bluuebunny/crossref_metadata_2025 huggingface dataset:
AQUA: a novel quality assessment tool for km-scale simulations in the Destination Earth Climate Digital Twin - the diagnostics suite
Authors: Caprioli Silvia , von Hardenberg Jost , Ghinassi Paolo , Ghosh Supriyo , Kluft Lukas , Koldunov Nikolay , Massonnet François , Nazarova Natalia , Nurisso Matteo , Ortega Pablo , Sayed Susan , Sharma Tanvi , Davini Paolo
Published: March 2024

Destination Earth (DestinE) is a major initiative by the European Commission aiming to create a highly accurate global digital twin of Earth. This model, supported by advanced high-performance computing and artificial intelligence, will monitor and simulate interactions between natural phenomena and human activities with unprecedented accuracy. Developed within the Climate Adaptation Digital Twin of the Destination Earth project, AQUA (Application for Quality assessment and Uncertainty quAntification) is a specialized model evaluation framework for running climate data diagnostics.While existing diagnostic suites for global climate model data are already available, AQUA stands out by specifically addressing extensive kilometer-scale datasets, to simplify climate data access for all possible users. AQUA features two diagnostic families:"state-of-the-art” diagnostics, which compare low-resolution data with observations to assess general model performance and to identify biases and drifts (performance indices, radiation budget, atmospheric global mean time series and biases, teleconnection indices, ocean circulation evaluation, tropical cyclones detection, tracking and zoom-in)
“frontier” diagnostics, which exploit new high-resolution (i.e., km-scale hourly) climate data to provide insight at climatological scales of physical/dynamical processes that could not be investigated before (sea surface height variability, tropical rainfall) 
Beyond offering a flexible and efficient framework for processing and analyzing large volumes of climate data, AQUA’s modular design offers the possibility of seamless integration of new diagnostic tools, with plans for further expansion in the future phases of the project.In this contribution, we will introduce the current suite of AQUA diagnostics and outline its planned future developments.
Using field deployable sensors to identify the inter-event predictability of Dissolved Organic Matter mobilisation in an urban river
Authors: Zhu Hongzheng , Khamis Kieran , Hannah David M. , Krause Stefan
Published: March 2024

Emerging sensor technology offers new opportunities to monitor different fractions of Dissolved Organic Matter (DOM) in high resolution. Concentration-discharge (C-Q) relationships (e.g. hysteresis or c-q slopes), derived from high frequency observation can offer insight into source mobilization and reactive transport processes of DOM. However, few studies have explored patterns in urban catchments, where understanding of storm event DOM responses under different hydrometeorological conditions remains elusive. To bridge this gap, we collected 2-years (15 min resolution) fluorescence data (humic-like fluorescence [HLF: Ex. 325 nm/ Em 470 nm] and tryptophan-like fluorescence [TLF: Ex 275 nm/ Em 350 nm]) in an urban headwater stream (Birmingham, UK). We used c-q slopes and two indices, the hysteresis index (HI) and flushing index (FI), to explore the inter-event variability in DOM dynamics. In addition, we assessed the hydrometeorological factors (e.g., antecedent conditions, temperature, discharge and rainfall characteristics) that govern DOM mobilisation and transport using statistical multiple linear regression. Our findings reveal pronounced seasonal variation in the behaviour of TLF and HLF. In warmer periods, the chemodynamic characteristics of both fluorescence peaks become evident. We observed a consistent counter-clockwise hysteresis pattern accompanied by flushing behaviour. The magnitude of discharge, antecedent temperature, and rainfall intensity were identified as key drivers of HLF and TLF flushing and hysteresis dynamics. Conversely, during colder months, a shift in DOM mobilisation was observed. For TLF, source limitation was apparent, characterized by clockwise hysteresis and a notable dilution. In contrast, HLF exhibited a more variability during this period, with complex hysteresis patterns and a combination of solute flushing and dilution. The magnitude of discharge and antecedent wetness were identified as the key factors influencing the solute behaviour in this cooler period. Our research indicates that the responses of DOM in urban rivers exhibit distinct responses to hydrometeorological conditions which were relatively predictable (i.e. low stochasticity within particular event types). However, variability in DOM composition and magnitude was pronounced between event types which has implications for managing urban rivers, specifically ensuring ecological health and resilience are maintained in the face of increasing climatic extremes.
Summer aridity decouples growth from carbon assimilation in temperate oaks
Authors: Rao Mukund Palat , Pacheco-Solana Arturo , Jensen Johanna E. , Li Rong , Griffin Kevin L , Pederson Neil , McCormack Luke M , Verfaillie Joseph , Yang Xi , Baldocchi Dennis , Andreu-Hayles Laia , Oryan Bar , Hise Jeremy , Rodriguez-Catón Milagros , Turner Alex , Eitel Jan , Scanlon Todd M , Pierrat Zoe , Penuelas Josep , Magney Troy
Published: March 2024

