2026-05-15T08:05:44Z http://oai-pmh.copernicus.org/oai.php

oai:publications.copernicus.org:wesd140740 2026-05-13 wesd

Fei, Zheni Nishino, Takafumi Vogel, Christopher R. 2026-05-13 Text application/pdf https://doi.org/10.5194/wes-2026-76 eISSN: 2366-7451 eng

oai:publications.copernicus.org:wes136536 2026-05-13 wes

Seifermann, Pascal Schaaf, Jonathan Störtenbecker, Sven Dam, Alexander Dalhoff, Peter This paper presents the development and analysis of a novel drivetrain concept for large-scale wind turbines. The proposed concept builds on a predominantly mechanical transmission, with a small fraction of power transferred by a hydraulic system. The hydraulic power path, an adjustable hydrostatic transmission with a pump and a motor, enables full rotational speed variability while transmitting only a limited portion of the total power. As a result, a higher overall efficiency can be achieved compared to fully hydrostatic drivetrains. Furthermore, it is possible to couple the generator directly to the grid, thus omitting the frequency converter which contributes to system complexity, losses, and failure susceptibility.

A simulation model incorporating component-level loss representations is developed to evaluate different transmission layouts and design variants. It is investigated whether a hydromechanical power-split drivetrain can achieve efficiency and energy yield levels comparable to conventional geared drivetrains while referring to the characteristics of currently available hydraulic components.

The results show that the drivetrain efficiency strongly depends on the transmission layout and the site-specific wind conditions. While lower efficiencies are observed for sites with low mean annual wind speeds, specific design configurations achieve high efficiencies and energy yields comparable to those of a conventional geared reference drivetrain at sites with higher mean annual wind speeds. Overall, this paper extends previous research by minimizing the rated power of the hydraulic power path, estimating efficiencies for different drivetrain configurations, and looking into a mechanical design.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/wes-11-1733-2026 eISSN: 2366-7451 eng

oai:publications.copernicus.org:os137510 2026-05-13 os

Haren, Hans Height variations O(1) m of closely spaced moored oceanographic instrumentation are difficult to measure in the deep sea, requiring high-accuracy pressure sensors preferably on all instruments in a mooring-array. In this paper, an alternative method for relative height determination is presented using 2 m spaced high-resolution temperature sensors moored on multiple 9.5 m-spaced lines in the deep Western Mediterranean Sea. While it was anticipated that height variations between lines could be detected under near-homogeneous conditions via adiabatic lapse rate O(10⁻⁴ °C m⁻¹) by the 3 × 10⁻⁵ °C-noise-level sensors, such was prevented by the impossibility of properly correcting for short-term bias due to electronic drift. Instead, a satisfactory height determination was achieved during a period of relatively strong stratification and large turbulence activity. By band-pass filtering data of the highest-resolved turbulent motions across the strongest temperature gradient, significant height variations were detectable to within ±0.2 m.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/os-22-1501-2026 eISSN: 1812-0792 eng

oai:publications.copernicus.org:os135992 2026-05-13 os

Marez, Charly Bendinger, Arne Dilmahamod, Ahmad Fehmi Mesoscale eddies play a key role in the transport of heat, salt, and momentum in the ocean, yet their statistical characterization at high latitudes has remained elusive due to the coarse resolution of conventional satellite altimetry. Here we present a statistical description of the mesoscale eddies in the Labrador Sea at an unprecedented resolution, using observations from the Surface Water and Ocean Topography (SWOT) mission, significantly extending previous estimates derived from lower-resolution altimetry products. We apply an eddy-detection algorithm directly to the native 2 km SWOT swaths, without gridding or assimilation, and validate the detections against in situ measurements from shipboard current profiler data from one cruise in 2024, as well as against a statistically derived shipboard current-profiler-based eddy census. The comparison demonstrates good agreement in eddy size and intensity, confirming SWOT's ability to resolve high-latitude mesoscale structures previously undetectable or distorted in gridded altimetry. The SWOT-derived eddy census based on two full calendar years reveals a predominance of energetic anticyclones (Irminger Rings) in the basin interior and smaller cyclones along the continental slopes, with clear seasonal variability linked to boundary current instability. These findings provide the first observational benchmark for mesoscale activity in the Labrador Sea and illustrate SWOT’s potential to extend eddy statistics to high-latitude and ice-influenced regions, opening the way for a global assessment of mesoscale variability.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/os-22-1515-2026 eISSN: 1812-0792 eng

oai:publications.copernicus.org:nhess134286 2026-05-13 nhess

Seivane, Helena Schimmel, Martin Diffuse volcanic degassing is a persistent and often underestimated natural hazard, with potential impacts on air quality, ecosystem health, and volcanic risk management. Detecting and monitoring this process is challenging, especially in volcanoes lacking visible fumarolic activity, where the final stage of gas migration is jointly modulated by the shallow subsurface structure and natural pressure forcings. We present a continuous monitoring approach based on Rayleigh wave ellipticity from ambient seismic noise to track pressure-driven gas transport in the uppermost soil layers. Applied to Cumbre Vieja Volcano (La Palma, Canary Islands), the method detects subdaily seismic velocity variations linked to periodic pressure oscillations, consistent with natural forcings such as atmospheric and solid earth tides. In this work, we focus on the terdiurnal cycle, the only subdaily band at La Palma Island that reflects purely atmospheric pressure forcing. Its temporal evolution reveals long-term fluctuations that broadly coincide with reported CO₂ emission trends, despite differences in spatial and temporal resolution between both estimates. In addition, we identify a clear semiannual cycle in the long-term ellipticity response at the terdiurnal frequency. This seasonality coincides with the modulation by solid Earth tides and confirms their role in controlling permeability in the upper vadose zone and in the enhancement of barometric pumping efficiency across all stations analyzed. Prior to the 2021 eruption, the terdiurnal cycle reveals contrasting station responses, with TBT exhibiting the earliest and most sustained increase. Together, these observations point to the usefulness of this approach as a complementary tool in the assessment of diffuse degassing and volcanic unrest. This seismic-noise-based approach offers a cost-effective and resilient strategy for detecting hazardous gas migration, supporting early warning and mitigation efforts in volcanic regions.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/nhess-26-2249-2026 eISSN: 1684-9981 eng

oai:publications.copernicus.org:nhess128861 2026-05-13 nhess

Petrescu, Laura Antonescu, Bogdan Nistor, Sorin Floroiu, Iustin Ene, Dragoş Ghica, Daniela Ionescu, Constantin Anghel, Andrei Datcu, Mihai In August 2024, a devastating storm struck Romania's Black Sea coast, setting new precipitation records and marking an unusual change relative to historical climate observations. To investigate this extraordinary event, we integrated non-conventional sensors (seismic, GNSS, infrasound, and satellite data) with ERA5 meteorological reanalysis to monitor storm dynamics. High-frequency (>30 Hz) seismic signals captured precipitation, while microseismic bands (0.1–1 Hz) reflected wave-induced ground motion. Analysis of infrasound data via unsupervised learning delineated periods of acoustic quiescence from storm-related activity. The temporal evolution of these infrasound states coincided with distinct patterns in seismic ground motion, suggesting a shared origin in the storm's atmospheric dynamics. The infrasound array also detected over 1100 signals in the 0.6–7 Hz band, matching lightning discharges observed by geostationary satellites. GNSS data recorded a buildup of precipitable water vapor that peaked concurrently with intense rainfall, following a multi-day increase that preceded the main storm phase. This study highlights the value of integrating diverse, non-traditional datasets to enhance the resolution and depth of storm analysis. Their combined use offers a more holistic understanding of storm evolution and supports future research on the potential role of multi-sensor observations in improving early-warning systems in vulnerable coastal regions.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/nhess-26-2227-2026 eISSN: 1684-9981 eng

oai:publications.copernicus.org:jm137420 2026-05-13 jm

Olivera, Daniela Elizabeth Zavala, Carlos Quattrocchio, Mirta Elena Soreda, María Eugenia Scasso, Roberto Yang, Renchao This study presents a detailed palynofacies analysis integrated with lacustrine sequence stratigraphy to evaluate the role of climate-driven hydrological balance on basin infill and its impact on the organic matter accumulation in the Jurassic Cañadón Asfalto Formation, Cerro Cóndor depocentre, Extra-Andean Patagonia, Argentina. It provides valuable insights into the changes in the nature and taphonomic history of the organic matter throughout the different stages of a lacustrine system's evolution based on the analysis of 51 outcrop samples from the Cañadón Lahuincó “A” section. Two depositional sequences are recognised. Sequence I documents the evolution from underfilled to balanced-fill/overfilled lake stages. Underfilled conditions are characterised by extreme lake-level variability, while the transition to balanced-fill/overfilled conditions is marked by stacked coarsening-upward successions. Sequence II is bounded by an abrupt accommodation increase and initially records renewed underfilled conditions, followed by the establishment of a fully overfilled lake stage characterised by persistent progradational stacking patterns. The most conspicuous feature of the Cañadón Asfalto Formation's organic matter is the overall dominance of land-derived fraction. The variations between the allochthonous and autochthonous (algae and algal-derived amorphous organic matter) material suggests variable climatic conditions, with the alternation of wetter and drier periods at least during the Sequence I and part of the Sequence II. Four palynofacies types (PT-A to PT-D) were defined recording variations in depositional energy, redox conditions, and sediment–water balance. PT-A and PT-D indicate wetter periods, while PT-B indicates relatively drier intervals. PT-C shows the changes between these two opposite situations. The underfilled stage is characterised by the dominance of reworked terrestrial phytoclasts (indicating high-energy inflow events) and poor sporomorph preservation. Conversely, the balanced-fill stage shows sporomorph-rich palynofacies. In both lake stages, blooms of well-preserved strong fluorescence Botryococcus colonies (chlorophytic algae) are registered during drier periods. The overfilled conditions are characterised by the lack of palynomorphs. Kerogen varies from Type III (PT-A) to mixed Type I/III in algae-rich intervals (PT-B, PTC), confirming hydrological balance as the control on organic matter preservation.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/jm-45-335-2026 eISSN: 2041-4978 eng

oai:publications.copernicus.org:soil133858 2026-05-13 soil

Hu, Yang Viscarra Rossel, Raphael A. Soil carbon sequestration refers to the process of capturing atmospheric carbon through plant photosynthesis and storing it in soil as organic carbon. The primary mechanism for carbon sequestration is the adsorption of organic carbon molecules onto the mineral surfaces of the soil's fine fraction (clay + silt ≤ 20 µm), forming mineral-associated organic carbon (MAOC). Soil has a finite capacity to stabilise and sequester organic carbon, known as carbon saturation capacity, which depends on the proportion of reactive minerals in the soil. The difference between the current MAOC content and the carbon saturation capacity is referred to as the organic carbon saturation deficit (C_def) or sequestration potential. Fourier-transformed (FTIR) mid-infrared (mid-IR) spectroscopy can simultaneously measure soil properties relevant to carbon stabilisation: organic carbon functional groups, clay and iron-oxide mineralogy and particle size. Therefore, we hypothesise that mid-IR spectroscopy can effectively and accurately estimate C_def. Here, we aim to (i) develop spectroscopic models to estimate the MAOC and C_def of 482 Australian topsoil samples, (ii) model MAOC and C_def using mid-IR spectra and an interpretable machine learning algorithm, and (iii) further interpret the MAOC and C_def models using SHapley Additive exPlanations (SHAP). Using frontier line analysis, we fitted a function to the upper envelope of the MAOC vs. clay + silt relationship to derive C_def. We recorded mid-IR spectra of the samples and used the regression trees method CUBIST to model MAOC content and C_def. We interpreted these models by examining the regression trees and using SHAP. The models were unbiased and estimated MAOC content with R² of 0.86 and RMSE of 2.77 (g kg soil⁻¹), and C_def with R² of 0.89 and RMSE of 3.72 (g kg soil⁻¹). Model interpretation showed that C_def estimates relied on negative interactions with absorptions from organic matter functional groups and positive interactions with absorptions from clay minerals. Our results demonstrate that mid-IR spectra can effectively estimate MAOC and soil C_def, providing a rapid, cost-effective method for assessing and monitoring this critical soil function.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/soil-12-619-2026 eISSN: 2199-398X eng

