Abstract In the flat-bottomed open ocean, the seawater density distribution yields alone the existence of geostrophic baroclinic currents and steric sea-level spatial changes. However, at basin margins, the bathymetry exerts a considerable control on both these quantities. Indeed, the steric sea level vanishes at the coast where depth is zero. Also, continental slopes are vorticity barriers hindering convergence (divergence) of baroclinic transport toward the coast and accumulation (removal) of water there. In the limit of no temporal development, how the coastal sea level is impacted by open-ocean density changes is hence nontrivial and must involve ageostrophic mechanisms. Here, we focus on bottom friction as one such process, provide derivations extending the arrested topographic wave theories to a fully baroclinic ocean, and discuss an application for an eastern boundary margin (representative of the Rockall Slope Current region, for example). We demonstrate that open-ocean density changes yield important joint effect of baroclinicity and relief (JEBAR) along-slope currents, which generate cross-slope Ekman currents due to friction with the seabed. The latter are associated with divergence and convergence leading to sea-level changes above the slope, mediated to the coast via coastally trapped waves. Through this process, not only the coastal sea level is modified but also the along-slope currents are slowed down to well-known asymptotical solutions. Hence, our results link modern theoretical developments in sea-level research and past analytical studies of slope currents. Our effort describes the fundamental notions, and we anticipate it paves the way for more sophisticated works.

Refined late-Pleistocene evolutionary and sea-level history for the Delmarva Peninsula, US Mid-Atlantic Coast

The record of environmental and climatic change through the late Norian stage in paleoequatorial settings has so far received limited attention. Here we present new geochemical and sedimentological data to investigate the depositional and environmental changes through the late Norian into the earliest Rhaetian in the marine carbonate Milaha and Ghalilah Formation exposed in Wadi Milaha, Ras Al-Khaimah, UAE. The upper part of the Milaha Formation studied in Wadi Milaha, comprises sediments deposited in a shallow marine environment, with some evidence of high-energy shoal deposition. Restricted conditions are present in the basal and middle part of the Asfal member of the Ghalilah formation, followed by high diversity faunal content, indicating the development of open marine conditions in the late Norian-early Rhaetian. Development of the restricted conditions upwards suggests changes in the relative sea level. Our results show that the succession is comprised of regressive-transgressive cycles, which include minor depositional cycles influenced by changes in clastic input. Sedimentological and elemental data indicate fluctuations in clastic input throughout the sedimentary succession studied. The increase in siliciclastic input coincides with a major regressive sea level cycle during the middle-late Norian. Our results suggest that the increased coarse terrigenous input is likely due to enhanced weathering and an associated warming episode during the late Norian. Very low correlation of δ 13 C carb and δ 18 O indicates little diagenetic influence on the isotopic record. The δ 13 C carb records an overall negative trend during the middle-late Norian with small-scale fluctuations of −2.8‰ magnitude and coincides with increased clastic input. A small positive excursion in δ 13 C carb is recorded at the Norian-Rhaetian boundary. The observed variations in sedimentary succession, relative sea level, and bulk carbonate carbon isotopic record are similar to those of other Tethyan sections. This comprehensive and comparably high-resolution record very likely indicates far-reaching or global ecological changes during the middle-late Norian. • Study area occupied a paleo-equatorial position during the mid-late Norian • Sedimentological investigations allowed the interpretation of sea level cycles • Enhanced siliciclastic input suggest intensification of hydrological cycle • Comparison of the carbon isotope trends suggests ecological changes in late Norian

