bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing Local Community Vulnerability to Landslides and Floods: A Household Survey Approach in North-Western Rwanda 
Authors: Idukunda Clemence , Michellier Caroline , Twarabamenye Emmanuel , De Longueville Florence , Henry Sabine
Published: March 2024

North-Western Rwanda's hilly and mountainous topography, high elevation, frequent torrential rainfall, and high population density render it highly susceptible to landslides and floods. A comprehensive understanding of community vulnerability to these hazards is crucial for effective risk assessment and mitigation strategies. To address data scarcity in the region, this study is based on a household survey approach that incorporates hazard-specific variables to compare vulnerability across three hazard categories: landslides, floods, and a combination of both. The survey encompasses 904 households across 50 cells (local administrative units), purposively selected according to hazard susceptibility distribution. Principal Component Analysis (PCA) was applied to derive a contextualized Social Vulnerability Index (SoVI). Five principal components accounting for 73.2% of the variance were identified. The first component, contributing 23.4%, highlights the vulnerability associated with unplanned settlements and low income. The second component, representing 19.5% of the variance, emphasizes demographic and social factors. The third component (12.6% of the variance) points to the vulnerability of households solely reliant on agriculture for their income. The fourth component (9% variance) is associated with land ownership, with households lacking land assets experiencing lower vulnerability. The fifth component (8.7% variance) underlines the relevance of household structure variables, indicating the high vulnerability of single-person households. SoVI scores classified 19 cells in the very high or high vulnerability category, predominantly those prone to landslides. These highly vulnerable cells are concentrated in the Northern Province, emphasizing the need to prioritize interventions in this region, such as effective land use planning and livelihood improvement strategies. This study provides a comprehensive vulnerability assessment and valuable insights for prioritizing interventions. The inclusion of hazard-specific variables and a comparative vulnerability approach across areas susceptible to landslides, floods, and both hazard types enhances the specificity and applicability of the findings. These insights are invaluable for local policymakers and disaster prevention and management authorities, enabling them to develop context-specific strategies to improve community resilience and reduce vulnerability to natural hazards.Keywords: Community Vulnerability, Landslides, Floods, Noth-Western Rwanda, Social Vulnerability Index
Water-carbon-sediment synergies and trade-offs: multi-faceted impacts of large-scale ecological restoration in the Middle Yellow River Basin
Authors: Yan Zihan , Wang Taihua , Yang Dawen
Published: March 2024

Ecological Restoration (ER) measures can achieve considerable carbon benefits and reduce sediment loads, concurrently resulting in unintended hydrological consequences. The Middle Yellow River Basin (MYRB), with intensive large-scale ER implementation during the past decades, serves as an excellent case to investigate the concomitant water-carbon-sediment synergies and trade-offs. This study combined a vegetation dynamics simulation scheme and a distributed hydrological model with explicit ER representation to investigate the water-sediment-carbon changes in response to ER in the MYRB. According to the results, ER promoted synergies between carbon sequestration and sediment control and led to improved water use efficiency (WUE). The actual Leaf Area Index and Gross Primary Productivity (GPP) showed improvements in region-averaged values by +0.56 m2 m-2 yr-1 (+7.4%) and +52 gC m-2 yr-1 (+10.9%) compared to those under natural conditions. In the Toudaoguai-Tongguan section which suffered the most serious soil erosion, ER decreased the sediment loads by 11.3×108 ton yr-1 (71.1% of the natural level). Furthermore, WUE changes indicated higher GPP gain per unit evapotranspiration. Meanwhile, trade-offs were also found when taking account of the water yield reduction. During 1982-2019, ER led to significant increases in actual evapotranspiration (+8.3 mm yr-1; +2.2%) and decreases in runoff (-7.6 mm yr-1; -12.7%). Two indicators evaluating the cost-effectiveness of ER, i.e., carbon sequestration and sediment settlement at the cost of per unit runoff decline, remained positive with the average values of 6.12 kgC m-3H2O yr-1 and 0.22 ton m-3H2O yr-1 during 2000-2019, respectively. Nevertheless, both indicators showed downward trends, indicating decreasing marginal benefits brought by ER measures which could have approached the optimal scale in the MYRB.
Integrating Numerical Modeling and Fieldwork for Understanding Land-to-Ocean Litter Transport: A Comprehensive Review
Authors: Oruc Baci Nazife , Santiago-Collazo Félix , Jambeck Jenna R
Published: March 2024

