bluuebunny/crossref_metadata_2025 huggingface dataset:
Does prioritizing environmental flows compromise demand satisfaction and hydropower production in the Nagarjuna Sagar reservoir?
Authors: Sunil Akshay , Singh Riddhi , Molakala Manvitha
Published: February 2023

The trade-offs between human water needs and environmental considerations have always been challenging for water resources management and governance. Multi-purpose reservoirs present a particularly challenging decision context where multi-sectoral water and energy demands have to be balanced, while also considering the instream water requirements downstream. A systematic framework to evaluate the trade-offs between demand satisfaction, hydropower production, and satisfaction of minimum environmental flows (MEFs) would help reservoir operators better understand the consequences of various operational choices. In this study, we designed two formulations of a multi-purpose reservoir operation problem; one that prioritized MEF (PF_MEF) releases over demand satisfaction and another that did not (PF_nMEF). We identified Pareto approximate strategies to operate the reservoir for each formulation using the Borg multi-objective evolutionary algorithm considering multiple objectives related to water demand satisfaction, hydropower production, prevention of flood exceedance thresholds, and satisfaction of MEF. We applied the framework to the Nagarjuna Sagar (NS) reservoir in southern India. Reservoir operation strategies were modeled using direct policy search (DPS), where piecewise nonlinear Gaussian radial basis functions (RBFs) are used to condition decisions, and reservoir releases for hydropower in this case, on reservoir storage states. Results show that the Pareto approximate strategies resulting from optimizing for PF_MEF and PF_nMEF attain MEF - MEF in ranges 86-98% and 56- 79%, respectively. However, the ensuing compromises in water demand satisfaction and hydropower production are not considerably higher. Mean volumetric demand deficits and mean annual hydropower production ranged from 99.9 -818.1 Mm3 (48.13-818.8 Mm3) and 3252-3900 Gwh (3394- 3910 Gwh) for PF_MEF (PF_nMEF). Notably, we were able to identify strategies from PF_MEF that attained low values of volumetric demand deficits and high values of hydropower production, indicating that prioritizing MEFs may not necessarily yield compromises for human-related objectives in this case.
Lithosphere deflection on a juvenile oceanic detachment during seafloor spreading promoted the exposure of the mantle rocks of the Troodos ophiolite – inferences from gabbro paleomagnetism
Authors: Abelson Meir , Kamahaji Lior , Shaar Ron , Agnon Amotz
Published: February 2023

The domal structure in the core of the Troodos ophiolite exposes lower crustal (gabbro suite) and mantle rocks (ultramafic province). This structure is part of a fossil ridge-transform intersection (RTI), where an extinct spreading axis meets the fossil oceanic transform, namely the Arakapas transform. A major feature in the RTI system is the Troodos Forest-Amiandos Fault (TAF), an off-axis and axis parallel fault that was active during the Cretaceous seafloor spreading. Here we investigate the deformation across the TAF by measuring paleomagnetic vectors from 34 sites in the gabbro suite around the domal ultramafic core. Special emphasize was along an E-W transect that crosses the TAF south of the sheeted dike complex and north of the ultramafic province. We also compiled dike dips along an E-W strip (6 km wide) north of the gabbro suite. All results were compared to previous paleomagnetic studies from the sheeted dikes and the gabbro suite. Accordingly, we have found that rotations in the gabbro are very similar to those in the sheeted dikes, suggesting coupling of the upper and the lower oceanic crust during axial deformation of seafloor spreading. All rotation axes were horizontal and parallel to the dike strikes, i.e., parallel to the extinct spreading axis. Rotations increase gradually towards the TAF from both sides, eastward in the footwall and westward in the hanging wall. The most plausible scenario is an upward and downward deflection in the footwall and the hanging wall, respectively, similarly described theoretically for the early stages of detachment development. The orientations of the rotation axes of all paleomagnetic vectors indicate spreading-related deformation. This suggests that the relative uplift of the deep-seated rocks was by the development of a young detachment during seafloor spreading rather than serpentinite diapirism. The detachment occurrence in the outside-corner is explained here by the shift from orthogonal to curved axis, inferred from sheeted dike orientations.
Extremes of meridional energy transports in Northern Hemisphere mid-latitudes across zonal wavenumbers and dominant weather regimes
Authors: Lembo Valerio , Fabiano Federico , Galfi Vera Melinda , Graversen Rune Grand , Lucarini Valerio , Messori Gabriele
Published: February 2023

Extremes in extratropical meridional energy transports in the atmosphere are associated with the dynamics of the atmosphere at multiple spatial scales, from planetary to synoptic. This is related to the nature of amplifying baroclinic waves, that are fundamentally intermittent and sporadic, significantly affecting the net seasonal transport across latitudes. Here, we use the ERA5 reanalysis data to perform a wavenumber decomposition of meridional energy transports in the Northern Hemisphere mid-latitudes during winter and summer. Extreme transport events are linked to atmospheric circulation anomalies and dominant weather regimes, identified by clustering 500 hPa geopotential height fields. Partitioning the extreme events across zonal wavenumber highlights the different role of scales in different seasons and regions. In general, planetary-scale waves determine the strength and meridional position of the synoptic-scale baroclinic activity with their phase and amplitude. During winter, large wavenumbers (k = 2–3) are key drivers of the meridional-energy-transport extremes, and planetary- and synoptic-scale transport extremes virtually never co-occur. In summer, extremes are associated with higher wavenumbers (k = 4–6), identified as synoptic-scale motions. Focusing on recently occurred exceptionally strong summertime heat waves and wintertime cold spells, we notice that regime structures of these events are typical of extremely large poleward meridional energy transports.
Improving methods to calculate the monthly water budget for Lake Velence, Hungary
Authors: Chappon Máté , Bene Katalin
Published: February 2023

