bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of factors influencing the construction of a check dam to reduce damage caused by debris flow
Authors: Lee Seungjun , An Hyunuk , Kim Minseok
Published: February 2023

The check dam is one of the most effective countermeasures to reduce the damage caused by debris flows. While several previous studies have tried to find the priority factor of check dam construction, there are still limitations in terms of quantitive analysis for figuring out the factor of check dam influencing debris flow damages. This study analyzed the most influential factor to assess the best location for the mitigation effect through numerical simulations, which are on the Raemian apartment at Mt. Umyeon in Seoul and Gallam-ri in Gangwon-do, the Republic of Korea, in 2011 and 2019, respectively. The simulation results were quantitatively analyzed by Spearman's rank correlation method. As a result, it was found that the topographical components are more reasonable than flow characteristics in the construction of the check dam. In particular, the check dam constructed at the point which could store more debris revealed the best performance in mitigation effect.
Functional Inversion of Glacier Rheology from Ice Velocities using ODINN.jl
Authors: Bolibar Jordi , Sapienza Facundo , Maussion Fabien , Lguensat Redouane , Pérez Fernando , Wouters Bert
Published: February 2023

Inversion methods play an important role in glacier models, both to calibrate and estimate parameters of interest (e.g. Glen's coefficients). However, inversions are usually made for each glacier individually, without using any global information, i.e. without deriving general laws governing the spatiotemporal variability of those parameters. The reason behind this limitation is twofold: the statistical challenge of making constrained inferences with multiple glaciers, and the computational limitation of processing massive glacier datasets. Machine learning powered with differential programming is a tool that can address both limitations.
 
We introduce a statistical framework for functional inversion of physical processes governing global-scale glacier changes. We apply this framework to invert a prescribed function describing the spatial variability of Glen’s coefficient (A). Instead of estimating a single parameter per glacier, we learn the parameters of a regressor (i.e. a neural network) that encodes information related to each glacier (i.e. long-term air temperature) to the parameter of interest. The inversion is done by embedding a neural network inside the Shallow Ice Approximation PDE - resulting in a Universal Differential Equation - with the goal of minimizing the error on the simulated ice surface velocities. We previously had shown that this hybrid model training is possible thanks to the use of differential programming, enabling differentiation of a PDE, a numerical solver and a neural network simultaneously. In this work we upscale this approach to include larger datasets and with the goal of learning real empirical laws from observations.
This framework is built inside ODINN.jl, an open-source package in the Julia programming language for global glacier evolution modelling using Universal Differential Equations. ODINN exploits the latest generation of ice surface velocities and geodetic mass balance remote sensing products, as well as many preprocessing tools from the Open Global Glacier Model (OGGM).
A Bayesian multi-model framework for structure selection and parameter estimation for lumped parameter modeling in karst hydrology.
Authors: Sivelle Vianney , Cousquer Yohann , Jourde Hervé , Mazzilli Naomi
Published: February 2023

Lumped parameter modeling in karst hydrology has been widely developped in the last decades. Uncertainty in model conceptualization, which often leads to one unique model structure, is frequently neglected. This issue is particularly important for karst hydrology, where hydrological systems are highly heterogenous and information about the structure is difficult to obtain. In this work, we delopped a Bayseian multi-model framework that allows to calibrate simulteanously a set of model structure and associated parameters. This constitutes a significant step forward compared with classical calibration approaches that allow (i) to provides an ensemble of predictions considering both structural and parametric uncertainties, and (ii) to avoid epistemic error due to model structure selection, wich is generally influenced by the subjective conceptualization of the karst hydrological system by the modeler. The methodology is illustred with a Bayesian inference procedure among a large range of lumped parameter model structure considered for the simulation of discharge at fontaine de Vaucluse karst spring (southern France).
Bridge the gap: Linking social vulnerability and adaptive behaviour
Authors: Han Sungju , Masson Torsten , Köhler Sabrina , Kuhlicke Christian
Published: February 2023

Individual adaptation is essential for achieving community resilience as well as coping with residual risks that have not been addressed by current structural schemes for reducing flood risks. At the same time, it also implies that individuals should have the resources and capacity to protect themselves. So far, this has been interpreted in the social vulnerability concept as accounting only for income, wealth, or other materially relevant factors, showing how much vulnerable people are exposed to more risk. However, individual behavioural adaptability has hardly been included in the current vulnerability assessment.In light of this, this study proposes a novel way to expand and link social classes using well-established social vulnerability indicators (i.e. income, education, and job status) with socio-psychological and lifestyle elements theoretically and empirically known to influence individual protective behaviour. We conducted a bias-adjusted three-step Latent Class Analysis (LCA) with covariates (socio-psychological and lifestyle elements) and distal outcomes (adaptive behaviour). A household survey (n = 1,753) conducted between June and July 2020 in 11 cities in Saxony, Germany, was used.The preliminary result shows that socio-psychological and cultural factors that influence individual decision-making on proactive adaptive behaviour co-vary with social classes based on their resource endowment. It also revealed that the lower class tends to have less implementation of costly adaptation methods, for example, structural measures on housing, while less costly measures did not make a significant difference. As a result, we recommend that, in addition to the lack of material endowment, which can be associated with an increased risk of exposure, individual inaction of protective behaviour motivated by socio-psychological traits be considered for social vulnerability.
Estimating sheet flow velocities using quinine as a fluorescent tracer in low luminosity conditions: laboratory and field experiments
Authors: Zehsaz Soheil , de Lima João L. M. P. , de Lima M. Isabel P. , Isidoro Jorge M. G. P. , Martins Ricardo
Published: February 2023

