bluuebunny/crossref_metadata_2025 huggingface dataset:
Relation between the distribution of fuel types and forest fires in Austria
Authors: Silva Andrade Mariana , M. Müller Mortimer , Kuhnen Katrin , Vacik Harald
Published: March 2024

The altering climate patterns contribute to variations in precipitation, temperature and overall ecosystem conditions, influencing the composition and combustibility of forest fuels in the alpine regions. Changes in vegetation patterns, with shifts in species distribution and the prevalence of dry, flammable materials, increases the risk through wildfires. Rising temperatures and prolonged periods of drought enhance the likelihood of ignition and intensify fire behavior. Thus, this research aims to carry out a comprehensive vegetation analysis to characterize the different fuel types in Austria and to provide the scientific basis for developing a detailed forest fuel map, considering various types of vegetation, topography and land cover. We use statistical models to predict fuel characteristics based on vegetation type and empirical data collected during field surveys in the recent years. The spatial distribution of fuel types will be related to an analysis of the location of historical fire data for the time period 2001-2023. A statistical analysis is done to identify clusters, patterns, and relationships for different fuel types. This integrated methodology not only enriches our understanding of the complex interconnection between vegetation fire ignition and behavior, but also provides the scientific basis for developing targeted strategies in forest fire management and improving prevention measures in Austria.
Luminescence rock surface dating of englacial transported debris from Mer de Glace glacier, French Alps
Authors: Rodari Léa , Margirier Audrey , King Georgina , Rowan Ann , Schmidt Christoph , Jouvet Guillaume
Published: March 2024

Significant mass loss and increased rock debris cover have been observed across many mountain glaciers due to climate change. However, the dynamics of sediment transport through alpine glaciers are not fully understood and should be investigated to better constrain the future evolution of mountain glaciers under a changing climate. Englacial sediment transport is difficult to observe and to that end, we quantify the englacial transport time of debris within a glacier using a novel method combining luminescence rock surface burial dating and ice-flow modelling. Our study focuses on Mer de Glace, Mont Blanc Massif, French Alps, where supraglacial debris has expanded over the past 20 years.We collected near-surface rock debris (4–22 cm in diameter) of granite from the ablation area of Mer de Glace that we expect to have experienced different englacial transport durations. Under subdued red light, we cored the samples perpendicular to their surfaces and sliced the cores into ~1 mm discs for luminescence dating. We first evaluated whether the luminescence signals had been well bleached prior to deposition by measuring the evolution of luminescence signals with depth throughout the core (i.e. measurement of the bleaching plateau). We used a protocol comprising infra-red stimulation at 50 °C and 225 °C, followed by blue stimulation at 125 °C to explore the signals of different minerals with different luminescence properties. Of the 29 samples investigated, 20 were well bleached, exhibiting a clear plateau in luminescence signals with depth (following the approach of Rades et al., 2018). We are currently using a single-aliquot regenerative dose protocol to date the rock surfaces of these samples to obtain englacial transport durations. In the next step, we will contrast the englacial transport durations measured using luminescence with those predicted using the ice-flow model IGM (Jouvet et al., 2022), allowing us to better understand the dynamics of mountain glaciers over centennial to millennial time scales. ReferencesJouvet, G., Cordonnier, G., Kim, B., Lüthi, M., Vieli, A., & Aschwanden, A. (2022). Deep learning speeds up ice flow modelling by several orders of magnitude. Journal of Glaciology, 68(270), 651-664.Rades, E. F., Sohbati, R., Lüthgens, C., Jain, M., & Murray, A. S. (2018). First luminescence-depth profiles from boulders from moraine deposits: Insights into glaciation chronology and transport dynamics in Malta valley, Austria. Radiation Measurements, 120, 281-289.
Patterns in GRACE-FO LRI Post-Fit Range Rate Residuals
Authors: Duwe Mathias , Koch Igor , Flury Jakob
Published: March 2024

The LRI on GRACE Follow-On (GRACE-FO) provided range and range rate measurements for more than 4 years. At our institute we produce monthly gravity field coefficients from these observation data. We apply different techniques to analyse the post-fit range rate residuals and the post-fit range acceleration residuals to identify unknown characteristics and systematic effects within the LRI measurement system. We identified several effect: the range rate effect, the panel effect, the CNR effect and the polar effect. All these effects have not been detected in the KBR residuals. Beside the current status of GRACE/GRACE-FO processing standards at our institute, the focus lies on the characterisation of the range rate effect as well as the panel effect. The range rate effect occurs when the range rate observation is around 0 m/s and shows a very specific butterfly pattern. The panel effect is induced by the interaction of the spacecraft body panels and the sun. There is also an interaction of the LRI steering mirrors observable when the LRI laser beam is aligned with the sun.
Analysis of the use of actual evapotranspiration calculated with Landsat imagery and climate forecasts, assessed with an agrohydrologic model for irrigation scheduling in fruit crops
Authors: Jiménez Bello Miguel Angel , Carricondo-Antón Juan Manuel , García-Prats Alberto , López-Pérez Esther , Manzano-Juarez Juan , Pulido-Velazquez Manuel , Martínez-Alzamora Fernando
Published: March 2024

