bluuebunny/crossref_metadata_2025 huggingface dataset:
Ozone pollution mitigation under China’s ‘Dual-Carbon’ scenario over the Guangdong-Hong Kong-Macao Greater Bay Area
Authors: Li Danyang , Ye Xingpei , Zhang Lin , Liu Xiaorui , Guo Chaoyi , Wu Kai , Dai Hancheng
Published: March 2024

As greenhouse gases and air pollutants are often co-emitted, the co-benefits on air quality improvement arising from implementing low-carbon policies are drawing much attention. Here we focus our research on the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) in south-eastern China, the demonstration zone for air pollution prevention and control initiatives of China, while still contending with severe ozone pollution, particularly in autumn. This study assesses whether China’s ‘Dual-Carbon’ targets contribute to the GBA achieving the national ozone control goals and offers corresponding mitigation strategies. We developed an external module to softly couple an integrated assessment model IMEDCGE (Integrated Model of Energy, Environment, and Economy for Sustainable Development, Computable General Equilibrium) with the WRF-Chem atmospheric chemistry transport model. The fusion allows us to project the regional ozone pollution evolutions from the base year (2015) to 2050 under various future scenarios. We explore three anthropogenic emission reduction pathways, each reflecting different levels in climate change mitigation targets and end-of-pipe control policies, resulting in varied ozone precursor reduction patterns. The results show that implementing China’s ‘Dual-Carbon’ policies, combined with stringent end-of-pipe control measures, will substantially decrease the averaged MDA8 surface ozone across the GBA to below 90 μg m-3 by 2050. However, different ozone concentration trends emerge between the southern and northern regions due to spatial variations in ozone chemical regimes, as indicated by H2O2/HNO3 ratios. Overall, NOx emission reduction will become increasingly effective in curbing ozone pollution till 2050, while NMVOCs emission reduction, driven by strict end-of-pipe control policies, plays a pivotal role in the short term (before 2030). Even under the most ideal scenario, where more than 90% of local anthropogenic NOx and 85% of NMVOCs emissions are eliminated, our findings underscore the imperative of coordinated efforts across all sectors and collaborative emission reduction beyond the GBA to mitigate ozone pollution effectively.
Global FLUXNET Datasets: Past Usage, Opportunities, and New Data
Authors: Pastorello Gilberto , Beringer Jason , Durden David , Trotta Carlo , Cheah You-Wei , Isaac Peter , Sturtevant Cove , Papale Dario
Published: March 2024

Widely used in studies ranging from ecophysiology dynamics to global estimates using models and remote sensing data, FLUXNET datasets have become key to scientific research and applications. More frequently updated and high-quality FLUXNET data collections are ever more pressing, serving opportunities with new technologies and new real-world applications including nature-based and technological climate solutions, carbon credit verification, support to agriculture decision systems, and ecological forecasting. The three major FLUXNET releases (FLUXNET2015, LaThuile in 2007, and Marconi 2000) have been widely used by the scientific community, academia and industry. Nonetheless, release cycles of 7-10 years have become a major limiting factor, given the demand for continuously updated collections for anchoring remote sensing (calibration and validation), models (from hindcasts to forecasting), and real-world applications requiring near-real-time data. Regional flux networks have sought to expand the datasets by increasing the number of sites, variables and metadata shared, by improving data quality, and by moving toward open data principles via the recent adoption of the CC-BY data license. New network-level data products are being released, either regularly (e.g., AmeriFlux, ICOS, NEON, TERN datasets), or in response to specific demands (e.g. Drought2018 and WarmWinter2020 in ICOS). These data are processed using the shared and jointly maintained ONEFlux pipeline, making data products fully compatible and interoperable. However, mechanisms for global access to regional network data at a global scale are still challenging for users. The continuous development of the FAIRness and related data discovery tools further supports new strategies to create, maintain, and continuously update FLUXNET datasets. At the same time, inequity in data use, credit, recognition, and contribution is still a significant challenge that must be highlighted and solved. Here, we present a roadmap for how future FLUXNET synthesis datasets can be constructed and shared. We demonstrate a data discovery and access tool, look into benefits for data providers and users, and highlight data usage and availability. Open discussion of these challenges and solutions is encouraged.https://shuttle-demo.fluxnet.org/
Caspian Sea Level Changes and Coastal Dynamics: A Case Study of the Gizil-Aghaj State Reserve Using Multi-Sensor Satellite Data
Authors: Ahadov Bahruz , Kadirov Fakhraddin , Fielding Eric Jameson
Published: March 2024