This study presents a technique based on the use of quinine as a fluorescent tracer, to estimate sheet flow velocities over various surface coverings (e.g., bare; mulched; vegetated; paved) in low luminosity conditions (e.g., night; twilight; shielded environments). Quinine glows when exposed to UVA light and in the concentrations used is not harmful to the environment. Experimental work was conducted for studying sheet flows in the i) laboratory (using a soil flume), over bare and mulched surfaces, and ii) field, over vegetated and paved surfaces. Flow velocities were estimated based on the injection of a quinine solution into the water flow.  In these experiments, dye and thermal tracer techniques were used as a benchmark for assessing the performance of the quinine tracer. Optical and infrared cameras were used to record the movement of the tracers’ plumes in the flow. The surface velocity of the flow was estimated by tracking the tracers’ plumes leading-edge and calculating their travel distance over a certain time lapse. Overall, the visibility of the quinine tracer was better in comparison to the dye tracer. However, under some circumstances, lower than the visibility of the thermal tracer. Nonetheless, the results show that all three tracers yielded similar estimations of the flow velocities. Therefore, when exposed to UVA light the quinine tracer can be useful to estimate sheet flow velocities over a wide variety of soil and urban surfaces in low luminosity conditions. Despite some inherent limitations of this technique (e.g., invisible under bright light conditions or heavy mulched/vegetated cover; need of a UVA lamp), its main advantage is the high visibility of the quinine fluorescent tracer under UVA light for fade light conditions (e.g., night; twilight; shielded environments such as close conduits), which creates new opportunities for tracer-based surface flow velocity measurements in surface hydrology studies.
Clouds boost microbial activity in the atmosphere
Authors: Amato Pierre , Péguilhan Raphaëlle , Rossi Florent , Joly Muriel , Baray Jean-Luc , Deguillaume Laurent , Enault François
Published: February 2023

The atmosphere transports biological material including living microorganisms. Whereas their survival is impaired during atmospheric transport due to desiccation and UV notably, certain organisms maintain metabolic activity and interact with physicochemical processes. This has especially been studied in clouds for its potential impacts on chemical processes such as the degradation of organic compounds and the oxidant capacity. However, it is still unknown whether the functioning of airborne microorganisms in clouds is specific and differs from the rest of the atmosphere; this question was investigated here. We developed a metagenomic/metratranscriptomic approach to investigate the in-situ functioning of airborne microbial communities and decipher its environmental drivers, notably the impacts of the presence of condensed water in clouds. Aerosol and clouds samples were collected from puy de Dôme mountain summit (1465 m asl, France) using series of high flow rate impingers, into a fixative agent to preserve nucleic acids (DNA and RNA), i.e. the identity and instantaneous functional signature of organisms. A bioinformatics pipeline was developed specifically to analyze these unprecedented and complex datasets. Comparative analyses revealed that clouds are genuine oases for living microorganisms in the atmosphere: although their microbial biodiversity is similar as that during clear atmospheric situations, droplets provide shelters especially against oxidative stress, which is found to characterize the metabolic functioning of airborne microbes in dry aerosols. The presence of condensed water boosts many biological functions, and functions related with starvation toward carbon and nitrogen notably indicate increased biological needs and evidence the existence of numerous interactions with chemical processes and atmospheric biogeochemical cycles. Regarding microbial ecology, the reactivation of metabolic functions in airborne microorganisms transiting through clouds could facilitate their settlement in their new environment.
Ozone damage in plants: 7 years of study in a free-air experimental facility (FO3X)
Authors: Baesso Moura Barbara , Manzini Jacopo , Hoshika Yasutomo , Paoletti Elena
Published: February 2023

