bluuebunny/crossref_metadata_2025 huggingface dataset:
Political and physical limits to using formerly glaciated regions for hydropower production
Authors: Frøystad Rebekka , Born Andreas , Peters Yvette
Published: March 2024

Glacier retreat changes hydropower production, both by changing melt patterns and seasonality and by revealing new possible reservoirs. This holds potential for expanding the production of hydroelectric power. However, these glaciers are typically situated in valuable nature and protected areas, making the construction of new infrastructure difficult. Mitigating climate change by producing renewable energy therefore comes in conflict with protecting nature.In this study, we present survey results from the Norwegian Panel of Elected Representatives to investigate how democratically elected politicians approach such trade-offs, the conflict between protecting global climate or local nature. Which arguments drive support or opposition to building a hypothetical hydropower dam? How do they relate to the politicians' personal and political background? Interestingly, we find that politicians that are more concerned about climate change also are more opposed to building new hydropower infrastructure.In addition, we assess how the physical potential of hydropower will change in Norway under climate change. As a case study, we simulate the surface mass balance of Folgefonna ice cap to the end of the century under a range of climate scenarios. This enables us to quantify how uncertain such future projections are and to what degree we can provide policy makers with reliable information on hydropower potential. Thus, by a multidisciplinary approach, we assess both the physical and political potential for new hydropower due to glacier melt.
The space-time representation of extraordinary rainfall events
Authors: Manfreda Salvatore
Published: March 2024

Extraordinary events are rarely observable in a single rainfall gauge, and this make extremely challenging the correct prediction of their arrivals. However, it may be possible to develop a more robust approach by employing a space-time modelling scheme that is able to capture the spatial dynamics of such phenomena. Therefore, a space-time Poisson model of rainfall cells with circular shape and random depth has been exploited for the first time to interpret the behaviour of this family of extraordinary events. This category of events that may be connected to larger meteorological phenomena not necessarily connected with local heterogeneity of the landscape. Following the identification of the observed extraordinary event across southern Italy, six zones with significantly different dynamics in terms of the frequency of such extremes were identified. Subsequently, a simple mathematical representation was adopted to calibrate the model parameters, leading to an estimate of regional probability distributions defined on the space-time occurrences of extraordinary events over homogeneous zones. The approach allows to overcome the limitations posed by point observations allowed the definition of a probability distribution that pertains to an entire area rather than just a point. The obtained quantiles of rainfall estimated seems to align well with the upper bound of the probability distribution of the annual maxima observed over the areas of interests.Keywords: Rainfall statistics, Space-time Poisson models; Extraordinary events.
Subpixel classification of high-resolution satellite images to identify dune plants
Authors: Kombiadou Katerina , Costas Susana , Gallego-Fernández Juan B. , Yang Zhicheng , Silvestri Sonia
Published: March 2024

The increase in spectral and spatial resolution offered by satellite imagery opens new opportunities in ecosystem monitoring over broader scales. Combined with advances in machine learning algorithms, like the spectral unmixing methods, it is possible to extract information on features smaller than the pixel size, as previously demonstrated for the case of saltmarsh plants. The present study focuses on transferring subpixel classification algorithms to mid-latitude coastal dunes, a significantly more challenging environment in terms of plant size and density, as well as in terms of complexity and heterogeneity of the existing species. To this aim we obtained WorldView2 imagery over the Ria Formosa barrier islands (South Portugal) during May of 2023 and collected data on dune plant distribution over three barrier islands during the same period. A total of 800 m2 over the foredune (toe to lee) were photographed during fieldwork, identifying a total of 32 plant species. Plant density distribution was assessed at the level of the pansharpened satellite image pixel and the data were introduced to the Random Forest Soft Classification (RFSC) algorithm for training and validation. The sensing ability of the classifier was tested considering different parameters (number of trees, split criteria) and assessing the performance for increasing number of classes, along with the importance of the 8 spectral bands for each class. The results of the analysis provide insights on the strengths and limitations of the RSFC method for the especially challenging environment of mid-latitude coastal dune habitats and provide a step forward in coastal ecosystem remote sensing and monitoring of these environments. Acknowledgements: The work was implemented in the framework of the DEVISE project (2022.06615.PTDC), funded by FCT (Fundação para a Ciência e a Tecnologia), Portugal. K. Kombiadou and S. Costas also recognise the financial support of FCT through contracts CEECINST/00146/2018/CP1493/CT0011 and 2021.04286.CEECIND, respectively, and the support of national funds through FCT by projects LA/P/0069/2020, granted to the Associate Laboratory ARNET, and UID/00350/2020, granted to CIMA.
The active frontal sector of the offshore Northern Apennine thrust belt: insights from an interdisciplinary approach following the 2022 Mw 5.5 Costa Marchigiana Pesarese earthquake (Italy)
Authors: Petracchini Lorenzo , Billi Andrea , Carminati Eugenio , Chiarabba Claudio , Conti Alessia , Devoti Roberto , Palano Mimmo , Pezzo Giuseppe , Scognamiglio Laura , Tavani Stefano , Tinti Elisa
Published: March 2024