Forest biomass resulting from tree radial growth can remain on the landscape over decadal to centennial timescales and plays a critical role in forest carbon cycling. However, visually green vegetation may not be a good proxy for carbon allocation to growth as the phenology and environmental sensitivity of photosynthesis may be different from radial growth. Here we investigate the decoupling between photosynthesis and tree radial growth across intra to interannual timescales for seven North American oak species (Quercus spp.) at four sites (Lamont Sanctuary, NY; Morton Arboretum, IL; Pace Forest, VA; & Tonzi Vaira, CA, USA). Using point dendrometers and wood anatomy, we find that oak trees generally commenced radial growth (cell division and expansion) one month prior to full canopy development and peak carbon assimilation estimated using eddy covariance, satellite and in-situ remote sensing, and leaf-level chlorophyll fluorescence. Further, radial growth was essentially completed by early summer, two to three months prior to the early autumn end of the photosynthetic activity, and before the annual peak in temperature and vapour pressure deficit (VPD) and lowest soil moisture. This suggests that high summer aridity limits carbon allocation to growth more strongly than assimilation. Tree-ring width chronologies for these species across North America further supports that results that earlywood growth depends on prior season climate and assimilated carbon while latewood growth ends by early-summer and responds primarily to current year climate variability. In summary, temporal decoupling between radial growth and photosynthesis and the stronger constraint of summer aridity on growth than photosynthesis appears to be widespread among multiple North American temperate oak species. As summers continue to warm and dry under climate change, this source-sink (or photosynthesis-growth) decoupling needs to be better resolved to constrain forest carbon cycling, as increasing aridity will likely influence the ability of trees to allocate carbon to long-term storage as woody biomass.
Forests on fire: Effects of input data resolution on forest fire behaviour modelling – A case study from Lower Austria
Authors: Kuhnen Katrin , Asensio Maria Isabel , Cascón José Manuel , Iglesias José Manuel , Andrade Mariana Silva , Klisho Tatiana , Formayer Herbert , Vacik Harald
Published: March 2024

Forest fires are becoming an important hazard in the mountain forests of European alpine areas due to changing environmental and socio-economic conditions. Understanding the fire behaviour is critical for all phases within the disaster management cycle – from prevention and preparedness to response and recovery. PhyFire is a simplified physical model which simulates the fire propagation and allows considering fire suppression measurements to see their effect on the fire behaviour. The model has been used for Mediterranean countries so far but has been now adapted to central European alpine mountain forests within this case study. The model requires the following input data: a digital height model, fuel data, and meteorological data. Besides the adaption process itself the effect of different qualities of input data in terms of temporal and spatial manner were investigated. In this contribution we show the challenges of the adaption process of the PhyFire model to the characteristics of the Austrian case study area and analyse the effect of different resolutions of input data resolution on the overall quality of the fire propagation simulation.
Using a colloidal borescope to define groundwater flow directions at contaminated sites 
Authors: Rodighiero Michele , Sottani Andrea , Buggiarin Stefano , Vettorello Luca
Published: March 2024

Detailed knowledge of the groundwater flow field is one of the fundamental technical prerequisites for designing effective remediation measures for contaminated aquifers.The environmental issues under discussion concern both the implementation of emergency measures, commonly carried out by means of Pump&Treat (P&T) hydraulic containment systems, and remediation actions, developed through the adoption of in-situ technologies and treatments.In hydrogeological practice, the analysis of groundwater flow directions is implemented on a piezometric basis, reconstructing the water table trend from point-level measurements. These point measurements are appropriately interpreted using geostatistical contouring algorithms.However, within a single contaminated site, very specific circumstances may be found, due to both natural and operational reasons or other logistical challenges. The first group includes intrinsic geological factors, which derive e.g. from depositional mechanisms: typically, saturated alluvial systems are characterized by structural heterogeneity and anisotropy that can sometimes influence the design choices for remediation. Similarly, the geometry of the site and the presence of structures in relation to the position of the contamination source and the direction of groundwater flow can influence the location of interventions and installations, such as the position of pumping and monitoring wells, the latter placed behind the hydraulic barrier to verify its effectiveness.In these environmental contexts, a methodological in-depth study is underway, aimed at combining traditional hydrogeological parameterization techniques with an advanced experimental measurement system with colloidal borescope.The borescope is an optical device capable of following the movement of colloids in monitoring wells: field observation of the motion of these particles shows that the directional measurements, in addition to being generally consistent with the expected flow field, also provide complementary point-based results compared to those achievable with traditional techniques (Kearl, 1997). The instrument detects the flow of colloids from stagnant conditions up to flow rates close to 3 cm/s, allowing the prevailing azimuthal direction of transport to be established using statistical criteria.This work describes the preliminary results of unpublished measurements, carried out in contaminated aquifers controlled by hydraulic barriers in operation. The results achieved to date suggest the opportunity for the use of the colloidal borescope to refine the conceptual hydrogeological model in contaminated sites even in dynamic regime situations.
A real options-based decision-making framework for hydraulic infrastructure investments
Authors: Rezazadehkhorasani Hamidreza , Tilmant Amaury
Published: March 2024

