bluuebunny/crossref_metadata_2025 huggingface dataset:
Unraveling the early South Atlantic records: in situ 87Sr/86Sr isotopic analysis in Aptian carbonates from the conjugated margins of Brazil and Angola.
Authors: Cury Leonardo , Sato Kei , Micheletto Joicy , Santos Larissa , Amthor Joachim , Bahniuk Anelize
Published: March 2024

The 87Sr/86Sr ratio stands as a crucial isotopic marker for the paleogeographic and paleoenvironmental reconstruction of Aptian carbonate sequences in the offshore Campos and Santos basins in Brazil, as well as the Namibe basin in Angola. It facilitates the identification of distinct stratigraphic successions and alterations in the basin's source areas, allowing for valuable geological correlations and interpretations on both margins. Furthermore, it can indicate diagenetic processes, hydrothermal events involving chemical mobility, and textural modifications associated with regional tectonic events linked to the evolution of the South Atlantic rift.
In isotopic dilution analyses, the quality of the results is ensured by eliminating interferences and ensuring a stable signal during spectrometric reading, where the 87Sr/86Sr ratios have analytical precision between the 5th and 6th decimal place. However, samples with a significant compositional variation, such as laminations, microstructures, microveins, or even with clastic minerals, may yield scrambled distinct signals during the grinding and homogenization processes, making it difficult to recognize subtle variations. Strontium isotope analyses by laser ablation coupled to multi-collector ICP-MS Neptune Plus, obtained through the in situ 87Sr/86Sr method have great potential and broad applicability in cases where the search for gentle isotopic signal variations is relevant, such as in the study of drilling cores. By using integrated petrographic information, it has become possible to perform high-resolution analyses, addressing different components of the crystalline system, with strontium intensities ranging from 200 mg/L to ~ 6000 mg/L. The speed of the analyses, from sampling rock fragments to performing laser-based analyses, provides a large volume of results in a relatively short period of time, facilitating correlations between stratigraphic intervals.
The in situ 87Sr/86Sr method has analytical precision between the 4th and 5th decimal place, with sufficient sensitivity to characterize different groups defined by ratios in the ranges of 0.712 - 0.714 (predominantly continental), 0.710 - 0.711 (mixed), and 0.709 - 0.710 (marine influence). Its application in the study of pre-salt carbonates brings a significant advancement in recognizing the environment, and its genetic and diagenetic processes, with great potential to advance our understanding of chemostratigraphy and unravel the transition between continental and marine environments in the early stages of the South Atlantic Ocean's history.
How could a single Iceland Plume produce the widely scattered North Atlantic Igneous Province volcanism? New clues from Britain and Ireland.
Authors: Bonadio Raffaele , Lebedev Sergei , Chew David , Xu Yihe , Fullea Javier
Published: March 2024

The extensive Paleocene magmatism of the British and Irish Tertiary Igneous Province (BITIP)—a part of the North Atlantic Igneous Province (NAIP)—was accompanied by significant uplift and exhumation, as evidenced by geothermochronological and other data. The enigmatic origins of the volcanism and uplift are debated. The Iceland Hotspot reached the North Atlantic at that time and could probably supply anomalously hot asthenospheric material to the volcanic areas of NAIP, but they were scattered over a broad area thousands of kilometres across. This motivates alternative, non-plume explanations.Here, we obtain a map of the lithosphere-asthenosphere boundary (LAB) depth in the region using thermodynamic inversion of seismic surface-wave data. Love and Rayleigh phase velocity maps in broad period ranges were computed using optimal resolution tomography with direct model error estimation and supplied the data for the inversion.Our results reveal a consistently thinner-than-average lithosphere beneath the Irish Sea and surroundings, encompassing northern Ireland and western Scotland and Wales. The Paleocene uplift, BITIP volcanism and crustal underplating are all located in the same regions, which are underlain, consistently, by anomalously thin lithosphere.The previously unknown lithospheric anomalies we discover yield a new insight into how the Iceland Plume could cause volcanism scattered over the vast NAIP. Plume material is likely to have flowed into pre-existing areas of thin continental lithosphere, whose thickness was then reduced further by the erosion by the hot asthenosphere. The thinning of the lithosphere and the presence of hot asthenosphere beneath it can account for the uplift, volcanism and crustal underplating. The localisation of the plume material in scattered thin-lithosphere areas, such as the circum-Irish-Sea region, can explain the wide scatter of the volcanic fields of NAIP.
Benefits of PRISMA hyperspectral data for tree species classification in an area of high forest biodiversity
Authors: Delogu Gabriele , Caputi Eros , Perretta Miriam , Patriarca Alessio , Ripa Maria Nicolina , Boccia Lorenzo
Published: March 2024

