bluuebunny/crossref_metadata_2025 huggingface dataset:
P-T-t-EVOLUTION OF VARISCAN REMNANTS IN THE EASTERN ALPS: THE KAINTALECK METAMORPHIC COMPLEX
Authors: Karner-Ruehl Kevin , Hauzenberger Christoph A. , Skrzypek Etienne , Fritz Harald
Published: February 2023

The Eastern Greywacke Zone is composed of three Alpine nappes. From bottom to top these are (1) the Veitsch nappe (Early Carboniferous to Permian molasse), (2) the Silbersberg nappe with intercalated slivers of the Kaintaleck Metamorphic Complex and Permian phyllites and conglomerates as cover, and (3) the Noric nappe (mainly Ordovician to Devonian shelf sediments and Permian cover). All units experienced Eo-Alpine lower greenschist facies metamorphism. Due to the development of ductile shear zones during Alpine nappe stacking, the Kaintaleck Complex was dismembered and emplaced as lens-shaped bodies of 10-100m thickness that stretch from West (Kalwang, Upper Styria) to East (Gloggnitz, Lower Austria) below the Noric nappe of the Eastern Greywacke Zone. Lithologically, the Kaintaleck Complex is represented by a mafic suite, comprising amphibolite, garnet-amphibolite, greenschist and serpentinite, and a felsic suite that consists mostly of gneiss and mica-schist (some of them garnet-bearing). The felsic suite corresponds to metamorphosed clastic sediments and granitoids, whereas the mafic suite represents most likely a former oceanic crust. This work tries to constrain the P-T-t path of the Kaintaleck Metamorphic Complex by applying U-Th/Pb monazite and zircon dating and geothermobarometry. Based on whole rock geochemistry, amphibolites from the locality of Frauenberg represent tholeiitic basalts with an E-MORB affinity, whereas garnet-amphibolites, amphibolites and greenschists from the localities of Prieselbauer, Oberdorf, Unteraich, Kalwang, Arzbach and Schlöglmühl show a T-MORB signature. Samples from the localities of Stübminggraben and Utschgraben have a N-MORB affinity. Garnet-amphibolite samples show distinct plagioclase-epidote-rich symplectitic coronae, which are indicative of decompression from former eclogite-facies conditions. P-T estimations based on Zr-in-rutile thermometry and phengite barometry yield up to 720°C and 19 kbar for the felsic suite, and 700°C and 21 kbar for the mafic suite, both interpreted as peak metamorphic conditions. Monazite dating by EPMA in garnet-mica-schist from the localities of Prieselbauer, Arzbach, Schlöglmühl and Oberdorf, revealed weighted average U-Th-total Pb dates of 351 ± 4 Ma, 358 ± 16 Ma, 349 ± 3 Ma and 362 ± 6 Ma, which are interpreted as reflecting peak Variscan metamorphism. Monazite in these samples is partly replaced by an apatite-allanite-corona, related to monazite-breakdown due to Alpine lower grade metamorphic overprint. Preliminary LA-MC-ICP-MS U/Pb age dating results of zircon grains from a garnet-amphibolite from the Prieselbauer locality yield a Devonian mean date of 400 ± 4 Ma ascribed to the protolith formation.
An empirical study on the variability of luminescence ages for coeval loess samples
Authors: Constantin Daniela , Begy Robert , Vandenberghe Dimitri , Veres Daniel , Timar-Gabor Alida
Published: February 2023

An increasing number of studies exploit the advantages of a single-aliquot regenerative-dose protocol (SAR) for equivalent dose determination with sampling at relatively closely-spaced vertical intervals (of the order of 10-30 cm). The resulting ages are, at least in principal, ideally suited for age-depth modelling. The modelling, however, is made difficult owing to the variety and complex combination of uncertainties associated with luminescence dating. Moreover, we previously reported on a variability in age results for coeval loess samples that is significantly larger than expected and remains to be understood.In this study, we examine this problem explicitly by observing the degree of precision and accuracy that can be achieved by luminescence dating of multiple coeval loess samples of known age. The main goal is to improve our understanding of how luminescence ages are to be incorporated into age-depth models, thus increasing their robustness and accuracy.Fourteen samples were taken at closely-spaced horizontal intervals from loess deposits immediately over- and underlying the Campanian Ignimbrite/Y5 tephra layer (40Ar/39Ar dated to 39.2±0.1 ka), as exposed at a section in the Lower Danube Basin in southeastern Europe. Luminescence analyses were carried out using the single-aliquot regenerative-dose (SAR) protocol and OSL signals from 63-90 µm quartz fraction. We report an average age of 46 ka for the samples collected below the tephra layer and 40 ka for the samples collected above it. The individual random and systematic uncertainties contributing to the individual ages vary from 1.9 % to 5.4 % and from 6.0 % to 6.1 %, respectively. We obtain an improved overall precision on the age of the sedimentary context by calculating the weighted average age and combining the individual random and systematic uncertainties following Aitken (1985, Appendix B). Thus we report weighted average ages of 46 ka and 40 ka for the horizontally sampled sediment layers intercalating the ash layer and associated overall random uncertainties of 1.3 % and 1.1 %. The overall systematic uncertainties are 6.1 % and 6.0 %. The insights gained from this are discussed in relation to age-modelling studies of luminescence-dated paleoclimate archives, and loess deposits in particular.Keywords: luminescence dating; precision; random uncertainty; quartz
Lithospheric evolution of eastern Arabia
Authors: Wiesenberg Lars , Weidle Christian , Scharf Andreas , Agard Philippe , El-Sharkawy Amr , Krüger Frank , Meier Thomas
Published: February 2023