The evapotranspiration of vegetation (ET) is a key component of the hydrological balance. Various tools and models have been proposed to estimate evapotranspiration in fruit crops. Among them, the most widely used approach is that proposed by the Food and Agriculture Organization (FAO), which considers climatic variables included in reference evapotranspiration (ETo), as well as the type of crop and its characteristics represented by a single crop coefficient (Kc). However, there is evidence that in tall and discontinuous canopies, such as citrus orchards, with a high degree of interaction with the environment, Kc can change depending on local environmental conditions and the amount of vegetation.Other methods, such as measurements of stem water potential, sap flow sensors, and moisture probes, allow for determining the water status of the crop, but only for a limited number of trees, and uncertainties arise when extrapolating values. Remote sensing fills this gap if spatial and temporal resolutions suit the monitored crop. A successful approach in water management is using models that calculate latent heat as a residue of the surface energy balance (SEB).This study applied an energy balance to calculate ET in an irrigation district. The study site is located in the Valencia region (Spain; 39º22'43'' N, 0º28'20'' W) with localized irrigation, where most crops are citrus. A total of 182 images from the Landsat satellite constellation for the period 2013-2018 were used to estimate instantaneous ET by extrapolating daily actual ET (ETSEBAL) values using climatic data.These climatic data correspond to predictions the Global Forecast System (GFS) provides. This way, climatic predictions are used for scheduling instead of the classical methodology that uses past data to estimate evapotranspiration. The study's objective is to analyze the results using a dynamic Kc obtained from the actual state of the crops and climatic predictions for each plot, compared to a generic Kc obtained for standard conditions and past climatic data.The results suggest that, for the studied plots, the relationship between drained water and the actual volume provided by irrigators would be reduced by 20% to -30 %. A point agrohydrological model calibrated with capacitive moisture probes was used to monitor soil water balance.In the same way, the methodology allows for determining the stress level of crops and maintaining it within recommended limits.
Geomorphological record of a former ice stream to ice shelf lateral transition zone in Northeast Greenland
Authors: Lane Timothy , Darvill Christopher , Rea Brice , Bentley Mike , Smith James , Jamieson Stewart , Ó Cofaigh Colm , Roberts David
Published: March 2024

Understanding ice stream dynamics over decadal to millennial timescales is crucial for improving numerical model projections of ice sheet behaviour and future ice loss. Here, we document the terrestrial deglacial landsystem of Nioghalvfjerdsfjorden Glacier (79N) in Northeast Greenland following the Last Glacial Maximum, and the lateral transition of that margin to a floating ice shelf. High-elevation areas are influenced by local ice caps and display autochthonous to allochthonous blockfields that mark the interaction of local ice caps with the ice stream below. Below ~600 m a.s.l. glacially abraded bedrock surfaces and assemblages of lateral moraines, ‘hummocky’ moraine, fluted terrain, and ice-contact deltas record the former presence of warm-based ice and thinning of the grounded ice stream margin through time. In the outer fjord a range of landforms such as ice shelf moraines, dead-ice topography, and weakly developed ice marginal glaciofluvial outwash was produced by an ice shelf during deglaciation. Along the mid- and inner-fjord areas this ice shelf signal is absent, suggesting ice shelf disintegration prior to grounding line retreat under tidewater conditions. However, below the marine limit, the geomorphological record along the fjord indicates the expansion of the 79N ice shelf during the Neoglacial, which culminated in the Little Ice Age. This has been followed by 20th Century recession, with the development of a suite of compressional ice shelf moraines, ice-marginal fluvioglacial corridors, kame terraces, dead-ice terrain, and crevasse infill ridges. These mark rapid ice shelf thinning and typify the present-day ice shelf landsystem in a warming climate.
 A Deep Learning Approach for Improving Soil Property Prediction with Unannotated Hyperspectral DESIS Imagery
Authors: Bishop Thomas , Hu Kun , Filippi Patrick , Wang Zhiyong
Published: March 2024

An increasing number of hyperspectral satellite platforms are becoming available as exemplified by the DESIS platform.  This generates an immense amount of spectral information about the earths surface which is unlabelled.  In this work we use DESIS imagery to compare two deep learning approaches for utilising all of this unlabelled data for predicting topsoil properties. The first is transfer learning from laboratory based spectral libraries.  The second is a novel self-supervise learning approach which employs a transfer-based autoencoder architecture for unsupervised learning, analyzing spectra patterns and cultivating powerful latent representations for the downstream task of soil property analysis. Using a dataset from eastern Australia we show that the self-supervised learning approach gives superior predictions than transfer learning.
Extreme events in a templex
Authors: Charó Gisela Daniela , Faranda Davide , Ghil Michael , Sciamarella Denisse
Published: March 2024