oai:publications.copernicus.org:hess134994 2026-05-13 hess

Heinz, Malve Holzkämper, Annelie Kumar, Rohini Ledain, Sélène Horton, Pascal Schaefli, Bettina Droughts are increasingly threatening agricultural productivity. One potential adaptation is to increase the soil water retention capacity, which can be achieved by increasing soil organic carbon (SOC) through agricultural management. We investigated how increasing SOC affected catchment-scale hydrology including extremes. SOC increases were implemented via adjustments to soil hydraulic parameters (ρ_b, θ_PWP, θ_FC, θ_Sat, K_sat) in a mesoscale hydrologic modeling (mHM) framework, following literature-reported effects. Our analysis focuses on the medium-sized, agriculturally dominated Broye catchment in Western Switzerland and four nested subcatchments, where we evaluated five SOC increase scenarios of varying depth and magnitude. At the catchment scale, increment of SOC resulted in higher soil water content (1.43 %–3.75 %) and slightly higher evapotranspiration (0.15 %–0.38 %), while subsurface runoff was reduced (0.27 %–0.70 % across all scenarios). These values represent overall net changes over 2016–2022; while at shorter timescales, the magnitude and even direction of effects varied seasonally and by subcatchment. Increased water retention meant more soil water was available for evapotranspiration and less for groundwater recharge and streamflow. Consequently, streamflows were slightly reduced, peak flows modestly attenuated while low flow responses depended on catchment characteristics and timing. In warmer and drier subcatchments, low flow frequency increased in some years, whereas in cooler and wetter subcatchments, conditions in spring and early summer produced a beneficial effect, slightly reducing low flow frequency. Overall, our analysis suggests that large-scale increases in SOC can provide hydrological benefits such as enhanced agricultural productivity and reduced peak flows, but may involve trade-offs through reduced groundwater recharge and thus water availability.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/hess-30-2879-2026 eISSN: 1607-7938 eng

oai:publications.copernicus.org:gmd132321 2026-05-13 gmd

Fuenzalida, Juan Kusanovic, Danilo Meza, Joaquín Meneses, Rodrigo Catalán, Patricio A. We present SWEpy, an open-source Python finite volume (FV) software for solving the shallow water equations (SWEs) on unstructured triangular meshes. The framework combines flexibility and high performance through GPU acceleration and a well-balanced, positivity-preserving, higher-order central-upwind (CU) scheme. These features are required for simulation of hydrodynamic phenomena such as tsunami propagation, flooding, and dam-break flows in complex and large geometries.

To reduce numerical diffusion, a phenomenon commonly encountered in FV methods, SWEpy incorporates a second-order WENO reconstruction together with a third-order strong stability-preserving Runge–Kutta time integration scheme. These numerical components are particularly well-suited for far-field tsunami modeling, where minimizing artificial diffusion is essential to accurately preserve wave amplitude, phase, and dispersion over long propagation distances.

The performance, stability, and accuracy of SWEpy are validated using canonical benchmarks, including Synolakis’ conical island and Bryson’s flow over a Gaussian bump. Its capabilities are further demonstrated through large-scale simulations of the 1959 Malpasset Dam failure and the 2010 Maule tsunami, highlighting its effectiveness in realistic scenarios. Overall, these results show that SWEpy framework delivers high-resolution solutions on consumer-grade hardware, providing a user-friendly and computationally efficient platform for both research applications and operational forecasting.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/gmd-19-3953-2026 eISSN: 1991-9603 eng

oai:publications.copernicus.org:gmd132768 2026-05-13 gmd

Reilly, John A. Chapman, Christopher C. Quinn, Courtney Kajtar, Jules B. Barnes, Ashley J. Holbrook, Neil J. We present a new ultra-high resolution

1 / 30

° (∼ 3 km) regional ocean model of the eastern Australian region and evaluate the performance of this model against two

1 / 10

° (∼ 10 km) models as well as a suite of satellite and in situ observations. We evaluate model biases in the context of (i) submesoscale-permitting (∼ 3 km) vs. mesoscale-permitting (∼ 10 km) horizontal resolution and (ii) differences between version 5 and version 6 of the Modular Ocean Model (MOM5 vs. MOM6) to assess the added value in each case and determine the suitability of our higher resolution model for scientific research. There are some consistent biases shared by the two regional MOM6 configurations, and also in the higher resolution configuration that are not seen in the lower resolution models. These biases are further investigated with two sets of sensitivity experiments to understand the effect of submesoscale eddy parameterization and imposed dynamic viscosity at a submesoscale-permitting resolution. The high-resolution simulation has much higher variance compared to the lower resolution simulations across all evaluation metrics, indicating that the greater spectrum of length scales also manifests in more variability in the temporal domain. The two MOM6 regional configurations of differing resolution appear to be more aligned than the regional (MOM6) and global (MOM5)

1 / 10

° configurations in most results, reflecting the substantial changes made to the MOM between version 5 and version 6. Importantly, we also show that higher resolution is not a panacea: in regions where key dynamics are quasi-linear and well-captured captured by coarser grids (e.g., the EAC jet), further refinement may offer limited benefit – and actually degrade the performance if parameterizations are not appropriately tuned.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/gmd-19-3853-2026 eISSN: 1991-9603 eng

oai:publications.copernicus.org:gmd131564 2026-05-13 gmd

Pardo-Álvarez, Álvaro Fleckenstein, Jan H. Koutantou, Kalliopi Brunner, Philip Fully-coupled solvers have proven to be suitable and computationally efficient tools for studying surface water–groundwater (SW-GW) interactions. Most existing fully-coupled codes use the two-dimensional, depth-averaged shallow water equations for surface flows. As a result, three-dimensional (3D) flow dynamics are ignored in the surface domain, including phenomena important for the SW-GW exchange such as turbulence. Computational Fluid Dynamics (CFD) solvers allow to capture 3D information on the surface turbulent flow by solving the full Navier-Stokes equations. Consequently, they are well-suited for the study of the actual exchange flows of water and solutes across the sediment-water interface. Among the available CFD software, the open-source toolbox OpenFOAM provides a flexible modelling framework to implement user-defined, fully-coupled models for the detailed investigation of SW-GW interaction processes. Based on this CFD platform, Lee et al. (2021) developed hyporheicScalarInterFoam, a fully-coupled 3D solver capable of solving the flow and transport processes in both surface and subsurface domains as well as the interactions across their interface. Despite the potential of this new code to tackle SW-GW interactions, its application to real-world hydrogeological scenarios is constrained by limitations in boundary conditions, parameter heterogeneity and key hydrodynamic and transport processes, among others, which hinder the accurate representation of the complex characteristics of natural systems. To overcome this, an updated and extended version of hyporheicScalarInterFoam, called darcyInterTransportFoam, is presented in this paper. The new fully-coupled solver enhances the applicability of the original by introducing novel simulation features. These include internal solver updates, such as the definition of heterogeneous and anisotropic subsurface fields and the simulation of heat transfer in both domains, as well as newly implemented add-ons, including pre- and post-processing utilities and additional boundary conditions. A complete description of all the new features is provided in this paper. Moreover, the utility of darcyInterTransportFoam is demonstrated in a test case, where the SW-GW flow, solute transport and heat transfer processes are simulated in a highly conductive river-aquifer system.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/gmd-19-3923-2026 eISSN: 1991-9603 eng

oai:publications.copernicus.org:gmd127354 2026-05-13 gmd

Pietak, Alexander Huang, Langwen Fusco, Luigi Sprenger, Michael Schemm, Sebastian Hoefler, Torsten Meteorological simulations produce large amounts of data, which can represent a challenge when trying to store, share, and analyze it. As weather and climate models increasingly simulate the atmosphere at higher spatio-temporal resolution, it becomes imperative to compress the data effectively. While compression algorithms exist for weather data stored in a gridded Eulerian frame, there are, to date, no specialized alternatives for data stored in the Lagrangian frame. In this study, we present psit, a system to compress weather data stored in the Lagrangian frame. The system works by mapping the trajectories to a grid structure, performing additional encodings on these, and passing them to either the JPEG 2000 image compression algorithm or SZ3. The specialty of the algorithm is the mapping phase and the following encodings, which generate the grids in a way that allows the aforementioned compression algorithms to perform well. To gauge the performance of psit, we test a variety of metrics. We demonstrate that in the majority of cases, equivalent or superior compression performance is attained through the utilization of psit as opposed to naive compression with ZFP or SZ3. We also compare compression with measurement inaccuracies. Here, we show that the density of 168 hour long trajectories compressed with a ratio in the range of 30 to 40 behaves similarly to trajectories calculated from uncompressed wind fields with additional random perturbations with magnitude of 0.1 m s⁻¹ in the horizontal and around

6 \times 10^{- 3}

Pa s⁻¹ in the vertical component. Additionally, we conduct two case studies in which we discuss the impact of compression on the study of warm conveyor belts associated with extratropical cyclones and the impact of compression on the radioactive plume prediction of the Fukushima incident in 2011.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/gmd-19-3893-2026 eISSN: 1991-9603 eng

oai:publications.copernicus.org:essdd141086 2026-05-13 essdd

Cui, Guangxi Yuen, Ka-Veng Chen, Ying Liu, Zhiqiang Yang, Dingqi Liu, Guangliang Cai, Zhongya 2026-05-13 Text application/pdf https://doi.org/10.5194/essd-2026-341 eISSN: 1866-3516 eng

oai:publications.copernicus.org:essdd139884 2026-05-13 essdd

Solgaard, Anne Kusk, Anders Merryman Boncori, John Peter Dall, Jørgen Ahlstrøm, Andreas P. Andersen, Signe B. Citterio, Michele How, Penelope Karlsson, Nanna B. Kjeldsen, Kristian K. Larsen, Signe H. Lund, Mads C. Løkkegaard, Anja Lüthi, Martin P. Mejia, Jessica Mankoff, Kenneth D. As, Dirk Sugiyama, Shin Fausto, Robert S. https://doi.org/10.22008/FK2/K70OPK; Solgaard and Kusk (2026)), providing a continuous time series of Greenland Ice Sheet velocity mosaics from January 2016 to the present. The product is derived from Sentinel-1 synthetic aperture radar (SAR) data, gridded at 200 m spatial resolution and updated every 12 days using data spanning two consecutive Sentinel-1 repeat cycles (24 days). Data are typically released within 10 days of the final acquisition and include all valid 6- and 12-day image pairs within the 24-day window.

This update includes several important improvements to the processing chain. The spatial resolution has been refined from 500 m to 200 m, justified by the implementation of an adaptive correlation template size approach for offset tracking, improving velocity retrievals and enhancing delineation of narrow outlet glaciers. We further implement a new mosaicking strategy, which reduces noise associated with ionospheric disturbances. Additional improvements include enhanced error handling and outlier rejection. The full processing workflow is described, including data selection, mosaicking, uncertainty estimation, and filtering procedures.