The global issue of marine litter pollution, mainly from land-based sources, has gained significant attention in recent years due to its profound environmental and socio-economic impacts. Environmental impacts pose a significant threat to marine ecosystems, harming marine life through ingestion and entanglement, disrupting habitats, and even introducing harmful chemicals into the food chain. Socio-economically, it affects coastal communities and industries by reducing tourism revenues, damaging fisheries, and increasing cleanup costs, thereby undermining livelihoods and the overall well-being of communities. Furthermore, long-term consequences include potential economic burdens related to public health issues and the need for more extensive waste management systems. This review is a comprehensive overview of the state-of-the-art numerical modeling of land-to-ocean litter transport. It underscores the significance of an integrated approach in addressing this pressing environmental challenge. The focus of this study is exploring the evolving landscape of numerical modeling techniques in the context of hydrodynamics and the significance of fieldwork in enhancing their accuracy in litter transport. Numerical modeling techniques have emerged as powerful tools for simulating complex hydrodynamic processes responsible for litter movement in aquatic environments. For example, Particle Tracing Models (PTMs) have gained prominence in recent years as an effective approach for simulating the trajectory of individual litter particles in aquatic systems by considering various environmental factors, such as currents, tides, and winds. These models enable researchers to assess various scenarios, identify key drivers of litter transport, and develop targeted strategies for litter management and remediation by aiding in predicting their dispersion patterns and arrival locations. However, their effectiveness is significantly enhanced when informed and validated by real-world field data. Fieldwork complements numerical models by providing crucial data for model validation and calibration. It also offers a unique perspective on the real-world challenges and dynamics of land-to-ocean litter transport. Moreover, fieldwork helps identify hotspots of litter accumulation, assess the composition and sources of litter, and understand the influence of local conditions on transport pathways. By combining these approaches, researchers can accurately represent litter transport processes, ultimately aiding in effective litter management and policy development.
Accurate solutions of highly oscillatory systems under large time steps using higher-order phase averages
Authors: Bauer Werner , Cotter Colin J.
Published: March 2024

We introduce a time integrator for a prototype model of highly oscillatory PDEs that exhibits accurate solutions even under the usage of large time step sizes. To achieve large time steps, we apply a phase averaging technique that smooths out the fast waves from the system. To avoid the errors that such smoothing usually entails, we use a higher order (HO) phase averaging algorithm based on the idea of [1]. This algorithm expresses the sensitivity of the solutions on the phases in terms of an HO basis which the equations are projected onto. The resulting HO phase corrections reduce the errors in the solutions even for finite averaging windows. Rather than using monomials as such HO basis as originally suggested in [1], here we introduce an alternative basis in terms of exponentials and we discuss its properties.Similarly to [1], we test this idea on an ODE describing the dynamics of a swinging spring, a model due to Peter Lynch. Although idealized, this model shows an interesting analogy to geophysical flows as it exhibits a high sensitivity of small scale oscillation on the large scale dynamics. On this example, we illustrate that the HO phase averaging method with an exponential basis allows for highly accurate solutions even when using large averaging windows and hence larger time step sizes than standard methods. These HO phase corrections (the reason for this improvement) can be evaluated independently, hence computed in parallel. In contrast, in standard averaging approaches, e.g. [2], arbitrarily accurate solutions could only be obtained with small averaging windows as well as small time step sizes.  We present these highly promising results and discuss challenges in generalizing them to highly oscillatory PDEs for applications in simulations of weather, ocean, and climate.References[1] Bauer, W., Cotter, C. J. and Wingate, B. [2022], Higher order phase averaging for highly oscillatory systems, SIAM Multiscale Modeling \& Simulation (SIAM MMS), 20, 936-956.[2] Peddle, A. G., Haut, T., Wingate, B. [2019], Parareal convergence for oscillatory PDEs with finite time-scale separation. SIAM Journal on Scientific Computing, 41, A3476-A3497.
A modified Voellmy rheology for modeling rock avalanches
Authors: Hergarten Stefan
Published: March 2024

Voellmy's rheology was originally developed for snow avalanches in the 1950s. However, it has also been widely applied to rock avalanches and to debris flows. In its original form, Voellmy's rheology assumes that the effective friction is the sum of Coulomb friction and a velocity-dependent term. While the Coulomb friction term is necessary for letting avalanches stop after a finite time, it causes problems with regard to the long runout of huge rock avalanches. This long runout requires Coulomb friction coefficients much lower than typically assumed for granular media, which finally result in unrealistically smooth morphologies of the deposits. In this presentation, numerical simulations with a recently published modified version of Voellmy's rheology are shown and compared to the conventional version. The modified version assumes two distinct regimes of Coulomb friction and velocity-dependent friction with a transition at a critical velocity derived from the concept of random kinetic energy. The modified rheology explains the long runout of huge rock avalanches without assuming an artificially low Coulomb friction coefficient. Furthermore, it produces hummocky deposit morphologies even with isolated hills similar to toma hills.
Snowpack characterization and depth estimates using UAS-mounted ground penetrating radar: A case study from Western Norway 
Authors: Lee Madeline , Dupuy Bastien , Grøver Arnt
Published: March 2024

There is a visible link between climate change and increased frequency of natural hazards. Avalanches are of particular concern within mountainous and arctic regions. Local snow characterization and mapping is an important first step to forecasting a hazardous event and identify vulnerable regions during risk management assessment of critical infrastructure, such as roadways and tunnels. Information on snow cover and snow properties is also crucial for flood management, hydropower industry and glacier mass balance calculations. 