The decreasing sea level of the Caspian Sea is having a serious impact on coastal ecosystems and biodiversity. This study, conducted over a decade from 2014 to 2023, provides a comprehensive analysis of the coastal transformations in the Gizil-Aghaj State Reserve, Azerbaijan, using remote sensing technologies. By utilizing a combination of optical and radar satellite data, we mapped the evolving interplay between land and sea. Our research reveals a significant coastline shift, with the Caspian Sea receding to expose an additional 218 km2 of land. This significant change was most apparent in the northeastern area, corresponding with regions experiencing substantial land subsidence. As the Caspian Sea's level decreases and the land sinks simultaneously, it's reasonable to expect that the shoreline would remain stable. In contrast to areas with land subsidence, places where the land is uplifting, along with the Caspian Sea's decreasing level, are likely to experience noticeable changes in their shoreline, suggesting a more dynamic and changing coastal area. These findings are crucial for understanding the fluctuations in the Caspian Sea level, likely influenced by a combination of natural geological processes, human activities, and broader climatic trends. The subsidence observed in some areas may be due to tectonic movements or human activities such as resource extraction. In difference, the uplift seen in other areas, where there is evidence of building up over time, might be influenced by both anthropogenic factors and natural tectonic processes. Moreover, our study highlights the intricate relationship between coastal dynamics, vertical land movements, and environmental changes. It highlights the critical need for integrated and multi-dimensional monitoring approaches to address these complex interactions. These results not only contribute to a deeper understanding of the Gizil-Aghaj State Reserve's coastal ecosystem but also offer valuable perspectives on the Caspian Sea's response to climate change. Such insights are crucial for developing adaptive strategies for coastal management and conservation in an era marked by environmental uncertainties and changes.
Speleothems as archives for terrestrial dissolved organic carbon export – a radiocarbon perspective
Authors: Lechleitner Franziska , Rowan Sarah , Xue Gang , Guidobaldi Giulia , Huber Tim
Published: March 2024

Terrestrial ecosystems are one of the Earth's largest active carbon reservoirs and hold three times more carbon than the atmosphere. However, their sensitivity and response to global climate change remain debated and may be dependent on multiple processes acting on different spatial and temporal scales.Speleothems, secondary cave carbonate deposits, offer a unique, but under-exploited opportunity to reconstruct the export of dissolved carbon species at the local to regional scale. In this context, radiocarbon is the proxy of choice to unveil the dynamics of the carbon cycle, as it can give information on reservoir turnover times and mixing ratios between different carbon sources. We use an approach consisting in the extraction and isotopic analysis (14C and δ13C) of non-purgeable organic carbon extracts from speleothems, which gives us insight into dissolved organic carbon (DOC) export from the surface. Such observations, especially over periods of rapid climate change exceeding present-day variability, could be invaluable to better constrain the sensitivity of carbon export fluxes to environmental and climatic changes.In this contribution, we will review the progress our group has made over the past years in methodological advances that allow us to develop reproducible and precise DOC reconstructions based on trace amounts of organic matter incorporated in speleothems. We show that, while strongly driven by local conditions, speleothems do retain information on the dynamics and export of DOC from the terrestrial biosphere, and discuss best steps and practices to achieve reliable results.
Nonlinear least-squares solution for the multi-station stacking problem in realizing a terrestrial reference frame
Authors: Hu Yu , Fang Xing , Zeng Wenxian
Published: March 2024

