bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of fractures on the Biot and Skempton coefficients of fractured rocks  
Authors: De Simone Silvia , Darcel Caroline , Kasani Hossein , Mas Ivars Diego , Davy Philippe
Published: March 2024

The Hydro-Mechanical (HM) behavior of fluid-saturated porous materials is crucial in determining the response of the subsurface to natural processes, such as glaciation, and to engineering applications, such as construction/excavation, reservoir impoundments, geo-energy extraction, and deep geological disposal of used nuclear fuel. Two fundamental coefficients, i.e., the Biot coefficient and the Skempton coefficient, define the contribution of the fluid in subsurface media to maintain the mechanical equilibrium against perturbations in stress and pore fluid pressure. Despite the central importance of these two coefficients, which may broadly range between 0 and 1, their estimation is often oversimplified in most scientific and engineering studies that treat large-scale saturated problems by assuming a uniform geological material, with the coefficients estimated experimentally at the laboratory sample-scale or analytically through expressions valid for isotropic homogeneous materials.In this work, we analyze the impact of fractures on the HM behavior of fractured rocks by looking at the equivalent Biot coefficient and Skempton coefficient. We adopt a recently defined framework in which the equivalent coefficients are estimated from the properties of both the porous intact rock and the discrete fracture network (DFN), including fracture size, orientation and mechanical properties. We extend this theory to incorporate more realistic assumptions on fractures, such as size-dependent and stress-dependent fracture properties. This setting allows us to explore the range of variability of the two equivalent coefficients with respect to the stochastic distribution of fracture size and orientation in the rock, and with respect to depth and stress faulting regime. We show that the coefficients are larger if 1) the network is placed in shallow rocks (i.e., low stress regime), 2) the network is populated by a few large fractures rather than by many small fractures, and 3) the fractures are oriented parallel to the in-situ maximum principal stress and normal to the applied stress.
Reducing snow amount Uncertainty in CMIP6 Pan-Canadian Climate Projections
Authors: Matte Dominic , Leduc Martin , Labonté Marie-Pier , Paquin Dominique
Published: March 2024

Recent studies have demonstrated that the uncertainty in projections can be reduced by weighting the GCMs based on their ability to accurately reproduce historical climate conditions in specific geographical regions. This study aims to reduce the uncertainty in projections of the annual maximum snow amount from obtained from the most recent iteration of GCMs in the Coupled Model Intercomparison Project Phase 6 (CMIP6). To do so, we implement a three-phase approach in order to adapt the Climate model Weighting by Independence and Performance (ClimWIP) algorithm to the main drivers of snow-amount projections.Phase one of our research involves identifying and implementing the most effective metric combinations that yield a weighted field closely aligning with the reference dataset's state. In phase two, these optimal combinations are applied within a perfect model protocol to determine the most appropriate combination for practical application. The final phase uses the selected combination to compute weights specifically for the climate projection of the annual maximum snow amount.Our findings indicate that our approach primarily impacts regions where snow amount is a critical factor. Additionally, we observe a narrowed range of uncertainties in both the annual maximum snow amount and the 2-meter temperature projections. This study's outcomes not only demonstrate the efficacy of our approach but also offers valuable insights for future climate projection and adaptation strategies in Canada.
Long-term Dynamics of Carbon Sequestration in Tropical Meandering Rivers through Remote Sensing, Numerical Modeling, and Stochastic Processes
Authors: Camporeale Carlo , Bassani Francesca , Salerno Luca
Published: March 2024

This research explores the long-term impacts of intricate dynamics of fluvial corridors on the carbon cycle, focusing on the interaction with tropical meandering rivers during formative events and riparian vegetation, particularly large wood recruitment. A multidisciplinary approach – including satellite data analysis, deterministic modeling and stochastic processes – is employed to assess the magnitude of carbon exported by these rivers.Meandering rivers exhibit lateral migration, with continuous erosion and deposition shaping their dynamics. Riparian vegetation, impacted by flooding and cutoff events, plays a pivotal role in carbon recruitment. A satellite-guided methodology across the Amazon basin  correlates river-induced forest cover loss with eroded areas to estimate carbon recruitment.To understand the long-term river dynamics, a stochastic toy model linking river evolution, sinuosity and carbon export is proposed.  The model equation for sinuosity growth includes deterministic and noisy terms, accounting for river elongation and cutoff events, respectively. In particular, a compound Poisson process is used to describe the evolution of sinuosity over time, revealing the impact of cutoff events on long-term dynamics. The calibration of the parameters characterizing the Poisson process is performed through the results of numerical simulations for river planar evolution, based on Zolezzi and Seminara (2001) morphodynamic  model.This study indicates a close relationship between the carbon sequestration and the dynamics of tropical rivers, emphasizing the negative impact of alterations like damming and mining on river morphodynamics and carbon storage. This research provides valuable insights into the complex interactions within fluvial corridors, contributing to our understanding of carbon cycling in these critical ecosystems.
Solid Earth’s response to climate change in Svalbard monitored by space geodesy 
Authors: Tafflet Alicia , Nicolas Joelle , Boy Jean-Paul , Lemoine Jean-Michel , Perosanz Félix , Durand Frédéric , Koulali Achraf , Gourillon Lissa , Baltzer Agnès , Verdun Jérôme
Published: March 2024

