Publikasjonar frå instituttet

• Scarborough, Matthew; Christensen, Kai Håkon; Cerrone, Albert; Kristensen, Nils Melsom & Valseth, Eirik (2026). Modeling the Hydrodynamics in the Oslofjord using an Advanced Circulation Model. Applied Mathematical Modelling. ISSN 0307-904X. s. 117392–117392. doi: 10.1016/j.apm.2026.117392. Fulltekst i vitenarkiv
• Lu, Hongliang; Huang, Baochun; Li, Mingsong; Zhao, Qian; Li, Xiang & Liao, Yilian [Vis alle 11 forfattere av denne artikkelen] (2026). Synchronous end-Permian mass extinction zenith in marine and low-middle latitude terrestrial North China. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 123(45). doi: 10.1073/pnas.2538105123. Fulltekst i vitenarkiv
• Zweigel, Robin Benjamin; Avirmed, Dashtseren; Temuujin, Khurelbaatar; Webster, Clare; Lee, Hanna & Westermann, Sebastian (2026). Forest disturbances and their impact on ground surface temperatures in permafrost-underlain forest in central Mongolia. The Cryosphere. ISSN 1994-0416. 20(2), s. 1001–1023. doi: 10.5194/tc-20-1001-2026. Fulltekst i vitenarkiv Vis sammendrag

  In the forest-steppe ecotone in central Mongolia, forest and permafrost exist close to their climatic limits and are co-located on north-facing slopes. The deciduous forest ecosystems and permafrost on these slopes are linked through interactions in the local energy and water balance. Furthermore, in this region the presence of such permafrost-forest systems provides essential services that supports local livelihoods and ecosystem function. However, forest disturbances that reduce or remove the forest canopies and lead to changes in surface cover could impact ground surface temperatures (GSTs) and potentially lead to permafrost degradation. In this study, we investigate the relationship between different forest states and GSTs at a site in the forest-steppe ecotone. We measured GSTs and surveyed vegetation density and surface cover over two years in an area that features both intact, dead and logged forest and dense stands of young regrowth. Overall, we find GSTs in summer and winter to vary substantially among the forest states, while differences in GST in spring and fall are small. Compared to the intact forest, the annual GST range is increased in the dead and logged forest while it is dampened in stands of young regrowth. Contrary to existing literature, we do not observe a general warming of the ground surface at disturbed sites, but instead find mean annual GSTs at disturbed sites to be 0.5 °C lower than at intact sites. We also find substantial floor vegetation in the dead and logged forest, which has implications for livestock grazing patterns and remote sensing of forest disturbances.

• Shi, Xuewen; Wu, Wei; Li, Dingyuan; Zhao, Lei; Zhu, Yiqing & Luo, Chao [Vis alle 13 forfattere av denne artikkelen] (2026). Pore structure differences and their controlling factors in the shales of different lithofacies in the Lower Cambrian Qiongzhusi Formation, Sichuan Basin. Natural Gas Industry. 46(5), s. 37–53. doi: 10.3787/j.issn.1000-0976.2026.05.004. Fulltekst i vitenarkiv
• Binde, Cornelia Mentzoni; Plaza-Faverola, Andreia; Bünz, S. & Planke, S. (2026). Hydrothermal Vent Complexes Associated With the Infinity Sill (Vøring Basin, Offshore Norway). Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 131(10). doi: 10.1029/2026jb034094. Fulltekst i vitenarkiv Vis sammendrag

  The emplacement of igneous sill intrusions induces rapid heating of host rocks, generating fluids that migrate through structures known as hydrothermal vent complexes (HTVCs). While sill geometry and permeability are considered important factors controlling fluid migration around igneous sill intrusions, the precise mechanisms controlling vent distribution remain unclear. To improve the understanding of the primary controls on the final distribution of HTVCs, we are using a 3D seismic data set from the Mid‐Norwegian margin to analyze HTVCs associated with the ∼56 Ma Infinity Sill. The sill covers 237 km 2 and is associated with 79 HTVCs, 25 of which are classified as mini‐vents. The HTVCs have outer diameters ranging between ∼0.1–2.7 km, are separated by spacings between ∼1.2–4.8 km, have conduit heights ranging between ∼0.6–1.1 km, and variable upper terminations. Our analysis reveals a large‐scale fluid migration pattern dominated by venting along the sill margins and above the sill interior, controlled by factors such as the fluid generation potential around the sill, the density of local highs in the sill interior as well as the mode and heights of sill transgression. Sill geometry is thus found to affect the formation, size and spacing of HTVCs, and is interpreted to constitute a primary control on the final distribution and morphological characteristics of HTVCs. Our findings contribute to a better understanding of subsurface fluid dynamics associated with sill intrusions emplaced in organic‐rich strata and have broader implications for understanding the climatic effects of hydrothermal venting at the Paleocene‐Eocene transition.

• Tao, Jingyi; Li, Fang; Cai, Lei; Zhu, Jiawen; Fei, Kece & Lee, Hanna [Vis alle 7 forfattere av denne artikkelen] (2026). Physical impacts of integrating excess ice into Earth system models on pan‑Arctic permafrost simulations. Atmospheric and Oceanic Science Letters. ISSN 1674-2834. s. 1674–2834. doi: 10.1016/j.aosl.2026.100901. Fulltekst i vitenarkiv Vis sammendrag

  Excess ice refers to ground-ice bodies in permafrost whose volume exceeds the soil pore space, and its melting can cause abrupt permafrost thaw. However, only a few Earth system models (ESMs) currently represent excess-ice processes, with the physical effects remaining unclear. This study quantified how representing excess ice in ESMs affects pan-Arctic permafrost simulations using sensitivity experiments with separate configurations of CESM2 (sub-grid and grid-cell mean schemes) and CAS‑ESM2 (grid-cell mean schemes). Model evaluation showed that both ESMs reasonably simulated the spatial extent of continuous permafrost, but only CESM2 captured discontinuous permafrost. Excess-ice processes reduced the pan-Arctic permafrost extent by 0.16, 2.3, and 0.79 million km2 in CESM2 sub-grid, CESM2 grid-cell mean, and CAS-ESM2 grid-cell mean, respectively. The ALT (active layer thickness) responses also differed among the configurations: in both CESM2 configurations, ALT increased mainly near the southern boundary of continuous permafrost, whereas CAS-ESM2 simulated a more spatially widespread ALT increase. Comparative analysis indicated that using the grid-cell mean scheme yields a larger reduction in permafrost extent compared to the sub-grid approach. These responses suggest that excess ice melt may influence soil hydrothermal conditions by modifying soil moisture, soil thermal conductivity, and heat transfer into deeper soil layers. Compared with CAS-ESM2, CESM2 showed drier soil conditions, lower thermal conductivity, and reduced downward heat transfer in summer, which was consistent with lower soil temperatures and shallower ALT.

• Kürschner, Wolfram Michael; An, Pengcheng; Dons, Carl Erik & Nakrem, Hans Arne (2026). A new record of the conifer Quadrocladus from the Lower Permian Gipshuken Formation, Spitsbergen: implications for palaeobiogeography and palaeoecology. Lethaia: An International Journal of Palaeontology and Stratigraphy. ISSN 0024-1164. 60(3), s. 1–12. doi: 10.18261/let.60.3.1. Fulltekst i vitenarkiv Vis sammendrag

  Here we report the first occurrence of the conifer genus Quadrocladus from the Lower Permian Gipshuken Formation on Spitsbergen, Svalbard, Arctic Norway. The plant-bearing interval occurs within stacked anhydrite–dolomite–marl successions of the Vengeberget member that record a shallow-marine to supratidal sabkha system on an extensive carbonate platform in a semi-arid climate, characterized by hypersalinity, low taxonomic diversity, and evidence for palaeosol formation and vegetation growth on exposed shoals and platform interiors. The Quadrocladus shoots display pronounced xeromorphic traits, notably very short and narrow leaves, consistent with adaptation to water stress in semi-arid, periodically desiccated playa–sabkha settings. Comparison with younger occurrences from the Kungurian Tregiovo flora and Late Permian Angaran and Zechstein successions shows that the Spitsbergen record is so far, both the oldest and the northernmost known occurrence of Quadrocladus. It provides a key high-latitude data point for reconstructing Early Permian vegetation dynamics and the subsequent palaeobiogeographical expansion of Quadrocladus across Pangaea.

• Dahlin, Anders; Braathen, Alvar; Clausen, Ole R.; Faleide, Jan Inge; Senger, Kim & Stemmerik, Lars (2026). Late Palaeozoic faulting and basin formation of the Loppa High area, Barents Sea. Tectonophysics. ISSN 0040-1951. 940, s. 1–20. doi: 10.1016/j.tecto.2026.231412. Fulltekst i vitenarkiv Vis sammendrag

  This study reconstructs the Pennsylvanian–late Permian to Early Triassic tectono-stratigraphic evolution of the Loppa High, a long-lived structural high on the southwestern Barents Shelf. We integrate 2D and 3D seismic surveys and key wells across ∼35,000 km2 to map eight regionally correlatable horizons (H1–H8) tied to the Billefjorden, Gipsdalen, Bjarmeland, Tempelfjorden and Sassendalen groups. Two-way travel-time structure maps, time–stratigraphic thickness maps and detailed fault interpretation (>150 faults) reveal three discrete late Palaeozoic extensional fault systems and a multi-phase tectonic evolution of the Loppa High. An ENE–WSW-striking Carboniferous fault system (C) parallels the Asterias Fault Complex and is linked to regionally widespread late Mississippian–middle Pennsylvanian rifting and development of the northern Loppa High as an early Carboniferous basement high. A Pennsylvanian–early Permian NNE–SSW fault system (P), antithetic to the Bjørnøyrenna Fault Complex, segments the northwestern Loppa High into the Neiden, Børselv and Kråketind sub-highs and controls distribution of Ørn Formation carbonates and Fafner evaporites. The C and P fault systems, along with Pennsylvanian regional transgression, exerted important controls on the depositional architecture. The late Permian–Early Triassic N–S-striking fault system (T) is spatially associated with the West Selis Boundary Fault and records rift reorganization associated with tilting, uplift and erosion of the West Selis Boundary Fault footwall and the final drowning of the Polhem Sub-platform. The results demonstrate that the evolution of the Loppa High is tightly coupled to regional fault trends across the northwestern Barents Shelf and Spitsbergen and reflects structural inheritance relevant to the later opening of the Norwegian–Greenland Sea.

• Sanderson, Benjamin; Sandstad, Marit; Dewey, Maura; Steinert, Norman & Fjeldså, Johannes (2026). METEORv1.6: Spatial climate variability and integrated impact emulation. Geoscientific Model Development. ISSN 1991-959X. 19(19), s. 9263–9288. doi: 10.5194/gmd-19-9263-2026. Fulltekst i vitenarkiv Vis sammendrag

  Climate impact assessment increasingly requires spatially explicit projections with realistic temporal variability at sub-annual resolution. METEORv1.6 extends the established METEOR spatial multi-timescale, multi-forcer climate emulation framework with two major capabilities: (1) a monthly climate variability model that generates realistic sub-annual climate sequences with seasonal cycles and inter-annual variability, enabling the generation of ensemble projections and (2) a modular impact assessment framework that translates climate projections into impact metrics. The monthly climate model represents seasonal harmonics and noise, while preserving covariance structures from the source model. Seasonal cycles are represented through harmonic analysis with temperature-dependent parameterization, enabling non-stationary simulation of seasonal timing shifts under warming. Principal Component Analysis is used to decompose monthly anomalies into spatial modes, then their temporal evolution and climate variability is modeled using Vector Autoregressive with eXogenous variables (VARX) processes. The impact assessment framework provides a standardized interface for ensemble processing and uncertainty quantification through a modular system of impact calculators. The initial case implementation includes heating and cooling degree days calculations which are key drivers in estimating energy sector demand, demonstrating ensemble-based uncertainty propagation from climate projections to impact metrics. Validation against CMIP6 data demonstrates that METEORv1.6 accurately reproduces statistical properties of monthly climate variability for a range of future scenarios when trained on a single scenario from an Earth System Model (together with a CO2 quadrupling idealized experiment). The integrated impact framework enables rapid generation of probabilistic climate risk assessments at the spatial and temporal resolution that sectoral applications require. The implementation is open-source and extensible to additional impact domains.

• Ali, Ahmed M.; Timar, Attila; Boyd, James P.; Barta, Károly; Abdelsamei, Enas & Sheishah, Diaa [Vis alle 9 forfattere av denne artikkelen] (2026). Integrating electrical resistivity tomography–derived metrics with ensemble machine learning to predict the depth-to-water in earthen levees. Engineering Geology. ISSN 0013-7952. 374. doi: 10.1016/j.enggeo.2026.109088. Fulltekst i vitenarkiv Vis sammendrag

  For earthen levees, the dominant failure mechanism is seepage-induced internal erosion. Conventional levee monitoring uses piezometers, which require drilling invasive boreholes yet provide only sparse spatial coverage. In this study, an ensemble machine-learning framework was evaluated for estimating profile-scale depth-to-water (DTW) from three-dimensional electrical resistivity tomography (3D ERT)-derived seepage metrics during a controlled levee-flood experiment along the Körös River, Hungary. Five machine-learning algorithms were compared using leave-one-out cross-validation (LOO-CV) for profile-wise evaluation, complemented by repeated fivefold cross-validation to assess robustness. Feature selection retained three ERT-derived seepage metrics for predicting DTW: leakage distance, time to initial detection, and leakage persistence index. Among the five algorithms, the gradient boosting machine achieved the lowest LOO-CV prediction error, with R2 = 0.983 and a mean absolute percentage error (MAPE) of 1.47%. Augmenting the ERT-derived feature set with the sparsely sampled borehole-derived parameters available in this experiment did not improve predictive performance (MAPE = 1.92%). Shapley additive explanations showed near-equal predictive contributions from all three metrics and revealed consistent model-specific associations across the monitored seepage gradient. These findings indicate that ERT-derived seepage metrics can support profile-scale DTW estimation in fine-grained levees and may reduce dependence on dense piezometric monitoring networks.