• The study improves CCSM4′s climate component processes modeling. • CCSM4 enhances accuracy of global phenomena and regional climate variability simulations. • The model validation ensures the reliability for future climate projection studies. • CCSM4 aids climate assessments via insights into anthropogenic climate change. • The world’s largest archipelago in tropics, vulnerable to sea level rise disasters. Climate change and steric variables influence sea level rise in the modern era. This study used the Community Climate System Model version 4 (CCSM4) to compare sea surface temperature (SST) and sea level height (SSH) in Indonesia during the mid-Holocene (MH), pre-industrial (PI), and future periods in 2300 with Representative Concentration Pathways 8.5 (RCP8.5). The results show that the average SST value is lower in the MH, with a change in values of around −1°C in the MAM season and increases in the future by around 2°C, whereas the average SSH value is lower in the MH with a change in values of around −0.1 m during the SON season in Western Sumatra and increases in the future over the SON season by around 0.1 m in Northern Papua, compared to PI. The average correlation between the two metrics is positive, with values of 0.55 (MH-PI) and 0.8 (RCP8.5-PI). SST and SSH climatological patterns in Western Sumatra, the Banda Sea, and Northern Papua reveal that SST and SSH fall during the JJA season and increase during the SON season, respectively. This fluctuation is produced by either a lag in insolation or the winter remnant effect. Signal analysis with Fourier transform reveals that the major signal spectrum for changes in SST and SSH is contributed by annual and semi-annual periodicity in the three regions. A notable interannual periodicity exists; however, it is not predominant, leading to variable interannual influences on SST and SSH in Indonesia.

Unraveling the Piton de la Fournaise eastern flank structure by reconciling data from multiple geophysical methods

Understanding future shoreline evolution is fundamental to developing adaptive coastal management strategies under climate change scenarios. This study analyzes the Southern Baltic Sea’s ∼37-km stretch comprising Usedom and Wolin islands, where sandy coastlines face intensifying erosion threats under rising anthropogenic and climatic pressures. We introduce an explainable Long Short-Term Memory Recurrent Neural Network (LSTM-RNN) framework designed to bridge the gap between Deep Learning (DL) performance and physical interpretability in decadal forecasting. The results show that the best model achieves a Root Mean Squared Error (RMSE) of 10.40 m, Mean Absolute Error (MAE) of 7.13 m, and R-squared (R 2 ) of 0.55. Deep SHapley Additive exPlanation (DeepSHAP) attribution reveals that erosion is driven by the compound interaction of sea-level rise (SLR), storm surges, and extreme waves. This transferable framework represents a significant methodological contribution, enhancing regional early-warning systems and providing a robust, "white-box" approach for Baltic Sea’s operational coastal management. • A sequence-aware neural network model forecasts decadal shoreline change until 2050. • The best model achieves an R-squared value of 0.55 for decadal shoreline change. • Explainable models show erosion is driven by sea levels and extreme waves. • Widespread erosion intensification is projected for the Southern Baltic by 2050.

At high elevations, tree saplings and shrubs are usually protected by mid-winter snow cover, although climate change is expected to extend the snow-free (SF) period. Exposure to winter drought, freeze-thaw events and freezing temperatures will therefore increase, inducing damages to the hydraulic system and to living cells, resulting in reduced growth and increased mortality. A snow removal experiment was carried out at 1700 m. above sea level on saplings of five different species (Acer pseudoplatanus, Juniperus communis, Larix decidua, Picea abies and Sorbus aucuparia). Stem diameter was continuously monitored and compared with spring hydraulic conductivity (PLCspring), living cell mortality (PLDspring), nonstructural carbohydrates (NSCs), growth and survival rates. Under SF conditions, saplings had higher PLCspring and higher PLDspring, and thus experienced greater winter dehydration, resulting in lower growth compared with snow-covered saplings. Summer mortality was strongly correlated with PLCspring and PLDspring. These two key ecophysiological parameters predicted the risk of mortality in all species, whereas only PLDspring reduced growth. By monitoring stem diameter during winter, we have defined indices to quantify resistance and recovery of woody plants under increased frost pressure. Recovery strategies such as resprouting or embolism repair were critical for survival, highlighting the potential vulnerability of saplings to climate change at high elevations.

Hydrodynamics of Mar Menor through field observations and numerical modeling: A wind-forced coastal lagoon

Global oxygen distributions at the Earth's surface.