The geology of eastern Arabia is dominated by a vast cover of mostly Phanerozoic sedimentary rocks and little was known about the architecture of the middle and lower crust. On the easternmost margin, obduction of the Semail Ophiolite during late Cretaceous times is the youngest first-order tectonic process that shapes the present-day geology across the Oman Mountains in northern Oman and the eastern United Arab Emirates. Within the obducted units, Neoproterozoic to Cretaceous autochthonous rocks of the Arabian shelf are exposed in two tectonic windows and provide a detailed view of the geodynamic evolution of the shallow Arabian continental crust during and after obduction. A new, unprecedented 3-D anisotropic shear-wave velocity (Vs) model reveals that - prior to obduction - the assembly of the eastern Arabian lithosphere in Neoproterozoic times and its modification during the Permian breakup of Pangea strongly control the present-day lithospheric architecture. Building upon previous geodynamic models that were restricted to the upper crust, reconstruction of the entire lithospheric evolution resolves some key unknowns in eastern Arabia’s geodynamics:
The NNE-striking Semail Gap Fault (SGF) is primarily an upper crustal feature but another NE-striking deep crustal boundary zone west of the Jabal Akhdar Dome segments the Arabian continental crust in two structurally different units.

While Permian Pangea rifting occurred on both eastern and northern margins of eastern Arabia, large-scale mafic intrusions occurred mostly east of the SGF. Eastward crustal thinning localizes at the eastern limit of obducted units, east of which the lower crust is strongly intruded and likely underplated.

Late Cretaceous exhumation and overthrusting at the end of ophiolite obduction is the likely cause for crustal thickening below today‘s topography of the Oman Mountains.

Lithospheric thickness is ~200-250 km in central Arabia but only ~100 km below the Oman Mountains. Thinning of the continental lithosphere is attributed to late Eocene times, which explains contemporaneous basanite intrusions into the continental crust and provides a plausible mechanism for observed crustal-scale extension and the broad, margin-wide emergence of the Oman Mountains. Thus, uplift of the mountain range might be unrelated to Arabia-Eurasia convergence.
A spatial regression model to measure the urban population exposure to extreme heat
Authors: Massaro Emanuele , Caporaso Luca , Piccardo Matteo , Schifanella Rossano , Taubenböck Hannes , Cescatti Alessandro , Duveiller Gregory
Published: February 2023

Temperatures are rising and the frequency of heat waves is increasing due to anthropogenic climate change. At the same time, the population in urban areas is rapidly growing. As a result, an ever-larger part of humankind will be exposed to even greater heat stress from heat waves in urban areas in the future. In this research, we focus on studying the determinants of land surface temperature (LST) gradients in urban environments. We implement a spatial regression model that is able to predict with high accuracy (R2 > 0.9 in the test phase of k-fold cross-validation) the LST of urban environments across 200 cities based on land surface properties like vegetation, built-up areas, and distance to water bodies, without any additional climate information. We show that, on average, by increasing the overall urban vegetation by 3%, it would be possible to reduce by 50% the exposure of the urban population that lives in the warmest areas of the cities for the average of the three summer months, achieving a reduction of 1 K in LST. By coupling the model information with the population layer, we show that an 11% increase in urban vegetation is necessary in order to obtain a reduction of 1 K in the most populated areas, where at least 50% of the population live. We finally discuss the challenges and the limitations of greening interventions in the context of available surfaces in urban areas.
Consequences of the spatial configuration of Carbon Dioxide Removal for its potential to withdraw atmospheric CO2
Authors: Adam Moritz , May Matthias M. , Kleinen Thomas , Samanta Arya , Rehfeld Kira
Published: February 2023

At the current decarbonization rate, we are set on a path towards re-shaping a substantial share of land for carbon dioxide removal (CDR) over the following decades. However, existing Earth system models which could help to quantify the character of resulting CDR side effects and their consequences for the cumulative CO2 removal do not yet resolve dynamic CDR cover in space. Here, we embark on shedding light on this CDR uncertainty space, scrutinizing CDR impacts in spatial simulations with a comprehensive Earth system model. Assuming CDR to be driven by solar irradiation in the style of photovoltaics, our model is the first to simulate an idealized approach to land-based CDR with its physical, biospheric, and land use couplings on a grid box scale. We analyze dynamic CDR simulations for spatial deployment scenarios according to the country-wise burden of past CO2 emissions, to livelihood constraints, and to optimal irradiation conditions. Shared socio-economic pathways drive the overall global CDR use for a range of potential future emission scenarios. Aside from these spatio-temporal scenarios, the simulations also cover different ways of releasing excess energy from the solar-to-carbon conversion, permitting either local cooling through carbon storage, heat dissipation resulting from system losses or co-benefits for energy production. Based on simulation ensembles for the different scenarios, we quantify Earth system impacts of CDR and their consequences for CO2 removal if grid-scale feedbacks are properly resolved. With new spatially resolved CDR representations in Earth system models we will be able to test CDR-induced Earth system dynamics and CDR promises in greater detail than with existing globally forced projections. This spatially explicit modeling strategy could also open a way toward more comprehensive modeling strategies which include consequences for land use decisions on CDR.
Tropopause inversion layer and its correlation with relative humidity
Authors: Reutter Philipp , Köhler Daniel , Spichtinger Peter
Published: February 2023