The Svalbard archipelago in the Arctic is extremely sensitive to climate change. The resulting redistribution of mass, including recent and past ice melt, induces deformations of the Earth's surface and temporal variations in its gravity field, which can be detected by space geodesy. The cross-comparison of different techniques takes advantage of their complementary temporal and spatial resolutions, helping to distinguish between local, regional and global signals. We analyse more than 20 years of GNSS (Global Navigation Satellite System) satellite 3D positionning solutions at 17 permanent sites. The results are compared with deformations computed from time gravity field variations observed by the space gravimetry missions GRACE (Gravity Recovery and Climate Experiment) and GRACE Follow-On. The mean vertical motion is of about 9 mm/year and can reach 15 mm/year. We then compare these GNSS and GRACE datasets with Little Ice Age (LIA) and Global Isostatic Adjustment (GIA) models as well as with satellite altimetry observations from Cryosat-2 and IceSat-2. We infer the various contributions and quantify the impact of the current climate change on Svalbard. In addition to better estimate the acceleration of the current ice melting we apply an innovative seasonal adjustment method. The results are then discussed in relation to in situ observations.
Forging collaborative approaches for enhancing Earth Observation product uptake in the Cloud Era.
Authors: Mantas Vasco , Portier Andrea
Published: March 2024

Facilitating the seamless progression of data discovery, access, processing, analysis, and distribution of insights stands as a cornerstone within Earth Observation (EO) missions, further amplified by the widespread migration of major data archives towards cloud infrastructures across the globe. However, impediments in the data flow from providers to end-users can and do persist, particularly under the cloud paradigm, fostering the exclusion of certain communities and curtailing their ability to harness actionable insights for research, practical applications, and informed decision-making.
Integral to the Earth Observation value chain is the strategic design of robust capacity-building frameworks and networking structures. This facet assumes paramount importance as it transcends the mere adoption of FAIR (Findable, Accessible, Interoperable, Reusable) principles, ultimately enhancing product adoption and utilization.
The Global Precipitation Measurement Mission (GPM) Mentorship Program serves as an example of a successful initiative, catering to a diverse global audience by forging connections between domain experts and users. The program's structure, from the development of lecture series to the practical implementation of capstone projects across various domains (e.g., extreme precipitation events, ground validation, water resource management), yields a wealth of insightful and reusable lessons. Notably, participants hailing from over 40 countries have shed light on the multifaceted barriers slowing down or impeding product adoption, typifying the diverse landscape of agencies, academic institutions, and non-governmental organizations engaged in the initiative.
The GPM Mentorship Program has evolved into the focal point of an interconnected ecosystem of collaborative initiatives, all unified by a shared objective while being custom-tailored to address the distinct requirements and diverse user communities within the Earth Sciences domain. Ultimately, co-designing adaptable and inclusive capacity-building frameworks emerges as a pivotal requirement in facilitating EO data uptake and a seamless transition to the cloud paradigm. This approach not only bolsters and sustains diversity within the Earth Sciences but also fosters evidence-based decision-making both at global and local levels, thus underlining its pivotal role in shaping a more informed and resilient future.
Soil organic matter quality along an urbanization gradient in Paris region
Authors: Lerch Thomas Z. , Foti Ludovic , Nunan Naoise , Abbadie Luc , Barot Sebastien , Raynaud Xavier , Lata Jean-Christophe
Published: March 2024

Studying carbon stocks and fluxes in urban soils is becoming increasingly relevant, considering the continuous urbanization. Although they represent a relatively small area compared to forest or arable soils, urban soils could be considered as hot spots of anthropogenic carbon accumulation as it is estimated that they contain 3-5 times as much C per ha as natural soils (Vasenev & Kuzyakov, 2018). To date, few studies have investigated urban soil organic matter (SOM) quality and stability, i.e. its resistance to microbial decomposition. In this study, we evaluated the ability of thermogravimetry to predict SOM mineralization kinetic parameters at a regional scale. In order to achieve this, 180 soil samples were collected from two different land uses (lawns and woodlands) along a gradient of urban pressure (rural, suburban and urban areas) in the Paris region (France). We determined SOM mineralization kinetic parameters by measuring CO2 emissions in long-term incubations and the thermal stability of SOM by thermogravimetry combined with differential scanning calorimetry and evolved gas analyzes (TG-DSC-EGA).  The SOM quality was also characterized by using Mid Infra-Red Spectrometry (MIRS). Overall, SOM thermal stability increased from the rural to the urban areas in both land-use types. Urban woodland soils had greater SOM thermal stability than urban lawns, probably because the woodlands are much older than the lawns and because of historical soil management legacy in Paris region. Significant and strong relationships were found between SOM thermal analysis indices (CO2-T50 and energy density) and mineralization kinetics parameters (mineralizable C and turnover) measured in the laboratory. MIRS analyses revealed different chemical compositions depending on land use (higher aromaticity and condensation indices in lawns) and the urban gradient (lower polysaccharides content and aromaticity index in cities). This regional scale study suggests that 1) the thermal analysis of SOM, together with MIRS and soil physico-chemical measurements can be used to predict soil C mineralization potential and 2) SOM thermal stability and resistance to microbial mineralization are higher in urban soils, especially in woodlands.
Inter-decadal variations in water balance-derived catchment evapotranspiration in Central Europe and their uncertainties
Authors: Bruno Giulia , Duethmann Doris
Published: March 2024