Theoretical and numerical studies have shown that transient atmospheric motions leading to weather extremes can be classified through the instantaneous dimension and stability of a state of a dynamical system [Faranda et al., Sci. Rep., 2017]. The asymptotic values of these quantities can be computed theoretically only for specific systems, while their numerical counterpart for climate observables provides information on the rarity, predictability, and persistence of specific states. In this work, we present a first attempt to relate the presence of extreme events with the elements that make up a templex of the system under study, both in the deterministic [Charó et al., Chaos, 2022] and stochastic frameworks [Charó et al., Chaos, 2023]. The templex provides the key characteristics of the topological structure underlying a dynamical system. This work will present results for the classical, deterministic Lorenz [JAS, 1963] attractor and for the Lorenz Random Attractor, dubbed LORA [Ghil & Sciamarella, NPG, 2023].
Ground-penetrating radar can ascertain the influence of biochar on soil wetting
Authors: Galagedara Lakshman , Pathirana Sashini , Krishnapillai Manokararajah
Published: March 2024

Incorporating biochar (BC) as a soil amendment has become a prominent agricultural management practice since it has many advantages. Most soils amended with BC have shown improvements in soil physical and hydraulic properties, including bulk density, soil porosity, water retention, field capacity, and permanent wilting point. Ground-penetrating radar (GPR) is a non-destructive geophysical technique that is used to study soil properties and state variables. Yet, there is a lack of research studying the influence of amendments on soil hydrology using GPR.  Therefore, this study was aimed at evaluating the ability of GPR in assessing the effect of BC on soil hydrology. The experiment was conducted under laboratory conditions using plastic containers measuring 28.6 cm in length, 20 cm in width and 16.4 cm in height. These plastic containers were filled up to 14 cm height with three different treatments (T); T1 (100% Sand+0% BC), T2 (99.5% Sand+0.5% BC), and T3 (98% Sand+2% BC) on a mass basis. Soil moisture sensors were placed horizontally at 2, 7, and 12 cm depths while packing the containers. The GPR data were collected using 1000 MHz center frequency transducers by keeping transmitter and receiver on opposite sides of the container (zero-offset profiling survey) at 20 cm antenna offset. Data were collected before, during, and after the wetting process over a one-hour timeframe. A 204 mL of water was applied every 4 min (13 times) to increase the soil water content at each time by 2% from initial water content. The GPR data were processed, and radargrams were prepared to observe the wetting front movement. Soil water contents were estimated utilizing the travel time of the GPR direct wave through the treatment media. GPR travel time and moisture sensor data were compared in each treatment. The GPR estimated soil water contents correlated well with moisture sensor data (correlation coefficient (r)>0.93) in all three treatments. Results have shown that the travel time of GPR direct wave responded differently for three treatments. The rate of change in GPR estimated soil water content over time exhibits an increase with the percentage of BC (T1
Refinement of tomographic models in the Western Mediterranean region through full waveform inversion
Authors: Herrero-Barbero Paula , Schimmel Martin , Martí David , Krischer Lion , Carbonell Ramon
Published: March 2024

Accurate imaging of crustal structures necessitates sophisticated inverse modeling utilizing extensive waveform data, including high-frequency signals from minor seismic events, an aspect traditionally underused in full waveform inversion (FWI). Integrating these intricate elements into novel tomographic models using FWI for the Western Mediterranean region, we address the challenge of enhancing model resolution while acknowledging the increased computational demands associated with inversion, an endeavor made feasible only through High-Performance Computing (HPC).This study incorporates new considerations by comparing diverse reference models and updating a substantial dataset of earthquakes spanning the time interval from 2007 to 2022. While station deployment in the Mediterranean region is notably dense, the uneven geographical distribution of ray coverage from far-field waveforms necessitates the inclusion of lower magnitude earthquakes (M
The dark zone of an alpine glacier - considering albedo impacts of firn loss
Authors: Hartl Lea , Stocker-Waldhuber Martin , Covi Federico , Baldo Anna , Naegeli Kathrin
Published: March 2024