Validation against in-situ GNSS measurements over the full time series shows that the standard deviation of the differences between satellite- and GNSS-derived velocities (with corresponding bias) is 22 m/yr (-0.3 m/yr) and 38 m/yr (-0.4 m/yr) for the easting and northing components, respectively. These values fall within expected ranges, although a substantial fraction of the discrepancy likely reflects uncertainty in the GNSS measurements. This interpretation is supported by validation over stable terrain, where substantially lower values are obtained: 9 m/yr (0.1 m/yr) and 15 m/yr (-0.1 m/yr) for the easting and northing components, respectively. Compared to the previous product version, uncertainties are higher due to a prolonged period when only one Sentinel-1 satellite was operational, resulting in increased noise and reduced temporal sampling. We quantify the impact of these conditions on spatial coverage.

Overall, coverage is highest during winter, when radar coherence is strong and acquisitions are most comprehensive, whereas summer coverage is reduced due to surface melt. Despite these seasonal and mission-related constraints, the PROMICE ice velocity product provides consistent temporal sampling and broad spatial coverage, supporting investigations of ice-sheet-wide and glacier-specific dynamics and ice discharge on seasonal to multi-year timescales.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/essd-2026-221 eISSN: 1866-3516 eng

oai:publications.copernicus.org:essdd138438 2026-05-13 essdd

Nazir, Muhammad Junaid Yu, Longfei Zhang, Yunjie Zou, Jing Yuan, Wenping Wei, Jing 2O) is not only one of the main potent greenhouse gases, but also currently the dominant ozone-depleting substance. The quantification of N₂O emissions from aquatic ecosystems, despite their global importance, is hindered by fragmented observations, inconsistent data reporting, and pronounced spatiotemporal variability. In this study, to improve accessibility, we introduce the Global Aquatic N₂O Emission Database (GANED; https://doi.org/10.6073/pasta/4a086e49a4f308679b951293b380e7b9, Nazir et al., 2026), a consolidated dataset comprising 5130 N₂O concentration records and 7386 N₂O flux measurements from 3002 sites across diverse aquatic systems, including rivers, streams, lakes, reservoirs, ponds, estuaries, coastal waters, and open seas. The dataset integrates information on aquatic N₂O emission from 426 peer-reviewed publications across 8 continents, covering the period 1980–2023. While the number of observations has increased substantially since 2000, spatial coverage remains uneven, with significant gaps across Africa and parts of high-latitude regions, including Antarctica and South America. Our dataset revealed a highly skewed distribution of N₂O concentration and flux across aquatic ecosystems, with rivers and streams exhibiting the most significant variability and functioning as emission hotspots. Lakes and estuaries showed moderate variability and emission levels, whereas seas and coastal waters were characterized by consistently lower values. Pearson correlation coefficient revealed a strong positive relationship of N₂O fluxes with ammonium (NH₄⁺; R = 0.943, p < 0.001), nitrate (NO₃^-; R = 0.691, p < 0.001), and nitrite (NO₂^-; R = 0.807, p < 0.001). Significant negative correlations were found with dissolved oxygen (DO; R = -0.205, p < 0.05), dissolved organic carbon (DOC; R = -0.977, p < 0.05), and salinity (R = -0.636, p = 0.005), while non-significant associations were observed for water temperature, total nitrogen (TN), and total phosphorus (TP). The GANED dataset facilitates improved quantification of global aquatic N₂O inventories by providing comprehensive N₂O concentrations and fluxes in water bodies, as well as metadata describing sampling location, aquatic system type, and associated environmental parameters. The magnitude and patterns of N₂O emissions from water bodies provided by the GANED database are essential in defining how these aquatic ecosystems shape our climate, refining emission estimates, identifying drivers, and guiding mitigation strategies.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/essd-2026-109 eISSN: 1866-3516 eng

oai:publications.copernicus.org:essd134923 2026-05-13 essd

Friedlingstein, Pierre O'Sullivan, Michael Jones, Matthew W. Andrew, Robbie M. Bakker, Dorothee C. E. Hauck, Judith Landschützer, Peter Quéré, Corinne Li, Hongmei Luijkx, Ingrid T. Peters, Glen P. Peters, Wouter Pongratz, Julia Schwingshackl, Clemens Sitch, Stephen Canadell, Josep G. Ciais, Philippe Aas, Kjetil Alin, Simone R. Anthoni, Peter Barbero, Leticia Bates, Nicholas R. Bellouin, Nicolas Benoit-Cattin, Alice Berghoff, Carla F. Bernardello, Raffaele Bopp, Laurent Brasika, Ida Bagus Mandhara Chamberlain, Matthew A. Chandra, Naveen Chevallier, Frédéric Chini, Louise P. Collier, Nathan O. Colligan, Thomas H. Cronin, Margot Djeutchouang, Laique M. Dou, Xinyu Enright, Matt P. Enyo, Kazutaka Erb, Michael Evans, Wiley Feely, Richard A. Feng, Liang Ford, Daniel J. Foster, Adrianna Fransner, Filippa Gasser, Thomas Gehlen, Marion Gkritzalis, Thanos Goncalves De Souza, Jefferson Grassi, Giacomo Gregor, Luke Gruber, Nicolas Guenet, Bertrand Gürses, Özgür Harrington, Kirsty Harris, Ian Heinke, Jens Hurtt, George C. Iida, Yosuke Ilyina, Tatiana Ito, Akihiko Jacobson, Andrew R. Jain, Atul K. Jarníková, Tereza Jersild, Annika Jiang, Fei Jones, Steve D. Kato, Etsushi Keeling, Ralph F. Klein Goldewijk, Kees Knauer, Jürgen Kong, Yawen Korsbakken, Jan Ivar Koven, Charles Kunimitsu, Taro Lan, Xin Liu, Junjie Liu, Zhiqiang Liu, Zhu Monaco, Claire Ma, Lei Marland, Gregg McGuire, Patrick C. McKinley, Galen A. Melton, Joe R. Monacci, Natalie Monier, Erwan Morgan, Eric J. Munro, David R. Müller, Jens D. Nakaoka, Shin-Ichiro Nayagam, Lorna R. Niwa, Yosuke Nutzel, Tobias Olsen, Are Omar, Abdirahman M. Pan, Naiqing Pandey, Sudhanshu Pierrot, Denis Qin, Zhangcai Regnier, Pierre Rehder, Gregor Resplandy, Laure Roobaert, Alizée Rosan, Thais M. Rödenbeck, Christian Schwinger, Jörg Skjelvan, Ingunn Smallman, T. Luke Spada, Victoria Sreeush, Mohanan G. Sun, Qing Sutton, Adrienne J. Sweeney, Colm Swingedouw, Didier Séférian, Roland Takao, Shintaro Tatebe, Hiroaki Tian, Hanqin Tian, Xiangjun Tilbrook, Bronte Tsujino, Hiroyuki Tubiello, Francesco Ooijen, Erik Werf, Guido R. Velde, Sebastiaan J. Walker, Anthony P. Wanninkhof, Rik Yang, Xiaojuan Yuan, Wenping Yue, Xu Zeng, Jiye Accurate assessment of anthropogenic carbon dioxide (CO₂) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesise datasets and methodologies to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO₂ emissions (E_FOS) are based on energy and cement production data. Emissions from land-use change (E_LUC) are estimated by bookkeeping models based on land-use data. The global atmospheric CO₂ growth rate (G_ATM) is computed from changes in concentration measured at surface stations. The global net uptake of CO₂ by the ocean (S_OCEAN) is estimated with global ocean biogeochemistry models and observation-based fCO₂-products. The global net uptake of CO₂ by the land (S_LAND) is estimated with dynamic global vegetation models. Additional lines of evidence are provided by atmospheric inversions, atmospheric oxygen measurements, ocean interior observation-based estimates, and Earth System Models. This year, we introduced corrections on the E_LUC, S_OCEAN and S_LAND estimates. The sum of all sources and sinks results in the carbon budget imbalance (B_IM), a measure of imperfect data and incomplete understanding of the contemporary carbon cycle. All uncertainties are reported as ± 1σ.

For the year 2024, E_FOS increased by 1.1 % relative to 2023, with fossil emissions at 10.3 ± 0.5 GtC yr⁻¹ (including the cement carbonation sink, 0.2 GtC yr⁻¹), E_LUC was 1.3 ± 0.7 GtC yr⁻¹, for total anthropogenic CO₂ emissions of 11.6 ± 0.9 GtC yr⁻¹ (42.4 ± 3.2 GtCO₂ yr⁻¹). Also, for 2024, G_ATM was 7.9 ± 0.2 GtC yr⁻¹ (3.73 ± 0.1 ppm yr⁻¹), 2.2 GtC above the 2023 growth rate. S_OCEAN was 3.4 ± 0.4 GtC yr⁻¹ and S_LAND was 1.9 ± 1.1 GtC yr⁻¹, leaving a large negative B_IM (−1.7 GtC yr⁻¹), suggesting that the total sink or G_ATM is strongly overestimated in 2024. The global atmospheric CO₂ concentration averaged over 2024 reached 422.8 ± 0.1 ppm. Preliminary data for 2025 suggest an increase in E_FOS relative to 2024 of +1.0 % (0.2 % to 1.7 %) globally, and atmospheric CO₂ concentration increasing by 2.1 ppm reaching 425.6 ppm, 53 % above the pre-industrial level (around 278 ppm in 1750). Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2024, with a near-zero overall budget imbalance, although discrepancies of up to around 1 GtC yr⁻¹ persist for the representation of annual to decadal variability in CO₂ fluxes. Comparison of estimates from multiple approaches and observations shows: (1) a persistent large uncertainty in the estimate of land-use change emissions, (2) a low agreement between the different methods on the magnitude of the land CO₂ flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the mean ocean sink.

This living data update documents changes in methods and datasets applied to this most-recent global carbon budget as well as evolving community understanding of the global carbon cycle. The data presented in this work are available at https://doi.org/10.18160/GCP-2025 (Friedlingstein et al., 2025c).