Multi-station (or time series) stacking is a fundamental task in the realization of a terrestrial reference frame (TRF), which is, however, rank-deficient in nature due to the arbitrarily selected target frame. In practice, such a model is approximated as a linear form and the classical free network theory is applied. It is known that the one-step adjustment only works in cases where the nonlinearity (measured by curvature) is moderate, and the initial point is very good; for TRF, it requires the deformable networks with a small enough time span for the network shape to be nearly unaltered. However, these assumptions can be nullified for the cases such as large time span and the integration of some local survey results. To address these limitations, we propose to solve the geodetically meaningful and numerically exact least-squares (LS) solution for the multi-station stacking model. The contributions are summarized as follows:The original nonlinear LS objective for the multi-station stacking model is investigated and its characteristics are analyzed;
The nonlinear Baarda’s S-transformation is formulated for such a problem, which transforms different LS solutions that share the same network configuration;
Two ways to obtain the geodetically meaningful solution are proposed, i.e., the minimally-constrained solution and the nearest-solution, where the latter originates from the inner-constraint solution in the linear case.
The iterative schemes to obtain the two types of solutions are derived, which are shown to be essentially the truncated Gauss-Newton method. In addition, some techniques such as finite differences are employed to enhance numerical stability.
The developed theory is verified by the real examples.
The role of poroelasticity in rupture dynamics across fault stepovers
Authors: Huang Luyuan , Dal Zilio Luca , Rafn Heimisson Elías
Published: March 2024

Understanding earthquake rupture propagation across fault stepovers is pivotal for assessing the seismic hazard, offering vital insights into dynamic rupture processes within intricate fault geometries. However, the role of poroelastic effects within strike-slip fault systems featuring stepovers remains unexplored in dynamic models simulating Sequences of Earthquakes and Aseismic Slip (SEAS). Many existing models neglect poroelastic effects, and among those that consider them, a typical standard value of 0.8 is adopted for Skempton's coefficient B. Furthermore, a single dynamic rupture simulation is unable to address the frequency at which ruptures propagate through the stepover. Instead, these simulations only provide a binary status, indicating whether the ruptures jump or arrest. Thus, the investigation into how poroelasticity influences the likelihood of an earthquake jumping through a stepover emerges as a significant area of study. In response, we introduce a quasi-dynamic boundary element model that simulates 2D plane-strain earthquake sequences. This model incorporates undrained pore pressure responses affecting the fault's clamping and unclamping mechanisms and is governed by rate-and-state friction, with state evolution defined by the aging law. We first illustrate that dynamic rupture occurring in either left-lateral or right-lateral fault stepovers leads to a dynamic decrease (unclamping) or increase (clamping) in the effective normal stress. Dynamic variations of the effective normal stress depend on Skempton's coefficient. Consequently, higher Skempton's coefficients can promote rupture jumping across fault segments even for larger stepover distances. We then conduct a thorough parameter space study, evaluating the effects of Skempton's coefficient variations and stepover width on fault interactions within a fluid-filled porous environment. The likelihood of rupture jumping involves a trade-off between Skempton's coefficient and stepover width. We validate the numerical model by comparing it to an analytical solution that involves a plane strain shear dislocation on a leaky plane within a linear poroelastic, fluid-saturated solid. This validation demonstrates that a simple analytical solution, primarily dependent on fault dislocation and Skempton's coefficient, has the potential to effectively predict the pore pressure change. The critical jumping width for 50% chance of rupture jumping predicted by our model explains the threshold dimension of the fault step, above which ruptures do not propagate. This study highlights the significance of incorporating poroelastic effects on- and off-fault in understanding the dynamic variations of the effective normal stress, which could significantly alter the overall length of fault rupture.
Carbon dioxide flux of various surface conditions for tundra ecosystem in High Arctic and Antarctic Peninsula
Authors: Chae Namyi , Hwang Hyewon , Choi Taejin , Hong Soon Gyu , Lee Hyoungseok , Lee Bang Yong
Published: March 2024