To better understand our climate and weather system, knowledge of the processes in the upper troposphere and lower stratosphere (UTLS) is crucial.An important element in the UTLS region is the tropopause inversion layer (TIL). The TIL is a region of extraordinarily high or overshooting static stability just above the tropopause. Since its discovery, a couple of hypothesis were developed to explain the origin and formation of the TIL. In addition to dynamic mechanisms, such as baroclinic waves, a radiative forcing mechanism is considered, where ozone and water vapor are contributing to the TIL formation and persistence.To investigate the latter mechanism further, we examine the correlation between the relative humidity with respect to ice, as a measure for water vapor in the UTLS region, and the TIL.Based on high-resolution radiosonde data of the German Weather Service (DWD) from 2011 to 2019, we are investigating how TIL properties such as the height, strength or thickness of the TIL layer change with temperature and relative humidity over ice. We also investigate seasonal differences of the above-mentioned properties. Furthermore, the results are also compared with ERA5 reanalysis data. We can show that ERA5 can reproduce relevant properties of the TIL as compared to the radiosondes. Thus, ERA5 data can be used for extending the investigations to other geographical locations.
Bayesian calibration of a 1D hydrodynamic model used as a rating curve in a tidal river: Application to the Lower Seine River, France
Authors: Mendez Rios Felipe , Le Coz Jérôme , Renard Benjamin , Terraz Theophile
Published: February 2023

Hydrometric stations may be influenced by the sea tide, disrupting the stage-discharge relation and making it difficult to estimate discharge through a traditional rating curve. Twin-gauge stage-fall-discharge (SFD) rating curves, based on a flow friction equation and stage and water slope measurements, are a possible alternative, but they were found to perform poorly when the tide effect is strong. To capture the complex flow dynamics, including flow reversal, an approach via a 1D hydrodynamic model is proposed.To set up the model, the cross-sectional geometry, friction coefficient, upstream discharge and downstream water level are required. In hydrodynamic modelling, the friction coefficients are the main calibration parameters and spatial changes of roughness combined with unsteady flow make their manual calibration difficult. Moreover, the understanding and quantification of uncertainties associated with data and model is an important step of the calibration process. Therefore, an automatic calibration of friction coefficients is proposed via Bayesian inference. In terms of numerical tools, the selected 1D hydrodynamic code is Mage, developed by INRAE, solving the 1D Saint-Venant equations for subcritical, transient flows. Likewise, the Bayesian Modeling (BaM) framework (https://github.com/BaM-tools) is used to specify prior information and estimate friction coefficients and their uncertainty, using stage and discharge observations.The case study is the Lower Seine River in France, because it comes as a simple hydraulic model with a strong tidal effect with gauging campaigns and stage records available. Discharge time series of the Seine at Poses and of the Eure, the only significant tributary, are specified as upstream boundary conditions.  The downstream boundary condition is the stage time series of the Seine at Saint-Léonard, reflecting the tidal signal. Calibration data include stage records at different stations and times, and ADCP discharge measurements at Rouen during several tidal cycles.For all reaches, a lognormal distribution with 95% probability interval [33; 49] is used as a prior for the Strickler coefficient. Bayesian estimation then provides their posterior distributions, represented by a large number of samples generated by means of a Markov Chain Monte Carlo (MCMC) algorithm. These samples can be used to identify optimal “maxpost” coefficients (maximizing the posterior density), but also to quantify and propagate their uncertainty. Thereafter, a propagation is performed to estimate the stage and discharge series of all cross-sections along with their uncertainty.This study aims to provide an alternative solution for the continuous monitoring of discharge from stage records and upstream discharges in tidal rivers in order to improve flood forecasting, warning systems and the understanding of tidal-influence on hydrometric stations.
Investigation of 1-D and 3-D Crustal seismic velocity structure in the broader area of Crete (Greece)
Authors: Karakonstantis Andreas , Vallianatos Filippos
Published: February 2023

The island of Crete is located in the Southern Aegean Sea, at the central part of the Hellenic Trench. The increased seismic activity in the region as a result of the convergence of the Eurasian and African tectonic plates highlights the importance of improving our knowledge on local seismotectonic features that play a key role in the seismic hazard. In this work, we used over than 1400 manually revised events from 2018 to 2022 in order to obtain both local and regional 1-D velocity models. The final output was put into the Seismic Inversion procedure, using body-wave (P, S) travel-time data in order to perform a detailed analysis and correlation of medium to large-scale (in km) anomalies with the activation of local and regional faults. Crete's central region exhibited complex shallow structures, whereas in deeper tomographic slices (> 40 km depth) a smoother, more continuous image, was revealed. This result may have been caused by the upward migration of fluids due to the subduction of Tethys oceanic lithosphere. As a result of the final dataset analysis, and exploring the most recent aftershock sequences (e.g. 2021-2022 Arkalochorion earthquakes) the research area's prevailing seismotectonic processes were investigated in more detail, clarifying the relationship between shallow and intermediate-depth earthquake activity. Acknowledgements: This work was supported by the Hellenic Mediterranean University, contract 104/18-10-2022, in the frames of the «Study of GEophysicalsystems and their laboratory equivalents towards the understanding Of Earthquake Early Warning Systems (GEOWS)». 
NISAR Soil Moisture retrievals using the Time-Series Ratio Algorithm
Authors: Bindlish Rajat
Published: February 2023