As the decline of alpine glaciers continues and accelerates, many glaciers are losing their firn area. Former accumulation zones are increasingly seeing melt conditions and mass loss. The loss of brighter snow and firn surfaces lowers albedo locally and at the glacier scale, impacting surface energy balance and leading to an albedo-mass balance feedback effect.We assess the recent progression of firn loss into the (former) accumulation zone of Gepatschferner, Austria, focusing particularly on ice surfaces that have newly become exposed. Broadband albedo in the visible and near-infrared generally shows an altitudinal gradient in early summer from the darker, bare-ice glacier tongue to the snow covered region at higher elevations. As the melt season progresses and ablation of multi-year firn at higher elevations begins, albedo decreases substantially in areas that lose their firn cover. We find that these areas can become darker than ice in the ablation zone where no firn was present in previous years. In the extreme summer of 2022, the glacier surface of Gepatschferner was darkest in parts of the former accumulation zone where the firn-line shifted upwards. Newly exposed ice surfaces formed a “dark zone” between the remaining firn and previously exposed bare-ice areas. This zone of minimal albedo at relatively high elevations of the glacier persisted until the first snow falls in autumn and reemerged during the 2023 ablation season. Time series of satellite imagery show melt patterns as well as trends and variability of homogenized broadband albedo in the study region. In addition to remote-sensing based observations, multiple in-situ datasets are available for the summit region of Gepatschferner (i.e. on-ice weather station, ablation stakes, automatic camera, ice thickness measurements). Combining these datasets provides a unique opportunity to explore the impact of firn loss and albedo decrease on energy and mass balance, generate calibration and validation data for point scale and distributed modeling, and generally improve understanding of processes related to firn loss at different spatial and temporal scales. However, each observational dataset comes with uncertainties related to the scale and method of observation and the parameter being observed. Leveraging the potential of the rich available data basis requires careful consideration of the characteristics of the different data types and, when combined with energy and mass balance modeling approaches, the forcing requirements of the model. We present preliminary results from a project addressing the above for Gepatschferner and hope to connect with the community regarding the observation, modeling, and impacts of darkening mountain glaciers.
X-ray and Raman spectroscopy of jarosite and ammoniojarosite from several terrestrial localities
Authors: Bushmaker Simon , Nachlas William , Bonamici Chloë
Published: March 2024

Jarosite, a hydrous K-rich sulfate mineral, was found in fine-grain quantities on the Martian surface by the Opportunity rover in 2004. Jarosite found in some terrestrial settings can form a complete solid solution with ammoniojarosite through substitution of the ammonium ion (NH4+) which replaces K+ within its crystal structure. Requiring water and acidic conditions to form, jarosite stands as a potential indicator of ancient N-bearing environments on the Martian surface. The Mars Perseverance rover is currently exploring the Martian surface with analytical instrumentation that may be capable of detecting N-rich jarosite, including the SHERLOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals) and the PIXL (Planetary Instrument for X-ray Lithochemistry) detectors. To investigate the detection of N in jarosite with Raman and X-ray spectroscopy, we analyzed several terrestrial samples of jarosite and ammoniojarosite using laser Raman spectroscopy and electron-excited Wavelength Dispersive X-ray Spectroscopy (WDS). Comparison of high wavenumber regions of Raman spectra with WDS spectra of N K-α X-rays on the same samples will be used to investigate detection and quantification of N as ammonium in jarosite.
Enhancing soil carbon sequestration in the parks of the city of Barcelona 
Authors: Poblador Sílvia , Álvarez Lucía , Díaz Bárbara , Felip Marc , Sabater Francesc , Vienne Arthur , Vicca Sara
Published: March 2024

Climate change is progressing at an alarming pace. In order to limit global warming to the agreed-upon 2°C in the United Nations Paris Agreement, we require both rapid decarbonization and the implementation of negative emissions technologies (NETs), that actively remove carbon dioxide (CO2) from the atmosphere and ensure stable long-term carbon storage. In this context, enhanced silicate weathering (ESW) has been proposed as a NET based on a nature solution. ESW aims to accelerate the natural uptake of atmospheric CO2 during the weathering of silicate rocks by grinding them, increasing their reactive surface and speeding up the process. This NET is particularly interesting as it does not compete for space with other economical activities. For instance, in agroecosystems, ESW is already considered a promising NET, offering multiple co-benefits for crop production when spreading silicate minerals on arable soils (i.e. increase in crop yields, restoration of soil base cations and micro- and macronutrient stocks). Besides agricultural land, urban soils can also be suitable for ESW. The application of ESW in city parcs and gardens presents an opportunity to increase the capture of atmospheric CO2, while also favoring vegetation growth (lawn, shrubs and flowers) and potentially enhancing resistance to drought and pests.EMBARCARB is a pilot project that aims to increase soil carbon sequestration and improve the vegetation status in two parcs of the city of Barcelona (SE Iberian Peninsula), during an extremely dry year. Moreover, the project also aims to compare the carbon sequestration capacity of soils with weathering of silicate rocks and concrete demolition fines, thus reusing construction debris and strengthening the circular economy of the region. Here, we explore the preliminary results of the project and give a first estimation of the weathering rates and the capacity of such NETs to enhance soil carbon sequestration in the green areas of the cities.
Resistant high tree cover mode with increasing fire in Indonesian natural peatland ecosystems
Authors: Diatmiko Eufrasia B. A. , Rietkerk Max , Staal Arie
Published: March 2024