Planning hydraulic infrastructure is challenging as it requires the careful consideration of many uncertain factors, such as the evolution of future demands and supplies. The deep uncertainty attached to climate change makes traditional planning approaches based on well-characterized statistical distributions ill-suited. This has led to the emergence of a new paradigm, "prepare and adapt," which focuses on developing robust and adaptive systems that can perform well under a wide range of futures. This research presents a framework for planning new water resources infrastructure (e.g., reservoirs, hydropower plants) based on real options, deep uncertainty, and temporal multicriteria analysis (TMCA). The real option component essentially handles the issues associated with the timing, sequencing, sizing, and operating of those infrastructures. The deep uncertainty that characterizes future hydroclimatic conditions is captured by a large ensemble of GCM-based hydrologic projections. Finally, TMCA allows us to compare and rank the options with respect to several criteria reflecting the different water uses (e.g., irrigated agriculture, hydropower generation, navigation, fisheries, flood recession agriculture, municipal and industrial water supply) in a dynamically changing environment induced by both climate change and the options. The framework is applied to the Senegal River Basin (SRB) in West Africa. The SRB is a complex system with several planned hydropower projects and irrigation schemes, making it ideal for testing the proposed framework. The results identify development pathways associated with different tradeoffs between risk and reward.  The framework also helps decision-makers understand the distributional effects of these development pathways on society.
Accurate Long Term Height Determination at SLR Stations
Authors: Dunn Peter , Husson Van , Szwec Christopher
Published: March 2024

Recent advances in SLR data analysis are described in ‘The ILRS contribution to ITRF2020’, Pavlis and Luceri (2022). Improved vertical resolution can now complement the more easily resolved horizontal motion. We examine the emerging results from ITRF2020 and prioritize the most accurate geodetic products. Height variations at SLR stations in tectonically stable regions of Australia and North America exhibit steady and consistent height rates.  Robust long-term vertical motion models also enable precise monitoring of behavior at higher frequencies: annual, tidal, and diurnal. Tracking operation procedures have been implemented to reduce and monitor ranging measurement accuracy. Comparisons of the vertical signals in SLR, VLBI, DORIS and GNSS systems allow robust accuracy monitoring at co-located stations. Data handling techniques are outlined to enhance the isolation of the geodetic signals and enable their application to Earth and Ocean Model development 
How do supercritical turbidity-current bedforms transition? Insights from seismic data interpretation in the South China Sea
Authors: Wang Biwen , Zhong Guangfa , Wang Liaoliang , Kuang Zenggui
Published: March 2024

The transition of supercritical turbidity-current bedforms has been studied in the flume experiments and outcrops, whereas similar bedform transitions in deep-sea cases are rare. To better understand the mechanism behind bedform transitions in natural environments, we investigated the tempo-spatial transition of supercritical turbidity-current bedforms in the lower continental slope to abyssal plain in the northeastern South China Sea, by high-quality single-channel seismic data analysis coupled with simple numerical modeling. Quaternary bedforms were delineated at >3400 m water depth, covering an area of ~20000 km2. These bedforms are characterized by long wavelength (0.4-5 km), low wave height (1-15 m), and large aspect ratio (80-730), which are identified as supercritical-flow bedforms. Four types of bedforms were further identified based on the morphology and internal structure, which are (I) upslope-migrating cyclic steps characterized by asymmetrical morphology with thick backsets and long wavelength; (II) upslope-migrating antidunes (UMAs) featured by nearly symmetrical morphology and relatively short wavelength; (III) downslope-migrating antidunes (DMAs) typified by gentle and sigmoid foresets and large aspect ratios; (IV) upper-stage plane beds (UPBs) consisting of low-relief wavy to subhorizontal reflections. Slope variations are highlighted to induce flow energy changes and facilitate bedform transitions. A slight slope decrease from 0.5 to 0.1° and 0.3 to 0.1-0.2° would respectively lead to the transition from UMAs to UPBs and from cyclic steps to UMAs, due to the hydraulic jump and flow acceleration. In contrast, an increased slope from 0.1 to 0.2° can contribute to the transition from UMAs to cyclic steps or DMAs by re-accelerating flows. Over time, the bedforms evolve from DMAs to UMAs and cyclic steps with growing wavelengths and wave heights, possibly caused by the inherited development of bedforms and increasing aggradation rates linked with progressively rising Taiwan uplifting rates. These bedforms consist of three contiguous fields fed by inter-seamount pathways and Manila Trench, comprising a supercritical-flow submarine fan apron that is far from the shelf edge and lacks submarine channels. This research was supported by the National Key Research and Development Program of China (Grant Number 2022YFF0800503).
Magma Accommodation and Ground Movement Analysis: testing the reliability of analytical volcano deformation models 
Authors: Magee Craig , Ebmeier Susanna
Published: March 2024