• Wang, Heng; Wang, Fuqiang; Xu, Chong-Yu; Zhao, Heng; Huang, Shengzhi & Yang, Huan [Vis alle 9 forfattere av denne artikkelen] (2026). Spatiotemporal evolution and concentration of global meteorological drought from a three-dimensional object-based perspective. Journal of Hydrology. ISSN 0022-1694. 680. doi: 10.1016/j.jhydrol.2026.136473. Fulltekst i vitenarkiv Vis sammendrag

  Drought is a major hydroclimatic hazard, but conventional local or regional indicators can obscure how individual drought events connect and evolve across space and time. Here we track global meteorological drought as three-dimensional (3-D) objects using the 6-month Standardized Precipitation Evapotranspiration Index (SPEI-06) for 1901–2024. We identify 5,822 objects across global land. Compared with early 20th-century levels, the annual drought-object count declined by approximately 20%, whereas the annual total area–duration (AD) increased by about 40%. The 10% of objects with the highest AD account for 75.5% of total AD and 77.0% of cumulative severity. The objects fall into four recurring morphological types, with Type III comprising 19.0% of objects but contributing 50.1% of total AD. Most objects are precipitation-dominant, but the mean relative contribution of atmospheric evaporative demand (AED) is 7.28 percentage points higher in the top 10% by AD than in the remaining objects. Together, these results indicate that global meteorological drought burden is increasingly concentrated in fewer, larger, and longer-lived events, highlighting the value of connected drought-object metrics for drought monitoring and water-resource risk assessment.

• Denton, C. Adeene; Asphaug, Erik; Baijal, Namya & Melikyan, Robert E. (2026). Collisional Capture of an Intact Moon Depends on Strength. Astrophysical Journal Letters. ISSN 2041-8205. 1008(1). doi: 10.3847/2041-8213/ae91e9. Fulltekst i vitenarkiv Vis sammendrag

  The canonical giant impact hypothesis suggests that the proto-Earth’s collision with a differentiated Mars-sized planet, Theia, produced an iron-poor debris disk that accreted to form the Moon. Here, we revisit that hypothesis, for the first time using smoothed-particle hydrodynamics (SPH) simulations with realistic strength. Although negligible compared to stresses in the deep interior, strength in the outer hundreds of kilometers of Theia is shown to hinder its deformation, which alters the transfer of momentum, leading to fundamental differences in Moon formation. For one set of otherwise identical canonical impact parameters, a hot but solid Theia produces an intact Moon, whereas a colder, stronger Theia—i.e., a later Moon-formation scenario—produces a classic protolunar disk. These completely different scenarios arise from different mechanical responses due to temperature and establish an important new connection between giant impact dynamics and the timing and geochemistry of lunar formation.

• Sjur, Anna Lina Petruseviciute; Isachsen, Pål Erik; Nilsson, Johan & Allen, Susan Elizabeth (2026). Nonlinear dynamics of time-variable slope circulation. Ocean Science. ISSN 1812-0784. 22(5), s. 3055–3078. doi: 10.5194/os-22-3055-2026. Fulltekst i vitenarkiv Vis sammendrag

  Bottom topography strongly constrains ocean circulation in the Arctic, and both theory and numerical modeling suggest that nonlinear flow–topography interactions influence slope-following currents. Yet, how such interactions modify the circulation response to time-variable surface forcing remains poorly understood. Using idealized shallow-water simulations of flow over a corrugated slope in a re-entrant channel, we investigate how nonlinear features arise and evolve under oscillatory forcing. We observe both a prograde flow bias (aligned in the direction of topographic Rossby wave propagation) relative to linear estimates, and retrograde flow (opposing wave propagation) exhibiting flow strength saturation once the flow reaches sufficiently strong velocities. To identify the mechanisms responsible for these behaviors, we evaluate integrated momentum budgets. Which terms appear as dynamically relevant, in addition to linear surface and bottom frictional stresses, depends on the choice of integration path: when integrated along isobaths, the nonlinear dynamics appear as a cross-slope relative vorticity flux, whereas integration along straight transects instead highlights momentum flux convergence and topographic form stress. These perspectives can be unified under quasi-geostrophic scaling as describing a flux of potential vorticity (PV). This PV flux is predominantly down-slope and strongest during retrograde phases, resulting in the prograde bias. When retrograde velocities approach the arrest speed of topographic Rossby waves with wavelengths comparable to the corrugation wavelength, the flux increases sharply, halting further acceleration and producing the observed asymmetry. The interplay between forcing timescale and frictional timescale shapes how these nonlinear effects manifest: when the forcing period is comparable to the dampening timescale, the response is strongly low-pass filtered, whereas for much longer forcing periods the flow has time to adjust toward distinct prograde and retrograde states. These results show how flow–topography interactions shape time-variable slope circulation, biasing the flow toward prograde states and limiting retrograde flow strength. Such effects are likely under-represented in coarse-resolution numerical simulations, and highlight the need for improved representations of unresolved topographic interactions.

• Domeier, Mathew Michael; Gallo, Leandro C.; Marcilly, Chloé M. & Torsvik, Trond H. (2026). Quadrupolar sea level fluctuations reveal episodes of rapid polar wander. Science. ISSN 0036-8075. 394(6819), s. 87–90. doi: 10.1126/science.aec8423. Fulltekst i vitenarkiv Vis sammendrag

  True polar wander (TPW) is presently occurring at a rate of ~10 centimeters per year, exceeding the mean rate of differential plate motion. Whether this rate is transient and negligible on geological timescales or whether Earth has experienced rapid TPW lasting millions of years is unclear. Paleomagnetic evidence has been used to propose fast episodes of TPW, but limitations of the paleomagnetic record have precluded definitive results. Rapid TPW will induce global sea level fluctuations associated with relative changes in centrifugal potential, offering an independent test. We evaluated this prediction using continental flooding reconstructions and identified multiple robust quadrupolar patterns since 320 million years ago, confirming that protracted rapid TPW has occurred on Earth and that couplings among Earth’s rotational dynamics, mantle processes, and surface environments can be strongly episodic.

• Barna, Danielle Marie; Engeland, Kolbjørn; Kneib, Thomas; Thorarinsdottir, Thordis Linda & Xu, Chong-Yu (2026). Regional flood frequency analysis at multiple durations: A comparison of duration consistency in quantile and parameter regression techniques. Hydrology Research. ISSN 1998-9563. 57(5). doi: 10.1016/j.hydrch.2026.100002. Fulltekst i vitenarkiv Vis sammendrag

  This study compares two regional flood frequency analysis (RFFA) approaches—the parameter regression technique (PRT) and the quantile regression technique (QRT)—in the context of retention-based hydrologic applications, which require consistent design flood estimates across durations. Using a moving-window approach to estimate average streamflow over fixed durations, we assess whether predicting distribution parameters (PRT) or quantiles directly (QRT) affects the accuracy and duration consistency of flood estimates at ungauged locations. Both methods show similar predictive accuracy at return periods up to 50 years. However, the PRT more reliably preserves duration consistency: at 32 stations, the QRT produced inconsistent estimates at return periods beyond 2 years, while the PRT did not. These inconsistencies were not explained by record length or catchment characteristics. Additionally, at 64 of 239 stations, out-of-sample estimation of the median (index) flood was duration-inconsistent, suggesting difficulties in differentiating between the order of magnitude of floods across durations. Such inconsistencies were not observed in the spread and shape parameters estimated by the PRT. A quantile-based reparameterization of the generalized extreme value distribution was used to align both methods around the median flood, making it easier to compare how the methods behave across durations.

• Wolf, Eva; Stutzmann, Eléonore; Metaxian, Jean Philippe; Nanni, Ugo; Miesen, Floreana M. & Jenkin, Matt [Vis alle 8 forfattere av denne artikkelen] (2026). Locating a complex subglacial drainage network using seismic arrays on Glacier d’Otemma, Switzerland. Journal of Glaciology. ISSN 0022-1430. 72. doi: 10.1017/jog.2026.10200. Fulltekst i vitenarkiv Vis sammendrag

  Glaciers actively store and release meltwater with significant impacts on glacier flow velocity and downstream environments. The evolution of this drainage system is a key component in understanding glacier dynamics. In temperate alpine glaciers, the change of the subglacial drainage network from distributed to channelised is theoretically known, but lacks empirical documentation. As subglacial channels are extremely difficult to access, it is important to test innovative methods for locating them. Here, we use surface seismic monitoring, which enables us to identify the location of multiple subglacial channels below Glacier d’Otemma, Valais, Switzerland. We calculate time delays between pairs of seismic sensors and backtrack source locations. Using matched field processing and beamforming analysis, we obtain spatial and temporal patterns of seismic noise produced by the glacier. This allows us to interpret a possible evolution of the subglacial drainage network from a distributed to an efficient one and locate three distinct subglacial channels in close proximity.

• Heyerdahl, Håkon (2026). Influence of long-term rainfall on the stability of an unsaturated slope in Norway–a case study. Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards. ISSN 1749-9518. doi: 10.1080/17499518.2026.2716834. Fulltekst i vitenarkiv Vis sammendrag

  This paper presents a case study of one out of many landslides that occurred under unusual amounts of rainfall during the autumn of 2000 in Eastern Norway. Most of them were shallow, involving mostly intermediate soils of sand and silt, and were released in slopes that are unsaturated under normal conditions. A case study was conducted for one of the landslide sites. Based on the available data, transient slope stability analyses including seepage through the unsaturated zone were performed. Ground investigations including soil sampling and laboratory testing of unsaturated soil properties were performed, followed by stability analyses taking experimental retention curves and unsaturated strength properties into account. Slopes are theoretically stable for normal annual rainfall of approximately 800 mm per year. For rainfall during the autumn of 2000, with an estimated value of about 240 mm in 30 days, infiltration of surface water results in a gradual decrease in slope stability. Slope failure is caused both by reduced suction in the unsaturated (vadose) zone and by a consecutive rise in the groundwater level. The study shows that the combined effects of cohesion, water permeability and water retention are important for understanding the effects of rainfall on slopes with sandy/silty soils.

• Bredal, Marie Bergvik; Rouyet, Line; Wendt, Lotte; Hindberg, Heidi; Stødle, Daniel & Lauknes, Tom Rune [Vis alle 14 forfattere av denne artikkelen] (2026). Brief communication: InSAR Svalbard Ground Motion Service – observing surface displacements in the High Arctic. Earth Observation (EO). 1(1), s. 121–128. doi: 10.5194/eo-1-121-2026. Fulltekst i vitenarkiv Vis sammendrag

  The InSAR Svalbard Ground Motion Service (GMS) provides open-access surface displacement maps and time series in the Svalbard archipelago, derived from Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR). The service provides seasonal products capturing short-term 2016–2024 displacements and interannual products documenting long-term 2018–2024 velocity trends. InSAR Svalbard covers five areas on Spitsbergen Island (Longyearbyen, Ny-Ålesund, Svea, Hornsund and Kapp Linné). The service consists in a web-based visualisation tool at https://svalbard.insar.no/ (release date: 2 February 2026, last access: 22 September 2026). The products are also distributed at https://doi.org/10.5281/zenodo.18442696 (Bredal et al., 2026a). InSAR Svalbard establishes a foundation for geohazard assessment in Arctic regions and interdisciplinary research on permafrost dynamics, ground stability, and environmental changes.

• Aspaas, Andreas Grøvan; Bievre, Grégory; Lacroix, Pascal; Langet, Nadege; Aga, Juditha & Skrede, Ingrid [Vis alle 9 forfattere av denne artikkelen] (2026). Seasonal and inter-annual evolution of the deformation of two Arctic landslides. Earth Surface Dynamics. ISSN 2196-6311. 14(5), s. 729–761. doi: 10.5194/esurf-14-729-2026. Fulltekst i vitenarkiv Vis sammendrag

  Landslides in glacial and periglacial environments are increasingly affected by climate change, with sudden failures reported in high mountain regions and the Arctic. The complex mechanisms behind these events are often poorly understood due to a lack of dense in situ data. We investigate two slow-moving landslides in Arctic Norway (70° N), the Jettan and Gámanjunni landslides, located approximately 10 km apart: Jettan, a complex slide in micaschist and calcite marble situated below the permafrost boundary, and Gámanjunni, a rotational slide in micaschist situated above the permafrost boundary. Using over a decade of multi-physics observations, including geodetic, borehole, seismic, and hydrological data, we examine surface and subsurface deformation. Both landslides display similar seasonal surface velocity patterns, with peaks in spring and autumn, likely influenced by pore-water infiltration. At Jettan, twelve years of inclinometer data in boreholes reveal a transition from steady state to seasonal deformation in two shear zones. Since 2020, spring accelerations have intensified in years coinciding with deeper snowpacks and associated melt. These observations, together with statistical modeling, suggest that the shear-zones are becoming increasingly localized and sensitive to pore-water pressure. Conversely, autumn acceleration is not seen in localized shear zones but manifests as distributed volumetric deformation. Seismic velocity variations within the landslide body also exhibit seasonal patterns that correspond with geodetic velocity, interpreted as changes in landslide rigidity due to water infiltration. This integrated analysis of surface and subsurface data offers new insights into the evolving deformation of Arctic landslides, emphasizing the influence of hydrological forcings on both seasonal and long-term deformation processes.

• Kierulf, Halfdan Pascal; Maria, Kern, Lisa; Conrad, Clinton Phillips; Kirkvik, Ann-Silje; Hana, Krásná, & Moholdt, Geir [Vis alle 7 forfattere av denne artikkelen] (2026). Effects of glacial loading in Svalbard on the VLBI scale realisation. Journal of Geodesy. ISSN 0949-7714. 100. doi: 10.1007/s00190-026-02121-1. Fulltekst i vitenarkiv Vis sammendrag

  In the realisation of the International Terrestrial Reference System in 2000, and in the realisations since 2008, the scale of the International Terrestrial Reference Frame (ITRF) has been defined based on Very Long Baseline Interferometry (VLBI) and Satellite Laser Ranging (SLR) solutions, whereas ITRF2005 relied solely on VLBI. In the latest ITRF realisation, i.e. ITRF2020 with its first and second updates, VLBI sessions after September 2013 are excluded from the ITRF scale definition due to a detected drift in the VLBI solution with respect to the average scale trend computed from September 1997 until September 2013. Ny-Ålesund station in Svalbard, the northernmost fundamental geodetic station hosting all major techniques, plays a key role in ITRS realisation due to its location. Crustal motion measurements at Ny-Ålesund reveal nonlinear vertical motion, largely explained by elastic deformation caused by thinning glaciers. In the ITRF2020 updates (u2023 and u2024), a discontinuity in August 2016 was introduced for the VLBI station to account for the increasing uplift, reducing the detected scale drift relative to ITRF2020 by approximately 50%. In this study, we analyse the nonlinear vertical motion at Ny-Ålesund, compare it with predicted elastic loading signals arising from glacier thinning, and assess its impact on the VLBI scale estimates. Over the past 25 years, the land uplift rate increased from about 6 mm/year to 14 mm/year, indicating that the vertical displacement through time is not well described by a constant-rate model. The record also shows substantial interannual variability, of which the glacier loading model explains only about 50%. Including a nonlinear station motion model—based on Global Navigation Satellite System (GNSS) observations or loading predictions—for the VLBI station in Ny-Ålesund reduces the relative scale drift by 30–60%. Finally, we discuss alternative approaches to mitigate the negative effects of nonlinearity, such as modelling the elastic glacier signal or better integrating VLBI station motion with GNSS-derived displacement.