In recent years the water levels of Lake Velence - Hungary's third-largest lake - have dropped significantly due to a series of climatic and anthropogenic phenomena. Water managers calculate the lake's water budget based on a methodology established almost 50 years ago. The calculation error is determined as the difference between the computed and observed lake levels. A previous study on the calculation errors of annual water budget computations has found several uncertainties that result in predominantly negative errors; underestimating inflows and, or overestimating outflows.This study focuses on monthly water budget computations to investigate the possible causes of the calculation errors. The monthly error distribution shows that negative calculation errors accumulate during the year's first five months. Based on this outcome, the methods for determining monthly precipitation, evapotranspiration and surface inflow are explored in more detail for the January – May period. Remote sensing data and numerical modelling were used to fill spatial and temporal data gaps.The research will result in an improved water budget calculation method, which enhances our understanding of the main processes governing lake water levels. The new approach will give water managers a clearer picture of the effectiveness and necessity of engineering interventions to restore lake water levels.The research is carried out within the framework of the Széchenyi Plan Plus program with the support of the RRF 2.3.1 21 2022. 00008 project. 
Analysis of dissolved nitrate stable isotopes using the one-step Ti (III) reduction method and Elementar EnvirovisION System
Authors: Barker Sam , Preece Calum , Berstan Rob , Seed Mike
Published: February 2023

Identifying and quantifying sources and cycling of nitrogen is important for understanding not only aquatic ecosystems but also planning water resource management, mitigating urban and agricultural pollution, and optimizing government policy. Stable isotopes of dissolved nitrate and nitrite (δ15N, δ18O and δ17O) have been useful in distinguishing between the diverse nitrogen sources and sinks and help understand large scale global ocean processes as well as revealing major changes in agricultural land use and urbanization. 

Despite the strength of dissolved nitrate and nitrite stable isotope analysis, the strong barrier for uptake using the favored contemporary methods (bacterial denitrifier and Cd-azide reaction) due to the laborious multi-step methods, maintenance of anerobic bacterial cultures and use of highly toxic chemicals has limited the analysis to highly specialized laboratories. We evaluate the performance of the Elementar EnvirovisION using the new Titanium (III) reduction method (Altabet et al., 2019) for one step conversion of nitrate into N2O for IRMS analysis.   

The EnvirovisION has been developed for high performance analysis of CO2, N2O and CH4 and dissolved nitrate. The system has the capacity to be rapidly customized for specific needs with options for dual GC columns supporting the Weigand ‘heart-cut’ N2O method (Weigand et al., 2016) and sequential N2 and N2O analysis from a single atmospheric sample. 
Can India leapfrog into a clean air future – perspectives from measurements, source-receptor modelling and emission inventories
Authors: Sinha Baerbel , Hakkim Haseeb , Sharma Gaurav , Chaudhary Pooja , Kumar Ashish , Pawar Harshita , Chandra Praphulla B. , Sinha Vinayak
Published: February 2023

India struggles with frequent exceedances of the ambient air quality standard for particulate matter, ozone and benzene. The situation in the Indo-Gangetic plain (IGP) is particularly severe during post monsoon and winter season.We show that despite strong governmental efforts to make clean energy accessible and affordable, residential solid fuel usage is still the largest source of particulate matter pollution and carcinogenic benzene in India. Particularly cow dung as a cooking and heating fuel contributes disproportionally to the residential sector emissions and India’s air quality challenge. In addition, crop residue burning, open burning of waste, solid fuel usage in industrial boilers, and power generation units also contribute significantly to the particulate matter and benzene emissions over the region. In urban agglomerations, transport sector emissions aggravate the already poor air quality further.In this talk we present several recently updated gridded emission inventories with detailed VOC speciation for these air pollution sources. We also look at future projection under different Shared Socioeconomic Pathways (SSPs) for several sources.We focus on the most polluted part of the year, namely post-monsoon and winter season, to evaluate and compare these updated emission inventories against other available emission inventories and measurements studies. We find that that existing inventories tend to underestimate the magnitude of residential sector emissions and their strong seasonality. The use of solid fuels for heating purposes results in a strong temperature induced emission feedback that can aggravate the wintertime fog. Existing inventories also underestimate the magnitude of crop residue burning emissions and lack open waste burning as a source.A combination of measurement-based assessments and emission inventories for different air quality intervention strategies are used to evaluate a number of possible air quality interventions for their potential impact. We specifically look at the sectoral coupling between the residential sector, waste management, crop residue management, and the transport sector to propose interventions that maximize air quality gains.
Dakar Niño variability under global warming investigated by a high-resolution regional coupled model
Authors: Koseki Shunya , Vazquez Ruben , Cabos William , Guitérrez Claudia , Sein Dmitry
Published: February 2023