Identifying seismogenic faults in offshore regions presents significant challenges, particularly in achieving their precise geometry and kinematics. Geological data derived from deep-sea exploration and geophysical surveys are commonly used to characterize offshore active faults together with earthquake hypocentral locations. However, limitations may arise in the quantity and quality of geophysical available data, inhibiting the realization of accurate 3D models. Furthermore, the precise relocation of seismic events is demanding, especially in the depth domain, due to the limited azimuthal coverage and the minimum station-event distance that is well beyond the mean depth of the events. In this context, an interdisciplinary approach becomes imperative to mitigate over-interpretation and over-simplification in defining the seismogenic sources and establishing an all-encompassing rupture model.By means of an interdisciplinary (geological, seismological, and geodetic) approach, we investigate the outermost Northern Apennines fold-and-thrust belt front in the Adriatic Sea (Italy) involved in the Costa Marchigiana Pesarese seismic sequence started with the 9 November 2022 Mw 5.5 mainshock. Given the proximity of the mainshock and the subsequent seismic sequence to the urbanized coastline, where several cities are situated, characterizing the activated faults and the related estimation of ground displacement becomes crucial for seismic risk assessment and the tsunamigenic potential.We analysed the geological setting of the area by means of an accurate interpretation of numerous seismic reflection profiles and well data acquired over the past decades, which complemented the publicly available seismic data. The interpretation of this dataset, provided by oil companies, led to an accurate definition of the thrust systems highlighting both the geometry of the activated sector of the thrust front and its relation to potentially active adjacent faults. Moreover, the results show the strong influence of past paleogeography and paleomorphology on the evolution and geometry of this sector of the fold-and-thrust belt, including the buttressing effect of carbonate platforms and inherited highs.The resulting 3D model was integrated with seismological data and geodetic observations allowing us to well highlight the activated portion of the fault plane: strong motion data and continuous GNSS stations hosted by onshore (storage centers) and offshore (seabed-anchored hydrocarbon platforms) infrastructures were jointly inverted to retrieve the Mw 5.5 coseismic rupture history.
Unveiling Climate-Induced Ocean Wave Activities Using Seismic Array Data in the North Sea Region
Authors: Zhong Yichen , Gu Chen , Fehler Michael , Prieto German , Wu Peng , Yuan Zhi , Chen Zhuoyu , Kang Borui
Published: March 2024

Climate events may induce abnormal ocean wave activities, that can be detected by seismic array on nearby coastlines. We collected long-term continuous array seismic data in the Groningen area and the coastal areas of the North Sea, conducted a comprehensive analysis to extract valuable climate information hidden within the ambient noise. Through long-term spectral analysis, we identified the frequency band ranging from approximately 0.2Hz, which appears to be associated with swell waves within the region, exhibiting a strong correlation with the significant wave height (SWH). Additionally, the wind waves with a frequency of approximately 0.4 Hz and gravity waves with periods exceeding 100 seconds were detected from the seismic ambient noise. We performed a correlation analysis between the ambient noise and various climatic indexes across different frequency bands. The results revealed a significant correlation between the North Atlantic Oscillation (NAO) Index and the ambient noise around 0.17Hz.Subsequently, we extracted the annual variation curves of SWH frequency from ambient noise at each station around the North Sea and assembled them into a sparse spatial grid time series (SGTS). An empirical orthogonal function (EOF) analysis was conducted, and the Principal Component (PC) time series derived from the EOF analysis were subjected to a correlation analysis with the WAVEWATCH III (WW3) model simulation data, thereby confirming the wave patterns. Moreover, we conducted the spatial distribution study of SGTS. The spatial features revealed that the southern regions of the North Sea exhibit higher wind-wave energy components influenced by the Icelandic Low pressure system and topography, which explains the correlation between ambient noise in the region and the NAO index. Furthermore, spatial features disclosed a correlation between the first EOF mode of the North Sea ocean waves and the third mode of sea surface temperature anomalies. This research shows the potential of utilizing existing off-shore seismic monitoring systems to study global climate variation and physical oceanography.
Plant-derived organic exudates in soil: Mobility and aggregation
Authors: Guhra Tom , Schönherr Jona , Totsche Kai Uwe
Published: March 2024