The vulnerability of tropical ecosystems to global changes is a growing concern, with tree cover distribution patterns playing a pivotal role in their responses to changing environmental conditions. It is important to understand how natural ecosystems respond to these changes to assess the resilience of the ecosystems. While extensive research has investigated tree cover distributions in the tropics, a notable gap exists in understanding the effects of environmental variables to tree cover and the underlying mechanisms in Indonesian natural ecosystems, with its vast peatland areas. In response to this gap, we analyze the relative importance of environmental variables, specifically precipitation and fire, on shaping tree cover distributions in peatland and non-peatland ecosystems in Indonesia. We use the Global Forest Change dataset on tree cover with the spatial resolution of 30 meters. To focus on natural ecosystems, we filter out areas with human intervention. We find a consistent unimodal distribution of tree cover in the gradients of fire frequency and precipitation, marked by a distinct peak in each value range of the variables. In non-peatland, we observe a switch from high to low tree cover mode with increasing fire, which occurs at intermediate fire frequency. In contrast, peatland ecosystems show a remarkable resistance of the high tree cover mode despite increasing fire incidents. This implies that peatland could be more resistant to the same intermediate fire frequency than non-peatland. Our findings are relevant for ecosystem resistance in Indonesian peatlands and non-peatlands and their potential vulnerability to disturbances, particularly in the face of ongoing global environmental changes.
The increased likelihood of plankton community changes following marine heatwaves
Authors: Deeley Ryan , Grafke Tobias , Feudel Ulrike
Published: March 2024

When modelling any climatic system, it is important to carefully consider the relation between the many timescales that govern its evolution, since a certain change in their interplay can drastically affect the likelihood of observing critical transitions to distinct environmental regimes. In this study, we present how the onset of marine heatwaves - that are responsible for inducing prolonged periods of positive temperature fluctuations - can weaken state-based resilience leading to noise-induced shifts between species’ concentration levels in plankton communities. This is shown in a modified Truscott-Brindley model, a stochastically forced fast-slow system that encapsulates the interaction between phytoplankton and zooplankton species during red tide events in marine environments. Deterministically, the system can be bistable, possessing stable states with high and low phytoplankton biomass, or in an excitable monostable regime, where phytoplankton blooms form following perturbations. Environmental perturbations to the (temperature-dependent) species’ growth rates are modelled using multiplicative noise terms, namely Ornstein-Uhlenbeck processes with a correlation time parameter τ. During marine heatwaves, the correlation time τ of the external perturbations will increase. With ensemble Monte Carlo simulations of phytoplankton collapses, we demonstrate how mean first-exit times from the domain of attraction scale as the noise intensity weakens, across different prescribed values for the correlation time τ. These results yield numerical approximations for the systems’ quasipotential barrier heights - a concept from Freidlin and Wentzell’s theory of large deviations that quantifies resistance to noise-induced escape from a given domain - which elucidates a non-monotonic relation between the system vulnerability to critical transitions and the correlation time τ of the external perturbations. Indeed, initially there is a notable drop in system resilience as the correlation time τ grows from zero, although as τ increases further beyond a critical value, the system resilience begins to then increase. This non-monotonic relation is also reflected in the action values of most probable transition paths for escaping the domain of attraction, found using an augmented Lagrangian method to overcome the degenerate noise present in the system. These findings are compared and contrasted with results from other studies exploring how climate tipping points, or stochastic escapes from a domain of attraction, depend on the correlation time of the external perturbations. Finally, we consider candidate time-series for correlation times constructed from temperature records for the North Sea across periods including anomalously high values, and discuss whether - subject to these - varying system vulnerability to critical transitions is more sensitive to the rate of emergence or duration of the marine heatwaves.
Overview of water retention and suction stress properties of layered pyroclastic ashes in landslide prone areas of Campania, southern Italy
Authors: Roman Quintero Daniel Camilo , Damiano Emilia , Olivares Lucio , Greco Roberto
Published: March 2024

The loose, stratified composition of pyroclastic soil covers typically consists of layers of air-fall ashes and pumices. When these deposits are resting on steep slopes, they pose a significant geohazard due to slope instabilities. This scenario is evident in the carbonate massifs covered by pyroclastic soils in Campania (southern Italy), an extensive area of about 400 km2 prone to landslides. In these porous deposits, the soil suction in unsaturated conditions plays a crucial role in enhancing the slope stability by providing additional shear strength.This study aims to present a comprehensive overview of the hydraulic and shear strength characteristics observed in different layers of pyroclastic ashes across various sites in the Campania study area. By gathering datasets from previous studies and introducing new experimental data, the relationship between soil index, hydraulic properties and the shear strength in unsaturated conditions is examined.The findings highlight notable differences in hydraulic properties of soils originating from the same location but belonging to different layers: ashes from intermediate layers within the soil profile, where failure surface usually occurs; weathered ashes in direct contact with the carbonate bedrock, responsible of water exchange with deeper systems. The water retention curves of intermediate ashes exhibit air entry values at approximately 4 kPa, while those in contact with the bedrock show values around 25 kPa. Conversely, soils from the same layer but from different sites exhibit relatively similar hydraulic characteristics. For example, intermediate ashes from the same layer typically display air entry values varying between 0.5 kPa and 4 kPa. The same behavior also appears regarding the influence of soil suction on the shear strength of the investigated materials, which can be estimated directly from the water retention curves.
Lagrangian Coherent Structure regimes in the Baltic Sea and impact on algal blooms
Authors: Antivachis Dimitrios , Döös Kristofer , Axell Lars , Arneborg Lars , Koszalka Inga Monika
Published: March 2024