The NISAR mission will provide global data sets of Earth land surface dynamics that are critical to multiple Earth Science disciplines including observations of ecosystem carbon and water cycles. Soil moisture is a surface hydrosphere state variable and plays a key role in global terrestrial hydrology.  It controls the partitioning of water and energy fluxes at the land surface.  NISAR's L-band SAR backscatter measurements are similar to those planned for the L-band radar of the Soil Moisture Active/Passive (SMAP) mission, although at much finer spatial resolution.NISAR soil moisture using a time-series ratio algotrithm is currently being developed. The final NISAR soil moisture product will have 200m spatial resolution with 12-day exact revisit time. A time-series ratio algorithm was implemented using UAVSAR (SMAPVEX12 field experiment) and SMAP radar observations. In this paper, the performance of the time series ratio algorithm was assessed using in situ observations. Performance of the soil moisture retrieval algorithm was also assessed for dual polarization and quad-polarization observations modes.
Multi-element compound-specific isotope analysis of chlordecone during abiotic transformation reactions
Authors: Prieto-Espinoza Maria , Malleret Laure , Höhener Patrick
Published: February 2023

Chlordecone (CLD; C10Cl10O) is an organochlorine pesticide extensively used between 1960s and 1990s in the French West Indies (FWI). Its massive use led to soil and river pollution which prompted its ban in 1993. CLD has a bis-homocubane structure and various chlorine atoms making it highly recalcitrant in the environment. To date, several environmental compartments of the FWI continue facing the legacy of CLD pollution. This study aims at improving the monitoring of the degradation (or recalcitrance) extent of CLD in the soils of the FWI following in situ chemical reduction (ISCR). Multi-element compound-specific isotope analysis (ME-CSIA) was used to identify changes of stable isotopes of CLD (i.e., 13C/12C and 37Cl/35Cl) produced during distinct abiotic reductive transformation reactions. Reductive transformation of CLD was tested in abiotic microcosms in the presence of either zero-valent iron, ascorbic acid, vitamin B12, or persulfate activated by microwave irradiation. CLD transformation was evidenced by the detection of several hydrochlordecones (after losses of one or two chlorine atoms) under all conditions. Enrichment of the 13C isotopes of CLD relative to 12C revealed distinct signatures during transformation reactions of CLD to maximum Δδ13C of +7.2 ‰. A novel stable Cl isotope analysis was performed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS). Ongoing Cl isotope analysis may establish a multi-element assessment in which abiotic CLD degradation pathways may be distinguished based on stable C-Cl signatures. Altogether, our results may provide an improved strategy to elucidate CLD degradation in contaminated soils of the FWI.
Lithosphere-asthenosphere interaction as the source for intraplate deformation in the Gulf of Guinea
Authors: Almeida Jaime , Riel Nicolas , Neres Marta , Mohammadigheymasi Hamzeh , Custódio Susana , Dumont Stephanie
Published: February 2023

Despite extensive research, intraplate earthquakes and required intraplate deformation remain relatively unexplained. To explore this problematic, we tested the possibility that these could derive from the dynamic interaction between the lithosphere and the upper mantle. This was performed by conducting a thorough geophysical exploration of a region with both low plate velocities and clear asthenosphere dynamics, specifically the Gulf of Guinea (GOG) and adjacent Western Africa.In this work, we developed 3D numerical geodynamic models of the asthenosphere-lithosphere interaction in the GOG, ran with the state-of-the-art LaMEM modelling code. To assess the contribution of individual intraplate deformation sources, we tested various initial/boundary conditions namely: (a) the spreading rate of the individual segments of Central Atlantic mid-ocean ridge, (b) the presence/absence of weak zones, such as the Romanche or Central-African shear zones, as well as (c) the stress contribution by an active mantle plume head with varying width. Seismicity data was utilized as a criterion to assess the validity of the modelled stress/strain localization sites.Our results suggest that intraplate deformation within the GOG is mostly controlled by the spreading rate of the mid-ocean ridge, with different localization sites deriving from their relative proximity to the shear zones and plume head. This work aims to expand our knowledge of intraplate deformation mechanisms and to contribute towards improving seismic hazard assessment away from plate boundaries.This work was supported by the European Union and the Instituto Dom Luiz (IDL) Project under Grant UIDB/50019/2020, and it uses computational resources provided by C4G (Collaboratory for Geosciences) (Ref. PINFRA/22151/2016). It was also partly supported by the Fundação para a Ciência e a Tecnologia (FCT) in the content of the Project SHAZAM “Sismicidade e Perigosidade da Margem Atlântica sub-Saariana,” with the reference PTDC/CTA/GEO/31475/2017; POCI-01-0145-FEDER-031475, co-financed by FEDER-COMPETE/POCI 2020.
Modelling the early Cenozoic Antarctic ice sheet oxygen isotope ratio and implications for the benthic δ18O change
Authors: Van Breedam Jonas , Huybrechts Philippe , Crucifix Michel
Published: February 2023