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/essd-18-3211-2026 eISSN: 1866-3516 eng

oai:publications.copernicus.org:essd130142 2026-05-13 essd

Ferreri, Andrea Pio Romeo, Annalisa Giannuzzi, Rossella Ninivaggi, Teresa Filippucci, Marilena Cecere, Gianpaolo Falco, Luigi Michele, Maddalena Selvaggi, Giulio Tallarico, Andrea The Gargano Promontory (hereafter GP) has attracted the attention of seismologists in recent years for its peculiarities regarding the high rate of low-magnitude seismicity and focal depths in the lower crust. These peculiarities have been highlighted thanks to the new data provided by the OTRIONS seismic network (hereafter OT), installed in 2013 in the GP area, consisting of 15 short-period seismometers, thanks to a fruitful collaboration between UniBa (University of Bari Aldo Moro) and INGV (Istituto Nazionale di Geofisica e Vulcanologia). The first available seismic catalog referred to the first 7 years of the network operation (2013–2018) and suffered from some technological problems of the acquisition system. Thanks to improvements in the data transmission system, these problems were overcome in 2019 and now the OT network data are available in real time. In order to include the most recent seismicity and to cover the temporal gaps existing in the previous catalog, we thoroughly reviewed the 24 h seismic recordings, collected over the decade after the installation, by employing an automatic detect and picking software (CASP, Complete Automatic Seismic Processor). More than 7100 seismic events were initially identified. Through careful manual review, approximately 60 % were confirmed as local earthquakes, and the others were recognized as quarry blasts or false/poorly-located events. Manual review significantly improved the quality of P- and S-phase picking, and consequently led to more accurate earthquake locations, using both linearized and nonlinear algorithms. The manual review resulted in two catalogs, both released on Mendeley Data (Ferreri et al., 2026) (https://doi.org/10.17632/nhfvx7ysxw.6). This study highlights the value of automatic analysis for compiling a seismic catalog, suggesting that the manual review is still necessary. The quality of the catalogs was assessed in detail using statistical parameters and a new formula for the location quality. The completeness magnitude of the new catalogs is as low as 0.82. The noise affecting the network was also evaluated. This study confirms the importance of the OT local network for seismic hazard analysis and provides a useful dataset for seismotectonic and geophysical studies in a long under-monitored region.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/essd-18-3177-2026 eISSN: 1866-3516 eng

oai:publications.copernicus.org:asr127303 2026-05-13 asr

Egaña, Joseba Arrillaga, Jon Ander Gaztelumendi, Santiago We analyze a severe supercell that affected Vitoria-Gasteiz (Basque Country, northern Spain) on 6 July 2023, producing 4–5 cm hail and rainfall rates close to 30 mm h⁻¹. The main objective of this work is to improve the forecasting and early-warning capabilities for similar high-impact storms in the Basque Country. This region lies on the northern edge of one of the most active supercell areas of the Iberian Peninsula, but remains relatively understudied. The synoptic and convective environment is examined using GFS analyses and the 1 km operational WRF configuration of Euskalmet, while the storm evolution and surface impacts are characterized through radar, rain gauge and disdrometer data. Environmental parameters were substantially above the median of Spanish very-large-hail supercells, with surface-based CAPE near 2000 J kg⁻¹, 0–6 km bulk shear of 20–25 m s⁻¹ and 0–3 km storm-relative helicity slightly above 200 m² s⁻². The storm originated from a splitting cell and rapidly intensified as a right-moving supercell, reaching cloud-top heights of 14–15 km and reflectivity values of 60–65 dBZ. This case also shows that convective initiation and storm splitting west of Basque Country must be monitored, as right-moving cells from these areas can affect the Basque Country when the vertical wind profile shows cyclonic curvature.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/asr-22-165-2026 eISSN: 1992-0636 eng

oai:publications.copernicus.org:amt138596 2026-05-13 amt

Schneider, Wolfgang Ground-based comparison of satellite atmospheric products is essential for ensuring data quality and algorithm performance. We present a comparison approach for Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) cloud fraction products using a multi-spectral ground station (DG2MCM-15) located in Kempten, Bavaria, Germany. The ground observatory combines calibration-informed measurement protocols with low-cost commercial sensors, creating a citizen science comparison capability.

Our comparison dataset comprises 276 temporally matched observations between Sentinel-5P overpasses and ground measurements over a four-week period (11 January–8 February 2026). Ground-based cloud detection using an MLX90614 infrared pyrometer yields a Pearson correlation of R=0.879 (N=27 after quality filtering) with Sentinel-5P cloud fraction retrievals. However, this correlation is driven substantially by two high-cloud-fraction observations; the effective degrees of freedom are lower than N would suggest, and the method is better characterised as a three-state classifier (clear/partly cloudy/overcast) than as a continuous cloud fraction retrieval. The root mean square error of 29.1 % cloud fraction reflects a systematic positive bias from spatial scale mismatch between the ground sensor field of view and satellite pixel dimensions. The method reliably distinguishes between clear, partially cloudy, and overcast conditions, though the derived cloud fraction values exhibit clustering due to the temperature-ratio approach used. Exploratory comparison with TROPOMI aerosol index products yielded negligible correlation due to the absence of UV spectral coverage in the ground sensor, identifying a clear instrumentation requirement for future aerosol validation work.

Temporal matching between satellite overpasses and ground observations achieved a mean time difference of 2.7 min, with 95 % of matches within 8 min of satellite observation time. Spatial co-location analysis confirms all comparison points fall within the nominal TROPOMI pixel footprint (3.5 km ×5.5 km at nadir), though the spatial scale mismatch between the ground sensor field of view and satellite pixel dimensions remains the primary source of comparison uncertainty.

Our results demonstrate that low-cost infrared sensors, when operated with calibration-informed measurement protocols, can provide scientifically useful satellite cloud product screening data, reliably distinguishing between clear, partially cloudy, and overcast conditions. The quasi-discrete nature of the derived cloud fraction highlights the need for improved cloud detection algorithms in future work. This approach offers a scalable pathway for expanding ground-based validation networks in regions lacking dedicated atmospheric monitoring infrastructure.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/amt-19-3137-2026 eISSN: 1867-8548 eng

oai:publications.copernicus.org:amt137713 2026-05-13 amt

García, Rosa D. Barreto, África Cachorro, Victoria E. González-Sicilia, Pablo Léon-Luis, Sergio Álvarez-Hernández, Ayoze Bustos, Juan José Ramos, Ramón Almansa, Fernando Álvarez-Losada, Óscar González, Yenny Rivas, Pedro Pablo Torres, Carlos Javier Extreme wildfires represent a highly variable source of atmospheric aerosols with potentially strong impacts on surface solar radiation. In August 2023, an exceptional wildfire on Tenerife (Canary Islands, Spain) reached the neighbourhoods of the Izaña Observatory (IZO, 2400 m a.s.l.). This near-source configuration enabled a rare observational characterisation of the spectral radiative effects of biomass-burning aerosols. During the most intense phases of the event (17–18 August), aerosol optical depth (AOD) at 500 nm reached extreme values of 3.63 and 2.25, respectively, with Ångström Exponent (AE) above 2, indicating a strong dominance of fine-mode smoke particles. Spectral measurements of global-horizontal, direct-normal and diffuse-horizontal solar irradiance (300–1100 nm) show a pronounced attenuation of direct and global irradiances, particularly in the visible range, together with a strong enhancement of diffuse radiation. Relative to clean-sky conditions, daily global irradiance decreased by 21 %–27 %, while direct-normal irradiance was reduced by 72 %–99 %. Spectral aerosol radiative forcing and radiative forcing efficiency at the surface were quantified using radiative transfer simulations under pristine atmospheric conditions as a reference. The integrated spectral radiative forcing (300–1100 nm) for global irradiance reached −395 and −299 W m⁻² on 17 and 18 August, respectively, indicating strong surface cooling dominated by scattering processes. Maximum forcing and efficiency occurred in the visible spectral range, consistent with the optical properties of freshly emitted smoke aerosols. At the same time, increases in the amount of present particles, equivalent black carbon (eBC) and greenhouse gases (CO₂, CH₄ and CO) confirm the direct influence of the wildfire plume on atmospheric composition at IZO. These observations provide one of the few detailed spectral assessments of surface radiative forcing by extreme biomass-burning aerosols at a high-altitude site and highlight the need to accurately represent fine-mode smoke aerosols in radiative transfer and climate models.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/amt-19-3151-2026 eISSN: 1867-8548 eng

oai:publications.copernicus.org:acp135891 2026-05-13 acp

Nibert, Pauline Wu, Yi Joly, Muriel Amato, Pierre Cristofanelli, Paolo Calzolari, Francescopiero Piro, Jean-Luc Putero, Davide Montaguti, Simonetta Renzi, Laura Vogel, Franziska Rapuano, Marco Brigante, Marcello Verhaege, Christophe Baray, Jean-Luc Deguillaume, Laurent Marinoni, Angela Zanatta, Marco Bianco, Angelica In this article, we present the results of the chemical and microbiological characterization of clouds water collected at Monte Cimone (CMN) in Italy at 2165 m a.s.l. during the MC3 (Molecular Composition of Clouds at mt. Cimone) campaign, which took place in October 2024. Twenty-six cloud samples are analyzed. Chemical analyses, including ions, oxidants, trace metals, and microbiological analyses with cell counting, are performed. The chemical characterization and back-trajectories analysis reveal that Mt. Cimone is a site under the influence of marine air masses, coming mainly from southern Europe and from the Mediterranean region. During the measurement campaign, 3 sampling periods are identified: period (1) 7–10 October, with air masses mainly originating from Spain and Atlantic Ocean with a majority of Cl⁻ and Na⁺ that are characteristics of marine origin; period (2) 16–18 October with air masses originating from North of Africa, impacted by a Saharan dust event with a high concentration in Ca²⁺; period (3) 22–23 October marked by air masses originated from southern Italy under polluted influence with a high concentration in NO

_{3}^{-}

. Across the campaign, DOC ranged from 1.6 to 4.3 mgC L⁻¹, while H₂O₂ reached its maximum during period 3 (71.8±35.4 µmol L⁻¹), highlighting enhanced oxidant levels under polluted conditions. This study paves the way to further scientific campaigns intended to better comprehend cloud water composition at Mt. Cimone.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/acp-26-6489-2026 eISSN: 1680-7324 eng

oai:publications.copernicus.org:acp136072 2026-05-13 acp

Wang, Wenfang Tian, Pengfei Zeng, Shuhua Zhang, Yifei Yu, Zeren Cui, Chen Wu, Yunfei Chen, Min Zhang, Lei The spectral dependence of aerosol absorption, characterized by the absorption Ångström exponent (AAE), strongly influences radiative effects, yet the relative importance of controlling factors remains poorly quantified. We integrate multisource observations with an interpretable machine-learning framework (Shapley Additive Explanations, SHAP) to disentangle the roles of chemical composition and particle size in predicting AAE and to evaluate radiative impacts. Field observation in Beijing reveal that near-surface AAE is predominantly influenced by higher fine mineral dust and water-soluble inorganic ions fractions. Multi-year columnar data identify dust loading as the dominant predictor, followed by carbonaceous aerosols. The fine-mode radius accounts for 29 % of size parameters cumulative importance and ranks closely with black carbon. SHAP diagnostics highlight that columnar AAE contributes to radiative forcing at the top of the atmosphere (TOA) comparably to single scattering albedo (SSA), while its impact is clearly weaker at the bottom of the atmosphere and in the atmosphere. These findings help clarify AAE determinants and reduce uncertainties in aerosol radiative effect assessments.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/acp-26-6471-2026 eISSN: 1680-7324 eng

oai:publications.copernicus.org:acp130700 2026-05-13 acp

Hildebrandt, Katarina Grubbe Castino, Federica Meijer, Vincent Yin, Feijia Contrail cirrus is a major contributor to aviation's radiative forcing. Avoiding persistent contrail formation has been suggested as a measure to reduce the climate impact of aviation, requiring accurate forecasts of ice supersaturated conditions, where the relative humidity over ice (RHi) exceeds 100 %. Numerical weather prediction models and reanalysis products often underestimate or do not account for ice supersaturation. This study evaluates ice supersaturated regions (ISSRs) in the ECMWF ERA5 reanalysis dataset using In-service Aircraft for a Global Observing System (IAGOS) measurements over tropical and extratropical regions in the upper troposphere and lower stratosphere from 2011 to 2022. It considers seasonal and vertical differences, and how cloudy and clear-sky conditions affect ERA5’s ability to predict ISSRs. ERA5 underestimates ISSR occurrence due to a dry bias in RHi; the equitable threat score (ETS) is 0.2–0.4, indicating a weak to mediocre skill. Lowering the ERA5 RHi threshold improves ISSR prediction, with the largest improvements for RHi between 85 % and 95 %, although the optimal threshold varies with distance to the tropopause, region and season. Clear-sky conditions result in an ETS of 0.05–0.18, while the ETS is mostly below 0.1 in cloudy conditions, indicating an almost random relationship. In clear-sky conditions, lowering the threshold to 85 % increases the ETS by approximately 0.1. In cloudy conditions, lowering the threshold shows little benefit because increases in correctly predicted ISSRs are offset by increases in false positives. These findings improve our understanding of ISSR variability and has implications for accurate assessment of persistent contrail formation.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/acp-26-6449-2026 eISSN: 1680-7324 eng

oai:publications.copernicus.org:egusphere140981 2026-05-13 egusphere

Wickander, Niklas Jan Dörsch, Peter Aims: Ethiopian soils are highly weathered and in urgent need of remediation. Increasing the soil carbon (C) pool by perennials potentially remediates soil degradation while sequestering atmospheric CO₂. The soil microbial loop is thought to play an important role in soil C sequestration as it contributes significantly to the stabilization of plant litter C. The amount of stabilized litter C has been hypothesized to depend on microbial carbon use efficiency (mCUE), which is sensitive to soil nutrients and plant inputs. Here, we investigate the effect of two perennial forage crops on mCUE in four weathered Ethiopian soils.

