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2013 items found

10 20 50

The Arctic Weather Satellite radiometer

The Arctic Weather Satellite (AWS), developed by the European Space Agency, highlights a new approach in satellite design, aiming to expand the network of operational microwave sensors cost-effectively. Launched in August 2024, AWS features a 19-channel microwave cross-track radiometer. Notably, it introduces groundbreaking channels at 325.15 GHz. In addition, AWS acts as the stepping stone to a suggested constellation of satellites, denoted as EUMETSAT Polar System Sterna.

Assessment of source regions of the Zambezi River: implications for regional water security

This study focused on the sources of the Zambezi River, revealing new insights into its longest tributary and Angola's key role in its flow. River expeditions and earth observation data show that Angola contributed approximately 73 % of the river's flow upstream of a major floodplain during the 2023 late wet season. We highlight Angola's wetlands, which support river health and help mitigate pollution. These findings stress the need for improved monitoring and regional cooperation in the basin.

Peatland development reconstruction and complex biological responses to permafrost thawing in Western Siberia

Biogeosciences
DOI 10.5194/bg-22-4797-2025
20 September 2025

Western Siberian peatlands regulate global climate, but their response to permafrost thaw remains poorly studied. Our study analyzed peat cores from a peat plateau and a lake edge to track changes over two centuries. We found that permafrost thawing, driven by rising temperatures, altered peatland hydrology, vegetation, and microbial life. These shifts may expand with further warming, affecting carbon storage and climate feedbacks. Our findings highlight early warning signs of ecosystem change.

The historical representation and near-future (2050) projections of the Coral Sea current system in CMIP6 HighResMIP

Ocean Science
DOI 10.5194/os-21-2001-2025
17 September 2025

We examined projected changes in Coral Sea temperature and currents through to 2050 using high-resolution CMIP6 models. Surface warming deepened by 30 m per decade, reaching 400 m by 2050. There was sub-surface cooling between 400 and 600 m. North Vanuatu Jet and North Caledonian Jet transports weakened, and the South Caledonian Jet strengthened. These changes may influence western boundary currents and upwelling dynamics on the Great Barrier Reef.

The 1538 eruption at the Campi Flegrei resurgent caldera: implications for future unrest and eruptive scenarios

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-3421-2025
16 September 2025

We compare recent unrest episodes at the Campi Flegrei caldera (Naples, Italy) with phenomena that occurred during the historical eruption in 1538. Besides proposing a new, accurate reconstruction of the ground movements in the area since the 8th century BCE, we deduce a striking similarity of the present unrest with the precursors to the 1538 eruption. We then infer that, if the ground uplift continues, earthquakes of up to magnitude 5 are expected, as well as a considerable eruption risk in the next few decades.

Drift-aware sea ice thickness maps from satellite remote sensing

The Cryosphere
DOI 10.5194/tc-19-3785-2025
16 September 2025

We developed a new method to map Arctic sea ice thickness daily using satellite measurements. We address a problem similar to motion blur in photography. Traditional methods collect satellite data over 1 month to get a full picture of Arctic sea ice thickness. But in the same way as in photos of moving objects, long exposure leads to motion blur, making it difficult to identify certain features in the sea ice maps. Our method corrects for this motion blur, providing a sharper view of the evolving sea ice.

ESD Ideas: Climate tipping is not instantaneous – the duration of an overshoot matters

Climate tipping points are not committed upon crossing critical thresholds in global warming, as is often assumed. Instead, it is possible to temporarily overshoot a threshold without causing tipping, provided the duration of the overshoot is short. In this Idea, we demonstrate that restricting the time over 1.5 °C would considerably reduce tipping point risks.

Linking crystallographic orientation and ice stream dynamics: evidence from the EastGRIP ice core

The Cryosphere
DOI 10.5194/tc-19-3805-2025
15 September 2025

A better understanding of ice flow requires more observational data. The EastGRIP core is the first ice core through an active ice stream. We discuss crystal orientation data determining the present deformation regimes. A comparison with other deep cores shows the unique properties of EastGRIP and shows that deep ice likely originates from the Eemian. We further show that the overall plug flow of NEGIS is characterised by many small-scale variations, which remain to be considered in ice flow models.