At the Eocene-Oligocene Transition (~34 Ma), ephemeral ice sheets grew into a large continental-scale Antarctic ice sheet. During the late Eocene there is evidence for short-lived, continental-scale glaciations in the benthic oxygen isotope record, as well as geomorphic evidence pointing towards large-scale glaciations on Antarctica. Here, the modelled mean oxygen isotope ratio of these early Cenozoic Antarctic ice sheets is presented. Since benthic oxygen isotopes are a proxy for both the deep sea temperature and the ice volume stored on land, it is possible to estimate the benthic oxygen isotope change once the mean oxygen isotope content of the ice sheet is known.The modelled ice sheet oxygen isotope ratio of the late Eocene Antarctic ice sheets are strongly dependent on the size of the modelled continental-scale ice sheet, which in turn is determined by the bedrock. The ice sheet volume expansion during the Priabonian Oxygen Isotope Maximum (at around 37.2 Ma during the late Eocene) results in a modelled benthic oxygen isotope change between 0.3‰ and 0.55‰, sufficient to explain the observed excursions in the benthic oxygen isotope records. At the Eocene-Oligocene Transition, the modelled benthic oxygen isotope change due to ice sheet growth is found to be between 0.65‰ and 0.75‰. The remainder 0.45‰ to 0.55‰ of the observed benthic oxygen isotope change should therefore have been caused by oceanic cooling.
Mechanisms of nocturnal soil CO2 uptake influenced by a succession of biological soil crusts in drylands
Authors: Kim Minsu , Lopez-Canfin Clément , Lázaro Roberto , Sánchez-Cañete Enrique P. , Weber Bettina
Published: February 2023

Many dryland soils absorb atmospheric CO2 at night. Despite the relatively small annual carbon (C) uptake, ranging locally from 1 to 10 g C m-2, it may have large-scale effects, as drylands cover almost 45% of the Earth’s land surface. This process might contribute to the global missing C sink of 3.1 ± 0.9 Pg C year-1. As dryland soils have high inorganic C contents compared to organic C, mechanisms of the nocturnal CO2 uptake likely involve both biotic and abiotic processes that are tightly coupled to water availability. Biological soil crusts (hereafter, biocrusts) cover about 30% of global drylands and provide favourable physico-chemical hotspots for this C exchange mechanism. In this study, we present a mechanistic model of inorganic C binding that is enhanced by the activity of biocrust communities. The model results show good agreement with field measurements of the soil-atmosphere CO2 exchange dynamics under contrasting conditions of water availability and temperature in the Tabernas Desert (Spain). We further show that inorganic C sequestration rates at night vary, depending on the successional stages of biocrusts. Our findings have the potential to substantially improve the often-overlooked processes of dryland systems in the global C cycle. By unravelling the mechanisms occurring along the succession of biocrusts, this study highlights the roles of soil biological agents in mitigating CO2 emissions in a drier future.
Intercomparison of machine learning algorithms for downscaling of coarse resolution temperature over complex terrain like the Alps
Authors: Bhakare Sudheer , Dal Gesso Sara , Venturini Marco , Zardi Dino
Published: February 2023

The output of Global climate models has a coarse resolution, which is unsuitable for practical applications like agricultural services. Downscaling is the approach used to create fine-resolution data from coarse one. There are two main approaches to downscale climate model outputs: Dynamical Downscaling (DD) and Statistical downscaling (SD).  In DD, higher-resolution climate models called regional climate models (RCM) are used. RCM use lower resolution climate models as boundary conditions and physical principles to reproduce local weather. These RCMs use physical equations and computational calculations to estimate local climate, making them computationally intensive and time-consuming. On the other hand, for SD, a statistical relationship is developed between the historically observed climate data and the climate model output for the same historical period. The relationship is used to develop future climate data. In recent years Machine learning-based statistical downscaling approaches have gained popularity due to their learning abilities from large datasets.We have developed a artificial neural network-based machine learning algorithm to downscale coarser resolution temperature to a finer one over Trentino–South Tyrol (north-eastern Italian Alps). In addition to that, considering the high correlation of elevation with temperature, elevation data of high resolution (1km x 1km) from the digital terrain model is used to train the model. We have developed different neural network models with additional complexity in terms number of layers in the model and compared them with a benchmark standard linear model and nonlinear model such as support vector regression for their performance.
Laboratory experiment for initiation of wood motion on mobile-bed by using IMU sensor
Authors: Chen Yi-Cheng , Chen Su-Chin
Published: February 2023