Carbon dioxide fluxes were measured in the tundra ecosystem in order to evaluate the potential future sensitivity of the carbon cycle to climate change using chamber methods during summer in the Antarctic and high Arctic. The study sites are located on tundra in Baton Peninsula of King George Island, Antarctic Peninsula (62°13’ 28.87"S, 58°47’18.37"W) and high-arctic near Cambridge Bay, Nunavut, Canada (69°7'47.7"N, 105°3'35.3"W). The site of Baton Peninsula is mainly covered with various lichens and mosses and the site of Cambridge Bay is mainly covered with dwarf-shrubs, graminoids, mosses and lichens. CO2 flux was examined to understand change of the carbon cycle over the tundra ecosystems with various conditions for vegetation and soil. The emission CO2 flux and net CO2 exchange showed distinguished differences on type of vegetation and surface soil organic content. The variability of carbon flux depends on soil temperature and soil water content. Net CO2 exchange, soil respiration, and gross primary production were measured or calculated to investigate the influence of the ecosystem in the tundra carbon cycle in the Polar region. This study was supported by a National Research Foundation of Korea grant from the Korean government (MSIP) (NRF-2021M1A5A1065679 and NRF-2021R1I1A1A01053870) and PE 24130.   
Multi-Physics Modeling of Phase Field Fracture in Fluid-Saturated Mining Environments during Excavation.
Authors: Kar Swapnil , Chaudhuri Abhijit
Published: March 2024

This study presents a comprehensive numerical framework for simulating the evolution of fractures in mining sites characterized by fluid-saturated media during excavation. The proposed model integrates phase field fracture mechanics with a coupled solution approach, employing the finite volume method to solve fluid flow equations and the finite element method for geomechanical analysis. The complex interaction between fluid flow and geomechanics is crucial in understanding and predicting fracture propagation in mining environments. The phase field approach allows for a continuous representation of fractures, capturing their initiation, propagation, and coalescence throughout the excavation process. The model incorporates the influence of fluid saturation on fracture behaviour, providing a more realistic representation of the dynamic interplay between the geological medium and the excavated space. The fluid flow equations are discretized using the finite volume method, considering the poroelastic nature of the rock mass. This approach enables the accurate simulation of fluid movement within the saturated medium, considering the changes induced by excavation activities. Simultaneously, the geomechanics equation is solved using the finite element method, accounting for the stress distribution and strain evolution in response to excavation-induced changes. To validate the efficacy of our FEM code, the model is initially subjected to a single fracture scenario, treated as a notch, and benchmarked against published experimental and numerical results for an elastic medium subjected to compressive loads. The successful validation underscores the robustness of our approach in capturing mixed-mode fracturing phenomena in mining environments. The coupling of fluid flow and geomechanics allows for a thorough investigation of the impact of excavation on fracture initiation and propagation in mining environments. The proposed model provides valuable insights into the complex mechanics of fracture evolution in fluid-saturated mining sites, aiding in the development of strategies for optimizing excavation processes and ensuring the safety and stability of mining operations. The integration of finite volume and finite element methods enhances the accuracy and efficiency of the simulation, making the model a powerful tool for researchers and practitioners in the field of mining engineering.
Field monitoring and numerical investigation on the regulation of a large dam structure on the patterns of lateral hyporheic exchange and residence time distributions - The Xinglong Water Conservancy Dam, China
Authors: Li Yiming , Wen Zhang , Schneidewind Uwe , Liu Hui , Krause Stefan
Published: March 2024

