bluuebunny/crossref_metadata_2025 huggingface dataset:
Urban Landscape Change in the Trans-Himalayan Town of Kargil, Ladakh, India
Authors: Hussain Altaf , Schmidt Susanne , Nüsser Marcus
Published: February 2023

Small and medium-sized towns in the high mountain regions of South Asia are characterized by rapid and mostly unplanned urbanisation processes resulting in increased risk to natural hazards, such as flash floods, landslides and earthquakes. Due to rapid urban expansion, the case study of Kargil, the second largest city of the Union Territory of Ladakh is chosen to identify risk-prone areas. Based on multi-temporal approach using high resolution satellite imagery (Corona, ASTER and PlanetScope), statistical data and repeated field surveys, urban landscape changes are analysed since the 1960s. The population of Kargil town increased from 1,681 in 1961 to 16,338 in 2011, while total population of the entire Kargil district multiplied from 45,064 to 140,802 over the same period. The built-up area of Kargil town has grown from 0.25 km² to 2.30 km² between 1965 and 2020. The mountain region of Kargil is particularly vulnerable to natural disasters such as landslides, cloudbursts, and flash floods. The main highways (NH-1D and NH-301) connecting Kargil with adjacent regions are prone to landslides. Recurring flash floods in the surrounding of Kargil town was observed in the years 2006, 2010, 2013, 2014, 2016 and 2018, which caused massive damages to roads, buildings, and agricultural area. Most recent flash floods occurred in Kargil town (Baroo and Titichumik) and in different rural villages of Chiktan, Suru and Drass in 2022. These settlements are either located along the streams or on low lying banks of the main rivers, Suru, Drass and Wakha; examples include hazard prone areas such as the new bus stand, and Kabadi Nallah on the banks of Suru river and several other new settlements like Silmo colony or Andoo colony in Kargil town. Urban expansion does not only cover the most suitable areas but increasingly sprawls across steep slopes; examples include the new residential areas of Silmo colony, Andoo colony, and Haidery Mohalla. These new urban settlements are extremely prone to natural hazards and question the sustainability of town planning in this mountain region. The central old town, Baroo colony and Poyen colony are already saturated due to unplanned buildings and infrastructural development. The drivers of the urbanization include increasing of urban population, rural-urban migration to the administrative capital of Kargil district, and an increasing mountain tourism sector which led to new constructions of hotels, guesthouses, and arrival of tourists.
Numerical Modeling of Heat Transfer and Thermal Attenuation Lengths in Ventilated Caves
Authors: Sedaghatkish Amir , Pastore Claudio , Jeannin Pierre-Yves , Luetscher Marc , Doumenc Frédéric
Published: February 2023

Atmospheric temperature variations are characterized by different frequency-modes including yearly and daily fluctuations as well as yearly average temperatures. In a ventilated cave, the thermal amplitude is attenuated with increasing distance from the upper and/or lower cave entrance. Convective heat flux for dry air is exchanged with cave wall and the heat transferred by conduction to the surrounding rock is attenuated within a certain distance. Here, we aim at determining the thermal attenuation length for the different modes along a cave and the surrounding rock. Distribution of amplitude of fluctuations along the cave is specified by using Fourier series expansion for dominant modes. In next steps, the effect of latent heat exchange at the cave wall due to evaporation or condensation will be studied. The main variables controlling thermal perturbations in ventilated caves are recognized and compared with field data by developing a numerical model based on the heat and mass transfer between the rock and the air. Moreover, our model aims to quantify the air and wall temperature profile along the conduit for a one-year. The model calculates water-vapor exchange rate along the cave showing the amount of consumed or produced water by evaporation or condensation along the cave and provides the rock temperature distribution in the surrounding hostrock. Our preliminary results contribute to a better understanding of the long-term cave dynamics and may support a quantitative interpretation of speleothem records.
A new crustal balanced cross-section through the Central Apennines (Italy)
Authors: Maresca Augusto , Granado Pablo , Muñoz Josep A. , Manatschal Gianreto , Ogata Kei , Tavani Stefano
Published: February 2023

The Apennines fold-and-thrust belt, forming part of the Africa-Eurasia plate boundary, developed due to the Neogene subduction of the Alpine Tethys underneath Europe and to the subsequent involvement of the Adria rifted margin into the collisional process. Since the Miocene, E-ward retreat of the slab caused extensional deformation to affect the thrust pile, which eventually led to the opening of the Tyrrhenian back-arc basin at the rear of the belt. Multiple schools of thought exist about the structural style of the Apennines, which propose irreconcilable models. The amount of shortening, the involvement of the crystalline basement, the architecture of the inherited rifted system and its degree of reactivation during convergence, and the role played by compressive inheritance during back-arc extension, are still highly debated.In this contribution we focus on the Central Apennines. We integrate publicly available geological maps, interpretation of vintage seismic sections, borehole data, recent seismicity studies, previously published surficial geological cross-sections, and the latest thermochronological insights to build a balanced cross-section across the inner portion of the belt. Our aim is to critically evaluate previous models and to better define its deeper part. Our results suggest a dominantly thin-skinned style, in which inherited Mesozoic extensional faults developed during Adria rifting have been partly reactivated during thrusting. The major thrusts of the area are characterized by large displacements, ranging between 10 and >20 km, and sole into a basal décollement located at the base of the post-Variscan sedimentary sequence. Post-thrusting back-arc extension is accommodated by faults that either displace the compressional décollement levels or reactivate them with opposite kinematics.
The impacts of ground-mounted solar parks on soil health in the UK
Authors: Treasure Lucy , Armstrong Alona , Sharp Stuart , Smart Simon , Parker Guy
Published: February 2023