The Serre Regional Park in the south of Italy (lat. 38.55, long. 16.35) extends over an area of 17900 hectares, largely covered by forests with a high level of biodiversity. The forest cover is mainly composed of about 15 tree species. This type of area is a natural laboratory for experimenting with forest classification techniques. Indeed, this work aimed to test how to use remote sensing (RS) hyperspectral data combined with innovative AI-based classification techniques to classify forest tree species. The potential of RS for monitoring agricultural and forestry conditions is enhanced by the wealth of information provided by hyperspectral imagery (HSI) and new classification techniques. HSI derived from recent satellite missions (e.g. PRISMA or EnMAP) provides information in multiple bands, from visible/near infrared (400-1010nm) to shortwave infrared (920-2505nm). In addition, the last decade has seen renewed interest in Deep Learning (DL) methods. In particular, convolutional neural networks (CNN) have been widely used in the analysis of images.The study area includes the Park and corresponds to an acquisition of 900 km2 of the PRISMA satellite (taken in July 2023). The PRISMA L2D level cube (Cube 1) used in this study was first processed, for format conversion and georeferencing improvement of the image, with a Python script developed by the authors (www.github.com/LarpUnina/PrismaTool). Next, two different techniques were used to reduce the dimensionality. A second cube (Cube 2) was obtained using a band selection operation and a third cube (Cube 3) was obtained using a PCA technique. For the next classification step, both cubes were used as input. Specifically, a Convolutional Neural Network was selected to classify the data using the open source AVHYAS plugin in the Qgis environment. Ground truths were derived from four SAC site plans provided by the Park Authority, covering approximately 9000 hectares, and were split (70 - 30 %) both to train the network and to test the results. The classes chosen for the classification task includes the most common tree species in the Park area: chestnut (Castanea sativa), larch pine (Pinus nigra), alder (Alnus glutinosa), beech (Fagus sylvatica), silver fir (Abies alba), oak (Quercus ilex) and poplar (Populus alba).  Cube 2 gave better results than Cube 3 as input data with an OA higher than 90%. The best results with F1 around 90% among tree species were obtained for Fagus sylvatica, Abies alba and Castanea sativa. Populus alba was the species with less accurate results. HSI contributes to a better definition of the trends of the spectral signature of trees and makes it possible to distinguish even between similar species.
ClarifAI: Interactive XAI Methods for Geosciences
Authors: Grushetskaya Yulia , Sips Mike , Schachtschneider Reyko , Saberioon Mohammadmehdi
Published: March 2024

In geosciences, machine learning (ML) has become essential for solving complex problems, such as predicting natural disasters or analysing the impact of extreme temperatures on mortality rates. However, the integration of ML into geoscience scenarios faces significant challenges, especially in explaining the influence of hyperparameters (HP) on model performance and model behaviour in specific scenarios. The Explainable Artificial Intelligence (XAI) system ClarifAI developed at GFZ addresses these challenges by combining XAI concepts with interactive visualisation. ClarifAI currently provides users with two interactive XAI methods: HyperParameter Explorer (HPExplorer) and Hypothetical Scenario Explorer (HSExplorer). HPExplorer allows interactive exploration of the HP space by computing an interactive tour through stable regions of the HP space. We define a stable region in HP space as a subspace of HP space in which ML models show similar model performance. We also employ HP importance analysis to deepen the understanding of the impact of separate HPs on model performance.The Hypothetical Scenarios Explorer (HSExplorer) helps users explore model behaviour by allowing them to test how changes in input data affect the model's response. In our presentation, we will demonstrate how HSExplorer helps users understand the impact of individual HPs on model performance. As ClarifAI is an important research area in our lab, we are interested in discussing relevant XAI challenges with the XAI community in ESSI. Our goal is to create a comprehensive set of tools that explain the mechanics of ML models and allow practitioners to apply ML to a wide range of geoscience applications.
Wind tunnel study on the influence of vegetation density and wind direction on urban canyon ventilation
Authors: Del Ponte Annika Vittoria , Fellini Sofia , Marro Massimo , Salizzoni Pietro , Ridolfi Luca
Published: March 2024

Inserting vegetation within the urban environment mitigates the urban heat island effect, the flooding risk, and improves air quality. However, its aerodynamic effect has remarkable impact on the pollutant transport and, consequently, on human health comfort. Indeed, the presence of vegetation within an urban canyon leads to non-trivial patterns of pollutant concentration and mass fluxes, as a consequence of complex mean and turbulent velocity fields. In addition to the vegetation density, the flow structure within canyons is influenced by their geometry and by the wind direction.   The aim of the present study is to experimentally investigate the velocity field within a canyon, varying the vegetation density and the wind direction. We measured flow velocity statistics within an indefinitely long street canyon, with unit height-to-width ratio, subject to a neutrally stratified boundary layer modeled in the wind tunnel of École Centrale de Lyon. The aerodynamic impact of vegetation was reproduced by inserting plastic miniatures of trees along the two long sides of the canyon. We considered an empty canyon and a vegetated canyon, whose longitudinal axes are oriented with angles of 0°, 30°, and 60° with respect to the external wind flow.  Results reveal that when the canyon is inclined with respect to the external wind direction the mean flow follows a complex helicoidal structure. The presence of trees decreases significantly the mean longitudinal velocity and weakens the transversal circulation in the inclined canyon. The dampening effect of the mean longitudinal flow is more marked increasing the inclination angle of the canyon. Turbulent fluctuations are enhanced above the tree crowns, mostly when the wind blows parallel to the canyon axis. On the contrary, turbulent fluctuations decreases at tree trunk and crown levels, in particular when the canyon is inclined of 60° with respect to the external wind direction. Spectra of the velocity signal show that the presence of trees induces an evident shift of the energy peak towards high frequencies.  The collected data constitute a step forward to understand and modeling the urban microclimate.
A Paleoenvironmental record from Lake Gosainkunda, Nepal
Authors: Acharya Sudip , Rana Darwin , Prochnow Maximilian , Dulias Katharina , Dawadi Binod , Schwalb Antje , Zech Roland
Published: March 2024