Methods: We cultivated the grass Urochloa cv. Cayman as single stand and in mixture with the legume Desmodium intortum in a fully factorial greenhouse experiment with four distinct farmers’ soils from the Ethiopian Rift Valley (Amhara and Sidama). Microbial CUE was assessed after 104 days of plant growth using ¹⁸O-H₂O incorporation.

Results: Microbial CUE varied between the four soils, with Amhara soils showing lower mCUE than Sidama soils. Overall, mCUE was little affected by plant growth but increased significantly with plant dry weight (DW) in one of the two Sidama soils. Mass specific growth rates remained small in Amhara soils, indicating that factors other than plant C input inhibited microbial growth. Plant composition had no effect in Amhara soils while the Urochloa × Desmodium mixture tended to have lower mCUE in Sidama soils.

Conclusions: Perennials may improve mCUE in weathered soils, but this stimulation strongly depends on soil nutrient availability and suggests that there are critical nitrogen (N) and phosphorous (P) thresholds below under which mCUE does not respond to growing plants. This implies that highly degraded soils must be ameliorated before using perennials to stimulate nutrient cycling and restore soil health.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2488 eISSN: eng

oai:publications.copernicus.org:egusphere141013 2026-05-13 egusphere

Whitwell, Chris A. Jones, Nicole L. Ivey, Greg N. Rayson, Matthew D. 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2498 eISSN: eng

oai:publications.copernicus.org:egusphere141030 2026-05-13 egusphere

Wang, Jinbo Zhang, Kunfeng Illman, Walter Chen, Shuai Liu, Mingzhu 5 grid nodes, PHYGNET achieved an acceleration (up to 3524-fold) without numerical crashes. Furthermore, its escalating speedup ratio establishes a "small-sample training, ultra-large-scale inference" paradigm that effectively offsets initial data generation costs. Overall, PHYGNET provides an efficient and physically consistent framework for accelerating Monod-type microbial reactive transport simulations, offering a practical pathway for large-scale environmental applications.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2509 eISSN: eng

oai:publications.copernicus.org:egusphere141039 2026-05-13 egusphere

Huang, Minde Guo, Fen Gao, Xueqin Ouyang, Xiaoguang Zhang, Yuan 210Pb profiles, source composition using isotope end-member mixing, and stability from turnover metrics. Our results showed a coordinated triad response to urbanization. Carbon stocks and burial declined, sources shifted away from mangrove detritus toward planktonic and algal inputs, and turnover accelerated, lowering stability. Responses were habitat dependent and nonlinear. Natural mangroves in low urbanization settings maintained the highest sequestration with mangrove-dominated inputs and slower turnover. Restored stands and tidal flats showed steeper stock losses, stronger source substitution, and faster cycling under higher urban pressure. We introduced a triad framework that treats stocks, sources, and stability as coupled state variables along the urbanization gradient and identified two reproducible system states: carbon anchors in low urbanization natural mangroves and instability fronts in restored stands and tidal flats. Shifts in sources and stability precede stock losses, providing clear early warnings of urban impact. A simple diagnostic that combines connectivity and accretion with source composition and a composite stability index guides anchor protection and stability-first restoration. These results link urban growth to blue-carbon performance and define actionable thresholds for sustaining coastal carbon.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2512 eISSN: eng

oai:publications.copernicus.org:egusphere141150 2026-05-13 egusphere

Luo, Zeng Wang, Hansheng Yu, Xiaoli Zhang, Zhongbao Song, Zhifen Yang, Jing Chen, Wanfeng Su, Qiangda Lu, Yang Hua, Shun 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2580 eISSN: eng

oai:publications.copernicus.org:egusphere141082 2026-05-13 egusphere

Kolesnichenko, Yuri Ya. Vorobyev, Sergey N. Nikitkin, Viktor A. Dudarev, Oleg V. Chernykh, Denis V. Spivak, Eduard A. Kurilenko, Arkadiy V. Kholodov, Vladimir A. Semiletov, Igor P. Pokrovsky, Oleg S. 2 measurements, floating chamber flux determinations, and analyses of major and trace elements including colloidal size fractionation. CO₂ concentrations exhibited pronounced short-distance variability and weak northward decrease along the main stem. Diffusive CO₂ fluxes (0.1–1.3 g C m⁻² d⁻¹) were comparable to values reported for other large Siberian rivers, confirming the Lena as a persistent but moderate atmospheric CO₂ source during the open-water season. In contrast, CH₄ concentrations were low and spatially uniform, contributing <0.5 % to total carbon emissions. Notably, bulk DOC and DIC concentrations remained remarkably stable along the transect and were consistent with long-term monitoring records and previous expeditions, indicating strong buffering of dissolved carbon pools despite dynamic CO₂ evasion.

Major and trace elements segregated into two geochemical groups. Highly mobile major ions, Si, and selected oxyanion-forming trace elements were predominantly present in truly dissolved form (0–20 % colloidal fraction) and reflected groundwater connectivity and water–rock interaction. In contrast, lithogenic low-solubility elements – including trivalent and tetravalent hydrolysates – were strongly associated with Fe–Al–organic colloids (>70 %), indicating surface and suprapermafrost mobilization pathways. Multivariate statistics confirmed this dual organization of solute transport. These findings reveal a functional decoupling between structurally buffered dissolved carbon pools and dynamically regulated CO₂ exchange, a pattern likely characteristic of large Arctic rivers. Under ongoing warming, shifts in hydrological connectivity, discharge regime, and permafrost thaw may alter this balance, with implications for pan-Arctic carbon and element export to the Arctic Ocean.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2540 eISSN: eng

oai:publications.copernicus.org:egusphere141123 2026-05-13 egusphere

Giordano, Fabio Ličer, Matjaž Querin, Stefano Salon, Stefano Vodopivec, Martin °C above the 20-year average and 1.2^°C above the previous maximum recorded since 2002. Observations and modelling indicate that the BMHW was preconditioned by a prolonged drought starting in 2022 and continuing into 2023. This resulted in elevated surface salinity and weakened stratification, allowing unusually deep mixing that extended to the seafloor. Although 2023 was warm, heat was distributed over a thicker water column than usual, limiting sea surface warming but causing extreme temperatures at depth. The event persisted into autumn due to freshwater inflow, which re-established stratification and trapped the heat below. As surface temperatures remained moderate, the BMHW was undetectable by satellites or surface measurements. Only bottom sensors and models revealed the stress in deeper layers. Such events may therefore remain unnoticed while exerting extreme stress on the marine ecosystem. Our findings highlight reduced precipitation and deep mixing as overlooked drivers of subsurface marine heatwaves, which may become more frequent in similar shallow and stratified areas subject to increasingly frequent droughts driven by climate change.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2567 eISSN: eng

oai:publications.copernicus.org:egusphere141092 2026-05-13 egusphere

Thomas, Rhidian Huw Compo, Gilbert P. George, Steve Hegerl, Gabriele C. Schurer, Andrew Shepherd, Theodore G. Slivinski, Laura C. Thompson, Vikki Hawkins, Ed 2 levels. By assimilating the same pressure observations, the reanalysis experiments produce the same weather patterns, and so we translate the weather of 1903 into a warmer context. We focus on changes in the everyday weather of four regions with a high density of historical pressure observations, where the circulation is constrained and differences between the experiments are due to the thermodynamic component of climate change. In these regions, nearly all days are warmer in the warmer world experiments, but the largest increases occur on cold days (below freezing) and hot days (above 20 °C). Daily rainfall becomes more variable, even in regions where total rainfall is reduced. Fewer days experience light rain while more days experience heavy rain, and rainfall only increases on less than one day in 10. This single year pair of reanalysis experiments also recovers common patterns of observed and projected long-term changes. For example, Western Mediterranean precipitation declines outside winter, but shows a small increase in winter in the absence of storm track shifts. By anchoring our analysis in weather patterns that have actually occurred, the reanalysis experiments point to how our day-to-day experience of the weather may change in a warmer world.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2548 eISSN: eng

oai:publications.copernicus.org:egusphere141110 2026-05-13 egusphere

Sinnhuber, Björn-Martin Fram in 1893–96, the Sedov in 1937–40, the Tara in 2007–08, and the Polarstern during MOSAiC in 2019–20, as well as from the Soviet/Russian North Pole drift stations, to derive a 130-year record of Arctic transpolar drift speed. The transpolar drift speed already increased significantly during the early 20^th century warming, followed by a period of slowing drift in the 1950s–70s and a strong increase in recent decades, closely following the evolution of Arctic mean temperatures. The observed fractal scaling of the drifts can be explained quantitatively by a Brownian motion random walk process that includes temporal auto-correlation and a mean drift term due to currents and prevailing winds. Comparisons of the sea ice drift speeds with near surface wind observations reveal that the long-term changes in drift speed are not primarily caused by changes in wind speed.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2561 eISSN: eng

oai:publications.copernicus.org:egusphere141119 2026-05-13 egusphere

Zhang, Zhiqiang Kang, Hyun Gu Pöschl, Ulrich Berkemeier, Thomas 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2564 eISSN: eng

oai:publications.copernicus.org:egusphere140964 2026-05-13 egusphere

Karbach, Niklas Pouyes, Pauline Perraudin, Emilie Villenave, Eric Hoffmann, Thorsten 10H₁₈NO₈S⁻ with nitro/sulfonic groups and aromatic fragments). The approach allows to quantify anthropogenic contribution in mixed air masses, demonstrating higher amounts of anthropogenic compounds ratios during Paris-influenced periods. Results validate wind-driven source apportionment for small sample size non-target studies, providing a transferable method for aerosol characterization.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2473 eISSN: eng