Plant derived photosynthates are a component of the biotic organic matter involved in carbon cycling and storage due their mobility and formation of organo-mineral associations and (micro-)aggregates. Such photosynthates are typically found as components of mucilage or generate during the germination of seeds in the soil environments. While the effect of, e.g., mucilage, on soil physical properties has been intensively investigated, their role for carbon transport, adsorption, and aggregation process is rather unclear. Most of the knowledge available originates from studies that used single compounds, e.g., oxalic acid, glucose, polygalacturonic acid or mixtures of those in aqueous solutions. In our study, we utilized hydrogel-freed plant exuded photosynthates (PDE) extracted from four different seed types (Linum usitatissimum, Plantago ovata, Ocimum basilicum and Salvia hispanica) to investigate their interactions with minerals typically for temperate soil. In batch experiments, PDE adsorbed to both illite and goethite minerals with a preference of polysaccharide-rich PDE to goethite. During the adsorption, organo-mineral associations were formed leaving behind a less mineral-affine fraction of PDE prone to transport or degradation. Hence, PDE transport was also studied in column experiments using quartz functionalized with reactive minerals where we measured the breakthrough of PDE exploiting their distinct fluorescence. Furthermore, we followed the gravity-constrained aggregation dynamics of PDE-mineral associations using tensiometric measurements. We showed that low PDE concentrations facilitate aggregation via polymer bridges leading to a rapid sedimentation of aggregates while PDE available in excess prevents aggregation via steric repulsion and thus decelerates sedimentation. These results showed that PDE extracted from seeds might serve as better surrogates of natural plant exudates to study their role for the formation and transport of organo-mineral associations and aggregates in soils.
Determining factors of soil organic carbon in the sclerophyll ecosystem of central Chile
Authors: Mallitasig Nancy Daniela , Miranda Marcelo , Arellano Eduardo
Published: March 2024

The sclerophyllous forest of Central Chile, a Mediterranean-type ecosystem, is facing increasing vulnerability, exacerbated by anthropogenic pressures and drought conditions that have intensified over the past decade.The objective of this study was to determine, at both regional and local scales, the factors influencing soil organic carbon (SOC), considering the integrated soil-vegetation system. Biophysical conditions such as primary productivity (PP), soil properties (SP), terrain physiography, and climate were considered.At the regional scale, predictive variables for PP were selected using remote sensing techniques, including the Enhanced Vegetation Index (EVI) and the Normalized Difference Water Index (NDWI) in the spring period. Additionally, climatic variables (maximum, mean, and minimum temperature in spring and annual precipitation between 2001 and 2021) and physiographic variables such as exposure, slope, elevation, and topographic position index (TPI) were included. Statistical analysis was analyzed using a Random Forest model.At the local scale, a forest inventory has been made, and soil samples were taken at a depth of 20 cm in 45 field plots of 400 m2, located in multi-species shrub vegetation (>4m in height). Concentrations and stocks of SOC were quantified, along with physical properties (texture, field capacity, and macroaggregates), chemical properties (pH, organic matter content, total nitrogen, and C/N ratio), and microbial activity estimated through basal respiration. Biomass, nitrogen content, and C/N ratio of leaf litter also measured. Statistical analysis was performed using a stepwise regression.Preliminary results indicate that the most significant variables in predicting SOC were EVI, slope, elevation, total nitrogen, DA, LAI, coverage of the tree stratum, and vegetation height at the corresponding spatial scale.
Support Toolbox for Urban Adaptation to Heat Waves in Romania
Authors: Dumitrescu Alexandru , Cheval Sorin , Chițu Zenaida , Falcescu Vladut , Gabrian Ștefan , Dinicilă Ștefan
Published: March 2024

A comprehensive toolbox has been developed to support urban adaptation to heat waves (HWs) in the context of the current climate and climate change. The toolbox consists of the following components: (1) full methodology for analysing the interactions between urban heat islands (UHIs) and HWs in the context of climate change; it is exemplified for the city of Bucharest, Romania, but the methodologies used can be easily applied to other cities; (2) a web-based tool that allows users to explore the impacts of different climate change scenarios on the interactions between UHIs and HWs;  for example, users can input changes in land cover, population growth, and temperature and see how these changes affect the UHI-HW relationship in a particular city;  (3) guidelines and specific measures to better cope with the UHI and HW stress under current and future climate conditions, tailored to the specific context of each city; adaptation and mitigation options are included (i.e., more greenery and lesser disruption of the natural water cycle supporting current policies for climate change resilience).The support toolbox based on an interactive Shiny application built in R and Python provides a comprehensive set of tools and resources, which allows urban planners, policymakers, and stakeholders to make informed decisions about how to adapt to and mitigate the effects of HWs. The interactive features of the application enable users to intuitively visualize and interact with urban adaptation data, thereby facilitating a deeper understanding of the problem and potential solutions.This study received funding from the project Synergies between Urban Heat Island and Heat Wave Risks in Romania: Climate Change Challenges and Adaptation Options (SynUHI) PN-III-P4-PCE-2021-1695.
Mid-term observation of the degassing dynamics of the Kolumbo submarine volcano (Aegean Sea) gained by new-generation stand-alone multidisciplinary seafloor observatory
Authors: Sciré Scappuzzo Sergio , Lazzaro Gianluca , Longo Manfredi , D'Alessandro Walter , Grassa Fausto , Semprebello Agostino , Nomikou Paraskevi , Polymenakou Paraskevi , Rizzo Andrea Luca , Mallios Angelos
Published: March 2024