The late Oligocene to Early Miocene marked a critical phase in Earth's climate history characterized by the onset and evolution of the Icehouse climate mode, following the Antarctic glaciation at the Eocene-Oligocene transition. During this interval, the Antarctic ice volume fluctuated, driving global sea-level changes and reorganizing oceanic circulation. These changes are recorded by several glacial maxima, including the prominent Mi-1 event, which is associated with deep-sea cooling, sea level fall, and a major reorganization of the global carbon and nutrient cycles. The Early Miocene Carbon Maximum (EMCM) reflects enhanced primary productivity triggered by intensified ocean circulation and increased weathering. Meanwhile, the global carbon cycle became increasingly responsive to astronomic forcing, particularly eccentricity cycles. The phosphorus biogeochemical cycle also reorganized, with phosphogenesis events documented in both the Atlantic and Pacific oceans. This study investigates the Oligocene–Miocene interval in the Central Mediterranean, focusing on the largely investigated phosphatic layers of Southeastern Sicily (Hyblean Plateau). Through integrated calcareous plankton biostratigraphy and Strontium Isotope Stratigraphy, three main hiatuses are identified, corresponding to glacial events (Oi-2d, Mi-1, Mi-1a, Mi-1aa, and Mi-2). These hiatuses are locally associated with condensed, phosphate-rich layers linked to the upwelling of nutrient-rich waters and sea level fall. The occurrence and distribution of these layers highlight the Mediterranean's sensitivity to global climatic and biogeochemical shifts during the early Icehouse mode. This work provides new stratigraphic constraints and paleoceanographic interpretations, highlighting how glacial dynamics, ocean circulation, and regional tectonics influenced nutrient availability, phosphogenesis and sedimentary facies distribution during the Oligocene–Miocene. • Biostratigraphy and SIS identify two hiatuses marked by phosphate-rich hardgounds. • Phosphatic layers correlate with global oxygen positive spikes and glacial maxima. • Phosphate-rich layers formed by nutrient-rich upwelling currents. • Icehouse Climate sustained high nutrients, efficient circulation and upwelling.

The past ∼ 50,000 years encompass a series of major climatic transitions, including Marine Isotope Stage 2, the Marine Isotope Stage 2/1 transition, and the onset of the Holocene, when the Earth underwent large shifts in temperature, ice volumes, sea levels and atmospheric circulation patterns. There is a growing body of research focused on the behaviour of the Indo-Australian Summer Monsoon (IASM) during these periods from sites close to Australia’s northern coastlines and currently within the zone of direct monsoon precipitation. However, the relative contributions of latitudinal shifts and/or moisture carrying capacity of the monsoon system on changes in hydroclimate remain uncertain. Here, we present the results from a 46,000-year sediment record obtained at the modern southern extent of rainfall penetration into north-west Australia associated with the IASM. Our results show that the region experienced reduced precipitation until the end of the glacial. During the MIS 2/1 transition and the early Holocene, there is evidence of an increase in wet-season precipitation, likely limited to extreme events occasionally reaching the site. More pronounced and sustained shifts in precipitation were limited to the late Holocene, during which the variability recorded at the site aligned with that interpreted from records further to the north in Australia. We interpret this as reflecting a time-transgressive southward shift in the southern limit of the monsoon system. • Inland monsoonal Australia (18.5°S) experienced a dry and stable late MIS 3 and MIS 2. • Following MIS 2, conditions became wetter towards the present day. • Apart from brief, high-intensity events, the IASM did not consistently influence the interior (18.5 °S) during the MIS 2/1 transition and early Holocene. • By the late Holocene, precipitation patterns in the inland eastern Kimberley were in phase with those indicated by previous records located further north.