• Sereinig, Leon & Herbort, O. (2026). SCoRE: The surface composition of rocky exoplanets. Astronomy and Astrophysics (A & A). ISSN 0004-6361. 713. doi: 10.1051/0004-6361/202659706. Fulltekst i vitenarkiv Vis sammendrag

  Context. The crust composition of rocky exoplanets with a substantial atmosphere cannot be observed directly. However, recent developments are starting to allow for the observation and characterisation of their atmospheres. Understanding the link between atmospheres and crusts could allow for constraints on the crusts’ composition based on atmospheric observations. Aims. We aim to understand the link between the thermal stability of specific condensates and atmospheric compositions. This allows constraints on the mineralogical composition of the surface by potentially observable atmospheric features. In order to achieve this, a grid study of atmospheric and crustal compositions is conducted. Methods. We use a diverse range of total element abundances inspired by various rock compositions as the compositional base for our crust-atmosphere models, for which thermo-chemical and phase equilibrium is assumed. In this work, we investigate a temperature range of 500K to 1000 K and a surface pressure of 1 bar. The resulting atmospheric compositions are classified using atmospheric types based on the most abundant gas-phase elements C, H, N, O, and S. Results. Some of the changes in surface mineralogy coincide with changes in atmospheric type, independent of the given total elemental abundances. In total, a link has been revealed between 23 thermally stable minerals and their corresponding atmospheric types, which is independent of the ratio of the refractory elements present. Especially, the sulphur chemistry of the minerals and the average iron oxidation state can be constrained by the corresponding atmospheric type.

• Wong, E. W.; Werner, Stephanie; Kirchoff, M. R. & Brasser, Ramon (2026). The Enceladian crater production function. Icarus (New York, N.Y. 1962). ISSN 0019-1035. 461, s. 1–18. doi: 10.1016/j.icarus.2026.117300. Fulltekst i vitenarkiv Vis sammendrag

  Interpreting Enceladus’s past and present surface history and interior state remains challenging, owing to uncertain prescription of its impact bombardment history and limited interpretation of its crater statistics. Further progress in understanding its evolutionary history can be achieved with an improved crater chronology model and a thorough assessment of Enceladus’s surface. Here we present the first step in the form of a comprehensive, global crater catalogue with geomorphology survey for Enceladus. From our dataset we build the crater production function (CPF), which is the underlying, unmodified crater size-frequency distribution of the satellite surface, assuming no subsequent modification. We obtained the CPF with a data-driven approach; therefore it makes no assumptions about the impactor source population or planet evolution models or the timing of impact. We fit the CPF with a high-order polynomial as is customary for the Moon and Mars, capturing the slope variations across different crater diameter ranges. The Enceladian CPF generally has a steeper cumulative slope than that of the Moon and Mars for small crater diameters Dcr < 10 km , as well as that of the size-frequency distribution of trans-Neptunian objects. This CPF serves as a critical observational input for an Enceladian crater chronology model, enabling the conversion of crater densities into absolute surface ages. Extending the crater cataloguing and CPF derivation of this study to other Saturnian satellites will determine whether the Enceladian CPF is unique; a shared CPF would indicate a common impactor population, providing observational constraints on the size-frequency distribution of small bodies in the outer Solar System.

• Giannicor, Guido M.; Gianni, Conrado; Gallo, Leandro C.; Sippl, Christian; Arvizu, Harim & Ramos, Victor (2026). Mid-ocean ridge extinctions as amplifiers of plate-tectonic change. Earth-Science Reviews. ISSN 0012-8252. 283. doi: 10.1016/j.earscirev.2026.105685. Fulltekst i vitenarkiv Vis sammendrag

  Plate-tectonic reorganizations involve rapid shifts in plate motions, boundary forces, and tectonic regimes, yet the role of mid-ocean ridge extinctions (MOREs) remains unclear. Here we show that MOREs can amplify reorganizations by removing divergent boundaries, coupling formerly independent plate domains, and enabling stress transmission across extinct ridges. We illustrate this mechanism through four Cenozoic examples closely associated with plate reorganizations: the Wharton, Pacific–Farallon, Shikoku, and Sandra–Malpelo ridges. These cases indicate that, when extinct ridges are incorporated into larger plate circuits undergoing reorganization, they can transmit stresses generated elsewhere in the network toward neighboring margins, consistent with cascading plate-to-plate reorganizations. Strength-profile calculations show that substantial post-MORE strengthening can develop within a few million years after extinction. However, the early coupling inferred from the natural examples is best explained if this strengthening acts on ridge systems already mechanically preconditioned before shutdown, particularly by terminal slow- to ultraslow-spreading that produces a relatively thick axial brittle lithosphere. We therefore propose that inherited preconditioning enables early stress transmission, while subsequent thermo-mechanical strengthening progressively consolidates the extinct boundary. MOREs thus represent evolving mechanical structures that influence how plate-boundary forces are transmitted during plate-network reorganization.

• Zertani, Sascha; Lantman, Hugo Willem van Schrojenstein; Kaatz, Lisa; Chogani, Alireza; Plümper, Oliver & Menegon, Luca [Vis alle 7 forfattere av denne artikkelen] (2026). Grain-scale residual stress distribution and dislocation reorganization during plagioclase-breakdown reactions. Tectonophysics. ISSN 0040-1951. 936, s. 231313–231313. doi: 10.1016/j.tecto.2026.231313. Fulltekst i vitenarkiv Vis sammendrag

  Stress is a key parameter in metamorphic reactions that is difficult to quantify and therefore its role remains a topic of intense debate. To determine the distribution of residual stress during plagioclase breakdown at high-pressure, fluid-present conditions we performed high-angular resolution electron backscatter diffraction (HR-EBSD). These analyses targeted plagioclase adjacent to grain boundaries that contain the initial reaction products of eclogitization. The samples are partially eclogitized granulites from the lower-crustal section exposed on Holsnøy, western Norway. Measurements of residual stress are supplemented by imaging of dislocations by (scanning) transmission electron microscopy and determining compositional variations by scanning electron microscope and electron probe micro analyzer. The results reveal intragrain residual stress heterogeneities in plagioclase on the order of hundreds of megapascals, dominantly caused by the elastic interaction between dislocations with a significant contribution of the developing chemical zonation during the reaction. In the example with less reaction progress, dislocations are scattered, whereas they are parallel to one another and more frequent in Ca-poorer section of the plagioclase. These observations are interpreted to indicate reorganization of dislocations with reaction progress. Dislocation configurations are modified during CaAl-NaSi interdiffusion in plagioclase, which occurs in response to the replacement reaction that forms clinozoisite. This demonstrates that compositional variations in plagioclase during ongoing reactions directly impact the residual stress distribution. Our results suggest that metamorphic reactions may cause significant grain-scale stress heterogeneity which is transient during ongoing reactions.

• Galland, Olivier; Chiacchiera, Sabina; Cal, Hernán de la; Jerram, Dougal Alexander; Lombardo, Ezequiel & Palma, J. Octavio [Vis alle 12 forfattere av denne artikkelen] (2026). The impacts of volcanism on hydrocarbon-bearing sedimentary basins - Examples from the world-class Neuquén Basin case study, Argentina. Global and Planetary Change. ISSN 0921-8181. 257. doi: 10.1016/j.gloplacha.2025.105218. Fulltekst i vitenarkiv Vis sammendrag

  The last two decades of research have highlighted that volcanism occurring in sedimentary basins can have substantial effects on sedimentary formations. In particular, igneous intrusions can trigger the generation of large amounts of greenhouse gases in organic-rich host rocks, leading to dramatic climate change and mass extinctions. Volcanism can also have significant impacts on hydrocarbon-bearing sedimentary basins. The Neuquén Basin, Argentina, is a well-studied example of a hydrocarbon-producing sedimentary basin hosting massive volcanism. The combination of substantial industry subsurface data and high-quality outcrops makes the Neuquén Basin an exceptional geological object to study magma-sedimentary rock interactions and their implications to hydrocarbon systems. This contribution reviews well-studied examples from the Neuquén Basin that illustrate: (1) thermal effects of sills on maturation of the organic matter of the source rock, (2) fracturing processes in igneous intrusions and the host rock, (3) sills as producing fractured reservoirs, (4) intrusion-induced doming as structural trap or as potential fractured reservoir, (5) fluid migration along igneous intrusions, (6) reservoir compartmentalization induced by dykes, (7) generation of bitumen dykes in vicinity of intrusions, and (8) improvement of geophysical imaging using large-scale outcrops. All in all, our review documents various effects of magma-rock interactions in hydrocarbon-bearing sedimentary basins, and highlights the significant scientific value of the Neuquén Basin as a world-class case study for unravelling processes of magma-rock interactions in hydrocarbon-bearing sedimentary basins.

• Biswas, Uddalak; Galland, Olivier & Carlson, Andreas (2026). Laponite® RD and hydroxyethyl cellulose as host rock and magma analogue to simulate a wide range of rheological combinations in the volcanic plumbing system. Tectonophysics. ISSN 0040-1951. 937. doi: 10.1016/j.tecto.2026.231351. Fulltekst i vitenarkiv Vis sammendrag

  Analogue modelling is essential for understanding magma emplacement in the Earth’s crust and requires strict geometric, kinematic and dynamic scaling. Therefore, material selection must satisfy the scaling laws to reproduce the natural rheological variability. Although often represented by end-member rheologies, crustal rocks in nature exhibit complex rheological behaviour. In this study, we analysed two complex materials, Laponite® RD (LRD) and hydroxyethyl cellulose (HEC), to assess their effectiveness as geological analogues for country rock and magma in dyke emplacement experiments. We provide a detailed characterisation of LRD, highlighting its tuneable rheological properties via curing time (t_c). To characterise the complex rheology of the LRD gels, rotational and oscillatory tests, including flow, amplitude, frequency sweep, and creep and recovery tests, were performed at curing times (t_c) ranging from 30 to 240 min. We tested the rheology of aqueous HEC solutions at concentrations of 0.50, 0.75, and 1.00 wt%. Additionally, this study highlights the significant role of surface tension in laboratory analogue experiments, demonstrating the need to minimise interfacial tension by selecting an appropriate magma analogue fluid when using a viscoelastic host. The rheological test results showed that the storage modulus (G^') and yield stress (τ_y) increased systematically with increasing t_c. The flow and surface tension test results indicate that HEC hydrous solutions serve as robust magma analogues, offering variable viscosities with minimal alterations in surface tension and density. Combining the rheological analysis results of LRD and HEC, we propose a new methodology for simulating a wide range of rheological conditions by systematically varying the LRD curing time and employing different concentrations of HEC as a magma analogue. Our approach emphasises precise rheological characterisation together with control of magma-analogue density and surface tension, minimising the interfacial tension and buoyancy contrast with the host for accurate scaling in analogue models of volcanic plumbing systems.

• Kwafo, Samuel; Meert, Joseph G.; Pandit, Manoj K.; Sinha, Anup K. & Verma, Nirmal Kant (2026). Searching for the age of the upper Vindhyan basin, India: A view from paleomagnetism and geochronology. Geoscience Frontiers (GSF). ISSN 1674-9871. 17(1). doi: 10.1016/j.gsf.2025.102168. Fulltekst i vitenarkiv Vis sammendrag

  The closure age of the Proterozoic Vindhyan basin is a long-standing puzzle, unresolved due to inconsistencies between paleontological, geochronological, and paleomagnetic data. Some fossil findings from the Upper Vindhyan basin suggest an Ediacaran closure age, Pb-Pb dating of carbonate units yield dates ranging from ∼750–910 Ma, and detrital zircon data generally support a Kleisian (800–1000 Ma) closure age. In this study, we review published detrital zircon data and apply a statistically robust method to estimate the maximum depositional age (MDA) of the upper Vindhyan Kaimur, Bhander, and Rewa groups. Additionally, we present new paleomagnetic data from the folded Bhander sandstones near the Great Boundary fault to establish the primary nature of the Bhander-Rewa paleomagnetic pole. Our analysis reveals an MDA of 945 ± 7 Ma, which aligns closely with the youngest zircon population in the spectra. This MDA also corresponds to the onset of the Delhi Orogeny to the west of the Vindhyan basin; collisional orogenesis in the Central Indian Tectonic Zone to the south; and more distal high-grade metamorphism and collisional tectonism in the northern Eastern Ghats belt providing a geologically meaningful context for the basin closure age. Our paleomagnetic data offers a robust field test for the Vindhyan pole and we demonstrate that proposals for terminal Tonian closure of the basin (∼850–770 Ma) are incompatible with extant paleomagnetic data from India.

• Yi, Zhiyu; Huang, Ziyu; Yang, Silin; Wang, Fei; Meert, Joseph G. & Zhao, Qian [Vis alle 8 forfattere av denne artikkelen] (2026). Testing the Pangean mega-monsoon hypothesis: New insights from a Late Triassic climatic record from the Zigui Basin, South China. Palaeogeography, Palaeoclimatology, Palaeoecology. ISSN 0031-0182. 693. doi: 10.1016/j.palaeo.2026.113807. Fulltekst i vitenarkiv Vis sammendrag

  Two end-member climate models, the mega-monsoon and the zonal climate pattern, offer competing explanations for the climate of Pangea. Climatic records serve as direct proxies for evaluating these models. This study presents isotopic age and paleoclimatic data from a Late Triassic sequence in the Zigui Basin, South China, to elucidate environmental changes in East Asia and test the climatic models. Multi-proxy records indicate a significant climatic shift from arid to humid conditions within the upper Badong Formation. Usingle bondPb dating of a carbonate layer directly above this climatic transition yields an age of 224.6 ± 5.6 Ma, postdating the Carnian Pluvial Episode. Comparison of the Triassic climatic records across East Asia reveals diachronous humidification. The prolonged aridity in the South China Block (SCB) during the Early to Middle Triassic, coupled with an earlier onset of humidification in the North China Block relative to the SCB, challenges the Pangean mega-monsoon hypothesis.

