bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Exploration of the Morphodynamic Regime Diagram for Straight Channel River Flows
Authors: Weber Francesco , Toffolon Marco , Dijkstra Henk A. , Colombini Marco , Siviglia Annunziato
Published: March 2024

Self-organising phenomena play a crucial role in river systems, from the catchment scale to the single morphological unit. Many studies on morphological patterns in straight channels have been conducted, but full regime diagrams in fundamental parameters (e.g. aspect ratio and mobility parameter) are not known yet.  However, determining such morphological regimes is crucial for prediction of river dynamics and consequently for a range of applications, from flood risk assessment to ecological management and restoration projects.This study employs a 2D numerical model based on spectral methods to explore these morphodynamic regimes in a straight channel, a first approximation of most existing managed rivers. The model couples the depth-averaged shallow-water and continuity equations for the flow and the Exner mass-conservation equation for the sediment. The morphological patterns arising from the simulations are explored in a wide range of parameter space, beyond the critical values for bar formation used in perturbation methods. A thorough taxonomy of planforms and their complexity is generated, resulting in a morphodynamic regime diagram for straight channel flows. Moreover, both the spatial and temporal characterisation of the solutions is carried out, and the presence of quasi-periodic and chaotic behaviour is investigated.
Unveiling coupling properties of subduction zones with novel telesismic waveform approaches
Authors: Rappisi Francesco , Craig Tim , Rost Sebastian
Published: March 2024

Subduction zones are among the most active tectonic areas on the planet. Their primary characteristic is the enormous amount of stress accumulated at the interface between the subducting oceanic plate and the overriding plate. The release of this stress is accommodated by a wide range of behaviours, ranging from aseismic slip (slip at speeds too slow to radiate seismic energy), through the spectrum of slow slip and tremor, to seismic slip capable of generating major earthquakes. The main investigative tools for subduction zones to map out this range of behaviour, and to assess the coupling properties of the subduction interface, involve the direct observation of ground movements through geodesy (either terrestrial or satellite-based) or through local seismic surveillance using near-field instrumentation, all of which are logistically complex, and typically only feasible on land.Utilizing the recent expansion of seismic arrays in continental regions, we propose an alternative approach for the study of subduction zones that bypasses the aforementioned limitations through the use of teleseismic waves—recorded at a distance between 30º and 90º from the epicenter—based on the identification of the presence (or absence) of highly reflective layers at the megathrust interface. Previous studies using local seismic data have observed the presence of highly reflective layers, characterized by strong impedance contrasts, located at the megathrust interface, capable of producing a reflection in the wavefield that results into the presence of precursors of depth phases. Since impedance contrasts in the solid Earth are linked to variations in the elastic properties of the medium, reflectivity offers a window into the rheology of the plate interface. Understanding the reasons behind such strong impedance contrasts, their potential variability over time and space, could pave the way for understanding why the degree of coupling of subduction interfaces varies, whether it is related to transient processes, or if it is stable over time.Here, we present an automated waveform processing approach designed to detect such reflections in remote seismic data, and illustrate this with a test region from the Central America subduction zone.  We analyse waveforms produced by seismic events with magnitudes ranging from 4.5 to 5.5 occurring at different times and recorded by small aperture seismic arrays. Our observations in Central America prove to be an excellent tool for studying the coupling properties of the megathrust interface. This work represents a first attempt, with the ultimate goal of mapping subduction zones and their coupling properties, even in currently inaccessible submarine areas, allowing for a better understanding of the seismic risk that subduction zones represent.
Perception of volcanic risk in communities close to a monogenetic volcanic field: the case of Olot (Garrotxa Volcanic Field, Catalonia)
Authors: Cerda Daniela , Geyer Adelina , Bolós Xavier , Pedrazzi Dario , Morin Julie
Published: March 2024

Nowadays, volcanic eruptions pose a significant threat to society, particularly in monogenetic volcanic fields where prolonged recurrence periods lead to increased human settlements in their vicinity. This is mostly attributed to a false sense of security within the community potentially exposed to a future eruptive event. Such misconceptions often result in a lack of preparedness programs and resilience capabilities for potential future eruptions.In this context, the city of Olot (~34,400 inhabitants, Catalonia, Spain), located within the Garrotxa volcanic field, serves as an example of human settlement around monogenetic volcanoes, which the last known eruption occurred ~ 10.4 – 15.7 ka ago. Although communities residing in this volcanic field demonstrate a sound understanding of their environment, there is a prevalent misconception regarding volcanic hazards, which often leads to perceive the area as inactive or even extinct. To evaluate the perception of volcanic risk among the population of Olot, we have conducted a survey segmented by age groups. The main objectives are: (i) identifying knowledge gaps and misconceptions within the population; (ii) analyzing the factors most relevant in determining risk perception within the community; (iii) contributing to the assessment of the population's resilience in the face of a future eruptive event: and (iv) ultimately evaluating the contrast between the perception of the Olot community and its actual volcanic risk. This work was funded by the BECAS CHILE- ANID, PhD Scholarship Abroad, announcement 2022/Folio 72220257.
Parameterization-based uncertainties in RegCM simulations over Hungary in a dry year – a case study 
Authors: Kalmár Tímea , Pongrácz Rita
Published: March 2024