Ozone (O3) is a toxic oxidative air pollutant with significant detrimental effects on natural vegetation and crop species. Free-air controlled exposure (FACE) facilities provide an ideal tool for O3 effect studies, producing realistic results. The O3 Free-Air Controlled Exposure (FO3X - FACE) facility, located in Sesto Fiorentino, Italy, and established in 2015, is an AnaEE (Analysis and Experimentation on Ecosystems) European research platform. The facility permits the exposure of plants to three levels of O3 concentrations (1.0, 1.5, and 2.0 times the ambient concentration, denoted as AA, x1.5AA, x2.0AA, respectively), with main environmental variables continuously monitored. Over the years, the accumulated exposure over 40 ppb hourly concentrations (AOT40) was calculated and used as an exposure-based O3 index. The stomatal conductance (gsto) model, based on the multiplicative algorithm, was used to parameterize the gsto of 12 species (7 deciduous: Oxford poplar, Quercus robur, Quercus pubescens, Sorbus aucuparia, Alnus glutinosa, Vaccinium myrtillus, I-214 poplar, and 5 evergreens: Quercus ilex, Phillyrea angustifolia, Arbutus unedo, Pinus halepensis, Pinus pinea), in order to calculate the hourly stomatal O3 flux (Fst), and thus the phytotoxic O3 dose above an hourly threshold y of uptake (y = 1, POD1) used as a flux-based O3 index. Our studies have evaluated the effect of O3 in gas exchange parameters as light-saturated photosynthesis (Asat / R2 POD1 = 0.46 vs. AOT40 = 0.20) and stomatal conductance (gsto /R2 POD1 = 0.18 vs. AOT40 = 0.18), as well as for the induction of specific visible foliar injury (VFI / R2 POD1 =0.40 vs. AOT40 = 0.32) and biomass loss (Bloss / R2 POD1 = 0.50 vs. AOT40 = 0.22). We demonstrate that species-specific flux-based O3 index POD1 is more relevant compared to the exposure-based O3 index AOT40, showing the importance of comprehending the mechanism of O3 damage to plants after the uptake through stomata. Our research has also been improving the derivation of experimentally based critical levels (CLs) for the protection of forests and crops vegetation from O3 damage.
Transitions between use/land cover classes and burnt areas in Europe
Authors: Tonini Marj , Parente Joana , Koutsias Nikos , Pereira Mário
Published: February 2023

Wildfires play a fundamental role in Land Use/Land Cover (LULC) change dynamics by burning vegetation in forested and rural areas and by affecting human infrastructures. Conversely, LULC can disturb fire regime by altering vegetation cover, conditioning subsequent transitions, and acting on fuel loads and continuity. Though there is an evident mutual influence between wildfires and LULC changes, a rigorous quantification of their reciprocal effects in Europe has never been performed before. To fill this gap, in the present study we developed a methodology allowing the evaluation of different indicators for the quantitative assessment and a better understanding of the transitions among LULC classes and Burnt Areas (BA) that occurred in Europe within the last two decades (2000 – 2020).Our analyses revealed that the two LULC classes which had experienced major changes were Forests (44%), and Scrubs and/or herbaceous vegetation associations (32%). As a general trend, within the five European Mediterranean Countries more prone to wildfires (Portugal, Spain, France, Italy, and Greece) we found a decrease in the classes Forests and Arable land, and an increase in Scrubs and/or herbaceous vegetation associations, suggesting the impact of wildfires in shaping the natural and rural landscape. This assumption was better evaluated and confirmed by the following analyses, performed at both the European and national levels. Results showed that most of the BA have occurred in Forests (42% for the entire Europe), with a predominance in Coniferous forests; the subsequent transitions from BA were generally to Transitional woodland/shrub or again to BA. This last indicates a high frequency of wildfires in a given area, while the first transition can be partially due to the regeneration/recolonization of the vegetation after a wildfire event. Outcomes for the single countries followed almost the same trend.Overall, our results confirm the existence of a strong relationship between wildfires and LULC changes in Europe, which have been quantified in the present study. These findings are in line with previous research and provide a deep insight into the process at the global and local levels, paving the way for further analyses on fire intensity and frequency with coupled environmental elements of land cover and climate changes.
Analysis of gap filling techniques for GRACE/GRACE-FO terrestrial water storage anomalies in Canada
Authors: Bringeland Stephanie , Fotopoulos Georgia
Published: February 2023

Since its launch in early 2002, datasets from the Gravity Recovery and Climate Experiment (GRACE) and its 2018 follow-on mission (GRACE-FO) have become indispensable for monitoring terrestrial water storage. GRACE-derived terrestrial water storage anomalies (TWSA), especially when used in conjunction with other water budget datasets (i.e., precipitation, evapotranspiration, surface runoff), provide insight into groundwater and glacier mass fluctuations. With over 20 years of observations, long-term statistical analysis reveals water storage trends, however, the 11-month gap between the two missions must be filled. The goal of this presentation is to compare four gap filling methods over Canada, namely: extreme gradient boosting, artificial neural networks, an automated machine learning (ML) algorithm (AutoML), and projection onto convex sets (POCS). The GRACE mascon product (RL06M.MSCNv02) released by the Jet Propulsion Laboratory was used, and all data were bounded by GRACE availability (April 2002 - March 2022) at the time of the study. Reconstruction of TWSA data in Canada required consideration of glacier surface mass balance models derived from the GMAO Modern-Era Retrospective Analysis for Research and Applications, Version 2 reanalysis, and the Randolph Glacier Inventory. Nine sets of nation-wide hydrological and climatic parameters were used as predictors for the machine learning models: GRACE average seasonal signal, TWSA from the GLDAS Catchment Land Surface Model, precipitation, air temperature, glacier surface mass balance, ocean tides, the North Atlantic Oscillation, the Multivariate ENSO Index, and sea surface temperature. Results indicate that ML algorithms can fill the gap with mean normalized root mean square errors ranging from 6 – 13% and AutoML performs the best with 2.5 cm equivalent water height (EWH). The purely mathematical signal synthesis POCS method resulted in approximately 4.0 cm EWH for some basins. Filling the gap between missions allows for more comprehensive terrestrial water storage trend analysis, including basin-by-basin analysis, which is ongoing over Canada.
Partial control of the Gulf of Mexico dynamics by the current feedback to the atmosphere
Authors: Larrañaga Marco , Renault Lionel , Jouanno Julien
Published: February 2023