The Himalayan region is a key area for climate and environmental change and has experienced rapid and pronounced changes over the past decades. Paleoenvironmental studies from this region are crucial to understand natural climate variability. Here we investigate a ~150 cm long sediment core, spanning over the last ~7 cal. ka BP, from a small high-altitude Lake Gosainkunda (surface area ~2.3 km2, 4300 m elevation) in the central Himalayas using a multiproxy approach. Several maxima in allochthonous elements such as Ti and K, sand, as well as white layers indicate increased erosion, possibly related to flood events. Low input of allochthonous elements and sand from ~7 to 6 cal. ka BP, and from ~5 to 1.8 cal. ka BP implies reduced erosion interpreted to be associated with low precipitation. Contemporaneously, high values of log(Si/Ti), log(Ca/Ti), BSi, and inc/coh indicate high aquatic productivity, mainly controlled by higher growing season temperature and shorter duration of ice cover. High allochthonous and sand input from ~6 to 5 cal. ka BP and from ~1.8 to 1 cal. ka BP indicate increased erosion related to high precipitation. Concurrently, low aquatic productivity and authigenic carbonate production as well as positive excursion in bulk δ13C and δ15N values suggest reduced growing season temperatures and longer ice-cover. In the last ~1 ka, increased allochthonous input is related to increased anthropogenic activity in the catchment. We are now aiming to apply a suite of lipid biomarkers including the compound-specific hydrogen isotopic composition of n-alkanes for paleohydrological reconstruction as well as polycyclic aromatic hydrocarbons and faecal biomarkers to investigate paleo-fires and human impacts.
Mapping Phosphorus Forms in the Pan-Amazon Region: A Machine Learning Approach
Authors: Darela-Filho Joao Paulo , Rammig Anja , Fleischer Katrin , Reichert Tatiana , Lugli Laynara F. , Quesada Carlos A. , Hurtarte Luis Carlos C. , de Paula Mateus D. , Lapola David M.
Published: March 2024

Phosphorus (P) is a key driver of terrestrial productivity. However, the lack of spatial data on various P forms in soils hinders the large-scale application of process-based vegetation models. To address this, we used a model selection approach based on Random Forest regression models to predict different P forms (total, available, organic, inorganic, and occluded P) in the pan-Amazon region. Our models were trained and tested using data from 108 sites of the RAINFOR network, including soil group and textural properties, geolocation, nitrogen (N) and carbon (C) contents, terrain elevation and slope, soil pH, and mean annual precipitation and temperature. The models were then applied to several spatially explicit datasets to predict the target P forms. The resulting maps depict the distribution of total, available, organic, inorganic, and occluded P forms in the topsoil profile (0 - 30 cm) at a spatial resolution of 5 arcminutes. Our models achieved a good level of mean accuracy (77.37 %, 76,86 %, 75.14 %, 68.23 %, and 64.62% for the total, available, organic, inorganic, and occluded P forms, respectively). Our results reveal a clear gradient of soil development and nutrient content, with the mapped area generally exhibiting very low total P concentration status. Total N was the most important variable for predicting all target P forms. Despite some gaps in the training and testing data, most of the area could be mapped with a good level of accuracy. Our maps can aid in the parametrization and evaluation of process-based terrestrial ecosystem models and promote the testing of new hypotheses about P availability and soil-vegetation feedbacks in the pan-Amazon region.
February 2023 Mw 7.8 Pazarcık (Kahramanmaraş) Earthquake: the rupture geometry and slip distribution
Authors: Zabcı Cengiz , Kıray Havva , Akyüz H. Serdar , Sançar Taylan , Akçiz Sinan O. , Uçarkuş Gülsen , Kırkan Erdem , Sunal Gürsel , Aksoy M. Ersen , Battogtokh Davaasambuu , Yakupoğlu Nurettin , Köküm Mehmet , Balkaya Musa , Sabuncu Asen
Published: March 2024