Long-term variations in catchment evapotranspiration control water availability for human societies and freshwater ecosystems, with potential negative impacts particularly during low-flow conditions. Previous studies reported increases in water balance-derived evapotranspiration for parts of Central Europe, mostly between 1980s and 2010s. However, knowledge gaps still remain around (i) the extent of these increases in space and time, and (ii) uncertainties from the catchment water balance. Here we analyse trends in water balance-derived evapotranspiration for 461 German near-natural catchments, over multiple time windows in the last six decades. We constrain uncertainties through estimates of storage changes derived from recession analysis and the use of multiple precipitation products. Results show wide-spread, significant increases in catchment evapotranspiration during 1970s–2000s (for example, average regional trends of 3.2 mm year-2 with an uncertainty from precipitation of ±1 mm year-2 for the period 1970–2002). Yet, catchment evapotranspiration shows no significant changes or rather a tendency to the decrease after 2000s (-3.6±1.4 mm year-2 for Pre-Alpine catchments over 2000–2019). The directions of these variations are robust to the considered uncertainties and consistent with sparse in-situ data. We further discuss implications of these variations with respect to low-flow conditions.  This study offers a comprehensive synthesis on past variations in catchment evapotranspiration and their uncertainties, which is critical for a proper understanding of recent hydrological changes.   
Mitigation of GHG emission from the wastewater treatment plant: Life cycle assessment approach
Authors: Vidyarthi Praveen Kumar , Arora Pratham , Blond Nadège , Ponche Jean-Luc
Published: March 2024

The rapid expansion of wastewater treatment plants, aimed at mitigating global water stress, has significantly increased the energy demand. In India, the anticipated rise in sewage generation to treatment ratio from 46% to 80% by 2050 [1]. It is expected to further intensify the energy demand of treatment facilities to meet national standards. This required energy, predominantly in the form of electricity, primarily fulfill from coal-based thermal plants, consequently contributing to air pollution and emissions. Moreover, enhancing the oxygen supply in the biological process to improve treatment efficiency is projected to escalate direct greenhouse gas (GHG) emissions. India's central electricity authority reports that the Indian grid produces around 0.91 kg CO2eq/kWh. A typical wastewater treatment plant (WWTP) demands an average of 185 kWh per million litres per day (MLD), resulting in approximately 168.35 kilograms of CO2 equivalent emissions per MLD [2]. Exploring alternative mitigation measures becomes imperative to address the energy demand from the grid. One approach involves employing mitigation technologies like gasification, anaerobic digestion, or pyrolysis to generate electricity from the sludge process. The study aims to estimate direct and indirect emissions from WWTPs by conducting a comprehensive life cycle assessment of various mitigation technologies. Notably, gasification, anaerobic digestion, and pyrolysis demonstrate potential emission reductions of around 81.8%, 57.2%, and 36.4%, respectively.
Joint verification and evaluation of seasonal forecasts from climate services: Experience from the H2020 CLARA project
Authors: Crochemore Louise , Materia Stefano , Delpiazzo Elisa ,   H2020 CLARA project team
Published: March 2024

Assessing the information provided by co-produced climate services is a timely challenge given the continuously evolving scientific knowledge and its increasing translation to address societal needs. Here we propose a joint evaluation and verification framework to assess prototype services that provide seasonal forecast information based on the experience from the H2020 CLARA project. The quality and value of the forecasts generated by CLARA services were assessed for five climate services utilizing the Copernicus Climate Change Service seasonal forecasts and responding to knowledge needs from the water resources management, agriculture, and energy production sectors. This joint forecast verification and service evaluation highlights various skills and values across physical variables, services and sectors, as well as a need to bridge the gap between verification and user-oriented evaluation. We provide lessons learnt based on the service developers’ and users’ experience, and recommendations to deploy such verification and evaluation exercises. Lastly, we formalize a framework for joint verification and evaluation in service development, following a transdisciplinary (from data purveyors to service users) and interdisciplinary chain (climate, hydrology, economics, decision analysis). The diagnostics provided by the joint assessment improve on individual quality and skill assessment by bringing forth more dimensions and an in-depth analysis of the sources of service value. Service co-production should thus consider simultaneously and iteratively the quality of the hydro-climate information provided and its value for decision-making to inform robust enhancement strategies. Such effort, however, requires for prolonged collaborations between social and climate scientists, service developers and service users, beyond the lifespan of common research projects and for building communities that allow such long-term collaborations.
Thundercloud high-energy radiation production by long streamers
Authors: Lehtinen Nikolai , Sarria David , Marisaldi Martino , Mezentsev Andrey , Østgaard Nikolai , Cummer Steven , Pu Yunjiao
Published: March 2024