ABSTRACT   In recent years, Taiwan has suffered from large-scale sediment-related disasters frequently caused by climate change induced extreme rainfall events. Fresh wood was usually recruited with large-scale sediment-related disasters and trapped in channels. Once a flash flood occurs, wood accumulated in the river consequently travels, threatening the safety of structures in the river. Furthermore, driftwood forms log jams leading to river blockage and backwater, causing overflooding. Therefore, realizing the initiation of motion mechanism of driftwood helps prevent driftwood disasters.According to previous studies on the initiation of wood motion, driftwood interacts with sediment and results in sliding, rolling, pivoting and floating motion modes dependent on discharge and riverbed conditions. To explore the motion mode of the initiation of wood motion on a mobile bed, this study conducts a flume experiment using driftwood equipped with an IMU (Inertial measurement unit) sensor that measures the posture of driftwood’s motion in the Eular Angle. According to the IMU’s data, the above four motion modes can be interpreted. Meanwhile, using the laser scanner to establish the digital elevation model and explore the correlation between sediment and driftwood motion on different mobile-bed conditions.
Multiscale analysis of physical rock properties at Stromboli Volcano: what controls the frictional properties?
Authors: Alcock Thomas , Vinciguerra Sergio , Benson Phillip
Published: February 2023

Stromboli volcano, located in the north-easternmost island of the Aeolian archipelago (Southern Italy) and well known for its persistent volcanic activity, has experienced at least four sector collapses over the past 13 thousand years. The most recent activity resulted in the formation of the Sciara del Fuoco (SDF) horseshoe-shaped depression and a tectonic strain field believed to have promoted flank collapses and formed a NE / SW trending weakness zone across the SDF and the western sector of the island. The tectonic strain field interplayed with dyking and fracturing appears to control the episodes of instability and the onset of slip surfaces. This study presents new data identifying areas of damage that could promote fracturing via remote sensing and rock friction measurements taken on rocks around the SDF and the coupled “weak” zone. We have carried out a multiscale approach by integrating satellite and microscale observations with frictional tests carried out in triaxial configuration on cm scale slabs. Key units have been sampled on the field (Paleostromboli, Vancori and Neostromboli) with reference to SDF and the weak zone. Direct-shear tests in triaxial configuration were carried out to explore the frictional and seismic properties using rectangular basalt slabs at 5 – 15 MPa confining pressure in dry and saturated conditions, while recording acoustic emissions (AE) via two Piezo-Electric Transducers. The sliding velocity was changed to acquire rate and state friction parameters (RSF). Preliminary results show a variation in the friction coefficient (m) between 0.55 and 0.9 with a general m decrease with increasing confining pressure and saturation. RSF parameters a-b (0.1 < a-b < 0.1) and steady state friction coefficient (mss) (0.6 < mss < 0.9) are controlled by changing sliding velocity, confinement and by the physical properties of each unit, in particular the porosity.  AE key attributes, such amplitude, frequency and duration and their evolution confirm the relation to sliding velocity, confinement and porosity. Ongoing post mortem SEM analysis are aiming to assess the impact that textural features, such porosity, crystal distribution and glass groundmass for the different units have on the evolution of crack damage and their control on the frictional properties. Quantitative crack density analysis will be carried out using the Matlab tool box FracPaQ on the microstructures to quantify fractures properties and highlight which mechanical features (for example crystals or pores) control the development of asperities/stress concentration. This finding can be related to the field scale fracture density analysis, providing quantitative support for the identification of structurally weak zones across the SDF and constraint the mechanical behaviour of the fractured zones prone to instability. 
Topside ionosphere effective plasma scale height characterization through CSES-01 satellite Langmuir Probes observations
Authors: Pezzopane Michael , Pignalberi Alessio , Coco Igino , Consolini Giuseppe , D'Angelo Giulia , De Michelis Paola , Giannattasio Fabio , Piersanti Mirko , Tozzi Roberta
Published: February 2023

The topside ionosphere embraces the region extending from the F2-layer electron density peak to the overlying plasmasphere. In this region the electron density monotonically decreases at a vertical rate driven by the plasma scale height, which in turn depends on both the plasma chemical composition and the physical state. Since an accurate and thorough knowledge of the plasma chemical and physical properties at these altitudes is not available with the required spatial and temporal coverage, an effective plasma scale height is usually inferred from topside electron density measurements and used for empirical modelling purposes.In this work, we aim at characterizing the effective plasma scale height (H0) above the F2-layer peak  through in-situ electron density (Ne) observations by Langmuir Probes (LPs) on-board the China Seismo-Electromagnetic Satellite (CSES-01). Additional information is given by the International Reference Ionosphere (IRI) model. CSES-01 is a sun-synchronous satellite flying with an orbital inclination of 97.4°, an altitude of ~500 km, and descending and ascending nodes are at ~14 local time (LT) and ~02 LT, respectively. Calibrated CSES-01 LPs Ne data recorded in the years 2019-2021 provides the information in the topside ionosphere, while IRI provides the Ne values at the F2-layer peak (NmF2) for the same time, latitude, and longitude sounded by CSES-01. These two Ne set of values are used as anchor points to infer H0 through the topside representation given by the NeQuick model. By exploiting the CSES-01 dataset for the years 2019-2021 we deduced the global H0 behavior for daytime (~14 LT) and nighttime (~02 LT) conditions, for low solar activity conditions. Results obtained with CSES-01 observations are compared and validated with corresponding ones provided by COSMIC-1 radio occultation measurements for similar diurnal and solar activity conditions.
Linking macroplastic deposition to riverbank characteristics
Authors: Hauk Rahel , van Emmerik Tim H.M. , van der Ploeg Martine , Boonstra Marijke , de Winter Winnie , Teuling Adriaan J.
Published: February 2023