We have investigated an interannual variability of sea surface temperature (SST) along the northwestern African coast, so-called, Dakar Niño, and its change under global warming of highest emission scenario RCP8.5 employing a high-resolution regional coupled model. Our reginal coupled model is capable of reproducing the seasonal cycle of the SST along the northwestern African coast and its interannual variability with respect to amplitude, timing, and position of the maximized variability between 9°N-14°N from March to April. Comparing the Dakar Niño variability between the periods of 1980-2010 and 2069-2099, we found that its variability intensifies under warmer climate without changing its location and timing of maximization. The intensification is more pronounced during the Dakar Niñas (cold SST event) than during Niños (warm SST event) and the variability in ocean temperature is connected more deeply with the Dakar Niño variability (vertical motion is more strongly correlated). The stronger Dakar Niño variability and deeper connection with subsurface variability can be explained by the larger meridional wind stress variability along the northwestern African coast, which can be amplified by more enhanced land-sea thermal contrast anomaly, in the future. In addition, the ocean temperature is warmed more effectively above 40m depth where the temperature anomaly is more dominant, that is, the stratification is reinforced around 40m depth. This enhanced stratification can also cause the reinforcement of Dakar Niño/Niña variability.     
Variability of Warming at Mixed Layer Base in the Subtropical South Indian Ocean Salinity Maxima Region
Authors: Kaundal Madhu , Nadimpalli Jithendra Raju , Dash Mihir Kumar
Published: February 2023

Subtropical South Indian Ocean salinity maxima region plays an important role in transporting temperature anomalies towards north along the isopycnals following geostrophic pathways. In this study, interannual and decadal changes in temperature and salinity at the base of mixed layer during austral winters are investigated for the Argo era. Winter time deep mixed layer allows these Temperature/Salinity (T/S) changes to penetrate to the permanent pycnocline. Interannual changes in the mixed layer depth (MLD) are mostly driven by convective buoyancy and wind forcing. Contribution of different atmospheric and oceanic forcing to the changes in mixed layer temperature and salinity are shown using mixed layer budget calculation. It is observed that net heat flux term dominates the temperature changes whereas meridional advection plays a important role in driving salinity changes in the mixed layer. Mixed layer T/S changes are subducted to the permanent pycnocline mainly by lateral induction process because of large meridional MLD gradient. Density compensated anomalies also contribute to the T/S changes at the bottom of the mixed layer. Interannual temperature anomalies due to spiciness and heaving are further explored.
Towards a harmonized data ecosystem in Earth and Environment– a view on the Helmholtz Association’s Data Infrastructures
Authors: Soeding Emanuel , Poersch Andrea , Weinelt Martin , Buttigieg Pier Luigi , Kollai Helen , Lorenz Sören , Razeghi Yousef
Published: February 2023

The interconnectivity of existing data infrastructures (DIS) across national and international initiatives (e.g. NFDI, EOSC and others) is an important goal to create a common interoperable data ecosystem. To achieve this, it is critical to harmonize the existing methods and concepts of research data collection, research data-reuse, among the DIS and along the FAIR principles.Within the Helmholtz Association we maintain more than 50 data infrastructures in the field of Earth and Environment. Procedures of data handling, documentation and storage are hardly coordinated within Helmholtz, even less so within the larger community. To find out about the state of our infrastructures, the different approaches in data management procedures, technical capabilities, and concepts, we conducted a survey among all Helmholtz DIS. We asked questions related to their roles in the community, self-perception, quality control, curation, technology interfaces, data re-use and demands.Based on this data we developed our vision to create a “Helmholtz data space”, unifying Earth and Environmental Centres and infrastructures and powering a new wave of large-scale, globally oriented, data driven research. The Helmholtz Metadata Collaboration’s (HMC) mission is, to federate (meta)data systems across Earth and Environment Centres and infrastructures throughout the Helmholtz Association, continuously aligning Helmholtz capacities to global norms and developments.
Decoupling thermo-hydraulic processes from chemical reactions to understand the effect of heat on chemical reactions
Authors: Vidal Rubén , Saaltink Maarten W.
Published: February 2023