Soils are a key natural capital asset. Soil health, defined as the capacity of a soil to function as a living system, is a vital component of wider ecosystem processes and functioning, including the flow of multiple ecosystem services. Land use change is an important factor influencing declines in soil health globally. To meet demand for low carbon energy, ground-mounted solar parks (SPs) have expanded rapidly in recent decades, incurring significant land use change, with predictions that UK solar capacity could quadruple by 2050. There is potential for both positive and negative impacts of SPs on soil health - SPs present a relatively unique land use change, in that large areas of land remain physically undisturbed but are shaded by panels. This shading can alter microclimate metrics under panels, including air and soil temperature, soil moisture, photosynthetically active radiation and humidity, which may impact indicators of soil health. Further, the majority of SPs in the UK are developed on former agricultural land, often intensively managed. Arable land use is one of the most detrimental to overall soil health, whilst there is significant evidence supporting the benefits of taking agricultural land out of cultivation, including increased soil carbon, reduced erosion, compaction, and pollution. Considering the land use requirements and microclimatic variation within SPs, it is critical that their impacts on soil health are understood, yet research on solar park-soil impacts remains sparse.We investigated the impact of location within SPs (under solar panels and in gap areas) and the influence of prior land use (arable and grassland) on physical, chemical, and biological indicators of soil health, to address this knowledge gap and provide one of the first quantifications on the impacts of SP development on soil health.  Preliminary results suggest no difference in indicators with SP prior land use, however bulk density and inorganic phosphorus were significantly lower in gap areas compared to under panels, whilst organic matter and microbial biomass carbon were higher in gap areas. These results suggest that soil health may be degraded under the shade of solar panels.However, on-site management decisions such as livestock grazing, wildflower planting and mowing regimes likely influence soil health indicator values and vary across SPs. Further, the SPs studied have been operational since 2014, a relatively short time in terms of soil health. As such, further research is required across spatial and temporal scales, considering the impact of SP management actions to accurately infer SP impacts on soil health.
Future Projections of Heat Waves over India under CMIP6 Scenarios
Authors: Chathu Neethu , Ramesh Kalidahasan Vasanthakumari
Published: February 2023

Anomalous episodes of extremely high surface temperature are heat waves, observational studies have shown that heat wave characteristics like intensity, frequency, and duration are increasing regionally and globally. As heat waves inflict disastrous impacts on the livelihood of millions of people, it is critical in developing suitable mitigation strategies to curtail the socio-economic vulnerability. Future projections at the regional level will be crucial for climate risk management to policymakers. The present study addresses the changes in the heat wave characteristics over the seven temperature homogeneous zones of India, viz. North West, North Central, West Coast, East Coast, Interior Peninsula, Western Himalaya, and North East. We use the historical (1951-2014) and projections (2015-2100) of the Coupled Model Intercomparison Project phase-6 (CMIP6) under different climate change scenarios based on Shared Socioeconomic pathways, SSP126, SSP245, SSP370, and SSP585. The reliability assessment has been carried out and the selected model composite showed good skill than all model composite, in the multiple aspects of observed heat wave features over each zone. The findings show that the projected area of occurrence of extreme daily maximum temperature and long-lasting heat waves (>11 days) are considerably increasing over all zones, where the exacerbating increase is over West Coast under all climate change scenarios.  The heat wave days are likely to increase two times over Western Himalaya and North West,  while the warm days are increasing four-fold over West Coast and double over other zones under SSP370 and SSP585.  The projected changes in heat wave characteristics over North East is below the all-India average. High-intensity heat waves are probably over the coastal zones under the scenario SSP370 and SSP585. Currently, the least heat wave impacted West Coast,  likely to be more vulnerable in the future. The projections show the heat wave characteristics are increasing over all the zones and have a spatio-temporal variation.
Role of buckling and sub-salt basement activity on the evolution of salt pillow structure – insights from numerical models and seismic data from the Polish Basin
Authors: Adamuszek Marta , Krzywiec Piotr
Published: February 2023