The feedback of ocean surface currents to the atmosphere (CFB) has been shown to correct long-lasting biases in the representation of ocean dynamics by providing an unambiguous energy sink mechanism. However, CFB effects on the Gulf of Mexico oceanic circulation, mainly dominated by the Loop Current and large anticyclonic eddies that shed from it), remain unknown. Here, twin ocean-atmosphere eddy-rich coupled simulations, with and without CFB, are performed over 24 years (1993-2016) to assess to which extent CFB modulates the dynamics of the Gulf of Mexico. We show that CFB damps the mesoscale activity by roughly 20% over the Gulf of Mexico through the eddy killing mechanism and the associated transfer of momentum from mesoscale currents to the atmosphere, but also by modifying the production of eddy kinetic energy via barotropic and baroclinic instabilities. This energy adjustment results in increasing the mean Loop Current penetration into the Gulf of Mexico and plays a key role in determining the shedding of Loop Current Eddy and their subsequent preferential trajectories and properties.
Persistence of initial lithological heterogeneity to deep subduction conditions: Implications for the rheology of the subduction zone interface
Authors: Tokle Leif , Behr Whitney , Braden Zoe , Cisneros Miguel
Published: February 2023

The subduction zone interface is a shear zone of varying thickness that defines the boundary between the subducting slab and overriding plate. The rheology of this shear zone controls several important aspects of subduction dynamics, but accurately estimating its rheology can be complex due to the wide range of subduction materials and their varying rheological properties. Of particular importance is the relative strengths of metasedimentary and metabasic rocks at various temperature and pressure conditions. To better understand these rheological contrasts in naturally deformed rocks, we are conducting field and microstructural work in the Eclogite Zone in the Tauern Window, Austria. The eclogite zone preserves intercalated metamafic (metabasalt and metagabbro) and metasedimentary (quartzite, garnet mica schist, marble and calc-schist) rocks that were subducted and exhumed to the surface as a single structural unit. Using high resolution drone imaging, 2D structural mapping, and 3D structural modeling, we have documented map-scale relationships between metamafic and metasedimentary rocks in the Eissee region near Matrei. Our mapping demonstrates that the mafic eclogites consistently define slabs, lenses and boudins of up to 2 km in along-strike length and 0.2 km in thickness, embedded within the metasedimentary units, all of which are relatively uniformly deformed to very high strain. This suggests that eclogitized metamafic rocks persisted as rheological heterogeneities within the subduction channel through both the subduction and exhumation paths. Additionally, we are using microstructural observations to document the deformation mechanisms of individual rock units and to understand the weakening mechanisms that allowed some of the eclogites to break down from boudins to strongly foliated layers intercalated with the metasediments. At the interface between select metasedimentary and eclogite units there is a marked rheological change in eclogite rheology, likely due to fluids leached from the metasedimentary rocks, resulting in strain localization and increased foliation development within eclogite layers from meter to micron length scales. Integration of our mapping, outcrop, and microstructural observations will provide insights into the length scales of rheological heterogeneity on the deep interface and large-scale geodynamics of subduction through influencing the bulk viscosity of the interface.
The long-term evolution at Krafla Volcanic System, Iceland, by time-lapse microgravity.
Authors: Martinez Garcia Ana , Gottsmann Joachim , Rust Alison
Published: February 2023

The Krafla Volcanic System (KVS) in the Northern Volcanic Zone (NVZ) in Iceland last erupted between 1975 and 1984, during an eruptive period called “the Krafla Fires”. The KVS is composed of a restless caldera, an array of scoria cones along a fissure swarm and is among the best-studied volcanic systems due to the exploitation of its geothermal potential. In 2009, the Icelandic Deep Drilling Project (IDDP) encountered a shallow rhyolitic magma body at 2.1 km depth beneath the caldera. To date, no geophysical method has been able to image this magma body at Krafla within the top 4 km of the crust.  Here we present new micro-gravity data collected in June and July 2022 across a 14-station network of benchmarks in the KVS. Micro-gravimetry is a relative method that records changes in gravity between a reference and a series of benchmarks over both space and time to investigate subsurface mass or density changes via time-series analysis and modelling.  Our 2022 survey highlights negative gravity differences of benchmarks located in the centre of the caldera with respect to a reference located to the south and outside the caldera. The most negative values are found in its eastern part. Positive gravity differences can be found south of the southern caldera wall along a set of past eruptive fissures.  The next steps in data processing include data reduction for deformation effects to link the new data to previous joint deformation and micro-gravity surveys conducted at the KVS since 1965. This should enable us to quantify the long-term evolution of the KVS over more than 50 years providing unprecedented insights into its inner workings.
Spatial patterns of stable isotopes in precipitation in Switzerland for the use in hydrological and hydrogeological applications
Authors: Pelzmann Valentina , Leis Albrecht , Schuerch Marc , Reszler Christian
Published: February 2023