Algal blooms are common in the Baltic Sea during the summer, where they pose a significant threat to coastal services and industries. Lagrangian Coherent Structures (LCS) have been shown to play an important role in driving the mixing and transport of water masses and tracers in other ocean basins, such as the Mediterranean Sea (Antivachis et al. 2023), and are thus expected to have a strong effect on transport processes and the development and spread of algal blooms in the Baltic Sea.In this work, we use trajectory-derived Largangian diagnostics to investigate the distribution and variability of LCS in the Baltic Sea, using a series of 10-day trajectory experiments during summer 2022. Finite Size Lyapunov Exponent (FSLE), Trajectory Rotation Angle (TRA) and related metrics areused to assess the impact of LCS on horizontal mixing and dispersion processes in the basin. The potential influence of LCS on the spread and impact of algal blooms by opening/closing off transport pathways and exposing/shielding coastal regions is investigated by relating the spatiotemporal distribution of LCS to surface cyanobacteria concentrations obtained from satellite observations. The LCS regime in the Baltic Sea is compared to the ones observed in the Mediterranean in the author’s previous work (Antivachis et al. 2023). This is the first study to map the LCSs of the Baltic Sea and investigate their impact on algal blooms in that basin.This work is part of the ongoing ALGOTL project, funded by the Swedish research council for sustainable development (FORMAS), aiming to develop a Lagrangian modelling and forecasting framework for algae growth and dispersion for assessing the risk posed by algal blooms. Particle advection is carried out using velocity fields from the Swedish Hydrological and Meteorological Institute (SMHI) NEMO-Nordic configuration (Hordoir et al. 2019) and the TRACMASS Lagrangian trajectory code (Aldama-Campino et al. 2020).ReferencesDimitrios Antivachis, Vassilios Vervatis, and Sarantis Sofianos. Lagrangian coherent structures in the mediterranean sea: Seasonality and basin regimes. Progress in Oceanography, 215:103051, 2023. https://doi.org/10.1016/j.pocean.2023.103051Hordoir, R., Axell, L., Höglund, A., Dieterich, C., Fransner, F., Gröger, M., Liu, Y., Pemberton, P., Schimanke, S., Andersson, H., Ljungemyr, P., Nygren, P., Falahat, S., Nord, A., Jönsson, A., Lake, I., Döös, K., Hieronymus, M., Dietze, H., Löptien, U., Kuznetsov, I., Westerlund, A., Tuomi, L., and Haapala, J.: Nemo-Nordic 1.0: a NEMO-based ocean model for the Baltic and North seas – research and operational applications, Geosci. Model Dev., 12, 363–386, https://doi.org/10.5194/gmd-12-363-2019, 2019. Aldama-Campino, Aitor, Döös, Kristofer, Kjellsson, Joakim, & Jönsson, Bror. (2020, December 17). TRACMASS: Formal release of version 7.0 (Version v7.0-beta). Zenodo. http://doi.org/10.5281/zenodo.433792
Long-term Monitoring of Environmental and Geophysical Impacts in Conflict-Endured Zones: A Landscape Perspective on Kivu Lake
Authors: Lizaga Ivan , Latorre Borja , Bagalwa Montfort , Nkuba Bossissi , Bodé Samuel , Katcho Karume , Ciraba Honoré , Evrard Olivier , Büscher Karen , Vlassenroot Koen , Van Oost Kristof , Blake William , Navas Ana , Boeckx Pascal
Published: March 2024

Human displacements, especially those driven by violent conflicts forcing sudden population migrations, wield profound and enduring impacts on landscapes, instigating substantial disruptions to the natural environment. Beyond immediate destruction, these consequences pose challenges to ecosystem health, food security, and biodiversity conservation, particularly exacerbated in the absence of effective governance. Traditional land management practices, agriculture, and conservation efforts are disrupted, constraining the implementation of long or medium-term conservation practices in agriculture. These disruptions may contribute to increased erosion and sediment transport, depleting soil nutrients and resulting in natural disasters such as flash floods, landslides, and water quality degradation. This phenomenon is particularly pronounced in regions experiencing high rainfall intensity, coupled with inadequate land use and agricultural management practices. Understanding the primary factors behind the last decades escalation in land degradation and subsequent sediment export is crucial to prevent further ecosystem degradation and heightened instability in conflict-affected areas. To address this, we have developed an integrated approach involving core sampling, sediment fingerprinting techniques, high-resolution sediment sampling, and automated remote sensing routines to pinpoint hotspot areas and track conservation efforts. Using the Lake Kivu region as a case study, situated on the border between Rwanda and the Democratic Republic of the Congo, an area marked by prolonged violent conflict since the early 1990s, we evaluate the applicability of this combined approach.The preliminary results from the multiple techniques independently suggest an increasing trend in exported sediment over the last decade. This trend is particularly pronounced in areas characterized by high instability and economic challenges. In contrast, relatively more stable regions exhibit a stabilization in sedimentation rates. This stability is attributed primarily to the implementation of conservation practices and the presence of robust transport infrastructures, both playing crucial roles in landscape conservation. Results underscore the method's effectiveness in elucidating lasting effects on landscapes impacted by 'polycrisis', necessitating consolidated and comprehensive responses over mere technical solutions. The research objective is to target specific areas within conflict-affected regions, with a focus on mitigating environmental degradation and associated challenges.
Cations in Crisis: Limitation and Vulnerability of Secondary Forest Regrowth in dynamic Tropical Landscapes
Authors: Bauters Marijn , Van de Velde Viktor , W. Drake Travis , Boeckx Pascal , Ewango Corneille , Doetterl Sebastian , Makelele Isaac
Published: March 2024