The presence of the thick Zechstein (Upper Permian – Wuchiapingian to Changshingian) evaporites strongly controlled deformation style within the Polish Basin that formed the eastern periphery of the epicontinental Permian-Mesozoic Central European Basin System, both during its Triassic to Early Cretaceous subsidence as well as during its Late Cretaceous to Paleogene inversion. Traditionally, formation of Zechstein evaporites has been associated with deposition of evaporitic cyclothems within large depression, with essentially no tectonic influence on evaporitic depo-systems. Furthermore, development of salt structures, in particular of salt pillows, has been commonly attributed to thin-skinned tectonics with minor role played by sub-salt fault zones. A newly developed tectono-stratigraphic model, constructed using seismic data calibrated by deep research wells from the central part of the basin (Bydgoszcz – Szubin area), suggests a significant role of Late Permian localized extension and deposition of syn-extensional Zechstein evaporites within the half-graben controlled by a deeply rooted normal fault. Consecutive basin inversion was associated with substantial uplift of the hangingwall block, formation of salt pillow built of locally overthickened evaporites deposited during active extension, and buckling of the Mesozoic supra-salt overburden. In order to test this new tectono-stratigraphic scenario of deposition and deformation of the Zechstein evaporites our own finite element-based numerical model has been used. In this study, we considered a two-dimensional plane strain model. The deformation was studied using the incompressible Stokes equations. A simplified stratigraphic sequence of the evaporitic series composed of alternated salt and anhydrite layers with a total initial thickness of 1 km has been used as it depicts general characteristics of the initial model constructed using seismic data. In several model runs, various geometrical and mechanical parameters of the salt and anhydrite layers and of the overburden have been considered. Additionally, various scenarios of deformation including the different rates of deformation and fault basement activity have been tested. We also took into account various models of sedimentation and erosion processes. Obtained results fully confirmed that indeed basement localised subsidence and later inversion might have played a much more important role during the deposition of Zechstein evaporites and then during the formation of salt pillows than previously assumed.
On detecting signals of anthropogenic climate change in basin-scale hydrologic variables
Authors: K. Vijayan Anju , P. Mujumdar Pradeep
Published: February 2023

Anthropogenic climate change is one of the most pressing global environmental challenges faced by society in recent times. Large-scale shifts are observed in precipitation and runoff patterns due to the impact of anthropogenic climate change on the regional water cycle. Understanding these impacts is critical for effectively managing and protecting water resources and for mitigating the impacts of climate change. However, the detection of the impact of anthropogenic climate change on the regional water cycle is challenging. A pattern correlation analysis using fingerprints can be carried out to evaluate the impacts of human-induced climate change. Fingerprints give the expected direction of the anthropogenic signal and help to reduce the detection problem to a univariate or low-dimensional problem. This study adopts a formal fingerprint-based detection method to analyze the trends in monsoon precipitation and streamflow in the Krishna River basin, India. In-situ observations and several climate model outputs are utilized for the analyses. Principal component analysis, statistical downscaling techniques, and an Artificial Neural Network (ANN) based rainfall-runoff model are employed. The fingerprint detection method is illustrated using three scenarios by altering the anthropogenic forcings: aerosols alone, land use alone, and a combination of greenhouse gases with aerosols. The hydrologic variables considered are the gridded monthly monsoon precipitation data for 1951-2005 at 1° latitude by 1° longitude and monthly monsoon streamflow at a downstream gauging station. Leading Empirical Orthogonal Functions (EOFs) and signal strength are used to compare the response pattern of observed hydrologic variables with the response pattern simulated by climate models, including various forcings. The hypothesis that the observed trend in hydrologic variables lies within the range expected from natural internal variability alone is validated at a 95% statistical confidence level for most of the climate models considered. This excludes the possibility of other causal factors, including solar irradiance, volcanic eruption, and other anthropogenic impacts. It is found that the signal of human influence is less distinct from that of natural variability. Hence, it is concluded that applying a formal fingerprint-based method is not fully successful in detecting anthropogenic trends in hydrologic variables at the basin scale. The results emphasize the need for robust observational data and advanced analytical techniques considering a detailed process understanding.
Insights on the seismotectonic of Calabria-Lucania border region (Southern Italy): different tectonic styles at different depths
Authors: De Matteo Ada , Capuano Paolo , Falanga Mariarosaria
Published: February 2023