Organic soils can be CO₂ sinks in both drained and undrained hemiboreal peatland forests

Biogeosciences
DOI 10.5194/bg-22-4627-2025
14 September 2025

A 2-year study assessed the soil carbon dioxide (CO₂) balance of drained and undrained hemiboreal peatland forests across Estonia, Latvia, and Lithuania. The study sites included a wide variety of nutrient-rich organic soils, ranging from those near the threshold of organic soil definition to deep peat soils. The soils varied in pH, nutrient levels, and C : N ratio, which contributed to the observed behavior of the soils, demonstrating CO₂ sink and source dynamics under both drained and undrained conditions.

Severe beach erosion induced by shoreline deformation after a large-scale reclamation project for the Samcheok liquefied natural gas (LNG) terminal in South Korea

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-3239-2025
10 September 2025

This paper emphasizes the significance of evaluating changes in nearby shorelines prior to undertaking large-scale coastal construction projects, thereby offering insights into strategies that can minimize potential damage. As a result, the study provides an opportunity to explore the consequences of harbor and fishing port development, as well as large-scale reclamation, which can deform wave fields in coastal areas and intensify coastal erosion.

Multi-centennial climate change in a warming world beyond 2100

A new 10-member ensemble simulation with the state-of-the-art Earth system model was employed to study the long-term climate response to sustained greenhouse warming through to the year 2500. The findings show that the projected changes in the forced mean state and internal variability during 2101–2500 differ substantially from the 21st-century projections, emphasizing the importance of multi-century perspectives for understanding future climate change and informing effective mitigation strategies.

Failure of Marmolada Glacier (Dolomites, Italy) in 2022: data-based back analysis of possible collapse mechanisms

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-3027-2025
5 September 2025

The Marmolada Glacier collapse (3 July 2022), one of the deadliest in the Alps, caused 11 fatalities and occurred during an anomalously warm summer. Analysis links the failure to the combined action of permafrost degradation, elevated ice temperatures, hydrostatic pressure, hydraulic jacking and reduced basal friction. No single factor alone explains the failure. The event highlights how climate-driven thermal and hydraulic factors increasingly threaten the stability of cold mountain glaciers.

Biomechanical parameters of marram grass (Calamagrostis arenaria) for advanced modeling of dune vegetation

This study analyzes seasonal biomechanical traits of marram grass at two coastal dune sites using monthly field and lab data from 2022. Observed differences in density, leaf length, and flower stems were found to be wind-independent and transferable across sites. The results support surrogate model development for numerical and physical experiments alike, where using live vegetation is impractical. Results address the knowledge gap on how vegetation influences dune stability and erosion resistance.

flat10MIP: an emissions-driven experiment to diagnose the climate response to positive, zero and negative CO₂ emissions

This study investigates how climate models warm in response to simplified carbon emissions trajectories, refining the understanding of climate reversibility and commitment. Metrics are defined for warming response to cumulative emissions and for the cessation of emissions or ramp-down to net-zero and net-negative levels. Results indicate that previous concentration-driven experiments may have overstated the Zero Emissions Commitment due to emissions rates exceeding historical levels.

Synoptic observation of a full mesoscale eddy lifetime and its secondary instabilities in the Gulf of Mexico

Ocean Science
DOI 10.5194/os-21-1933-2025
4 September 2025

Oceanic eddies are giant swirling currents that help transport heat, nutrients, and pollutants across the ocean. However, their life cycle has never been observed in detail. Using new satellite data, we tracked an intense eddy in the Gulf of Mexico, describing its life cycle from birth during a 6-month period. Our observations reveal small-scale turbulence surrounding it and interactions with other structures that shape its evolution, validating decades of numerical studies.

CYCLOPs: a Unified Framework for Surface Flux-Driven Cyclones Outside the Tropics

Storms strongly resembling hurricanes are sometimes observed to form well outside the tropics, even in polar latitudes. They behave capriciously, developing very rapidly and then dying just as quickly. We show that strong dynamical processes in the atmosphere can sometimes cause it to become much colder locally than the underlying ocean, creating the conditions for hurricanes to form but only over small areas and for short times. We call the resulting storms "CYCLOPs".