oai:publications.copernicus.org:egusphere140883 2026-05-13 egusphere

Eriksson, Albin Wu, Junjie O'Regan, Matt Gustafsson, Örjan 25 (Ice-proxy 25) and marine phytoplankton biomarkers (brassicasterol and dinosterol) from the chronologically well-constrained core 31-PC, sampled at the Southern Lomonosov Ridge during the SWERUS-C3 expedition in 2014. The reconstruction allowed for a direct comparison with previously published terrestrial organic carbon (terrOC) remobilization history from the same core. Our findings revealed a seasonal sea ice cover between 27–26 kyr B.P after the DO-3 warm event, which likely caused more heat and moisture transport from ocean to land and strengthened permafrost thawing along the nearby coastline. A perennial sea ice cover then developed and persisted throughout the Last Glacial Maximum (LGM) to the Younger Dryas (YD), including over the entire B/A warm period. Due to sea-level rise during Meltwater Pulse 1A (MWP 1A, 14.7–13.5 kyr B.P), terrOC remobilization during B/A was rapid but its magnitude smaller when compared to PB and DO-3 in 31-PC, and other records from the Arctic. These records collectively suggest that sea-level rise, rather than sea ice conditions, exerts the primary control on coastal erosion during B/A, while we propose that the perennial sea ice cover may have limited wave-induced coastal erosion on the continental shelf bordering the southern Lomonosov Ridge. A sharp reduction and breakup of the perennial sea ice was observed from the PB to the Early Holocene. Contrary to the B/A, Meltwater Pulse 1B during PB triggered significant coastal erosion and massive terrOC remobilization concurrent with the sea ice decline. The absence of sea ice in parallel to larger coastal erosion compared to B/A implies the role of waning sea ice in enhancing permafrost carbon mobilization along the coastline in this period. In accordance with sea ice records from other Arctic seas, the Holocene record exhibited a period of gradual sea ice expansion. Taken together, these findings highlight sea ice extent as a possible factor regulating coastal permafrost carbon remobilization during the last deglaciation.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2414 eISSN: eng

oai:publications.copernicus.org:egusphere140700 2026-05-13 egusphere

Correa, Sulamita Santos Schultz, Júnia Sadaiappan, Balamurugan Rosado, Alexandre Soares Mundra, Sunil 2) sequestration is commonly attributed to plant-driven processes, while the contribution of soil microorganisms remains comparatively underexplored. This imbalance is particularly relevant in dryland ecosystems, which cover over 45 % of Earth’s land surface and store a substantial fraction of global soil organic carbon. Despite their vast extent and ecological significance, current frameworks often overlook the metabolic potential of microbial communities inhabiting these environments. In drylands, microorganisms have evolved diverse metabolic strategies to capture and store atmospheric carbon, supported by multiple carbon-fixation pathways that extend beyond the Calvin–Benson–Bassham cycle. Here, we examine microbial carbon fixation in dryland ecosystems as an underexplored component of the global carbon cycle. We highlight the diversity, metabolic flexibility, and stress adaptations of carbon-fixing microbes and discuss the dominant pathways supporting carbon assimilation under arid conditions. By integrating evidence across studies, the findings suggest that microbial processes in drylands can contribute to carbon sequestration in ways not fully captured by plant-centered perspectives. This review provides a framework for incorporating microbial metabolic diversity into current models of terrestrial carbon cycling and highlights its relevance for climate change mitigation strategies.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2278 eISSN: eng

oai:publications.copernicus.org:egusphere140671 2026-05-13 egusphere

Guyot, Adrien McGowan, Hamish Filippi, Jean-Baptiste Alonso-Pinar, Alberto Protat, Alain McCarthy, Nicholas Webster, Simon Taylor, Amie

In this study, we review two decades of portable radar observations of wildfires and prescribed burns and present new analyses from a recent deployment of a mobile dual-polarization X-band radar during an extreme wildfire in Eastern Australia. Building on these observations, we introduce a set of radar-derived diagnostics relevant to wildfire intelligence, including plume depth evolution, signatures of pyro-convective dynamics, detection of low-level wind changes, and indicators associated with transitions from pyro-cumulus to deep convection. These diagnostics complement existing satellite and modelling approaches by providing information on processes that are not directly observable from current operational platforms.

Using a Technology Readiness Level (TRL) framework, we assess the maturity of portable radar applications for wildfire monitoring. While fundamental aspects of pyrometeor scattering remain at low readiness (TRL 1–3), repeated field deployments indicate increasing maturity of plume observations (TRL 4–5), with some diagnostic products approaching pre-operational capability. These findings suggest that further progress will depend not only on technical development but also on practical considerations such as deployment logistics, integration with existing systems, and operational evaluation. Overall, portable weather radar may provide an additional component of future multi-sensor wildfire intelligence systems, helping to bridge part of the observational gap between satellite remote sensing and fireground measurements while improving understanding of fire–atmosphere interactions.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2256 eISSN: eng

oai:publications.copernicus.org:egusphere140818 2026-05-13 egusphere

Greve, Peter Schmitt, Amelie U. Schreiber, Sina Jasmin Clédat, Augustin Burek, Peter 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2366 eISSN: eng

oai:publications.copernicus.org:egusphere140919 2026-05-13 egusphere

Pery, Benedict Brindley, Helen Murray, Jonathan Mosselmans, Sophie Panditharatne, Sanjeevani Warwick, Laura Hogan, Robin Huang, Yi Riot-Bretêcher, Benjamin Oetjen, Hilke Schuettemeyer, Dirk L'Ecuyer, Tristan -1 or 15–100 µm) has seldom been observed from satellites. This has contributed to substantial uncertainties in the spectroscopy of water vapour, radiative properties of clouds, and surface spectral emissivity; these in turn limit confidence in modelled FIR energy flows. With the advent of the Polar Radiant Energy in the Far-InfraRed Experiment (PREFIRE), a step is taken towards new, systematic, spectral observations of the Earth in the FIR. Launched in 2024, the two PREFIRE CubeSats offer a new perspective of Earth's outgoing longwave energy with moderate spectral resolution. However, the observational uncertainty budget requires further consolidation.

In this study we assess the accuracy of PREFIRE spectral measurements through a ‘ground-to-space’ closure experiment. Using zenith-viewing observations from the ground-based Far INfrarEd Spectrometer for Surface Emissivity (FINESSE), we gauge the representativity of atmospheric data from in situ sensors and reanalysis. With these data we simulate PREFIRE-observed radiances for an overflight of our field site in eastern Canada. Simulations of the FINESSE radiances are in very good agreement with observations, while those from PREFIRE indicate some bias beyond the calculated uncertainties. We find that atmospheric water vapour specification, uncertain surface properties, and instrument noise dominate the uncertainties. Based on these findings, we highlight proposed techniques for closure experiments using terrestrial and satellite instruments alike. Such experiments will provide a ground-truth for validation of future FIR satellite missions.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2443 eISSN: eng

oai:publications.copernicus.org:egusphere140922 2026-05-13 egusphere

Jakob, Friederike Radenz, Martin Baars, Holger Seifert, Patric Engelmann, Ronny −1 and capture an exceptional moist air intrusion in early July with WVMR values reaching up to 3.9 gkg⁻¹. Two dominant synoptic patterns driving moisture advection toward the Antarctic coast could be identified, producing distinctly different vertical moisture structures. Pattern A, with a low-pressure system northwest of Neumayer Station III seems to be more effective in transporting moisture than a low-pressure system northeast of the Station (pattern B). The lidar measurements are compared to ERA5 reanalysis humidity fields. While ERA5 generally reproduces the moisture distribution reasonably well, it exhibits a dry bias of 0.1 gkg⁻¹ (≈ 10 %) in the lower troposphere. Potential causes of the bias were investigated. The bias shows no clear dependence on the air mass source region, but is dependent on the assimilation cycle, synoptic conditions and the surface type representation in ERA5. These findings suggest that uncertainties in boundary layer mixing processes are a major contributor to the observed dry bias. The results highlight the value of continuous high-resolution water vapor profiling in understanding Antarctic moisture transport and validating reanalysis products.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2445 eISSN: eng

oai:publications.copernicus.org:egusphere140963 2026-05-13 egusphere

Cai, Dongmei Gong, Xianda Zhang, Ruiqi Zhang, Shenyan Cheng, Yuhan Rahaman, Saidur Fang, Yin Chen, Jianmin s + 3n)/o ≤ 1, indicating that OrgSs were dominated by OSs and nitrooxy-OSs (NOSs). Compared with summer, wintertime OrgSs exhibited lower O/C ratios but higher double-bond equivalence and aromaticity, suggesting a stronger influence of anthropogenic emissions and more unsaturated molecular structures. Although OrgSs were mostly present in aliphatic molecular structures, an increase in the number of aromatic OSs in winter revealed an enhanced contribution from anthropogenic sources. Isoprene/monoterpene-derived OSs peaked during the daytime due to photochemical oxidation in summer, whereas monoterpene-derived NOSs were markedly enhanced at night via nighttime NO₃-initiated oxidation. Non-metric multidimensional scaling analysis further revealed that OrgS composition in summer was associated with temperature and O₃ during the day but shifted toward RH-driven processing at night. In winter, inorganic nitrogen and sulfur species, aerosol liquid water content, and particle acidity became more important in shaping OrgS composition, suggesting enhanced aqueous-phase and acid-catalyzed formation. These findings provide molecular-level insights into the sources and formation of atmospheric OrgSs across contrasting environments.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2472 eISSN: eng

oai:publications.copernicus.org:egusphere140862 2026-05-13 egusphere

Ghimire, Ashok Manandhar, Susa Basnet, Tribikram Aryal, Kumar Dhital, Sushant Karki, Reshu Dhakal, Aakriti Krakauer, Nir Pradhananga, Dhiraj 2 yr^-1), growing from 0.77 ± 0.053 km² in 1992 to 2.76 ± 0.13 km² in 2024 (a 258 % increase), with post-2010 expansion accelerating by a factor of 1.35. Lumding Tsho showed a strongly accelerating growth trajectory (R² = 0.96) with a post-2010 rate that more than doubled. The combined estimated additional water volume stored across all four lakes since 1992 approaches 608.6 × 10⁶ m³, representing a GLOF hazard of exceptional and growing scale. The approach demonstrates a scalable and reproducible framework for long-term glacial lake monitoring and hazard assessment, applicable across data-sparse high mountain environment.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2402 eISSN: eng

oai:publications.copernicus.org:egusphere140956 2026-05-13 egusphere

Wu, Rachel Wai-Ying Büeler, Dominik Pyrina, Maria Day, Jonathan Imamovic, Adel Humphrey, Vincent Domeisen, Daniela I.V. 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-2465 eISSN: eng

oai:publications.copernicus.org:egusphere140191 2026-05-13 egusphere

Hung, Joseph Rowe, Penny M. Cox, Christopher J. McCullough, Emily M. Kroll, Liam Ottenheimer, Raia Shupe, Matthew D. Walden, Von P. Strong, Kimberly −1) have been collected at two polar field sites using Atmospheric Emitted Radiance Interferometer (AERI) instruments, two at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Canada (80° N), for which we use data from 2006 to 2022, and another at McMurdo Station (77° S) in Antarctica as part of the Atmospheric Radiation Measurement (ARM) West Antarctica Radiation Experiment (AWARE) project in 2016. We analyze these spectra, with supplementary data from other instruments and models, to compare optical and microphysical properties of moderately thick clouds at Eureka and McMurdo Station, including optical depth, thermodynamic phase, liquid droplet and ice crystal effective scattering radii, and cloud boundaries. We find that the clouds sampled at McMurdo generally feature lower temperatures, smaller liquid droplets, a more concentrated distribution of ice effective radii, less seasonal variability in optical depth, and lower optical thickness because they consist of a higher proportion of ice than those at Eureka. Additionally, both locations have high occurrence rates of supercooled liquid and mixed-phase clouds and exhibit differences between single-phase and mixed-phase microphysics.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-1906 eISSN: eng

oai:publications.copernicus.org:egusphere139845 2026-05-13 egusphere

Narivelo, Herizo Sauvage, Bastien Boersma, Klaas Folkert Smedt, Isabelle Anglou, Isidora Roozendael, Michel Flochmoën, Eric Barret, Brice 3) is a secondary species formed and is considered a hazardous pollutant in the troposphere. Over the recent decades, tropospheric O₃has undergone significant regional variations. This paper focuses on the impact of the evolution of anthropogenic and biomass-burning emissions in the tropics upon tropospheric and the chemical regimes of O₃ using numerical simulations performed of the last 15-years with the GEOS-Chem model. Satellite datasets derived from OMI (HCHO and NO₂) and IASI-SOFRID (CO and O₃) are used as observational constraints to ensure the most reliable representation of BB and ANT emissions. The results show that the simulation (REF) combining GFAS for BB and CAMS for ANT emission provides the best match with the selected satellite observations.

