction, the short-lived inclined foundering of hydrated lithosphere without laterally continuous plate boundaries, in an off-plateau setting. Dripduction locally recycled surface water and generated arc-like magmas without self-sustained plate tectonics, possibly promoting mantle-ocean-atmosphere volatile exchange during the Archean.

Abstract The geological origins of iron oxide-apatite (IOA) rocks, important resources for iron and rare-earth elements, are intensely debated. Using triple oxygen isotope data, we here show that magnetite from IOA deposits near Kiruna, northern Sweden, and related igneous rocks contain high concentrations of oxygen derived from evaporitic sulfate. To explain these observations, we propose that the Kiruna IOA assemblage formed in response to massive assimilation of evaporites by silicate magmas. sulfate from the evaporites would have oxidised ferrous iron in these magmas, facilitating the formation of immiscible ferric iron-rich melts and/or magnetite, which then separated from the magmas to form ore deposits. Ferric iron-bearing fluids with low Δ′ 17 O values, exsolved from the silicate magmas or the ore-forming melts, would have crystallised additional magnetite. An inventory study reveals that Proterozoic and Cambrian IOA deposits have lower Δ′ 17 O values than post-Cambrian IOA deposits. This shows that the Δ′ 17 O values of global IOA deposits reflect the changing isotope composition of atmospheric O 2 incorporated by evaporitic sulfate over time, and demonstrates that oxygen released from evaporitic sulfate is a common component in IOA deposits.

Seafloor hydrothermal deposits with extremely high concentrations of gold were recently discovered in the Higashi-Aogashima knoll caldera hydrothermal field, Izu-Ogasawara arc Japan. We report here the discovery of ultra-high concentrations of "invisible gold" (up to 1.9 wt%) in pyrite from the sulfide mounds and a black smoker chimney using a secondary ion mass spectrometry (SIMS). A notable feature of this study is that quantitative gold concentrations were obtained from all analyzed pyrites due to the high sensitivity (7 ppb) and wide measurement range of the SIMS analysis. The concentrations of gold and arsenic in pyrite are higher than those in the whole rock on any hydrothermal sites within the caldera, suggesting that gold and arsenic are concentrated in pyrite. The gold concentrations in pyrite vary greatly depending on the site of the deposit and morphology of pyrite. The extremely high gold concentrations are found from colloform pyrites with high lead and/or copper concentrations in addition to arsenic concentration in pyrite, which might have induced the high gold concentration in pyrite. No gold nanoparticles were observed in high spatial resolution SIMS depth profiles of pyrite, and it is believed that gold and other elements are contained within the pyrite crystal structure.

The paleosol horizons on the lower terrace of Wadi Shuwayhi are the first buried soils from the Holocene Humid Period in Central Oman have been studied; they occur in alluvial sediments (terrace fill) deposited approximately 11.5 to 7 ka, with radiocarbon ages of soil organic matter range from 10,600 to 5300 cal BP (8700-3500 cal BC). The youngest buried soil horizons in profile KS3 show disturbances in soil structure, consistent with Early Bronze cultivation at 4800-4400 cal BP (2800-2500 cal BC). Pedogenic features in the buried A and B horizons of all paleosols show subangular blocky and crumb macro- and microstructure, bioturbation features, and secondary calcification within root channels. In two soils, tabular and lenticular gypsum is particularly pronounced. Although the organic carbon content is low at all sites, soil formation suggests earlier vegetation establishment during the Holocene Humid Period as is also known from other arid areas. Alternating phases of alluvial aggradation and lateral erosion, i.e. stability and instability of the wadi terraces, are reflected in the preserved, albeit relic paleosol horizons. The study describes and classifies the buried soils, place them within a stratigraphic framework, and evaluates their significance as proxies of the HHP as well as early human-environment interactions in Southern Arabia.

In the version of this article initially published, due to a file conversion error, in Fig. 1a, black trace lines for collision boundaries in the Carpathians and Apennines were disconnected from their respective arrow points. The figure is now amended in the HTML and PDF versions of the figure.

Coastal blue-carbon burial is vulnerable to climate change, yet marine hydrodynamic effects remain poorly quantified. Here we estimate hydrodynamic effects on carbon accumulation rate (CAR), by integrating global observations across mangroves, marshes and seagrasses with multiple drivers. Across all ecosystems, hydrodynamics explains 11.8-16.2% of CAR variability, whereas within individual ecosystems it explains 14.5-31.4%, 13.2-13.9% and 14.7-17.7% in mangroves, marshes and seagrasses, respectively. Limited tidal ranges leave low-CAR, inundation-tolerant seagrasses more common, whereas larger tidal ranges support broader intertidal habitats for high-CAR mangroves and marshes. Wave forcing shows contrasting relationships with CAR: positive in mangroves and seagrasses, potentially linked to organic matter inputs, but negative in marshes, likely reflecting lateral export. As sea-level rise accelerates and storms intensify, carbon-release risks may become heterogeneous, with marshes most vulnerable and mangroves and seagrasses more conditional and regionally uncertain. These findings provide a hydrodynamic framework for predicting future carbon dynamics.