Uncrewed aerial systems (UASs) play a critical role in safely and efficiently obtaining high-resolution data to characterize snow and ice for avalanche and glacier studies. UASs provide controlled flight altitude and speed and high positioning accuracy resulting in repeatable surveys. Surficial and subsurface information on the snow layers can be obtained depending on the sensor equipped onboard the UAS. Lidar measurements collected prior to and after snow accumulation provide a ground and snow surface maps from which an estimate is derived on snowpack thickness. However, the lidar method does not provide information on internal snowpack structure neither on snow properties. Ground penetrating radar (GPR) allows mapping of the snow surface and insight into subsurface snow layers, depending on the snow characteristics such as snow water equivalent (SWE) and density.  

In March 2023, GPR measurements using a 1GHz antenna were acquired from a commercial off the shelf quadcopter at Fonnbu along the Grasdalen alpine valley, western Norway. Following in-house data processing workflow, two main interfaces are identified through 2D profile picking: rock to snow and snow to air. Intermittent layers are also identified increasing detailed understanding of the snowpack structure. Snow density and velocity are determined using local snowpit logs from which snow thickness is calculated. These snowpack depth estimates are compared with the lidar thickness estimates enabling a multi-scale and -parameter analysis of the Fonnbu snow study site. Methods developed in this study will be implemented for snowpack characterization using UAS-mounted sensors to other study sites within Norway. 
Eco-Enigma Expedition Escape Room - The soils and climate change. 
Authors: Salzedas Elsa , O'Hara Kelly
Published: March 2024

Present an ongoing project named “ Eco-Enigma Expedition Escape Room”. The aim isto an immersive escape room experience designed to raise awareness and promoteaction against climate change. The storyline is about a critical mission, 60 minutes toRescue the Planet. By solving a series of puzzles and challenges within a limitedtimeframe to prevent an impending environmental catastrophe caused by climatechange. Each puzzle/challenge/enigma reveals important pieces of information or/andaction that can help mitigate the crisis. The Escape room is composed by 6 activities,each of then relates action for change the climate or behavior to do it and a specificODS substantiable goal. In each activity, players will collect a code that will be use toopen the door that drove them to a healthy planet. The escape room will be createdwith students from Hight School, given this project a Win-Win situation, not only thehave to investigate, gather information, be creative, reflecting STEAM experientallearning context, and at the same time, we produce a game that can be played by allschool, representing more that 1000 students.
The solar wind in the last solar cycle driven by ADAPT-GONG and GONG magnetograms
Authors: Huang Zhenguang , Toth Gabor , Sachdeva Nishtha , van der Holst Bartholomeus
Published: March 2024

The solar wind variations during a solar cycle are critical in understanding the solar wind acceleration mechanism in different phases of the solar cycle. It is also important in predicting the solar wind distribution in the heliosphere. This problem has been investigated from different aspects, from data analysis to numerical modeling. Previous observations have shown that the distribution of fast and slow wind are different between solar minimum and maximum. In this study, we study the solar wind variations based on a first-principles model, the Alfven Wave Solar atmosphere Model (AWSoM) developed at the University of Michigan. Huang et al. (2023) have used the ADAPT-GONG magnetograms in the last solar cycle to drive the solar wind model and shown that one of the input parameters of the model, the Poynting flux parameter, can be empirically predicted with the open field area. Moreover, they suggested that the average energy deposition rate in the open field regions is approximately constant during a solar cycle. In this study, we use the GONG synoptic magnetograms, and determine if similar conclusions are also valid. We also systematically compare the model performance between the two different input magnetograms.
A new climate impact database using generative AI
Authors: Li Ni , Thiery Wim , Zscheischler Jakob , Messori Gabriele , Guillou Liane , Nivre Joakim , Görnerup Olof , Lampe Seppe , Flynn Clare , Madruga de Brito Mariana , Jezequel Aglae
Published: March 2024

Storms, heat waves, wildfires, floods, and other extreme weather climate-related disasters pose a significant threat to society and ecosystems, which in many cases is being aggravated by climate change. Understanding and quantifying the impacts of extreme weather climate events is thus a crucial scientific and societal challenge. Disaster databases are extremely useful for establishing the link between climate events and socio-economic impacts. However, publicly available data on impacts is generally scarce. Apart from existing open disaster databases such as EM-DAT, robust data on the impacts of climate extremes can also be found in textual documents, such as newspapers, reports and Wikipedia articles. Here we present a new climate impact database that has been built based on multiple public textual entries using a pipeline of data cleaning, key information extraction and validation. In particular, we constructed the database by using the state-of-the-art generative artificial intelligence language models GPT4, Llama2 and other advanced natural language processing techniques. We note that our dataset contains more records in the early time period of 1900-1960 and in specific areas such as than the benchmark database EM-DAT. Our research highlights the opportunities of natural language processing to collect data on climate impacts, which can complement existing open impact datasets to provide a more robust information on the impacts of weather and climate events.
Evaluation of the chemistry and climate impact of the new solar forcing dataset for CMIP7 using the Whole Atmosphere Community Climate Model
Authors: Kinnison Douglas , Marsh Daniel , Tilmes Simone
Published: March 2024