The Calabria-Lucania border region represents the transitional area between the Southern Apennines and the Northern sector of the Calabrian arc. Roughly the whole Apennine chain is struck by more or less intense earthquakes. While the northern and central parts of the chain are characterized by foreland contraction and hinterland extension, the Southern Apennine is characterized by a strike-slip kinematics in the eastern sector and by an extensional regime in the western sector. Strike-slip earthquakes have been observed also in the axial part of the Campania-Molise Apennines, rightly beneath the active extensional sector.The Calabria-Lucania border region is considered a seismic gap in the Apennine chain; few paleo-earthquakes, with magnitude ranging from 5 to 7, have been recorded in the area. During 2010-2014 the region was affected by a low-moderate instrumental seismicity (known as Pollino seismic sequence): thousands of earthquakes occurred. Analysis of that seismicity revealed a shallow hypocentral distribution located into the first few km below the surface, and focal mechanisms of the strongest events of the sequence are consistent with upper crustal extensional deformation. While the shallow seismicity of Calabria-Lucania border region has been deeply studied after the 2010-2013 sequence, the sporadic deep seismicity needs a more detailed analysis.As highlighted by previous studies, instrumental seismicity recorded from 2013 to 2015 reveals the presence of a sporadic deep (from 9 to more than 20 km) seismicity. The events located between 9 and 17 km deep have transcurrent to transpressional kinematics with NE-SW trending P axes; while deeper events show a strike-slip kinematics with NW-SE trending P axes.We analyzed deep (> 10 km) seismicity recorded in the area from 2013 to nowadays. Starting from the picking of seismograms of more than 40 events (with M between 2.4 and 3.8), we analyzed the focal mechanisms of events computed using at least six good first motion observations. According to Ferranti et al., 2017, our results highlight the presence of a strike-slip/oblique kinematics at depths of more than 20 km. Between 10 and 20 km depth both dip-slip and strike-slip kinematics are present, with a predominance of the last ones, confirming the presence of a transition zone.  Finally, we inverted the focal mechanisms dataset to infer about the stress field active in the region.
An investigation of the contributions of VOCs to urban ozone production in the U.K.
Authors: Holland Rayne , Khan M. Anwar H. , Shallcross Dudley
Published: February 2023

Ambient concentrations of 23 volatile organic compounds (VOCs) measured at London Marylebone Road (LMR), an urban traffic site in the UK were analysed over a period of 22 years (1998-2019) to assess the impact of pollution control strategies. A significant decrease in ambient concentration is seen for the majority of VOCs analysed with total VOC burden decreasing by 76% across the period studied, likely as a result of legislative controls. This analysis was extended to consider the contribution of VOCs to ozone formation at this site utilising POCP values. Similarly, the overall reactivity of the VOC burden at LMR has resulted in a significant decrease of just under 12% per year in ozone formation potential over 1998-2019 at this site. The declines in ozone formation potential for VOCs associated with road traffic emissions are all in good agreement at 11-13% decrease per year. VOCs related to non-traffic sources, namely ethane and propane from natural gas leakage, did not see a significant decline over the study period. The variation and composition of the overall VOC burden was compared across three decadal time periods (1998-2000, 2001-2010, 2011-2019) and saw an increase in significance of these pollutants (with ethane and propane moving from the fifth and eleventh largest contributors in 1998-2000 to the first and second largest contributors in 2011-2019, respectively) suggesting they are not sufficiently controlled under current legislation. The increase in significance of ethane and propane was mirrored in their contribution to ozone generation potential but ethene continues to substantially dominate in contribution to ozone formation potential by a factor of 4 and 5 compared with ethane and propane, respectively. Alkanes are typically considered to be less important in the context of ozone formation potential due to their low reactivity in comparison to other VOCs. Analysis presented herein demonstrates the negative impact of ignoring such emissions as their influence begins to grow such that alkanes now represent 3 of the 5 highest contributors to tropospheric ozone formation at this site (in order of contribution: ethene > propene > n-butane > ethane > propane). The importance of high-quality gas-phase kinetic studies to determine the impact of VOCs in ozone production is clear and the usefulness of metrics such as POCPs is demonstrated.
Rain-induced transient variations in glacier dynamics characterized by a continuous and dense GPS network at the Glacier d’Argentière
Authors: Togaibekov Anuar , Walpersdorf Andrea , Gimbert Florent
Published: February 2023

The motion of glaciers with a temperate base is highly variable in time and space, mainly as a result of glacier basal sliding being strongly modulated by subglacial hydrology. Although transient friction laws have recently been established in order to predict short-term sliding velocity changes in response to water input changes, yet little observations enable fully constraining these laws. Here we investigate short-term changes in glacier dynamics induced by transient rainwater input on the Glacier d’Argentière (French Alps) using up to 13 permanent GPS stations. We observe strong surface acceleration events materialized by maximum downglacier velocities on the order of 2 to 3 times background velocities and associated with significant glacier surface uplift of 0.03 m to 0.1 m. We demonstrate that uplift strikingly coincides with water discharge. In contrast, horizontal speed-up occurs over a timescale shorter than discharge and uplift changes, with a maximum occurring concomitantly with maximum water pressure but prior to maximum discharge or uplift. Our findings suggest that transient acceleration and uplift of the glacier are not necessarily modulated by the same mechanism. We also observe that the horizontal speed-ups propagate downglacier at migrating speeds of 0.04 m s-1 to 0.13 m s-1, suggesting an underlying migration of subglacial water flows through the inefficient, distributed system. We demonstrate that the temporal relationship between water discharge, water pressure, and three-dimensional glacier motions are complex and cannot be directly interpreted by changes in the subglacial water pressure through cavity formation and water storage. 
How did anthropogenic forcing influence the exceptional heatwave in the summer of 2022 over the Yangtze River Basin through subtropical high?
Authors: Liang Wenjun , Dong Wenjie
Published: February 2023