Drought is one of the natural hazard risks that badly affect both agricultural and socio-economic sectors. Hungary, which is located in Eastern Europe, has already been suffering from different drought periods, and the driest year since 1901 was 2011 when the annual precipitation in Hungary was only 72 percent of the normal value. To better understand droughts and to provide information for adaptation strategies and risk-management systems, there is a strong need for a methodological framework to simulate drought events. However, it is uncertain whether climate models can simulate extreme droughts given the well-known model bias of simulating too light rainfall too frequently. So, the aim of the current study is to investigate the effects of the different model settings on the reproduction of drought characteristics.In order to quantify the impact of the use of different parameterization schemes on regional climate model outputs, hindcast experiments were completed applying RegCM4.7 to the Carpathian region and its surroundings at 10-km horizontal resolution using ERA-Interim reanalysis data as initial and boundary conditions. In this study, we are testing various combinations of the physics schemes (land surface, microphysics, cumulus and boundary layer schemes) for the year 2011. Each parameterization combination leads to different simulated climates, so their spread is an estimate of the model uncertainty arising from the representation of the unresolved phenomena. The analysis of the RegCM-output ensemble indicates systematic precipitation biases, which are linked to different physical mechanisms in the summer and winter seasons.Based on the results, RegCM is sensitive to the applied convection scheme, but the interactions with the other schemes (e.g., land surface or microphysics) affect the precipitation. Due to the different treatment of moisture in the schemes, there are differences not only between the representation of the precipitation cycle, but also in other climatological variables such as soil moisture, latent and sensible heat fluxes and cloud cover, which affect the drought characteristics. The research was funded by the NKFIH-471-3/2021 project (the National Multidisciplinary Laboratory for Climate Change, RRF-2.3.1-21-2022-00014).
Water vapor movement and utilization with condensation in the upper layers of a sandy soil column
Authors: Sekhri Simran , Kleinschmidt Volker , Eschenbach Annette , Becker Joscha N
Published: March 2024

In semi-arid and arid regions, prolonged dry spells lead to a significant reduction in topsoil moisture, forming a dry soil layer, where water can only move as vapor. Such conditions hinder young crops with weakly developed root systems to directly reach deep water reservoir. Since there is no indication of gaseous water uptake from soil pores, plants might be able to acquire water from these deep sources when water vapor condensates at night or at a vapor barrier (mulch). To trace potential water vapor uptake by plants, we developed a sand column experiment using deuterium labeled water. The water source column was separated by a glass bead layer and a root barrier (50µm mesh) from the soil to ensure that there was no capillary rise or root uptake of liquid water. Four treatments with three replicates, including planted (Pl), unplanted (Un), mulch variation (Pl+M; Un+M) and an additional unlabeled control column, were installed in a climatic chamber. Vigna radiata a moderately drought resistant plant species was selected for this experiment. Constant day-night cycle with stable temperature and light conditions were maintained for a period of seven days without irrigation. Afterwards, soil samples were collected at 0-5, 5-10 and 10-15 cm depths. Vigna radiata saplings and condensed water samples were collected separately. Cryo-extraction of water from the samples and liquid isotopic water analysis revealed substantial results for the uptake of water vapor by young saplings. Evaporation from the water source into the column was recorded to be 0.7-2.1 ml. The δD/H ratios were analysed using Triple Isotope Water Analyser (Los Gatos Research). The relative potential uptake of water vapor by young saplings was recorded to be as high as 0.56ml for the 'Pl' and 0.35ml for the 'Pl+M' treatment. The utilization of water vapor by young plants in the upper soil layer could prolong plant life during dry spells. Although, it remains uncertain to what extent the prolongation could be maintained.Keywords: Deuterium Labeled Water, Plant Vitality, Water Conductivity
Characterization and socioeconomic impacts of the late 19th Century drought episodes in Catalonia (NE Iberian Peninsula)  
Authors: Barriendos Josep , Barriendos Mariano , Gil-Guirado Salvador , Gorostiza Santiago , Montávez Gómez Juan Pedro , Andreu-Hayles Laia
Published: March 2024