• Meert, Joseph G.; Pandit, Manoj K.; Sinha, Anup K.; Kwafo, Samuel; Williams, Megan & Panigrahi, Bhagirathi [Vis alle 10 forfattere av denne artikkelen] (2026). Quarter century of Indian Precambrian paleomagnetism: The assembly of Peninsular India and its role in proterozoic supercontinents. Earth-Science Reviews. ISSN 0012-8252. 281. doi: 10.1016/j.earscirev.2026.105600. Fulltekst i vitenarkiv Vis sammendrag

  Over the past 25 years, Precambrian paleomagnetic research in Peninsular India has grown significantly. The quality of data from these studies has improved markedly, resulting in more than a dozen highly reliable paleomagnetic poles from the five cratonic nuclei and the platformal successions that overlie them. This paper provides a comprehensive, site-by-site review of the published paleomagnetic record from the region, including corrections to earlier studies, most of which involve clerical errors in the original publications. In addition, we present previously unpublished paleomagnetic results from the Semri Group (Vindhyan Basin) as well as select new data from the Bastar Craton. Despite these advancements, significant challenges remain, primarily due to poor age constraints within the sedimentary sequences. Numerous paleomagnetic poles from India indicate anomalously high paleolatitudes, particularly from carbonate rocks across six major basins, suggesting widespread remagnetization or unusual climatic conditions. India’s position within Rodinia and Columbia remains uncertain, with existing paleomagnetic data conflicting with recent models. Tonian paleomagnetic data from India and South China suggest a possible linkage between the two regions independent of Rodinia and were interpreted as recording a large-scale episode of true polar wander between ca. 0.82 and 0.77 Ga.

• Hellevang, Helge; Nooraiepour, Mohammad; Sednev-Lugovets, Anton & Dziadkowiec, Joanna (2026). Crystal Growth in Porous Media. InterPore Journal. 3(3). doi: 10.69631/9kd53x06. Fulltekst i vitenarkiv Vis sammendrag

  Crystalline silicate minerals and carbonates make up 90% to 95% of the Earth's lithosphere, the rigid outermost shell comprising the crust and uppermost solid mantle. Crystalline materials are continuously modified by fluid–rock interactions including crystal growth occurring along fractures and within pore spaces. Crystals form under conditions dictated by extrinsic factors, such as temperature, pressure, fluid composition, and pore confinement, as well as intrinsic factors such as crystal structure, chemical bonding, and anisotropy. While the thermodynamic stability and structure of crystals are well established, their rates of heterogeneous nucleation and growth remain poorly constrained. This is particularly true in porous media, where nucleation is frequently a distinct and rate-limiting step rather than a negligible precursor to growth, especially where non-classical pathways preclude a single, well-defined interfacial free energy. In this commentary, we outline how crystal nucleation and growth in porous media control pore-scale structure, flow, and transport, and we evaluate how these processes can be represented in numerical models across scales. We examine the distinct roles of nucleation pathways, growth kinetics, interfacial and confinement effects, and crystallization pressure in governing transient porosity, stress localization, and self-organized crystalline networks. Furthermore, we discuss how fluid flow and mixing modulate where and when these processes occur. These principles are illustrated through examples spanning well-controlled synthetic crystal growth in materials science to geo-energy and geoscience applications, such as basaltic CO2 mineralization, where probabilistic nucleation, reactive transport, and evolving pore architecture jointly control macroscopic behavior. Finally, we assess the potential of machine learning and surrogate modeling approaches to bridge the persistent gap between molecular-scale mechanisms and field-scale predictions. By emphasizing mechanistic understanding over system-specific details, our goal is to help porous media scientists judge when crystallization is likely to matter, and to guide the selection of modeling approaches that remain both physically grounded and computationally tractable. WHY THIS PAPER MATTERS Crystal nucleation and growth can progressively clog pore spaces, redirect fluid pathways, and transform the mechanical and transport behavior of porous rocks across scales. Is it possible to use information we have about nanoscale processes to predict reservoir-scale changes? This InterPore Commentary article synthesizes how confinement, interfacial free energies, and crystallization pressures control where crystals appear, how fast they grow, and when they damage or seal flow networks in natural and engineered systems. It then outlines how machine learning can be used to connect molecular, pore, and field scales for predictive modeling.

• Virkkala, Anna-Maria; Wargowsky, Isabel; Vogt, Judith; Kuhn, McKenzie A.; Madaan, Simran & Windholz, Tiffany [Vis alle 269 forfattere av denne artikkelen] (2026). ABCFlux v2: Arctic–boreal CO2 and CH4 monthly flux observations and ancillary information across terrestrial and freshwater ecosystems. Earth System Science Data. ISSN 1866-3508. 18(9), s. 6357–6409. doi: 10.5194/essd-18-6357-2026. Fulltekst i vitenarkiv Vis sammendrag

  Measurements of surface-atmosphere carbon dioxide (CO 2 ) and methane (CH 4 ) fluxes have been relatively sparse across the Arctic tundra and boreal biomes, causing significant uncertainties in carbon budget estimates from the region. While the availability of Arctic-boreal carbon flux data has increased substantially over the past decade, the data have remained spread across different repositories, scientific articles, and unpublished sources, making it difficult to leverage. Here we present a new dataset of monthly Arctic-boreal carbon fluxes (ABCFlux v2) across terrestrial (wetlands and uplands) and freshwater (lakes and rivers) ecosystems compiled from previous syntheses including the Arctic-boreal CO 2 flux database (ABCFlux v1), the Boreal-Arctic Wetland and Lake Methane Dataset (BAWLD-CH4), and the Global River Methane Database (GRiMeDB). In addition, we consider data from general-purpose (e.g., Zenodo) and flux network repositories, literature, and site principal investigators. The dataset includes surface-atmosphere CO 2 fluxes of gross primary production (GPP), ecosystem respiration (Reco), and net ecosystem exchange (NEE), alongside CH 4 fluxes. For aquatic ecosystems, we split CH 4 fluxes into diffusive and ebullitive flux pathways, and included potential emissions from transient storage in the water column (“storage fluxes”), alongside CO 2 and CH 4 concentrations dissolved in the surface water. Fluxes are measured through a variety of methods including chamber and eddy covariance techniques alongside bubble traps, ice-surveys, and concentration-based turbulence-driven modelling in aquatic ecosystems. The monthly flux data are reported together with supporting methodological and environmental metadata. The resulting ABCFlux v2 has 23 847 flux site-months, 8182 concentration site-months, and 199 seasonal observations from 1024 sites, and includes 56 139 reported fluxes (i.e. sum of GPP, Reco, NEE, and CH 4 fluxes) from the years 1984 to 2024. The majority of monthly observations occurred after 1999. Wetlands had the highest number of site-month observations (8758), followed by boreal forest (6981), lotic ecosystems (6275), lentic ecosystems (3799) and upland tundra (3308). Measurements of CO 2 dominated the dataset across most ecosystem types (25 222) except for lentic ecosystems, where CH 4 flux site-months (3098) were more frequent than CO 2 flux site-months (2915). Overall, ABCFlux v2 includes 160 % more site-months for terrestrial CO 2 flux data compared to ABCFlux v1. Integrating and updating BAWLD-CH4 flux data from growing season averages to monthly fluxes resulted in 5671 site-months of chamber CH 4 data compared to 762 site-years. This collaborative initiative, involving contributions from over 260 researchers, provides a comprehensive overview of the current state of the Arctic-boreal carbon flux network and its data, and serves as an important step in reducing uncertainties in Arctic-boreal carbon budgets and in enhancing our understanding of climate feedbacks. The data can be accessed at ORNL DAAC at https://doi.org/10.3334/ORNLDAAC/2448 (Virkkala et al., 2026).

• Dar, Shaakir; Silantyeva, Olga; Ala-aho, Pertti; Walter, Benjamin; Hulth, John & Hyöky, Valtteri [Vis alle 8 forfattere av denne artikkelen] (2026). Snow Structure Modulates the Isotopic Imprint of Sublimation. EGUsphere. doi: 10.5194/egusphere-2026-2589. Fulltekst i vitenarkiv Vis sammendrag

  Abstract. Sublimation modifies the stable isotopic composition of snow. The physical controls governing this imprint, particularly the interplay between isotopic fractionation, snow structure, and airflow, remain poorly constrained. Current surface-exchange models commonly treat sublimation fractionation as a function of atmospheric forcing and boundary-layer exchange, with limited explicit representation of snow structural state. Here, we present controlled wind-tunnel experiments examining sublimation-driven isotopic changes (δ¹⁸O, δ²H, and d-excess) in three contrasting snow types (laboratory snow, fresh natural snow, and old natural snow) under varied airflow regimes, ambient humidity, and basal-to-air temperature contrasts. We show that airflow is the dominant experimental control on sublimation mass loss, but bulk isotopic change does not scale directly with mass loss, revealing a partial decoupling between sublimation magnitude and isotopic modification. High airflow produced the smallest isotopic change per unit mass loss, consistent with strong turbulent exchange reducing the isotopic imprint of sublimation. However, absolute isotopic change varied systematically with snow structural state, scaling strongly with bulk porosity in natural snow. This structural dependence weakened after mass normalization for δ¹⁸O and δ²H, but persisted for d-excess, suggesting that properties associated with porosity influence effective kinetic fractionation in addition to cumulative isotopic change. Laboratory snow deviated from this behavior: despite overlapping the porosity range of natural snow, it showed no porosity-isotopic change relationship. This suggests that bulk porosity alone is insufficient to capture the structural controls on isotopic response to sublimation. Within a relative snow-type comparison, the Craig–Gordon model systematically overpredicted δ¹⁸O and δ²H enrichment and underpredicted the range of d-excess change. The systematic nature of these discrepancies suggests that parameter uncertainty alone is unlikely to explain the mismatch and points to missing representation of internal vapor transport through the snow pore network. Our study shows that sublimation rate alone is insufficient to predict isotopic modification; snow structural state must be considered alongside atmospheric forcing in models of sublimation-driven isotopic evolution. Snow structural state can therefore impose a systematic overprint on isotopic signals in snow archives and meltwater that structure-independent models are likely to misrepresent.

• Stoutenburg, Emma R.; Caracas, Razvan & Campbell, Andrew J. (2026). Immiscibility between hydrogen and molten iron in planetary cores. Earth and Planetary Science Letters. ISSN 0012-821X. 678, s. 119851–119851. doi: 10.1016/j.epsl.2026.119851. Fulltekst i vitenarkiv Vis sammendrag

  Hydrogen is a likely light element candidate in planetary cores. A hydrogen solubility limit in molten iron could determine the maximum amount of hydrogen possible in the core of a rocky planet. Here, we use ab initio molecular dynamics to investigate the liquid iron-hydrogen system at 10, 50, and 136 GPa and at high temperatures where iron is molten. We calculate Gibbs free energy of mixing at several compositions, from pure iron to hydrogen, using thermodynamic integration. We find that at 10 GPa and 3000 K, there is a liquid-liquid miscibility gap; iron and hydrogen unmix to form Fe0.34H0.66 and H2. At 50 GPa, >2500 K and at 136 GPa, >3500 K, the melts are fully miscible. We extrapolate the Gibbs free energy of mixing to estimate the iron-hydrogen phase diagram down to 1 GPa and in the 1500–6000 K temperature range. As pressure increases, the liquid-liquid miscibility gap shrinks: the solubility limit of hydrogen in liquid iron increases and the closure temperature decreases. At 1 GPa, we estimate the solubility is 18 at% (0.38 wt%) hydrogen at 1500 K. The gap has completely closed by 38 GPa and 3000 K, 69 GPa and 2000 K, and 94 GPa and 1500 K. Thus, small bodies like moons, planetesimals, Mercury, and Mars, which have core-mantle boundary pressures under 30 GPa, are the most limited in the amount of hydrogen their cores can accommodate. On the other hand, iron and hydrogen are fully miscible at the core conditions of larger planets like Earth, Venus, super-Earths, and sub-Neptunes, so their hydrogen concentrations will be limited by sources during formation rather than a thermodynamic limit.

• Okuda, Yoshiyuki; Ohta, Kenji; Mohn, Chris Erik; Nishihara, Yu; Takaichi, Goru & Kawaguchi-Imada, Saori [Vis alle 8 forfattere av denne artikkelen] (2026). Geophysical evidence of a nearly dry bridgmanite in the Earth’s lower mantle. Nature Communications. 17. doi: 10.1038/s41467-026-76621-1. Fulltekst i vitenarkiv Vis sammendrag

  Water in Earth’s mantle plays a crucial role in shaping geological and geochemical processes. While previous electrical conductivity measurements on major mantle minerals have constrained water content in the Earth’s mantle down to the mantle transition zone, the water content of the lower mantle remains experimentally unconstrained. This study measures the electrical conductivity of hydrous (Fe,Al)-bearing bridgmanite, synthesized with Fe and Al compositions representative of peridotitic lithology, at pressures up to 47 GPa and temperatures up to 2210 K. The results demonstrate that proton conduction is the predominant charge transport mechanism in hydrous (Fe,Al)-bearing bridgmanite under the investigated pressure-temperature conditions. Water incorporation markedly enhances the electrical conductivity of bridgmanite, increasing it by approximately an order of magnitude relative to that of dry samples. Extrapolation of the experimental data suggests that bridgmanite in the lower mantle contains less than 40–70 wt. ppm H 2 O near the top and at mid-mantle depths. These findings offer insight into potential hidden water reservoirs in Earth’s lower mantle.

• Backhouse, Nicholas; Thomson, Andrew; Brodholt, John Peter; Hrubiak, Rostislav; Crichton, Wilson & Hao, Ming [Vis alle 9 forfattere av denne artikkelen] (2026). Seismic Velocity of Chlorite Under High Pressure and Temperature and Implications for the Lesser Antilles Subduction Zone. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 131(9). doi: 10.1029/2025jb032997. Fulltekst i vitenarkiv Vis sammendrag

  Chlorite is thought to be one of the major water‐carrying phases in subduction zones, both within the slab and in the mantle wedge. Its presence has previously been linked to common seismological observations at subduction zones, including P and S wave anisotropy as well as high V P / V S ratios (>1.8) in the mantle wedge. However, at present, there are very few high pressure and temperature measurements of the seismic velocity of chlorite at subduction zone conditions, hampering accurate seismological interpretations. This study presents seismic velocities and PVT equation of state measurements of two natural monomineralic chlorite schists, at conditions extending up to ∼5 GPa and 773K. One major finding is the anomalously high V P / V S ratio of these samples, which increase >3 at 5 GPa and 773 K. This result suggests that only a small amount of chlorite (<10%) is required in mantle peridotite assemblages to reproduce the observed V P / V S anomalies >1.8, such as those in the Lesser Antilles subduction zone, and that regions with high V P / V S are not necessarily diagnostic of a free fluid.