The solar forcing dataset prepared for the 6th round of the Coupled Model Intercomparison Project (CMIP6) has been used extensively in climate model experiments. Recently, an International Space Science Institute (ISSI) Working Group was established to revisit the solar forcing recommendations in order to define a roadmap for building a revised solar forcing dataset for the upcoming 7th round of CMIP (Funke et al., 2023). This new dataset will introduce changes in the radiative forcing of climate either directly, or indirectly via changes in atmospheric composition. In CMIP6, the solar forcing consisted of both a total solar irradiance (TSI), along with a spectrally resolved solar irradiance (SSI). The TSI for solar minimum was set to 1360.8±0.5Wm-2 and the SSI covered the 10nm to 100mm spectral region. A similar approach is proposed for CMIP7 except for two major aspects of the reconstruction: 1) the definition of the reference spectrum for the quite Sun; 2) the temporal variability. The major difference between the proposed CMIP7 SSI quite sun reference spectrum and that used for CMIP6 is the spectral shape. The new SSI spectrum has an irradiance that is 1-5% higher in the visible band and lower by 1-2% in the Near-IR wavelength range (1000-2000nm). The solar temporal variability in the CMIP6 and CMIP7 reconstructions are based on both the NRLSSI2 and SATIRE reconstructions. These reconstructions have been improved in preparation for CMIP7 and the aim is for both reconstructions to use the same reference spectrum and be driven by the same solar proxies. In this work we used the Whole Atmosphere Community Climate Model (WACCM) to examine the chemical and climate implications of the proposed CMIP7 solar forcing updates compared to the CMIP6 approach. WACCM is a chemistry-climate model that extends from the surface to 140km. The horizontal resolution is ~1degree. WACCM has a detailed representation of chemical and dynamical processes from the troposphere through the lower thermosphere. We examined the “chemical only” impacts of the solar forcing choice by running WACCM in the specified dynamics mode using NASA Modern-Era Retrospective analysis for Research and Applications Version 2 (MERRA2). The “climate” impacts were derived by running the model with interactive dynamics coupled to a deep ocean. Conclusions from this work will support the development of the next version of WACCM for participation in the CMIP7 assessment.Funke, B., Dudok de Wit, T., Ermolli, I., Haberreiter, M., Kinnison, D., Marsh, D., Nesse, H., Seppälä, A., Sinnhuber, M., and Usoskin, I.: Towards the definition of a solar forcing dataset for CMIP7, Geosci. Model Dev. Discuss. https://doi.org/10.5194/gmd-2023-100. 
Canada’s Wildfire Susceptibility Assessment Using Statistical Data-Driven Models
Authors: Khosravi Khabat , Farooque Aitazaz
Published: March 2024

AbstractWildfire Susceptibility Assessment (WSA) is one of the critical approaches to wildfire risk management. In this study, we employed a hybrid approach by integrating two distinct statistical models, namely Frequency Ratio (FR), Weight of Evidence (WoE), with Shannon Entropy (SE) (i.e., FR-SE and WoE-SE) for WSA. To meet the aim, 18538 historical wildfire data were collected and separated into two sections for model development and validation. Next, 13 wildfire-influencing parameters, including slope degree, aspect, topographic wetness index, elevation, evapotranspiration, land use/land cover, normalized differences vegetation index, distance from the lake, precipitation, distance from the rivers, distance from the roads, soil moisture, and mean annual maximum temperature were prepared and feed the models. Finally, model performance were evaluated using the validation data set and receiver operating characteristic (ROC) curve technique. Findings shows that the integration of models has improved the modeling performance, as WOE-SE model has the highest performance (96.5%), followed by WoE (96.3%), SE-RF (95.9%) and RF (95.2%) model respectively. Result of SE model showed that mean annual maximum temperature has the highest impact on the wildfire occurrence across Canada, while topographic wetness index is the lowest effective parameter.Keywords: Wildfire, statistical models, Canada, Shannon Entropy, Frequency ratio, Weight of Evidence.
Overland flow and shallow subsurface flow generation in a small pre-Alpine catchment: insights from tracer experiments
Authors: Leuteritz Anna , Gauthier Victor , van Meerveld Ilja
Published: March 2024

Near-surface flow pathways are important runoff processes in humid catchments with low permeability soils and provide fast transport of water and solutes from the hillslopes to the stream network. To improve our understanding of the spatial variability in solute transport and mixing in overland flow and shallow subsurface flow, we conducted tracer experiments on trenched runoff plots in a small headwater catchment underlain by Gleysols in the Swiss pre-Alps.We applied a line of NaCl tracer to the surface of 14 small (3 m2) runoff plots and continuously measured flow rates and electrical conductivity in overland flow and shallow subsurface flow during natural rainfall events. In addition, we conducted tracer experiments during artificial rainfall on two large (>80 m2) trenched plots. Uranine and NaCl were applied as a line tracer at various distances from the trench after overland flow and subsurface flow had reached a steady state. NaBr was applied into the subsurface (at ~20 cm depth) and deuterium-enriched water was applied via the sprinklers. Samples of overland flow and shallow subsurface flow were collected at intervals ranging from 1 minute to 1 hour during several hours. We also continuously measured the rainfall rate, flow rates and electrical conductivity of overland flow and shallow subsurface flow, and soil moisture content.The breakthrough curves from the small-scale experiments highlight the high spatial variation in overland flow and subsurface flow generation across the catchment, and the importance of mixing with shallow soil water for both overland flow and shallow subsurface flow. The results of the big plot experiments confirm the significant mixing of overland flow and subsurface flow. Maximum velocities, calculated from the first arrival of the tracers, were very high and ranged from 6x10-3 to 2x10-2 m s-1 for overland flow and 3x10-3 to 1x10-2 m s-1 for subsurface flow. Runoff generation in the large mixed forest plot was faster than for the large grassland plot and occurred primarily via macropores and soil pipes. In contrast, at the large meadow plot solute transport appears to be dominated by flow through the soil matrix.
Shifting potential for high-resolution climate reconstructions under global warming
Authors: Jevšenak Jernej , Buras Allan , Babst Flurin
Published: March 2024