Recent droughts in the Mediterranean region are increasing concerns on the current and future water resources availability in this region. For this reason, studying the most severe droughts of the recent past and their associated societal responses is key to better characterise the current drought episode ongoing in Catalonia since 2021, as well as to properly define future adaptation strategies. One of these episodes of great magnitude and significant impact on economic and social activity were the droughts that occurred in Catalonia (North-East of the Iberian Peninsula) during the last third of the 19th century (1860-1890). Here, we analyse these droughts using data obtained from administrative documentary sources and instrumental meteorological records. Administrative sources were obtained from local civil and ecclesiastical authorities of eight different locations, as well as from one large irrigation community (Urgell’s Channel Irrigator’s Guild, since 1862). These historical documentary sources provide qualitative information at a daily resolution about drought impacts on the society. Together with the historical data, we also analyse different instrumental precipitation series using the Standardized Precipitation Index (SPI). This data provides a wider spatio-temporal perspective of drought behaviour for the entire Spanish territory during the study period. This study uses existing instrumental precipitation series for Spanish territory spanning from the mid-late 19th Century, with a total of 18 instrumental precipitation series obtained from INM (Spanish National Meteorology Institute). Additionally, we use 66 precipitation series in Spain obtained from the AEMET (Spanish Agency for Meteorology). This joint use of historical and instrumental data allows us to perform a spatio-temporal clustering of drought events to contextualize the intensity and persistence of the severe droughts occurring from1860 to 1890 in Catalonia. Finally, we complete the analysis of drought episodes examining their social impact, we also explore statistical data (Spanish State Statistical Year Books) from economic activities and other social variables.
From pore to well - identifying clay mineral distribution in sandstones using SWIR spectroscopy
Authors: Bublik Dmitry , Mulder Sebastian , Miocic Johannes
Published: March 2024

Fluid extraction from geological formations for purposes of subsurface utilization leads to a pore pressure drop in reservoirs and potentially to compaction and seismicity. The geomechanical behaviour, and thus production-related compaction, of siliciclastic reservoirs is governed by the composition of reservoir sandstones, which includes porosity, grain size distribution, and detrital and authigenic mineralogy.One siliciclastic reservoir which is undergoing compaction related to fluid extraction is the Rotliegend of the Groningen gas field. In this research, we investigate potential approaches to upscale the sandstone composition from the micro-scale (thin sections, plugs) to the well and reservoir scale eventually.Previous research has highlighted that among the petrographic properties, the presence of authigenic clays tends to affect the geomechanical behaviour the most. Intragranular clays can affect the overall stiffness of the individual grains while the presence of the pore-filling clays  and clay rims may result in grain slip or pressure solution in loaded rock samples. In particular, we are defining the fractions of the clay-coating minerals (illite, kaolinite, etc.) and their effect on the inelastic deformation of reservoir sandstone as well as paying close attention to the presence of chlorite as its distribution corresponds to the areas associated with increased subsidence and seismicity.We employed Short-Wave Infrared (SWIR) spectroscopy, a non-destructive and time-efficient technique, to obtain the mineralogical composition of core slabs from the Groningen Gas field. The SWIR data, based on a resolution of 200 µm pixels, allows for a detailed analysis of compositional variation within the Upper Rotliegend Group. Verification of the SWIR results against a comprehensive petrographic dataset, including X-ray diffraction, thin section descriptions, and modal point count analysis highlights that SWIR data primarily captures qualitative variations in mineralogy rather than providing precise numerical values. Combination of sedimentary facies, SWIR spectroscopy data and conventional petrographic studies allows to generate descriptive mineralogical trends for each of the studied wells.Ultimately, the results of our research will serve as a foundation for selecting the samples, designing geomechanical experiments to test the proposed hypotheses, and as the means to select the upscaling and modelling approaches to develop a detailed model of the Dutch subsurface that matches well the existing heterogeneous structures. The derived 3D reservoir composition model of the Groningen gas field will be combined with the results of the deformation experiments to link reservoir composition to geomechanical behaviour. This will enable an updated, more realistic, 3D geomechanical model of the Groningen gas field that can be utilised by other researchers to better predict future compaction and subsidence.
Asperities in sliding surfaces as frictional bridges. Negative friction
Authors: Pasternak Elena , Dyskin Arcady
Published: March 2024

The sliding surfaces of faults and shear fractures in rocks are rarely smooth. They possess local undulations or asperities that act as distributed points of sliding disturbance. These asperities work as bridges connecting the opposite sliding surfaces and creating forces that non-linearly depend on deformation. These forces can even act in the direction of sliding. The mechanism of generating these forces is the local dilation caused by the fact that the sliding makes some asperities of one surface climb over the asperities of the opposite surface in the presence of the external compressive stress. Therefore, the dilation creates an effective friction angle which is the original (microscopic) friction angle controlling friction between the surfaces of the opposite asperities plus the inclination angle between the tangent line to the asperity surfaces at the point of contact and the direction of the movement. The inclination angle depends upon the position of the contact between the asperities making the effective friction angle non-linearly dependent upon the displacement. After passing the point of maximum dilation, the inclination angle becomes negative. Therefore, depending upon the surface friction angle, the effective friction angle can become negative. This creates the effect of local negative stiffness, where the energy is supplied by the convergence of the opposite faces of the fault/fracture (after the top of the contacting asperity is passed) in the presence of the external pressure. The development of the zones of negative friction which are the zones of energy release can be accompanied by microseismisity (one zone - one signal) generated without involving local fracturing. Understanding this mechanism will contribute to refining of the existing monitoring methods of faults/fracture movement.Acknowledgement. The authors acknowledge support from the Australian Research Council through project DP190103260.
Measurements of Atmospheric Aerosol with the Vaporization Inlet for Aerosols and the Filter Inlet for Gases and Aerosols on a Bipolar Multi-Reagent Chemical Ionization Mass Spectrometer
Authors: Alton Mitchell , Canagaratna Manjula , Avery Anita , Lambe Andrew , Kangasluoma Juha , Ehn Mikael , Mickwitz Valter , Zhao Jian , Worsnop Doug
Published: March 2024