The analysis of REF-simulation shows that positive trends in tropospheric ozone column (TOC) are observed mainly in the Northern Hemisphere, in Asia regions, Temperate North America, Europe, and some tropical regions (Equatorial Asia and Southern Hemisphere South America), driven by increased of ANT and BB emissions and favourable photochemical conditions.

Sensitivity tests with fixing emissions in the tropical band, reveal that the increase in tropical TOC is mainly due to tropical ANT emissions, which occur in chemical regimes nd: transparent by VOC-limited. Further results highlight that effective mitigation of future increases in TOC will depend mostly on control of ANT NOx emissions in tropical regions, where chemical conditions favour high O₃ production, while underlying the marginal role of BB in moderating regional O₃levels.]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-1652 eISSN: eng

oai:publications.copernicus.org:egusphere139741 2026-05-13 egusphere

Hinson, Kyle E. Schlichting, Dylan R. Hetland, Robert D. Engwirda, Darren Smith, Katherine M. Petersen, Mark R. Uyeda, Kaila 2026-05-13 Text application/pdf https://doi.org/10.5194/egusphere-2026-1566 eISSN: eng

oai:publications.copernicus.org:cp135599 2026-05-13 cp

Dhyani, Rupesh Martin-Benito, Dario Verschuren, Louis Matskovsky, Vladimir Bulcke, Jan Doğan, Mehmet Kvaratskhelia, Revaz Köse, Nesibe Güner, Hüseyin Tuncay Schneider, Lea The Caucasus occupies a unique climatic region influenced by European, Mediterranean, and Asian circulation systems, yet it remains underrepresented in tree ring-based Northern Hemisphere temperature proxy networks. Here, we present the first summer temperature reconstruction for the Caucasus region based on maximum latewood density (MXD). We used X-ray micro-computed tomography of tree-ring samples from Pinus sylvestris growing at the upper tree line in the Lesser Caucasus and an ensemble nested regression approach to develop a robust 326 year-long June–September temperature reconstruction (1697–2022). The record explains – regionally unprecedented – 72 % of temperature variance during the instrumental period (1901–2022) and captures distinct interannual and multi-decadal variability including pronounced warming since the 1990s and a strong imprint of major volcanic eruptions. Temperatures in the second half of the 19th century were not significantly colder in the Caucasus than in the second half of the 20th century. The reconstruction highlights the exceptional magnitude and pace of 21st century warming in the region, which is without analogue at least in the past three centuries. Comparison with regional and large-scale temperature reconstructions reveals strong agreement within the Caucasus but negative correlations with Central Europe, indicating distinct temperature variability patterns across Europe and western Asia. Future work should focus on the climate dynamics behind this dipole and the extension of temperature-sensitive tree-ring records in the region.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/cp-22-989-2026 eISSN: 1814-9332 eng

oai:publications.copernicus.org:cp132789 2026-05-13 cp

Gérard, Justin Pohl, Alexandre Sablon, Loïc Huygh, Jarno Silva, Anne-Christine Crucifix, Michel The Devonian period, spanning from 419 to 359 million years ago, was marked by a warmer-than-present climate and recurring ocean anoxic events, with evidence increasingly suggesting a link between these events and astronomical forcing. Here, we explore how astronomical forcing influences ocean oxygenation by modulating the continental weathering flux of phosphate within a Late Devonian climate framework. To investigate this, we performed transient simulations spanning 1.1 Myr, crossing a 2.4 Myr eccentricity node using the cGENIE Earth system model. These simulations were driven by spatially resolved fluxes of reactive phosphorus from continents, computed using the emulator developed by Sablon et al. (2025), trained on GEOCLIM and HadSM3 outputs. Our results provide new evidence supporting eccentricity maxima as a driver of Late Devonian anoxic events. Additionally, global analysis reveals that obliquity variations can leave an imprint on global ocean oxygen levels via their influence on biological productivity, suggesting a potential pathway for obliquity-driven anoxia under greenhouse conditions. Regional analysis revealed pronounced spatial heterogeneity in the biogeochemical response to astronomical forcing. Local ocean circulation emerged as a critical factor in shaping these patterns. The simulations indicate that astronomical forcing can, through its impact on continental weathering fluxes, exert a dominant influence on ocean oxygenation, with regional oxygen concentrations varying by up to 35 % and driving changes in regional anoxic volume of up to 19 %. Finally, these findings help explain why proxy records from different locations may show divergent expressions of astronomical signals, potentially leading to contrasting interpretations of their role in driving ocean anoxia.

]]> 2026-05-13 Text application/pdf https://doi.org/10.5194/cp-22-1003-2026 eISSN: 1814-9332 eng

oai:publications.copernicus.org:cp125562 2026-05-12 cp

Meijers, Maud J. M. Mikes, Tamás Rojay, Bora Çubukçu, H. Evren Aydar, Erkan Lüdecke, Tina Mulch, Andreas Life on Earth has been capitalizing on the C₃ photosynthetic pathway for 2.8 billion years. However, in the world's grasslands that emerged since the Paleogene, C₄ vegetation expanded dramatically between 8 and 3 Ma in response to climatic changes. Here we present the first comprehensive Late Miocene to Holocene δ¹³C soil carbonate record from the Eastern Mediterranean region (Anatolia) to reconstruct long-term geographic distributions of C₃ and C₄ plants, a region with patchy records compared to parts of Africa and Asia. Our results show a colonization of Anatolian floodplains by C₄ biomass by 9.9 Ma, similar to regions in NW and E Africa, followed by a transition from this mixed C₃–C₄ vegetation to C₄ dominance between ca. 7.1 and 4.9 Ma. The transition to C₄ in Anatolia coincides with a similar shift from C₃ to C₄ vegetation in southern Asia and is generally attributed to the Late Miocene Cooling in response to decreasing atmospheric pCO₂. However, the Anatolian paleoecosystem patterns are unique due to a rapid and permanent return to C₃ dominance in the Early Pliocene, which is not observed elsewhere and occurs simultaneously with the disappearance of the open environment-adapted large mammal Pikermian chronofauna. We propose that this return to C₃ vegetation was caused by paleoclimatic processes that regionally shifted precipitation from the warm to the cool season, resembling the modern Mediterranean climate. In conclusion, changes in rainfall seasonality under subhumid climate, rather than increased aridity, drove the demise of C₄-dominated floodplains and the open-environment adapted Pikermian chronofauna at the Eurasian-African crossroads.

]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/cp-22-975-2026 eISSN: 1814-9332 eng

oai:publications.copernicus.org:bg135815 2026-05-12 bg

Burger, Friedrich A. Hofmann Elizondo, Urs Grosselindemann, Hendrik Frölicher, Thomas L. Carbon dioxide removal (CDR) from the atmosphere will likely be required to offset hard-to-abate emissions and limit global warming to well below 2 °C, in line with the Paris Agreement. Among proposed CDR strategies, ocean alkalinity enhancement (OAE) is increasingly discussed because it offers high carbon sequestration potential, long storage timescales, and potentially mitigates ocean acidification. OAE is often envisioned to occur in the open ocean through the dissolution of alkaline mineral powders, such as forsterite, the most abundant form of olivine. Fine-grained powders dissolve near the surface, where the added alkalinity can efficiently enhance oceanic carbon uptake, whereas coarser grains sink and dissolve at depth. Most modeling studies assume complete surface dissolution, leaving the impact of subsurface dissolution on ocean carbon uptake poorly understood. Here, we develop idealized vertical mineral dissolution profiles that vary with environmental conditions and grain size. These profiles are implemented in a comprehensive Earth system model to assess the capture efficiency of OAE, defined as the additional carbon taken up by the ocean per alkalinity added. We find that the efficiency is very sensitive to grain size and may decrease by more than 75 % when grain size doubles, as larger grains release the alkalinity at deeper depth. Efficiency further decreases when particles are not uniformly sized but follow a particle size distribution with the same mean particle volume. In addition, efficiency is time-dependent: it is lower in the first decades of OAE and increases as alkalinity previously released in the ocean interior eventually resurfaces, often far from deployment sites. For forsterite particles with diameter 3.4 µm, the efficiency is less than one-fourth of that achieved with surface alkalinity addition over the first decade, less than one-third over the first 30 years, and less than half over 175 years. Our results indicate that forsterite grain sizes would need to be around 1.7 µm to achieve effective open-ocean alkalinity enhancement and that monitoring, reporting, and verification would be challenged by delayed and spatially dispersed carbon uptake, questioning the suitability of olivine. Minerals with faster dissolution rates may present more viable alternatives when mineral particle properties are closely controlled.

]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/bg-23-3279-2026 eISSN: 1726-4189 eng

oai:publications.copernicus.org:egusphere139827 2026-05-12 egusphere

Jia, Tianlong Chen, Guoding Li, Yao Chang, Xinyu Ehret, Uwe peak) by 13.933 (out-of-domain), with 1% of one-year labeled data. This improved performance stems from the informative feature representations learned from meteorological forcing inputs though CPC pre-training, that enhances prediction ability across diverse basins under data-scarce conditions. Moreover, the advantages of SSL are more obvious for single-basin models when one-year labeled data is available. These results indicate a promising direction for leveraging SSL to develop hydrological foundation models, that have recently revolutionized artificial intelligence research. Hydrological foundation models involve pre-training on large-scale meteorological forcing datasets using self-supervised learning methods (e.g., CPC), and can be adapted to multiple hydrological tasks by model fine-tuning, e.g., simulation of water temperature and soil moisture.]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-1637 eISSN: eng

oai:publications.copernicus.org:egusphere139868 2026-05-12 egusphere

Juncosa Calahorrano, Julieta F. Millet, Dylan B. Wells, Kelley C. Hu, Chengyuan Brewer, Jared F. Payne, Vivienne H. Permar, Wade Hu, Lu Sullivan, Amy P. Ku, I.-Ting Fischer, Emily V. Selimovic, Vanessa Sekimoto, Kanako Lamplugh, Aaron Gkatzelis, Georgios Gilman, Jessica B. Coggon, Matthew Warneke, Carsten 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-1669 eISSN: eng

oai:publications.copernicus.org:egusphere139985 2026-05-12 egusphere

Chishtie, Farrukh Z_CPR > -10 dBZ threshold recommended for the Great Lakes winter precipitation regime further reduces the FAR to 13.8 % (CSI = 58.7 %). The 519 independent METAR comparisons yield a POD of 55.8 % and a low FAR of 9.2 %, confirming the radar based findings through a fully instrument independent pathway and demonstrating that the dominant CloudSat error mode is precipitation detection failure rather than false alarming. The performance degradation relative to the winter only benchmark of Hudak et al. (2008) is shown to arise primarily from near range clutter contamination and year round sampling rather than from algorithmic limitations. Critically, the 70 km threshold is governed by antenna beam geometry rather than radar wavelength and is therefore transferable to validation frameworks employing the new Canadian S band dual polarisation network. Implications for the design of ground validation campaigns for the recently launched EarthCARE Cloud Profiling Radar are discussed.]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-1753 eISSN: eng

oai:publications.copernicus.org:egusphere139974 2026-05-12 egusphere

Marj, Elie Delater, Ambre Gratien, Aline Torrijos, Marie Line Macias Rodriguez, Juan Camilo Cazaunau, Mathieu Pangui, Edouard Bergé, Antonin Gaimoz, Cécile Bertin, Thomas Mebold, Emmanuelle Picquet-Varrault, Bénédicte Doussin, Jean-François Buissot, Clément Lanone, Sophie Coll, Patrice

Two distinct urban atmospheric scenarios were simulated in the CESAM smog chamber: a standard urban (traffic emissions and biogenic precursors) and a biomass burning enhanced. Both scenarios were aged under controlled irradiation with NOx to simulate tropospheric photochemistry.