Changes in temperature can modify the geochemistry of groundwater. This effect is very relevant not only for natural geothermal phenomena, but also for geothermal energy systems and Underground Thermal Energy Storage (UTES) systems. We propose a novel method that can be used to verify sophisticated numerical models and understand the thermo-hydro-chemical (THC) processes more clearly. The method decouples the chemistry from the thermo-hydraulic (TH) processes. The chemistry is obtained from geochemical batch calculation by PHREEQC and the TH processes from the finite element code CODE_BRIGHT. The method has been applied to a UTES pilot project near Bern, Switzerland, and compared with the THC coupled code RETRASO. The good agreement between the presented method and RETRASO verifies the correct implementation of our method. Moreover, the results provide information about the dominant reactive transport processes, mineral reaction rates and porosity changes.Acknowledgements: This work was financed by the ERANET project HEATSTORE (170153-4401). This project has been subsidized through the ERANET cofund GEOTHERMICA (Project n. 731117), from the European Commission, RVO (the Netherlands), DETEC (Switzerland), FZJ-PTJ (Germany), ADEME (France), EUDP (Denmark), Rannis (Iceland), VEA (Belgium), FRCT (Portugal), and MINECO (Spain). Also, the first author is supported by a grant from the Department of Research and Universities of the Generalitat de Catalunya (2022 FI_B1 00208).
Modelling mass balance and stress transfer at Krafla and Theistareykir geothermal systems, Iceland
Authors: Giuliante Beatrice , Jousset Philippe , Krawczyk Charlotte , Hinderer Jacques , Riccardi Umberto , Toledo Tania , Forster Florian , Mortensen Anette
Published: February 2023

The sustainable exploitation of a geothermal reservoir is usually assessed through continuous field monitoring and structural exploration of the hydrothermal reservoir. However, accurate subsurface mass and fluid displacement as well as energy transfer model of the hydrothermal reservoir is most of the time not resolved enough both in space and time. Since 2017, both at Krafla and Theistareykir powerplants (northern Iceland), we use several multi-parameter stations each equipped with a gravity meter (superconducting or spring relative meter), a broad band seismometer, a GNSS receiver and other meteorological and hydrological sensors. With this set-up, we aim to model mass and stress transfer through the combination of absolute and micro gravity measurements, continuous signals measured at the multi-parameter stations and seismic measurements.We present results from the 2022 micro gravity and absolute gravity campaigns conducted at Theistareykir geothermal field. Through inversion and interpretation of such results, as well as the analysis of the continuous measurements, and injection and production data, we aim to assess the anthropogenic contribution in the mass and energy transfer models of the investigated area.  Furthermore, we show the first continuous measurements and accurate Earth tide model for the Krafla area. The final goal of this study is to verify the conditions of sustainable exploitation of the reservoirs, and establish reservoir parameters, such as permeability, that regulate the response of the geothermal system to changes in production and injection rates.
Towards large-scale compound flood risk modeling
Authors: Eilander Dirk , Couasnon Anaïs , Sperna Weilander Frederiek , Winsemius Hessel , Ward Philip
Published: February 2023

In low-lying coastal areas floods occur from (combinations of) fluvial, pluvial, and coastal drivers. If these drivers co-occur, they can cause or exacerbate flooding, and are referred to as compound flood events. Furthermore, if these flood drivers are statistically dependent, their joint likelihood might be misrepresented if dependence is not accounted for. However, most large-scale flood risk models do not account for the hydrodynamic interactions and statistical dependence between flood drivers. We present a globally-applicable framework for compound flood risk assessments using combined hydrodynamic, impact and statistical modeling. The framework broadly consists of three steps. First, a large stochastic event set is derived from reanalysis data, taking into account co-occurrence of, and dependence between all annual maxima flood drivers. Then, both flood hazard and impact are simulated for different combinations of drivers at non-flood and flood conditions. Finally, the impact of each stochastic event is interpolated from the simulated events to derive a complete flood risk profile. The framework has been applied to a case study in Mozambique where we found that if dependence between flood drivers is not accounted for, the impact of especially rare events is underestimated. In this contribution we discuss findings from the case study as well as challenges faced when upscaling the framework to for large-scale compound flood risk assessments.
Optimal sampling resolution for water isotope records in ice cores
Authors: Shaw Fyntan , Dolman Andrew , Kunz Torben , Gkinis Vasileios , Laepple Thomas
Published: February 2023

Water isotopes in ice cores offer a window into the climate of the past. Often the measurement of these water isotopes is done discretely, with the ice cores cut into many regularly spaced samples. Determining the optimal sampling rate for these measurements is a question of balancing high temporal resolution with processing time and effort. Furthermore, the effect of isotopic diffusion smooths the record, attenuating high frequency variability far below the measurement noise level. This results in some climate information becoming unobtainable and limits the usefulness of very high resolution data. Deconvolving (un-diffusing) the time-series can further enhance the signal but strongly depends on the precision of the isotope data that is mainly determined by the measurement error.Here, we discuss the optimal measurement specifications in terms of sampling resolution and precision for different uses of the water isotope data, such as the estimation of the diffusion length, the direct interpretation of the time-series and the interpretation of the time-series after it has been deconvolved. We do this theoretically, based on how we model diffusion, and empirically through simulations of surrogate ice core records. Our findings can provide guidance on how to process new deep ice cores such as the Oldest Ice Core record.
Salt-influenced fold-and-thrust belts: insights from experimental analog models
Authors: Santolaria Pablo , Granado Pablo , Muñoz Josep Anton , Ferrer Oriol , Wilson Elizabeth P. , De Matteis Marco , Snidero Marco , Gratacós Oscar , Roca Eduard
Published: February 2023

