bluuebunny/crossref_metadata_2025 huggingface dataset:
Small-scale spatial relationships between peat properties and surface microtopography in minerotrophic peatlands depend on management regimes
Authors: Ahmad Sate , Bates Adam , Wang Miaorun , Martini Francesco , Regan Shane , McElwain Jennifer , Gill Laurence
Published: March 2024

Fens, in their natural states, are characterized by rich biodiversity and high carbon and water storage, playing a major role in providing several important ecosystem services. However, most fens in Europe were drained in the past for agriculture, leading to degradation and a reduction of their multifunctionality. While restoration, primarily through rewetting, is gaining prominence in Europe, there are substantial knowledge gaps in understanding spatial landscape and ecosystem processes in these environments, rendering successful restoration or rehabilitation of functions challenging. Determining peat properties and their relation to soil surface processes at small scales is key to revealing different pathways that ecosystem recovery may take, not only in terms of carbon storage but also hydrophysical functioning. In the absence of long-term monitoring of fen peatlands, both pre- and post-rewetting, drained and rewetted paired comparison studies are the next best approach to study the effects of drainage and rewetting and how degraded peatlands differ from their near-natural counterparts. Here, we compare the spatial structures of peat properties, such as soil moisture content, soil organic matter, and carbonate content, in a drained and a rewetted fen peatland in Ireland and investigate how surface microtopography influences such properties. This is done by constructing variograms and investigating the differences in range, partial sill, and nugget-to-sill ratio. Overall, soil properties in the near-natural fen show much lower spatial autocorrelation based on nugget-to-sill ratios, and these properties reach autocorrelation range at much shorter distances compared to those of the drained site. This indicates that the drained site is more homogeneous in terms of soil properties compared to the near-natural fen. The bivariate autocorrelation between the different soil properties and surface microtopography is much stronger in the drained site compared to the rewetted site, indicating that surface microtopography plays a larger role in controlling ecosystem processes in drained peatlands than in the near-natural fens. Our results highlight the importance of spatial peat sampling at short intervals for small-scale processes and for the identification of carbon storage hotspots and formulation of appropriate monitoring scale and plan.
Multi-year dynamics of soil structural stability under contrasting farming practices in a belgian organic field experiment
Authors: Vanwindekens Frédéric , Hardy Brieuc , Abras Morgan , Sail Simon , Huyghebaert Bruno
Published: March 2024

At the heart of agro-ecosystems lie soils, essential components profoundly affected by intensive farming practices and global changes across various regions in Europe. This impact manifests as a loss of biodiversity, a decline in organic matter content, and heightened susceptibility to erosion. Recognizing these challenges, certain farmers are embracing innovative approaches to enhance soil quality, such as conservation farming and organic farming. These two systems differ significantly in their weed management practices, with conservation farming relying on synthetic herbicides and reduced tillage, while organic farming predominantly employs tillage.To assess soil structural stability, we developed a new measurement protocol, the QuantiSlakeTest. This low-tech method operates on the principle of continuous quantitative measurement, evaluating the disintegration of a soil sample submerged in water. The resulting curves are normalized, and synthetic indicators, including relative weights at stabilization, time to reach maximum relative weight post-immersion, diverse slopes, and area under the curve, facilitate the comparison of various treatments.Building on previous research demonstrating the relevance of this approach and the influence of tillage on soil structural stability (Vanwindekens & Hardy, 2023), our study employed the QuantiSlakeTest to highlight the annual evolution of soil structure stability over three years following the implementation of an organic cropping system trial in Gembloux (Wallonia, Belgium). Initiated in 2019, the trial involved converting a conventional 6 ha field to a seven-year rotation of organic farming. The three compared cropping systems differed in weed control, fertilization, and tillage practices. Soil samples were collected in early spring of 2020, 2021, and 2022 from various crops in the trial, including winter cereals, spring cereals, legumes, and maize, with cover crops or even uncovered after a winter ploughing.Our main findings reveal a gradual differentiation of soil structural stability indicators during the first three years of cultivation. Cropping systems based on reduced tillage practices demonstrated a positive impact on soil structural stability, particularly in the third studied year (2022), while reference systems exhibited lower rates. These results confirm previous studies. We also detect a slight positive impact of legumes, cover crops, and/or crop associations, even in the two cropping systems with ploughing (2022). Further analyses, to be conducted over the seven years rotation will shed additional light on the dynamics of soil structural stability.Frédéric M. Vanwindekens and Brieuc F. Hardy (2023). The QuantiSlakeTest, measuring soil structural stability by dynamic weighing of undisturbed samples immersed in water, SOIL, 9, 573–591, https://doi.org/10.5194/soil-9-573-2023
Sea ice, snow caps, and freshwater lenses: The hurdles local Arctic aerosols must overcome to become airborne
Authors: Creamean Jessie ,   MOSAiC and ARTofMELT field teams
Published: March 2024