PM₁ concentrations reached 15 ± 7 µg.m^-3 for the standard scenario and 63 ± 24 µg.m^-3 for the biomass burning scenario, with organic aerosol fractions of approximately 17 % and 40 %, respectively. Gas-phase analysis via proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS) identified 23 volatile organic compounds (VOCs), dominated by oxygenated species (74–77 %). Particle-phase molecular analysis using ultrahigh-performance liquid chromatography electrospray ionization ion mobility quadrupole time-of-flight mass spectrometry (UPLC/ESI-IMS-QTOFMS) revealed 32 distinct compounds. The biomass burning scenario showed elevated source-specific tracers, including a levoglucosan isomer, nitrophenolic compounds (e.g., 3-methyl-4-nitrocatechol, 4-nitroguaiacol), and oxidized aromatics. Volatility distributions estimated via group contribution methods placed most compounds in the semi-volatile, low-volatility, and extremely low-volatility organic compound ranges (C* < 300 µg m^-3), indicating substantial functionalization and partitioning.

These results demonstrate the capacity of simulation chambers to generate reproducible urban aerosol analogues with distinct source-specific molecular signatures and well-characterized volatility distributions. This detailed molecular speciation provides a robust basis for process-oriented model evaluation and opens perspectives for systematic investigations of SOA formation pathways under controlled urban photochemical conditions.]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-1743 eISSN: eng

oai:publications.copernicus.org:egusphere140900 2026-05-12 egusphere

Juurikkala, Kasper Raatikainen, Tomi Krämer, Martina Williamson, Christina J. Laaksonen, Ari The simulations indicate that sustained convective cirrus requires mineral dust concentrations exceeding climatological values by approximately one to two orders of magnitude, corresponding to number concentrations on the order of N_d∼ 1 cm^-3. Under these conditions, heterogeneous freezing on mineral dust dominates ice formation and maintains sufficiently high ice crystal number concentrations to sustain strong longwave cooling at cloud top and preserve convective overturning under shortwave radiative warming. In contrast, homogeneous freezing remains largely suppressed across a wide range of simulated conditions. The direct radiative effect of mineral dust is comparatively weak relative to cloud radiative feedbacks and does not significantly influence cirrus evolution.
The simulated cirrus is also highly sensitive to the choice of deposition ice nucleation parameterization, highlighting a major source of uncertainty in representing dust–ice interactions. Overall, the results identify mineral dust availability as the primary control on dusty cirrus persistence and emphasize the need for improved representation of heterogeneous ice nucleation in atmospheric models.]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2427 eISSN: eng

oai:publications.copernicus.org:egusphere140796 2026-05-12 egusphere

Ouyang, Shubing Li, Daichao Liu, Minjiang Ge, Fengjian Zheng, Xia Li, Yuan Wu, Sheng 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2352 eISSN: eng

oai:publications.copernicus.org:egusphere140870 2026-05-12 egusphere

Casiraghi, Stefano Bertacchi, Daniela Benedetti, Gabriele Mittempergher, Silvia Agliardi, Federico Martinelli, Mattia Bigoni, Francesco Albertini, Cristian Bistacchi, Andrea P₂₁), a key metric often used as a stopping criterion in stochastic DFN simulations, that is derived directly from surface data collected at natural outcrops. We propose a novel approach to define the REA as a range bounded by a lower and an upper limit. The upper limit, often overlooked but nonetheless theorized, identifies the largest representative domain, which is crucial for optimizing computational efficiency. We evaluate the REA range based on three statistical parameters, namely: the shape, mean, and variance of the P₂₁ distributions obtained with progressively increasing scan area sizes. Each statistical parameter is assessed by combining formal statistical tests and diagnostic plots. Within a multi-parametric framework, the method enables a detailed analysis of the statistical behaviour of the dataset, supporting informed decisions in defining the REA range. The methodology is tested on two fractured limestone outcrops with markedly different characteristics: (i) an abandoned quarry in the Murge Plateau (Puglia, Italy) and (ii) the Lilstock Benches in the southern Bristol Channel basin.]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2409 eISSN: eng

oai:publications.copernicus.org:egusphere140669 2026-05-12 egusphere

Marzocchi, Warner Montanari, Alberto the RETURN-uncertainty task force https://www.fondazionereturn.it/en/) – which includes eighteen Italian universities and research centers, the Italian Civil Protection Department, Italian State Railways, Assicurazioni Generali, other profit entities, and one Italian River Basin Authority. Within this initiative, we examined several examples of natural hazard forecasting and projections, from the perspectives of experts in various fields and/or users of these forecasts. The task force found that different hazards share key features and challenges regarding uncertainty understanding, quantification and communication, which may be embedded in a common framework. Such a framework would include a similar hierarchy of uncertainties that defines a complete hazard forecast, which is essential to properly evaluate forecasting models. This work categorizes the common key scientific and communication challenges, propose potential solutions, and intend to stimulate a deeper reflection on these issues.]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2254 eISSN: eng

oai:publications.copernicus.org:egusphere140609 2026-05-12 egusphere

Simon, David J. Schaefer, Jonas Hartmann, Jörg Kirbus, Benjamin Müller, Joshua Hartmann, Markus Wetzel, Bruno Köhler, Laura Jörss, Anna-Marie Weinhold, Kay Herber, Andreas Jurányi, Zsófia Henning, Silvia Roberts, Gregory C. Wendisch, Manfred Pöhlker, Mira L. Stratmann, Frank 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2215 eISSN: eng

oai:publications.copernicus.org:egusphere140887 2026-05-12 egusphere

Noyes, Joanna Palmer, Steven Bennett, Georgina Kolusu, Seshagirirao Bain, Caroline 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2418 eISSN: eng

oai:publications.copernicus.org:egusphere140586 2026-05-12 egusphere

Mandour, Fares Greyeyes-Howell, Jazmin Shewan, Renae Thompson, Lauren Graham, Irene Low, Mike Munson, Matthew Connon, Ryan Cunada, Christopher Emmerton, Craig Olefeldt, David 2) over a five-year period (2020 – 2024) which captured extreme hydroclimatic conditions. These catchments spanned a climatic and permafrost gradient (mean annual temperature -0.2 to -2.8 °C), which provided a space-for-time framework to assess impacts of continued thaw and warming. Our results demonstrated that catchment climate, and thus permafrost conditions, strongly controlled the hydrological response of solute concentrations. Warmer catchments showed a pronounced flushing response where DOC and MeHg concentrations increased by 50 % and 80 %, respectively, as discharge increased from the 10th to 90th percentile. In contrast, colder catchments maintained a chemostatic response, where concentrations remained stable and low despite hydrological variability. Similar climate-hydrology interactions were found for total nitrogen, total phosphorous, and inorganic phosphorous, but not for inorganic nitrogen. It is likely that permafrost conditions in peatlands affect both the production of solutes and their hydrological connectivity to the stream network. The presence of permafrost in peatlands may act to both ensure connectivity during droughts but also preclude full connectivity during floods, yielding the observed patterns. Our findings suggest that ongoing peatland permafrost thaw will increase mobilization MeHg, DOC, and nutrients during high flow periods. This shift necessitates further monitoring to understand the long-term consequences for aquatic ecosystems and northern communities.]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2199 eISSN: eng

oai:publications.copernicus.org:egusphere140508 2026-05-12 egusphere

Glienke, Susanne Bertschinger, Kevin L. Mei, Fan Shilling, John E. 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2141 eISSN: eng

oai:publications.copernicus.org:egusphere140478 2026-05-12 egusphere

Zhang, Fan Han, Tong Zhang, Qiming Wang, Hao Yin, Zhenxuan Wang, Yihe Hu, Biao Tang, Xueyuan Sun, Bo Xiao, Enzhao 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2115 eISSN: eng

oai:publications.copernicus.org:egusphere140402 2026-05-12 egusphere

Stachnik, Artur Gázquez, Fernando Morales-González, Antonio Lope Morellón, Mario González-Ramón, Antonio Moral-Martos, Francisco Jiménez-Espinosa, Rosario Martín-Chivelet, Javier

First we extend the WeMO index forward from 2020, when instrumental measurements end, to 2025 using a physically constrained XGBoost reconstruction based on regional sea-level pressure predictors from San Fernando (Spain) and multiple northern Italian stations, reproducing the published index over 2010–2020 with robust cross-validated performance (R² = 0.85 ± 0.05; RMSE = 0.41 ± 0.07, n = 129 months). Then we analyze 448 rainwater samples collected between 2017 and 2023, aggregated into 154 precipitation-weighted monthly observations of δ¹⁸O, δ²H and δ¹⁷O, together with d-excess and ¹⁷O-excess. Bulk isotope ratios co-vary strongly (ρ > 0.95), allowing δ¹⁸O to represent the dominant network-scale signal.

Random Forest models interpreted using SHAP reveal a clear seasonal reorganization of controls. During the wet season (October–March), δ¹⁸O variability is primarily circulation-driven, with the North Atlantic Oscillation acting as the dominant control and the WeMO providing a consistent secondary modulation. In contrast, during the dry season (April–September), δ¹⁸O is governed by precipitation regime, with precipitation amount overwhelmingly predominating over circulation indices and exhibiting a strongly non-linear, amount-effect response. Back-trajectory clustering of regionally coherent isotope-sampling events supports these contrasting seasonal influences, indicating a small number of recurrent synoptic transport regimes in winter and weaker synoptic organization in summer.

Overall, these results provide a transferable, seasonally calibration that links synoptic circulation and precipitation regime to rainfall δ¹⁸O (and excess parameters) in southeastern Iberia. This innovative framework enables robust interpretation of Mediterranean isotope-based paleoclimate archives by distinguishing circulation-driven wet-season signals from precipitation-regime-driven dry-season variability. It is readily applicable to other climatically complex areas influenced by multiple modes of atmospheric variability and pronounced seasonal contrasts. Furthermore, our results provide a basis for assessing the sensitivity of cave and lake systems to future changes in circulation persistence and rainfall intermittency under ongoing climate change.]]> 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2058 eISSN: eng

oai:publications.copernicus.org:egusphere140333 2026-05-12 egusphere

Khadka, Nitesh Pandey, Vishnu Prasad Watson, C. Scott Zheng, Guoxiong Wu, Tianpei Sharma, Keshab Rawlins, Lauren D. Allen, Simon Gouli, Manish Raj Shrestha, Dibas 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-2011 eISSN: eng

oai:publications.copernicus.org:egusphere140304 2026-05-12 egusphere

Roux, Erwan Tandeo, Pierre Granero Belinchon, Carlos Baklouti, Melika Sommer, Julien Sevault, Florence Somot, Samuel Doury, Antoine Najar, Mahmoud 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-1991 eISSN: eng

oai:publications.copernicus.org:egusphere140291 2026-05-12 egusphere

Behroozi, Abdolmehdi Lawson, Kathryn Shen, Chaopeng 2026-05-12 Text application/pdf https://doi.org/10.5194/egusphere-2026-1982 eISSN: eng 69175258