The novel Streamer Parameter Model (SPM) [Lehtinen, 2021, doi:10.1007/s11141-021-10108-5] allows to quickly calculate the shape, velocity, and electric field of an electric streamer in air, without resorting to lengthy hydrodynamic simulations. A streamer propagates faster as its length grows. When the streamer length exceeds several meters, the velocity may become comparable to the speed of light, which necessitates correcting the model for relativistic effects. Such long streamers may describe the experimentally observed fast positive and negative breakdown. We propose that they may produce large quantities of relativistic runaway electrons, and therefore x-rays. This is facilitated by several conditions: (1) electric fields at the streamer tip may be sufficiently close to the so-called thermal runaway threshold (~30 MV/m), at which free electrons may accelerate from thermal energies up to relativistic energies; (2) in negative streamers, the energetic electrons are synchronized in velocity with the streamer front; (3) the streamer tip radius may exceed tens of centimeters, providing a large volume of the high field where the thermal runaway acceleration may take place.We apply SPM to long streamer propagation inside a thundercloud and calculate the relativistic runaway electron production, as well as radio, optical and x-ray radiation. The calculations are compared to the observations of Narrow Bipolar Events (NBE), Terrestrial Gamma Flashes (TGF), and luminous phenomena obtained during the recent ALOFT campaign.
Unraveling the Eddy-driven Heat Transport in the Agulhas Leakage Region
Authors: Wei Lansu , Wang Chunzai
Published: March 2024

The Agulhas leakage, which transports warm and salty Indian Ocean water into the Atlantic Ocean, plays a crucial role in global ocean circulation and climate. The mesoscale eddies from the leakage supply the primary source of heat and salt for the Atlantic meridional overturning circulation. This study combines eddy data with Argo profiles from 1993 to 2018 to investigate the three-dimensional structures of eddies, advancing our understanding of eddy-induced transport. Our analysis revealed that both the trapping and stirring processes of eddies influence eddy-induced transport. Anticyclonic eddies are found to transport heat in the meridional direction mainly through propagation (~60%). On the other hand, cyclonic eddies transport heat meridionally to the Atlantic Ocean primarily through the stirring of isotherms in the background field (~25%). These results further confirm that the stirring effect of cyclonic eddies is crucial for evaluating the impact of the Agulhas leakage on the Atlantic Ocean.
Managing the leaching of water-soluble herbicides in soils using eco-compatible nanocarriers
Authors: Tosco Tiziana , Granetto Monica , Fogliatto Silvia , Vidotto Francesco
Published: March 2024

Pesticide use plays a crucial role in achieving high crop yields in the context of a global population growth scenario. However, the extensive application of pesticides has progressively led to the contamination of environmental matrices, particularly soils and groundwater, posing potential risks to human health, flora, and fauna. Nanopesticides can be instrumental in mitigating pesticide pollution, especially for highly soluble and volatile active ingredients. They are formed by nanoparticles (nanocarriers) containing an active ingredient, sometimes shielded by a coating, and dispersed in a colloidal suspension. The nanoformulations proposed in this study utilize low-cost mineral materials (such as montmorillonite, zeolite, kaolin) and food-grade biopolymers to incorporate two distinct herbicides, namely dicamba and S-metolachlor, characterized by high solubility (and thus high migration potentian in the subsoil) and, for dicamba only, moderate volatility.The efficacy of the newly developed nanoherbicides in terms of reduced mobility in porous media, reduced persistency, and efficacy toward target weeds was assessed in the laboratory against the pure herbicide and commercial formulations containing the same active ingredients. Specifically, the mobility in porous media was tested through column transport experiments under both saturated and unsaturated conditions, using sand and standard soils (representative, respectively, of top soil and aquifers). These tests were conducted at various scales, ranging from small columns (1.6 cm diameter, 10 cm length) to a laboratory lysimeter (30 cm diameter, 70 cm length). Batch degradation tests in soils indicated comparable DT50 values for the nanoformulation and the commercially available product. The efficacy of the nanopesticides was also examined against conventional products in greenhouse settings through dose-response tests on selected sensitive weeds. The greenhouse tests revealed that clay-based nanoformulations do not impede the effectiveness of dicamba against target weeds, showing efficacy comparable to the commercial competitor for both dicamba and S-Metolachlor, although variations were observed depending on the treated species.Despite the small scale of the tests conducted in the laboratory and greenhouse, these initial results suggest the promising efficacy of the proposed nanoformulation approach in controlling the environmental spread of soluble herbicides without compromising efficacy against target species.This research was conducted within the Nanograss project, co-funded by the Compagnia di San Paolo Foundation. ReferenceGranetto M., Serpella L., Fogliatto S., Re L., Bianco C., Vidotto F., Tosco T. (2022). Natural clay and biopolymer-based nanopesticides to control the environmental spread of a soluble herbicide. Science of The Total Environment 806(3),151199, https://doi.org/10.1016/j.scitotenv.2021.151199
Observations of atomic oxygen in the MLT from a stratospheric balloon with the OSAS-B terahertz heterodyne spectrometer
Authors: Wienold Martin , Semenov Alexey , Hansen Peder , Hübers Heinz-Wilhelm
Published: March 2024