Rivers transport, and store a large share of the global plastic pollution. Riverbanks are one of the river compartments where macroplastic litter is deposited and retained. Different factors influence macroplastic deposition on riverbanks. Retention related factors such as riverbank features, and supply related factors, such as hydrometeorology or land-use. Riverbank macrolitter along the Dutch Meuse has been quantified, characterized, and removed biannually since 2017. At each monitored riverbank, macroplastic and other litter items were collected along a 100 m section and classified in over 100 specific litter categories. We assume that after each monitoring round all litter is removed, and that the litter sampled in the following round has accumulated in the time between rounds. This monitoring dataset is analyzed to identify riverbanks with plastic accumulation rates continuously below or above average, and the specific characteristics of these identified riverbanks. Furthermore, correlations are investigated between macroplastic deposition and individual riverbank features and river morphology, such as types of riparian vegetation, or curvature of the river. These correlations are tested for the total amount of plastic litter, but also categories grouped by plastic characteristics such as potential source, density, size, or flexibility. This is done based on the hypothesis that plastic litter items with different characteristics are associated to different processes of plastic emission and deposition. For example, items with low or high density, or different levels of flexibility. Items with low and high densities are transported differently, because their density is lower or higher than the density of water. Items with a high level of flexibility, such as soft plastic foils, have a higher potential for entanglement in vegetation, and a lower potential for remobilization, compared to items with a low level of flexibility. The aim of this study is to identify riverbank characteristics that explain high plastic accumulation rates.
Phytoplankton physiology controls global ocean biogeochemistry (and climate)
Authors: Chien Chia-Te , Pahlow Markus , Schartau Markus , Li Na , Oschlies Andreas
Published: February 2023

The similarity of the average nitrogen-to-phosphorus ratios (N:P) in marine dissolved-inorganic and particulate-organic matter indicates tight links between those pools in the World Ocean. Here we analyse the sensitivity of marine biogeochemistry to variations in phytoplankton N and P subsistence quotas in an optimality-based ecosystem model coupled to the UVic Earth system model. Our results reveal distinct feedbacks between changes in the N and P quotas, N2 fixation, and denitrification that loosen the coupling between dissolved and particulate N:P.  We demonstrate the importance of particulate N:C and P:C for regulating dissolved N:P on the global scale, with oxygen concentration being an important mediator. Our analysis also reveals a potential interdependence between phytoplankton stoichiometry and global equilibrium climate conditions.
Evaluating ensemble post-processing for probabilistic energy prediction
Authors: Lerch Sebastian
Published: February 2023

Probabilistic forecasts based on ensemble simulations of numerical weather prediction models have become a standard tool in weather forecasting and various application areas. However, ensemble forecasting systems tend to exhibit systematic errors such as biases, and fail to correctly quantify forecast uncertainty. Therefore, a variety of post-processing methods has been developed to correct these errors and improve predictions [1]. In particular, machine learning methods based on neural networks have been demonstrated to lead to substantial improvements compared to classical statistical techniques [2].While post-processing can successfully correct the biases and dispersion errors in the weather variables, its effect but has not been evaluated thoroughly in the context of subsequent forecasts, such as wind and solar power generation forecasts and it is not obvious how to best propagate forecast uncertainty through to subsequent power forecasting models. Therefore, the work presented here will evaluate multiple strategies for applying ensemble post-processing to probabilistic wind and solar power forecasts. We use Ensemble Model Output Statistics (EMOS) as the post-processing method and evaluate four possible strategies: only using the raw ensembles without post-processing, a one-step strategy where only the weather ensembles are post-processed, a one-step strategy where we only post-process the power ensembles and a two-step strategy where we post-process both the weather and power ensembles. The presentation is based on recent work in Phipps et al. (2022) [3] and ongoing other work.References[1] Vannitsem, S., et al. (2021). Statistical Postprocessing for Weather Forecasts - Review, Challenges and Avenues in a Big Data World. Bulletin of the American Meteorological Society, 102, E681–E699.[2] Rasp, S. and Lerch, S. (2018). Neural networks for post-processing ensemble weather forecasts. Monthly Weather Review, 146, 3885–3900.[3] Phipps, K., Lerch, S., Andersson, M., Mikut, R., Hagenmeyer, V. and Ludwig, N. (2022). Evaluating ensemble post-processing for wind power forecasts. Wind Energy, 25, 1379-1405. 
Alpine subduction and intraplate deformation along the Iberian Atlantic margins
Authors: Cadenas Martínez Patricia , Welford J. Kim , C. Duarte João , Fernández-Viejo Gabriela , Somoza Luis
Published: February 2023