• Senger, Kim; Ammerlaan, Fenna; Betlem, Peter; Gaina, Carmen; Galland, Olivier & Grundvåg, Sten-Andreas [Vis alle 21 forfattere av denne artikkelen] (2026). A Field Guide to the High Arctic Large Igneous Province in and Around Isfjorden, Svalbard. Tektonika. 3(2), s. 176–216. doi: https:/tektonika.online/index.php/home/article/view/124/197. Fulltekst i vitenarkiv Vis sammendrag

  The High Arctic Large Igneous Province (HALIP) is a major tectono-magmatic element that affected large parts of the Arctic during the Cretaceous (magmatism occurred from 126 to 78 million years ago [Ma]). In Svalbard, HALIP intrusive and extrusive rocks are grouped and classified as the Diabasodden Suite. Sills and dykes are present throughout Svalbard, emplaced in units stratigraphically ranging from crystalline basement to Jurassic-Cretaceous siliciclastics. Time-equivalent lava flows are exposed on Kong Karls Land in eastern Svalbard. In this contribution, we firstly define and introduce major features of the circum-Arctic HALIP. Secondly, we zoom into Svalbard where we document and summarize the attributes of HALIP outcrops (i.e., the Diabasodden Suite) located in and around Isfjorden, the most accessible location that is reachable on day trips using boats from Longyearbyen. For each of the 15 sites we focus on specific aspects of HALIP characterization, including geochronology, geochemistry and geometry of volcanic and intrusive rocks. We complement field descriptions of the sites with digital geoscientific data, including digital outcrop models and photospheres. Finally, we synthesize the Isfjorden study area in the context of data and knowledge gaps for the HALIP in general. We hope that this contribution will stimulate further HALIP research in Isfjorden and beyond.

• Saha, Chitradeep; Owens, Mathew; Lockwood, Mike; Barnard, Luke; Brehm, Nicolas & Dalla, Silvia [Vis alle 9 forfattere av denne artikkelen] (2026). Physics-Constrained Reconstructions of Sunspot Number from Millennial-Scale Annual Heliospheric Modulation Potential. Solar Physics. ISSN 0038-0938. 301(9). doi: 10.1007/s11207-026-02731-0. Fulltekst i vitenarkiv Vis sammendrag

  Long-term solar magnetic variability governs the space climate conditions. These variations also modulate the galactic cosmic ray influx reaching Earth and subsequently regulate the production of cosmogenic isotopes in Earth’s atmosphere. By harnessing the multi-millennial records of the abundances of these radio-isotopes stored in natural terrestrial reservoirs, such as tree wood and ice sheets, it is possible to reconstruct past solar magnetic activity predating the telescopic era. However, existing regression-based reconstruction methods using isotope data from time series extracted from the reservoirs are often applied to conditions outside the valid parameter range. This can result in a number of problems, including negative sunspot numbers during low solar activity phases, which correspond to statistically permissible extrapolation artefacts but have no physical meaning. To address this, we developed a Monte-Carlo inversion framework consisting of a sequence of physics-based semi-empirical forward models, supplemented by an Approximate Bayesian Computation-based posterior selection, to infer the most plausible temporal evolution of solar magnetic parameters. Our approach produces physically consistent, uncertainty-quantified reconstructions of annually resolved parameters, including sunspot numbers. We apply the method to two modulation potential datasets, namely geomagnetic record from 1845 – 2020, and an annual 14 C estimate over the period 971 – 1932. Our new reconstruction method is designed to yield strictly non-negative sunspot numbers and shows close agreement with direct observations within uncertainty during the telescopic era. These results offer valuable insights into long-term solar variability and provide improved constraints for long-term solar dynamo modelling. The annual-scale reconstructions are also directly usable for solar irradiance estimation, terrestrial climate modelling, and studies of long-term Sun-Earth coupling.

• Zhang, Yiming; Swanson‐Hysell, Nicholas L.; Domeier, Mathew Michael; Gallo, Leandro; Sapienza, Facundo & Afanador, Diego Alberto Osorio (2026). Enriching Paleogeographic Reconstruction Through the Integration of Bayesian Age Models Into Site‐Based Apparent Polar Wander Paths. Journal of Geophysical Research (JGR): Solid Earth. ISSN 2169-9313. 131(9). doi: 10.1029/2026jb034561. Fulltekst i vitenarkiv Vis sammendrag

  Apparent polar wander paths (APWPs) synthesized from paleomagnetic data are foundational to our understanding of the long‐term motions of lithospheric plates. Recent progress has highlighted the advantages of developing such paths from paleomagnetic sites that provide individual snapshots of the ancient geomagnetic field. This approach contrasts with traditional methods that rely on study‐level mean poles—through which it is challenging to incorporate positional and temporal uncertainty. A benefit of the site‐based approach is the flexibility in incorporating temporal information. Rather than relying on a single age assigned to a mean paleomagnetic pole that groups sites together, varied ages can be assigned to individual sites. It also allows the incorporation of stratigraphic superposition constraints, which would otherwise be discarded. We show how probabilistic stratigraphic age models can be integrated into the development of site‐based APWPs. Through resampling from the posterior distributions of such age models, temporal uncertainty can be incorporated while honoring stratigraphic superposition. We illustrate this approach using volcanic and sedimentary successions with U‐Pb age constraints from the late Mesoproterozoic Midcontinent Rift of North America combined with contemporaneous lavas and intrusions from southwestern Laurentia. The result is a site‐based APWP of the Keweenawan Track with significantly higher temporal resolution than a traditional running mean. The high‐resolution path gives insights into motion rates and constrains the timing of change in path direction without requiring additional assumptions. This framework demonstrates how probabilistic treatment of age and positional uncertainties can strengthen quantitative tests of tectonic models.

• Escartín, Javier; Sautter, Benjamin; Gaina, Carmen; Granot, Roi; Petersen, Sven & Pubellier, Manuel (2026). Global geometry of mid-ocean and back-arc ridge systems: Ridge segments, transform faults, and non-transform offsets. Earth-Science Reviews. ISSN 0012-8252. 281. doi: 10.1016/j.earscirev.2026.105633. Fulltekst i vitenarkiv Vis sammendrag

  The total length of the global mid-ocean ridge system length is currently estimated at 50000 to 100000 km. To define in detail the complex structure of divergent plate boundaries, and to accurately evaluate its length and the geometry of ridge offsets, we present the MAPRIDGES database. It provides the first comprehensive global compilation of mid-ocean ridge geometry interpreted from multibeam bathymetry, encompassing in detail individual ridge segments, transform faults, and non-transform offsets (NTOs). The database includes 262 transform faults and 10 transform zones, totalling ∼28.000 km. We quantify for the first time both overlapping and underlapping NTOs at divergent plate boundaries and find a cumulative lateral offset of ∼9.000 km, representing one-third of the cumulative length of transform offsets. The database incorporates 1471 ridge segments reaching a total length of ∼71200 km, while the global ridge length corrected for NTOs overlaps and underlaps amounts to ∼67900 km. Mid-ocean ridge spreading rate exerts a first-order control on the geometry and nature of mid-ocean ridge segmentation. We document that at rates below a spreading rate threshold of ∼80-100 mm/yr, the proportion of overlapping NTOs increases with spreading rate, while the cumulative lateral offset decreases. At rates above this spreading rate threshold there is no apparent dependence of NTOs geometry on spreading rate. We also document that the lateral offset of NTOs and transforms show a significant overlap, with numerous transforms displaying offset lengths below 40 km, and NTOs exceeding 50 km. NTOs affect about 10% of the oceanic crust along-axis, reshaping the lithosphere with tectonic deformation, volcanism, hydrothermal activity and alteration. Consequently, these non-transform discontinuities, together with transform faults, should be systematically included in global assessments of lithospheric accretion, alteration, and associated fluxes of fluids and elements at mid-ocean ridges. We suggest that ridge segmentation and the nature of discontinuities are influenced by multiple factors beyond spreading rate, including mantle temperature, melt supply, and ridge obliquity, in addition to local intra- and inter-segment variability. Analyses of the patterns reported here might help understanding the nature and evolution of magmatic vs. tectonic-dominated ridge segments and their terminations.

• Pharaoh, Tim C.; Rushton, Jeremy; Condon, Dan; Chenery, Simon; Horstwood, Matt & Sahy, Diana [Vis alle 12 forfattere av denne artikkelen] (2026). The Wash Igneous Complex of eastern England: A candidate Avalonian source for Sandbian tephra in Baltoscandia and implications for closure of the Tornquist Sea. Geological Society of America Bulletin. ISSN 0016-7606. doi: 10.1130/b38831.1. Fulltekst i vitenarkiv Vis sammendrag

  The Wash Igneous Complex (WIC) is a component of a Sandbian (Late Ordovician) calc-alkaline magmatic arc that extends from the Lake District in northern England to the Brabant Massif of Belgium, associated with fast subduction of Tornquist ocean crust separating Avalonia (upper plate) and Baltica (lower plate). Buried beneath the East Midlands and The Wash of eastern England, the WIC is likely to comprise an extensive nested caldera system, underlain by a granite batholith, inferred from geophysical data. New whole-rock geochemical data confirm the calc-alkaline character of the WIC and elucidate relationships with other calc-alkaline magmatic complexes in eastern England. Detailed petrographic and geophysical data indicate that the WIC had the capacity to generate super-eruptions. Evidence for ultraplinian volcanism comes from contemporary, regionally distributed and thick metabentonite tephra in Baltoscandia. New, high-precision U-Pb isotopic (chemical abrasion−isotope dilution−thermal ionization mass spectrometry; CA-ID-TIMS) ages of 454.45 ± 0.13/0.23/0.54 Ma and 454.40 ± 0.11/0.22/0.53 Ma (2σ, Sandbian, Late Ordovician) are reported for zircons from a heterolithic dacitic tuff-breccia and a subvolcanic microgranite respectively, recovered from two deep boreholes that intersect the WIC. These dates are identical, within their analytical uncertainties, with equivalently high-precision U-Pb zircon dates for the Kinnekulle Metabentonite (KKMB; Baltoscandia). A population of younger grains from the breccia yielding a CA-ID-TIMS age of 453.70 ± 0.17/0.26/0.55 Ma (2σ) may correlate with the Lower Grimstorp Metabentonite. The matching U-Pb dates and closely comparable apatite microphenocryst chemistry from WIC rocks and the Baltoscandian tephra suggest the WIC as a primary candidate for much of the composite KKMB.

• Marcilly, Chloe M. & Torsvik, Trond H. (2026). Palaeogeography and palaeoelevation through time: controls on weatherability and long-term CO2 evolution. Geological Society Special Publication. ISSN 0305-8719. 565(1). doi: 10.1144/gslspecpub2025-135. Fulltekst i vitenarkiv Vis sammendrag

  Palaeogeography plays a fundamental control on Earth's long-term climate by regulating the efficiency of silicate weathering, the primary negative feedback stabilizing atmospheric CO 2 over geological timescales. Accurate reconstructions of past land distribution, topography and shelf geometry are therefore essential for quantifying weatherability and modelling deep-time climate–carbon cycle interactions. In this study, we present a new Paleozoic palaeogeographic and palaeoelevation model that can be extended for the whole Phanerozoic. Using updated plate tectonic models, fossil-constrained land–sea boundaries, climatically sensitive lithologies and physically informed elevation classes derived from modern Earth statistics, we produce global 10 Myr-interval maps that include seven topographic layers from deep shelves (−200 m) to high mountains (>4 km). Our approach improves estimates of exposed land area, shallow and deep continental shelves, and regions of high weatherability. We show that differences in land distribution within ±10° of the equator and within climatically defined high-weatherability zones, strongly affect CO 2 predictions in carbon-cycle models, particularly during the Early Paleozoic and the Devonian. The new reconstructions refine Paleozoic sea-level estimates and reveal how evolving continental elevations modulated silicate weathering intensity and contributed to transitions between greenhouse and icehouse states, including the initiation and termination of the Late Paleozoic Ice Age.

• Aalstad, Kristoffer; Alonso-González, Esteban; Pirk, Norbert; Westermann, Sebastian; Willmes, Clarissa & Yang, Ruitang (2026). Evolving beyond collapse: an adaptive particle batch smoother for cryospheric data assimilation. Geoscientific Model Development. ISSN 1991-959X. 19(18), s. 8565–8596. doi: 10.5194/gmd-19-8565-2026. Fulltekst i vitenarkiv Vis sammendrag

  We present a new adaptive particle-based data assimilation scheme for cryospheric applications that leverages promising developments in importance sampling. The proposed approach seeks to combine some of the advantages of two widely used classes of schemes: particle methods and iterative ensemble Kalman methods. Specifically, it extends the Particle Batch Smoother (PBS) that is commonly used in cryospheric data assimilation, with the Adaptive Multiple Importance Sampling algorithm. This adaptive formulation transforms the PBS into an iterative scheme with improved resilience against ensemble collapse and the ability to implement early-stopping strategies. As such, computational cost is automatically adapted to the complexity of the problem at hand, even down to the grid-cell and water year level in distributed multiyear simulations. In homage to the schemes that it builds on, we coin this new algorithm the Adaptive Particle Batch Smoother (AdaPBS) and we test it across a range of scenarios. First, we conducted an intercomparison of some of the most commonly used cryospheric data assimilation algorithms using Markov Chain Monte Carlo (MCMC) simulation as a costly gold-standard benchmark in a simplified temperature index model assimilating snow depth observations. We further evaluated AdaPBS by assimilating snow depth observations from the ESMSnowMIP project at 6 different sites spanning 3 continents, using an ensemble of simulations generated with the more complex Flexible Snow Model (FSM2). Our results demonstrate that AdaPBS is a robust and reliable tool, outperforming or at least matching the performance of other commonly used algorithms and successfully handling complex cases with dense observational datasets. All experiments were carried out using the open-source Multiple Snow Data Assimilation System (MuSA) toolbox, which now includes AdaPBS and MCMC among the growing list of available cryospheric data assimilation methods. Beyond our cryospheric focus, the scheme has the potential to be applied directly to the closely related fields of land surface and hydrological data assimilation as well as more general geoscientific Bayesian inference problems.