Atmospheric aerosols can be composed of a wide variety of organic and inorganic chemicals, which can dramatically affect the environmental impact of the particles. Understanding the chemical composition of aerosol assists in understanding the sources and fate of these emissions. Additionally, as volatile chemical products (VCPs) have surpassed vehicle emissions in urban areas, there is a need to understand the changing composition of urban aerosol and how it affects aerosol loadings and formation. Here, I present a simple tool called the Vaporization Inlet for Aerosols (VIA) to vaporize ambient aerosol to measure the chemical composition of the resulting gas-phase products with a time-of-flight chemical ionization mass spectrometer. The laboratory results from the VIA are compared to those obtained from the previously characterized Filter Inlet for Gases and Aerosols (FIGAERO). Both inlets have different benefits in terms of temporal resolution, gas-phase comparisons, ease of use, and long-term operation, which will be discussed. Finally, the thermal decomposition products of organic molecules in the VIA is compared to the FIGAERO to understand the chemical formulas detected by the mass spectrometer.
European Windstorms: bridging the gap between fundamental research and practical applications
Authors: Pinto Joaquim G.
Published: March 2024

Windstorms are extreme midlatitude cyclones and one of the major natural hazards that cause damage and losses in Europe. While the processes involved in their genesis and intensification are generally well understood, there are still considerable uncertainties in the estimation of associated impacts like widespread wind damage and flooding. The compounding characteristics of the events further enhances the complexity of this task. This is even more true for the impact forecasting of windstorms on weather and sub-seasonal time scales. Additionally, there are large uncertainties on how windstorms and their impacts will change in a warmer climate, particularly regarding the role played diabatic processes in a warmer atmosphere. This study presents examples of recent developments regarding windstorms and discusses some new avenues for interdisciplinary research towards bridging the gap between fundamental research and practical applications.
Teng: Indigenous-Nature-Based Solutions for Sand Mitigation in Sistan Region, Iran - A Comprehensive Approach to Climate Resilience and Sustainable Development
Authors: Jarkeh Mohammadreza , Shahriari Ali , Miri Abbas , Ahmadian Saghar , Middleton Nicholas
Published: March 2024

Climate change presents unprecedented challenges to ecosystems and human communities, necessitating innovative and eco-friendly solutions to bolster resilience. Deeply interconnected with nature-based solutions, indigenous knowledge establishes a synergistic link between traditional wisdom and sustainable environmental practices. Combining insights from generations of indigenous communities deeply rooted in their ecosystems with the regenerative capacities inherent in nature-based solutions, a holistic, effective strategy could emerge to address climate change impacts.
The study focuses on an indigenous-nature-based solution for sand mitigation, where wind-transported sand occupies a substantial portion of the region. The arid climate and water policy changes upstream have led to the desiccation of wetlands and increased sandstorms, posing ecological and social challenges. Despite these adversities, the local communities in Sistan showcase effective measures rooted in indigenous knowledge to mitigate the impact of blowing sand. Their mitigation measures, i.e., Teng, generally a composition of woven branches of Tamarisk trees acting as a barrier to divert/or settle the blown sands. Their approach not only safeguards infrastructure but also utilizes sand as a valuable resource for soil improvement in agriculture.
This research sheds light on the role of such expertise in risk reduction from blowing sands. By delving into its transmission across generations and dynamic adaptation to changing environmental conditions, the research contributes to a deeper understanding of how indigenous knowledge and nature-based solutions can synergistically address the challenges of a rapidly changing climate. This research supports a complete and culturally aware plan for climate challenges. It highlights working with nature as the key to creating sustainable strategies for adapting to changes.
Methane’s record rise 2020-2023: likely causes, impacts and consequences
Authors: Manning Martin R. , Nisbet Euan G. , Michel Sylvia E. , Lan Xin , Dlugokencky Ed , Lowry David , Fisher Rebecca E. , France James L.
Published: March 2024