Space for magma intrusion in the subsurface is often created by uplifting and bending of overlying rock, producing a forced fold. This intrusion-induced forced folding can deform the free surface, driving ground movement at active volcanoes. Monitoring such ground movement using satellite- and ground-based instrumentation plays a key role in volcanic eruption forecasting. Specifically, modelling ground movement allows us to assess eruption threats, by estimating intrusion properties (e.g., geometry, depth, volume, and pressure), and understand of volcanic system evolution and behaviour. Yet building accurate ground movement models to reliably estimate intrusion properties requires knowledge of a volcano’s subsurface composition and structure; information which is often limited or unavailable. Many ground movement models therefore tend to use analytical or numerical approaches that embed simple intrusion geometries within a homogeneous, isotropic, and linearly elastic medium (i.e., a material of uniform composition and structure). To assess the reliability and validity of such ground movement models, it would thus be beneficial to identify scenarios where known and modelled intrusion properties can be confidently compared.Seismic reflection data image Earths subsurface in 3D at metre- to decametre-scale resolutions and can thus capture the detailed geometry of ancient intrusions and overlying forced folds. Where such intrusion-fold pairs have been seismically imaged, these data show: (1) intrusion geometries are typically complex; (2) host stratigraphic sequences comprise multiple lithologies; and (3) forced fold amplitudes are often less than intrusion thicknesses, implying space for magma was generated by both uplift and internal fold deformation (e.g., compaction). Importantly, seismic reflection data uniquely allow us to measure and model syn-emplacement ground movement driven by forced folding, whilst independently determining the geometry, size, and depth of underlying intrusions. Here, we examine an Early Cretaceous laccolith and forced fold pair imaged in 3D seismic reflection data from the Exmouth Plateau, offshore NW Australia. We consider how post-emplacement, burial-related compaction has reduced the fold amplitude by using local borehole data, which describe the lithology and seismic velocity of the folded strata, to decompact the succession and recover estimates of the original fold geometry. From these estimates of the original fold geometry, we calculate possible vertical and horizontal displacement components of deformation; this displacement data can be considered akin to that acquired during monitoring of ground movement at active volcanoes. By applying standard analytical methods to estimate intrusion properties from this pseudo-ground movement data, we compare model outputs to the true location, geometry, and size of the seismically imaged intrusion.
Temporal evolution of basal terraces at Ekström Ice Shelf, East Antarctica 
Authors: Drews Reinhard , Oraschewski Falk , Ershadi M. Reza , Hawkins Jonathan , Wild Christian , Schlegel Rebecca , Koch Inka , Zeising Ole , Eisen Olaf
Published: March 2024

Ekström Ice Shelf is a representative ice shelf for the ice-shelf belt of the Dronning Maud Land Coast in East Antarctica. It has cold ocean-cavity with moderate basal melt rates averaging a few meters per year across the ice shelf. In spite of the comparatively small average basal melt rates, we find basal terraces in a ground-penetrating radar dataset revealing near-vertical walls of more than 30 meters height. Such features have also been observed  elsewhere and linked to large localized basal melt rates which is in parts oriented in the horizontal direction. Here we use a ground-penetrating radar dataset with a profile spacing of
Bioaerosol and Atmospheric Simulation Chamber: first studies on bacteria viability versus NOx concentrations.
Authors: Gatta Elena , Abd El Elena , Brunoldi Marco , Irfan Muhammad , Isolabella Tommaso , Massabò Dario , Mazzei Federico , Parodi Franco , Prati Paolo , Vernocchi Virginia
Published: March 2024

Bioaerosol is generally defined as solid airborne particles of biological origin suspended in the gaseous medium ubiquitously with an aerodynamic diameter of up to 100 µm. They can either be naturally released from the biosphere to the atmosphere or are released due to human activities. Here, we present the results of several experiments, performed inside a confined and controlled artificial environment, such as the Atmospheric Simulation Chamber, providing valuable information on bio-aerosol viability, dispersion, and impact. At ChAMBRe (Chamber for Aerosol Modelling and Bio-aerosol Research), managed by INFN at the Physics Department of the University of Genoa, Italy, the research on bioaerosol is focused on the investigation of the airborne bacteria behavior in different atmospheric and air quality conditions (Massabò et al., 2018). A multi-step protocol was developed (Vernocchi et al, 2023) and thoroughly tested to cultivate a suitable bacteria population (E. coli, B. subtilis, B. licheniformis, and P. fluorescens). Then, bacteria are nebulized, and injected inside ChAMBRe, where they are exposed to different gas concentration values. The viability variation, due to the pollutant exposure inside ChAMBRe, was determined by monitoring the concentration of viable bacteria. The bacteria survival rate inside ChAMBRe is first evaluated by a set of baseline experiments (clean air condition) and successively exposing the bacterial strands to NO2 and NO concentration values up to 1200 ppb for both pollutants. A WIBS-NEO instrument measured bacteria total concentration inside ChAMBRe while the viable concentration was determined by active sampling on Petri dishes by an Andersen impactor and then counting the Colonies Forming Units (CFU). In addition, a liquid impinger was used to maintain the integrity of the microorganisms and their physiological state to investigate a sampling strategy to assess viability and simultaneously cultivability, taking into account the VBNC status (viable but not cultivable).  To this end, we present the results of impactor experiments and preliminary assessments with live and dead assays examined by fluorescence microscopy for quantitative and qualitative analysis.ReferencesMassabò, D., Danelli, S. G., Brotto, P., Comite, A., Costa, C., Di Cesare, A., Doussin, J. F., Ferraro, F., Formenti, P., Gatta, E., Negretti, L., Oliva, M., Parodi, F., Vezzulli, L., and Prati, P.: ChAMBRe: a new atmospheric simulation chamber for aerosol modelling and bio-aerosol research, Atmos. Meas. Tech., 11, 5885–5900, https://doi.org/10.5194/amt-11-5885-2018, 2018.Vernocchi, V., Abd El, E., Brunoldi, M., Danelli, S. G., Gatta, E., Isolabella, T., Mazzei, F., Parodi, F., Prati, P., and Massabò, D. (2023) Atmos. Meas. Tech., 16, 5479–5493. https://doi.org/10.5194/amt-16-5479-2023, 2023.
The asymmetry towards stronger Birkeland currents in the Northern Hemisphere
Authors: Coxon John , Vines Sarah , Milan Steve , Anderson Brian
Published: March 2024