X-band radar images of ocean waves offer a promising approach to estimate vertical current shear near the ocean surface, a region where direct measurement remains challenging. Inversion techniques on wavelength-dependent Doppler shifts have been used previously. However, they were restricted to a few meters below the sea surface. This study uses a smoothing technique along with in-situ measurements at lower depths to infer the current profile up to the mean sea level ( z = 0 m), thus delivering a measure for vertical current shear, an important indicator for the air-sea energy transfer. The method was applied to radar images collected during a storm event where concurrent measurements of an ADCP were available. The method also performs well without the use of in-situ measurements at lower depths, though accuracy improves when such data is available to stabilize the solution. This study has used shear as an overall measure of energy transfer of the wind into the water. Hence, a comparison of the extracted shear magnitude with the wind speeds at 10 m above sea level has been conducted. The shear magnitude increases are mirrored by the wind speeds. These promising results display that the study is a proof-of-concept study which requires future investigation. • Retrieval of current profile with the boundary layer just underneath the sea surface. • Current inversion from X-band radar images. • Improved results by incorporating in-situ measurements at lower depths. • Magnitude and direction of extracted shear follow pattern of wind measurements.

Holocene sea–level changes and fluvial controls on the geomorphic evolution of the Thalassery river mouth, southwest Kerala coast, India

SeaQC-X: Transferability of a machine learning-based sea level quality control framework

• STGAT model is developed to reconstruct high-resolution subsurface Temperature from satellites. • Multi-source satellite data and DSTAG enable high-accuracy reconstruction of ocean subsurface temperatures. • Joint training on reanalysis and EN4 data enhances subsurface temperature fidelity. The distribution and variation of ocean temperature are closely associated with ocean dynamic processes. High-precision ocean subsurface temperature fields are critical for studies on ocean dynamics and climate change. While satellite remote sensing provides extensive data on sea surface temperature, it lacks direct observations of ocean subsurface temperatures. In-situ measurements typically result in sparse and uneven spatiotemporal data coverage. Consequently, obtaining accurate high-resolution ocean subsurface temperature data remains a significant challenge in marine science. This study introduces a novel ocean subsurface temperature reconstruction model based on Spatiotemporal Graph Attention Networks (STGAT). STGAT is capable of inferring subsurface temperature fields from multiple satellite-derived sea surface observations, including Sea Level Anomaly (SLA), Sea Surface Temperature (SST), Sea Surface Salinity (SSS) and Sea Surface Wind (SSW), as well as the derived Depth-Specific Temperature Anomaly Gradient (DSTAG). The Kuroshio Extension region in the Northwest Pacific, characterized by intense ocean dynamic activity, was selected as the experimental area. Ocean temperature fields at 21 depth levels (20–1941 m) for 2022 were reconstructed using satellite sea surface observations from 2017 to 2022. The accuracy of the reconstructed subsurface temperature fields was evaluated using the GLORYS12V1 reanalysis datasets and the EN4 in-situ observation datasets. Comparative analysis with reanalysis data demonstrates that the proposed model effectively captures the spatiotemporal characteristics of ocean temperature across all depth levels, accurately reflecting realistic spatial distributions throughout the water column. The reconstructed subsurface temperature fields achieved mean RMSE and R 2 values of 0.916 °C and 0.866, respectively. Validation against EN4 data further confirms that the model’s ability to reproduce vertical thermal variations, with mean RMSE and R 2 values of 0.898 °C and 0.976, respectively. When compared with other machine learning-derived models, the STGAT model demonstrates superior performance in terms of reconstruction accuracy. In conclusion, the STGAT model effectively addresses the challenges posed by complex and highly turbulent oceanic processes, offering a promising new approach for retrieving high-resolution and high-accuracy ocean subsurface temperature data.

Current and projected impacts of climate change on Arabian Gulf sea level rise

Predicting blue carbon sequestration in Sundarban coastal mangroves: A spatially explicit approach with INVEST and machine learning to advance climate resilience and UN SDG-aligned nature-based climate solutions.