From 2020, the atmospheric methane burden has grown at the fastest rate in the detailed observational record. This rise has been accompanied by an unprecedented plunge in d13C(CH4). The causes of recent accelerated growth are as yet uncertain but the geographic spread of growth and the rapid isotopic plunge suggest strong rises in isotopically light emissions from both Tropical and Boreal wetlands. These emissions may be due to rising precipitation and temperatures in parts of the tropics, and by rising temperatures in northern Canada, Siberia, and Europe. Over the longer period since 2007, methane’s actual growth is comparable to methane’s growth in the ‘worst case’ very high baseline emission scenario RCP8.5 (8.5 W/m2 forcing increase relative to pre-industrial). If the recent trend were to continue for more than another decade it could make the 2°C target as hard to achieve as the 1.5°C target is now. Natural feedbacks to climate warming in wetlands need to be included in future modelling and should be incorporated in climate modelling projects such as CMIP7. Methane’s recent accelerated growth also has wide implications for climate negotiations as it reduces the permissible total anthropogenic greenhouse gas emissions if the Paris Agreement is to be achieved. Strong growth in non-anthropogenic methane emissions, driven by feedback impacts on natural and quasi-natural sources, was not expected in modelling at the time of the Paris Agreement and shows the urgency of improving our understanding of the feedback impacts of climate change. The simplest way to limit methane’s growth is for all nations,  including non-signatory countries, to cut anthropogenic emissions urgently and sharply, meeting or exceeding the targets of the Global Methane Pledge.
Identifying success factors for the recovery of Andean tropical forests using observational and experimental plots
Authors: Marín Franklin , Bauters Marijn , Báez Selene , Palomeque Ximena , Perring Michael , León-Yánez Susana , Verbeeck Hans
Published: March 2024

The Andean tropical forests (ATF) are a well-known biodiversity hotspot, and they provide numerous ecosystem services such as carbon storage and water regulation. However, human activities including establishing pastures, cultivating crops, and fires, have significantly reduced the area covered by tropical forests and altered their structure, composition, and function. To counter forest degradation, various active restoration programs have been conducted. However, there is limited understanding regarding what factors influence the success of Andean forest recovery. Using a network of observational and experimental plots, that allow an understanding of recovery pathways across time and over environmental conditions, we address the question: what are the driving factors influencing establishment success in reforestation efforts? We established 118 observational plots along different environmental conditions (e.g. climate and soil types), and 96 experimental plots across an elevation gradient in Ecuador. The observational plots were established in 18 different young reforested sites (5 -10 years) to assess carbon productivity. On the other hand, the experimental plots were installed at three elevations (2200, 2800, and 3200 m a.s.l.) to evaluate the effects of pasture competition and artificial shading, in a factorial design, on survival and growth rate of five native tree species. Our findings from the observational plots revealed that grazing exclusion, precipitation, planted species richness, and soil properties significantly influence carbon productivity in reforested sites. Preliminary results from the experimental plots revealed that the effect of grass competition and shade on seedling performance varied tremendously according to species and elevation. In summary, our results suggest that land management practices, planted species richness and species type, and climate conditions are determining factors in regard to successful forest recovery.
Digital thermal 3D model for thermal comfort analysis at district scale.
Authors: Delasse Chaimaa , Hajji Rafika , Landes Tania , Macher Hélène , Kastendeuch Pierre , Najjar Georges
Published: March 2024

Today’s cities face many challenges, including those related to climate change, energy efficiency, and human well-being. These issues are closely linked to the thermal dynamics of the built environment. Sub-optimal solutions and increased vulnerability often result from a lack of deep understanding of the spatial and temporal variations of thermal interactions in the urban context, particularly in data-limited regions. The primary objective of this thesis is to develop a methodology for creating "as-built" digital thermal models through 3D reconstruction of urban scene objects such as buildings, trees, and pavements. The coupling of 3D geometry and TIR (Thermal Infra-Red) acquisitions at different periods enhances the semantic richness of the model and facilitates the study of building-tree thermal interactions. This, in turn, enables the calculation and the monitoring of the evolution of thermal comfort indices at a micro-scale (
Role of buttressing in the dynamic response to Western Antarctic Peninsula ice shelf collapse
Authors: Wagner Luisa , Rückamp Martin , Fürst Johannes
Published: March 2024

Ice shelves on the western Antarctic Peninsula have partially or completely disappeared due to widespread thinning and retreat. The loss of floating ice results in a reduction of the buttressing on the upstream grounded ice body. As a consequence, tributary glaciers are accelerating and retreating further, leading to increased ice discharge and, in turn, an increased contribution to sea-level rise. Improving projections of the rate of sea-level rise from the area demands an in-depth understanding of the current mechanisms at play.In order to gain this, we aim to quantify and characterise the buttressing effect of the ice shelves. To achieve this, we model hypothetical upper-end scenarios by either an immediate complete collapse of all floating ice or a sustained extreme melting. The main focus here is on the stability of the tributary glaciers and the ability of the ice shelf to rebuild itself.To run the scenarios, we operate ISSM based on surface and basal topography from BedMachine and MEaSURE velocities. A Shallow-Shelf-Approximation with Budd and Weertman sliding laws, Beckmann and Goosse basal forcing parameterisation and von Mises calving is used. To initialise the retreat scenarios, we determine the basal friction coefficient of the grounded area and the ice shelf rheology using a joint inversion technique with regularisation.
High-resolution 4D GPR data acquisition strategy to monitor fast and small-scale subsurface flow processes
Authors: Stephan Sophie , Jackisch Conrad , Tronicke Jens , Allroggen Niklas
Published: March 2024