In this work, we experimentally explore the role played by salt in contractional systems: from simple layer-cake, salt-floored settings to inverted salt-bearing rifted-margins, the inherent low-strength rheology of salt and its distribution determine particular structural styles and kinematics. Salt-detached contractional systems exhibit low taper angles, with no dominant structural vergence, and are comparatively wider in cross section than their non-salt-involved equivalents. The salt-sediment thickness controls structural spacing while the presence of pre-existing isolated salt bodies breaks the mechanical homogeneity. If salt bodies are connected through a framework of salt walls, contractional deformation concentrates in them and structural trends are no longer perpendicular to shortening but determined by the inherited orientation of salt bodies.Finally, we assess the inversion of a salt-bearing rifted margin, where late syn-rift to early post-rift salt undergoes differential loading and gravity gliding leading to a salt-sediment architecture consisting of a salt wall-minibasin province, and a distal raft system. Upon shortening, inherited salt bodies localize contractional deformation and the salt-sediment architecture determines the structural configuration of the contractional system. In the experiments, a large-transport thrust detached along allochthonous salt accumulated in the distal raft system, and the squeezing of salt walls together with the tilting of minibasins, accounted for most of the shortening in the salt wall-minibasin province. During shortening, about 75% of the original salt evacuates and is eroded. Due to the low salt-sediment ratio found in fold-and-thrust belts, the role played by salt tectonics could be underestimated. So, the best practice approach for understanding structural style and kinematics of salt-influenced fold-and-thrust belt resides in the rifted margin stratigraphy involved, and not in the salt itself, since salt is generally poorly preserved and strongly deformed.
Why atmospheric methane surged in 2020?
Authors: Peng Shushi , Lin Xin , Thompson Rona , Xi Yi , Liu Gang , Lan Xin , Hauglustaine Didier , Poulter Benjamin , Ramonet Michel , Saumois Marielle , Yin Yi , Zhang Zhen , Zheng Bo , Ciais Philippe
Published: February 2023

Methane (CH4) levels in the atmosphere increased by 15.1 ± 0.4 ppb in 2020, the highest annual increase from 1984 to 2020, despite a likely decrease in anthropogenic CH4 emissions during COVID-19 confinements. Here, we used bottom-up and top-down methods to quantify the changes in different sources of CH4, and in its atmospheric sink due to the hydroxyl radical (OH) in 2020 compared to 2019. Bottom-up methods showed that, globally, total anthropogenic emissions slightly decreased by ~1.2 Tg CH4 yr-1, fire emissions were lower than in 2019 by ~6.5 Tg CH4 yr-1, and wetland emissions increased by 6.0 ± 2.3 Tg CH4 yr-1. In addition to higher wetland emissions in 2020 than 2019 from bottom-up, we found a decrease of 1.6–1.8% in tropospheric OH concentration relative to 2019, mainly due to lower anthropogenic NOx emissions and associated lower free tropospheric ozone during the confinements. Based on atmospheric CH4 observations from the surface network, and considering the decrease in OH, using top-down inversions, we infer that global net emissions increased by 6.9 ± 2.1 Tg CH4 yr-1 in 2020 relative to 2019, while the global CH4 removal from reaction with OH in the atmosphere decreased in 2020 by 7.5 ± 0.8 Tg CH4 yr-1. Therefore, we attribute the positive growth rate anomaly of atmospheric CH4 in 2020 relative to 2019 to lower OH sink (53 ± 10%) and higher natural emissions (47 ± 16%), mostly from wetlands. Warmer and wetter climate conditions in the Northern Hemisphere promoted wetland emissions, but fires decreased in the Southern Hemisphere, compared to the previous year. Our study highlights that northern microbial emissions of CH4 are highly sensitive to a warmer and wetter climate and could act as a positive feedback in the future. Our study also hints that the global CH4 pledge must be implemented by taking into account NOx emissions trend, whose reduction lengthens the lifetime of atmospheric CH4.
Understanding dynamics of ground movement based on seismic monitoring
Authors: rawat Deepak , sharma Mukat lal
Published: February 2023

Given the unique geology, topography, and hydrology of the Himalayas, it is imperative that a long-term strategy be developed to reduce the destructive potential of landslides in the region. Monitoring and an early warning system for landslides are the best non-structural measures for preventing landslide disasters. The study's overarching objective is to highlight why it's crucial to keep an eye out for landslides and how seismic sensor arrays can be used to issue early warnings. The implications of large mass flows in the study area must be carefully considered for sustainable hydropower and other socio-economic development projects. Seismic data, satellite imagery data, Time-Frequency analysis (TFA), and videos and photos taken by eyewitnesses form the basis of our investigation.First, we gather precise event data, and then we collect signals from the seismology observatory at the Indian Institute of Technology Roorkee for that time frame. The signals from the collection have been processed with signal processing methods like STA/LTA, Filtering, and TFA. One synthetic signal, two landslide events, and two local earthquakes were analyzed to better comprehend the dynamics and behavior of a natural distractive event.Seismic records reveal that various types of events have distinctive dynamic properties. There are three distinct stages to a landslide event: (1) the detachment of slope-forming materials, (2) the debris flow, and (3) the flood flow. The P and S waves, the onset and end times, and the duration of an earthquake have all been determined. We have used synthetic signals to learn about TFA and have found the method that works best for interpreting seismic signals. We use the classification method developed by Provost et al. in 2017. Time-domain amplitude levels are a feature that can be easily extracted and classified, but they are also vulnerable to noise. Energy concentration in the time-frequency domain is one such method that, while requiring more complex operations, can lead to more trustworthy feature extraction and accurate classification. The absence of the distinct P- and S-wave arrival time, as is typical of earthquakes, is another feature of the seismic waveform that is indicative of a landslide. The results of the seismic record analysis also shed light on the breadth of monitoring for slope-moving disaster events in the North-West Himalayas.
Experimental investigation of the segregation of a large intruder in bedload sediment transport
Authors: Dedieu Benjamin , Frey Philippe , Chauchat Julien
Published: February 2023

