bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of machine learning to hydro-acoustic seismic and magmaticevents detections
Authors: Raumer Pierre-Yves , Bazin Sara , Cazau Dorian , Ingale Vaibhav Vijay , Lavayssière Aude , Royer Jean-Yves
Published: February 2023

Hydrophones arrays have proven to be an efficient and affordable method to monitor underwater soundscape, in particular magmatic and tectonic events. Indeed, thanks to the sound fixing and ranging (SOFAR) channel in the ocean, acoustic waves undergo a very low attenuation over distance and thus propagate further than they would do across the solid Earth. The MAHY array, composed of four autonomous hydrophones, has been deployed off Mayotte Island since October 2020. It contributes to monitor the recent volcanic activity around the island, and enabled to detect short and energetic acoustic events sometimes reffered to as impulsive events. As for their cause, it has been proposed that these signals are generated by water-lava interactions on the seafloor. So far, these events have been searched by visually inspecting the data, which is a cumbersome and somewhat observer-dependent task. To face these issues, we have developped an automatic picking algorithm tailored for these impulsive events. After some initial signal processing, a supervised neural network model was trained to detect such signals, which can be later checked by a human operator. Taking advantage of the genericity of this detection framework, we applied it to other hydroacoustic data sets (OHASISBIO and IMS-CTBT) to explore the feasibility of detecting T-wave generated by submarine earthquakes. The next step will be to improve the model with unsupervised or semi-supervised feature learning, in order to improve our metrics and, in the end, facilitate the study of specific acoustic signals.
Measuring the Net Charge Density of Space Plasmas
Authors: Shen Chao
Published: February 2023

Space plasmas are composed of charged particles that play a key role in electromagnetic dynamics. However, to date, there has been no direct measurement of the distribution of such charges in space. In this study, three schemes for measuring charge densities in space are presented. The first scheme is based on electric field measurements by multiple spacecraft. This method is applied to deduce the charge density distribution within Earth’s magnetopause boundary layer using Magnetospheric MultiScale constellation (MMS) 4-point measurements, and indicates the existence of a charge separation there. The second and third schemes proposed are both based on electric potential measurements from multiple electric probes. The second scheme, which requires 10 or more electric potential probes, can yield the net charge density to first-order accuracy, while the third scheme, which makes use of seven to eight specifically distributed probes, can give the net charge density with second-order accuracy. The feasibility, reliability, and accuracy of these three schemes are successfully verified for a charged-ball model. These charge density measurement schemes could potentially be applied in both space exploration and ground-based laboratory experiments. 
Mineralization potential from vein statistics at regional scale – an example from the Dharwar Craton (Southern India)
Authors: Biswas Santu , Mamtani Manish A.
Published: February 2023

Hydrothermal veins can form when pre-existing anisotropy gets dilated by increase in fluid pressure (Pf). In addition fluctuation in Pf can result in the deposition of economically important deposits, such as gold in veins. Therefore, statistical analysis of dilational quartz veins can help to identify the mineralization potential of an area. This present study is focused on this aspect. The metavolcanic rocks of Dharwar Craton (Southern India) are replete with quartz veins, but mineralization is restricted to certain domains in the vicinity of Gadag, Hutti, and Kolar. To study the topological importance in mineral exploration, an experiment is carried out in different parts (e.g., Gadag, Hutti, Raichur, Gadwal) of Dharwar Craton. Orientation of dilational quartz veins, thickness, and spacing data are collected from different transects of the above-mentioned areas. Variations in driving pressure ratio (ΔRʹ), fractal dimension (Dc), Weibull modulus (α), vein intensity (Vi), and coefficient of vein spacing (Cv(S)) are calculated from vein data of each transect. These parameters are integrated to plot a three-axes “mineralization potential plot”, also known as P-D-F plot (Lahiri et al., 2020). The distance between the origin (0,0,0) and the point representing the transect in the P-D-F plot gives the “mineralization potential parameter” (Md). It is established that a transect in mineralized zone is represented by a point that lies closer to origin than non-mineralized zone. However, it is our observation that the points representing mineralized zone show more clustering on the P-D-F plot, whereas the points representing non-mineralized zone are dispersed.  We infer that in order to identify a zone as having high mineralization potential, the Md value should not only be lower but also the clustering should be higher.
Study on Hydraulic Resistance Damage Law of External Liquid Intrusion in Tight Sand Conglomerate Reservoir
Authors: Wu Jianbang , Yang Shenglai , Li Qiang
Published: February 2023