The Oxygen Spectrometer for Atmospheric Science on a Balloon (OSAS-B) is a heterodyne receiver for the thermally excited ground state transition of neutral atomic oxygen at 4.75 THz [1]. It has been shown that this transition is favorable for the determination of atomic oxygen in the mesosphere and lower thermosphere (MLT) region of Earth [2]. Due to water absorption, it cannot be observed from ground. Atomic oxygen is the dominant species in the MLT, and thus plays an important role for the chemistry and energy balance in the MLT region as well as for the deceleration of low-earth orbit satellites. OSAS-B uses a combined helium/nitrogen cryostat for the detector of the instrument, a superconducting hot-electron bolometer mixer, as well as for cooling the quantum-cascade laser, which serves as the local oscillator for heterodyne detection. A turning mirror allows for measurements at different vertical inclinations and for radiometric calibration against two blackbody sources. The first flight took place as a one-day flight in September 2022 from Esrange, Sweden in the framework of the EU-funded Hemera 2020 program. During the course of the flight, several hundred spectra for different elevation angles and azimuth directions were recorded. Preliminary results show a reasonable agreement with predictions from the current MSIS model (NRL MSIS 2.0/2.1). Besides, we are able to observe the spectral signatures of shear winds in the MLT as they are predicted by the horizontal-wind model (HWM 2014).[1] Wienold, M. et al. 48th IRMMW-THz, Montreal, Canada (2023), doi: 10.1109/IRMMW-THz57677.2023.10299165[2] Richter, H. et al. Commun Earth Environ 2,19 (2021), doi: 10.1038/s43247-020-00084-5
Impact of CO2 on water outgassing on rocky planets around TRAPPIST-1 – VPLANET/MagmOcV2.
Authors: Carone Ludmila , Barth Patrick , Barnes Rory , Helling Christiane , Chubb Katy , Bitsch Bertram
Published: March 2024

 VPLANET MagmOc is a versatile magma ocean model with erosion of water vapour in the open source VPLANET framework. Wepresent here a major improvement of this model that includes now a) thermal emission calculated with a full radiative transfer code and b) simultaneous outgasing of H2O and CO2 with full feedback on outgassing informed by planet formation models.We derived evolution tracks of an outgassed mixed H2O/CO2 atmosphere on TRAPPIST-1e, f and g. We find that all planets, in particular TRAPPIST-1 g, run the risk to evolve into Exo-Venuses with thick CO2 atmospheres after the magma ocean stage for an intial water budget of more than 10 terrestrial ocean (TO) of water within tens of million years.At the inner edge of the habitable zone, on TRAPPIST-1 e, we find that the combination of H2O atmosphere loss and CO2 outgassing reduces the thermal emission on the planet such that the magma ocean stage can be almost doubled from tens of million years to 80 million years for 10 TO intial water.We thus conclude that careful consideration has to be given to the various geophysical feedback effects as these can have a profound impact on the magma ocean evolution stage and thus on the overall water budget and the secondary atmosphere.
Towards monitoring climate change on a yearly basis using observational constraints.
Authors: Tessiot Octave , Ribes Aurélien
Published: March 2024

Climate change monitoring and adaptation policies require reliable and updated indicators about global warming. Reports of the Intergovernmental Panel on Climate Change (IPCC) provide updated indicators every 5 to 7 years, based in particular on the latest available data and evidence. In the last report, projections were derived from climate model simulations constrained by observations. Current warming was derived from observations averaged over the last 10 years, or again a combination of model and observations in attribution statements.Here we explore the possibility of updating present and future warming estimates on a yearly basis, by incorporating new observations to observational constraints. First, we show that adding the latest temperature observations each year leads to a continuous improvement in estimating warming projections. In particular, warming estimates are not affected by year-to-year internal variability. Second, regarding current warming, we show that observational constraints can be used to derive an estimate of the forced warming for the current year, without having to average over the last 10 years - as the IPCC does in its latest report. This provides an unbiased estimate of current warming, without adding further variance. Third, we show that updating model data can lead to a gap in the estimate of current and future warming, but this remains within the uncertainties we estimate. Finally, we argue that annual updates of current and future warming estimates provide accurate, robust, and reliable information about climate change, while remaining consistent with previous years' estimates.
Fault activation from up close
Authors: Meier Men-Andrin , Giardini Domenico , Wiemer Stefan , Cocco Massimo , Amann Florian , Spagnuolo Elena , Selvadurai Paul , Tinti Elisa , Dal Zilio Luca , Zappone Alba , Pozzi Giacomo , Jalali Mohammadreza , Gischig Valentin ,   FEAR science team
Published: March 2024