A climate suitability index for species distribution modelling applied to terrestrial arthropods in the Mediterranean region

Climate change threatens biodiversity, especially that of arthropods, by altering species' habitats and ecological roles. This study presents a proof of concept for a novel index that models species distributions based on climatic niches, using regional climate model data and focusing on Mediterranean arthropods. The index enables quick assessments of species' climate resilience and offers potential applications for projecting ecological impacts of future climate changes.

Calibration and performance evaluation of PM _2.5 and NO ₂ air quality sensors for environmental epidemiology

This study evaluates PM _2.5 and NO ₂ sensors for their use in health studies. Sensors were calibrated using data from reference instruments, and regression and machine learning models were evaluated, identifying opportunities and limitations in model transferability in both indoor and outdoor environments and showcasing the importance of integrating metadata such as activity logs and diffusive tubes to improve data validation and interpretation during deployment in the houses of the participants.

Turning regret into future disaster preparedness with no regrets

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-2929-2025
29 August 2025

What do we regret about our disaster preparedness? This paper explores the regrets of 438 citizens who were affected by flooding in Germany in 2021. It shows that regret can primarily be associated with inaction (instead of actions), which contrasts with psychological studies from fields other than disaster science. The findings of this study suggest that the no-regret approach could be a suitable framework for moving towards longer-term disaster preparedness to reduce future regrets.

Impact-based temporal clustering of multiple meteorological hazard types in southwestern Germany

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-2885-2025
27 August 2025

Using loss data, we assess when and how single and multiple types of meteorological extremes (river floods and heavy rainfall events, windstorms and convective gusts, and hail) are related. We find that the combination of several types of hazards clusters robustly on a seasonal scale, whereas only some single hazard types occur in clusters. This can be associated with higher losses compared to isolated events. We argue for the relevance of jointly considering multiple types of hazards.

A numerical model of microplastic erosion, transport, and deposition for fluvial systems

Rivers transport microplastic pollution from its source to its eventual marine sink. Rivers are not simple conveyor belts of this pollution. Microplastic will become entrained within the sediments, becoming part of the river catchment environment. We develop a reduced complexity model to capture the transport and deposition of microplastic. By comparing our model to observations from the Têt River, France, we find that large quantities of microplastic must be stored within the river sediments.

Southern Hemisphere tree rings as proxies to reconstruct Southern Ocean upwelling

The Southern Ocean carbon sink is a balance between two opposing forces: CO₂absorption at mid-latitudes and CO₂ outgassing at high latitudes. Radiocarbon analysis can be used to constrain the latter, as upwelling waters outgas old CO₂, diluting atmospheric radiocarbon content. We present tree-ring radiocarbon measurements from Aotearoa / New Zealand and Chile. We show that low radiocarbon in Aotearoa / New Zealand’s Motu Ihupuku / Campbell Island is linked to outgassing in the critical Antarctic Southern Zone.

Groundwater recharge in Brandenburg is declining – but why?

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-2783-2025
19 August 2025

Brandenburg is among the driest federal states in Germany. The low groundwater recharge (GWR) is fundamental to both water supply and the support of natural ecosystems. In this study, we show that the decline of observed discharge and groundwater tables since 1980 can be explained by climate change in combination with an increasing leaf area index. Still, simulated GWR rates remain highly uncertain due to the uncertainty in precipitation trends.

Insights into supraglacial lake drainage dynamics: triangular fracture formation, reactivation and long-lasting englacial features

We study the evolution of a massive lake on the Greenland Ice Sheet using satellite and airborne data and some modelling. The lake is emptying rapidly. Water flows to the glacier’s base through cracks and triangular-shaped moulins that remain visible over the years. Some of them become reactivated. We find features inside the glacier that stem from drainage events with a width of even 1 km. These features are persistent over the years, although they are changing in shape.