Iridium satellites in low-Earth orbit have transformed our knowledge of geospace by enabling the AMPERE dataset. We employ AMPERE data from October 2009 to December 2021 to examine the interhemispheric asymmetry in Birkeland currents over the span of a solar cycle. We take daily averages of the upward and downward current in both hemispheres and examine the systematic asymmetry by removing the seasonal trend. We find that Birkeland currents are stronger in the Northern Hemisphere than in the South after removing the seasonal trend, consistent with Coxon et al. (2016). We explore how this asymmetry manifests over a solar cycle and compare the variation of the asymmetry to other parameters.
Understanding the association between global teleconnections and concurrent drought and heatwaves events over India
Authors: Das Bhowmik Rajarshi , Tabbussum Ruhhee , Mujumdar Pradeep
Published: March 2024

The variability in the occurrence of concurrent extremes like droughts and heatwaves is often attributed to climate change and anthropogenic factors, neglecting its connection with large-scale global teleconnections. The current study investigates the temporal and spatial connections between concurrent droughts and heatwaves (CDHW) in India to large scale global teleconnections like El Nino Southern Oscillation, North Atlantic Oscillation, Pacific Decadal Oscillation, and Indian Ocean Dipole. Utilizing composite and wavelet coherence analyses, we conduct a univariate assessment of droughts and heatwaves, quantified with the standardized precipitation index and standardized heat index, respectively, in association with large-scale global teleconnections (referred as climate drivers). Further, a novel attribution table framework proposed to quantify the conditional probability of CDHW given the onset of climate drivers. We found that the probability of CDHW preceeding the onset of climate drivers is much higher compared to the probability of CDHW occuring without the onset of climate drivers. The insights from this study suggest the potential use of global teleconnections for issuing season-ahead forecasts of CDHW.
Deep ocean hydrographic heterogeneity inferred from offshore geodetic experiments
Authors: Jegen Anna , Lange Dietrich , Karstensen Johannes , Pizarro Oscar , Kopp Heidrun
Published: March 2024

Observational evidence, supported by high resolution numerical model simulations, indicate that meso- and submesoscale dynamics exists in the deep ocean (>2000m). However, over most parts, observing the deep ocean is restricted to address either spatial but not temporal (ship surveys) or temporal but not spatial (moored sensors) scales of variability. The advent of a growing number of offshore geodesy experiments, conducted with networks of distributed sensor arrays, aiming to evaluate tectonic deformation through strain measurements can potentially provide new ways to observe deep sea hydrographic variability. Despite the different observing objectives of offshore geodetic and oceanographic experiments, a great overlap in the measured parameter space exists, which has motivated analyses exploring possible cross-benefits. Here we present the evaluation of temperature, pressure, and sound speed observations from a 2.5-year offshore geodesy experiment centered along the northern Chilean subduction zone (~21.5°S and ~71.5°W to ~70.5°W). Our analysis confirms multi-year warming trends that previous studies have reported for the deep ocean but shows an additional regionalization of warming trends. Superimposed onto the multi-year warming trend are temperature fluctuations that show multi-hourly to multi-weekly periods and amplitudes that show both spatial and depth/regional dependencies. Aside from a general decrease in energy levels of the fluctuations with depth, we see evidence of ocean-topography interactions through barotropic topography waves. Taken together, the observations reveal de-coupled dynamical regimes seaward and landward of the deep-sea trench that mark the extent of the abyssal part of the eastern boundary current off Chile and demonstrate the potential of time series from offshore geodetic surveys for hydrographic analyses.
Seismic 3D imaging at the Bedretto Underground Laboratory (Switzerland): active seismic cross-hole tomography using fat rays
Authors: Schwarz Miriam , Maurer Hansruedi , Obermann Anne , Wiemer Stefan ,   BedrettoLab Team
Published: March 2024