Large in-stream structures such as dams can regulate the dynamic of the river stage, which potentially alters the patterns of hyporheic exchange flow (HEF) and mass transfer between the river and adjacent aquifer. However, current studies haven’t focused on how a large dam affects the evolution of HEF and residence time distribution (RTD), especially in the upstream area. In this study, we conducted the geophysical survey and groundwater stage monitoring of three monitoring transects around the XingLong Water Conservancy Dam (XLD) in China, which covers both upstream and downstream riparian areas. Based on these field data, a two-dimensional, horizontal numerical model was built to assess the spatiotemporal evolutions of lateral HEF, hyporheic zone (HZ) and groundwater RTD under the regulation of the XLD. The monitoring and simulation outcomes highlighted the different impact patterns of the XLD in upstream and downstream regions. For instance, the groundwater in the regions upstream of the dam was found to be recharged for the most of time, while the groundwater immediately downstream of the dam was significantly discharged. As the river stage fluctuates, the XLD significantly enhanced the HZ along the upstream river boundary whereas substantial HZ downstream was mainly observed in response to rising or high river stage. Furthermore, the XLD resulted in flow paths around the XLD with short lengths and high flow velocity, which consequently resulted in a significant HZ in the perimeter surrounding the XLD. Results of RTD show that water in the HZ downstream of the XLD was rejuvenated, whereas the HZ upstream of the XLD comprises a mix of aged and rejuvenated waters. These findings emphasized the need for full consideration of river stage dynamics surrounding the dam in analytical or numerical analysis when aiming to assess the bank storage and the aquatic environment in a dam-regulated river corridor aquifer, and have potential implications for the decision of the construction or removal of the dam, river restoration and purification of pollutants in aquifer.
Barley to Ice: Investigating late-winter and spring temperatures in Central Scandinavia for the last 300 years through agro- and cryophenological proxies 
Authors: Skoglund Martin
Published: March 2024

While most past millennium high-resolution temperature reconstructions rely on tree-ring data, there is a notable scarcity of detailed winter-spring temperature records covering the pre-instrumental period in Europe. This gap is evident in central Scandinavia, a region otherwise well covered by tree-ring data. Although tree-ring records in this area have demonstrated a correlation with spring temperatures, the climate signal is dominated by summer temperatures. Achieving a comprehensive understanding of seasonal variations is essential for understanding climate change and variability in the past. This study employs two different sets of sources to reconstruct late-winter and spring temperatures in central Scandinavia since 1697. First, agro-phenological data, covering barley sowing dates in the central agricultural district around lake Storsjön in Jämtland, central Scandinavia, are employed. These sowing dates have been shown to correlate with spring temperatures and cover most of the period since 1699. Second, previously unpublished data are employed in the form of ice-break up dates for Lake Storsjön, extending back to 1697. While each type of data cover most of the study period (1697–2021), combined they present an almost continuous time-series of phenological dates, enabling an attempt at reconstructing late-winter and spring temperatures in central Scandinavia back to 1697.
Piloting and implementation of digital groundwater Information system: A case study of Nepal’s Terai
Authors: Karki Saral , Urfels Anton , Bhuju Pratik
Published: March 2024

Groundwater monitoring and data is key for keeping groundwater use within planetary boundaries. The unmeasured and the unsustainable use of this ‘hidden’ resource poses great sustainability challenges especially impacting low-income countries with poor groundwater governance. However, many groundwater monitoring systems in LMICs do not share data openly and face challenges for financing repair and maintenance of costly telemetric loggers and dashboard systems. This study, therefore, provides an overview and evaluations three different approaches for digital groundwater monitoring and data sharing for informing decision makers on sustainable groundwater management practices. Our work builds on and optimizes the on-going groundwater data collection in Nepal carried out by the Ground Water Resources Development Board – a key partner in this project. Three different digital approaches were experimented from 2020-2021 in the Banke and Bardiya districts of Nepal to recommend a pragmatic and sustainable approach for data collection and management. The three systems included: First, data collection with tablets using ODK based form. Second, digital data collection using a diver with USB data logger. Third, telemetric digital data collection that uploads the data via mobile network and cloud-based storage. Upon completion of the pilot, and careful examination of various costs (operational, maintenance, training), and other carefully identified features the data collection using the ODK based tool was recommended for further scaling and collected data from 2020-present. Furthermore, to complement the data collection using the tablets, the database was designed, and data visualized via an open-source dashboard for efficient data dissemination. The generated data and dashboard has been instrumental in supporting inter-ministerial discussions and interactions to support a transition towards sustainable groundwater management in Nepal.
 