In geological resource exploitation engineering such as reservoir development, the intrusion of foreign liquid will cause water lock damage to the formation rock structure, which affects the effect of reservoir transformation such as CO2 sequestration. The tight sand conglomerate reservoir is characterized by high content of expansive clay minerals, high capillary pressure, small pore throat, and serious heterogeneity, which leads to serious water lock damage. The extent, mechanism and reasonable prediction of damage are the concerns of the engineering community.In view of this problem, this study uses the laboratory long core experiment method based on nuclear magnetic resonance (NMR) monitoring to simulate and study the reservoir damage law before and after the invasion of foreign liquid into the formation. The damage distance of liquid resistance and influencing factors were studied, and a prediction model was established. The long core experiment used drilled natural cores with a total length of 45 cm that were spliced from short cores with a diameter of 2.5 cm. A total of five pressure points were set up at 10 cm intervals to monitor the pressure gradient. The pressure gradient changes along the long core after saturated oil and water intrusion were tested separately. A new method of calculating the range and degree of water lock damage zone based on pressure gradient was established. According to the damage control factors obtained from the experimental study, the prediction model of water lock damage with the transformation from multiple nonlinear problems to linear problems is established by using permeability, porosity and content of water-sensitive clay minerals as input conditions.The results show that the physical property of reservoir plays a decisive role in the damage distance of liquid resistance. The foreign liquid intrudes into the formation has obvious characteristics of "three zones", and the "pressed liquid stop zone" is the main factor controlling the damage degree of liquid resistance. Physical property, lithology and expansibility clay mineral content together constitute the 0-1 judgment value to determine the time-varying damage of fluid resistance in reservoir. The accuracy of the established multiple nonlinear regression prediction model of liquid resistance damage is greater than 80%, which can be used to quantitatively predict the liquid resistance damage degree of underground reservoir when it is difficult to conduct indoor simulation experiments in the evaluation of water intrusion damage degree.
The structure and composition of the upper mantle from joint inversion derived parameter relationships
Authors: Moorkamp Max
Published: February 2023

Geophysical methods such as seismology, magnetotellurics and gravity are key to reconstructing the structure of the upper mantle and inferring its composition. However, the relationship between composition and geophysical parameters, e.g. seismic velocity, resistivity or density, is complex and depends on other factors such as temperature, for example. This makes it difficult to untangle the various effects from inversions based on single parameters. Joint inversion establishes quantitative relationships between different geophysical parameters and thus provides additional information that can be interpreted in terms of composition and temperature. I use 3D joint inversion of surface wave, gravity and magnetotelluric data to construct integrated models in a data driven way. The relationship between the different quantities is recovered as part of the inversion through a Variation of Information based constraint. This constraint aims at establishing a one-to-one relationship between each parameter pair. Results from the western United States, Germany, Southern Africa and Australia show that this approach can retrieve highly detailed and strongly coupled results that can be interpreted, for example, in terms of hydration of the lithosphere. Comparison of results from different geologic domains indicates significantly different relationships depending on formation age. I will discuss how we can use data driven parameter relationships to infer the state of the lithosphere. In addition, I will outline the road towards robust quantitative inference based on these relationships.
Sulfur hexafluoride emissions – critical remarks on inversion techniques and inverse model results for the past two decades
Authors: Vojta Martin , Plach Andreas , Thompson Rona , Stohl Andreas
Published: February 2023

Inverse modeling provides a powerful tool to verify national greenhouse gas (GHG) emission inventories by using atmospheric observations. Often, inversions are based on Lagrangian Particle Dispersion Model simulations, where virtual particles are released from observation sites and traced backwards in time to establish a relationship between atmospheric concentrations and emission sources within the simulation period. The fact, that this simulation period is limited due to computational costs, raises two essential questions: (i) How to best define a baseline, that accounts for all emissions that occur prior to the simulation period? (ii) Which period length should be chosen for the backward-simulation?We show that often used statistical baseline methods have large problems and present a superior global-distribution-based (GDB) approach, that is consistent with the backward-simulation period, accounts for meteorological variability, and leads to inversion results that agree well with known global emission estimates. Our results further show, that longer backward-simulation periods beyond the often used 5 to 10 days increase the correlation between modeled and observed concentrations, and lead to more robust inversion results. Furthermore, they can help to better constrain emissions in regions poorly covered by the observation network.Based on these methodological results, we perform inversions for sulfur hexafluoride (SF6) - the most potent GHG regulated under the Kyoto Protocol with an estimated atmospheric lifetime of 3200 years. The inversions are based on 50-days backward-simulations, in-situ and flask measurements from various observation networks, and the GDB baseline method, to achieve globally and regionally consistent SF6 emissions from 2005 to present.
Emergent permeability in dehydrating rocks is controlled by the stress state and orientation
Authors: Fusseis Florian , Gilgannon James , Jacob Arne , Freitas Damien , Rizzo Roberto , Butler ian
Published: February 2023