High-resolution measurement techniques for distributed and fast soil water dynamics could advance the understanding of subsurface infiltration processes on the plot scale when it can combine high spatial and temporal resolution with a high repeatability of the measured data.Ground-penetrating radar (GPR) is a promising geophysical tool to image and quantify subsurface flow processes in a non-invasive fashion. In the literature, different strategies to collect time-lapse GPR data have been presented. However, so far, no standardized data acquisition and analysis strategy has been established to monitor subsurface changes related to water infiltration and to compare the outcomes of different experiments.Here, we present a 4D-GPR measurement strategy to monitor infiltration experiments by combining an irrigation pad (to simulate moderate rain fall events) with a manually operated 3D GPR measurement platform (equipped with a two-channel GPR antenna array and positioning guides). For investigating the repeatability and resolution limits of our measurement strategy, we conducted a systematic field experiment with two recurrent irrigations at two nearby spots at a selected field plot. Our results show that we can reliably monitor non-uniform subsurface flow processes with a spatial resolution < 5 cm and a temporal resolution below 10 minutes.Because of these so far unreached spatial and temporal resolution capabilities we consider our 4D-GPR measurement strategy as a first step toward a standardized strategy for monitoring infiltration processes. Furthermore, such detailed knowledge about the resolution and repeatability limits of 4D-GPR measurements opens new options for further interpretation approaches, for example without assumptions about a horizontally stratified subsurface model.
Eutrophication and deoxygenation of coastal waters: how to improve water quality? 
Authors: Slomp Caroline P.
Published: March 2024

Coastal waters worldwide are increasingly affected by oxygen loss due to human-induced eutrophication and global warming. This coastal deoxygenation has dramatically altered biogeochemical processes with major consequences for marine life. Prominent examples of large anthropogenic coastal “dead zones” include the Gulf of Mexico, Baltic Sea and Chesapeake Bay but numerous small coastal systems are also strongly affected. Many efforts are currently underway to restore the water quality of these coastal waters, but these are not always effective. In this presentation, I will discuss how the interplay of biogeochemical processes and hydrodynamics may affect present-day restoration efforts in coastal systems. Using examples from a range of field and modelling studies performed by my group, I will specifically discuss legacy effects resulting from accumulation of organic-rich sediments, the potential for reoxygenation of coastal waters through increased water column mixing and/or lateral water exchange and the expected short-term and long-term effects of nutrient load reductions. Taken together, our results highlight that there is no one-size-fits-all approach to rapidly improve water quality in coastal waters suffering from eutrophication and deoxygenation. 
Rapid field measurement of uranium in water samples 
Authors: Hegedűs-Csondor Katalin , Surbeck Heinz , Baják Petra , Mádl-Szőnyi Judit
Published: March 2024

We present an analytical method that allows for the rapid measurement of uranium in water samples. For a 50 ml sample concentrations down to about 2 micro-g/l can be measured within an hour. There are no toxic chemicals used and the whole equipment is portable and can be powered by a 12 V battery. The preparation consists of adding 200 mg silica gel to the 50 ml sample, stirring for 1 hour, filtering out the silica gel and transferring it to a semi-micro cuvette for the measurement. Several samples can be prepared in parallel, depening on the number of magnetic stirrers available. The measurement takes only 1 minute and uses the uranyl fluorescence, enhanced by the adsorption on silica gel. Excitation is done by a pulsed UV-LED at 285 nm. The delayed fluorescence signal around 520 nm is detected by a 6 mm x 6 mm Silicon Photomultiplie (SiPM) behind a 520 nm bandpass filter. Pulsing the LED, converting the SiPM output and displaying the result is controlled by an Arduino microprocessor. All details of the experimental setup as well the software code are presented. It's open source, open to be copied and the whole material costs are only around 500 Euro.
Post-fire restoration impacts on soil microbial communities in a Mediterranean region
Authors: Roncero Ramos Beatriz , Romero Montserrat , Plaza Álvarez Pedro Antonio Plaza Álvarez , Lucas-Borja Manuel Esteban , Muñoz-Rojas Miriam
Published: March 2024