The stable isotopes of the water molecule, oxygen-18 and deuterium, provide an ideal tracer for water movement and offer a broad range of possibilities to study different processes in the water cycle. To be used in hydrological analyses and modelling the isotope data in precipitation as an “input” function has to be known for the particular catchment or point of interest. This paper presents the development and application of a method interpolating – on a monthly basis – stable isotope data in precipitation of the isotope observation network in Switzerland (ISOT), a module of the NAQUA National Groundwater Monitoring. Several influencing variables (e.g., topographical parameters, climate variables) are tested in a multi-regression framework, and the residuals are interpolated by the use of ordinary kriging. The different variants are tested by cross-validation, splitting the sample in two periods. The tests also provide information about regional differences of the interpolation quality in Switzerland, from which recommendations are made to densify the existing network. Maps of oxygen-18 and deuterium in a 500 m raster are delivered for selected months and years. As a further step in this study, for particular measurement sites of groundwater and surface water with known catchments, the “input” function is determined and compared to the measurements to (i) further validate the interpolation method and, (ii) to improve existing hydrological and hydrogeological information about the location of the recharge area and mean travel times. Also, the “input” functions can be used in hydrological modelling of combined water movement and solute transport in water quality studies.
Scaling analysis of wave profiles
Authors: Gao Yang , Schmitt Francois , Hu Jianyu , Huang Yongxiang
Published: February 2023

In the field of wind-wave interaction, scaling features for both wind and waves are often found experimentally. Several theoretical explanations of the scaling law for wind speed and sea surface wave height have been advocated, while a theoretical consideration for the significant wave height (Hs) is still lacking. In this work, we considered a long-term (more than 20 years) and high sampling frequency (about 0.78 Hz) wave profile data collected by buoys provided by Coastal Data Information Program (CDIP). The scaling features for Hs and for the absolute value of the wave profile are evident in the sense of the Fourier power spectrum. The same scaling features were obtained for frequencies below 10-4 Hz, with a scaling exponent close to 3. While the spectrum for wave profile shows a plain-like distribution under the frequency around 0.02 Hz due to the band pass filter. Furthermore, measured Hs is well overlapped with the absolute value of the wave profiles, which indicates that the amplitude modulation is still preserved after band pass filtering, and that might be the reason for the existence for the scaling features for Hs.
Using Time Series Data and Machine Learning Estimating Agricultural Groundwater Extraction in Huwei Town, Taiwan
Authors: Tseng Yu Kai , Yu Hwa Lung
Published: February 2023

Groundwater is an essential source of water in Taiwan, and its long-term overuse has resulted in water resource problems that have become a potential crisis in the Zhuoshui River Basin. This overuse of groundwater may also lead to subsidence, which can have significant consequences for the area and its infrastructure. The lack of complete observations of groundwater extraction in Taiwan due to historical factors has made it difficult to accurately understand and manage the amount of water being taken, particularly for agricultural purposes.In view of this, this study uses time series data from 87 agricultural groundwater wells in Huwei Town, Yunlin County from January 2016 to July 2017, and time series data on agricultural well electricity usage in the Changshui River Basin, combined with other attribute data, to understand farmers' water pumping behavior using data mining methods and to estimate the amount of water taken in the Huwei area using machine learning.This study obtained the spatial and temporal distribution of groundwater withdrawals in the Huwei area in 2018.
New constraints on the geological evolution of the SE corner of the Arabian Plate (NE Oman)
Authors: Bauer Wilfried , Jacobs Joachim , Callegari Ivan , Scharf Andreas , Mattern Frank
Published: February 2023