Our understanding of earthquake rupture processes is generally limited by the resolution of available observations. In all but exceptional cases, earthquake observations are made at comparatively large distances from the rupture itself, which puts a limit on what spatial scales can be resolved. At the same time, it is clear that small scale processes may play a crucial, if not dominant, role for various seismogenic processes, including rupture nucleation, co-seismic weakening and stress re-distribution.The Fault Activation and Earthquake Rupture ('FEAR') project aims at collecting and interpreting a multitude of earthquake-relevant observations from directly on and around the process zone of an induced earthquake. To this end, we attempt to activate a natural granitic fault zone in the BedrettoLab, at a depth of ~1km, after instrumenting the fault zone with a multi-domain and multi-scale monitoring system. The goal is to observe and study earthquake rupture phenomena in a natural setting, from unusually close distance.In this talk, we outline the project status, the science goals, and the plans for the main experiments, which are scheduled for the years 2024 - 2026. Notable milestones we report on includethe identification and detailed characterisation of the target fault zone
the beginning of niche and tunnel excavations
laboratory experiments that characterise the frictional and mechanical behaviour of both gauge material and host rock of the target fault zone
development of numerical models for 2D and 3D dynamic rupture propagation
development of tailored monitoring methods for seismicity, strain, temperature, pressure, bio-geo-chemistry and other relevant observables
development of remote experiment control methods
test stimulations in a nearby rock volume of similar geology, with an already existing monitoring system, where we tested the influence of pre-conditioning injection protocols
similar test stimulations in the same volume where we aim at triggering a larger event (target Mw~0)
active seismic experiments in an underground salt mine, to calibrate the very- to ultra-high frequency (1k Hz - 500k Hz) acoustic emission sensors
Together, these and other efforts constitute the necessary ingredients we need for interpreting the near-source observations that we will collect during the fault activation experiments.
Digitization and use of historical spectra from 1950/51 for the retrieval of various trace gases from the Jungfraujoch site (46.55N, 7.98E, 3580m)
Authors: Makkor Jamal , Palm Mathias , Buschmann Matthias , Mahieu Emannuel , Chipperfield Martyn , Notholt Justus
Published: March 2024

The Sphinx Observatory at Jungfraujoch (46.55N, 7.98E, 3580m) has been pivotal in atmospheric research, particularly atmospheric sounding, since its inception. This study revisits the observatory's pioneering work in the 1950s when a Pfund-type, dispersive spectrometer was utilized to capture infrared solar spectra, initially recorded on paper rolls. While the initial focus was on solar spectrum analysis, these historical spectra now offer a unique window into the atmospheric composition of the 1950s. The solar absorption spectroscopy at Jungfraujoch allows the retrieval of the atmospheric composition.Our research is twofold. First, we developed a specialized software for digitizing and calibrating these historical spectra, and making the spectra available for the scientific community. Second, using these digitized spectra, we determined the atmospheric concentrations of carbon monoxide (CO) and dichlorodifluoromethane (CFC12) from that era, comparing our findings with current model projections.The results show an intriguing disparity. For CO, the observed concentrations in 1950/51 were lower than those predicted by models. As expected, CFC12 levels were significantly lower than current levels, averaging at 0.75E15 molecules per square centimeter. This predates James Lovelock's first detection of CFCs in the 1970s and suggests a minor but detectable presence of CFC12 in the 1950s atmosphere. Ongoing efforts focus on extending this analysis to other trace gases, aiming to enrich our understanding of the atmospheric composition in 1950/51.
TEMPO Aerosol Retrieval Algorithm
Authors: Zhang Hai , Kondragunta Shobha , Ciren Pubu
Published: March 2024

TEMPO (Tropospheric Emissions: Monitoring Pollution) is a geostationary ultraviolet and visible spectrometer to monitor major air pollutants over north America.   The instrument was launched in April 2023 and the L1b data were available since October 17, 2023.   The sensor’s coverage of the O2B band (688nm) enables us to retrieve aerosol layer height (ALH).  At National Oceanic and Atmospheric Administration (NOAA) in the United States, we developed an algorithm to retrieve aerosol optical depth, aerosol type, and aerosol layer height from the TEMPO data.   Our approach involves the creation of a 0.05x0.05 degree database of surface reflectances for various bands, accounting for solar-satellite geometry.   To retrieve AOD, AOD and surface reflectance are varied until a solution is found that gives a minimum residual between derived and prescribed spectral surface reflectance ratio between blue and red bands. The surface reflectances at the O2B band are derived from retrievals of other bands using the surface reflectance ratio database. The ALH is determined by minimizing differences between the measured 688/670 bands' top-of-atmosphere (TOA) reflectance ratio and the calculated ratio.The retrieval algorithm was tested using the August-September 2020 TROPOMI data as a proxy over CONUS region where heavy smoke was observed.  The results show good AOD retrieval performance compared to ground-based Aerosol Robotic Network (AERONET) AOD:  the retrieved AOD has a correlation of 0.68, a bias of 0.11 and RMSE of 0.37 with respect to AERONET AOD.   Comparing to CALIOP ALH, the retrieved ALH has a correlation of 0.67, a bias of 0.91 km and an RMSE of 2.59 km.  Preliminary AOD retrieval from TEMPO data also demonstrates favorable agreement with AOD from the ABI instrument onboard GOES-East.Disclaimer: The scientific results and conclusions, as well as any views or opinions expressed herein, are those of the author(s) and do not necessarily reflect those of NOAA or the Department of Commerce.
Modelling Solutions for Ferricrete Formation and their Impacts on Topography
Authors: Fenske Caroline , Braun Jean , Guillocheau François , Robin Cécile
Published: March 2024