Sjå alle arbeida i NVA

• Olsen, Are; Årthun, Marius; Dodd, Paul A.; Jentoft, Sissel; Renaud, Paul Eric & Müller, Malte [Vis alle 30 forfattere av denne artikkelen] (2026). Polhavet / Arctic Ocean 2050 Science Plan. doi: 10.7557/ph.8956. Fulltekst i vitenarkiv
• Haualand, Kristine Flacké; Pontoppidan, Marie; Åkesson, Henning & Sauter, Tobias (2026). Glacier thinning causes warmer and drier regional climate at the Jostedalsbreen ice cap´. Fulltekst i vitenarkiv
• Li, Lu; Xie, Kun; Chen, Hua; Sobolowski, Stefan Pieter; Paasche, Øyvind & Xu, Chong-Yu (2026). Is bias correction necessary for CPRCM-driven flood simulation in mountainous region? doi: 10.5194/egusphere-egu26-14380. Fulltekst i vitenarkiv Vis sammendrag

  Convection-permitting regional climate models (CPRCMs) at kilometer scale can better represent intense precipitation, yet their added value for flood-risk applications is still limited and often inconsistent. A key reason is the presence of systematic biases in precipitation and temperature over complex terrain, which may strongly affect hydrological response. To address whether bias correction is necessary when using CPRCM forcing for flood modelling in complex terrain, we run WRF-Hydro with raw and bias-corrected 3-km HCLIM3 precipitation and temperature for two contrasting basins spanning coastal to mountainous terrain in western Norway: Røykenes (coastal, rainfall-driven floods) and Bulken (mountainous, snowmelt-influenced floods). We further compare two widely used bias-correction approaches, i.e., Quantile Mapping (QM) and Distribution Delta Mapping (DDM), applied to precipitation and temperature prior to the hydrological simulations. The results show that bias correction reduces mean biases in both variables, but its effectiveness depends on basin type and metric. In Røykenes basin, QM does not adequately correct annual maximum 1-hour precipitation, whereas DDM provides a better adjustment of extreme precipitation. For temperature, the correction reduces absolute bias relative to raw HCLIM3 but also shifts the bias from cold to warm. In terms of hydrological performance, raw HCLIM3 forcing already yields a small flood-peak bias in Røykenes basin (~3% underestimation), while bias-corrected forcing can further worse this peak underestimation. In Bulken basin, temperature correction improves both flood peaks and flood seasonality, underscoring the strong sensitivity of snowmelt-influenced floods to temperature errors. By contrast, precipitation correction in this mountainous basin degrades flood-simulation skill. Overall, our results show that CPRCM forcing can be highly informative for flood simulations, but the benefits depend on process regime: temperature correction is critical for snowmelt-dominated basins, while precipitation correction over mountains requires particular caution.

• Nielsen, Pål Ringkjøb; Bakke, Jostein; Paasche, Øyvind; Cederstrøm, Jan Magne; Hardeng, Johannes & Young, George Edward (2026). Holocene flood frequency at Vangsvatnet, western Norway, reconstructed from lake sediments. Fulltekst i vitenarkiv Vis sammendrag

  Instrumental records reveal an increase in precipitation in Norway over the past 120 years, with a marked rise after 1980 CE, leading to more frequent and severe floods—a trend consistent across Europe. Palaeoflood reconstructions from Southern Norway indicate non-stationary flood frequencies over the Holocene, with a notable regime shift around 4000 years ago. However, the seasonal drivers of these floods remain poorly understood. This study presents an 8000-year flood record from Lake Vangsvatnet, Western Norway, combining high-resolution computed tomography (CT) scanning, X-ray fluorescence (XRF), grain size analysis, and radiocarbon dating to differentiate between seasonal flood deposits (spring snowmelt vs. autumn rainfall). The 11-meter sediment core reveals distinct flood layers classified as minerogenic (M), organic (O), and mixed (MO), linked to varying hydrological conditions. Historical discharge data (1892–2016 CE) validate the sedimentary record, with O-layers corresponding to spring/snowmelt floods and M/MO-layers to autumn/rainfall-induced events. The record shows fluctuating flood frequencies, with peaks at 6000–5300 and 1400 cal yr BP to present. A seasonal shift from rainfall-dominated to snowmelt-dominated floods occurred around 3100 cal yr BP, coinciding with regional cooling. The last 500 years exhibit the highest flood frequency of the entire record. These findings highlight the sensitivity of flood regimes to climatic and anthropogenic forcings. Under future warming, reduced snowpack may diminish spring floods, while intensified autumn rainfall could increase flood risks.

• Dannevig, Halvor; Løseth, Kristin; Lunde, Albert; Isaksen, Ketil & Etzelmüller, Bernd (2026). Norske fjell blir farlegare. Fulltekst i vitenarkiv Vis sammendrag

  Det som før var ein enkel fjelltur, kan brått bli livsfarleg.

• Eayrs, Clare; Labe, Zachary; Massonnet, Francois; Tian, Tian & Müller, Malte (2026). Reliable AI Sea Ice Forecasts Depend on Sustained Observations. EOS. ISSN 0096-3941. Fulltekst i vitenarkiv Vis sammendrag

  Sea ice is a fundamental regulator of Earth’s climate and an increasingly urgent forecast target itself. Can we trust the AI systems now being built to predict it?

• Svensen, Henrik Hovland (2026). Å gjøre CO2 om til stein. Fulltekst i vitenarkiv
• Svensen, Henrik Hovland (2026). Masseutryddelser og klimaendringer gjennom de siste 500 millioner år. Fulltekst i vitenarkiv
• Schmid, Sarah Ruth & Lundmark, Anders Mattias (2026). The nudging toolbelt. doi: https:/www.mn.uio.no/geo/english/about/organisation/geodidactics/research/nudge.html. Fulltekst i vitenarkiv
• Lundmark, Anders Mattias & Schmid, Sarah Ruth (2026). Nudging for learning and teaching. doi: https:/www.mn.uio.no/geo/english/about/organisation/geodidactics/research/workshop-the-nudging-toolbelt.html. Fulltekst i vitenarkiv
• Wagner, Johannes; Krinner, Gerhard; Merikanto, Joonas; Laumann, Gregor; McGovern, Frank & Kotova, Lola [Vis alle 42 forfattere av denne artikkelen] (2026). Maximizing the synergy of European research Governance and Innovation for Climate Action (MAGICA): Strategic Research and Innovation Agenda for Climate Change Science (2026-2035). doi: 10.25424/CMCC-76KB-3540. Fulltekst i vitenarkiv
• Andersen, Gard Lilledal (2026). Intervju om Osloriften på God morgen Norge, TV2. [TV]. TV2. Fulltekst i vitenarkiv
• Bünz, Stefan; Yu, Jiaxin; Sivertsen, Anders; Lebedeva-Ivanova, Nina & Planke, Sverre (2026). Time-lapse seismic analysis over basaltic rocks at Skoll High (Vøring Basin) to support CO₂ storage monitoring strategies. doi: https:/meetingorganizer.copernicus.org/EGU26/session/55982#Posters_on_site. Fulltekst i vitenarkiv Vis sammendrag

  Basaltic rocks host abundant pore space and reactive mineral phases that make them attractive targets for CO₂ storage via mineral trapping, yet their seismic response presents significant challenges for monitoring due to strong scattering and wavefield complexity. Within the framework of the PERBAS project (Permanent sequestration of gigatons of CO2 in continental margin basalt deposits), we assess the potential for high-resolution time-lapse (4D) seismic methods to detect subsurface changes in a basalt-dominated offshore setting and to inform efficient monitoring strategies applicable to future CO₂ storage operations. We analyze two P-Cable high-resolution 3D seismic volumes acquired over Skoll High in the Vøring Basin (mid-Norwegian margin), a 2022 baseline and a 2024 repeat survey that reoccupied 17 of 26 original sail lines. Both datasets used consistent acquisition parameters and were processed with a uniform workflow incorporating geometry assignment, noise attenuation, amplitude correction, and high-resolution binning (6.25 × 6.25 m). A key objective was to maximize seismic repeatability as a prerequisite for robust 4D analysis in basaltic terrain. Time-lapse calibration included cross-correlation for phase and time shifts, shaping filters, cross-correlation statics, and amplitude cross-normalization. Different calibration windows were defined above the top basalt and including the top basalt sequence in order to analyze the impact of non-repeatable signal variability within the volcanic complex. The normalized root-mean-square (NRMS) metric was used to quantify repeatability across the repeat survey area. Our initial results indicate that high spatial repeatability is attainable with P-Cable 3D seismic data in a basalt setting when acquisition and processing are carefully controlled, though areas of complex basalt morphology and structural heterogeneity exhibit higher NRMS values. Difference volumes highlight regions of anomalous repeatability that correlate with geological features. These findings underscore both the promise and limitations of time-lapse seismic monitoring in basaltic reservoirs and contribute to establishing realistic detection thresholds and optimized survey designs for CO₂ storage monitoring. This study expands the understanding of seismic repeatability in volcanic margin environments and provides groundwork for advancing cost-effective monitoring strategies in basalt-hosted storage projects.

• Wit, Heleen de; Worner, Elisabeth-Christina; Lu, Xiang; Balkoni, Areti; Jackson-Blake, Leah Amber & Berntsen, Terje Koren [Vis alle 8 forfattere av denne artikkelen] (2026). Integration of terrestrial and aquatic carbon fluxes in a boreal headwater catchment. Fulltekst i vitenarkiv
• Andersen, Gard Lilledal (2026). Gjest i Abels tårn. [Radio]. NRK P2. doi: https:/radio.nrk.no/podkast/abels_taarn/l_4115f770-e95c-45d4-95f7-70e95c55d42b?utm_source=nrkradio&utm_medium=delelenke-web&utm_content=podcast%3Al_4115f770-e95c-45d4-95f7-70e95c55d42b. Fulltekst i vitenarkiv
• Shetty, Shobitha; Stebel, Kerstin; Hamer, Paul David; Hassani, Amirhossein; Salamalikis, Vasileios & Chen, Jiayao [Vis alle 9 forfattere av denne artikkelen] (2026). Machine-learning data fusion of model, satellite and low-cost sensor observations for 1-km PM2.5 mapping across Europe. Fulltekst i vitenarkiv
• Kürschner, Wolfram Michael; An, Pengcheng; Dons, Carl Erik & Nakrem, Hans Arne (2026). A new record of the conifer Quadrocladus from the Lower Permian Gipshuken Formationon Spitsbergen - implications for palaeobiogeography and palaeoecology. doi: https:/indico.uni-muenster.de/event/4105/book-of-abstracts.pdf. Fulltekst i vitenarkiv Vis sammendrag

  We report the first systematic description of Permian plant macrofossils from the Lower Permian Gipshuken Formation on Spitsbergen, Svalbard, Arctic Norway. Several conifer shoots from a fossil plant horizon in the lower Vengeberget member are assigned to the genus Quadrocladus. The plant-bearing interval occurs within stacked anhydrite–dolomite–marl successions of the Vengeberget member that record a shallow marine to supratidal sabkha system on an extensive carbonate platform in a semi arid climate, characterized by hypersalinity, low taxonomic diversity, and evidence for palaeosol formation and vegetation growth on exposed shoals and platform interiors. The Quadrocladus shoots display pronounced xeromorphic traits, notably very short and narrow leaves, consistent with adaptation to water stress in semi arid, periodically desiccated playa–sabkha settings. Comparison with younger occurrences from the Kungurian Tregiovo flora and Late Permian Angaran and Zechstein successions shows that the Spitsbergen record is so far, both the oldest and the northernmost known occurrence of Quadrocladus. These findings imply a boreal, semi arid origin for this xeromorphic, stress tolerant conifer and provide a key high latitude data point for reconstructing Early Permian vegetation dynamics and the subsequent palaeobiogeographic expansion of Quadrocladus across Pangaea.

• Tjoflot, Gunn Kristin (2026). Feltarbeid i Patagonia: Masteroppgaven i geologi tok Ole-Jacob til Sør-Amerika - Institutt for geofag. Fulltekst i vitenarkiv
• Svensen, Henrik Hovland (2026). Om Oslofeltet og grunnen under føttene. Fulltekst i vitenarkiv
• Svensen, Henrik Hovland (2026). Øygarden. Fulltekst i vitenarkiv
• Svensen, Henrik Hovland (2026). Abels tårn - Hvor vakker er naturen? [Radio]. NRK P2. Fulltekst i vitenarkiv
• Svensen, Henrik Hovland (2026). Åpent atelier. Fulltekst i vitenarkiv
• Svensen, Henrik Hovland (2026). Lagring av CO2 i undergrunnen. Fulltekst i vitenarkiv
• Svensen, Henrik Hovland (2026). Lagring av CO2 i undergrunnen. Fulltekst i vitenarkiv
• Andersen, Gard Lilledal (2026). Steinriket Oslo. Bygningssteinvandring for Norske landskapsarkitekters forening. Fulltekst i vitenarkiv
• Carlsen, Eira Catharine Lødrup; Pismeniuk, Anfisa; Wei, Jing; Ippach, Mats Rouven; Dörsch, Peter & Westermann, Sebastian [Vis alle 9 forfattere av denne artikkelen] (2026). FROM PEAT TO PONDS: LANDSCAPE HETEROGENEITY DRIVES METABOLIC NETWORKS AND GREENHOUSE GAS RELEASE FROM THAWING PERMAFROST. Fulltekst i vitenarkiv Vis sammendrag

  As permafrost landscapes degrade, they transform into a hydrological mosaic of dry palsas, collapsing thermokarst slumps, and water-saturated ponds. This physical reorganization creates steep gradients in redox potential and organic matter quality, fundamentally altering the thermodynamic constraints on microbial metabolism. We investigated greenhouse gas (CO2, CH4, N2O) production potentials across several permafrost thaw gradients in sub-Arctic peatlands of Northern Norway, linking landscape-scale changes to genome-resolved metabolic networks. By integrating high-resolution metagenomics with organic matter and greenhouse gas production characterization, we found that thaw features act as distinct thermodynamic bioreactors. In water-saturated, anoxic peat layers, oxygen limitation selects for "slow" metabolic guilds specialized in fermentation and methanogenesis while other oxygenated features are constrained by the quality of organic matter—specifically the accumulation of polyphenols and aromatic compounds acts as a metabolic "latch". We show that the shift from oxic to anoxic conditions triggers a non-linear restructuring of the microbial network, where less efficient central metabolism drives high N2O and CH4 yields but suppressed CO2 production. These findings demonstrate that predicting the permafrost-carbon feedback requires mapping the "metabolic landscape"—where organic matter quality and redox thresholds ultimately tune the greenhouse gas release from thawing landscapes to the atmosphere.