The attribution study of extreme weather events has attracted the interests of climate change science communities in recent years. From July–August 2022, an extraordinary heatwave with record-breaking high temperatures occurred in Central and Eastern China, especially over the Yangtze River Basin, for what period the China Meteorological Administration gave the first “red heat warning” in history. Meanwhile, the western Pacific subtropical high leaped over the Tibetan Plateau, which was rarely seen in the past. Understanding the causes of such extreme events and distinguishing the role of human played are both helpful for mitigation and adaptation of climate change, although it is full of challenges. This study used a risk ratio approach (PR) to investigate whether and to what extent atmospheric circulation and other factors (such as anthropogenic climate change, greenhouse gases, and aerosols) contributed to this event, 42 members out of 12 CMIP6 models. According to the CMIP6 simulations, the contribution results show that the existence of anomalous anticyclones would have increased the probability of this extreme heatwave by 4.5 times, making it the main driver for this extreme event in the past 60 years, while the anthropogenic climate change contributed the most (PR = 3.9) for the past 30 years. Additionally, we found that anthropogenic aerosols had no significant impact on the likelihood of this event (PR = 0.82 (0.74) in the past 30 (60) years). This study provides a strong warning that global warming caused by anthropogenic activities in recent decades may result in more frequent extreme heatwaves of summers similar to the summer of 2022. Therefore, measures for mitigating and adapting to global warming are urgently needed.
On the Middle East's severe dust storms in spring 2022: Triggers and impacts
Authors: Francis Diana , Fonseca Ricardo , Nelli Narendra , Bozkurt Deniz , Cuesta Juan , Bosc Emmanuel
Published: February 2023

Large amounts of dust in the air can disrupt daily activities and pose a threat to human health. In May 2022, consecutive major dust storms occurred over the Middle East resulting in severe environmental, social and health impacts. In this study, we investigate the exceptional factors driving these storms and the effects of the dust clouds. Using a combination of satellite, in-situ and reanalysis datasets, we identify the atmospheric triggers for the occurrence of these severe dust storms, characterize their three-dimensional structure and evaluate the dust radiative impact. The dust emission was promoted by density currents emanating from deep convection over Turkey. The convective systems were triggered by cut-off lows from mid-latitudes fed by moisture from African atmospheric rivers. Data from the Infrared Atmospheric Sounding Interferometer (IASI) showed that the dust clouds were transported southward at 4 km in altitudes but sunk to ground levels when they reached the southern Arabian Peninsula due to strong subsidence. At a station in coastal UAE, the dust caused a 350 W m−2 drop in the surface downward shortwave flux and a 70 W m−2 increase in the longwave one during the dust episodes. This contributed to a 9 °C increase in nighttime temperatures which exacerbated the effects of the heat for the population. The newly highlighted mechanism for dust emission in the Middle East, in which a cut-off low interacts with an atmospheric river, as well as direct observations of the dust impact on the radiative budget can contribute to reducing associated uncertainties in climate models.
Resilience Analysis of Power System for Seismic Disaster Mitigation
Authors: Chen I-Yun , Lin Szu-Yun
Published: February 2023

Natural disasters may severely impact critical infrastructure and lifelines and even cause the shutdown of essential facilities. This research proposes a novel assessment framework for earthquake risk and resilience of the power system. It aims to find the most feasible disaster prevention and emergency strategies to improve community resilience by comprehensively considering the 4R (Robustness, Rapidity, Redundancy, Resourcefulness) indicators. In this study, the power system in Taipei City was adopted as the case study. Graph Analysis was first conducted to analyze the centrality of each station and the influence after its breakdown for determining the critical nodes. Then, Monte Carlo simulations were carried out to simulate the damage and recovery of the power system under the considered earthquake scenario. Also, the quantitative measurements for Robustness, Rapidity, Redundancy, and Resourcefulness of the power system have been well-defined individually. The high-risk and vulnerable areas in the case study are recognized. Afterward, based on the results of multi-objective optimization, the optimal disaster prevention and emergency strategies from 4R perspectives can be investigated. The result indicates that the critical power plants and substations can be served as the priority protection targets. However, with limited resources, there is a trade-off between 4R, such as enhancing resisting capacity in advance, providing alternatives during a disaster, or accelerating the restoration of the power system in the aftermath of earthquakes. By comparing the obtained optimal resilience strategies with the government's current policies, the feasibility of the strategies can be discussed. The goal of the research is to enhance the resilience performance of cities when facing disasters. The assessment framework can be applied to other lifeline systems, and the interdependencies between different critical infrastructures should be taken into account in future studies.
MESSENGER observations of short, large-amplitude magnetic structures (SLAMS) in the Mercury foreshock
Authors: Karlsson Tomas , Plaschke Ferdinand
Published: February 2023