Fire is a natural element of the landscape; however, it can also have serious effects on the environment. Although the effect of fire on plant communities has been broadly studied, we lack information on the effect of fire on soils. Several types of post-fire treatments have been applied in Mediterranean areas for soil protection and potential regeneration of soil fertility, i.e. logging or mulching. Yet, the effect of these treatments on the soil biodiversity are not fully understood. Here, using different soil physical and biological approaches methods, we analysed the impacts of different post-fire treatments on the composition and diversity of microbial communities (bacteria and fungi) in a Mediterranean forest. Our results showed substantial differences in the responses of the fungal community to the different post-fire treatments, i.e. straw mulching and salvage logging . Opposite, the soil bacterial community was not affected by the post-fire treatments. Overall, soil fungi were more sensitive than bacteria to fire, but the recovery of this taxa following the fire event was faster. Our results can provide useful information for restoration of fire-impacted areas in the Mediterranean region.
The impact of the ambient conditions and component’s part-load behaviour on the actual annual power output of CO2-Plume Geothermal (CPG) systems
Authors: Schifflechner Christopher , Spliethoff Hartmut
Published: March 2024

Subsurface reservoirs play an important role in decarbonizing the energy sector, be it through geothermal energy production or carbon capture and storage (CCS). In recent years, there has been an increasing interest in CO2-Plume Geothermal (CPG), which combines CCS with geothermal, using CO2 instead of water as a subsurface heat and pressure energy carrier. CO2 as a subsurface working fluid is more efficient as it has a higher mobility (inverse kinematic viscosity) and its large thermal expansion coefficient results in a thermosiphon effect that reduces the pumping power required. CO2 can also be directly utilized in a turbine for power generation. Furthermore, since CPG systems are added to full-scale CO2 Capture and Sequestration operations, all of the initially injected CO2 is ultimately stored. CPG therefore constitutes both CO2 Capture Utilization as well as Storage (i.e. CCUS).In recent years, CPG has experienced increasing interest from academia and industry. Several in-depth studies have assessed the impact of various parameters such as the geothermal gradient, wellbore diameter or reservoir permeability on the CPG performance. However, these studies have not evaluated the potentially significant impact of the varying ambient conditions on the CPG performance profile. The potential effect of the air temperature on the CPG performance has only been discussed in a paper by Adams and Kuehn (2012) and in a more recent work by van Brummen et al. (2022), but without considering the the off-design behaviour of the main components, such as the turbine or compressor. This contribution assesses and discusses how the CPG performance profile might vary across several geographical settings and how the design point of the CPG components affect their achievable net power outpt. Therefore, valuable insights regarding the most attractive settings for future CPG systems can be drawn.
Impact of Tropospheric Delay Correction on the Quality of Landslide Mapping in the Southern Central Andes, Northwestern Argentina
Authors: M.Aref Mohammad , Bookhagen Bodo , R. Strecker Manfred
Published: March 2024

Slow-moving landslides in high-mountain regions pose a significant natural hazard and are capable of delivering large sediment volumes to the fluvial system. Time series analysis of Interferometric Synthetic Aperture Radar (InSAR) allows us to identify unstable and potentially dangerous areas prone to landsliding, but this technique also helps quantify seasonal dynamics for predicting landslide behavior.Our study in the Eastern Cordillera of the Argentine Andes focuses on enhancing InSAR's reliability for landslide mapping. This region is characterized by moisture changes along the topographic gradient across the orogen and seasonal variability associated with the South American Summer Monsoon. We extract InSAR time series data from Sentinel-1A/B's C-band (2014-2022) and ALOS1 PALSAR's L-band (2006-2011). Tropospheric delay is caused by atmospheric turbulence and vertical stratification changes. These delays can introduce significant errors in deformation measurements, thus impacting the quality of maps portraying landslide deformation rates. To address this problem, we apply various correction techniques, ranging from spatial and temporal filtering to water-vapor estimation from an atmospheric model. Fading signal noise, another challenge caused by multi-looking and short temporal baselines in the Small Baseline Subset (SBAS) technique, additionally compromises InSAR time series accuracy. We investigate the pattern and magnitude of fading signals in landslide areas using Small Baseline Subset (SBAS) with different neighboring connections and non-linear phase inversion methods, such as the Eigenvalue Decomposition-based Maximum Likelihood (EMI), Eigenvalue Decomposition (EVD), and the Phase Triangulation Algorithm (PTA).Our research evaluates both statistical methods and Global Atmospheric Models for correcting tropospheric delays and fading signal noise. We explore statistical methods, such as double-difference filtering and corrections based on phase elevation, for different spatial windows, including individual catchments, moving windows, and adaptive window sizes. The efficiency of these methods varies with the environmental and topographic conditions in the orogen. Both stratified and turbulent components of the troposphere, along with fading signal noise, can significantly influence tropospheric delay and time series quality. In the context of the factors that influence deformation signals and the combined array of methods to obtain robust measurements, we can identify the spatial and temporal characteristics of slow-moving landslides and assess the different impacts on rate changes.
Post-seismic analysis of the Kahramanmaraş triple junction using GNSS data acquired following the 2023 Kahramanmaraş earthquakes
Authors: Özbey Volkan , Henry Pierre , Özeren Mehmet Sinan , Klein Elliot C. , Haines Alan John , Wang Lifeng , Friedrich Anke Maria , Şengör Ali Mehmet Celal
Published: March 2024