Aerosol particles and clouds play a critical role in regulating radiation reaching the Arctic, which is warming faster than anywhere else globally. However, the magnitude of their effects is not adequately quantified, especially in the Arctic Ocean over sea ice. Specifically, particles generated from open leads, melt ponds, and the snow-covered sea ice surfaces remain poorly understood, yet could have significant impacts on cloud condensation nuclei (CCN) and ice nucleating particle (INP) concentrations, and thus, central Arctic cloud formation. While marine biological processes have been demonstrated to be potentially key primary aerosol sources in the Arctic summer, exact sources and emission processes of these particles remain highly uncertain. For this presentation, we provide an overview of aerosol observations from two recent Arctic field campaigns: the 2019–2020 Multidisciplinary drifting Observatory for Study of Arctic Climate (MOSAiC) and the 2023 Atmospheric rivers and the onset of Arctic melt (ARTofMELT) expeditions. We highlight preliminary findings focused on aerosols that have the potential to impact cloud phase and lifetime over the Arctic Ocean, specifically those from local sources in the early spring and summer melt periods. The evolution of open water within the pack ice in late spring and the Arctic melt season coincides with an increase in aerosol particle concentration, which may be attributed to biological activity within seawater and sea ice. However, the emission of aerosol particles is contingent on features like open leads and melt ponds, and whether they are covered by snow, freshwater melt layers, or ice lids. This integrative study involves the use of detailed aerosol, meteorological, oceanographic, and sea ice observations from MOSAiC and ARTofMELT. Overall, this work will enable us to assess local aerosol processes associated with cloud formation to better understand the Arctic system through a holistic approach.
How stocks judge COPs: market impacts of climate conferences
Authors: Lamboll Robin , Al Khourdajie Alaa
Published: March 2024

This study investigates the impact of Conference of the Parties (COP) meetings on the stock prices of oil companies and the broader implications for renewable energy sectors to examine the relationship between international climate negotiations and market responses in the energy sector. The analysis focuses on stock price movements and volatility within the oil and renewable energy industries. We look at the data of the 10 largest stocks in each category and investigate their behaviour during COP. The findings indicate that, with the exception of notable negative stock price movements during COPs 20 and 21 (before and during the signing of the Paris Agreement), COP meetings generally do not significantly influence the value of oil companies. There is also no impact on oil prices during COP itself, though some sign of disturbance in the period immediately afterwards. The study also addresses the renewable energy sector, finding no strong effects from most COP meetings but a notable decrease in stocks during COP6's failure. We conclude that the majority of COPs have not produced market signals indicating a green transition, although these signals are potentially detectable.
Long-term landslide ecological monitoring: the case of Pomezzana, Tuscany.
Authors: Dani Andrea , Giachi Emanuele , Preti Federico , Cabrucci Marco , Pollastrini Martina , Bellabarba Agnese , Viti Carlo , Decorosi Francesca , Giambastiani Yamuna
Published: March 2024

Land degradation and soil erosion due to increasingly frequent extreme hydro-meteorological events, has negative consequences on ecological processes, making the environment, particularly rural and mountain areas, more susceptible to biodiversity loss. Nowadays, the use of plants as a building material transfers the plant multifunctionality within engineering structures and meets the demand rising from society for more environmentally friendly approaches to structure design. EU strategies and regulations require the employment of Nature-Based Solutions, such as Soil and Water Bioengineering techniques (SWBE).   Soil and Water Bioengineering techniques are applied worldwide, achieving great results for slope and streambank stabilization, water regulation, landslides restoration and for mitigation of environmental impacts. SWBE techniques manage natural hazard control using plants as living material in combination with inert natural material, achieving two main goals: on the one hand the technical function of stabilizing the soil on the other hand the mitigation of environmental damage, initiating natural ecological processes. The research aims to evaluate the technical and ecological recovery effectiveness of a SWBE intervention for the restoration of a shallow landslide, occurred during Versilia flood in 1996. The project aims to monitor the evolution of vegetation and evaluate the composition of soil microorganisms by comparing the area restored by the intervention and surrounding areas. Field samplings and analysis will be conducted on two landslide bodies that occurred with the same extreme rainfall event: first site a landslide restored with SWBE techniques and the second site a naturally evolving landslide. A multi-approach methodology will be developed to evaluate differences and correlation between the ecological processes (vegetation and soil microorganism) and the technical efficiency of the landslide restoration intervention.
Automated Mineralogy – A Valuable and Data-Rich Product to Advance the Green Energy Transition  
Authors: Pfaff Katharina
Published: March 2024