Vertical size segregation or sorting of particles in bedload transport, strongly impacts the sediment rate and the river bed morphology. To better account for this process in sediment transport models, it is essential to understand the mechanisms acting at the grain scale (Frey, 2009). Following the work of Rousseau (2021), focus is made on the behaviour of a single large particle segregating upwards in a monodisperse mixture of smaller beads during bedload transport. Experiments are carried out in a narrow flume and the bead dynamics is recovered through image analysis. A great number of repetition is performed for different size ratios (large to small bead diameter) in order to conduct statistical analysis. This work confirms the measurements from Rousseau (2021) and suggests that the time for the large particle to reach the bed surface is minimum for a size ratio of 2. This result supports previous research which, using simpler granular configurations, evidenced a similar tendency in terms of segregation force (Guillard, 2016, Jing, 2020) or segregation velocity (Golick, 2009). Other observations are made on the spatial trajectory of the intruder, which have been previously reported to be linear with a repeatable slope independent of the size ratio. These observations offer interesting insights to understand the mechanisms governing size segregation and could provide new closures to upscale the phenomenon at the continum scale.Illustration: A 5 mm intruder in a 2 mm bed (size ratio = 2.5), flow from right to left, dimensionless bed shear stress (Shields number) = 0.25.Frey, P. and Church, M. (2009). “How River Beds Move”. Science, 325(5947), pp. 1509–1510.Golick, L. A. and Daniels, K. E. (2009). “Mixing and Segregation Rates in Sheared Granular Materials”. Physical Review E, 80(4), p. 042301.Guillard, F., Forterre, Y., and Pouliquen, O. (2016). “Scaling Laws for Segregation Forces in Dense Sheared Granular Flows”. Journal of Fluid Mechanics, 807.Jing, L., Ottino, J. M., Lueptow, R. M., and Umbanhowar, P. B. (2020). “Rising and Sinking Intruders in Dense Granular Flows”. Physical Review Research, 2(2), p. 022069.Rousseau, H. (2021). “From Particle Scale to Continuum Modeling of Size Segregation in Bedload Transport : A Theoretical and Experimental Study.” PhD thesis. Université Grenoble Alpes.Rousseau, H., Frey, P., and Chauchat, J. (2022). “Experiments on a single large particle segregating in bedload transport”. Physical Review Fluids, 7(6), p. 064305.
Frictional melting and thermal pressurization during seismic slip controlled by drainage
Authors: Wu Wen-Jie , Kuo Li-Wei , Kuo Chia-Wei , Wu Wei-Hsin , Sheu Hwo‐Shuenn
Published: February 2023

frictional melting and thermal pressurization are commonly proposed to reduce dynamic shear resistance along a fault during earthquake propagation. The key factor on triggering either thermal pressurization or frictional melting may be the hydraulic properties of surrounding rock. Observations in Taiwan Chelungpu-fault drilling project (TCDP) Hole-A and Hole-B suggest that frictional melting and thermal pressurization occurred along the fault during the Mw 7.6 Chi-Chi earthquake, but the underlying process is still unclear. Here, we present the microstructural observation in experimental and natural fault gouge, the mechanical data at seismic rate and mineralogical characteristics. Results show that amorphous material only occurred at drained condition. Taken together, these results imply that the difference between Hole-A and Hole-B is attributed to the drainage.
Ion heat flux associated with the Kelvin-Helmholtz instability in a non-uniform plasma: Numerical hybrid-Vlasov results
Authors: Tarvus Vertti , Turc Lucile , Zhou Hongyang , Cozzani Giulia , Ganse Urs , Pfau-Kempf Yann , Alho Markku , Battarbee Markus , Dubart Maxime , George Harriet , Horaites Konstantinos , Suni Jonas , Tesema Fasil , Zaitsev Ivan , Palmroth Minna
Published: February 2023