Light scattering and microphysical properties of atmospheric bullet rosette ice crystals

Understanding the interaction between cirrus clouds and solar radiation is critical for modeling the Earth’s climate. A common crystal type found in cirrus clouds is the bullet rosette. Here, atmospheric bullet rosettes measured from jet aircraft are analyzed for their morphological and radiative properties. Atmospheric bullet rosettes are found to be more morphologically complex than previously assumed. This complexity has a significant impact on their radiative properties.

Warnings based on risk matrices: a coherent framework with consistent evaluation

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-2657-2025
13 August 2025

Our research presents a new method for determining warning levels for any hazard. Using risk matrices, our framework addresses issues found in other approaches. Illustrative examples demonstrate how the approach works. A powerful method for evaluating warning accuracy is given, allowing for a cycle of continuous improvement in warning services. This research is relevant to a broad audience, from those who develop forecast systems to practitioners who issue or communicate warnings.

Invited perspectives: Thunderstorm intensification from mountains to plains

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-2629-2025
8 August 2025

Strong thunderstorms have been studied mainly over flat terrain in the past. However, they are particularly frequent near European mountain ranges, so observations of such storms are needed. This article gives an overview of our existing knowledge on this topic and presents plans for a large European field campaign with the goals to fill the knowledge gaps, validate tools for thunderstorm warnings, and improve numerical weather prediction near mountains.

Consequences of the Aral Sea restoration for its present physical state: temperature, mixing, and oxygen regime

The Aral Sea is both an example of large-scale environmental degradation caused by human activity and a message of hope through its partial restoration. Our study shows that the restored part of the Aral Sea is now healthy in terms of vertical mixing and oxygenation. However, small perturbations of water level or transparency could significantly alter the entire ecosystem. The results contribute to understanding the consequences of large-scale lake management worldwide.

Subsurface manifestation of marine heat waves in the southwestern Indian Ocean

Marine heat waves (MHWs) are prolonged periods of extreme ocean temperatures with significant impacts on marine ecosystems. Much research has focused on surface MHWs, but less is known about their subsurface extent. This study uses satellite and in situ data to investigate MHWs in the southwestern Indian Ocean (SWIO). We find that MHWs in the SWIO are closely linked to mesoscale eddies and that strong temperature anomalies extend below surface-identified MHWs.

A Bayesian framework for inferring regional and global change from stratigraphic proxy records (StratMC v1.0)

The chemistry of sedimentary rocks is used to reconstruct past changes in Earth’s climate and biogeochemical cycles. Reconstructing global change requires merging stratigraphic proxy records from many locations, each of which may be incomplete, time-uncertain, and influenced by both global and local processes. StratMC uses Bayesian modeling to see through this complexity, building more accurate and testable reconstructions of global change from stratigraphic data.

Opinion: The role of AerChemMIP in advancing climate and air quality research

The Aerosol Chemistry Model Intercomparison Project (AerChemMIP) aimed to quantify the climate and air quality impacts of aerosols and chemically reactive gases. We review its contribution to AR6 (Sixth Assessment Report of the Intergovernmental Panel on Climate Change) and the wider understanding of the role of these species in climate and climate change. We identify challenges and provide recommendations to improve the utility and uptake of climate model data, detailed summary tables of CMIP6 models, experiments, and emergent diagnostics.

Characterization of the 1966 Camp Century subglacial core: a multiscale analysis

The Camp Century subglacial core stores information about past climates and glacial and interglacial processes in northwestern Greenland. In this study, we investigated the core archive, making large-scale observations using computed tomography (CT) scans and micron-scale observations observing physical and chemical characteristics of individual grains. We find evidence of past ice-free conditions, weathering processes during warmer periods, and past glaciations.

Quantifying the soil sink of atmospheric hydrogen: a full year of field measurements from grassland and forest soils in the UK

We measured soil hydrogen (H₂) fluxes from two field sites, a managed grassland and a planted deciduous woodland, with flux measurements of H₂ covering full seasonal cycles. We estimate annual H₂ uptake of −3.1 ± 0.1 and −12.0 ± 0.4 kg H₂ ha⁻¹ yr⁻¹ for the grassland and woodland sites, respectively. Soil moisture was found to be the primary driver of H₂ uptake, with the silt/clay content of the soils providing a physical barrier which limited H₂ uptake.