Automated mineralogical analysis (quantitative scanning electron microscopy) is a powerful tool that has been used extensively to understand the occurrence and deportment of precious and base metals and critical minerals and is used to optimize the design of extractive metallurgy methodologies. However, this data-rich product can also be used in a predictive context and as the basis for data integration across the range of scales. Automated mineralogical data include quantitative mineral abundance and textural data that can form the basis for machine learning algorithms to improve statistical subsampling strategies, data integration, mineralogical upscaling, and to increase the value of x-ray fluorescence- and hyperspectral data.   The Mineral and Materials Characterization Facility in the Department of Geology and Geological Engineering at the Colorado School of Mines in Golden, USA, houses two scanning electron microscopy-based automated mineralogy systems. These systems are used to conduct research over a broad range of disciplines including all stages of the mine life cycle, energy and petroleum resources investigations, provenance and climate studies, and environmental and biological studies.   During this presentation, we will explore examples of how automated mineralogy can play a crucial role across the mine life cycle that spans from mineral exploration, mine planning and mining, extractive metallurgy, proactive waste rock and tailings management, to reclamation. The example use-inspired research projects, conducted through the Center to Advance the Science of Exploration to Reclamation in Mining (CASERM) using the Advanced Mineral Analysis and Characterization System (AMICS) from Bruker based on a field-emission scanning electron microscope from Hitachi, focus on the integration of diverse geoscience data types to accelerate and improve decision making across the mine life cycle.   Quantitative scanning electron microscopy provides important mineralogical and textural data that can inform statistical, thermodynamic, and kinetic models. These data improve not only our understanding of the subsurface in the context of hard-rock mining, but can inform other disciplines such as geothermal energy exploration and extraction and understanding the carbonation potential, helping move the world towards a greener future. 
QUANTOM – QUANTification of dissolved Organic Matter and the metabolic balance in river networks: mechanisms and model simulations of CO2 emissions
Authors: Demars Benoit , McGovern Maeve , Jackson-Blake Leah , Sample James , Norling Magnus , Høgda Kjell , Karlsen Stein , Dörsch Peter , Stutter Marc , Thornton Barry , Junker Jim , D'Andrilli Juliana
Published: March 2024

QUANTOM aims to quantify how changes in quality and quantity of dissolved organic matter (DOM) supply alter the metabolic balance of rivers, i.e. the contribution of in-stream DOM degradation to CO2 emissions. QUANTOM will determine the coupling between land vegetation growth from satellite observation and DOM delivery and transformation in streams using in-situ sensor technology and whole stream metabolism. QUANTOM will characterise the molecular transformations (reactive pathways) of DOM, from riparian soils to the Barents sea, through the river continuum at control points (hot spots and hot moments) using carbon stable isotope ratios and FT-ICR-MS. QUANTOM will formalise mathematically our novel understanding into a parsimonious river basin model for DOM with in-stream processes. QUANTOM’s vision is to have a model applicable across the natural northern rivers around the globe and transform the way we see and study rivers.We have completed three years of fieldwork in the river Tana (Northern Norway), draining 16,000 km2 of north boreal and sub-arctic landscapes and discharging in the Barents sea (70°N). We will present the outline of the project, our conceptual approach and preliminary results such as satellite and in-situ sensor data, carbon fluxes and metabolic balance of the river network.   
Subduction polarity reversal facilitated by plate coupling during arc-continent collision
Authors: Tao Zaili , Yin Jiyuan
Published: March 2024

Subduction polarity reversal usually involves the break-off or tearing of downgoing plates (DPs) along the continent-ocean transition zone, in order to provide space for the overriding plate (OPs) to descend. Here we propose that subduction polarity reversal can also be caused by DP-OP coupling and that it can account for the early Paleozoic geological relationships in the West Kunlun Orogenic Belt (WKOB). Our synthesis of elemental and isotopic data reveals transient (~5 Myr) changes in the sources of the early Paleozoic arc magmatism in the southern Kunlun terrane. The early stage (530–487 Ma) magmatic rocks display relatively high εNd(t) (+0.3 to +8.7), εHf(t) (−3.6 to +16.0) values and intra-oceanic arc-like features. In contrast, the late-stage (485–430 Ma) magmatic rocks have predominantly negative εNd(t) (−4.5 to +0.3), εHf(t) (−8.8 to +0.9) values and higher incompatible trace elements (e.g., Th), similar to the sub-continental lithospheric mantle (SCLM) beneath the Tarim Craton. This abrupt temporal-spatial variation of arc magmatism, together with the detrital zircon evidence, indicate that subduction polarity reversal of the Proto-Tethys Ocean occurred in a period of ~10 Ma, consistent with migration of the magmatic arc. This rapid polarity reversal corresponds with the absence of ultra-high-pressure metamorphic [(U)HP] and post-collisional magmatic rocks, features normally characteristic of the slab break-off or tearing. Numerical modeling show that this polarity reversal was caused by plate coupling during arc-continent collision without slab break-off and tearing. This prevented rebound of the positively buoyant relic rocks and asthenosphere upwelling. This model successfully explains the early Paleozoic orogenesis in the WKOB and may be applied elsewhere where post-collisional magmatic and (U)HP rocks are absent.
Characterization of Extreme Rainfall Events Severity in Calabria: Exploring Spatial-Temporal Variability through Severity Diagrams
Authors: Biondi Daniela , Bloise Sara
Published: March 2024