The Bedretto Underground Laboratory for Geosciences and Geoenergies (BedrettoLab), operated by ETH Zurich, is a unique research facility providing optimal conditions for conducting experimental research on understanding the responses of the deep underground when stimulating it. Our experiments were performed in a Geothermal Testbed in the BedrettoLab. It includes six monitoring boreholes, ranging from 250 to 400 m length. They are equipped with multiple instruments including seismic sensors (geophones, accelerometers and acoustic emission) and active seismic sources (piezoelectric transducers). In addition, two stimulation boreholes are used to access the underground. A fault zone is crossing the boreholes in the volume of interest, which is one of the main targets of our investigations.Advanced knowledge of the spatial distribution of the seismic velocities (i.e. elastic properties) is essential for several purposes, including, for example, geological and geotechnical characterizations of the rock volume, locating microseismicity caused by the hydraulic stimulations, and performing active seismic monitoring experiments. For that purpose, we have compiled a comprehensive active seismic travel time data set. As seismic sources we considered borehole sparker shots and the permanently installed piezoelectric transducers. The seismic waves were recorded with hydrophone streamers and the permanently installed seismic sensors. This resulted in roughly 45’000 travel time picks.Here, we present first results of a 3D P-wave velocity tomography. Even with this relatively large data set, the ray coverage within the volume of interest is still relatively incomplete, when using classical (infinitesimally thin) rays. Therefore, we considered a fat ray approach, with which the finite bandwidth of seismic waves can be approximated more realistically. We will compare the classical ray-based tomography (high frequency approximation) with results from the fat ray tomography (frequency dependent). The resulting tomograms can be compared with borehole image logs.
Foraminifera nitrogen isotopes and body size reveal an oxygen rise in the tropical upper ocean during the Paleocene-Eocene Thermal Maximum (PETM)
Authors: Moretti Simone , Auderset Alexandra , Deutsch Curtis , Schmitz Ronja , Gerber Lukas , Thomas Ellen , Luciani Valeria , Petrizzo Maria Rose , Schiebel Ralf , Tripati Aradhna , Sexton Philip , Norris Richard , d'Onofrio Roberta , Zachos James , Sigman Daniel , Haug Gerald , Martínez-García Alfredo
Published: March 2024

Ocean’s oxygen (O2) is essential to most marine life forms and represent a fundamental component of the biogeochemical cycling of nitrogen and carbon. Its inventory is declining in response to global warming. Contrasting predictions about the future of the tropical oxygen deficient zones (ODZs) in numerical simulations and palaeoceanographic evidence for contracted ODZs during Cenozoic’s warmest periods, make long-term predictions about the future of ocean O2 challenging. We present new evidence for tropical ocean oxygenation during the Paleocene-Eocene Thermal Maximum (PETM), a rapid warming event that serves as a geologic analogue to ongoing warming. Foraminifera-bound nitrogen isotopes indicate that the tropical North Pacific ODZ contracted during the PETM, implying higher O2. Metabolic modelling of aquatic ectotherms shows that a concomitant increase in planktic foraminifera size implies that seawater oxygen partial pressure (pO2) rose in the shallow subsurface throughout the tropical North Pacific, beyond the spatial extent of the ODZs. These findings call for an oceanographic mechanism capable of both enhancing subsurface oxygenation and operating beyond the regional scale of the North Pacific ODZs, on millennial timescales. These divergent changes are consistent with Ocean General Circulation Models under SSP5-8.5 scenario for 2300, in which a decline in biological productivity allows tropical subsurface oxygen to rise even as global ocean oxygen declines. The tropical upper ocean oxygen increase may have relieved physiological stress, helping to avoid a mass extinction in planktic organisms during the PETM, in spite of the largest benthic extinction of the Cenozoic.
Biogenic sulfur compounds and their oxidation products in the spring-to-summer Arctic marine atmosphere
Authors: Willis Megan , Zang Cort , Asplund Julia , Mattsson Fredrik , Zieger Paul , Tjernström Michael
Published: March 2024

Gas-phase biogenic organosulfur compounds, and their oxidation products are important for the formation and growth of aerosol in the marine environment. During the spring-summer increase in marine biological activity in the northern hemisphere, dimethyl sulfide ((CH3)2S, DMS) and methanethiol (CH3SH, MeSH) are emitted from ocean and sea-ice environments. The emission or transport, and following oxidation, of organosulfur compounds to the Arctic marine environment impacts the available aerosol number and cloud condensation nuclei. Here, we examine organosulfur compound composition, atmospheric fate, and relationships to the aerosol population at the onset of sea-ice melt.We present shipborne gas-phase measurements of reduced and oxidized organosulfur compounds made with a H­3O+/NH4+ reagent ion switching chemical ionization time-of-flight mass spectrometer as part of the Atmospheric Rivers and the onseT of sea ice MELT (ARTofMELT) campaign on IB Oden. Our measurements during ARTofMELT spanned from May 7th to June 15th of 2023 and took place over pack ice and the marginal ice zone between 78 and 81°N between the east coast of Greenland and the Svalbard archipelago (the Fram Strait). Non-DMS organosulfur species made a significant contribution to atmospheric sulfur during the campaign. MeSH was present at concentrations ~10% of DMS (10’s of pptv) during periods of elevated organosulfur compounds (DMS exceeding ~100 pptv) and was correlated with DMS (R2 > 0.8). Ambient temperatures ranged between -15 and 2°C, making the primary oxidation reaction between DMS and the hydroxyl radical the OH-addition pathway to produce dimethyl sulfoxide (DMSO). We observed DMSO in concentrations occasionally exceeding 150 pptv, and the chemical formula C2H6SO2 (likely dimethyl sulfone) at similar concentrations to DMSO. During low ozone periods (< 10 ppbv), the loss of DMS was potentially influenced by halogen chemistry resulting in an increased abundance of DMSO relative to DMS. We use our measurements to investigate organosulfur compound composition and loss pathways under a variety of atmospheric conditions.
Does a mineral soil coverage reduce greenhouse gas emissions from agriculturally managed peatlands?
Authors: Paul Sonja , Ammann Christof , Wang Yuqiao , Alewell Christine , Leifeld Jens
Published: March 2024