Fluid-rock interaction relies on the fluid’s ability to migrate through rocks, utilising permeable pore space. While we understand permeability in rocks that interact with fluids to evolve dynamically, e.g. in dehydration or carbonation reactions, we have very little quantitative information on these dynamics, as direct measurements of permeability in reacting rocks are inherently difficult.Here, we present a series of permeability measurements that capture the evolving fluid transport properties of dehydrating gypsum samples. To derive these measurements, we used an X-ray transparent deformation rig to document gypsum dehydration in 4-dimensional µCT datasets and then modelled the permeability evolution for a segmented sub-volume numerically. In doing so, we were able to characterise the grain-scale porosity and permeability evolution of a dehydration reaction for the first time. We present analyses from two experimental time-series run at a fixed confining pressure, temperature and pore fluid pressure (Pc = 20 MPa; T = ~125 C; Pf = 5 MPa) but contrasting stress states: one with the largest principal stress (Δσ = 16.1 MPa) parallel to the sample cylinder axis and another the largest principal stress (Δσ = 11.3 MPa) being radial. In both cases, as pore space formed due to the negative change in the solid molar volume during the reaction, permeability evolved and increased congruently with porosity in time until ultimately reaching average values of 3.14E-13 m² and 4.55E-13 m², respectively. A clear spatial heterogeneity of fluid flow develops at the grain-scale along with the fabrics in the samples. Importantly,  the calculated permeability tensors are anisotropic from the onset, but  develop over different spatiotemporal trajectories and have different preferred orientations in the two experimental geometries: If the anisotropy is expressed as 1-(min_eigenvalue/max_eigenvalue) of the permeability tensor (where isotropy = 0), then the experiment with the largest principal stress applied radially has a final anisotropy of 0.45, with fluid flow efficiently focussed into a vertical lineation. In the case with an axial largest principal stress, the final anisotropy of permeability is 0.30 with fluid flow being channelled along a foliation that developed orthogonally to σ1.Our results suggest that the spatial and temporal developments of permeability during a dehydration reaction are controlled by the orientation and relative magnitudes of the principal stresses of a tectonic environment, and that these two parameters exert a strong control on the efficiency of drainage and thus reaction progress. This has consequences for our understanding of fluid movements in thrust tectonics and subduction zones, but also in applications such as the in-situ carbonation of ultramafic rocks.
Texture formation in Trapiche rubies
Authors: Cui Xinyu , Zhao Fufeng , Hou Zhaoliang
Published: February 2023

Abstract:Trapiche describes a gem texture that is characterized by the symmetric six “arms” radiating outward from the cores in gemstone minerals. These is a unique growth pattern, which however is still poorly understood. Here, we document the Trapiche in Trapiche rubies, and discuss formation mechanism of the patterns. The six arms of the Trapiche ruby radiate from a hexagonal core, which separate a single crystal into six growth sectors with internal bandings. Microscopic observations indicate a dendritic growth of the arms. Main branches are dominantly formed by the tube-shaped inclusions, and a part of which exhibit solid minerals, which including graphites, sulfides, calcites. The tube inclusions spatially have a 30° angle to the radiating direction of the arms, and pointing to the direction perpendicular to the hexagonal prism cylindrical {10Ī0}. Our Raman and EPMA analyses suggest that the origin of the ruby may be related to marble. Original source of the inclusions is aluminum-rich fluid with a high amount of CO2, which originated and evolved from magma. Our detail textural and chemistry on Trapiche ruby may suggest that during the ruby formation, a high crystallization driving force is necessary for arms to be a dendritic pattern which can overcome the growth interface of the bandings.    
Effect of hydrological and vegetation restorations on the C sink function of the disturbed La Guette peatland.
Authors: Bou Melhem Rima , Jourdain Line , Gogo Sébastien , Leroy Fabien , Jacotot Adrien , D'Angelo Benoît , Laggoun-Défarge Fatima , Guimbaud Christophe
Published: February 2023

Natural peatlands represent 1/3 of the world C soils and contribute significantly to sequestration of atmospheric CO2 by assimilation and storage of non-well decomposed organic C, due to their specific predominant vegetation such as Sphagnum species. However, they are encountering anthropogenic-induced pressures that disturb their structure (implying shift of vegetation), with potential consequences on their carbon sink function. In an attempt to mitigate this effect, restoration experiments were undertaken at La Guette peatland, a hydrologically disturbed temperate Sphagnum-peatland invaded by vascular plants, which is now a carbon source. Hydrological restoration was performed by blocking drains with dams and vegetation restoration was undertaken by either i) removing first 5 cm of peat (bare plots) or ii) removing first 5 cm of peat and transferring Sphagnum mosses (Sphagnum plots). To study the effect of these experiments, CO2 and CH4 fluxes together with environmental variables and vegetation indices were monitored from 2014 to 2017 in 24 2mx2m plots. The annual carbon budget for each plot was estimated using empirical models. Preliminary results show that the hydrological restored site presented lower annual mean CO2 emissions than the undisturbed site. In addition, Sphagnum plots had the lowest annual mean CO2 emissions followed by bare peat plots then by intact plots. Hence, the results of these models provide evidence that hydrological and vegetation restorations favour the return to the C sink function of the peatland. However, there is still a need for larger-scale studies to better estimate the effect of restoration activities on peatland greenhouse carbon budgets.
Using the expertise within our communities to advance the IMPACT of scientific ocean drilling
Authors: Cotterill Carol , Cooper Sharon , White Lisa , Haas Don
Published: February 2023