We have investigated approximately four years of MESSENGER data to identify short, large-amplitude magnetic structures (SLAMS) in the Mercury foreshock. Defining SLAMS as well-defined structures with a magnetic field strength of at least a factor of 3 higher than the background magnetic field, when MESSENGER is located in the solar wind, we find 435 SLAMS. The SLAMS are found either in regions of a general ultra-low frequency (ULF) wave field, at the boundary of such a ULF wave field, or isolated from the wave field. We invetigate several properties of the SLAMS, such as temporal scale size, amplitude, and polarization. We find that SLAMS are mostly found during periods of low interplanetary magnetic field strength, indicating that they are more common for higher solar wind Alfvénic Mach number (MA). We use the Tao solar wind model to estimate solar wind parameters to verify that MA is indeed larger during SLAMS observations than otherwise. Finally, we also investigate how SLAMS observations are related to foreshock geometry.
Impact of Spatio-Temporal Disaggregation of Rainfall on Hydrological Modelling
Authors: Harini Vemuri , Wadhwa Abhinav , P. Mujumdar Pradeep
Published: February 2023

Uncertainty assessment of rainfall patterns and the accompanying hydrological effects is essential to formulate effective adaptation strategies. Although the problem of equifinality in hydrological modelling has long been debated, its impact on hydrological analysis has not been sufficiently investigated. Traditional calibration techniques assume that input error is minimal, which might add a bias to the parameter estimates and impair the model predictions. Existing methods to overcome this issue are often weak due to both challenges in comprehending sampling errors in rainfall and processing limitations during parameter estimation. Such approaches consider structural and parameter uncertainties, whereas input and calibration data errors are often unaccounted for. This study aims to enhance the computational effectiveness of uncertainty analysis and separate the sources of uncertainty. Also, the implications of model input uncertainty to coupled human-natural-hydrologic systems and environmental changes are evaluated. A regression-based technique is developed to measure the level of uncertainty in the monsoon precipitation patterns for an urban catchment in Bangalore city, India. Sub-hourly rainfall datasets for various stations are estimated using disaggregation techniques such as scale-invariance and k-nearest neighbours-based methods. These datasets are fed into a hydrological model to connect the proposed method with the common framework for hydrological modelling. The findings demonstrate that the performance of a hydrological model is highly dependent on the spatio-temporal scale of the input rainfall in urban catchments where flash flood situations are envisaged.
Thermo-Acousto-Elasticity (TAE) of natural rock cliffs: toward better understanding and monitoring damage and erosion process
Authors: Larose Eric , Guillemot Antoine , Baillet Laurent , Bottelin Pierre
Published: February 2023

Rainfalls and freeze-thaw cycles are well known to largely contribute to rock slopes erosion, including chemical processes (dissolution, alteration) together with mechanical action (stress change in fractures due to water freezing). The role of heat waves and thermal cycles is less studied in dry conditions. Here we present a thermo-acousto-elastic (TAE) model for rock volumes exposed to cyclic (daily to seasonal) thermal forcings, as an application of environmental seismology (1).In our model, we assume that the rock temperature is constant at depth (a few meters in general), and that the free surface is exposed to heat fluxes (radiative and convective ones). In practice, these heat fluxes can be respectively derived from solar radiation normal to the rock surface and from the air temperature, both parameters are easily measured in the field. We then develop a numerical model based on a) thermal diffusion (heat propagation in the rock in 2D or 3D models, including complex geometries as cracks, rock columns…), b) thermal expansion relating temperature to strain, and c) acousto-elasticity relating the elastic parameters to the state of stress, (2). Such a model is run, for example, with COMSOL Multiphysics with a finite element scheme. We end up with a 2D or 3D numerical model of stress and deformation of the rock volume evolving over time ranging from sub-daily to yearly time scales.As an application we test this model on various rock columns and observe that the developed model properly reproduces field observations, including daily and seasonal cycles: the natural resonance frequency of the rock column, a proxy for its rigidity, increases with increasing heat flux (3) and the rear crack closes up. As a result of fitting our numerical model to natural rock columns, we can evaluate the acousto-elastic constant that relates the rigidity to the state of stress, a parameter that is known to mainly depend on the state of damage of the material, opening the route for rockfall risk assessment, monitoring and early warning systems. Our model also allows to shed new light into fatigue and cyclic damage process of rock slopes and cliffs, a key to rock erosion. References:(1) Guillemot, L. Baillet, E. Larose, P. Bottelin : Changes in resonance frequency of rock columns due to thermoelastic effects on a daily scale : observations, modeling and insights to improve monitoring, Geoph. J. Int. 231, 894-906 (2022).
(2) Larose, E. & Hall, S.: Monitoring stress related velocity variation in concrete with a 2.10−5 relative resolution using diffuse ultrasound, J. acoust. Soc. Am., 125, 1853–1856 (2009).
(3) Bottelin, P., Levy, C., Baillet, L., Jongmans, D. & Gueguen, P.: Modal and thermal analysis of Les Arches unstable rock column (Vercors massif, French Alps), Geophys. J. Int., 194, 849–858 (2013).
Field hydrological monitoring with IoT-based low-cost sensor network on slopes subjected to rainfall-induced landslides
Authors: Marino Pasquale , Roman-Quintero Daniel Camilo , Santonastaso Giovanni Francesco , Greco Roberto
Published: February 2023