February 2023 Mw 7.8 Pazarcık (Kahramanmaraş) Earthquake generated about a 300 km-long surface rupture between the Antakya airport to the south and the Karaköse and Yarpuzlu villages (Sincik, Adıyaman) to the north and strong ground motions, resulting in extensive property damage and loss of lives. We rapidly started to document the deformation structures on the surface by the second day of the event, spreading into smaller mapping teams and covering nearly the entire rupture zone. In addition to walking the rupture and recording locations with GPS waypoints, we made surface offset measurements with a standard tape measure. We used several sUAS’ to acquire high-resolution Digital Orthophoto Maps and Digital Surface Models (between 3 to 5 cm pixel resolution) to map the coseismic slip and surface rupture zone details. We utilized high resolution stereo aerial images with 10 or 30 cm ground pixel resolution, collected by the General Directorate of Mapping, in areas where we could not collect high-quality sUAS imagery.This poster presentation aims to show the full extent of our field and sUAS-based rupture map and horizontal slip measurements of the Pazarcık Earthquake. At the most southern section, the rupture along the Hatay Rift is ~115 km long with a maximum sinistral offset of about 4.5 m between Nurdağ and Şekeroba towns. Between Türkoğlu and Gölbaşı, the rupture is 85 km long and the maximum slip reaches up to ~7m to the north of the Pazarcık town, close to the junction of the East Anatolian and Narlı faults. Farther to the NE, between Gölbaşı and Çelikhan, the slip first decreases to a mean value of ~2.5 m, but then it increases again to ~6.5 m at Kurucaova village. This section of the fault zone is nearly one km wide and is characterized by numerous sub-parallel surface breaks. To the north east of Çelikhan, the slip drops to less than one meter. It diminishes to the north of the Karaköse village (Sincik, Adıyaman), leaving of about 20 km-long unbroken fault section at the surface until the southwest termination of the 2020 Mw 6.8 Sivrice Earthquake rupture.
Downscaling with the foundation model AtmoRep
Authors: Langguth Michael , Lessig Christian , Schultz Martin , Luise Ilaria
Published: March 2024

In recent years, deep neural networks (DNN) to enhance the resolution of meteorological data, known as statistical downscaling, have surpassed classical statistical methods that have been developed previously with respect to several validation metrics. The prevailing approach for DNN downscaling is to train deep learning models in an end-to-end manner. However, foundation models trained on very large datasets in a self-supervised way have proven to provide new SOTA results for various applications in natural language processing and computer vision. To investigate the benefit of foundation models in Earth Science applications, we deploy the large-scale representation model for atmospheric dynamics AtmoRep (Lessig et al., 2023) for statistical downscaling of the 2m temperature over Central Europe. AtmoRep has been trained on almost 40 years of ERA5 data from 1979 to 2017 and has shown promising skill in several intrinsic and downstream applications. By extending AtmoRep’s encoder-decoder with a tail network for downscaling, we super-resolve the coarse-grained 2 m temperature field from ERA5-data (Δx = 25 km) to attain the high spatial resolution (Δx = 6 km) of the COSMO REA6 dataset. Different coupling approaches between the core and tail network (e.g. with and without fine-tuning the core model) are tested and analyzed in terms of accuracy and computational efficiency. Preliminary results show that downscaling with a task-specific extension of the foundation model AtmoRep can improve the downscaled product in terms of standard evaluation metrics such as the RMSE compared to a task-specific deep learning model. However, deficiencies in the spatial variability of the downscaled product are also revealed, highlighting the need for future work to focus especially on target data that inhibit a high degree of spatial variability and intrinsic uncertainty such as precipitation.
Possible Observations of PKJKP in the AlpArray Seismic Dataset
Authors: Ling On Ki Angel , Stähler Simon C. , Giardini Domenico
Published: March 2024

Understanding the elastic properties of Earth's inner core is crucial for unraveling its role in the planet’s evolution and dynamics. Seismic shear waves provide a direct means to constrain the shear modulus of the solid inner core at high frequencies. However, their detection has been challenging due to their extremely weak amplitude and interference from other seismic arrivals (Doornbos, 1974). This study aims to provide direct observations of inner-core shear waves through a systematic search using the AlpArray Seismic Network (AASN), a large European seismic array. The approach combines 3-C polarization filtering and slant-stacking techniques. The inspection focuses on events between 2015 and early 2022 within the epicentral distance range of  ~110-150° from the AASN. This source-receiver geometry is close to that of previous PKJKP observation reported using the Gräfenberg array (Cao et al., 2005).Our systematic search and classification reveal multiple potential observations of PKJKP at frequencies > 0.1 Hz, consistent in both time and slowness with the 1-D Earth model ak135, as well as previous body-wave-based observations, particularly Wookey and Helffrich (2008). The new evidence of PKJKP demonstrates a path forward for formalizing a method for the repeatable detection of inner-core shear waves for different source-receiver geometries. Additional PKJKP observations and comprehensive modeling are essential for gaining insights into the intricate inner-core structure and phenomena, such as anisotropy and focusing effects, which could explain the limited number of observations to date.
The coherent solvus of disordered alkali feldspar determined with atom probe tomography
Authors: Heuser David , Dubosq Renelle , Bian Ge , Petrishcheva Elena , Habler Gerlinde , Gault Baptiste , Lengauer Christian Leopold , Rentenberger Christian , Abart Rainer
Published: March 2024