The IMPACT workshop series was developed in direct support of the 2050 Framework for Scientific Ocean Drilling and its call to "communicate far-reaching scientific ocean drilling knowledge to the broader community." IMPACT's goal is to build relationships and collect information from an array of different voices. Collectively, the Scientific Ocean Drilling IMPACT workshop series strives to chart the future course of science communication and outreach for scientific ocean drilling.The summer 2021 virtual workshops explored STEM education and science communication, engaging workshop participants as collaborators, while paying special attention to issues related to diversity and inclusion. The 2022 IMPACT in-person workshop built on and drew from the summer 2021 virtual workshops to move the community forward in its approach to broader impacts for scientific ocean drilling. The findings from the workshop series are helping to create a blueprint for a science communication strategy that is an integral part of implementation of the 2050 Framework for Scientific Ocean Drilling.In this paper we present a set of strategies with actionable plans for the next 5 years and beyond, through the evolution of 5 “Big Idea” topics and 19 projects that resulted from group brainstorming. Each idea is being led by a community-based group, who have worked to identify possible funding streams, partners and desired outcomes. This grassroots approach gives strength to the proposed ideas, coming from the community and charting the course for the community going forward.
SWE retrieval in the European Alps based on Sentinel-1 snow depth observations and modeled snow density
Authors: Boeykens Lucas , Lievens Hans , Beernaert Ezra , Jans Jonas-Frederik , Verhoest Niko
Published: February 2023

Seasonal snow is an essential source of water, especially in mountainous regions. However, accurate satellite observations of the snow water equivalent (SWE), i.e., snow depth multiplied by the snow density, are still lacking. Therefore, new and robust remote sensing techniques are urgently needed. This study presents a novel method for SWE retrieval in mountainous regions at sub-weekly temporal and 500-m spatial resolution, based on snow depth observations from the ESA and Copernicus Sentinel-1 (S1) satellite mission and model simulations of snow density. The snow depth observations rely on a change detection algorithm which translates the temporal changes in the S1 radar backscatter measurements into the accumulation or ablation of snow. The snow density estimates are obtained from different modeling approaches, including empirical methods (e.g., based on the day of the year, the snow depth, snow climate class, etc.) and a physics-based mass and energy balance model. The performance of the different snow density modeling approaches is here compared, both with respect to their ability to accurately simulate in situ measurements of snow density, as well as their ability to accurately simulate in situ measurements of SWE after combination with the S1 snow depth observations. The performance is evaluated over the European Alps, using a large dataset of in situ time series measurements for the period 2015-2022. The results show that the physics-based snow density modeling approach outperforms the empirical approaches, yielding high spatio-temporal correlation between S1 SWE retrievals and in situ measurements. Therefore, the study demonstrates the capability of the Sentinel-1 satellite mission, in combination with a physics-based snow model, to accurately represent the spatio-temporal distribution of SWE in mountainous regions, which can benefit a large range of applications, including hydropower generation, water management, flood forecasting, and numerical weather prediction.
Direct flow visualization and transport processes in transparent 3D porous media
Authors: Souzy Mathieu
Published: February 2023

Geomaterial are complex porous material presenting a wide diversity of structures, which set how a fluid will flow through it. The understanding of the mechanisms controlling the flow kinematics at the pore scale is however decisive to predict and control transport processes (dispersion and mixing) and to relate them to the macroscale behaviour of porous materials. Because of the opaque nature of porous media, the flow visualization and characterization of the velocity fields within a porous media is particularly challenging in three-dimensional (3-D) porous media. However, recent development of experimental techniques including index matching, allow to develop transparent porous media to perform direct visualization of the flow in these artificial material.I will here discuss about how such approach have already been successfully implemented to study porous media composed of randomly packed solid monodisperse spheres, allowing to directly visualize the flow within the bulk of the 3-D media, and to investigate how a blob of dye stretches and get mixed when injected within such 3-D porous media. Using Particle Image Velocimetry techniques (PIV), these promising techniques also allow to perform successive scans of the velocity field, providing highly resolved experimental reconstruction of the 3-D Eulerian fluid velocity field in the bulk of the porous media. This approach is therefore promising to further investigate flow kinematic in more complex porous media, or to directly visualize other crucial mechanisms in such media, like for instance erosion, clogging, or the effect of strong heterogeneities on the overall flow behavior.
T-waves triggered by Chilean earthquakes recorded at CTBT-IMS station HA03
Authors: Oliveira Tiago , Zampolli Mario , Metz Dirk , Haralabus Georgios , Barrientos Sergio
Published: February 2023