The underwater volcanic activity associated with deep-seated mantle processes represents a primary driver of the chemical and biogeochemical evolution of the global oceans. Hydrothermal activity is often a manifestation of submarine volcanism, where fluxes of heat and magmatic volatiles confer both potential hazard and opportunities of resource exploitation. Despite this, research on shallow submarine arc volcanoes is still in an early stage and only a few continuous seafloor observing infrastructures have been developed until now.  The Kolumbo underwater volcano, located in the Aegean Sea, hosts one of the most active and dynamic hydrothermal vent fields, marking it - along with the proximity to the world-known Santorini island - a severe geohazard for a combination of reasons. Within the framework of the SANTORY (SANTORini’s seafloor volcanic observatorY) project, funded by the Hellenic Foundation for Research and Innovation and with the financial support of the Municipality of Thira, between 2022 and 2023, three oceanographic cruises were performed on submarine Kolumbo volcano. The oceanographic surveys were mainly aimed at the deployment of integrated operating sensors of state-of-the-art technology, for in situ monitoring. A new-generation stand-alone multiparametric observatory has been developed at INGV Palermo and deployed at the bottom of the crater (500 meters depth) for the first time in December 2022. The battery powered module has been able to operate autonomously for a 10-month-long period, collecting a dense, heterogeneous dataset able to describe the activity of the hydrothermal reservoir, highlighting its intense dynamic along the time.In June 2023, the observatory was recovered and re-deployed after brief maintenance operations including battery charging and data downloading. Finally, in October 2023, the observatory was definitely recovered.Here we present for the first time a mid-term-long chemical-physical data series acquired (pH, temperature, hydrostatic pressure, turbidity, conductivity, dissolved methane) along with passive acoustic and the preliminary findings of the system evolution within the observing window. A variety of local VT events likely sourced in the deeper portion of the plumbing system, together with several other minor seismic events related to fluid dynamics inside “fluid-filled” cracks and conduits has been revealed by passive acoustic data. Moreover the acoustic sensor recorded all the signals generated by the bubbles along the water column. The obtained results gave back an up to date picture of the ongoing Kolumbo degassing dynamics, hydrothermal and seismic activity. 
From outcrop to spectrum
Authors: Lünsdorf Nils Keno , Lünsdorf Jan Ontje , Újvári Gábor , Dunkl István , Wolfram Lukas , Hobrecht Adrian , Laake Lothar , von Eynatten Hilmar
Published: March 2024

Reconstructing source to sink relationships or the origin of sediments and sedimentary rocks is the main goal of sedimentary provenance analysis. Several processes alter the source signal during transport and deposition and the extraction of the initial provenance signal is usually realized by combination of multiple single grain methods determining mineralogy, chemical composition or radiometric ages. However, such methods are mostly applied to sand-sized sediments or sedimentary rocks, while finer grained material is usually analyzed by whole-rock geochemical means and seldom by single-grain methods. Considering the abundance of fine-grained sedimentary archives and that short lived climatic signals are frequently encoded in such archives (e.g. loess, varves, etc.), a strong need for single-grain, multi-method analyses of silt-sized sediments is obvious.Therefore, we developed a highly automated approach to modal mineralogy of silt-sized sediments and sedimentary rocks based on image segmentation and object detection capabilities of machine learning methods, which allows for correlative analysis (e.g. optical microscopy, Raman spectroscopy, SEM, EPMA, LA-ICP-MS) and increased sample throughput.To test if our approach is feasible for silt-sized sediments, we sampled three loess-paleosol-sequences (LPS) of similar age and from different loess domains. Based on heavy mineral compositional data and zircon U-Pb age distributions the LPSs can readily be differentiated, verifying the feasibility of our approach. Consequently, we hypothesize that this novel multi-method, high-throughput data acquisition within a highly automated workflow will allow for hitherto unprecedented spatial and temporal resolution as well as statistical significance of provenance information, potentially enabling new research pathways in sedimentary provenance analysis.
It Takes Two to Tango: The Twin Anthropogenic Greenhouse Gas Observers 
Authors: Landgraf Jochen , Veefkind Pepijn , Cooney Ryan , Goudar Manu , Laasner Raul , de Groot Zeger , Alpay Koc Nurcan
Published: March 2024