The agricultural use of organic soils usually requires drainage, resulting in soil subsidence and high greenhouse gas (GHG) emissions, particularly CO2. One proposed strategy to maintain the productivity of these soils is applying a mineral soil cover. However, the impact on the overall GHG budget is unknown. Herein, we determined the net ecosystem carbon budget (NECB) for a pair of covered (Cov) and uncovered (reference, Ref) organic soils under intensive grassland management in the Rhine Valley, Switzerland, over four years (1 March 2018–29 February 2022). The net ecosystem exchange (NEE) of CO2 fluxes was measured using the eddy covariance method, in addition to recording additional carbon exports and imports for harvest and organic fertilisers. N2O and CH4 fluxes were measured using an automatic time-integrating chamber system over three years. Both of the drained peatlands under agricultural use showed substantial soil organic carbon (SOC) losses of 6.5 to 28.9 t CO2 ha- 1 year -1 (Ref) and 4.6 to 30.3 t CO2 ha- 1 year -1 (Cov), driven by the aerated peat carbon stock during summer and accounting for 1.4 %–0.5 % of the total aerated carbon stock. Covering the organic soil with a mineral layer did not significantly reduce the SOC losses relative to the reference site in any of the four years at either site, and CH4 uptake was marginal. However, soil coverage reduced the contributions of N2O to total GHG emissions from 28 % (Ref) to 7 % (Cov). Thus, we conclude that mineral soil coverage per se has little potential to reduce carbon losses from drained organic soils. However, if combined with a considerable rise in the water table, SOC losses may be effectively reduced while maintaining agricultural productivity.
Upper-mantle velocity structures and anisotropy under the Mongol-Baikal region
Authors: Wu Hanting , Huang Zhouchuan
Published: March 2024

The Mongol-Baikal region is located in the western segment of the Central Asian Orogenic Belt. This area experienced multiple periods of extensive compression starting from the Proterozoic. In the Cenozoic, the study region was modified by neotectonics, featuring large extensional rifting (the Baikal rift zone) and plateau uplift (the Hangai Dome). However, the deep mechanisms of the onset of rifting and doming are still debated. We performed high-resolution 3-D P-wave tomography under the southwestern Baikal and western Mongolia. The images show distinct low-velocity anomalies under the Baikal Rift at ~60 km depth, the Hangai Dome at ~200 km depth, and beneath the Siberian craton. This may indicate that potential mantle flows ascended from the deep Siberian MTZ to shallower levels, influencing the rifting of the Baikal rift zone and the lithospheric process of the Hangai Dome. We then further determined the seismic anisotropy of the upper mantle under western Mongolia using SKS splitting measurements. The study region is dominated by NW-SE trending fast polarization directions (FPD), which indicates consistent compressional and transitional stress among the whole study area. Small delay times in the Hangai Dome spatially coincide with the low-velocity anomalies, supporting remarkable asthenosphere upwelling. However, the local Hangai upwelling did not affect the general anisotropic structures significantly, indicating that the lithospheric process only occurred in a limited area.ReferencesWu, H., Huang, Z., 2022. Upper mantle anisotropy and deformation beneath the western Mongolian Plateau revealed by SKS splitting. Tectonophysics 835, 229376. https://doi.org/10.1016/j.tecto.2022.229376Wu, H., Huang, Z., Zhao, D., 2021. Deep structure beneath the southwestern flank of the Baikal rift zone and adjacent areas. Physics of the Earth and Planetary Interiors 310, 106616. https://doi.org/10.1016/j.pepi.2020.106616 
Attention-based postprocessing of ensemble weather forecasts for renewable energy applications by leveraging inter-ensemble relationships of multiple predictors
Authors: Van Poecke Aaron , Meng Ruoke , Demaeyer Jonathan , Van den Bergh Joris , Smet Geert , Termonia Piet , Hellinckx Peter , Tabari Hossein
Published: March 2024

Indirect models for renewable energy forecasting rely heavily on accurate weather predictions. Operational weather forecasting today is mainly based on numerical weather prediction models, often employing ensembles to estimate the day-to-day forecast uncertainty. To correct for errors due to simplifications in these models, inaccurate initial conditions, and representativeness problems, statistical postprocessing becomes necessary for these ensemble forecasts. Current postprocessing techniques often disregard possible inter-ensemble relationships by correcting each member separately, or employ a distributional approach that requires extra multivariate methods to restore spatio-temporal and inter-variable correlations. In this work, we tackle these shortcomings with an innovative, attention-based member-by-member approach which postprocesses each member individually while simultaneously integrating information from other ensemble members. Variables required for renewable energy forecasting are postprocessed at the station level by regressing ensemble forecasts of multiple predictors, including the forecasted variable itself, against observational data. The training data utilized is sourced from the EUPPBench dataset, which contains ensemble predictions from the integrated forecasting system of the ECMWF and corresponding observations. Transformer modules built around Self-Attention are employed to capture dependencies between different predictors, such as temperature and total cloud cover, next to significant relationships between the ensemble members themselves. Additionally, our model postprocesses the forecasts for all lead times simultaneously, taking into account the correlation between the postprocessed variable and  forecasts generated at earlier and later lead times. This results in postprocessing techniques that can be employed in downstream applications for conversion to renewable energy forecasts.
Microplastic Contamination in Groundwater Aquifers along the Ganga River Basin: A Comprehensive study from Devprayag to Gangasagar, India
Authors: Chaudhary Nidhi , Maurya Abhyanand Singh
Published: March 2024