In addition to monitoring the oceans for signs of nuclear explosions, the International Monitoring System (IMS) hydroacoustic data have been used for a broad range of civil and scientific applications, including the study of submarine earthquakes. This presentation analyzes T-wave signals recorded at CTBT-IMS hydrophone station HA03 triggered by Chilean earthquakes between 2014 and 2022. HA03 is located in the Juan Fernández Islands (Chile, South-East Pacific Ocean); in particular, the hydrophone arrays are located approximately 15 km north (H03N) and 15 km south (H03S) of Robinson Crusoe Island to account for the acoustic shadow produced by the islands. Arrival time and back azimuth of the recorded T-waves were estimated using the Dase ToolKit - Graphical Progressive Multi-Channel Correlation (DTK-GPMCC) program. Different arrivals within the duration of the earthquake signals were identified. However, discrepancies between expected and measured back azimuths can be observed for H03N and H03S. A three-dimensional underwater acoustic model was utilized to determine the cause of these differences. Based on the hydroacoustic arrivals identified for the analyzed earthquakes, a discussion is provided on the conversion from seismic to acoustic waves (T-waves generation zone). Moreover, reflected propagation paths induced by bathymetric features along the path from the T-waves generation zone to H03N and H03S are discussed.
Tsunami study from underwater landslides in the Gulf of Naples - Southern Tyrrhenian Sea, Italy: importance of the landslides directionality in 3D numerical modeling
Authors: Punzo Michele , Albarello Dario , Cavuoto Giuseppe , Pelosi Nicola , Tarallo Daniela , Di Fiore Vincenzo
Published: February 2023

In this study, we propose a 3D numerical modeling of tsunami waves generated by an underwater landslide. The simulated gravity instabilities are located in the Gulf of Naples. The availability of a detailed bathymetric map both with a good knowledge of the local geology allowed us to obtain reliable simulation results. Submarine landslides in the Gulf of Naples can be considered a potential tsunami hazard for the following reason: some dated landslides in the Gulf of Naples, suggest that triggering conditions for these landslides are connected to the seismicity of the area. There are many geological evidences of tsunami events in Gulf of Naples. In fact, several papers describe the effects induced by geological events on the tsunami origin. GEOWAVE numerical model was employed to simulate tsunami generation and propagation. Model results revealed that this probable landslide tsunami is capable of generating high waves and considerable run-ups along the coasts of countries near the landslide zone. A further important role in this study is determined by the directionality of the landslide which strongly influences the tsunami energy.
Effect of slope position on hydrochory processes: a natural rainfall study in tropical agroecosystem
Authors: Grellier Seraphine , Pansak Wanwisa , Intanon Suphannika , Rodprai Chanisara , Anusorn Khwanrawee , Hammecker Claude , Janeau Jean-Louis
Published: February 2023

Soil erosion due to land use change and consequently biodiversity loss are major concerns in agricultural areas. However, the link between runoff, soil loss and plant dispersion by water also called hydrochory is not yet well understood, especially in tropical climate. The displacement of native plant seeds on the soil surface by runoff may be influenced by soil properties and by agricultural practices. This may in return affect or modify biodiversity in agroecosystems.This is why we propose to study the processes affecting seed displacement by runoff in steeply sloping maize field affected by rainfall and tillage erosion in Northern Thailand.After a first study under rainfall simulation in situ (Janeau et al. 2022), we present here a two years study under natural rainfall to assess the role of position in the catena and soil properties on seed displacement, soil loss and nutrient losses. We used 24 plots of 1 m2 located at four positions in the catena. Two treatments were tested: (1) conventional system with tillage and (2) biochar incorporated into the soil. We measured the displacement of seeds (only for treatment 1), runoff volume, soil and nutrient losses and soil surface features (for the two treatments) during two years of study.Preliminary results indicate a strong influence of catena position on all studied variables. This may be due to soil properties changing along the catena, as well as shape (concave or convex) of the slope position. As expected, rainfall intensity seemed influencing runoff and soil and nutrient losses, together with seed displacement.This study, under tropical climate and steep slope conditions, highlights differences in soil surface features and runoff along the catena. We should consider catena position for improving soil management and using appropriate agroecological practices.
Influence of soil overburden thickness on water infiltration and evaporation characteristic in post-mine restoration
Authors: chengzhi li
Published: February 2023