The presence of a velocity shear layer in a plasma can lead to the development of the Kelvin-Helmholtz instability (KHI). KHI is characterised by the growth of waves that roll up to form non-linear vortices. An example of such velocity shear layer is found at either flank of Earth's magnetopause, where KHI acts a driver of mass and energy transfer from the solar wind into the magnetosphere. Within the rolled-up vortices, kinetic length scales may be attained, allowing vortex-induced magnetic reconnection and kinetic-scale diffusion to operate. In the present study, we have considered the realistic case of a density/temperature jump across the magnetopause and modelled the development of the KHI using a local hybrid-Vlasov simulation with the Vlasiator code. For a case with a northward directed magnetic field, we find that an enhanced ion heat flux arises at vortex boundaries whose thickness approaches the ion gyroscale. Furthermore, the direction of the heat flux vector closely follows the direction of the vortex boundary tangent vector. As such, this signature could provide observational evidence of ion diffusion occurring within KHI, and also information on vortex boundary geometry with single spacecraft data. To validate our results, we compare our simulation run with data from the Magnetospheric Multiscale Mission.
Molecular Dynamics Studies of Halogen Bonding on the Freezing in Clouds
Authors: Yerby Cooper J. , Bertho Gabriel G. , Zhu Chongqin , Francisco Joseph S.
Published: February 2023

The retention coefficients for halogen gases upon freezing of water are currently not estimated. Estimating their retention coefficients is an important metric, enabling atmospheric chemists and modelers to better approximate the respective influences and lifetimes of trace gasses in the atmosphere. Using molecular dynamic simulations that simulate the freezing of cloud water droplets containing halogen gasses in the upper troposphere (220°K), we have revealed that Cl2, Br2, and I2 are entirely retained when water droplets are frozen during deep convection. The results of the simulations show that the presence of halogen gasses in cloud droplets retards their freezing rates by approximately 35% to 62%.  Enumeration of hydrogen and halogen bonds formed between gas species and water in cloud droplets shows that substantially more halogen bonding than hydrogen bonding occurs among halogen gasses. Additionally, data indicates the size of halogen species within cloud droplets may affect their freezing rates. Our results provide a theoretical framework to make the first estimates regarding halogen gas retention coefficients, helping to elucidate impacts halogens may have on the gas transportation dynamics and chemistries of the upper troposphere and lower stratosphere (UTLS). As halogen gas emissions continue to increase globally, this study calls upon the emergent need to assess the role of halogen gasses in UTLS chemistry, especially in the deep convective regions.
Constraining the overall future projection of Upernavik Isstrøm by observations
Authors: Jager Eliot , Gillet-Chaulet Fabien , Champollion Nicolas , Millan Romain
Published: February 2023

The uncertainty of the future contribution to sea level rise of the Antarctic and Greenland polar ice sheet remains important, as shown by the latest multi-model intercomparison (ISMIP6). We can summarise three main sources of uncertainties that are related to the ice flow model, the atmospheric and oceanic forcing and final to the Shared Socioeconomic Pathways (SSP). Results for the Greenland Ice Sheet (Goelzer and al., 2020) show that the model uncertainty explains a similar part of the ensemble spread (40 mm of sea-level rise by 2100) compared to the atmospheric forcing uncertainty (36 mm) or the SSP uncertainty (48 mm) and two times more than the ensemble spread due to the oceanic forcing uncertainty (19 mm). Uncertainties in ice flow models are mainly due to different assumptions in numerical models and parameterisation, as well as model initialisation (spin-up, data assimilation). Here, we investigate the sensitivity of a single ice flow model (Elmer/Ice) to different sources of uncertainties for Upernavik Isstrøm, a tidewater glacier in the North-West sector of Greenland. To achieve this goal, we have identified potential sources of uncertainties: parameters related to the initialization of the model by inverse method (ice stiffness, friction law, regularization, input observations), those related to the dynamics (ice flow law, friction law) and finally those related to the forcing (sensitivity to the ocean, global climate model, regional climate model, SSP). To evaluate their influence we run a 200-member ensemble that samples these different sources of uncertainty. Each member is initialised to a state close to 1985 and evaluated during a historical simulation from 1985 to 2015 where the front positions are forced using observations (Wood et al., 2021). We then use the ISMIP6 protocol where the front position is parametrized as a function of ocean temperature and runoff to perform projections to 2100.We then evaluate the sensitivity of this ensemble to our different sources of uncertainty using Sobol indices. Based on this novel approach, we define several metrics that allow us to score individual ensemble members using a comprehensive record of ice velocity, surface elevation and mass loss over the period 1985-2015. We then evaluate the possibility of reducing the uncertainty in Upernavik Isstrøm's contribution to sea level rise using these scores. 
Spatio-Temporal Datacube Infrastructures as a Basis for Targeted Data Spaces
Authors: Baumann Peter
Published: February 2023