This study aims to identify key characteristics of rainfall events, such as critical duration, extent, and severity (i.e., return period), to unveil potential dependencies with the resulting impact scenarios. Severity diagrams, introduced by Ramos et al. (2005) serve here as a straightforward tool, providing a synthetic visualization of storm severity while accounting for the complexity associated with rainfall spatial variability and duration. The method emphasizes the coexistence of extreme and ordinary (non-extreme) rainfall intensities. In contrast, the conventional approach of assigning a single return period to an event obscures a significant portion of storm complexity by overlooking spatial variability. Maximum mean areal precipitations observed over different areas during the storm event are evaluated. Subsequently, maximum equivalent point rainfalls are derived using ARF (Areal Reduction Factor) estimation, and their return period values deduced from the IDF (Intensity Duration Frequency) curves. The return periods are eventually mapped as a function of area and duration of rainfall accumulation. Several damaging storm events observed in the Calabria region (south Italy) over the last 20 years have been selected as illustrative examples for the analysis.
Interglacial beach ridge plains across the northern Gulf of Mexico
Authors: Georgiou Nikos , Dean Silas , Simms Alexander R. , Chauveau Denovan , Cerrone Ciro , Rovere Alessio
Published: March 2024

During past Interglacial periods, global ocean volume increased as a result of the higher temperatures and the melting of ice sheets, consequently leading to a rise in global sea levels. However, on timescales ranging from years to a few decades, regional sea level variability deviates from the global pattern, due to a combination of vertical land movements (earth’s crust viscoelastic response to glacial and ice sheet melting, tectonics), thermohaline circulation, wind forcing and land water storage. Therefore, decoding the regional sea-level variability during Interglacial periods is crucial for advancing climate models’ precision, especially for vulnerable coastlines.Beach ridge plains are valuable fossil geological archives, offering significant potential for the analysis of sea-level fluctuations, climatic shifts and catastrophic events. The extraction of these information can be achieved through the measured elevation of the dune-beach contact and the beach berm, the analysis of the fossil beach ridge orientation, the geometry of the internal stratigraphy and by dating of the beach deposits using optically stimulated luminescence (OSL) signals from quartz.In this study, we present results from our fieldwork campaign in the northern Gulf of Mexico, where we utilized a GNSS RTK station to obtain centimeter-level precision in measuring the elevation of the beach ridge sets, originally detected through freely available LIDAR datasets. Concurrently, a Ground Penetrating Radar (GPR) was employed to determine the stratigraphy of the beach ridge plains. Both surveyed areas, Apalachicola and Pensacola, contain fossil beach ridge sets varying in elevation from +2.5m up to a maximum of +7.5-8m above mean sea level, detected in more inland locations. Recent studies suggest that during the Last Interglacial period sea level in the area reached up to ~5m. The exact timing of the formation of the more elevated inland beach ridges remains uncertain, as does the question of whether their present elevation is attributable to post-Last Interglacial vertical land movements. Through in-depth analysis of the data collected during the WARMCOASTS ERC project, we aim to unravel the formation processes of these beach ridges and trace their development and evolution over time.
Utilizing deep neural networks for landslide detection and segmentation in remote sensing imagery
Authors: Lampert Jasmin , Pham Lam , Le Cam , Schlögl Matthias , Schindler Alexander
Published: March 2024

Understanding the occurrences of historic landslide events is crucial for supporting strategies aimed at reducing disaster risks. Drawing from insights obtained in the 2022 Landslide4Sense competition, we present a methodological framework reliant on a deep neural network design for the detection and segmentation of landslides using input from various remote sensing sources. Our approach involves using a U-Net architecture, initially trained with cross entropy loss, as a baseline. We then enhance this architecture by employing diverse deep learning techniques. Specifically, we engage in feature engineering by creating new band data derived from the original bands, thereby improving the quality of the remote sensing image input. Concerning the network architecture, we substitute the conventional convolutional layers in the U-Net baseline with a residual-convolutional layer. Additionally, we introduce an attention layer that capitalizes on a multi-head attention scheme. Furthermore, we generate multiple output masks at three distinct resolutions, forming an ensemble of three outputs during the inference process to augment performance. Lastly, we propose a composite loss function that integrates focal loss and IoU loss to train the network effectively. Our experiments on the Landslide4Sense challenge's development set yield an F1-score of 84.07 and an mIoU score of 76.07. Our optimized model surpasses both the challenge baseline and the proposed U-Net baseline, improving the F1-score by 6.8/7.4 and the mIoU score by 10.5/8.8, respectively.
Fluid-mediated reactivation of brittle faults in the Bristol Channel Basin, UK
Authors: Anderson Mark , Connolly Joe , Mottram Catherine , Price Gregory , Sanderson David
Published: March 2024