Exploitation of coal mining is an important part for economic development, but the exploitation of coal mining will bring a serious impact on the local ecological environment. Ecological restoration is an effective method to improve the ecological environment in the mining areas. The first step of ecological restoration in post-mine is  to rebuild a sustainable mine-soil system. Fine soil overburden is often used in reconstructing soil profiles to provide habitat for vegetation restoration. Fine soil overburden will change the infiltration and evaporation of soil water. However, the understanding of the infiltration and evaporation of soil water is still an ongoing challenge. In this study, four groups of clay soil thicknesses (25 cm, 20 cm, 15 cm and 10 cm) were set up to simulate the overburden fine soil in post-mine ecological restoration, to study the influence of cover fine soil thickness on soil water infiltration and evaporation. The results showed that: a) the correlation between cover clay soil thickness and wetting front migration velocity was negative, namely, the thicker the cover clay soil thickness, the slower the wetting front migration velocity, and the smaller the average infiltration velocity is. However, the amount of water holding in thick overburden clay soil was more than the thin overburden clay soil. b) The overlying clay soil would improve soil water evaporation, but it wasn’t significant(p>0.1) with the thickness. The amount of soil water evaporation was low than the amount of water infiltration in thick overburden clay soil, so, the thick overburden soil could hold more water for the vegetation utilization. c) With the progress of soil water evaporation, the rate of evaporation was decreased with the increase of clay soil cover thickness. The greater the soil cover thickness, the stronger the soil water retention capacity. From the experimental result, the thick clay soil cover could remain more water, and is more suitable for vegetation establishment in post-mining restoration.
Nitrous Oxide, N2O: Spectroscopic Investigations for Future Lidar Applications
Authors: Kiemle Christoph , Fruck Christian , Fix Andreas
Published: February 2023

Nitrous Oxide, N2O, is the third most important GHG contributing to human-induced global warming, after carbon dioxide and methane. Its growth rate is constantly increasing and its global warming potential is estimated to be 273 times higher than that of CO2 over 100 years. The major anthropogenic source is nitrogen fertilization in croplands. Soil N2O emissions are increasing due to interactions between nitrogen inputs and global warming, constituting an emerging positive N2O-climate feedback. The recent increase in global N2O emissions exceeds even the most pessimistic emission trend scenarios developed by the IPCC, underscoring the urgency of mitigating N2O emissions (Global Carbon Project, 2020). Estimating N2O emissions from agriculture is inherently complex and comes with a high degree of uncertainty, due to variability in weather and soil characteristics, in agricultural management options and in the interaction of field management with environmental variables. Further sources of N2O are processes in the chemical industry and combustion processes. The sink of N2O in the stratosphere increases the NOx concentration which catalytically depletes ozone. Better N2O measurements thus are urgently needed, particularly by means of remote sensing.Airborne or satellite based N2O lidar remote sensing combines the advantages of high measurement accuracy, large-area coverage and nighttime measurement capability. Past initial feasibility studies revealed that Integrated-Path Differential-Absorption (IPDA) lidar providing vertical column concentrations of N2O would be the method of choice. In this current study we use the latest HITRAN spectroscopic data in order to identify appropriate N2O absorption lines in the wavelength region between 2.9 and 4.6 µm. The infrared spectral region challenges both lidar transmission and detection options. On the transmitter side, the use of optical parametric conversion schemes looks promising, while HgCdTe avalanche photodiode (APD), superconducting nanowire single-photon (SNSPD) or upconversion detectors (UCD) could offer high-efficiency low-noise signal detection. These options are implemented into a lidar simulation model in order to identify the optimal lidar system configuration for measuring N2O from aircraft or satellite using state-of-the-art technology.
Spatial distribution of intermittency in a Brazilian Semiarid river
Authors: Soares Nazaré Suziane , Costa Carlos Alexandre Gomes , Francke Till , Medeiros Pedro Henrique Augusto , Mohr Christian , Schwanghart Wolfgang , De Araújo José Carlos
Published: February 2023

Intermittent and ephemeral rivers are characterized by periods of drying and rewetting which occur along different reaches of the channel. Where the channel dries or develops into ponds related to factors such as discharge, topography, geology and riparian vegetation. The aim of this work is to evaluate the spatial patterns and dynamics of intermittency in reaches of a Brazilian semiarid river. Using repeated surveys with unmanned aerial vehicles (UAVs), we characterize its connectivity by identifying locations with different water condition. The Umbuzeiro River (approximately 80 km long; 6.65°S, 40.41°W) is the main river in the Benguê catchment (~1000 km²) that is controlled by the Benguê reservoir, with a storage capacity of 18 hm³. Umbuzeiro is an intermittent/ephemeral river and spatially coherent streamflow occurs mainly in the wettest months of the rain season. We conducted UAV surveys each month from March to June 2022, allowing us to produce detailed hydrological characterizations along different sections of the river. The imagery sets from different UAVs, i.e. DJI Phantom 4 pro and eBee SQ, provided relatable characteristics for a same reach. Visually analysing the reaches, their water condition was determined for smaller subsets, i.e. ponds or dry spots. Observing the temporal and spatial patterns of the presence of water on the riverbed in the different reaches for each survey, we conclude that the patterns are not only dependent on the contributing area of each section, but also on the river’s natural sinuosity, riffle-pool sequences and riparian vegetation. Our results highlight and provide an explanation for the hydrological diversity of semiarid rivers which is important to understand their ecological role and habitat.
Ecosystem-based approaches for flood risk reduction: Advances in their comprehensive evaluation using the case of the Ouémé River Basin in Benin
Authors: Balzer Jana , Janzen Sally , Merk Fabian , Walz Yvonne
Published: February 2023