Secondary forests will increasingly dominate tropical forest landscapes in the decades to come. Understanding how local biogeochemistry impacts regrowth trajectories is paramount, especially if this biogeochemistry is impacted by land-use change. In this study, we employ three lines of evidence from central African secondary forest succession sequences that suggest that cations might be a limiting and vulnerable resource to sustain secondary forest regrowth in the tropics.
First – along succussion, our analysis reveals that atmospheric phosphorus supply exceeds demand during forest succession, while plant base cation demands are met predominantly through depletion of soil stocks. As such, soil nutrient metrics indicate an increase in available phosphorus along the succession, contrasting with a decrease in available cations.  Coincidentally, fine root, foliar, and litter stoichiometry collectively demonstrate a decline in tissue calcium concentrations relative to nitrogen and phosphorus during succession. These findings collectively suggest that calcium becomes a progressively scarce resource in central African forests during secondary succession.
Second – also along succession, we show a substantial shift in ecosystem cation storage from soil to woody biomass over succession, while not for nitrogen or phosphorus,  rendering it a vulnerable nutrient in the context of land-use change scenarios involving woody biomass export. From independent data, we also show that with increasing repeated clearing, the total soil cation stocks are depleted, while we see no such consistent effect for nitrogen or phosphorus. Coincidentally, at a catchment scale, we see that cation losses increase as catchments get increasingly impacted by land-use change.
Third – based on a pot experiment, tree growth seems limited first and foremost by cations, and then by nitrogen. This again reiterates that cations might be an important and overlooked limiting element for sustaining plant growth in highly depleted tropical soils.
Collectively, this work calls for an expanded perspective on nutrient dynamics and highlights the vulnerability of cations in the face of changing land-use scenarios, with potentially important sustainability issues in the long-term – especially if the secondary regrowth potential is lowered.
Boosting CO2 sequestration potential of a degraded soil by hydrochar from sewage sludge
Authors: Amado-Fierro Álvaro , Forján Rubén , S. Santos Erika , R. Gallego José Luis , A. Centeno Teresa
Published: March 2024

A dramatic loss of healthy soils is occurring worldwide due to degradation and desertification by both natural and anthropogenic processes. Such actions accelerate the depletion of soil organic carbon (SOC), turning soil from a major CO2 sink to a source of CO2 emissions.On the other hand, global overpopulation is causing an unprecedented generation of sewage sludge. The high water content of sewage sludge makes it ideal for hydrothermal carbonization (HTC), a novel thermochemical conversion technology in which water acts as a reagent and catalyst to obtain a C-enriched solid known as hydrochar.In this study, the impact of a hydrochar (H) obtained from sewage sludge (HTC at 195 °C for 3 hours) and a biochar (B) produced by standard carbonization of holm oak (500 °C) on the capacity of a degraded soil for capturing carbon is evaluated. The soil under study comes from a landfill of industrial origin that over time was mixed with natural sandy soil, resulting in a technosoil with a low SOC content and incapable of supporting stable vegetation.The experiment was carried out in 60-l IBC containers, thus constituting a larger scale variation of the classic pot tests. Containers with only original soil (S) and those amended with 10 wt.% hydrochar (SH) and biochar (SB), after 15 days of stabilisation of the amendments, were vegetated with Lolium perenne and left for 12 months outdoors.At a depth of 0-10 cm, both treatments increased the concentration of labile fractions of SOC, extracted respectively with cold water and hot water. In contrast, in the 10-20 cm layer, this effect was also relevant in the container SH. This could be attributed to the migration of the hydrochar along the profile, facilitated by its finer particle size. Both materials, B and H, contributed positively to enhancing the amount of recalcitrant organic carbon (R) in the soil, although the impact was greater with the use of biochar. Average values of R~30 g·kg-1 have been detected for both 0-10 and 10-20 cm depths in the container with SB. In the case of SH, the migration of hydrochar led to R concentration of 13.08 g·kg-1 in the upper 10 cm and 27.40 g·kg-1 at 10-20 cm layer.Biochar and hydrochar efficiently managed to store organic carbon in soil, but the former caused a higher increase in reserves due to a greater contribution of recalcitrant carbon (Pearson correlation between R and SOC stock of 0.96, P < 0.01). The stock in SB reaches 48.13 and 32.10 tC·ha-1 at 0-10 and 10-20 cm, respectively, whereas the corresponding values in SH were 20.53 and 32.13 tC·ha-1.On the other hand, it was found that the 197 g of biomass generated in SC was reduced to 165 g when biochar was added, suggesting the capacity of B to fix certain nutrients and make them less accessible to vegetation in the short term. In contrast, hydrochar application increased the amount of vegetation to 478 g, thus favouring greater carbon sequestration.
Translating mineral systems criteria into a prospectivity model; Kolari region, Finland
Authors: Khammar Fereshteh
Published: March 2024