Faults act as sites for preferential failure in the continental crust when it is subjected to sequential tectonic events. To do so, they will typically have favourable orientation, geometry and/or be weaker than the adjacent crust and are therefore prone to slip. However, fluid flow that is focussed along faults has a role in modifying their mechanical strength, especially where different fluids, and resulting mineralisation, are partitioned along particular structures. The East-Quantoxhead Fault (EQHF) in the Bristol Channel Basin (BCB), SW England has been identified as a reactivated normal fault with multiple slip events, the cause and precise timing of which are unknown. Using U-Pb geochronology of calcite veins located in the fault core we show that the timing of mineralisation (as a proxy for fluid flow) along the EQHF spans from 151-35 Ma. Microstructural analysis of different vein generations within the fault core shows that the longevity of this structure is a result of progressive weakening of the fault core. Initially this is represented by crystal plastic deformation of early-stage calcite mineralisation in the fault core, compatible with protracted phases of normal-sense slip. This is most likely mediated by the flow of syn-kinematic fluids that are hotter than the ambient temperature of the wall-rocks. However, later weakening of the fault core results from the precipitation of relatively weak fibrous celestine (SrSO4) along the margins of older calcite veins. Celestine shows evidence of reverse-sense S-C fabrics and was therefore a site of strain localisation and fault reactivation during regional contraction. This later fluid is sourced from deeper formations within the BCB which are only accessed by larger faults like the EQHF. Smaller normal faults in the BCB containing no celestine do not show a protracted fluid history, however crystal plastic textures (GBM, SGR) can also be seen within these faults. Understanding the role different fluids play in altering fault core composition, and strength via the analysis of vein textures plays a key role in understanding the partitioning and significance of fluid flow along fractures. 
Enhanced aerosol-induced near-term Arctic warming due to remote regional aerosol perturbations in RAMIP
Authors: Westervelt Daniel , Zhang Yanda , Amooli Joe Adabouk , Tsigaridis Kostas , Nazarenko Larissa , Samset Bjørn , Wilcox Laura , Allen Robert
Published: March 2024

The climatic implications of regional aerosol and precursor emissions reductions implemented to protect human health are poorly understood. However, quantitative estimates of climate responses to emission perturbations are needed by the climate assessment and impacts community. The Regional Aerosol Model Intercomparison Project (RAMIP) project builds on recent CMIP5 and CMIP6-era studies to help address this knowledge gap. Briefly, RAMIP will use contrasting SSP aerosol emissions (SO2, BC, OC) scenarios (SSP3-7.0 and SSP1-2.6) to isolate the impact of realistic, near term aerosol changes on climate and air quality over rapidly developing regions of South Asia, East Asia, and Africa, and over North America and Europe. At least 9 CMIP6-generation global climate models are contributing to this new MIP, which uniquely focuses on specific regional aerosol emissions changes rather than simultaneous global changes. This presentation will specifically present the first results from several participating models in RAMIP, namely the NASA Goddard Institute for Space Studies (GISS) ModelE, UKESM, CESM2, and NorESM. All Tier 1 simulations of RAMIP are included, with 10 ensembles for each simulation. Initial analysis at the time of writing confirms the anticipated changes in aerosol optical depth, downwelling shortwave radiation, and aerosol mass concentration over each of the regions. The warming response to a decrease in SO2, BC, and OC is strongest in the US and Europe perturbation simulations, both globally and regionally, with Arctic warming up to 0.3 K due to a removal of US and European anthropogenic aerosol emissions alone; however, even emissions from regions more remote to the Arctic, such as South Asian aerosols, can significantly warm the Arctic up to 0.2 K. In most regions, temperatures are most sensitive to emissions perturbations within that region. Arctic warming is the most robust model response across the regional aerosol emissions perturbations. 
Relative Contribution of External Forcing and Internal Climate Variability to Lagged Dry-Wet Swing Projections in North America
Authors: Najafi Mohammad Reza , Na Wooyoung , Grgas-Svirac Andrew
Published: March 2024

Hydroclimatic whiplash, a lagged compound hazard combined with preceding drought (flood) and following flood (drought), may induce significant environmental, hydrological, and socio-economic impacts worldwide. North America is one of the hot spots becoming susceptible to the transitions or shifts between two extremes. These compound events are also expected to become more frequent and intense in the future under climate change. To better understand the climate influence, overall decadal changes in climate variables and related hydroclimatic swing events need to be analyzed considering two components: anthropogenic external forcing and natural internal variability. External forcing is induced by anthropogenic activities imposing greenhouse gas emissions on the climate system, resulting in the signal of global warming. Internal climate variability (ICV), also termed climate noise, is an irreducible uncertainty induced by the chaotic nature thus unpredictable evolution of the climate system. In this study, we use four single-model initial-condition large ensembles (SMILEs) under historical and future forcing scenarios (RCP8.5), CanLEAD-EWEMBI, CanLEAD-S14FD, CanRCM4-LE, and GFDL-SPEAR, to quantify the relative role of external forcing and ICV on variations in compound dry-wet swing events across North America. The SMILE enables the robust quantification of the externally forced response and internal variability via computation of ensemble statistics, provided the ensemble size is large enough. On the virtue of this advantage, the standardized precipitation evaporation index is estimated to identify dry and wet spells and their transitions based on ensemble pooling and threshold-based event extraction methods. Frequency, intensity, transition time, transition intensity, and relative role of preceding and following spells, etc. are quantified for each warming period (1.5°C-4 °C global warming levels) and compared with those of the baseline period to investigate their projected changes and trends. The relative contribution of ACC and ICV to compound dry-wet spells is quantified by the ratio of changes and trends in the ensemble mean and the spread (standard deviation) among the ensemble members of each SMILE, respectively. The results of this study suggest that hydroclimatic swing events across North America are expected to become more frequent and intensified in a warmer climate, which is induced by significant emergence of external forcing. In addition, the transition time and transition intensity are projected to be more dominated by anthropogenic forcing over ICV than other characteristics indicating that more abrupt and severe shifts can occur in the future. The findings of this study support the necessity of developing appropriate measures for mitigating the anthropogenic forcing impact because it increases the risk of lagged compound floods and droughts that can lead to severe disasters in North America.
The impacts of ocean physics on the efficiency of ocean alkalinity enhancement in a one-dimensional model
Authors: Musgrave Ruth , Yee Ruby , Rackley Steve , Wagner Greg
Published: March 2024