Floods are amongst the most frequent and widespread disaster worldwide, posing enormous development challenges. Also in West Africa, flood risk still needs proper addressing. Ecosystem-based disaster risk reduction (Eco-DRR) approaches are increasingly recognised as cost-effective part of the solution, providing ecosystem services that reduce all three components of risk, namely hazard, exposure and vulnerability. Indeed, Eco-DRR, such as floodplain restoration or agroforestry, can affect hydrological processes, altering the flood hazard and exposure, and provide ecosystem services that reduce people’s vulnerability to floods and/or enhance their adaptive capacities. To fully understand the impact of Eco-DRR on the three components of risk, it is thus important to take an interdisciplinary approach to the assessment of Eco-DRR. Yet, there remains a substantial gap in the comprehensive evaluation of Eco-DRR effects, including guidance on how to depict the flow of ecosystem services and their benefits to people, which undermines the effective use of Eco-DRR measures in flood-prone environments.Using the case study of flood risk in the Ouémé River Basin, this contribution will share advances in the comprehensive evaluation of Eco-DRR measures. After defining locally-relevant Eco-DRR measures based on administrative plans, the scientific literature, and expert surveys, a systematic literature review has been conducted to understand the impact of selected Eco-DRR measures on both hydrological processes and ecosystem services provisioning, so as to evaluate the Eco-DRR measure against its effects on all risk dimensions. For the hazard, the hydrological model SWAT is used, comparing the flood hazard under different land use and land cover change scenarios. Preliminary results, with a focus on the Eco-DRR measure of agroforestry, and lessons learnt will be presented in the session.
Modelling the sedimentary source and diagenetic fractionation of Rare Earth Elements in the ocean
Authors: Du Jianghui , Vance Derek
Published: February 2023

Rare Earth Elements (REE) are among the key tracers in modern chemical oceanography. Yet their budgetary imbalance in the modern ocean has limited our understanding of their marine biogeochemical cycling and their applications as paleo-proxies. The flux of REE across the sediment-water interface appears to be the dominant source of REE to the ocean. Most studies on the marine and sedimentary cycling of REE focus particularly on neodymium (Nd), which has a radiogenic isotope system that helps to constrain its ocean budget. Recently we developed a reactive transport model to study the diagenesis of Nd at a deep sea site on the Oregon margin, which successfully explained the distributions of Nd and its radiogenic isotope in pore water and authigenic sediment, and the diagenetic control of the benthic Nd flux to the ocean. Here we extend this model to include the whole REE series. We show that the transformation and fractionation of REE in sediment can be adequately modelled only via reactions between pore water, authigenic Fe/Mn oxides and phosphates. Using the model result we can scale the sedimentary sources of the rest of the REE elements to that of Nd, providing better constraints on the ocean budgets of all REE.
Short and long-term size changes of calcareous nannofossil Watznaueria barnesiae across the latest Barremian- late Cenomanian interval (Cretaceous) in the western Tethys.
Authors: Bettoni Chiara , Bottini Cinzia , Castiglione Silvia , Erba Elisabetta , Raia Pasquale
Published: February 2023

Calcareous nannofossil Watznaueria barnesiae is a resistant and tolerant species and previous morphometric studies have evidenced minor (Erba et al., 2010; Lubke et al.2016) or no size changes during Oceanic Anoxic Events (OAEs) (Bornemann et al. 2006; and Faucher et al. 2017b) as well as during the Cenomanian to Maastrichtian (Linnert et al. 2014). Here, we present the morphometric record from the western Tethys (Cismon core from the Belluno Basin; Piobbico core and the Monte Petrano section from Umbria-Marche Basin, Italy) across the latest Barremian- late Cenomanian which represents a relatively long-time interval (ca. 26 Myrs) marked by interludes of profound changes in the ocean and climatic conditions named (OAE 1a, 1b and 1d). Our study shows that indeed W. barnesiae experienced coccolith and central unit variations during the studied interval. Specifically, smaller coccoliths with also smaller central unit marked the early Aptian to early Albian. The middle Albian to the early Cenomanian was characterized by larger and rounded coccoliths without significant changes in the central unit dimension. Short-term size changes are detected in correspondence of OAE 1a and OAE 1b marked by W. barnesiae size decrease. Particularly, OAE 1a was characterized by the smallest and most elliptical specimens of the studied interval. During the OAE 1b W. barnesiae coccoliths were characterized by a moderate decrease in the mean size, because specimens were already smaller before the event. The morphometric data were correlated with calcareous nannofossil temperature and nutrient indices calculated on the same samples investigated for morphometry. Long-term size changes do not show a clear correspondence with temperature and nutrient variations. W. barnesiae size changes across the early Aptian to early Albian may be related to large igneous province activity. Short-term size variations during OAE 1a and OAE 1b were influenced by the combination of large CO2 emissions, temperature and fertility increase. In conclusion, although W. barnesiae is a resistant and tolerant species it shows morphometric changes both in short- and long-term, probably in response to partially different causes.  
Decadal grounding line migration and ice shelf melt regime of Petermann Glacier, North-West Greenland, from high-resolution InSAR data.
Authors: Ciracì Enrico , Rignot Eric , Scheuchl Bernd , Tolpekin Valentyn , Wollersheim Michael , An Lu , Milillo Pietro , Bueso-Bello Jose Luis , Rizzoli Paola , Dini Luigi
Published: February 2023