Leveraging the satellite-based climate data record CLARA-A3 to understand the climatic trend regimes relevant for solar energy applications over Europe

By compositing trends in multiple climate variables, this study presents emerging regimes that are relevant for solar energy applications. It is shown that the favourable conditions for exploiting solar energy are emerging during spring and early summer. The study also underscores the increasingly important role of clouds in regulating surface solar radiation as the aerosol concentrations are decreasing over Europe and the societal value of satellite-based climate monitoring.

asQ: parallel-in-time finite element simulations using ParaDiag for geoscientific models and beyond

Effectively using modern supercomputers requires massively parallel algorithms. Time-parallel algorithms calculate the system state (e.g. the atmosphere) at multiple times simultaneously and have exciting potential but are tricky to implement and still require development. We have developed software to simplify implementing and testing the ParaDiag algorithm on supercomputers. We show that for some atmospheric problems it can enable faster or more accurate solutions than traditional techniques.

Thermal state of permafrost in the Central Andes (27–34° S)

This study presents the first regional compilation of borehole temperature data from high-altitude permafrost sites in the Andes, providing a baseline of ground thermal conditions. Data from 53 boreholes show thermal characteristics similar to other mountain permafrost areas, but uniquely shaped by Andean topo-climatic conditions. The study emphasizes the need for ongoing monitoring and is a notable collaboration between industry, academia, and regulators in advancing climate change research.

Marine snow morphology drives sinking and attenuation in the ocean interior

Key parameters representing the gravity flux in global models are sinking speed and vertical attenuation of exported material. We calculate, for the first time, these parameters in situ in the ocean for six intermittent blooms followed by export events using high-resolution (3 d) time series of 0–1000 m depth profiles from imaging sensors mounted on an Argo float. We show that sinking speed depends not only on size but also on the morphology of the particles, with density being an important property.

Occupancy history influences extinction risk of fossil marine microplankton groups

We examine how change in a species’ geographic range size over time influences that species’ extinction risk. We analyze instantaneous range size and range size change and how these terms relate to extinction risk in marine microplankton. We find that both the instantaneous range size and the change in range size are informative predictors of extinction. Using predictive models, we also assess extinction probability in four extant groups.

The value of hydroclimatic teleconnections for snow-based seasonal streamflow forecasting in central Asia

Seasonal streamflow forecasts for snowmelt-dominated catchments often rely on snowpack data, which are not always available and are prone to errors. Our study evaluates near-real-time global snow estimates and climate oscillation indices for predictions in the data-scarce mountains of central Asia. We show that climate indices can improve prediction accuracy at longer lead times, help offset snow data uncertainty, and enhance predictions where streamflow depends on in-season climate variability.

Calibrated sea level contribution from the Amundsen Sea sector, West Antarctica, under RCP8.5 and Paris 2C scenarios

Glaciers in the Amundsen Sea region of Antarctica have been retreating and losing mass, but their future contribution to global sea level rise remains highly uncertain. We use an ice sheet model and uncertainty quantification methods to evaluate the probable range of mass loss from this region for two future climate scenarios. We find that the rate of ice loss until 2100 will likely remain similar to present-day observations, with little sensitivity to climate scenario over this short time frame.

Delineating the technosphere: definition, categorization, and characteristics

The technosphere – including buildings, infrastructure, and all other non-living human creations – is a major part of our planet, but it is not often considered as an integrated part of Earth system processes. Here we propose a refined definition of the technosphere, intended to help with integration. We also characterize the functional end uses, map the global distribution, and discuss the catalytic properties that underlie the exponential growth of the trillion tonne technosphere.

Distribution of alkylamines in surface waters around the Antarctic Peninsula and Weddell Sea

During the PolarChange expedition, volatile alkylamines, important players in nitrogen cycling and cloud formation, were measured in Antarctic waters using a high-sensitivity method. Trimethylamine was the dominant alkylamine in marine particles, associated with nanophytoplankton. Dissolved dimethylamine likely originated from trimethylamine degradation, while diethylamine sources remain unclear. These findings confirm the biological origin of alkylamines in polar marine microbial food webs.