Tree-ring based reconstructions of climate in pre-instrumental times render a cornerstone of earth-system science and critically rely on statistical relationships between meteorological observations and natural proxy archives. Recent studies have frequently reported that these relationships are not stable in time (non-stationarity), possibly caused by global change (climate, atmospheric CO2), data resolution and quality, and statistical methods applied. Here, we assess the elusive impacts of these factors on the palaeoclimatological potential across the Northern Hemisphere. Scrutinizing spatiotemporal patterns in widely applied validation metrics derived from 3,781 tree-ring chronologies and 517 published dendroclimatic studies, we show that temperature and precipitation sensitivity have increased in the late 20th century. This increase was consistent with trends derived from our meta-analysis. Projecting our results into climate scenarios for the 2021-2040 period indicated further expansion of areas with strong water limitation (+5±2%), whereas the areas with strong temperature limitation were projected to shrink by 8±3% (tree-ring width proxy) and 3±2% (maximum latewood density proxy). Moreover, under increased atmospheric CO2 concentrations and consequently water-use efficiency, water limitation on tree growth may weaken and so the sensitivity to precipitation with consequences for corresponding reconstructions. These spatiotemporal shifts in the climate response of tree growth indicate that continued climate change over the next decades will substantially alter our capacity to establish a robust historical baseline for climate change research. However, our assessment of 517 published climate reconstructions revealed that scientists have, so far, successfully conserved climate signals in trees through refined statistical approaches. But we deem it unlikely that methodological advances will continue to compensate for projected weakening temperature correlations, which will pose a daunting challenge for future temperature reconstructions based on TRW records. Encouragingly, despite minor decreases in projected climate sensitivity, MXD is expected to remain a strong temperature proxy. High-resolution paleoclimatology will thus need new innovations to ensure its continued support of earth system science. Lastly, a better understanding of tree growth response to environmental changes is crucial for accurately addressing non-stationarity in climate reconstructions.Jevšenak, J., Buras, A., Babst, F., 2024. Shifting potential for high-resolution climate reconstructions under global warming. Quaternary Science Reviews 325, 108486.
Impact of Parameters Related to Ice Crystal on the Simulation of Winter Precipitation over the Korean Peninsula
Authors: Kim Ki-Byung , Lim Kyo-Sun Sunny
Published: March 2024

Cloud microphysics parameterization has several ice-crystal-related parameters that define the characteristic of ice crystal. Weather Research and Forecasting (WRF) Double-Moment 6-class (WDM6) parameterization scheme adopts the fall velocity-diameter and mass-diameter relationships from Heymsfield and Iaquinta (2000, HI00 hereafter) with the assumed single-bullet shape of ice crystals, and the mean mass-weighted terminal velocity-mixing ratio relationship from Heymsfield and Donner (1990, HD90 hereafter). There are a total five parameters that define ice-crystal characteristics, and these parameters vary according to different shapes of ice crystals, contributing to uncertainties of simulated precipitation. To assess these uncertainties, we generate 50 sampling sets using Latin hypercube sampling within the recommended range from previous studies. Numerical experiments are conducted for two major types of winter precipitation, namely Air-mass Transformation (AT) and Ease-coast Terrain effect (ET) types, over the Korean peninsula. The simulation results indicate that parameters defining the mass-diameter relationship are most sensitive for simulating precipitation in the AT type, while parameters defining the fall velocity-diameter relationship are most sensitive for the ET type. Sensitivity experiments are designed by adjusting the sensitive parameters for each type by ±20% to mitigate biases in surface precipitation observed in the control experiments. In the AT type, the sensitivity experiment simulates more solid-phase precipitable hydrometeors, such as snow and graupel, resulting in increased precipitation over the region with a negative bias. Conversely, in the ET type, the sensitivity experiment reduces the amount of snow and graupel, leading to a decrease in precipitation over the area with a positive bias. Our analysis underscores the high priority of tuning parameters related to ice-crystal characteristics to reduce uncertainty in precipitation simulations, depending on the type of winter precipitation. Key words: Ice crystal, Uncertainty parameter, WDM6, Winter precipitation Acknowledgement: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (RS-2023-00272424) and Korea Meteorological Administration Research and Development Program under Grant (RS-2023-00240346)
Wave statistics and spectral shape in the nearshore region
Authors: Gemmrich Johannes
Published: March 2024