We use a one-dimensional diffusion model to examine the relative effects of air-sea gas exchange and interior mixing on the efficiency of ocean alkalinity enhancements in drawing down atmospheric CO2 under a range of oceanic conditions. First, a series of highly idealized simulations are run to explore the impacts of deployment depth, wind speed, mixed layer depth, interior diffusivities and seasonality on the efficiency of CO2 uptake following an alkalinity addition. For additions made within the mixed layer subject to typical wind speeds and diffusivity profiles, we find efficiencies one year after deployment of around 50%, with wind speeds playing a dominant role in determining efficiency compared to mixed layer depth or interior diffusivities. Next, we use wind speeds, surface buoyancy and momentum fluxes from reanalysis to produce realistic, time varying diffusivities that we use to drive the model, producing estimates of efficiencies at different global locations over one annual cycle. Our simulations lend insight into the underlying processes that determine OAE efficiency and aid in the interpretation of similar calculations that have been performed using more complex models.
Incorporating Ethics into Climate Intervention Research, Experimentation, and Potential Deployment
Authors: Shimamoto Mark , Lachance Janice , Williams Billy
Published: March 2024

Climate change requires urgent action. Aggressive actions toward carbon emissions reduction must remain the primary strategy for reversing and addressing climate change. However, increasingly the world is considering technology-based climate intervention approaches—often called climate engineering. There are major practical and ethical questions about the significant risks and potential trade-offs some of these approaches would bring and how they would be measured against the risks of our warming world. Recognizing the need for guiding principles in this fast-moving, dynamic space and building on AGU’s longstanding history of advancing and advocating for strong scientific ethics, AGU is facilitating the development of a draft Ethical Framework for Climate Intervention Research, Experimentation, and Deployment. The ethical framework will be released in 2024 and will serve as a resource to help governments, researchers, NGOs, and the private sector make responsible decisions when engaging in climate intervention research or policy. In 2023, the draft framework completed a rigorous three-month public comment period and consultation process to include more holistic input from other scientists and ethicists, as well as community voices, youth advocates, and many more. This presentation will highlight the ethical principles and how the science community can incorporate and advocate for ethics in climate intervention research.
Quantifying the influence of matrix diffusion on transit time distributions (TTDs) in mountain catchments
Authors: Rajaram Harihar
Published: March 2024

Solute transit or travel time distributions (TTDs) are relevant to both hydrochemical response and inference of hydrologic mechanisms in catchments.  A significant fraction of streamflow in mountain catchments is derived from groundwater flow through fractured bedrock.  It is well established that matrix diffusion significantly influences the travel time of tracers in fractured rock.  However, few models of catchment TTDs explicitly incorporate the influence of matrix diffusion.  I present theoretical analyses of the combined influence of matrix diffusion and variable advective travel times along streamlines, on the total TTD in a catchment hillslope flow system in both the frequency and time domains.  The frequency domain analyses reveal that matrix diffusion inherently leads to 1/frequency or “fractal scaling” behavior, which has been widely documented.  Application to the Lower Hafren experimental watershed at Plynlimon, Wales, shows that theoretical stream concentration power spectra match observations very well.  Time-domain analyses reveal that matrix diffusion leads to TTDs that decline steeply at early times and also exhibit long tails, consistent with gamma distributions with shape parameter α = 0.5 (or more generally < 1).  I present illustrative applications of the time-domain analysis to interpret environmental tracer observations (tritium-helium, 3H-3He; and sulfur hexafluoride, SF6) from two mountain catchments in Colorado, USA.  Both catchments are underlain by fractured bedrock and environmental tracer transport is likely influenced strongly by matrix diffusion. The time-domain model employs a fitted advective travel time distribution and involves two additional dimensionless parameters: the first is a measure of the strength of matrix diffusion and the second represents the influence of the accessible matrix diffusion thickness.  These parameters were assigned based on field information, with minor adjustments. Results illustrate the significant influence of matrix diffusion on TTDs in mountain catchments with fractured bedrock, and parsimonious approaches to representing this influence.
Comparative evaluation of two physically-based mass conservative variable parameter Muskingum models
Authors: Perumal Muthiah , Rao C Madhusudana
Published: March 2024