Observational constraints suggest a smaller effective radiative forcing from aerosol–cloud interactions

This study addresses the long-standing challenge of quantifying the impact of aerosol–cloud interactions. Using satellite observations, reanalysis data, and a “perfect-model” cross-validation, we show that explicitly accounting for aerosol–cloud droplet activation rates is key to accurately estimating ERFaci (effective radiative forcing due to aerosol–cloud interactions). Our results indicate a smaller and less uncertain ERFaci than previously assessed, implying the reduced role of aerosol–cloud interactions in shaping climate sensitivity.

Simulating vertical phytoplankton dynamics in a stratified ocean using a two-layered ecosystem model

Phytoplankton contribute to half of Earth’s primary production, but not a lot is known about subsurface phytoplankton, living at the base of the sunlit ocean. We develop a two-layered box model to simulate phytoplankton seasonal and interannual variations in different depth layers of the ocean. Our model captures seasonal and long-term trends of the two layers, explaining how they respond to a warming ocean, furthering our understanding of how phytoplankton are responding to climate change.

Long-term observations of atmospheric CO₂ and CH₄ trends and comparison of two measurement systems at Pallas-Sammaltunturi station in Northern Finland

This paper presents long-term observations of atmospheric CO₂ and CH₄ mole fractions and a comparison of two permanent and two mobile measurement systems located in Northern Finland. Furthermore, the observed mole fractions are compared against the mean marine boundary layer product for the Northern Hemisphere. The comparisons of all the systems show good agreement in relation to the World Meteorological Organization/Global Atmosphere Watch network compatibility goal limits for CO₂ and CH₄.

Evidence for multi-rifting in the Variscan–Alpine cycle transition: insights from the European western Southern Alps

We address the transition between the Paleozoic Variscan and Alpine Mesozoic–Cenozoic cycles using tectono-stratigraphy and thermochronology. This transition unfolds through a multi-phase rifting history. An initial rifting stage occurred in the early Permian, followed in the early–middle Permian by a phase of transcurrent tectonics. This was succeeded by a period of erosion/non-deposition in the middle Permian. Crustal stretching in the Middle Triassic marked the onset of the Alpine cycle.

Local versus far-field control on South Pacific Subantarctic mode water variability

Subantarctic mode water in the South Pacific Ocean is important due to its role in the uptake and transport of anthropogenic heat and carbon. The Subantarctic mode water region can be split into two pools using mixed-layer-depth properties. Sensitivity experiments are used to understand the effects of heating and wind on each pool. It is found that the optimal conditions to form large amounts of Subantarctic mode water in the South Pacific are local cooling and upstream warming combined.

First observations of continuum emission in dayside aurora

We studied the first broad band emissions, called continuum, in the dayside aurora. They are similar to Strong Thermal Emission Velocity Enhancement (STEVE) with white-, pale-pink-, or mauve-coloured light. But unlike STEVE, they follow the dayside aurora forming rays and other dynamic shapes. We used ground optical and radar observations and found evidence of heating and upwelling of both plasma and neutral air. This study provides new information on conditions for continuum emission, but its understanding will require further work.

Is drought protection possible without compromising flood protection? Estimating the potential dual-use benefit of small flood reservoirs in southern Germany

In this paper, we use models to demonstrate that even small flood reservoirs – which capture water to avoid floods downstream – can be repurposed to release water in drier conditions without affecting their ability to protect against floods. By capturing water and releasing it once levels are low, we show that reservoirs can greatly increase the water available in drought. Having more water available to the reservoir, however, is not necessarily better for drought protection.

Qualitative risk assessment of sensitive infrastructures at the local level: flooding and heavy rainfall

Natural Hazards and Earth System Sciences
DOI 10.5194/nhess-25-2097-2025
4 July 2025

In post-disaster reconstruction, emphasis should be placed on critical and sensitive infrastructures. In Germany, as in other countries, sensitive infrastructures have not yet been focused on; therefore, we developed a method for determining the risk that sensitive infrastructures are facing in the context of riverine and pluvial flooding. The easy-to-use assessment framework can be applied to various sensitive infrastructures, e.g., to qualify and accelerate decisions in the reconstruction process.