The Twin Anthropogenic Greenhouse Gas Observers (TANGO) mission is a pioneering Cubsat satellite mission comprising two satellites, TANGO-Carbon and TNAGO-Nitro. Secured by national funding Tango will be launched in the year 2027 and envisages a unique European contribution to monitoring globally and independently the emission of anthropogenic greenhouse gases CO2 and CH4 over the period 2027-2031. To this end, breakthrough technology will be used to quantify emissions of the greenhouse gases methane (CH4) and carbon dioxide (CO2) at the level of individual industrial facilities and power plants. The mission will demonstrate a distributed monitoring system that will pave the way for future larger constellations of Cubsats allowing for enhanced coverage and temporal resolution. The TANGO mission consists of two agile satellite buses flying in formation, each carrying one spectrometer. The first satellite measures spectral radiances in the shortwave infrared part of the solar spectrum (1.6 µm) to detect moderate to strong emissions of CH4 (≥ 5 kt/yr) and CO2 (≥ 2 Mt/yr). The instrument has a field of view of 30 x 30 km2 at spatial resolutions small enough to monitor individual large industrial facilities (300 x 300 m2), with accuracy to determine emissions based on a single observation. Using the same strategy, the second satellite yields collocated NO2 observations from radiance measurements in the visible spectral range, supporting plume detection and exploiting the use of CO2/NO2 ratio. TANGO will provide surface fluxes of specific emission types based on the combination of CH4, CO2, and NO2 observations at a high spatial resolution following a strictly open data policy. Mission operation will be open for input from the science community on target selection. In doing so, TANGO aims to uniquely complement the large, planned Copernicus monitoring missions like Sentinel-5 and the CO2M mission by providing unrivaled high-resolution monitoring of the major anthropogenic greenhouse gas emissions regularly. In this presentation, we will discuss the TANGO mission concept and its synergy with future Copernicus missions.
Using WMO's Competencies for the Provision of Climate Services in Bachelor's Degree: The Experience of the URV's Bachelor in Geography, Territorial Analyis and Sustainabilty
Authors: Olano Pozo Jon Xavier , Boqué-Ciurana Anna , Aguilar Enric , Alberich Joan , Sigró Javier , Gutiérrez Aaron , Caterina Cimolai
Published: March 2024

In the previous decade, different WMO expert teams drafted the Competencies for the Provision of Climate Services (WMO, 2019). In awareness of the importance of Climate Services, the Universitat Rovira i Virgili's Bachelor's Degree on in Geography, Territorial Analysis features two courses specifically mapped to this competency framework. Strategically placed in the 2nd and 3rd year, these courses offer 12 ECTS, equipping students with core knowledge and skills for delivering climate services. The curriculum includes a participatory methodology, encouraging co-creation, user engagement, and responsiveness to user needs, as highlighted in research by Font et al. (2021). This approach, contrasting traditional educational models, fosters a dynamic, interactive learning environment. Students undertake a workflow in line with the WMO's framework for climate service provision. 

Project 3, the first course, focuses on the first two core competencies: C1 Create and Manage Climate Data Sets (covering quality control and data homogenization) and C2 Derive Products from Climate Data. This first course establishes an understanding of climate data management and product development and introduces the students to programming applications. The second course, "Project 5: Co-creation of Climate Services", further develops the coding skills and emphasizes communication skills (C5, Communicate Climatological Information with Users). It reviews database creation, and the development of products tailored to sectoral areas of local significance, like tourism or cultural events or high-priority areas identified by the Global Framework for Climate Services (GFCS), such as Health. The program's emphasis on co-creation and sector-specific applications highlights its commitment to practicality and real-world relevance in climate service fields. 

Competency development in these courses is assessed against various learning outcomes aligned with the WMO's guidelines for climate service provision. Student progress is evaluated through diverse criteria, adhering to a "learning by doing" approach. This methodology provides a hands-on experience and facilitates continuous skill improvement guided by instructor feedback. This experiential learning model is crucial for integrating theoretical knowledge with practical application, preparing students for professional challenges in climate-related fields. 
Enhancing National Flood Forecasting: Leveraging Library-based Surrogate Models for Impact-based Warnings
Authors: Mosimann Markus , Kauzlaric Martina , Schick Simon , Martius Olivia , Zischg Andreas Paul
Published: March 2024

In Switzerland, the Federal Office for the Environment issues hydrological forecasts and general flood warnings for the main river network. However, recent global flood events underscore that gaps in the communication channels from warning services to target groups inhibit effective mitigation efforts. One approach addressing this issue is impact-based warning.Aligned with Switzerland's existing flood forecasting system, we introduce a library-based surrogate flood model approach aimed at advancing current technologies towards robust impact-based warning systems. We evaluate the model based on the main river network of Northern Switzerland by comparing the impacts to buildings, persons and workplaces with hazard classification, estimated with transient simulations for nine extreme precipitation scenarios.Across 78 analyzed model regions, our surrogate approach yields a Flood Area Index between 0.74 and 0.90 for each scenario (overall 0.84) compared to the transient, computationally expensive flood modelling approach. Furthermore, the Critical Success Index, computed based on exposed persons, ranges between 0.77 and 0.93 (overall 0.89).Our prototype of a library-based flood surrogate model demonstrates the ability of accurately replicate highly resolved transient models This capability bears the potential of nationwide real-time flood impact prediction and potential integration into probabilistic forecasting. Leveraging an API, this library-based approach could enhance the existing forecasting system, offering a pathway toward impact-based flood warnings.
Environmental conditions controlling Cold-water corals occurrence in western Melilla (western Mediterranean) since the last deglaciation.
Authors: Selvaggi Mar , de la Fuente Maria , Català Albert , Pérez-Asensio José Noel , Lo Iacono Claudio , Haghipour Negar , Trias-Navarro Sergi , Corbera Guillem , Di Bella Letizia , Cacho Isabel
Published: March 2024