Identifying atmospheric conditions for intermittent, small-scale lightning discharges near the top of thunderstorms
Authors: van Loon Reinaart , Assink Jelle , Scholten Olaf , Hare Brian H , Leijnse Hidde
Published: March 2024

Despite its impact on society, many aspects of lightning, including the initiation and propagation, remain poorly understood. This also applies to a distinct type of intermittent small-scale lightning discharges recorded by the Low-Frequency Array (LOFAR) in the Netherlands (Scholten et al., 2023). The so-called “sparkles” seem uncorrelated and occur relatively high up in thunder clouds near the tropopause. This research investigates the meteorological conditions under which sparkles exist.  

Previous literature suggests a correlation between sparkles and strong updrafts. One hypothesis proposes that powerful updrafts overshooting the level of neutral buoyancy causes a charged screening layer aloft to be entrained into the cloud, resulting in charge pockets. Alternatively, some hypothesize that turbulence plays a vital role in discharge initiation and charge sedimentation. Therefore, intense turbulence near the top of strong updrafts could not only initiate numerous discharges, but could also influence the lightning structures through the spatial charge distribution. 

This project aims to improve the understanding of sparkles by comparing high- resolution LOFAR lighting data with meteorological data. Specifically, thunderstorm dynamics are studied using data from satellites, radar and the HARMONIE weather forecast model. Following the hypotheses, relations are explored between sparkling activity and factors such as updrafts strength, turbulence, mixing, and entrainment of the air aloft.

Scholten, O., Hare, B. M., Dwyer, J., Liu, N., Sterpka, C., Assink, J., ... & Veen, S. T. (2023). Small‐Scale Discharges Observed Near the Top of a Thunderstorm. Geophysical Research Letters, 50(8), e2022GL101304. 
A new spice/heave decomposition of thermohaline variability
Authors: Tailleux Remi
Published: March 2024

The temporal variability of temperature and salinity in the oceans is strongly impacted by the ocean stratification, which tends to constrain lateral advection and mixing to preferentially take place along approximately neutral surfaces. As a result, it is natural to seek a decomposition of thermohaline variability into heave and spice components, which splits temperature and salinity into a component contributing to density and one that is density-compensated. In this talk, I will outline the theoretical foundations for such an approach, based on a recent redefinition of spiciness, and illustrate its usefulness for understanding the variability of the ocean heat and salt contents in the EN4 dataset over the past century.
Episodic events of oblique rifting using InSAR time series and seismicity (2016 – 2023), Reykjanes Peninsula (Iceland) 
Authors: Luo Xingjun , Oestreicher Nicolas , Xu Wenbin , Ruch Joël
Published: March 2024

Oblique rift zones and bookshelf structures in the Reykjanes Peninsula are part of the intricate boundary that separates the North American from the Eurasian plates. Studying their evolution over several years provides a deeper understanding of plate tectonic processes and also aim to better understand the tectonic conditions that precede volcanic eruptions. After a period of dormancy lasting 800 years, the Reykjanes Peninsula has experienced strong episodic plate boundary motions since at least 2017 and four eruptions in 2021, 2022, and 2023 (twice). These events have been accompanied by significant seismic activity and ground displacement related to strain release at the plate boundary and around dike intrusions.Here we employed D-InSAR, stacking-InSAR, and PSI time series to investigate the deformation occurring in the Reykjanes Peninsula from June 2016 to December 2023, covering the period before and during the onset of the eruption phases. Due to the fast deformation during large earthquakes and eruptions, we separately analyze dike intrusions before the four eruptions, five earthquake swarms, and seven time series between the above-mentioned events. The discretization of the observation period allows us to improve the InSAR process for different events and to avoid confusing the deformations originating from different events. Using InSAR and seismicity, we identifiund displacement and earthquake swarms in the Fagradalsfjall area in July 2017, July 2020, August 2020 and October 2020, highlighting an activation of localized portions of the plate boundary at least four years before the first eruption. The overall earthquake distribution aligns with the plate boundary (N070), but suggests a bookshelf structure composed of north-south fault ruptures.We use the vbmethod to decompose the InSAR time-series into independent components of deformation such as intrusions, earthquakes, and tectonic plate motion. From the InSAR time series analysis, we observed that before each dike intrusion, the Southern Fagradalsfjall-Krysuvik () area exhibits an overall southeastward movement. The results of vbICA also suggest that this area has been accelerating since 2020.  The comprehensive observations of tectonic and volcanic activity in the Reykjanes Peninsula, using both InSAR time series and seismicity over seven and a half years provide valuable insights to better understand the onset of oblique rifting events at divergent plate boundaries.
An emerging plume head at Hawaii
Authors: Zhang Lipeng , Cao Zebin , Liu Lijun , Sun Weidong
Published: March 2024