Petermann Glacier (80.75N, 60.75W) terminates in one of the most extensive remaining ice tongues of the Greenland Ice Sheet. The glacier is grounded 600 meters below sea level on a downsloping bed and could significantly contribute to sea level rise during the 21st century. Recent observations showed an ongoing acceleration in ice flow and kilometric-scale grounding line retreat after decades of stable dynamic conditions. Warming of the ocean waters surrounding Greenland has been indicated as the main driver of this process. However, the melting regime of the glacier at the interface between ocean waters and grounded ice is not well known and needs to be investigated.In this study, we achieve this goal by employing a time series of satellite radar interferometry data available between 2011 and 2022. We document grounding line migration using high-frequency observations from the Italian COSMO-Skymed constellation and the Finnish ICEYE constellation. Furthermore, we use time-tagged digital elevation models from the German TanDEM-X mission to assess the ice shelf basal melt regime in a Lagrangian framework.InSAR observations reveal kilometer-size grounding line migrations - (2-6 km) grounding zones - during tidal cycles, with preferential seawater intrusions of 6 km along pre-existing subglacial channels. In addition, results from the Lagrangian approach indicate that the highest ice shelf melt rates occur at these locations, with values reaching peaks ranging from 60 to 80 meters per year.Such high melt rates concentrated in kilometer-wide grounding zones contrast with the traditional plume model adopted by physical models with zero melt at a fixed grounding line. Their inclusion in physical models will increase the glacier's sensitivity to ocean warming and double the projections of sea level rise from the glacier.This work was supported by a grant from NASA.
Anthropogenic processes alter the completeness and resolution of the marine fossil record
Authors: Nawrot Rafał , Zuschin Martin , Tomašových Adam , Kowalewski Michał , Scarponi Daniele
Published: February 2023

The youngest fossil record is an indispensable source of data on long-term human impact on marine ecosystems. However, human actions alter not only marine communities and their habitats but also sedimentary and biotic processes controlling the formation of the stratigraphic archives recording those changes. Based on literature data and our own field studies we provide a conceptual framework for understanding the impact of anthropogenic processes on the completeness and spatiotemporal resolution of the fossil record forming on continental shelves. Such processes are diverse and include, among others, changes in sediment fluxes due to reshaping of alluvial and coastal landscapes, seabed disturbance by bottom trawling and ship traffic, ocean acidification and anoxia, removal of native species, and introduction of invasive ecosystem engineers. These physical, geochemical, and biological disturbances can modify sedimentation rates, depth and intensity of sediment mixing, pore water saturation state, and preservation potential of skeletal remains. The resulting taphonomic and stratigraphic signatures can pinpoint historical changes in ecosystem functioning but can also lead to systematic changes in the quality of the record complicating paleoecological and paleoclimatic reconstructions based on the data from sediment cores and surface death assemblages. We highlight the complex feedbacks between human impacts on the ecosystem processes and their preservation in the marine stratigraphic record and suggest research strategies that can maximize the informative value of the geohistorical data.
Tropical cyclone precipitation skill in S2S models
Authors: Garcia-Franco Jorge L , Lee Chia-Ying , Camargo Suzana , Tippett Michael , Kim Daehyun , Molod Andrea , Lim Young-Kwon
Published: February 2023

Tropical cyclone precipitation (TCP) contributes a significant fraction of total annual rainfall and also is a frequent cause of extreme precipitation in many parts of the tropics. The climatology of TCP in the S2S models is characterized by dry biases in the North Atlantic and wet biases in most other basins,  specially in the Southern Indian Ocean and Australia. Biases in total precipitation (P), TCP and their ratio (TCP/P) are mostly positive in the multi-model ensemble mean and change very little with lead time. in these models the frequency biases are the dominant contribution to TCP biases. However, in some models, there are positive biases in average precipitation per each TC which contribute significantly to TCP biases at equatorial latitudes.The prediction skill of these reforecasts is evaluated using skill scores such as the ranked probability skill score for TCP and the Brier Skill score for genesis and occurrence. The implication of these results is discussed for their relevance to mean and extreme precipitation prediction skill using S2S models.