The Saih Hatat Dome is a tectonic window in northeastern Oman with a NW-SE extension of <95 km and an E-W extension of <50 km, rimmed by the allochthonous Samail Ophiolite and the underlain nappes composed of sedimentary rocks from the Neo-Tethyan Hawasina Basin. Rocks within the window were affected by an upper Cretaceous high- to ultra-high pressure/low-temperature eclogite- and blueschist-facies metamorphism.Stratigraphically, the Saih Hatat Dome contains a several kilometer thick basal (“Autochthonous A”) sequence from what is believed Cryogenian Hatat schists to the Ediacaran Hiyam dolostone, unconformably overlain by 3400 m Cambro-Ordovician siliciclastics. This basal sequence is separated by a so-called ‘Hercynian’ unconformity from Permian to Jurassic overall shelf carbonates (“Autochthonous B”). In the eastern part of the window, intense Cretaceous deformation and metamorphism makes it difficult to identify this stratigraphic subdivision.New U-Pb zircon LA-ICP-MS data from a quartzdiorite dyke, intruding the basal part of the Hatat schists gave a crystallization age of 845 +2/-4 Ma. Thus, the basal part of the Hatat schists is Tonian in age and older than the Cryogenian/Ediacaran strata of the nearby Jebel Akhdar Dome and Huqf area, 40 km to the west and 300 km to the south, respectively.Two blueschist-facies tuffites from eastern Saih Hatat contain concordant detrital zircons, ranging in age between c. 530 and 2872 Ma with age clusters around 750 to 850 Ma and 1010 to 1164 Ma. The latter ages are not known from a source on the Arabian Plate and might be derived from an Indian source.Based on the new results, we suggest a subdivision of the Saih Hatat stratigraphy with a Tonian accretionary wedge (Hatat schist) which might be coeval with igneous intrusion from the Ja’alab area, an Ediacaran carbonate platform, and a Cambrian sedimentary basin, unconformably overlain by upper Cambrian/Ordovician quartzites.
Emplacement mechanisms of pegmatites in the Chotonagpur Granite Gneiss Complex, Eastern India: insights from laboratory experiments
Authors: Biswas Uddalak , Mitra Atin Kumar , Mandal Nibir
Published: February 2023

The Chotonagpur Granite Gneiss Complex (CGGC) is crisscrossed by numerous syn-tectonic pegmatitic bodies in the entire terrain. We chose a set of locations in the CGGC to minutely study their structural characteristics, with an objective to explore their emplacement mechanisms. The field evidences show periodic wavy interfaces of pegmatites with the walls, indicating their emplacement in an overall ductile regime. We conducted laboratory experiments to replicate the pegmatitic intrusion processes in analogue models. In these experiments, analogue materials of complex rheology (visco-elastic and visco-elastoplastic) were chosen as hosts, and viscous fluids (water and commercial low-viscosity oil) were injected into the host at varying volumetric flow rates (VFR), 0.100 ml/sec to 1.670 ml/sec. The experimental results show a systematic transition from rupturing to wall-instability-driven fluid intrusion mechanisms with increasing VFR. By combining field and laboratory observations, this study suggests that pegmatites can eventually attain varying geometrical patterns depending on the dominance of these two competing intrusion mechanisms. We also consider the injecting fluid to host viscosity ratio as an additional factor, and performed experiments with varying viscosity ratios: (i) low (oil and UST gel), (ii) moderate (coloured water and UST gel) and (iii) high (coloured water and gel wax). This rheological factor significantly modulates the rupturing versus instability mechanisms in determining the three-dimensional intrusion geometry. We complement this investigation with a fractal analysis of the intrusion trajectories, showing specific fractal dimensions (D) for the two intrusion mechanisms. Finally, a model is proposed to establish a linkage between the intrusion shape and the modes of failure.
Precision Irrigation Scheduling through High Frequency Data Monitoring. Implementation in Apple Orchard Cultivations - central Greece.
Authors: Tsakmakis Ioannis , Babakos Konstantinos , Chatzi Anna , Pisinaras Vassilios , Brogi Cosimo , Bogena Heye , Dombrowski Olga , Panagopoulos Andreas
Published: February 2023

Pinios River Basin in central Greece (PRB) is region of highly productive agriculture where irrigation intensification and climate change have caused a significant depletion of groundwater resources. In the framework of the EU-Horizon 2020 project ATLAS, a precision irrigation scheduling service has been developed that aims at improving irrigation water management at the field scale. Such service is intended to protect crops from water stress by keeping the soil moisture (SM) in the root zone above the maximum allowable deficit (MAD). The presented approach is developed in two highly instrumented apple orchard pilot fields (~1.2 ha extent each) located at the Pinios Hydrologic Observatory ILTER site in PRB. In each pilot field and for two consecutive cultivation periods (2021 and 2022), intensive monitoring of meteorological parameters plus SM in 12 locations and at three depths (5, 20, 50 cm) was performed. To determine the time and volume of the next irrigation event, the forecast of meteorological variables for the next six days provided by the Global Forecast Model (GFS) was included in the service. The irrigation service performance was evaluated via comparison of the model estimated crop evapotranspiration (ETc) values against the SM content distribution monitored by the cluster of the installed SM sensors. The potential service contribution to reduce irrigation water consumption was assessed via comparison of the modelled irrigation water demands against the actual water consumption monitored at the irrigation blocks that divide each field. Statistical metrics demonstrate a good agreement between modeled crop evapotranspiration (ETc) and the monitored SM dynamics as captured by the SM sensors. Comparisons between the calculated irrigation demands and the actual water consumption monitored at the irrigation blocks of the pilot fields show that irrigation water applied in the fields may be reduced from 15% up to 50% or more in some instances, without considerably impacting crop health and yield. On the contrary, significant gains may be achieved on water saving and consequently on energy consumption to abstract irrigation water, thus contributing considerably to the region’s water-energy-food nexus sustainability.
PiecewiseInference.jl: a machine learning framework for inverse ecosystem modelling
Authors: Boussange Victor , Vilimelis Aceituno Pau , Pellissier Loïc
Published: February 2023