At high temperatures, alkali feldspar consists of a continuous solid-solution between the Na (albite) and K (K-feldspar) end members. Below about 600°C, a miscibility gap opens, the limits of which are determined by the so-called solvus. Alkali feldspar of intermediate composition tends to exsolve when cooled from temperatures of magmatic or metamorphic crystallization, forming an intergrowth of Na- and K-rich lamellae, a microstructure referred to as perthite. Initially, coherency is maintained across the lamellar interfaces and it may be preserved over geological times. Since the lattice parameters of alkali feldspars strongly depend on composition, the exsolution lamellae must be strained to maintain coherency at the interfaces. The elastic energy required to strain the lamellae counteracts exsolution and equilibrium compositions of coexisting coherent exsolution lamellae define a coherent solvus which lies below the solvus for strain-free phase equilibria. Segregation of Na and K and subsequent lamellar coarsening is achieved by thermally activated Na-K interdiffusion. Therefore, compositions and widths of the exsolution lamellae could be used to reconstruct cooling histories. Knowing the shape and position of the coherent solvus is key for the corresponding geo-speedometry applications.To determine the coherent solvus, initially homogeneous disordered, gem-quality alkali feldspar was annealed at temperatures between 440°C and 560°C and at atmospheric pressure, which caused it to exsolve into coherently intergrown 10 to 20 nm wide lamellae, the compositions of which were directly determined with atom probe tomography.The application of different annealing times showed that thermodynamic equilibrium was reached during the experiments. The obtained lamellar composition define points on the coherent solvus, which were for the first time measured directly for alkali feldspars.Additionally, equilibrium Na-K partitioning experiments between NaCl-KCl melt and the same alkali feldspars as used for the exsolution experiments were performed at atmospheric pressure and at temperatures between 800°C and 1000°C to calibrate a thermodynamic mixing model supplemented by a model for the elastic energy required for coherent exsolution. The coherent solvus calculated from the thermodynamic model and the directly measured coherent solvus are in excellent agreement. This indicates that the developed models provide an adequate description of phase equilibria in coherent lamellar intergrowth. The directly measured coherent solvus and the models form a solid base for potential applications of geo-speedometry in coherently exsolved alkali feldspars.
Snowmelt runoff characteristics in an alpine headwater catchment, Northern Japan Alps
Authors: Nakata An , Tsujimura Maki , Fujino Mayu , Kawabata Yuuri , Sakakibara Koichi , Suzuki Keisuke
Published: March 2024

It is important to understand the hydrological processes in the alpine headwaters, because the areas sustain the water resources in the down streams. In Japanese high mountain areas affected by Asian monsoon, there is large amount of precipitation in summer season, and is covered by vegetation even in the area with an elevation more than 2,000 m. We focus on snowmelt runoff processes in a Japanese alpine headwater catchment with different land cover conditions.We performed an intensive field monitoring at Mt. Norikura, a stratovolcano mountain, located at the southern end of the Northern Japan Alps with the maximum elevation of 3026m, specifically two headwater catchments, namely NR1 and NR2. The dominant area of NR1 is bare, whereas NR2 is covered by forest dominantly.We observed precipitation, temperature, and runoff of stream from 13th July to 11th October 2023. which includes snowmelt season. In addition, we collected stream water daily, and rainwater, snowmelt water, and spring water at the intervals of approximately two weeks. The concentrations of major inorganic solutions and stable isotopic ratios of oxygen and deuterium are determined on all water samples.The d-excess value of snowmelt water was higher than that of rainwater, whereas SiO2 concentration of groundwater/ spring water was higher than that of rainwater/snowmelt water. Therefore, we applied End Member Mixing Analysis（EMMA）to separate stream water into three components, rainwater, snowmelt water, and groundwater, using d-excess and SiO2 as tracers, focusing on snowmelt season. The EMMA results show that the snowmelt water contribution to the stream water was estimated to be 55% in NR1, whereas that in NR2 was estimates to be 25% in the beginning of snowmelt season, then the snowmelt component decreased gradually. The groundwater contribution to the stream water in NR1 was estimated to be 15%, whereas that in NR2 was estimated to be 75%.There results show that the effect of snowmelt water to stream water varies depending on land cover condition, snow cover and vegetation. The snowmelt component contributed to the stream water, even after the snow cover disappeared. This suggests that the snowmelt water would contribute to the stream water via the shallow groundwater nearby the stream in addition to the direct discharge.
Transient Attracting Profiles in the Great Pacific Garbage Patch
Authors: Kunz Luca , Griesel Alexa , Eden Carsten , Duran Rodrigo , Sainte-Rose Bruno
Published: March 2024

A major challenge for cleanup operations in the Great Pacific Garbage Patch is to predict day to day variabilities of plastic concentrations and to identify hotspots of marine debris. An ideal application would indicate material confluence at operational scales O(1 − 10km) but from mesoscale observations of sea surface height O(10 − 100km). The present study introduces the concept of TRansient Attracting Profiles (TRAPs, Serra et al. (2020), Serra and Haller (2016)) to this debate. TRAPs are computable from the instantaneous strain field on the ocean surface and act like short-term attractors for floating objects. Previous experiments have shown the potential of TRAPs to predict pathways of material transport and here we explore the occurrence of these profiles in the North Pacific subtropical gyre, a large-scale convergence zone that is known to entail the Great Pacific Garbage Patch. We compute TRAPs upon daily snapshots of near-surface geostrophic + Ekman current velocity and create a 20-years record of 4,076,065 TRAP objects. We identify 720,391 TRAP trajectories from this data and relate the propagation, persistence and attraction strength of TRAPs to detections of mesoscale eddies. We uncover a life cycle of long-living TRAPs and evaluate recurrent patterns in their vorticity environment. Our study culminates in an unprecedented statistical analysis of drifter motion around TRAPs. We highlight beneficial conditions for hyperbolic transport, estimate local retention times of drifters and find a preference of drifter visits during the formation stage of TRAPs. Our findings provide novel aspects towards mesoscale strain on the ocean surface and how it may benefit search operations at sea.
Robustness of the relationship between needle n-alkane δ²H and leaf water evaporative enrichment, amidst seasonally variable relationships between non-structural carbohydrate δ²H and respiration rate, in a boreal forest
Authors: Angove Charlotte , Wiesenberg Guido , Lehmann Marco , Saurer Matthias , Tang Yu , Sahlstedt Elina , Speckert Tatjana , Schiestl-Aalto Pauliina , Rinne-Garmston Katja
Published: March 2024