Understanding the evolution of the crustal kinematic/dynamic response of the Kahramanmaraş triple junction after the occurrence of the destructive earthquake doublet on 6 February 2023 is of great interest to seismologists and geodesists. Along with the near-field postseismic effects such as the afterslip, it is also essential to study relatively far-field effects where the interaction of the brittle upper crust with the lower crust and upper mantle can be relevant in how the stress is redistirbuted during the months/years following the earthquake. The latter seems to be a particularly interesting problem for this case because the earthquake perturbation to the interseismic velocity field is very significant and extends approximately 400 km to the west of the rupture zone.  The affected region seemingly comprises a large part of the Central Anatolian Block where the interseismic internal deformation was less than 10 nanostrain/yr prior to the large event. Most tomographic studies show that the lithospheric mantle beneath Central Anatolia is either very thin or absent. This indicates a necessity to test various upper mantle and lower crust viscosity scenarios for the far-field effects.We conducted a GNSS (Global Navigation Satellite System) campaign in July 2023, reoccupying 18 sites around the triple junction area to monitor the intermediate and far-field post-seismic effects caused by the ruptures and the subsequent loading behavior of the faults therein. Our primary aim was to characterize: (1) the postseismic effect on the relatively far-field, which likely includes viscoelastic responses in central Anatolia where the lower crust and mantle are presumably weak; (2) variations of the strain field stemming from aftershocks of the large earthquakes; and (3) the response of secondary faults such as the Ecemiş, Deliler, and Sariz faults in Adana and Kayseri provinces. 1-year GNSS time series of continuous stations broadly reveal the postseismic field behavior. The occurence of a postseismic signal is clear northwest of the rupture zone however, the signal is weak for the stations southwest of the earthquake area. The preliminary analysis of the survey mode sites is in agreement with continuous stations. Here we present the resulting post-seismic velocity, the strain rate field and its contrast from the pre-event strain rate field and a preliminary viscoelastic model to shed light onto the underlying physical processes.
GlobalRx: A global assemblage of regional prescribed fire records for use in assessments of climate change impacts
Authors: Hsu Alice , Thurgood Jane , Smith Adam , Anderson Liana , Clarke Hamish , Doerr Stefan , Fernandes Paulo , Kolden Crystal , Santín Cristina , Strydom Tercia , Jones Matthew ,   GlobalRx Consortium
Published: March 2024

Prescribed (Rx) and controlled fires are an important land management tool used globally for a variety of reasons, including the reduction of hazardous fuel loads, ecological conservation, agriculture, and natural resource management. Its use has important implications for wildfire risk, biodiversity, and carbon storage. However, the use of Rx and controlled fires is highly dependent upon weather conditions, requiring a weather window during which a careful balance of temperature, moisture, and wind ensure that the burns achieve their objectives while minimizing ecological damage or risk to human lives or assets. The planning and execution of Rx burns must also consider how these weather conditions interact with the local vegetation and ecology. As fire weather is projected to grow more extreme under the impacts of climate change, there is a growing need to monitor this effect on the ability to carry out Rx burning.Here, we introduce a new dataset, GlobalRx, which includes around 140,000 records of Rx and other controlled fires from 16 countries, encompassing 207 ecoregions and 13 biomes around the world. For each record, we have geolocated values of various metrics of fire weather and fire danger (e.g. fire weather indices, vapour pressure deficit) from the ERA5 meteorological reanalysis, as well as the biome, ecoregion, fuelbed type, and protected area status from global thematic layers. We demonstrate the usefulness of this dataset for analyzing viable meteorological windows under which Rx fires may be conducted across diverse environmental settings in the present climate, as well as how these Rx burning windows may shift under the threats of climate change. This dataset has potential to shed light on how Rx burning windows may shift under future climate change, as well as opportunities to understand other drivers and effects of Rx burning.This project has been supported by valuable contributions from non-public data from a consortium of data providers: Parks Canada, South Africa National Parks, Brazilian Institute of the Environment and Renewable Natural Resources, East-Pyrenees Prescribed Burning Team, Institute for Nature Conservation and Forests (Portugal), Regional Forest Fire Service (Italy), Russian Federal Forestry Agency, H2020 LifeTaiga Project, Government of the Principality of Asturias, Council of Andalucía, Council of Galicia, Forestry England, National Forestry Commission of Mexico, ZEBRIS Geo-IT GmbH, Hokkaido University, Pau Costa Foundation, Asian Forest Cooperation Organization.