The comparative performances of two variable parameter Muskingum flood routing models are evaluated in this study from the perspective of overall reproduction of the routed flood hydrographs characterized by different magnitudes of attenuation of the routed benchmark hydrographs. These two models are the Variable Parameter Muskingum-Cunge-Todini (MCT) model advocated by Todini in 2007, and the Variable Parameter McCarthy-Muskingum (VPMM) model advocated by Perumal and Price in 2013. To investigate this objective, routing studies were undertaken by routing a given hypothetical inflow hydrograph in 25 hypothetical trapezoidal channel reaches of the same geometrical size, but each characterized by different unique combinations of channel bed slopes and Manning’s roughness coefficients. The study results demonstrate that the VPMM model is capable of better reproduction of different levels of attenuation of the routed benchmark hydrographs in small bed slope channels in comparison with that of the MCT model. However, for steep and very steep bed slope channels, where the attenuation is small or insignificant, both the VPMM and MCT models perform equally well due to the reason that the latter model is a specific case of the former model. The study concludes that the application of the VPMM model is more suitable for field routing studies than the MCT model, when the magnitude of the water surface gradient of the inflow hydrograph is characterized by an absolute magnitude of (1/S0) ∂y/∂x where, S0 and ∂y/∂x are, respectively, the bed slope of the channel and the relative water surface gradient of the inflow hydrograph. The added advantage of employing the VPMM model is that it has the capability of estimating the stage hydrograph at the end of the routing reach or sub-reaches corresponding to the routed discharge hydrograph in a manner consistent with the numerical solution approach of the full Saint- Venant equations.
An Integrated Approach for Estimation and Uncertainty Analysis of Soil Pore Electrical Conductivity
Authors: Sanchez-Espigares Jose A , Aljoumani Basem , Kleinschmit Birgit
Published: March 2024

This study proposes an integrated methodology to advance the estimation and uncertainty analysis of soil pore electrical conductivity. Drawing on previous work from Aljoumani et al. (2015), where modifications were made to the Hilhorst model, and subsequent enhancements in Aljoumani et al. (2018), this research unfolds in a systematic manner.Commencing with a comprehensive examination of critical data from the Aljoumani el al.(2015) study, including bulk electrical conductivity, soil permittivity, and pore water permittivity, we transition into the construction of an improved Hilhorst model. This advanced model convert the deterministic Hilhorst model to stochastic model incorporates linear dynamic modeling and the Kalman filter, enabling precise estimation of soil salinity (pore electrical conductivity) and determination of corresponding offsets.To address uncertainty comprehensively, we employ a multifaceted strategy. Beginning with the modeling of relationships using the Long Short-Term Memory (LSTM) algorithm, an artificial recurrent neural network, we intricately examine the interplay between the original time series of soil permittivity, pore water permittivity, and bulk electrical conductivity.Subsequently, we utilize bootstrapping to generate 1000 series for soil permittivity and pore water permittivity. The LSTM model then produces 1000 series of bulk electrical conductivity, using the generated soil and pore water permittivity series as input.Applying the modified Hilhorst model to the 1000 series obtained from bootstrapping and the LSTM model, we obtain 1000 models, each providing 1000 offsets and predicted pore water electrical conductivity series. Returning to the original data, the modified model is applied to construct predicted series of pore electrical conductivity. Upper and lower bounds are established using the calculated 5th and 95th percentiles of the 1000 offset values from the generated data.In summary, this integrated methodology not only ensures accurate estimations of soil pore electrical conductivity but also provides a robust framework for quantifying uncertainty comprehensively.
Study on the durability of the biocementation treatment of a Portuguese motorway slope 
Authors: Cardoso Rafaela , Oliveira Mário , Cruz Miguel , Gonzalez Isabel , Rodrigues Ana Teresa , Sapin Leslie , Esnault-Filet Annette
Published: March 2024

Biocementationconsists in using biological agents such as bacteria or enzymes to promote the precipitation of calcium carbonate. This environmentally sustainable technique was applied to treat an excavation slope in sandy soil on a Portuguese motorway, aiming to prevent erosion and the formation of ravines caused by water flow. The slope has been monitored for over one year as part of an ongoing project funded by FCT (ref. PTDC/ECI-EGC/1086/2021). The results of the first campaigns are presented, consisting in the time evolution of the amounts of calcium carbonate. The results confirm the durability of the treatment, also confirmed by laboratorial tests performed on samples of the same soil treated with the same protocol and after being submitted to 10 wetting and drying cycles.
Low-frequency sferics associated with consecutive Terrestrial Gamma-ray Flashes 
Authors: Zhang Hongbo , Qie Xiushu , Lu Gaopeng
Published: March 2024