Cold-water coral (CWC) mounds are widely distributed in the eastern Alboran Sea (westernmost Mediterranean), specifically in the so-called East and West Melilla CWC mound provinces (EMCP, WMCP). Here we present a study on the environmental changes that occurred in the WMCP since the last deglaciation (~14 kyr BP), based on the analysis of the sediment core MD13-3451 (370 m water depth). The reconstructed palaeoceanographic changes allowed for the identification of diverse circulation patterns, which potentially influenced the life and demise of CWC communities in the WMCP. The analyses performed include sediment grain-size, geochemical measurements in foraminifera coating (U/Mn ratio) and calcite (stable isotopes, Mg/Ca-derived Deep Water Temperatures; DWTs), and the assessment of benthic foraminiferal species assemblages tolerating low-oxygen conditions (relative abundance of Globobulimina affinis). Furthermore, seawater δ18O (δ18Osw) and seawater δ18O corrected for the ice volume signal (δ18Ow-ivc) have been estimated via paired analyses of Mg/Ca and δ18Ocarbonate. Our findings suggest: i) the occurrence of pulses of relatively high DWTs, moderate to strong bottom water hydrodynamics and well-oxygenated waters favored a suitable environment for CWCs during the Early Holocene (EH), ii) a rapid freshening of the waters occurred during the EH, indicating major oceanographic changes. These results, when combined with available records from neighboring sites, reveal that such flourishing stage is closely coupled to a re-organization of the Alboran Sea water column structure. More precisely, the emergence of a newly formed water mass probably originated in the Gulf of Lion (northwestern WM) most likely replaced the older Levantine Intermediate Water (LIW) and might have also promoted the reactivation of CWC growth. Overall, our results highlight the crucial role of the Mediterranean circulation and stratification in controlling the temporal development of CWC mounds in the southern Alboran Sea, and also emphasize the importance of integrating a wide range of environmental variables and spatial scales when investigating these complex ecosystems.
Very High Energy Solar Energetic Particle Events and Ground Level Enhancement Events: Forecasting and Alerts
Authors: Crosby Norma , Mavromichalaki Helen , Malandraki Olga , Gerontidou Maria , Karavolos Michalis , Lingri Dimitra , Makrantoni Panagiota , Papailiou Maria , Paschalis Pavlos , Tezari Anastasia
Published: March 2024

A Ground Level Enhancement (GLE) event can be observed as an increase in the background of ground-based neutron monitor observations and is often associated with an increase of >500 MeV space-based proton flux measurements. GLE events begin as very high-energy SEP events associated with GeV protons. For such events to be detected at sea level, proton energies must exceed about 433 MeV. To mitigate for potential impacts on space systems, avionics and human health, space-based and ground-based monitoring of these particles is essential, and so is having reliable real-time warning systems. Here we present two products, respectively, “GLE alert++” and “HESPERIA UMASEP-500”, that have been fully integrated as federated products on the ESA SWE Portal for this purpose. GLE alert++, built by the Athens Cosmic Ray Group of the National and Kapodistrian University of Athens, issues alerts when a GLE event has been registered and is based on ground-based neutron monitor observations. From the space-based approach, the EU HORIZON2020 HESPERIA UMASEP-500 product provides forecasts of GLE events and >500 MeV protons relying on GOES satellite soft X-ray and high-energy proton observations. Examples of how these two products complement each other will be given, as well as how using them together can in some instances provide more information for users of these services. (Work performed in the frame of ESA Space Safety Programme’s network of space weather service development and pre-operational activities, and supported under ESA Contract 4000134036/21/D/MRP.)
Understanding non-linear ground response with Distributed Dynamic Strain Sensing (DDSS) at Mt. Etna volcano, Sicily.
Authors: Diaz-Meza Sergio , Jousset Philippe , Currenti Gilda , Costes Lucile , Krawczyk Charlotte
Published: March 2024