Stable isotopes of n-alkanes are important and rapidly developing tools for understanding paleoecology and past climatic conditions. However, there are knowledge gaps surrounding the physiological and environmental δ2H signals of n-alkanes. In this study, we investigated whether biosynthetic processes interfere with the consistency of the environmental signal in needle n-alkane δ²H. Therefore, we sampled two needle generations (one year-old needles, current-year needles) from five Pinus sylvestris trees at the boreal forest in Hyytiälä, Finland, during the 2019 growing season and analyzed δ2H of leaf non-structural carbohydrates (NSCs), starch, n-alkanes, and combined data with published leaf water isotope and shoot gas exchange measurements. We explored (1) time-integrated relationships between environmental variables and measured organic compound δ2H, and (2) evaluated whether the δ²H data of this study align with model predictions for NSC and leaf n-alkane δ²H values based on a process-based model for NSC δ2H hybridized with different leaf water heavy isotope enrichment and n-alkane models. Our findings suggest that NSC δ²H has temporally variable relationships to environmental variables which are related to needle generation and season, because current-year needle NSC δ²H was more closely correlated to respiration rate than a needle water isotope signal while one year-old needle NSC δ²H was more closely related to a leaf water evaporative enrichment signal. Interestingly, n-alkane δ²H did not exhibit the same seasonally variable relationship to respiration rate and were instead more closely related to a leaf water evaporative enrichment signal. Overall, results suggest that water compartmentalization in leaves can have a prominent enough role during n-alkane synthesis, that its effects can be observed at seasonal scale, which shows promise to the role of leaf n-alkane δ²H as a leaf evaporative enrichment signal without substantial interference by source water δ²H. However, we also highlight the role of signal dampening, by time integration and new needle growth. 
Quantifying human impact during industrialisation on the evolutionary trajectory of Vosgian streams (NE France): the value of documentary archives 
Authors: Jautzy Timothée , Jacob-Rousseau Nicolas , Berthier--Laumond Salomé , Claudepierre Margaux , Rixhon Gilles , Schmitt Laurent
Published: March 2024

The anthropogenic pressure on European rivers has greatly intensified since the Industrial Revolution through channelisation, rectification, and building of dams and weirs. Against this background, focusing on the Vosges Mountains (NE France) is particularly relevant since it is the most densely populated mountain range in France. The Vosgian hydrographic network was accordingly impacted by widespread human modifications. No less than ~5000 hydraulic structures (HS) mostly involving weirs were built across the main streams draining the massif. Contrary to large rivers (e.g. the Rhine), the edification periods of these HS in smaller catchments remains largely unknown yet, thereby impeding a precise chronological reconstruction of the main phases of human pressure and environmental trajectories. In this study, we aim to gain insight into the spatio-temporal anthropisation of three main streams draining the southern part of the Vosges, i.e. the Fecht, Vologne and Moselotte, and to evaluate their historical morphodynamic adjustments from the end of the 18th century onwards. We took advantage of the abundant paper archives, i.e. written reports, plans…, from the “Ponts et Chaussées” administration, which collected at the local scale every official request to build HS along and across streams from the 18th to the 20th century. Firstly, we characterised and mapped every weir and levee along the three studied streams to produce an updated database of the present distribution of HS. Secondly, we analysed the archives to date the construction (and in some cases deconstruction) of the HS. Finally, we reconstructed the diachronic evolution of the channel pattern, from an ancient topographical map (1866) and two orthophotos (1951, 2018). Our results allow a first quantification of human impacts: the year of construction (terminus ante-quem) could be assigned to 7%, 38% and 59% of the weirs currently present in the Fecht, Vologne and Moselotte, respectively. Most of them were probably built in the middle of the 19th century. Importantly, we also evidence a spatio-temporal correlation between the construction of HS and the simplification of the channel pattern. Although the use of historical documents has several limitations (e.g. loss, destruction, unavailability), we demonstrate that they are valuable archives that usefully complement field observations and investigations.
From Parks to Banks: Aligning Nature-Based Urban Green Space Assessment with Erosion Protection Goals
Authors: Obriejetan Michael , Krexner Theresa
Published: March 2024