Microplastics are tiny plastic particles, less than 5 millimetres in size and their access to food chain have a significant hazard to ecosystems and environmental health. Their concern also extends to drinking water and our limited understanding of their occurrence in groundwater aquifers poses a potential research gap. Our preliminary investigation suggests the presence of microplastics in groundwater samples from near vicinity of Ganga Channel and subsequently, 60 groundwater samples were collected for the detailed study from Devprayag (Uttarakhand) to Gangasagar (West Bengal), India. This is the first study that investigates the distribution and quantification of microplastics from the groundwater aquifers influenced by Ganga River water, the largest fresh water source in Northern India. The water samples are filtered through 0.45-micron size nitrocellulose filter membrane and the residue is visually inspected under a stereo microscope. Further, the abundance, type, and size of MPs were determined by micro-Raman spectroscopy following a well-established and quality-controlled analytical route. The findings indicate the presence of microplastics (MPs) in all samples, with Polyethylene (PE), Polypropylene (PP), and Polyvinyl chloride (PVC) identified as common types in each sample. Various shapes of microplastics, such as fibres, fragments, films, and foam, were detected. MPs with size less than 150 µm are significantly abundant, likely owing to their mixing in ground water through the infiltration from surface waters. Contamination of groundwater with microplastics (MPs) poses a significant health risk, especially given its importance as a crucial source for drinking and irrigation. If this problem left untreated or if concentrations of MPs continue to rise, this has the potential to evolve into a man-made disaster.
Inconsistencies of signatures of Eurasian heat waves in the large-scale Rossby waves in CMIP models
Authors: Strigunova Iana , Blender Richard , Lunkeit Frank , Žagar Nedjeljka
Published: March 2024

This study identifies discrepancies in signatures of the Eurasian heat waves (EHWs) in the reanalyses and climate models. The scale-dependent analysis considers the global Rossby wave spectrum for the extended boreal summer using daily values of the Rossby wave mechanical energy. We filter Rossby waves using a multivariate, 3D projection of the horizontal velocity and geopotential fields onto a set of orthogonal normal-mode functions. Our previous study has found that Rossby wave energy follows a χ2-distribution with skewness related to the number of degrees of freedom. During EHWs, the skewness of the normalised energy anomaly distributions increases with a corresponding decrease in the number of active degrees of freedom, implying fewer modes involved. Fewer modes indicate a blocking structure that is identified as an increase in the Rossby wave amplitude in the middle troposphere during EHWs. Here, we compare the spatial structure and energy distributions of the troposphere-barotropic Rossby waves in the subset of CMIP5 models with findings from reanalyses. The increase in planetary Rossby wave amplitudes is first identified for the present-day climate. Significant differences among the models are found regarding the change in the skewness of the Rossby wave energy distribution and hence the number of active degrees of freedom during EHWs. The results highlight inconsistencies in simulating the day-to-day variability of planetary Rossby waves during EHWs in the CMIP models despite the overall agreement in the mean circulation and EHW metrics based on surface data reported in previous studies. The results of this study have potential implications for the interpretation of projected changes in Rossby waves and EHWs in future CMIP climate simulations. 
The story of double spreading centers formed during continental rifting in 2D
Authors: Le Pourhiet Laetitia , Zhou Fan
Published: March 2024

It is common wisdom, based on many years of published simulations of continental rifting followed by spreading that in 2D when a mid-oceanic ridge form in a numerical simulation of continental rifting, extension stops and spreading take over the extension. This is generally due to the complete loss of strength of the mantle lithosphere that cannot transmit forces horizontally across the spreading zone anymore. Actually, in general even the onset of mantle lithosphere necking in a simulation can cause the end of the extension and for many years, I actually claimed very load in the past that two active necking system must be the signature of some obliquity causing 3D extensional conditions. However, recently, a whole series of 2D simulations produced systematically two spreading centers active at the same time. These results surprised me a lot. These simulations were very complex, including a lot of inheritance, the first easy conclusion could have been to say that inheritance causes multiple spreading… But we spent some time and effort to understand if this behavior was due to inheritance or something else. Simplifying our model set-up to the strict minimum, we found it was not inheritance, but a quite cold mantle temperature which permitted a larger shear coupling between the upper mantle dynamics and the mantle lithosphere.  A 50°C difference in mantle temperature radically change the results of the simulation and thanks to our failure, we have found the embryo of an alternative explanation to 3D interactions for the occurrence multiple active necking zones.