Ferricretes, or iron duricrusts, are hard iron layers, which predominantly develop in tropical and subtropical environments. They commonly cap elevated topographical features, potentially safeguarding old landscapes. The genesis of duricrusts is intricately tied to climatic conditions, particularly relying on intense seasonal precipitation cycles.Two hypotheses for iron duricrust formation exist: the hydrological or horizontal hypothesis and the laterisation or vertical hypothesis. In the first case, elements forming the duricrust are transported from distant areas and concentrated by hydrological processes. In the second case, the protolith is the underlying basement, and ferricretes form through leaching of soluble elements and compaction of less soluble ones.As no numerical model has been proposed for ferricrete formation until recently, we incorporated both formation hypotheses in a previously described numerical model for regolith formation (Braun et al., 2016).  The hydrological model was profusely described last year (Fenske et al. at EGU23), thus, we will concentrate on the laterisation model. In accordance with the second hypothesis, ferricrete formation follows laterisation of the regolith. During laterisation, the most soluble elements gradually dissolve and leach, resulting in the enrichment of non-soluble elements like iron and compaction. The model is characterized by two parameters: the time scales for iron enrichment τl and compaction τc, respectively. Various numerical scenarios were performed under diverse tectonic and climatic. The threshold Ωmin was determined to state formation or not of ferricretes.To calibrate the model, a case study has been defined in the southeastern part of Brazil, the Quadrilátero Ferrífero (QF) region. Ranging almost 7 000 km², this region is known for its abundance in iron ores and distinct topography with escarpments and high plateaus commonly topped by cangas. Cangas are a type of ferricrete which form from the weathering of BIFs (Banded Iron Formations). The oldest registered formations are up to 70 Ma old and seem to protect some of the mountain peaks for extended periods of time. Multiple scenarios are proposed to describe today’s landscape, with different climatic and tectonic parameters in play. With the help of the laterisation model, it is possible to model different scenarios to attempt to depict the formation of the QF.
Submarine landslides, tsunami and hydroacoustic waves: simulation and sensitivity analysis
Authors: Dubois Juliette , Imperiale Sébastien , Mangeney Anne , Sainte-Marie Jacques
Published: March 2024

We simulate the generation of acoustic and tsunami waves generated by submarine landslides using the linear model developed in [1]. The model is able to reproduce both acoustic and surface gravity waves generated by a moving source (e.g. earthquake, landslide) in a vertically stratified ocean.There are only a few studies that focus on the generation of acoustic waves by submarine landslides. In [2], the combined analysis of field data and simulations underline the presence of an interference pattern in the acoustic waves' spectrogram. The interference pattern has a time-varying bandwidth, which is a signature of the submarine landslide dynamics. In a previous work [3], we used the model developed in [1] to reproduce the interference pattern for a static source. Here we use the same model to simulate a submarine landslide in the 2D case. The simulations reproduce the time-varying bandwidth. They are then used to study the influence of two parameters on the acoustic spectrograms, namely landslide velocity and topography. Different velocity profiles available in the literature [4] are tested. For the topography, we use as reference the 2D case simulated in [1]. We also provide illustrations for the tsunami generation by the landslide. [1] Dubois J, Imperiale S, Mangeney A, Bouchut F, Sainte-Marie J. Acoustic and gravity waves in the ocean: a new derivation of a linear model from the compressible Euler equation. Journal of Fluid Mechanics. 2023;970:A28. doi:10.1017/jfm.2023.595[2] Caplan-Auerbach, J., Dziak, R. P., Bohnenstiehl, D. R., Chadwick, W. W., and Lau, T.-K. (2014), Hydroacoustic investigation of submarine landslides at West Mata volcano, Lau Basin, Geophys. Res. Lett.,  41,  5927– 5934, doi:10.1002/2014GL060964.[3] Dubois, J., Imperiale, S., Mangeney, A., and Sainte-Marie, J.: Simulation of the hydro-acoustic and gravity waves generated by a landslide, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15937, https://doi.org/10.5194/egusphere-egu23-15937, 2023. [4] Farin, M., Mangeney, A., de Rosny, J., Toussaint, R., & Trinh, P.-T. (2019). Relations between the characteristics of granular column collapses and resultant high-frequency seismic signals. Journal of Geophysical Research: Earth Surface, 124, 2987–3021. https://doi.org/10.1029/2019JF005258
How trees sway and what it tells us about their overall vitality
Authors: Roth Jana , Mora Karin , Al-Halbouni Djamil , Richter Ronny , Kattenborn Teja , Wieneke Sebastian Johannes , Bastos Ana , Weigelt Alexandra , Wirth Christian , Umlauft Josefine
Published: March 2024