Creating quantitative tools to assess scenarios of impacts of geological processes (such as landslides, subsidence, volcanic eruptions, earthquakes), often chained in a “domino-like” effect, is an ambitious goal for quantifying risk and, consequently, supporting effective mitigation and resilience planning. The RETURN Project, funded by the Italian National Recovery and Resilience Plan (PNRR), integrated multidisciplinary expertise to generate such scenarios and demonstrate their feasibility through a Virtual Test Bed (VTB). The need to create this virtual demonstration environment arises from the complexity of the cause-effect relationship in natural processes while enabling the evaluation of influencing factors and parameters through scalable and territorially transposable approaches. To this end, RETURNLAND was designed as a digital space composed a complex mosaic of territorial elements extracted from the Italian surface and broadly representative of physiographic units and the geological processes active within them. RETURNLAND was used to activate tool chains capable of producing irreversible effects on the ground surface and in the submarine environment (within the near shore), which can be addressed, through impact chains, to damage infrastructure, urban areas, and communities. Among these chains, landslide-induced tsunami and consequent coastal flooding, ash-fall and ignimbrite flow propagation, subsidence and sinkholes related to sea level rising are here presented. RETURNLAND, with its virtual space, represents part of a larger Proof of Concept of the RETURN project which, among others, includes, with the same meaning as VTB, urban realities (defined as RETURNVILLEs) and human communities.

Abstract. The North Atlantic region is a key component of the climate system via large-scale atmosphere and ocean circulation. Climate field reconstructions can provide a long-term context for ongoing climate change and contribute to our understanding of climate dynamics, impact of external forcings, and act as references for model evaluation and baseline for natural variability. There are distinct differences in North Atlantic climate variability between the seasons in terms of climate modes and amplitude of the variance. Constraining long-term climate variability in sub-annual resolution is therefore needed for a more complete understanding of the governing processes. In this study, we present reconstructed climate in annual and seasonal resolution based on a small high-quality network of proxy data combined with output from an isotope enabled climate model. Compared to earlier work, we have improved the methodology to obtain better skill across a larger area and more realistic variance of the reconstructed variables which include 2 m temperature (T2m), sea surface temperature (SST), sea level pressure (SLP) and precipitation amount. Here we validate the reconstructions against reanalysis data, observed SST and eight long-term records of observed temperature. The reconstructed temperature correlates with up to 0.71 for seasonal data and 0.68 for annual data compared to reanalysis data. The skill for SLP shows the imprint of large-scale circulation for winter with more local patterns dominating for summer. This is also mirrored in the skill for precipitation. In addition, the reconstructed annual mean SST shows basin-wide skill for the North Atlantic, indicating relevance of the reconstruction to studies of atmosphere-ocean interaction. A comparison to other climate field reconstructions show that our new reconstruction has comparable properties, and is unique in offering long-term seasonal SLP, temperature and precipitation. This comparison also underlines the importance of consistency in choice of assimilated proxy data, which influences the long-term performance of the reconstruction. In summary, the results show the potential of assimilating a small high-quality network of proxy records.

Abstract. Coastal flooding is among the most damaging natural hazards in Europe, yet large-scale assessments have typically relied on simplified static “bathtub” models and coarse elevation data. Here, we present a novel pan-European methodology that applies a dynamic flood model at 25 m resolution, forced by location-specific total water level hydrographs. These hydrographs integrate mean sea level, tides, storm surge, and wave setup with spatially varying foreshore slopes, allowing storm type, duration, and shape to be explicitly represented. More than 51 000 coastal target points were used to reconstruct events, and the methodology was validated against 12 local-scale historical floods across diverse coastlines. The validation results confirmed the robustness of the large-scale methodology while highlighting the strong dependence of the results on the resolution and vertical accuracy of the underlying digital elevation model. At continental-scale, sensitivity analyses quantified uncertainty from model selection, hydrograph shape, and storm type. Results show that static flood models systematically overestimate inundation, with errors exceeding 25 % in low-lying coastal floodplains such as Belgium and the United Kingdom. At the continental scale, storm type variability explains 41 % of flood map uncertainty, while hydrograph shape has a smaller but measurable effect. Including coastal protection standards reduces the estimated exposed floodplain by more than half, underscoring the critical role of defenses. By bridging the gap between global static assessments and local dynamic models, this study establishes a methodological benchmark for continental-scale flood hazard mapping.