The Mineral Prospectivity Mapping (MPM) methodology can be used to delineate favorable mineral exploration areas and minimize time and costs. The mineral deposits in Finland are an ideal testing ground for these methods due to limited outcrops, thick overburden because of soil cover and dense vegetation and snow cover during long winters. Here, we apply MPM to predict favorable areas for Iron Oxide-Copper-Gold (IOCG) deposits in the Kolari region, northwestern Finland. We use a GIS-based knowledge-driven approach (fuzzy logic overlay), which is integrating evidential layers derived from geological (scale-free geology map), geochemical (till and bedrock samples), and geophysical data (magnetic, radiometric, electromagnetic measurements and gravity worms). The regional-scale analysis aimed to evaluate various mineral system components specified for IOCG deposits, including the anomalies of elements in till and rock geochemistry (i.e., Au, Cu, Co, Fe, and Th), pathways, energy sources/drivers, traps, and the relevant geological factors influencing the ore-forming processes. Utilizing the Centered Log-Ratio transformation (CLR) proves beneficial in enhancing the identification of weak anomaly areas and improving the prospectivity assessments by directing attention to relevant geological features. The produced prospectivity map shows a positive association between known IOCG deposits and high-favorability areas, and it also indicates new promising targets. Receiver Operating Characteristic (ROC) analysis and average Area Under the Curve (AUC) values consistently yielded scores > 0.7 which could be considered favorable outcomes (promising targets).
Analysis of the resolution of precipitation data required to obtain robust results from a hydrodynamic sewer network model
Authors: Rabiei Ehsan , Hoppe Holger , Lebrenz Henning
Published: March 2024

The need for precipitation data for calibrating hydrodynamic sewer network models is often compromised by using the nearest available rain gauges to study area. Due to the scarcity and irregular locations of the rain gauges, this way of satisfying the need for precipitation data can lead to incorrect conclusions with respect to the temporal and spatial patterns of precipitation, depending on the location of the rain gauges in the study area. Recent developments in the field of precipitation measurement by means of weather radar data open up new possibilities for the use of such data sources in hydrodynamic sewer network models. Even though weather radar provides precipitation information with a high temporal and spatial resolution, the raw radar data contains several sources of error and is inaccurate. The radar data are therefore often corrected and merged with ground measurements. The main objective of this study is to investigate the resolution of precipitation data required to obtain robust results in a hydrodynamic channel network model. The study area is a small catchment close to Munich in Bavaria, Germany. Data from the Isen weather radar station of the German Weather Service (DWD), which is located around 33 km from the study area, was used. Following the objectives of this study, various weather radar data products were processed in order to be used as input for a hydrodynamic sewer network model. The data with a temporal resolution of 5 minutes to 1h and a spatial resolution of 250 m x 250 m up to 1.000 m x 1.000 m form the basis for creation of datasets to be investigated. It has been observed that the use of high-resolution precipitation data leads to better model results, especially when the data is merged with rain gauges. However, it should be noted that the quality of the model results does not decrease linearly when the resolution of the precipitation data is reduced.
Combined Effect of Brittle Off-Fault Damage and Fault Roughness on Earthquake Rupture Dynamics
Authors: Thomas Marion Y. , S. Bhat Harsha
Published: March 2024

Natural fault zone are complex objects. They not only consist of a fine-grained narrow fault core where the extensive shearing is observed, but it is also surrounded by pervasively fractured rocks, within an intricate 3-D geometry. If fault slip behavior is intrinsically linked to the properties of the fault core, the complex structure of fault zone systems impacts the rheological properties of the bulk, which influence the modes of deformation, and slip, as underlined by recent observations. Fault zone structure is therefore of key importance to understand the mechanics of faulting. Within the framework of a micromechanics based constitutive model that accounts for off-fault damage at high-strain rates, this numerical study aims to assess the interplay between earthquake ruptures along non-planar fault and the dynamically evolving off‐fault medium. We consider 2D inplane models, with a 1D self-similar fault having a root mean square (rms) height fluctuations of order 10-3 to 10-2 times the profile length. We explore the dynamic effect of fault-roughness on off-fault damage structure and on earthquake rupture dynamics. We observe a high‐frequency content in the radiated ground motion, consistent with strong motion records. It results from the combined effect of roughness-related accelerations and decelerations of fault rupture and slip rate oscillations due to the dynamic evolution of elastic moduli. These scenarios underline the importance of incorporating the complex structure of fault zone systems in dynamic models of earthquakes, with a particular emphasis on seismic hazard assessment.