Data Spaces promise an innovative packaging of data and services into targeted one-stop shops of insight. A key ingredient for the fulfilment of the Data Space promise is easier, analysis-ready and fit-for-purpose access in particular to the Big Data which EO pixels and voxels constitute. Datacubes have proven to offer suitable service concepts and today are considered an acknowledge cornerstone. In the GAIA-X EO Expert Group, a subgroup of the Geoinformation Working Group, one of the use cases investigated is the EarthServer federation. It bridges a seeming contradiction: a decentralized approach of independent data providers - with heterogeneous offerings, paid as well as free - versus a single, common pool of datacubes where users do not need to know where data sit inorder to access, analyse, mix, and match them. Currently, a total of 140+ Petabyte is online available. Membership in EarthServer is open and free, with a Charter being finalized ensuring transparent and democratic governance (one data provider - one vote). EarthServer thereby presents a key building block for the forthcoming Data Spaces: not only does it allow unifying data within a given Data Space, it also acts as a natural enabler for bridging and integrating different Data Spaces. This is amplified by the fact that the technology underlying EarthServer is both the OGC datacube reference implementation and the INSPIRE Good Practice. In our talk we present concept and practice of location-transparent datacube federations, exemplified by EarthServer, and its opportunities for future-directed Data Spaces.
Human activities : main drivers of the erosion in the northern French Alps over the last 3800 years
Authors: Rapuc William , Giguet-Covex Charline , Bouchez Julien , Genuite Kim , Jacq Kévin , Sabatier Pierre , Messager Erwan , Poulenard Jérôme , Gaillardet Jérôme , Arnaud Fabien
Published: February 2023

Land is the principal support for human livelihoods as it supplies food, freshwater and multiple other ecosystem services. In the current context of global anthropization and climate change, soil erosion is becoming a threat for human societies and one of the question that most deserve the attention of the entire world & scientific community. Given the large uncertainties underlying the drivers of land erosion, it is crucial to assess the impact of human activities and climate fluctuations over erosion, especially in mountain areas, where erosion is the highest. Only studies combining large spatial and temporal approaches allow to assess the effect of the different forcing factors on soil erosion rates. Here, we apply a retrospective approach based on lake sediments to reconstruct the long-term evolution of erosion in alpine landscapes. Lake Bourget, located in the northern French, acts as a natural sink for a fraction of the erosion products from its large catchment. We combined a multiproxy study of lacustrine sediment sections covering the Holocene with a source-to-sink method, using isotopic geochemistry (εNd). The applied methodology allows us to disentangle the role of climate and land use as erosion forcing factors through their differential impact on the various rock types present in the catchment. Indeed, high-altitude areas of the study site, where the erosion is dominated by precipitation and glacier advances, present isotopic signature different from those of the sedimentary rocks located in the rest of the catchment, where both human activities and precipitations impact erosion through time. To understand the effect of human activities, erosion signals from high-altitude and the rest of the catchment were compared to local and regional indexes of human activities, obtained from pollen and environmental DNA studies conducted on lake sediment sequences. For the last 3.8 kyr, climate fluctuations alone cannot explain measured erosion trends. Between the Late Bronze Age and the modern times, human activities are at the origin of a two-fold increase of the erosion rates in the Alps. Human activities, by modifying the soil erodibility through land-use (agriculture, grazing, ore extraction and deforestation) is the dominant forcing factor of the physical erosion in mountainous environment of the European Alps at least for the last 3800 years.
What does it mean to be a data researcher and platform facilitator of crowdsourced weather observations?
Authors: Garcia-Marti Irene , Noteboom Jan Willem
Published: February 2023

In 2011 the UK Met Office established the Weather Observations Website (WOW) initiative, a global-coverage project in which users of personal weather stations (PWS) can contribute their weather observations to a central repository. In this decade, more than 10,000 PWS around the world have contributed 2 billion measurements to this project, with a remarkable presence of WOW users in Europe. The Dutch Met Office (KNMI) joined this initiative as partner in 2015. In the past 8 years, 1,000+ PWS located in the Netherlands have collected 250+ million observations of the most relevant weather variables, and the interest of the Dutch public in this network continues growing. 
In this context, the KNMI has two main roles with respect to WOW-NL observations: Platform Facilitator and Data Researcher. The KNMI facilitates WOW-NL to the public via the portal http://wow.knmi.nl, which enables visualizing the latest observations in a map, allows querying to inspect the historical data contributed by each station, and provides a space for news. As platform facilitator, the KNMI aims for a measurement system of PWS that provides optimal added value to our science and services. The Data Research teams at KNMI have dedicated continuous efforts to develop quality controls (QC) enabling a full quality assessment of the WOW-NL observations. The latest results show that the application of QC methods yields promising results for air temperature, rainfall, and wind speed measurements. This means that WOW-NL observations may have sufficient quality to be incorporated into successive research or operational workflows and become part of the ‘daily business’ of the organization. 
These two roles are designed to work independently, but we believe that bringing them together would positively and effectively impact quality of data for the organization’s science and services. Hence, how can we interlace them most optimally in a feedback loop and take them to the next level? How can we expand the Platform Facilitator role, to stimulate and provide guidance for citizens to obtain quality of crowd sourced data most optimal for our science and services? How to enable the Data Researcher role to deliver peer-reviewed scientific content to a broader audience and in a real-world set up? Last but not least, how to establish a dialogue with the users to create a community ensuring long-term data provision for national meteorological services?
In this work we investigate the relationship between the Platform Facilitator and the Data Researcher roles to balance investment in actions “upstream” (e.g. network design, PWS location) vs “downstream” (e.g. metadata, statistical QC procedures). We also elaborate on how the inclusion of WOW-NL in operational workflows might require revisiting or creating new policies for crowdsourced data or assessing the readiness of the digital infrastructure of the organization.