Many mountainous areas of Campania, Southern Italy, are characterized by steep slopes covered by layered granular unsaturated pyroclastic deposits, mainly consisting of ashes and pumices, laying upon fractured limestone bedrock. The total thickness of the soil is quite variable with a few meters (1.0 m–1.5 m) in the steepest part of the slopes, and larger at the foot. Shallow landslides are often triggered after large and intense precipitations, turning into destructive debris ﬂows that cause heavy damage and victims. The slope of Cervinara, located around 40 km Northeast of Naples (Campania, Italy), was involved in a catastrophic debris flow between 15-16 December 1999, triggered by a rainfall event of 325 mm in about 48 h. Since 2001, hydrological monitoring activities have been carried out at the slope, by measuring precipitation depth, soil volumetric water content and capillary tension. Moreover, in December 2017 an automatic hydro-meteorological station has been installed at the elevation of 575 m a.s.l., near the scarp of the 1999 landslide. It allows the assessment of slope hydrological balance, by identifying the major hydrological processes involving the cover and the perched aquifer, which develops in the upper part of the fractured bedrock during the rainy season. Lately, since 1 December 2022, new monitoring activities started. A remotely accessible low-cost network has been installed moving away from the landslide scarp of 1999, for expanding the area interested by soil moisture monitoring. The tested prototype network is based on the use of capacitive sensors placed at nodes located 20 m apart from each other with a communication system within the domain of Internet of Things (IoT) technology. Specifically, the low-cost sensors network allowed measurements of soil water content, communicating through short-range wireless IoT system (i.e., Wi-Fi) thanks to ESP32 boards. The field data can be visualized remotely on ThingSpeakTM IoT platform on laptops and smartphones.The tested IoT-based low-cost network shows the potential to enhance the amount of monitored hydrological data at affordable cost, so to improve risk management in landslide-prone areas. The same IoT network architecture with diffuse measurements can be replicated with long-distance radio communication between nodes, which allows extending the mutual distance up to few kilometers.
Regional gravitational field modelling by the spectral combination of satellite higher-order radial derivatives of the gravitational potential and a global geopotential model
Authors: Pitoňák Martin , Šprlák Michal , Novák Pavel
Published: February 2023

In this contribution, we will discuss a problem of regional gravitational field modelling by the spectral combination of spaceborne first-, second- and third-order radial derivatives of the gravitational potential at the mean altitude of 250 km. Some of the mentioned measurements are not observable yet, so we will synthesize them from a global geopotential model over a test area. The main goal of a numerical experiment is to compute the gravitational field in a regional area from spatially restricted higher-order radial derivatives of disturbing potential, and two problems arise. The first is how to estimate local spectral properties, i.e., degree-order variances of local data, and the second is the effect of the omitted distant zone data, i.e., (spatial) truncation error. The spherical harmonic power spectrum from local data will be recovered by 2D-DFT, and the truncation error will be calculated from a global geopotential model. For this purpose, a mathematical model based on the spectral combination method of heterogeneous gravity field data and a global geopotential model is developed. The correctness of derived spectral weights suitable for spectral downward continuation will be verified by a closed-loop test and by direct comparison with the global solution. Moreover, different sizes of a data area (area covered by simulated satellite measurements) to minimize the truncation error and various truncation degrees of a global geopotential model will be tested.
Lagrangian Spatiotemporal Fingerprints of Dissolved Inorganic Carbon in Eighteen Degree Water Formation
Authors: Reijnders Daan , Bakker Dorothee , van Sebille Erik
Published: February 2023

Mode waters are defined as thick, weakly stratified layers with homogeneous properties. They have the ability to store these properties, such as heat, carbon and nutrients, and exchange these with the surface or atmosphere during outcropping events or with other layers via mixing processes. Eighteen Degree Water (EDW) is the subtropical mode water of the western North Atlantic. Its yearly outcropping events in late winter makes it an important regulator of ocean heat, nutrients and carbon in the North Atlantic on annual timescales.Previous studies have given insight into the formation and destruction of Eighteen Degree Water. These have largely focused on physical aspects such as EDW formation rates. Due to the importance of EDW formation in setting the biogeochemical environment in the North Atlantic, it is instructive to investigate how biogeochemical tracers are altered along EDW formation routes. This study investigates in particular how dissolved inorganic carbon (DIC) is altered along ocean water parcel trajectories as EDW is formed. To do so, we compute Lagrangian trajectories of subducted EDW backwards in time using a coupled hydrodynamic and biogeochemical model. By sampling biogeochemical tracer values along Lagrangian pathways, we construct timeseries which we use to map the dominant locations at which DIC concentrations are altered in space and time to identify the Lagrangian fingerprint of DIC in Eighteen Degree Water.
The path from scientific to operational flare forecasting: a deep learning approach
Authors: Guastavino Sabrina , Marchetti Francesco , Benvenuto Federico , Campi Cristina , Massone Anna Maria , Piana Michele
Published: February 2023