Mt. Etna, the largest volcano in Europe, is known for its almost persistent activity and complex seismic wavefield, making it an attractive location for examining volcanic explosions and testing new instrumentation in seismology (e.g., rotational sensors, strain-meters, fiber optic sensing). In 2018, a study was conducted at the Pizzi Deneri (PDN) observatory, situated near Mt. Etna’s summit to understand new instrumentation responses to the local seismo-acoustic wavefield. During volcanic explosions the released energy is mainly partitioned into seismic waves traveling through the ground, and sound waves traveling through the atmosphere. To capture this phenomenon, a temporary multi-parameter network comprised of infrasound sensors, broad-band seismometers (BB) and a fiber optic cable buried within the local loosed granular medium (scoria layer). The fiber optic cable was connected to a Distributed Dynamic Strain Sensing (DDSS) interrogator.At Etna, volcanic explosions were observed at co-located BB, infrasound and DDSS virtual sensors. A notable example(visible in both BB and DDSS data) is the successive occurrence of a 1-2 Hz seismic signal with a duration of ~4 seconds, followed by a ~2 Hz acoustic signal originating from the explosion, recorded at infrasound sensors. Unusually, simultaneous to the arrival of the acoustic signal observed at the infrasound sensors, DDSS and BB sensors record a signal with a frequency content of 15-20 Hz with a duration of ~2 seconds. We hypothesize that the 15-20 Hz signal is resulting from a non-linear ground response due to the air-to-ground coupling of the air pressure wave.In order to better characterize this phenomenon, a second experiment was conducted in 2019 at PDN with a similar instrumentation as in 2018, but with a different spatial arragenment. During three months the infrasound sensors recorded each about 65000 volcanic explosions. In this work we analyze the respective ground responses of volcanic explosions observed in the DDSS records of the 2019 campaign. We observe similar phenomenon as in 2018 (non-linear ground response), nevertheless, not all explosion can trigger this response. We first characterize the explosion events from both infrasound and DDSS records, and then classify them using their waveform similarity. The preliminary results provide a broad characterization of the non-linear ground response phenomenon and an insight into the physical properties and processes that are necessary for a pressure wave to trigger a non-linear ground response. The outcomes of this work provide a better understanding of acoustic-to-ground energy coupling in volcanic environments and their potential to trigger other hazards.
Investigating seasonal to decadal variability in the electron density of the mesosphere using historical EISCAT data
Authors: Reidy Jade , Kavanagh Andrew
Published: March 2024

The mesosphere/lower-thermosphere/ionosphere (MLTI) region is a critical boundary in the coupling of the atmosphere, climate and space weather, however it is one of the least understood regions, making it hard to include in whole atmosphere models. The EISCAT radars at Tromsø (UHF and VHF) have been measuring ionospheric parameters, such as electron density, for almost 4 decades making them an excellent resource to study changes in the ionosphere over a long time period.  We have generated two data archives using 20 years of observations of EISCAT Tromsø from 2001 to 2021; the data have been re-analysed at 10-minutes and 1-hour integrations. These archives are used to study the different sources of variability in the MLTI from 50-200 km. This is the first time the mainland EISCAT data has been converted into a format that allows for long term statistical study. We have created electron density climatologies split by solar, geomagnetic and atmospheric indices to investigate the different drivers of variability in the MLTI region. We show seasonal averages of the electron density altitude profiles and compare our results to the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) and the Whole Atmosphere Community Climate Model.
Distribution of soil organic carbon across contrasting fractionation techniques - results from a long-term field trial with increasing shares of leguminous cover crops
Authors: Binacchi Ferdinando , Veloso Murilo , Bayer Cimélio , Poeplau Christopher , Mueller Carsten , Buegger Franz , Gattinger Andreas
Published: March 2024

Diversification of no-till cropping systems through the inclusion of leguminous crops can be a sustainable means for enhancing both the bioavailability as well as the persistence of soil organic carbon (SOC). Therefore a comprehensive assessment of long-term soil organic matter (SOM) dynamics is crucial to realize the potential of sequestering atmospheric carbon dioxide, while concomitantly restoring the productivity and functionality of degraded soils. In the current study, soil samples were taken from a 39 years old subtropical trial at seven soil increments until one meter depth. Treatments included five maize-based cropping systems, with increasing shares of leguminous cover crops, with or without nitrogen (N) fertilizer applications to the maize plants. Varying degrees of labile and recalcitrant SOC were distinguished by means of thermal analysis as well as through physio-chemical fractionation, yielding contrasting results in shares of carbon accumulation across conceptual pools. While thermally recalcitrant SOC (combusted at temperatures between 400˚C and 800 ˚C) represented a small percentage of total C accrual, chemically recalcitrant SOC (silt and clay fraction resisting sodium hypochlorite oxidation) reported both a large share of total C content, as well as a high C accumulation. Although limited overlap among C pools from the two fractionations was found, irrespective of C detection method, systems with higher shares of leguminous cover crops reported highest SOC stocks. Interestingly, including additional leguminous cover crops contributed in storing as much SOC as systems with N fertilization, but the depth at which SOC sequestration occurred varied between fertilized and non-fertilized systems. While SOC stocks in the 0-30 cm depth correlated positively to total C inputs from crop residues in both fertilized and unfertilized systems, SOC stocks in the subsoil (30-100 cm depth) only correlated (p
Global ocean ventilation: a comparison between a general circulation model and data-constrained inverse models
Authors: Millet Bruno , de Lavergne Casimir , Gray William , Holzer Mark , Roche Didier
Published: March 2024