Human interaction with ocean surface waves occurs mainly in the nearshore region. Waves propagating towards the coast over gradually sloping bathymetry undergo fundamental transformations, resulting in statistics and spectral energy distributions that are substantially different to those of the incoming wave field in deep water. This is of particular importance to the generation of individual extreme waves.This presentation will address our recent observational studies of spectral wave properties and surface elevation statistics at various nearshore locations ranging from normalized water depth of kH > 5 (deep water) to kH < 0.1 (beach-water interface). Data were obtained by surface following wave buoys, bottom-mounted pressure sensors, and an acoustic current profiler. The data reveal the dependence of skewness, kurtosis, and wave groupiness on normalized water depth, and on the position within the surf zone relative to the onset of depth-induced breaking. In the surf zone, skewness and groupiness are modulated coherently, whereas modulations of the kurtosis seem to be more random. In addition, the spectral change of the wave energy across the surf zone including the emerging infragravity wave signal will be discussed.
Tropical-polar teleconnections: Impacts of North Atlantic meltwater forcing on the Indian Ocean
Authors: Tiger Benjamin H. , McGee David , Ummenhofer Caroline
Published: March 2024

Across all future IPCC Shared Socioeconomic Pathways, the strength of the Atlantic Meridional Overturning Circulation (AMOC) is projected to decline. However, there is much less certainty about the impacts of AMOC decline further afield. Evidence from paleoclimate archives and simulations suggests eastern African monsoons weakened under periods of high meltwater forcing in the North Atlantic, particularly during the most recent deglaciation. To explore the dynamics of this high- to low-latitude teleconnection, we use a compilation of ~30 sea surface temperature (SST) records from the tropical Indian Ocean spanning the last 30 ka. The zonal Indian Ocean SST gradient calculated from this compilation shows a remarkable similarity with North Atlantic 231Pa/230Th records of AMOC strength, particularly during intervals of variable meltwater forcing such as the Younger Dryas, Bølling-Allerød, and Heinrich stadials. A weaker AMOC is associated with cooler western Indian Ocean and a warmer eastern Indian Ocean, suggesting a tight linkage between AMOC strength and zonal Indian Ocean variability. To better understand this teleconnection, we analyzed a meltwater single-forcing scenario from a transient simulation of the Last Glacial Maximum to present (TraCE, 22ka-0ka). Under simulated meltwater forcing events, the tropical zonal Indian Ocean SST gradient intensifies (i.e., relative cooling in the west and warming in the east), in agreement with SST paleorecords. This response stems from an intensification of the subtropical high over Southern Europe which drives northerly surface wind anomalies across Arabia and the Horn of Africa, with cooler Northern Hemisphere anomalies extending as far south as Madagascar. This cools the surface western Indian Ocean, particularly in the Arabian Sea, enhancing the Bjerknes feedback and strengthening the Walker circulation across the basin. This effect is strongest in austral summer (DJF) when the Somali Jet reverses and northerly winds advect cool northern air into the deep tropics. Anomalous northerly winds and western Indian Ocean cooling were also found to be common feature of eight hosing experiments under preindustrial boundary conditions from the North Atlantic Hosing Model Intercomparison Project (NAHosMIP). Overall, we hypothesize an atmospheric mechanism connecting the high-latitude North Atlantic and tropical Indian Ocean under meltwater forcing, with the western Indian Ocean playing an outsized role in steepening the zonal SST gradient across the basin which weakens monsoon systems in eastern Africa.
Influence of geometry, grid resolution, initial conditions and hydraulic soil parameters for the integrated coupled hydrological model Parflow-CLM
Authors: Muñoz-Vega Edinsson , Bogena Heye , Schulz Stephan
Published: March 2024

In this work, the parallel and fully integrated coupled hydrologic model Parflow-CLM was used to simulate the water and energy fluxes in a 4.2 km2 mountainous headwater catchment in the Odenwald, Germany, for a period of three years at hourly resolution. First, to establish the most time-efficient configuration of the model able to describe the observed discharges of the catchment, different definitions of the numerical domain for a fixed set of parameters along with different horizontal and vertical grid resolutions were compared. Second, with the purpose of achieving a calibrated state of the model, hydraulic soil parameters such as saturated hydraulic conductivities, Van Genuchten parameters, Manning coefficients, and anisotropy factors were optimized. In addition, the influence of the spin-up period was investigated, whereby an spin-up period of eight years was required for each simulation, despite the high computational effort involved, as the different model configurations result in different initial conditions. Finally, computational efforts, subsurface and surface storages, and statistical error measurements related to observed streamflow will be presented, aiming to provide some recommendations to the community about the required complexity for the calibration of complex integrated hydrological models.
Local variations in lithology, thermal conditions and redox state control mechanisms of carbon storage and release in the continental mantle
Authors: Jacob Dorrit , Chen Chunfei , Foley Stephen
Published: March 2024