In contrast to purely data-driven statistical models, process-based ecosystem models have the potential to extrapolate beyond observed dynamics and predict their response to global change. Yet, the predictive power of process-based ecosystem models has been limited in practice because of issues with the estimation of the model parameter values and because of model inaccuracies. While inverse modelling techniques can make use of observation data to improve the estimation of parameters and, combined with model selection techniques, improve model inaccuracies, process-based ecosystem models are dependent on numerous parameters, are strongly nonlinear, and their numerical integration is computationally expensive. These characteristics, together with the nature of available observation data that may consist of shallow, incomplete and noisy time series, as well as the difficulty to obtain the model sensitivity to the parameters, have challenged the use of inverse modelling and model selection techniques in ecosystem modelling. Here, we present a machine learning (ML) framework relying on a segmentation method combined with state-of-the-art optimizers and automatic differentiation to perform inverse ecosystem modelling. The segmentation method regularizes the likelihood landscape, while the latter techniques, traditionally used in the field of artificial intelligence, greatly improve the efficiency of the inference process. We introduce PiecewiseInference.jl, a software package written in the Julia programming language that implements the ML framework, and evaluate its performance in recovering the dynamics of simulated chaotic food-webs. We show that it can efficiently estimate parameters and subsequently provide reliable forecasts based on noisy, incomplete and independent time series. Using model selection techniques, we further show that the ML framework can provide accurate statistical support for the true generating model among several candidates. We plan on utilizing PiecewiseInference.jl with long-term fish and invertebrate abundance time series to better understand the dynamical processes regulating marine communities in the Northeast Atlantic and Mediterranean Sea.
How do machine learning models deal with inter-catchment groundwater flows?
Authors: Weaver Nicolas , El-Ouahabi Taha-Abderrahman , Hallouin Thibault , Bourgin François , Perrin Charles , Andréassian Vazken
Published: February 2023

Machine learning models have recently gained popularity in hydrological modelling at the catchment scale, fuelled by the increasing availability of large-sample data sets and the increasing accessibility of deep learning frameworks, computing environments, and open-source tools. In particular, several large-sample studies at daily and monthly time scales across the globe showed successful applications of the LSTM architecture as a regional model learning of the hydrological behaviour at the catchment scale. Yet, a deeper understanding of how machine learning models close the water balance and how they deal with inter-catchment groundwater flows is needed to move towards better process understanding. We investigate the performance and behaviour of the LSTM architecture at a monthly time step on a large sample French data set coined CHAMEAU – following the CAMELS initiative. To provide additional information to the learning step of the LSTM, we use the parameter sets and fluxes from the conceptual GR2M model that has a dedicated formulation to deal with inter-catchment groundwater flows. We see this study as a contribution towards the development of hybrid hydrological models.
Swish floats- an inexpensive neutrally buoyant float to monitor dispersion in coastal seas
Authors: Stevens Samuel , Pawlowicz Rich
Published: February 2023

The direct measurement of subsurface ocean currents using neutrally buoyant free-floating instruments (or “floats”) has been used for decades by oceanographers. These observations are still useful to observe mean flows via repeated Lagrangian measurements, particularly in coastal regions where circulation schemes remain unresolved. To increase the statistical significance of these observations, it is desirable to maximize the number of measurements and therefore minimize the expense associated with collecting these measurements: with this in mind, many inexpensive observations of ocean flows can be preferable to fewer data-rich observations from more expensive platforms. In this talk, I will describe a simple neutrally buoyant GPS float that has been developed at a cost of €200 per unit to measure subsurface dispersion on timescales up to a month. The floats share some passing similarities with the original Swallow floats, thus they nicknamed “Swallow-ish”, or Swish floats. I will outline the float design; discuss the principles governing the neutrally buoyant nature of the floats; and present results from several deployments in the coastal seas of Canada, showing how these simple floats are being used track the dispersion of pollutants through coastal systems via measurements of advection, diffusion, and vertical motion.
High coseismic differential stress preserved in the lattice of seismically shocked garnets
Authors: Toffol Giovanni , Pennacchioni Giorgio , Menegon Luca , Camacho Alfredo , Faccenda Manuele , Wallis David , Bestmann Michel
Published: February 2023