The structure of Iberian Atlantic margins resulted from multiple Mesozoic rift events and subsequent contractional deformation occurring from the Upper Cretaceous to Cenozoic during the Alpine Orogeny. Along the southern Bay of Biscay, the North Iberian margin shows various styles of contractional deformation, ranging from mild reactivation of pre-existing extensional structures, halokynetic-related processes, to wedging and underthrusting. The Biscay accretionary wedge developed as the major structure at the base of the continental slope in the central and western parts of the North Iberian margin, which are part of the western branch of the Pyrenean-Cantabrian Orogen, together with the Cantabrian Mountains onshore. The wedge is interpreted to continue from the western North Iberian margin, where incipient subduction has been proposed, to the Galicia Margin further to the southwest. Along the West Iberian margin, thrusting and related folding and halokynetic-related processes focused contractional deformation.In this work, we describe the seismo-stratigraphy, and we map contractional structures along the North Iberian and West Iberian margins based on the interpretation of 2D seismic reflection profiles. We identify and describe structural domains along the extinct subduction zone along the North Iberian margin, describe the structure of the fossil Biscay accretionary wedge, and identify and map different styles of Alpine contractional deformation along the North Iberian and West Iberian margins. We also describe the pre-existing Mesozoic rift structure in order to analyse the overprint between different rift architectures and contractional styles of deformation. The overall goal is to define different styles and stages of Alpine contractional deformation along Iberian Atlantic margins during the first phases of the convergent cycle preceding or leading to subduction. 
Vs model for Oran city, obtained by joint-inversion of dispersion and HVSR curves
Authors: saadi ahmed , Issaadi Abdelouahab , Semmane Fethi , Yelles–Chaouche Abdelkrim , Galiana-Merino Juan José , Layadi Khalissa , Chimouni Redouane
Published: February 2023

AbstractThe city of Oran, which is located in the northwest of Algeria, in the Lower-Cheliff basin, has experienced several earthquakes in the past. Therefore, the characterization of its subsurface is crucial for a better assessment of the seismic hazard. Single-station ambient vibration measurements at 193 sites and array measurements at 15 sites have been analyzed with HVSR and F-K techniques, respectively, for the soil investigation.The HVSR curves showed a variation of the fundamental frequency peak between 0.3 and 7.4 Hz, increasing from east to west, and reaching a maximum amplitude of ~6. Rayleigh wave dispersion curves were obtained by F-K analysis. Joint-inversion of the dispersion and HVSR curves provided a shear wave velocity model and an estimate of the bedrock depth. The models showed 3 layers of sediments overlying the bedrock. The shear-wave velocity (Vs) of the softer sediments varies between 280 and 580 m/s, and at bedrock it varies between 1600 and 2500 m/s. The latter reached a maximum depth of 1050 m northeast of the city. In addition, these results were used to calculate the soil vulnerability factor (Kg), and the Vs30 in the entire area. Finally, a soil classification and a regression law between the fundamental frequency and the depth were proposed for the whole city.
Can learning regression features by computer vision improve the generalisation of geostastistical interpolators?
Authors: Kirkwood Charlie , Economou Theo , Odbert Henry , Pugeault Nicolas
Published: February 2023

Recent approaches for large-scale mapping of continuous environmental variables by combining ground observations, remote sensing and machine learning have proposed incorporating computer vision capabilities into the model, so that potentially-complex regression features may be learned automatically from covariate datasets, such as of terrain elevation and other satellite imagery (e.g. see Kirkwood et al 2022; 'Bayesian deep learning for spatial interpolation in the presence of auxiliary information').Here we present new research using national-scale land-surface geochemical data to explore and compare how the incorporation of computer vision for automatic feature learning affects the predictive performance of geostastistical interpolators both within and beyond the spatial extents of the study areas in which ground observations are collected. We attempt to characterise empirically how well the predictive performance of different models is preserved with increasing distance from training observations in order to provide insights into the value of incorporating computer vision capabilities into geostatistical models, compared to more traditional approaches.
Predicting transport properties in porous and fractured media, how fractal-based models can help petrophysicists?
Authors: Jougnot Damien , Guarracino Luis , Soldi Mariangeles , Rembert Flore , Luo Haoliang , Solazzi Santiago , Thanh Luong Duy
Published: February 2023

Since the great paradigmatic revolution initiated by Mandelbrot, we know that fractals are ubiquitous in nature. From coastlines to plant growth, fractal mathematics help us to describe and quantify many of nature’s properties. In the same way, the fractal theory can be applied to porous and fractured media. In recent decades, numerous research studies have shown that fractal theory provides a solid framework to describe the properties of geological media. Based on advanced physical knowledge at the microscale, it is possible to use fractal patterns to describe transport properties in porous and fractured media. Fractal laws can be applied to describe the size distribution of pores and fractures, fracture widths, and pore irregularities, but also to relate these pore sizes to pore tortuosities. In this contribution, we review the significant advances that have been made in the field of petrophysics by applying fractal mathematics to describe fundamental petrophysical properties such as porosity, permeability, electrical conductivity, thermal conductivity, and electrokinetic and electroosmotic coupling coefficients. These new petrophysical models are based on the upscaling procedure applied to different fractal objects such as the Sierpinski carpet, Koch curves, Pigeon holes, and Menger sponge, among others. Among the interesting results obtained by means of fractal-based petrophysics, one can derive transport properties of saturated or partially saturated media, above and below freezing temperature, and considering hysteretic behavior and reactive media dissolution/precipitation processes. Integrating these fractal-based petrophysical relationships into the laboratory or field-scale, numerical simulations are now opening a wide range of potential avenues for progress in near-surface and reservoir geophysics.