Ocean ventilation, or the transfer of tracers from the surface boundary layer into the ocean interior, is a critical process in the climate system. Here, we assess steady-state ventilation patterns and rates in three models of ocean transports: a 1° global configuration of the Nucleus for European Modelling of the Ocean (NEMO), version 2 of the Ocean Circulation Inverse Model (OCIM), and the Total Matrix Intercomparison (TMI). We release artificial dyes in six surface regions of each model and compare equilibrium dye distributions as well as ideal age distributions. We find good qualitative agreement in large-scale dye distributions across the three models. However, the distributions indicate that TMI is more diffusive than OCIM, itself more diffusive than NEMO. NEMO simulates a sharp separation between bottom and intermediate water ventilation zones in the Southern Ocean, leading to a weaker influence of the latter zone on the abyssal ocean. A shallow bias of North Atlantic ventilation in NEMO contributes to a stronger presence of the North Atlantic dye in the mid-depth Southern Ocean and Pacific. This isopycnal communication between the North Atlantic surface and the mid-depth Pacific is very slow, however, and NEMO simulates a maximum age in the North Pacific about 900 years higher than the data-constrained models. Possible causes of this age bias are interrogated with NEMO sensitivity experiments. Implementation of an observation-based 3D map of isopycnal diffusivity augments the maximum age, due to weaker isopycnal diffusion at depths. We suggest that tracer upwelling in the subarctic Pacific is underestimated in NEMO and a key missing piece in the representation of global ocean ventilation in general circulation models.
Exploring the Functional Persistence of Mycorrhizal Associations in Water Uptake during Soil Drying Conditions 
Authors: Kraus Alora , Hafner Benjamin D. , Adamczewski Ruth , Zare Mohsen
Published: March 2024

Arbuscular mycorrhizal fungi (AMF) are well-known to enhance plant resilience to water stress by improving water uptake from the soil. Few studies, however, address direct water transport to plant roots through hyphal networks, and it is virtually unknown how this function responds to soil drying. This study investigates AMF involvement in maize root water uptake across different soil water content conditions. Our primary objective is to explore how the direct contribution of AMF to root water uptake changes as soil dries. Zea mays (maize) plants were cultivated in experimental pots (4.1 L) filled with a 70% sand and 30% clay soil mixture. The pots were partitioned into two compartments using 31-μm nylon mesh, creating a 3.5-mm air gap to restrict root growth to the primary plant compartment and ensure exclusive access of mycorrhizal hyphae to a secondary soil compartment. Maize seeds inoculated with Glomus intraradices spores were cultivated for six weeks in the primary compartments under well-watered conditions before being subjected to one of three soil moisture regimes: well-watered (28-31% volumetric soil water content), moderate drought stress (14-17% volumetric soil water content), or severe drought stress (8-11% volumetric soil water content). When plants were eight weeks old, 2H-labelled water was added exclusively to the hyphae-only compartment, allowing for tracking and quantification of AMF-transported water. During and after labelling, plant shoots were enclosed in air-tight plastic bags connected to a stable isotope analyzer, which continuously monitored plant transpiration and 2H concentrations in transpired water vapor over a four-day period. Results from staining techniques demonstrate robust mycorrhizal colonization of roots and successful hyphal penetration across the air gap into the hyphae-only compartment. Results from the 2H labeling experiment indicate an early arrival of 2H in the transpired water of plants subjected to moderate drought stress (two days post-labelling) compared to well-watered conditions and severe drought stress (three days post-labelling). Additionally, plants exposed to drought stress exhibited higher 2H concentrations in their transpired water, suggesting an enhanced contribution of AMF to root water uptake under soil drying conditions. This investigation offers insights into the dynamics of AMF hyphal water transport under distinct soil moisture conditions. The outcomes will advance our understanding of mycorrhizal symbioses’ response to drought stress, potentially guiding strategies to optimize plant water acquisition in agricultural contexts facing escalating water scarcity challenges.
Large biases in soil moisture limitation across CMIP6 models
Authors: Giardina Francesco , Padrón Ryan S. , Stocker Benjamin D. , Schumacher Dominik L. , Seneviratne Sonia I.
Published: March 2024

Accurate soil moisture representation is crucial in climate modeling, due to its significant role in land-atmosphere interactions. Our study focuses on water storage dynamics and analyzes how soil moisture limitation is represented in simulations from the land component (land-hist experiment) of seven models within the Coupled Model Intercomparison Project phase 6 (CMIP6). We quantified the annual maximum depletion in soil moisture, contrasting model results with observations of terrestrial water storage from the Gravity Recovery and Climate Experiment (GRACE). Our analysis shows that CMIP6 models mostly underestimate these annual extremes in soil moisture reductions, with the Amazon consistently emerging as the most biased region. We further computed the critical soil moisture thresholds and quantified the frequency of soil moisture limitation in CMIP6 simulations, comparing model estimates against solar-induced fluorescence (SIF) and GRACE observations. We found consistent results with the annual maximum depletion in soil moisture, with models almost always overestimating the frequency of soil moisture limitation globally compared to observations. We validated our findings with data from 128 eddy-covariance sites from eight biomes worldwide. Our study illuminates the biases in soil moisture storage and dynamics between CMIP6 models and empirical observations, highlighting the importance of improving the representations of soil moisture and land-atmosphere interactions in Earth System Models.