The seismogenic environments build up the highest differential stresses on Earth. Differential stress of as much as hundreds of MPa to few GPa is accumulated during the interseismic loading stage and it is abruptly released in a sequence of fast, high-stress events (earthquake rupture tip propagation, frictional fault slip, thermomechanical interactions) determining large-magnitude, local stress changes on and near the fault plane. A major challenge to obtain a quantification of these stresses is represented by their heterogeneity in space and time. However, they can be exceptionally recorded in exhumed fault rocks bearing pseudotachylytes (quenched coseismic frictional melts).Here, for the first time, we provide a measure of the residual elastic stress preserved in the lattice of seismically shocked garnets crosscut by a pseudotachylyte fault vein by means of HR-EBSD (high-angular resolution electron backscattered diffraction). The thin (3 mm-thick) pristine pseudotachylyte was produced during a single seismic event at mid-crustal conditions (ca. 500 MPa, 500 °C) within felsic gneisses in the hanging wall of the Woodroffe Thrust (Musgrave Ranges, central Australia). Centimetric garnets of the host rock are intensely fractured and extremely comminuted close to the pseudotachylyte. A local enrichment in Mn is associated with healing of the cracks close to the pseudotachylyte and with the growth of epitaxial garnet in the cataclastic portions. HR-EBSD maps (ca. 30 x 50 µm2) were acquired in the garnet at increasing distance from the pseudotachylyte and in a cataclastic domain in contact with it. Residual stresses reach up to 5 – 6 GPa in contact with the pseudotachylyte and decrease to a few hundred MPa in less than a millimeter from it. Similar high stresses are recorded also in the clasts of a cataclasite flanking the pseudotachylyte, while newly grown high-Mn garnet surrounding the clasts records lower stresses. High stress domains in the mapped areas, a few micrometers in size, are bounded by straight bands of stress sign inversion that become less regular and more closely spaced towards the pseudotachylyte. Geometrically necessary dislocations (GND) are more abundant close to the pseudotachylyte and are linked with the high-stress domains.Microstructures, stress gradients and magnitudes all suggest that the extreme residual stresses recorded in proximity of the pseudotachylyte belong to the stage of propagation of the earthquake rupture, in agreement with theoretical predictions of the stress fields at the tip of a propagating fracture. The partial preservation of the stress in the strained lattice of the garnet is made possible by the quasi-instantaneous healing of the cracks that produced a load-bearing framework to maintain the elastic strains and by the presence of high GND densities produced during the high-stress – high-strain rate rupture propagation event.
How well in advance can we predict cold spells over France?
Authors: Goutham Naveen , Omrani Hiba , Himych Omar , Plougonven Riwal
Published: February 2023

France is committed to achieving climate neutrality by 2050. In this respect, the heating sector, one of the largest energy-consuming sectors in France, is undergoing rapid electrification. In 2022, electricity contributed to the heating of more than 40% of French dwellings. As a result, the French electricity demand is increasingly becoming thermosensitive. Accordingly, for every 1°C drop in temperature below the threshold (i.e., 15°C) during winter, the electricity demand increases by ~2.4 GW in France. With a notable share of French nuclear reactors reaching their end of service life, several recent episodes of widespread cold spells over France have raised concerns about energy security. Hence, anticipating cold spells well in advance is increasingly becoming important for the smooth operation of the energy sector. In this regard, we assess the predictability of several recent episodes of cold spells on seasonal timescales over France using the seasonal predictions from the European Centre for Medium-Range Weather Forecasts. Additionally, we test a recently developed statistical downscaling methodology in forecasting cold spells over France, using the forecasts of upper-level fields, which are better predicted than the surface fields. On comparing the dynamical and statistical predictions, we show that the statistical predictions, relying upon the information contained in the better-predicted upper-level fields, perform significantly better than the dynamical counterparts in predicting cold spells beyond a month.
A recent assessment of the state of global cloudiness in the satellite-based climate data records
Authors: Devasthale Abhay , Karlsson Karl-Göran
Published: February 2023

 Four decades of satellite-based observations of clouds are now available and there are currently four different global cloud climate data records (CDRs) available providing 35+ years of data from the passive imagers, namely CLARA-A3, ESA Cloud CCI, ISCCP and PATMOS-X. This contribution presents a comprehensive assessment of the latest versions of these four long-term cloud CDRs. Given the fact that clouds cover nearly 70% of our planet and exert strong control on the radiation budget through their effects on radiation, precipitation, circulation and through their susceptibility to aerosols, such a periodic observational assessment of their global state is necessary from the climate perspective. CLARA-A3, PATMOS-X and ISCCP have been improved considerably in the recent years, thanks mainly to improved calibration, better training, algorithm developments, and rigorous validations.This contribution will focus on three main areas:1) Presenting the state-of-the-art global climatologies of cloud properties from the said CDRs, while highlighting the agreements and disagreements among them.2) Evaluating the decadal stability of cloudiness in these CDRs using CALIPSO and MODIS as the references in light of the stringent requirements set by the WMO Global Climate Observing Systems (GCOS).3) Investigating the robust trends in global cloudiness and their commonalities across the CDRs. 