In our view, machine/deep learning for flare forecasting is still more a promise for future scenarios than the reference framework for current operational facilities. This delay from the application of AI methods in research settings to their use for real-time forecasting is probably due to the persistence of technical open issues involving, by instance, the optimization strategy of the training phase, the quantitative assessment of the prediction performances, the reduction of the computational burden. This talk proposes a video-based deep learning approach to flare forecasting in which the optimization of the network’s parameters is realized by means of a probabilistic score-oriented loss function, the training procedure accounts for the part of the solar cycle progression when the prediction is requested, and the prediction performances are assessed by means of value-weighted skill scores that give greater importance to the values of the prediction than to its quality. The talk will also show the operational potentialities of this approach and discuss how feature selection may reduce the information redundancy, thus increasing the computational efficiency.
Update of the Seismogenic Potential of the Upper Rhine Graben Southern Region
Authors: Michel Sylvain , Duverger Clara , Bollinger Laurent , Jolivet Romain , Jara Jorge
Published: February 2023

The Upper Rhine Graben (URG), located in France and Germany, is bordered by north-south trending faults, some of them considered active, posing a potential threat to dense population and infrastructures from the Alsace plain. The largest historical earthquake in the region is the 1356 Basel earthquake associated to a magnitude M6.5+/-0.5. Current seismicity (M>2.5 since 1960) is mostly diffuse and located within the graben. The seismic hazard of the URG southern region was recently assessed by Chartier et al. (2017). In this study, we build upon their evaluation by exploring uncertainties in greater detail, revisiting a number of assumptions. Based on a complex fault network from Nivière et al. (2008), we evaluate scenarios that have not been taken into account previously, exploring uncertainties on Mmax, its recurrence time, the b-value, and the moment released aseismically or through aftershocks. Uncertainties on faults’ moment deficit rates, on the observed seismic events’ magnitude-frequency distribution, and on the moment-area scaling law of earthquakes are also explored. Given the four faults considered, and the scenario in which the Black Forest fault is not active anymore but where the other faults can still rupture simultaneously, and assuming only a dip-slip mechanism, the Mmax maximum probability is estimated at Mw5.95. Considering this scenario, there would be a 99% probability that Mmax is below 7.15. In contrast, considering instead strike-slip, as suggested by paleo-seismological work from Castellnou et al. (2022), and taking the Black Forest Fault into account, Mmax maximum probability is estimated at Mw6.85. Based on this scenario, there would be a 99% probability that Mmax is less than 7.65.
Qualitative and quantitative analysis of synthetic polymers in ambient aerosols by Curie Point Pyrolysis-Gas Chromatography/Mass Spectrometry
Authors: Kaushik Ankush , Mekic Majda , van Pinxteren Manuela , Herrmann Hartmut
Published: February 2023

Nano- and microplastics (NMP), including tire wear particles (TWP), are now a global concern in the terrestrial and marine environment and are subject of intense study. The existence of NMP and TWP in many different environments has been reported, including soil, sediment, dust, glaciers, lakes, rivers, seas, and oceans. However, only a few studies have examined the abundance and fate of synthetic polymers in ambient aerosol particles. The dispersion, atmospheric transport and deposition of NMP and TWP are important steps in the biogeochemical cycle of plastic. The inconsistencies in the methods of sampling, processing, analysis, and the Quality Assurance (QA)/ Quality Control (QC) procedures of NMP and TWP hinder our ability to examine these contaminants' spatial and temporal patterns in the atmosphere. Based on the previously reported research on the analysis of NMP and TWP in the air, it becomes necessary to develop a comprehensive standard methodology that should be established for detecting microplastics in the atmosphere at submicron level (PM10 and PM2.5). Since synthetic polymers are difficult to quantify at low concentrations, Pyrolysis-Gas Chromatography coupled with Mass Spectrometry provides an effective technique for detecting NMP and TWP. As part of the present study, we aim to develop and provide methods and measurement approaches that would facilitate the routine analysis of PM10 and PM2.5 samples for synthetic polymers in aerosol particles in terms of mass concentrations using Curie Point Pyrolysis-Gas Chromatography coupled with Mass Spectrometry (CPP-GC/MS). To follow this, reference standards were milled using a cryo-mill, and a calibration curve was obtained for the most common synthetic polymers present in the atmospheric environment, such as Polystyrene (PS), Polypropylene (PP), Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Low-Density Polyethylene (LDPE), Polyvinyl Chloride (PVC), Poly(methyl-methacrylate) (PMMA) and Styrene Butadiene Rubber (SBR). The present study determined the Limit of Quantification (LOQ) and Limit of Detection (LOD) of each standard by analysing it at different concentrations down to the lowest level with acceptable repeatability and accuracy. The current method of quantifying synthetic polymers was tested by spiking experiments on aerosol samples (PM10 and PM2.5) at different concentrations. This study examines open research questions in various main areas, including developing analytical methods, size-resolved sampling, and analysing NMP and TWP in ambient aerosol particles in urban, rural, and remote areas.Keywords: Nano- and microplastics, tire wear particles, synthetic polymers, Curie Point Pyrolysis-Gas Chromatography/Mass Spectrometry.