The integration of urban green space management into erosion control for streambanks and embankments addresses essential environmental challenges by linking urban green spaces (UGS) with natural hazard (NH) mitigation. This strategic approach emphasizes comprehensive management that harmonizes seemingly different domains. At first glance, erosion stabilization measures and UGS appear distinct, yet they address similar processes from different perspectives. Central to this integration is vegetation assessment, vital for functions such as erosion control and urban ecosystem enhancement. Assessing vegetation through field evaluations and remote sensing is key for understanding how it interacts with soil, especially in terms of soil moisture, which is vital for slope stability and drought mitigation. This process is essential for evaluating the health and type of vegetation and its structural characteristics.Decision-making in system selection and management for erosion control should adopt a lifecycle perspective, encompassing environmental and economic impacts. This includes considerations from material selection to maintenance and eventual decommissioning, aiming for sustainable, cost-effective approaches. Additionally, there is a wealth of knowledge in communal and city green space management that can potentially be adapted and transferred to meet the requirements of erosion control. The choice of vegetation is crucial for decisions in both urban areas and for slope stabilization measures. The role of evapotranspiration in enhancing soil cohesion and reducing erosion risk, especially in urban green spaces (UGS) and nature-based systems, is significant. These methods not only ensure slope stability but also offer urban benefits, like mitigating urban heat island (UHI) effects. In adapting to climate change for effective erosion protection strategies, the key distinction is found in the detailed assessment of specific parameters from UGS and their application to erosion control methods. This focused evaluation ensures that erosion control measures are not only effective but also congruent with the distinct ecological aspects of urban environments. By carefully analyzing factors like vegetation type, soil characteristics, and water management in UGS, these insights become invaluable in strengthening the resilience and adaptability of erosion control strategies. This strategy goes beyond mere soil erosion reduction; it plays a pivotal role in enriching ecosystem capacities. By fostering biodiversity and refining the utility of green spaces, it contributes to the development of landscapes that are both sustainable and better equipped to adapt to climate change. This holistic approach underlines the multi-faceted benefits of integrating green space management into broader environmental resilience planning.
Projecting heat-related excess mortality under climate change scenarios in Europe: A multi-domain analysis
Authors: Relvas Hélder , Coelho Silvia , Rodrigues Vera , Isabel Miranda Ana , Lopes Myriam , Graça Daniel , Augusto Bruno , Basso João , Ferreira Joana
Published: March 2024

Recent studies have highlighted the diverse health consequences associated with climate change. However, a comprehensive evaluation of the specific susceptibilities of individuals and cities to these changes remains lacking. Addressing this gap, our study offers insights into potential excess mortality risks attributable to heat-related events under various climate change scenarios across diverse European regions, within the framework of the European Project DISTENDER.The primary objective of this research is to assess the potential impact of climate change scenarios, specifically Shared Socioeconomic Pathways (SSPs) SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, on heat-related excess mortality in a range of European locations. Focusing on Austria, the EURAF domain (encompassing parts of Portugal and Spain), a region in the Netherlands, the metropolitan area of Turin (Italy), and the urban area of Guimarães (Portugal), our investigation spans varied socio-geographic domains.By employing local-specific relative risk functions and daily average temperature data spanning 2015 to 2049, derived through statistical downscaling from CanESM5, EC-EARTH3, and MPI-ESM1-2-HR global climate models, our analysis encompasses resolutions ranging from 9000 to 500 meters, depending on the specific domain. This multidomain approach allows for capturing localized variations in climate impacts with high spatial resolution.The significance of our findings lies in their contribution to informing adaptive strategies, public health policies, and urban planning efforts aimed at mitigating the effects of climate change on vulnerable populations. Preliminary results indicate a distinct upward trend in heat-related excess mortality over the years, with the highest values observed for SSP5-8.5. Furthermore, there exists considerable variability among climate models.Acknowledgements:The authors would also like to acknowledge the support of CESAM (UIDP/50017/2020 + UIDB/50017/2020 + LA/P/0094/2020) and C2TN (UIDB/04349/2020). Thanks are due to the DISTENDER Project (Grant agreement ID: 101056836). Thanks are due to FCT/MCTES for the contract granted to Helder Relvas (10.54499/2021.00185.CEECIND/CP1659/CT0026).
Disentangling seasonal and annual precipitation signals in the tropics over the Holocene: insights from δD, alkanes and GDGTs
Authors: Hällberg Petter , Kylander Malin , Schenk Frederik , Villanueva Joan , Davtian Nina , Hapsari Anggi , Sjöström Jenny , Jarne-Bueno Guillermo , Yamoah Kweku , Rifai Hamdi , Smittenberg Rienk
Published: March 2024