The Hawaii-Emperor seamount chain showed two sub-parallel geographical and geochemical volcanic trends since ~5 Ma, the Loa and Kea trends, regarding which numerous models have been proposed that usually involved a single mantle plume sampling different compositional sources of the deep or shallow mantle. However, the eruption rate of the Hawaiian plume also dramatically increased since ~5 Ma. Moreover, this was accompanied by nearly simultaneous southward bending of the Hawaiian chain. Here, we propose a plume-plume interaction model, where the Kea trend represents the original Hawaiian plume tail, and the Loa trend represents an emerging plume head southeast of the original Hawaiian plume tail with enriched isotopic compositions. Geodynamic modeling suggests that the interaction between the emerging Loa plume head and the existing Hawaiian plume tail is responsible for the southward bending of the Hawaiian chain and the rapid growth of the eruption rate along the hotspot track. We suggest that this double-plume scenario also represents an important mechanism for the formation of other hotspot tracks in the Pacific plate, likely reflecting a dynamic reorganization of the lowermost mantle. It has implications to the formation of the LLSVP and mantle plumes in general.
Regional Flood Risk Assessment Using Ensemble of GCMs
Authors: Kezhkepurath Gangadhara Kiran , Muraleedharan Sarath , Bharath Raja , Kadlec Martin
Published: March 2024

Flood risk assessment is generally carried out at a basin scale by developing hydrologic and hydraulic models with an objective to arrive at hazard/inundation maps for the river segments/reaches. A hydrologic model is used to derive a flood hydrograph corresponding to a specific return period and this is routed through the flood plain of the study area with the aid of a hydraulic model to obtain water surface elevations and inundation extents. This approach is best suited to represent a flood event at a river segment accurately, but the risks associated with floods need to be analyzed on a regional scale for effective flood risk management. As the size of the region increases beyond one basin, this approach fails to realistically represent the flood events across different river segments and basins. The simultaneous occurrences of different return periods on different river segments cannot be captured by this approach. The traditional approach to model these simultaneous occurrences is by using the streamflow records to arrive at spatially correlated stochastic simulations of streamflow. One issue that compounds this problem is the data scarcity in certain regions to accurately estimate the return periods of floods at distinct locations.To address these issues, Impact Forecasting, Aon’s catastrophe model development team, has undertaken a study to simulate stochastic flood events in the Southeast Asian region by considering Malaysia as a case study. The approach involves (i) downscaling of precipitation and temperature data from an ensemble of Global Circulation Models (GCMs), (ii) calibration of a grid-based Rainfall-Runoff (RR) model using available historical data of meteorological variables and streamflow, (iii) providing the downscaled precipitation and temperature data as input to the calibrated RR model to simulate streamflow across the study area and (iv) identifying flood events from the simulated streamflow to extract an exhaustive set of realistic flood events in the region. The approach involves the use of meteorological data of 15,000 years from 7 different GCMs, downscaled to 10 km grids from 100 km resolution. This enables capturing a broader spectrum of potential climate conditions and therefore generating a wide range of possible flood events without relying significantly on in-situ data. The proposed methodology considers the uncertainty inherent in climate models, providing a robust framework for assessing flood risk and results in a more reliable and realistic representation of stochastic flood events over a region. The approach presents a physically based alternative to the commonly used statistical approaches based on extreme value theory and could be a valuable tool for policymakers, researchers, and practitioners in making informed decisions in the face of evolving climate conditions.
Potential forecasting of water accounts of European river basins
Authors: Livina Valerie N.
Published: March 2024