• Zaini, Adele; Blichner, Sara Marie; Tang, Jing; Fisher, Rosie; Lund, Marianne T. & Oliviè, Dirk Jan Leo [Vis alle 7 forfattere av denne artikkelen] (2026). Beyond carbon, from Arctic forest migration to climate mitigation: can biogeochemical effects challenge albedo-driven warming? European Geosciences Union General Assembly Abstracts. doi: 10.5194/egusphere-egu26-20671. Fulltekst i vitenarkiv Vis sammendrag

  Rising global temperatures are expected to drive a northward expansion of boreal forests into Arctic regions, triggering multiple and interacting climate feedbacks. This land cover change is also relevant as a parallel to mitigation strategies such as afforestation, which are often evaluated solely for their carbon benefits, while other biogeophysical and biogeochemical effects may substantially offset the intended carbon uptake. Reduced surface albedo from forests replacing snow-covered, treeless areas is widely recognised as a strong warming mechanism. Chemical emissions, specifically biogenic volatile organic compounds (BVOCs), in these regions may also play a substantial role, potentially counteracting albedo-driven warming. In this study, we aim to provide new insights into the climate impacts of Arctic land cover change by assessing both biogeophysical and biogeochemical pathways beyond carbon uptake.BVOCs influence climate through multiple, partly opposing pathways. Their oxidation products contribute directly to secondary organic aerosol formation and modify indirectly cloud optical properties, potentially leading to a cooling effect. At the same time, BVOCs affect atmospheric chemistry by altering the concentrations and lifetimes of key climate forcers such as ozone and methane, which can introduce a positive radiative forcing. The combined effect of these processes, and their relative importance compared to albedo changes, remains uncertain.Here, we use the Norwegian Earth System Model version 2.3 (NorESM2.3), including a newly implemented comprehensive atmospheric chemistry scheme, to investigate the radiative impacts of projected boreal forest expansion. We perform targeted simulations under present-day and warmer climate scenarios, allowing us to isolate the contributions from surface albedo changes, BVOC-driven direct aerosol effects, cloud interactions, and chemistry-related impacts on ozone and methane.By comparing these pathways within a single modelling framework, this work evaluates whether BVOC-related processes can significantly offset albedo-driven warming and how their relative importance evolves under climate warming. The results provide a comprehensive understanding of how land use and land cover changes influence the Arctic climate via interacting biogeophysical and biogeochemical mechanisms.

• Andersen, Gard Lilledal (2026). Kan sosiale medier redde realfagene? Paneldebatt under Arendalsuka. Fulltekst i vitenarkiv
• Andersen, Gard Lilledal (2026). On the rocks: What are the best sauna stones? Panelsamtale under International Sauna Congress. Fulltekst i vitenarkiv
• Andersen, Gard Lilledal (2026). Når isbreene smelter kommer bresorgen. Intervju i Ekko, NRK P2. [Radio]. NRK P2. doi: https:/radio.nrk.no/serie/ekko/IFAK02015326?utm_source=nrkradio&utm_medium=delelenke-web&utm_content=prf%3AIFAK02015326#t=1h18m55s. Fulltekst i vitenarkiv
• Menegon, Luca (2026). Earthquake-induced Damage in the Lower Crust.
• Menegon, Luca; Zertani, Sascha & Lantman, Hugo Willem van Schrojenstein (2026). Transient high stresses during the earthquake cycle in the lower crust and their preservation in the geological record. Fulltekst i vitenarkiv
• Galland, Olivier (2026). Beyond Elasticity – How inelastic properties of crustal rocks control the propagation of dykes and sills in volcanic plumbing systems. Fulltekst i vitenarkiv
• Pinel, Virginie & Galland, Olivier (2026). Limitations of dislocation models for quantifying surface displacement induced by the buoyancy of ascending dikes. doi: https:/meetingorganizer.copernicus.org/EGU26/EGU26-5871.html. Fulltekst i vitenarkiv Vis sammendrag

  Dislocation models, whether analytical or numerical, are widely used to interpret surface displacements induced by magmatic intrusions. Deep learning methods developed for interpreting InSAR data are also trained using synthetic data produced by dislocation models. While these models are well suited to describing the deformation and stresses induced by the emplacement of magma within a planar structure, they neglect buoyancy, which is the main driving mechanism for magma ascent within the crust. We use analog experiments to highlight the effect of buoyancy on dike-induced surface deformation. Finite volumes of air or silicone oil are injected into gelatin, which is characterized by elastic behavior. The fluid-filled crack rises vertically through the gelatin due to buoyancy. Its position, shape, and orientation are tracked by side cameras, and the surface displacement of the gelatin is measured simultaneously by photogrammetry and pixel shift tracking from images acquired by four synchronized cameras located at the top of the experimental setup. We compare the displacement field estimated from the dislocation model with the recorded displacement field in the laboratory. We show that while dislocation models with realistic opening distributions are able to reproduce the displacement field profile fairly accurately, they systematically underestimate vertical displacement in the near field and overestimate horizontal displacements for a buoyant ascending crack. Our study shows that buoyancy of dikes triggers upward displacement of the Earth’s surface, which is not accounted by dislocation models. We discuss in more detail the potential consequences of this bias in dislocation models for the interpretation of geodetic data in volcanic areas.

• Biswas, Uddalak; Galland, Olivier & Carlson, Andreas (2026). Formation of various geometry by viscous magma intruding into visco-elasto-plastic deep crust: a 2D analogue experiment. Fulltekst i vitenarkiv Vis sammendrag

  Magma ascends to the Earth's surface for eruption by traversing the crust, which is the uppermost layer above the mantle, where the magma originates. As this substantial volume of magma moves through the crust, it deforms the crustal rocks, facilitating its progression toward the surface and subsurface. The resulting geometry, which may manifest as thin sheets, branching fingers, or blunt lobes, is set by the competition between the intruding fluid and the mechanical response of the host material. These deformation mechanisms, which control the geometry of the magmatic bodies, are essential for assessing hazards related to volcanic eruptions, seismic activity due to volcanism, and the localisation of economically valuable ore deposits. As the deformation of the crustal rocks by the intruding magma occurs at a certain depth and natural exposures record only the end state of this strongly dynamic process, the mechanics behind this process can’t be inferred directly. To address this gap, researchers have employed analogue modelling as a tool to simulate a simplified analogous intrusion process of magma at a laboratory scale for decades. Conventionally, in these analogue experiments, crustal rocks have been modelled using elastic or plastic Coulomb materials, whereas magma has been represented as a viscous fluid by previous researchers. However, recent studies have shown that deep crustal rocks exhibit a complex visco-elastic to visco-elasto-plastic rheology in nature. To simulate the crustal rocks more accurately, in this study, we approached the problem by injecting a viscous fluid as a magma analogue into an aqueous Laponite® RD (LRD) gel, which acted as a model host rock, confined in a two-dimensional Hele-Shaw cell. The LRD gel exhibits diverse rheological properties, transitioning progressively from a viscous liquid to a viscoelastic state, and ultimately to an elastico-viscous solid, as its curing time (tc) increases. Considering this property of the LRD gel, we used tc = 30, 60, 90, 150, and 240 min to represent crustal rock under different physical and chemical conditions. On the other hand, magma in nature exhibits variable viscosity depending on its composition, temperature and volatile content. In parallel, we varied the injected fluid using water and hydroxyethyl cellulose solutions at 0.50 and 0.75wt%, to span the range of viscosity. Injection was carried out at a fixed volumetric flow rate of 10 ml/min up to a maximum injected volume of 50 ml, so that the flow rate is held constant while the rheology of the host and viscosity of the fluid are varied. Additionally, polyamide tracer particles with a diameter of 60 μm were embedded in the gel, enabling particle image velocimetry (PIV) to simultaneously resolve the deformation field of the host as the intrusion expanded. The experiments produced distinct intrusion geometries that systematically depended on host rheology and the viscosity of the injected fluid. The velocimetry fields from the PIV analysis further show that intrusions of broadly similar shapes can be accommodated by clearly different velocity and strain distributions within the host. Combining the evolving geometry with the accompanying strain pattern therefore offers a route toward identifying which deformation mechanism accommodated a given volume of magma, and this diagnostic can in principle be applied to interpret the intrusion patterns observed in the field.

• Biswas, Uddalak; Galland, Olivier & Carlson, Andreas (2026). Magma emplacement mechanism in visco-elasto-plastic crustal rock: an insight from quantitative 2D analogue experiments. doi: 10.5194/egusphere-egu26-18980. Fulltekst i vitenarkiv Vis sammendrag

  Magma generated at depth ascends through the crust and erupts at the surface. In this process, the magma volume creates space by deforming the crustal rock. To study this process, researchers have employed analogue experiments for decades. Conventionally, most analogue models assume the crustal rock as a purely elastic, brittle (Coulomb), or viscous material. However, natural rocks exhibit more complex visco-elasto-plastic behaviours, with rheological properties transitioning from elastic-plastic to visco-elasto-plastic with increasing depth. Conversely, magma itself behaves as a Newtonian fluid, exhibiting a range of viscosities influenced by factors such as silica and volatile content. In this study, we conducted scaled 2D analogue magma emplacement experiments using Laponite® RD (LRD), a complex visco-elasto-plastic rheological material, as a host rock analogue. The rheological properties of LRD were systematically varied by changing the curing time (tc) from tc = 30 min to tc = 240 min to simulate a broad range of crustal rheological behaviours, corresponding to different depths from viscous to visco-elasto-plastic regimes. Food-coloured water and hydroxyethyl cellulose (HEC) aqueous solutions, with concentrations of 0.50 wt% and 0.75 wt%, are used to simulate magma with varying viscosities. Polyamide seeding particles (PSPs) of 60µm diameter were incorporated inside the LRD solution to quantify host-rock deformation during magma emplacement via particle image velocimetry (PIV). Our experimental results show that magma intrusions exhibit various shapes, ranging from straight-edged fractures in the case of low-viscosity water and viscoelastic LRD of high tc to bulbous, rounded forms in high-viscosity HEC and viscous LRD of low tc. Furthermore, PIV data enabled the identification of domains exhibiting distinct deformation types, thereby delineating changes in deformation regimes attributable to variations in the rheological properties of the host rock. Finally, by integrating geometric and PIV analyses, we established a relationship between the intrusion morphology and host rock rheology, and propose a mechanical model that elucidates the deformation mechanisms operative within the host during magma emplacement across different rheological combinations of host and magma materials.

• Molland, Hedda Susanne (2026). Klimakrisen. I Bolstad, Erik (Red.), Store norske leksikon (snl.no 2026). Store Norske Leksikon (snl.no). doi: https:/snl.no/klimakrisen. Fulltekst i vitenarkiv
• Boon, Annique van der; Boer, Rosa de; Groot, Bertwin de; Nakrem, Hans Arne; Nogueira, Liebert Parreiras & Ruggiu, Lisa Krämer [Vis alle 8 forfattere av denne artikkelen] (2026). A promising novel recorder of Earth’s ancient magnetic field: fossil micrometeorites as paleomagnetic archives. doi: https:/royalsociety.org/science-events-and-lectures/2026/09/unravelling-magnetic-histories/. Fulltekst i vitenarkiv Vis sammendrag

  The paleomagnetic record from sedimentary rocks is often ambiguous, limiting the recovery of reliable paleomagnetic data, particularly when compared to paleomagnetic data obtained from igneous rocks. I will introduce a novel, unexplored recorder of Earth’s magnetic field: fossil micrometeorites. Micrometeorites (MM) are small cosmic particles (50 μm-2mm) that make up a substantial part of the ~40,000 tons of extraterrestrial material delivered to Earth each year. Many MMs melt during atmospheric entry at altitudes of 80-90 km, transforming into cosmic spherules (CS). During this process, particles oxidise and form new minerals, particularly wüstite and magnetite, which record thermoremanent magnetisations upon subsequent cooling. CS are strongly magnetic and can be extracted from sedimentary rocks. Diagnostic features such as metal beads and vesicles inside some CS allow the reconstruction of their flight trajectory, which can be combined with their magnetisations to reconstruct the polarity of Earth’s magnetic field. While modern CS from Antarctica are already known to be robust recorders of the geomagnetic field, their deep-time counterparts remain almost entirely unexplored. I will present the first results of a paleomagnetic study of anthropogenic magnetite spherules that resemble iron-type (I-type) CS, as well as several Paleozoic I-type CS. These 50-300 μm spherules are measurable with standard paleomagnetic tools and, together with flight trajectories obtained using NanoCT scanning, are capable of opening a new window on the ancient geomagnetic field.

• Wang, Yiguo; Bethke, Ingo; Counillon, Francois Stephane; Williams, Nicholas; Nair, Akhilesh & Chiu, Ping-Gin [Vis alle 8 forfattere av denne artikkelen] (2026). Development of NorCPM2 for CMIP7 DCPP: Ocean-Sea ice Initialisation Strategy. Fulltekst i vitenarkiv
• Walsh-Vilander, Anna; Vollsnes, Ane; Berntsen, Terje Koren; Fisher, Rosie & Parmentier, Frans-Jan W. (2026). Quantifying Cold Hardening in Arctic-Boreal Vegetation using Differential Thermal Analysis. Fulltekst i vitenarkiv
• Parmentier, Frans-Jan W. (2026). Can soil carbon content explain inter-site differences in carbon flux magnitude across the permafrost region? . Fulltekst i vitenarkiv
• Parmentier, Frans-Jan W.; Marchesini, Luca Belelli; Wille, Christian; Hugelius, Gustaf; Siewert, Mathias B. & Aurela, Mika [Vis alle 20 forfattere av denne artikkelen] (2026). Can soil carbon content explain inter-site differences in carbon flux magnitude across the permafrost region? doi: 10.5194/egusphere-egu26-14668. Fulltekst i vitenarkiv Vis sammendrag

  The permafrost region holds vast amounts of carbon which, upon thaw, may be released to the atmosphere as CO2 through enhanced decomposition. While links between soil carbon content and respiration have been shown by, for example, numerous incubation studies, it remains challenging to establish similar relationships from in-situ data collected in the field – especially at the large landscape-scale of eddy covariance towers. Part of the reason is the high heterogeneity of Arctic landscapes, combined with frequently shifting footprint distributions, and general lack of detailed soil carbon data that make it difficult to separate the signal from the noise. In this study, therefore, we combine detailed surveys of soil carbon content with high resolution footprint analyses to explore whether inter-site differences in carbon fluxes across ten sites spanning the Arctic can be explained by soil carbon content. Soil carbon data at each site was collected across dominant landforms and analyzed with depth. At 5 sites, these data were further developed into high resolution soil carbon maps. At the remaining sites, spatially weighted estimates of soil carbon content were determined proportionally to dominant landforms. Net CO2 fluxes collected by the towers were processed according to the same pipeline and partitioned into GPP and ecosystem respiration. These fluxes were related to the amount of soil carbon in the active layer at dominant landforms through a spatially explicit footprint analysis. Our preliminary results suggest that active layer soil carbon storage is a strong predictor of inter-site differences in ecosystem respiration during the growing season. This study will further explore the robustness of this relationship across the Arctic and throughout the year.

• Parmentier, Frans-Jan W. (2026). Det sprekker | Klassekampen. Klassekampen. ISSN 0805-3839. s. 3–3. Fulltekst i vitenarkiv Vis sammendrag

  I tundraen på Svalbard spiser klimaendringer seg inn i landskapet.

• Parmentier, Frans-Jan W. (2026). Hodet i sanden | Klassekampen. Klassekampen. ISSN 0805-3839. s. 3–3. Fulltekst i vitenarkiv Vis sammendrag

  Klimapopulisten vil at du skal lukke øynene og tro at det går over av seg selv.