The continental lithosphere is an enormous reservoir for carbon, but its sequestration and release over geological time are poorly understood. Recent advances indicate that estimates of the amount of carbon released by gradual degassing from the mantle need to be revised upwards, whereas the carbon supplied by plumes may have been overestimated in the past. Variations in rock types and oxidation state may be very local, exerting strong influences on carbon storage and release mechanisms. Deep subduction of thick sedimentary packages may be prevented by diapirism, whereas thinner sequences may be subducted. Carbonates stored in the transition zone melt when they heat up, a process which is recognised by coupled stable isotope systems (e.g. Mg, Zn, Ca). There is no uniform “mantle oxygen fugacity”, and heterogeneous oxidation conditions are likely to exist, particularly at the thermal boundary layer and in the lowermost lithosphere where very local mixtures of rock types coexist. The infiltration of carbonate-rich melts from either subduction or melting of the uppermost asthenosphere leads to trapping of carbon by redox freezing or as carbonate-rich dykes in this zone. Deeply-derived, reduced melts may form additional diamond reservoirs, recognised as polycrystalline diamonds associated with websteritic silicate minerals.Carbon is released by either edge-driven convection, which tears down sections of the thermal boundary layer and lower lithosphere so that they melt by a mixture of heating and oxidation, or by lateral advection of solids beneath rifts. Both mechanisms are concentrated at changes in lithosphere thickness and result in carbonate-rich melts, explaining the spatial association of craton edges and carbonate-rich magmatism. High-pressure experiments on individual rock types, and increasingly on reactions between rocks and melts, are fine-tuning our understanding of processes and providing unexpected results that are not seen in experiments on single rocks. Future research should concentrate on elucidating local variations and integrating these with the interpretation of geophysical signals. Global concepts such as average sediment compositions and a uniform mantle oxidation state are not appropriate models for small scale processes; an increased focus on local variations will help to refine carbon budget models.
Active tectonics within the southwestern edge of the Fars Arc, SW Iran
Authors: Fathian Aram , Koyi Hemin , Back Stefan , Nazari Hamid , H. Shugar Dan , Shokri Mohammad Ali , Reicherter Klaus
Published: March 2024

The Fars Arc constitutes the southeastern segment of a tectonic recessions and salients array that characterizes the Zagros orogen. The delineation of the Fars Arc's western boundary is attributed to the prominent Kazerun fault system. However, further to the west, the southwestern periphery of the Arc (i.e., the Bushehr area) remains relatively unexplored, lacking documented evidence of tectonically active structures, as well as significant historical and instrumental seismic events. We combined tectonic geomorphology, remote sensing, and Quaternary geochronology to comprehensively study and identify tectonically active structures within the onshore area. Investigating the offshore area, we utilized 2D seismic-reflection data to interpret and image active subsurface structures in the Persian Gulf. We mapped and introduced several active faults in the Bushehr area, some of which are closely associated with active Quaternary anticlines, e.g., the Bushehr and Abtavil anticlines. Two generations of uplifted marine terraces, Terrace-I and Terrace-II across the Bushehr anticline, reveal a local uplift rate of approximately 0.8 mm/yr across the Bushehr Peninsula. The offshore 2D seismic-reflection data indicate ongoing deformation in the study area and show evidence of a recent sedimentary depocenter offshore of the Bushehr Peninsula. These observations define the present-day active deforming structures along the Zagros orogenic front in the Persian Gulf. The 2D seismic-reflection interpretations have characterized the active folding of the Bushehr anticline, indicating a minimum age of approximately 600 ka BP. The integration of on- and offshore geological analysis has revealed contemporaneous incipient deformation and syn-kinematic sedimentation, which significantly contributes to our understanding of geodynamics of the Zagros deformation front.
Critical metals distribution in Bauxite Residues: a Compositional Data Analysis approach
Authors: Ameur-Zaimeche Ouafi , Kechiched Rabah , Mameli Paola , Mesto Ernesto , Mongelli Giovanni , Oulad mansour Abdelhamid , Schingaro Emanuela
Published: March 2024

This research explores the major element control on the distribution of critical metals (CM) in red muds (RM), the residues of the Bayer process developed on bauxite ore, sampled at the Porto Vesme disposal site, Sardinia, Italy. RM represent an environmental challenge due to their high alkalinity and storage issues. The relationships between major elements and CM were assessed by Compositional Data Analysis (CoDa).X-ray powder diffraction (XRPD) revealed predominant minerals including hematite, gibbsite, boehmite, anatase, cancrinite, sodalite, and quartz, consistent with previous studies on RM from the same site (Castaldi et al., 2008; Mombelli et al., 2019). Inductively Coupled Plasma Mass Spectrometry (ICP-MS) assessment reported the major oxides composition (wt %): SiO2 (11.9 – 22.6), Al2O3 (17.4 – 24.9), Fe2O3 (22.2 – 30.3), MgO (0.7 – 4.7), CaO (2.6 – 5.9), Na2O (3.5 – 11.5), K2O (0.2 – 0.7). Iron content averaged at 25.8 wt%, underscoring i considerable presence of iron in bauxite residues, while alumina averaged at 20.75 wt% is consistent with the large amount of Al-hydroxides detected by XRPD. Among CM, specifically the LREE, the Ce abundance (93 – 258 ppm) is a notable feature.CoDa involved Principal Component Analysis after a transformation of raw data into centred log ratio. The PC1 and PC2 association revealed significant influence from TiO2 and Na2O on critical metals such as HREE, LREE, Sc, and Co. Noteworthy is the Bayer process involving high-temperature pressure leaching of bauxite ores with sodium hydroxide solution for the Al recovery, leaving TiO2 in the resulting residue. Other CM, such as V and Ga, are predominantly controlled by MgO.This preliminary study suggests that RM could be a promising geo-material for a strategic CM recovery and efficiently reusing the secondary byproduct, providing a sustainable and environmentally friendly alternative to its mere disposal (Liu and Naidu, 2014).
Visualization technique in a laboratory experiment for the deformation distributions of subsidence of aquitard over aquifer due to excess pumping
Authors: Tabe Kazunori , Aichi Masaatsu
Published: March 2024