Terrestrial Gamma-ray Flashes (TGFs) are brief and intense emissions of hard X-rays and gamma-rays originating inside thunderstorms. It has been observed that TGF occurs much less frequently than lightning. However, the TGF generation conditions and mechanism of are not clear, such as why just the TGF-associated lightning produces TGF while others not. Consecutive TGFs detected by space-based platform are usually several seconds to 1-2 minutes apart, and they come from same meteorological environment and even from the same storm cells. This provides a possibility to understand the relationship between lightning and TGF. Based on Fermi high-energy photons observations and the ground low-frequency (LF) lightning sferics measurements, more than 10 pairs of consecutive TGFs with synchronous LF lightning waveform are analyzed. Preliminary results show that the sferics of each TGF pairs are almost same, while they vary with different pairs. More details will be shown. In addition, some TGFs detected by ASIM and the associated lightning will also be introduced.
VQ-VAE generative model of spatial-temporal wildfire propagation
Authors: Cheng Sibo , Arcucci Rossella
Published: March 2024

The growing frequency of wildfires globally has highlighted the importance of immediate fire forecasting. Traditional high-accuracy fire spread simulations, like cellular automata and computational fluid dynamics, are detailed but require extensive computational resources and time. Consequently, there has been a significant push towards developing machine learning-based fire prediction models. These models, while effective, tend to be specific to certain regions and demand a large volume of simulation data for training, leading to considerable computational demands across various ecoregions.In response, this study introduces a generative approach using three-dimensional Vector-Quantized Variational Autoencoders. This method is designed to create spatial-temporal sequences predicting the progression of future wildfires in specific ecoregions. The effectiveness of this model was evaluated in the context of the Chimney fire, a notable recent wildfire in California. The results demonstrate that the model effectively produces realistic and structured fire scenarios, incorporating influential geophysical factors like vegetation and terrain slope. Additionally, the data generated by this model were used to develop and train a surrogate model for wildfire spread prediction. This surrogate model was successfully validated using both simulated data and actual data from the Chimney fire incident.
How can we reduce post-harvest nitrogen losses on agricultural land? Evaluating the potential of easily degradable, nitrogen-free organic soil additives
Authors: Brüggemann Nicolas , Zhao Kerui , Reichel Rüdiger
Published: March 2024

One of the most pressing issues in intensive agriculture is how we can reduce post-harvest losses of nitrogen (N) on agricultural land. In terms of N use efficiency, the focus so far has been on optimizing the amount and timing of N fertilization, including spatially targeted application (precision agriculture). However, we must be aware that this will not be sufficient to solve the problem of N surplus. The mineralization of crop residues and soil organic matter, especially after harvest, can lead to very high mineral N concentrations in the soil, which ultimately result in high N losses, mainly in the form of nitrate leaching, but also as nitrous oxide (N2O) if the excess N is not immobilized before winter. In crop rotations that do not allow the cultivation of a catch crop, e.g. before winter cereals, the N immobilization potential is by far not high enough to immobilize the available mineral N. In this case, a different approach than plant N immobilization is required to immobilize the excess N before winter.Here, we present results from laboratory incubations and field trials with different soils under a wide range of conditions based on the stimulation of microbial biomass growth by readily available organic soil amendments. They show that effective immobilization of mineral N in large quantities (almost 100 % reduction of nitrate concentration in the soil) is possible for several months, even under winter conditions. A consistent picture emerges from the results, suggesting that the optimal and longest-lasting effect of N immobilization can be achieved with nitrogen-free organic compounds that are moderately available to microorganisms (i.e., within several weeks rather than a few days). If the microorganisms are offered compounds that are too readily available (extreme case: glucose), a rapid stimulating effect can be triggered, which, however, does not last long enough to immobilize N for several months due to too early remineralization. If too recalcitrant organic compounds are introduced into the soil, the utilization of the additional carbon source takes too long to lead to effective N immobilization. We can therefore say that we have taken a significant step forward in understanding the mechanisms and timing of microbial N immobilization and remobilization, which may prove key to solving the N surplus problem in agriculture. However, the extent to which such management measures can be implemented in agricultural practice also depends on the political framework conditions that make them economically feasible.
Study of radio emission from a long spark discharge.
Authors: Shlyugaev Yuriy
Published: March 2024

The general characteristics of radio emission from natural lightning discharges have been studied quite well. A detailed study of the radio emission of lightning discharges is associated with certain difficulties arising from the random nature of such events. Much more convenient and informative is the study of radio emission from lightning models - long spark discharges obtained in laboratory experiments. In this case, it is possible to use high-speed photo and video shooting, linking measurements to different stages of the discharge - streamer, leader, through current, return stroke. At the Institute of Applied Physics of the Russian Academy of Sciences, such research is carried out on spark discharges of a meter range in length, created using a Marx generator with a voltage of more than 1 MV. During the work it used the interference protection of measuring systems with autonomous power supply and fiber-optic lines for transmitting data and synchronization signals. The features of radio emission from a long spark are considered and conclusions are formulated on the applicability of laboratory modeling results to studies of the characteristics of natural lightning discharges.