Tropical Asia is a critical component of the global climate system as it provides large amounts of moisture and heat to the extratropics and drives monsoons on both hemispheres. Paleoclimate information remains relatively scarce from the region despite its global significance, calling for additional records from the region. We generated a multiproxy peat record from Sumatra, with a focus on deconvolving seasonal and annual precipitation signals, as well as long term temperature variability. We do this by analyzing the n-alkane distributions reflecting vegetation variability, and the hydrogen isotopic composition (δDalkanes) from alkanes sourced from algae and terrestrial plants. Algae grows during the wet season, while terrestrial plants grow over the whole year, and they therefore reflect the water isotopic signal from different parts of the year. We further analyze the GDGT composition in the peat core to derive information about temperature and hydrological changes. Finally, levoglucosan was measured to reconstruct past wildfire events.We find that the climate on Sumatra was much more seasonal in the Mid-Holocene than in the Late Holocene, based on the difference between δDterrestrial and δDalgae. In particular, the period between 4-6 ka BP was extremely seasonal, with alternating floods, droughts and fires. This extreme seasonality is coeval with an Asian Summer Monsoon collapse, Australian Summer Monsoon invigoration and the collapse of Green Sahara, suggesting large scale tropical atmospheric reorganization in that period.Our multiproxy annual precipitation reconstruction indicates the wettest overall conditions between 3.3-4.5 ka BP. which is approximately 1500-2000 years later than indicated by a nearby speleothem δ18O record, which instead is more similar to δDalgae. We therefore hypothesize that speleothem reconstructions in the region record a wet season isotopic signal, similar to the algae, since cave groundwater recharge occur mainly after heavy precipitation. The Late Holocene is marked by rapid drying around 2.8 ka BP, under a much less seasonal climate, which is coeval with the strengthening of ENSO variability in the Pacific Ocean.In summary, our multiproxy peat record from Sumatra resolves the seasonal versus annual components of past rainfall variability, revealing heightened seasonality during the Mid-Holocene, significant shifts in precipitation pattern, and a notable Late Holocene drying trend. Our findings highlight the importance of considering the δD signal from the full range of alkanes and considering seasonal variability in paleoclimatological reconstructions.
Emission Mechanism of radio bursts from the Solar Wind Acceleration Region observed by Parker Solar Probe in near-Sun plasmas
Authors: Ma Bing , Chen Ling , Wu De-Jin
Published: March 2024

    Solar and interplanetary radio bursts are important phenomena to reflect the electron acceleration and kinetic process in the corona and space plasmas. The near-Sun radio observation by Parker Solar Probe (PSP) provides an good chance to make the approach and in situ measurements for the emission source of radio bursts. According to the radio dynamic spectrum, we found that a large number of weak radio bursts with higher cutoff frequency flo can only be detected by PSP. These bursts have several obvious characteristics: (1) short duration (1-5 min); (2) narrow frequency band (0.5-15 MHz); (3) weak peak intensity (~ 10-15 V2/Hz). Their relative frequency drift rate decreases from > 0.01 s-1 to < 0.01 s-1 implies that they are not the typical type III and II radio bursts. Based on the plasma empirical models and the data from in situ detection by PSP, the fitted models indicate that the radiation of these bursts might be generated by the electron cyclotron maser emission in the acceleration region of solar wind (1.1-10 RS). The spectral characteristics of these bursts manifest that these bursts come from small-scale emission source, which have experienced strong kinetic evolution. We propose that these weak bursts are possibly the solitary wave radiation (SWR) generated from electron cyclotron maser instability with the energetic electrons trapped and accelerated by solitary kinetic Alfvén wave (SKAW) in the close magnetic structure. The decay of SKAW can well explain the deceleration of the emitting sources and the short duration.
Eddy Saturation and Latitudinal Storm Track Shift in a Reduced Two-level Model of the Atmosphere
Authors: Lucarini Valerio , Kobras Melanie , Ambaum Maarten
Published: March 2024

We introduce a minimal dynamical system derived from the classical Phillips two-level model with the goal of elucidating the essential mechanisms responsible for the interaction between eddies and mean flow. The choice of a two-level model as starting points allows for appreciating the relative role of barotropic and baroclinic processes. Specifically, we wish to explore the eddy saturation mechanism, whereby, when average conditions are considered, direct forcing of the zonal flow increases the eddy kinetic energy, while the energy associated with the zonal flow does not increase. The eddy-driven jet stream and storm tracks in the mid-latitude atmosphere are known to shift in latitude on various timescales, but the physical processes that cause these shifts are still unclear. Using our low-order model, we aim to understand the link between the structure of the eddies and the shift of the latitudinal maximum of the zonal flow in the mid-latitude atmosphere. Our findings elucidate the basic mechanisms behind baroclinic adjustment and provide insights into the properties of the storm track change between the jet entrance and jet exit regions of the North Atlantic.
New sea level scenarios for the Netherlands
Authors: Drijfhout Sybren S. , Le Bars Dewi , Keizer Iris
Published: March 2024

We present the framework used to develop a new set of sea level scenarios for the Dutch coast published by KNMI in October 2023, to help the Netherlands adapt to sea level rise. Based on interactions with stakeholders, the development of the scenarios focused on two main areas: the connection between observations and projections and the development of low-likelihood high-impact scenarios up to 2300. We developed a local sea level budget for the period 1993-2021 to better understand past observations and to constrain the scenarios. In particular, the contribution of Ocean Dynamic Sea Level was important in the benchmark period 1993-2021, and observational evidence was used to select CMIP6 models that were close to the observations. For the low-likelihood high-impact scenarios three lines of evidence were used: structured expert judgement, a numerical model including Marine Ice Cliff Instability, and a physical evidence discussion. We also discuss some practical applications of these scenarios.