Changing climate, especially the increase in frequency and intensity of extreme events such as heat waves and droughts, poses a significant challenge to the biosphere, threatening biodiversity overall and specifically exacerbating tree mortality. Countermeasures and management actions often prove insufficient due to delayed visual indicators of tree stress. Real-time monitoring of physiological and structural changes in tree characteristics and related abiotic parameters, such as sap flow, leaf angle, or soil moisture, plays a crucial role in tracking the trees’ overall vitality. However, conventional monitoring approaches are often expensive, require high maintenance and are therefore not feasible on a larger spatio-temporal scale.     In a groundbreaking approach, we propose to measure the seismic oscillation generated by tree sway under specific weather conditions, potentially reflecting tree vitality. Specifically, oscillations are related to material properties of leaves, branches, and trunks, which change when they become dry. Seismic measurements offer scalability and low maintenance, making them viable for extensive spatio-temporal coverage. Through integrated observations from dense seismic arrays, direct tree trait measurements, and meteorological parameters collected at the research arboretum (ARBOfun) during autumn 2023, we successfully isolated the seismic fingerprint of tree sway.However, the unique nature of this novel data introduces challenges, for example noise from human and animal activities, allowing for only time series snapshots. To overcome these challenges, we explored various time series and frequency related analysis methods to separate the tree signal from other influences.
The mechanism controlling air-sea CO2 exchange under different ocean circulation conditions, a case study from Iberian Margin
Authors: Ji Xuan , Yu Jimin
Published: March 2024

One of the critical features of deglaciations is the sudden increase in atmospheric CO2 levels. Regulating the Pleistocene atmospheric CO2 variations requires the involvement of oceanic carbon storage changes. However, the mechanisms and pathways for air-sea carbon exchanges remain elusive, partly resulting from the insufficiency of marine carbonate system proxy data with a robust age control beyond Termination I.The deglacial CO2 rise toward Marine Isotope Stage (MIS) 9e (Termination IV) started from 197.1 ppm to 300.7 ppm[1], representing the highest natural atmospheric CO2 recorded in the Antarctic ice cores over the past 800 ka[2]. Our high-resolution carbonate system records from the Iberian Margin with a robust age control suggest an expansion of southern-sourced Glacial Antarctic Bottom Water at the onset of the deglaciation, followed by a net release of CO2 from the Atlantic sector of the Southern Ocean. However, our results indicate a different ocean circulation pattern during Termination III, when atmospheric CO2 increases by 85 ppm[2]. Unlike Termination III, the north-sourced water seems to take a large proportion of the deep Atlantic Ocean during this period.References:[1] Nehrbass-Ahles, C. et al. (2020), Science vol. 369 1000–1005.[2] Bereiter, B. et al. (2015), Geophys. Res. Lett. 42, 542–549.
Anthropogenic influence on wintertime jet stream strength in the Atlantic sector. Is it real? Is it Atlantic SST mediated?
Authors: Piskozub Jacek
Published: March 2024

Wintertime variability of both the strength of the jet stream and the North Atlantic Oscillation (NAO) index have been correlated in decadal time scale. Both have positive trends since the 1960s which have been recently proposed to be connected to anthropogenic global warming. At the same time there is a rich literature explaining both the observed variability and also the discrepancy with circulation models in which the variability is usually much smaller. Among the proposed mechanisms were “tug-of-war” between the tropics and the Arctic lower troposphere and surface temperatures, Arctic amplification, polar vortex strength. However, none of those forcing can not explain the trends in all the studied period. The motivation behind the present study is to find a mechanism which can explain the variability and trend in the whole period of accelerated global warning, that is since the middle of the previous century. One possible candidate can be warming of the troposphere and cooling of the stratosphere, both well established results of the increase in greenhouse gas forcing. Together with the lowering of the tropopause altitude with increasing latitude, this results in warming south of the jet stream and cooling north of it, increasing the very gradient which sustains a thermal wind such as the jet stream. The results of early analysis show that the greenhouse related tropospheric warming / stratospheric cooling is a plausible candidate for the driver of changes in the wintertime jet stream strength and related NAO changes supporting the notion that NAO may head towards constant positive values. However the question remains why such changes are only visible in the Atlantic sector and not elsewhere in the mid-latitudes of the Northern Hemisphere. The multidecadal wintertime NAO changes seemed related with the AMO/AMV variability of North Atlantic SST values at least until the 1990s. This leaves the possibility that both Atlantic SSTs and greenhouse gas forcing are drivers of the variability in the wintertime jet stream strength. 