Visualization methods using transparent synthetic soils (TSS) have been developed as a physical model of macroscopic soil behavior from a geotechnical engineering perspective. Transparent surrogates containing transparent porous media and pore fluids have been used to simulate the geotechnical properties of natural soils. Studies to experimentally verify local deformation in subsidence phenomena require the use of inexpensive laboratory industrial materials to understand the macroscopic scale of larger test models. TSS made of polymeric polymers used in this experiment are one of those employed to accomplish this need and are easy to handle.In the present study, a larger-scale pumping test than previously reported was conducted using a 300 mm wide x 250 mm long x 249 mm high acrylic tank filled with transparent hydrated polymer to represent an aquitard (clay layer) over an aquifer (saturated silica sand). Settlement within the synthetic clay layer due to pumping of pore water from the silica sand was constantly monitored by the target racking method using 100 particles of 3 mm diameter immersed in the synthetic clay layer. This experiment successfully visualized the deformation inside TSS due to vertical propagation of pore water pressure in the TSS during pumping and after pumping, in more detail than in the previous experiment. The experimental results showed good agreement with the numerical results of the three-dimensional pore-plastic deformation theory.
Missing OH reactivity contributed by photochemical reactions cause uncertainty to ozone production in AQUAS campaigns in Japan
Authors: Li Jiaru , Sakamoto Yosuke , Kohno Nanase , Murano Kentaro , Kajii Yoshizumi
Published: March 2024

Tropospheric ozone is harmful to human and the ecosystem, which is by-product of the reaction of OH with VOCs and NOx. Field campaign is an effective way to assess regional air quality and the detection of OH reactivity provides a top-down approach to understand the general existence of trace species under specific conditions. Concurrent trace species measurement as bottom-up approach gives information on the detailed atmospheric chemistry. We have conducted Air QUAlity Study (AQUAS) campaigns in different sites in Japan over years and explored the missing OH reactivity contributed by unknown trace species that equals to the discrepancy between top-down total OH reactivity and bottom-up calculated OH reactivity. The investigation of missing OH reactivity in field campaigns showed potential contribution from secondary products. Unconsidered missing OH reactivity on ozone production sensitivity will lead underestimation to ozone production potential and overestimation to VOC-limited regime. In addition, field observations at the same site and varied years such as before and after the corona virus (COVID-19) pandemic can also shed light on the reduction of anthropogenic emission, which should be meaningful for a low emission future society. Missing trace species and unconsidered photochemistry in several field campaigns in Japan will be compared in detail and their role should be considered to make effective air quality policies.Acknowledgement: We acknowledge all collaborators on each of the field campaigns specifically our debts to Dr. Yasuhiro Sadanaga, Dr. Kei Sato, Dr Shungo Kato, and Dr. Yoshihiro Nakashima.
Assessing impacts of Earth system tipping points on human societies 
Authors: Betts Richard , Dyke James , Fuller Elizabeth , Jackson Laura , Laybourn-Langton Laurie , Steinert Norman , Xu Yangyang
Published: March 2024

Assessments of climate change effects on humans and ecosystems have previously included only limited information on the consequences of climate tipping points. While some national evaluations have touched on tipping point implications, assessment has been largely qualitative, with minimal quantitative analysis. Understanding and quantification of impacts of tipping points is recognised as a significant knowledge gap, and improving the research base in this area is essential for climate risks to be fully evaluated.This presentation examines the current knowledge of Earth system tipping point impacts on people, exploring the evidence on impacts from individual tipping points, and assessing specific sectors and their vulnerability to these tipping points. Localised effects arise when climate tipping points, such as permafrost thaw and forest dieback, are crossed. These effects stem from land surface changes and alterations in regional climates and weather extremes. Global impacts manifest through large-scale shifts in atmospheric and oceanic circulations, altering global warming rates and sea level rise. Oceanic dynamics, like collapse of the Atlantic Meridional Overturning Circulation, can reshape regional climates and cause widespread shifts in temperature and precipitation patterns. Similarly, cryospheric tipping points, such as marine ice cliff collapse, have the potential to accelerate sea level rise, affecting flooding hazards like coastal inundation. Biosphere tipping points, such as Amazon dieback, intensify greenhouse gas concentrations, hastening global warming and its associated extreme weather events, regional climate shifts and sea level rise.All these have the potential to impact the security of water, food and energy, human health, ecosystem services, communities and economies. The body of evidence varies across tipping points and sectors, but the implications for profound impacts across all areas of human society are clear.