• Parmentier, Frans-Jan W. (2026). Europa smelter | Klassekampen. Klassekampen. ISSN 0805-3839. s. 3–3. Fulltekst i vitenarkiv Vis sammendrag

  Hvor lenge vil vi juble over varmerekorder i Norge?

• Parmentier, Frans-Jan W. (2026). I verste fall | Klassekampen. Klassekampen. ISSN 0805-3839. s. 3–3. Fulltekst i vitenarkiv
• Parmentier, Frans-Jan W. (2026). Ugler i mosen? | Klassekampen. Klassekampen. ISSN 0805-3839. s. 3–3. Fulltekst i vitenarkiv Vis sammendrag

  Våtmarkene holder på mange hemmeligheter – og tusen år gammelt karbon.

• Rosendahl, Andrea; Gjermundsen, Ada; Graff, Lise Seland & Schulz, Michael (2026). Nordic Precipitation Trends and North Atlantic Circulation Patterns in CMIP6 models. doi: 10.5194/egusphere-egu26-10875. Fulltekst i vitenarkiv Vis sammendrag

  Recent observed trends indicate increasing future precipitation in Northern Europe, yet CMIP6 models show substantial spread in sign and magnitude of both historical and future precipitation trends in the region. This large model spread highlights the difficulty in accurately modelling regional precipitation in global climate models, and the low confidence in future precipitation trends. In this study, we evaluate recent historical winter precipitation trends in selected models of the CMIP6 ensemble by validating the models against reanalysis and observations, and examining how the trends are influenced by sea surface temperatures (SSTs) and the large-scale atmospheric circulation, particularly the North Atlantic storm track. We consider data from CMIP6 historical and AMIP experiments, the latter using prescribed observed SST and sea ice concentration. Additionally, we include a complimentary set of AMIP-style experiments with the Norwegian Earth System Model (NorESM2) where we explore the effect of different time-evolving SST fields. Results show that models yield consistent precipitation patterns, which enables an assessment of the role of North Atlantic SST in shaping Nordic precipitation trends, when averaging over multiple ensemble members. Differences in Nordic precipitation trends are tied to differences in the North Atlantic SST pattern evolution, with consistent changes in latent heat flux, atmospheric baroclinicity and lower tropospheric zonal wind patterns. Particularly, differences in SST in the North Atlantic warming hole and along the eastern US coast and close to Svalbard, the latter related to rapid warming from Arctic sea ice loss, can influence the precipitation trends. Employing the relationship between North Atlantic SST and precipitation trends in the Nordic region, we can better understand the large precipitation spread among climate models, and thus increase confidence in both historical and future precipitation in the models. Furthermore, while the majority of CMIP6 models provide just a single ensemble member for the AMIP experiment, our results demonstrate that using multiple ensemble members for the AMIP experiments is essential to account for internal variability and to achieve robust results.

• Silantyeva, Olga & Helset, Sigbjørn (2026). Shyft FSM2 Implementation. doi: https:/gitlab.com/shyft-os/shyft. Fulltekst i vitenarkiv Vis sammendrag

  Shyft is a cross-platform framework built around high-performance time-series storage and analysis, providing the computational foundation for hydrological forecasting and energy-market modelling. The project originated at Statkraft in collaboration with the University of Oslo – Department of Geosciences, and is today used in operational energy-sector environments, including 24×7 systems within Statkraft’s Energy Management division. Shyft combines: - a high-performance C++ core - a Python orchestration layer - scalable compute and cache microservices - enterprise-grade time-series and model storage - model-driven system architecture The framework was created through close interdisciplinary collaboration and continues to enable cooperation between: - domain experts - researchers - software engineers - operational IT teams while maintaining the performance and robustness required for operational energy systems. The SnowSub project contributed to new snow module: https://gitlab.com/shyft-os/shyft/-/tree/master/cpp/shyft/hydrology/methods/snow/fsm2?ref_type=heads and related full hydrological models: PTFSM2K and RPMFSM2K.

• Silantyeva, Olga; Huang, Shaochun & Xu, Chong-Yu (2026). Evaluating flexible process-based hydrological configurations against data-driven benchmarks: a large-sample study across 109 Norwegian catchments. doi: https:/acrobat.adobe.com/id/urn:aaid:sc:EU:15b5965a-cc8b-44c2-ba59-2523cca43137. Fulltekst i vitenarkiv Vis sammendrag

  Large-sample hydrology provides a rigorous basis for assessing model generality across diverse hydro-climatic conditions. We evaluate five configurations of the Shyft flexible modelling framework, varying evapotranspiration (Priestley–Taylor vs. Penman–Monteith), snow (temperature-index snow tiles vs. semi-physical gamma snow), and runoff response (Kirchner vs. HBV routines) across 109 Norwegian catchments spanning mountain, inland, atlantic, baltic, and transient hydrological regimes. Model skill is assessed using KGE and its components, percent bias (PBIAS), KGE on reciprocal flow, and interannual NSE, under ten calibration goal functions. Results are contextualised against the hydroBM benchmark ensemble (Knoben et al., 2024) and an LSTM baseline from the neuralhydrology package (Kratzert et al., 2022). One configuration, containing Penman–Monteith evapotranspiration, temperature-index snow, and Kirchner runoff, performs on par with the LSTM across all metrics. We attribute part of this competitiveness to the Kavetski–Kuczera (2007) smoothing algorithm, which mitigates calibration landscape discontinuities in a manner functionally analogous to gradient-based optimisation in neural network training. This highlights that fair comparison between process-based and data-driven models must account for the full complexity of their respective optimisation problems. The role of precipitation correction in modulating cross-regime performance is also discussed. This study establishes a reproducible baseline for process-based and hybrid model evaluation in the Norwegian context, and lays groundwork for integrating physics-informed constraints into data-driven approaches.

• Silantyeva, Olga; Huang, Shaochun & Xu, Chong-Yu (2026). Benchmarking flexible modelling framework Shyft across mainland Norway. doi: 10.5194/egusphere-egu26-22432. Fulltekst i vitenarkiv Vis sammendrag

  Developing hydrological models, which are process-aware and reliably transferable across diverse environments remains a challenge. We benchmark Shyft – an open-source, fully FAIR (findable, accessible, interoperable and reusable) flexible modeling framework, across 109 catchments in mainland Norway to evaluate how model structure, forcing uncertainty and calibration objective jointly shape streamflow simulation performance. We adopt large sample hydrology perspective to probe five models “stacks”, providing alternative process choices, such as evapotranspiration (Penman-Monteith vs Priestley-Taylor), snowmelt (temperature-index vs semiphysical) and runoff response (Kirchner vs HBV tank and soil) with multiple goal functions drawn from KlingGupta Efficiency (KGE) and Nash-Sutcliffe Efficiency (NSE), with and without catchment specific precipitation correction. We use a suite of evaluation metrics targeting bias, hydrograph dynamics, low flows and interannual variability. We move beyond crude mean-flow benchmarks toward simple climatological benchmarks, providing an objective context for model skill evaluation, given the seasonal nature of Norwegian catchments.The evaluation revealed that configurations containing temperature-index snow simulation and Kirchner runoff offer the greatest robustness and generality across all hydrological regimes. In terms of objective functions, KGEbased targets outperform NSE-based targets, with metric combining KGE and box-cox transformed KGE (KGE_bcKGE) identified as a promising generalist objective, which performs well across diverse metrics, including low-flow targeted (KGE(1/Q)) and interannual NSE. Furthermore, precipitation correction was found to be essential for improving performance in Mountain and Inland regimes, suggesting snow undercatch as a primary source of precipitation uncertainty. Among simple benchmarks, daily mean was found to be best predictor setting model expectations for future model intercomparisons in the region. Our results demonstrate the need for balance of structural adequacy, forcing uncertainty and equifinality.This project is supported by Norwegian Research Council NFR project 336621.

• Ahmed, Nisar; Cardozo, Nestor; Schulte, Lothar; Alaei, Behzad; Oikonomou, D. & Larsen, E. (2026). Deep learning using FCT-network for petrophysical-property estimation from seismic-angle-stacks: 3D application to the Troll Field, North-Sea. Earth Doc, European Association of Geoscientists & Engineers. 2026(1), s. 1–5. doi: 10.3997/2214-4609.202638039. Fulltekst i vitenarkiv Vis sammendrag

  This work presents a deep-learning method using a Fully Convolutional Transformer (FCT)-based encoder--decoder network for direct estimation of the petrophysical properties such as porosity, water saturation, and shale volume from seismic angle stacks and interval velocity. The FCT network integrates convolutional operations within Transformer blocks to map both local seismic features and global geological dependencies. Uncertainty in the estimated models is quantified using Monte Carlo dropout and ensemble predictions, and the framework is validated at training and blind well locations and across a full 3D seismic cube in the Troll Field, yielding accurate and geologically consistent petrophysical property estimates. The predicted properties are further verified through unseen-well validation and their consistency with seismic signatures, fault patterns acting as seal, and reservoir-scale geological features.

• Torsvik, Trond Helge (2026). Apparent polar wander paths and their errors. Fulltekst i vitenarkiv
• Huseynov, Fazil; Kiss, Daniel & Yarushina, Viktoriya M. (2026). Multiphase flow simulations in heterogenous shales. Fulltekst i vitenarkiv
• Fuglestvedt, Herman Fæhn; Fjeldså, Johannes; Sandstad, Marit; Gjermundsen, Ada; Sanderson, Benjamin & Debernard, Jens Boldingh [Vis alle 11 forfattere av denne artikkelen] (2026). Informing tuning of coupled Earth system model NorESM3 with perturbed parameter ensembles. doi: https:/meetingorganizer.copernicus.org/EGU26/EGU26-17495.html. Fulltekst i vitenarkiv Vis sammendrag

  Quantifying parametric uncertainty is important for effective Earth system model development and calibration. Here, we present a 75-member perturbed parameter ensemble (PPE) with the coupled Earth system model NorESM3. As part of operational model calibration, we used the PPE to evaluate parameter sensitivities, identify bias‑reducing parameter choices and trade‑offs, and estimate parametric uncertainty within the model. The PPE was constructed by branching preindustrial (year 1850) simulations from a baseline run, perturbing parameters in the atmosphere, land, ocean, and sea ice modules within expert-informed ranges using Latin hypercube sampling. To study long-term behaviour, we continued a subset of members that met energy-balance criteria while preserving ensemble spread. We evaluated ensemble members against observational and reanalysis datasets to help distinguish biases responsive to parameter tuning from ones likely stemming from model structure.

• Åsmund, Bakketun; Müller, Malte; Blyverket, Jostein & Berntsen, Terje Koren (2026). Improving weather prediction through advanced initialisation and representation of the land surface. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Accurate weather forecasts are important for society through severe weather warnings, power management and general planning. With a changing climate, weather patterns are expected to change with extremes becoming more frequent and more severe. Severe weather impacts living creatures and infrastructure at the surface, making the surface-atmosphere interface crucial for forecasting such events. Numerical weather prediction systems use complex surface models to simulate mass and energy exchanges, but there remains significant potential to enhance surface representation in operational forecasting models. This thesis aims to improve surface conditions in operational weather prediction models. In the first study, the land-atmosphere coupling over the Nordic region is assessed during a high-impact precipitation event. This is done by introducing an alternative initialisation method for the land surface. The study shows the importance of accurate land initialisation for convective precipitation events over the region, which is commonly found to have weak landatmosphere coupling. By introducing more realistic initial conditions for surface variables, the spatial accuracy of heavy rainfall is improved and errors in 2-metre temperature and humidity are reduced. The second study targets the importance of surface conditions in data-driven weather prediction models. This is done by adding more surface descriptors to the model input. This enables the model to account for local effects not captured by the reference model and improves forecasts of near-surface variables. Finally, in the third study, we improve estimates of the seasonal snowpack over the Arctic region by implementing a more advanced method for snow data assimilation. The method distributes snow depth measurements horizontally and vertically within a multi-layer snowpack model, and consistently across state variables. It also enables multivariate assimilation of other surface state variables, which can further increase consistency. In summary, this thesis contributes to operational weather prediction by advancing initialisation methods and the representation of surface conditions within both traditional and data-driven models, showing measurable improvements in forecasts of high-impact and local weather. The findings are particularly important for high-resolution limited area weather forecasting in the Nordic and Arctic regions, which have highly heterogeneous surface conditions, complex topography and seasonal snow cover.

• Bünz, Stefan; Stokke, Henrik Henriksen; Lebedeva-Ivanova, Nina; Sokolkova, Elisaveta; Rohde, Lea & Nygaard, Madeleine Skov [Vis alle 13 forfattere av denne artikkelen] (2026). UiT-IG24-8 Cruise Report Leg 1 High-resolution 2D and 3D seismic investigations on the Vøring Margin. UiT Norges arktiske universitet. Fulltekst i vitenarkiv Vis sammendrag

  This document reports on the acquisition and processing of the seismic, subbottom-profiling and multibeam data acquired during a cruise with UiT the Arctic University of Norway’s research vessel RV Helmer Hansen from 30th July to 15th August 2024. This expedition targeted areas in the northern half of the Vøring Basin and its margin towards the Lofoten Basin, where IODP Expedition 396 drilled at four sites in 2021 (Planke et al., 2023). In addition, we acquired multibeam and water-column data on an extended transit to Ålesund that covered several suspected fluid seepage sites. The seismic acquisition was conducted under the framework of cruise UiT-IG24-8 and NFR funded projects Paleogene Basin Development on the Vøring and Møre Margins (PALMAR, project number 336293) and Permanent sequestration of gigatons of CO2 in continental margin basalt deposits (PERBAS, project number 340832)

• Bünz, Stefan; Polteau, Stephane; Mazzini, Adriano; Binde, Cornelia Mentzoni; Argentino, Claudio & Krueger, Martin [Vis alle 13 forfattere av denne artikkelen] (2026). UiT-IG24-8 Cruise Report Leg 2. UiT Norges arktiske universitet. Fulltekst i vitenarkiv Vis sammendrag

  This document reports on the acquisition and processing of seismic, subbottom-profiling, multibeam, water column data as well as the collection of numerous sediment samples acquired during a cruise with UiT the Arctic University of Norway’s research vessel RV Helmer Hansen from 15-26th August 2024. This expedition targeted an area on the western bank of the Norwegian trench in the northern North Sea, where natural seepage of gas has been identified in 2022. The data acquisition was conducted under the framework of cruise UiT-IG24-8 (Leg 2) and NFR funded project “Understanding Fluid Migration Processes at Offshore Well Site (WELLFATE)

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