We apply potential forecasting [1,2] to the WISE database that contains water accounts of European river basins [3]. We identify basins under stress and discuss various scenarios of water use. The complexity of water inflows and abstractions introduces sources of uncertainty that require analysis of geophysical, climatic, agricultural and social factors of water use, and this data represents an important case study for development of multivariate data science techniques. We report our findings and projections of hydrological dynamics in European regions.[1] Livina et al, Physica A 2013[2] Billuroglu & Livina, Journal of Failure Analysis and Prevention 2022[3] WISE database, European Environmental Agency, https://www.eea.europa.eu/en/datahub 
Assessing tailings dam long-term failure risk using computer based Landform Evolution Models 
Authors: Hancock Greg , Coulthard tom
Published: March 2024

Tailings are a by-product of the processing of minerals. Tailings can be highly erodible and transportable via fluvial processes and are commonly stored in ‘tailings dams’ which are a feature of many mine sites. These dams and their impounded material will become permanent geomorphic features in the post-mining landscape. The question examined here is - can tailings dams ever be walk-away structures? Tailings dams can fail by both catastrophic and gradual failure. Catastrophic failure occurs when there is a large scale rapid structural failure of the dam wall. Gradual failure occurs over time by slow infilling of the dam and the erosion of the dam wall. This can lead to overtopping of the dam wall and gully incision and failure of the wall and release of sediment to the environment. To understand failure modes and risk profile, computer based Landscape Evolution Models (LEMs) can be used. LEMs have become common tools to quantify risk for mine waste rock dumps and waste repositories.  LEMs provide detailed information on erosion rates, type of erosion and where erosion is likely to occur. They inform long-term behaviour which allows designs to be tested and improved. Here they are used to assess tailings dams where the strengths and weaknesses of different tailings dams designs are examined across a range of climates and material settings. The results show that if well-designed and assuming a well understood climate, a dam can be sufficiently robust to last centuries. However, failure can occur under different climate settings. Modelling also demonstrates that upon failure water quality will be affected for many centuries post-breach if no remedial work is conducted. Longer term, the tailings can be contained if there is maintenance and or an increase in the dam wall height over time or a more robust dam wall constructed to manage extreme events.
Investigation of Atmospheric Correction Methods for InSAR Analysis: A Case Study from Turkiye
Authors: Tekin Ünlütürk Nihal
Published: March 2024

Sentinel-1 satellites conduct satellite passes at various intervals for InSAR analysis to minimize atmospheric effects and investigate different types of deformation. Variables in the atmosphere, particularly factors such as water vapor density, can introduce errors in interferograms. Atmospheric models like GACOS are employed to correct these errors. Applying such models to Sentinel-1 data allows for the correction of atmospheric delays, leading to more precise displacement maps.This study aims to investigate tectonic deformation resulting from the earthquake series in Kahramanmaras, Turkey, on February 6, 2023, using the InSAR method. The primary objective is to mitigate atmospheric effects in InSAR images. In this context, the performance of two tropospheric delay correction methods, namely GACOS and an experimental phase-elevation approach, which largely restrict and address tropospheric noise, has been tested. The standard deviations of both methods have been presented and analyzed. Both methods have been applied to displacement maps, effectively eliminating atmospheric effects from InSAR images and obtaining more accurate and reliable displacement maps.
Unraveling Southern Ocean dynamics: Insights into Antarctic gyre circulation and slope current through direct numerical simulations
Authors: Chidhambaranathan Bajrang , Gayen Bishakhdatta , Vreugdenhil Catherine
Published: March 2024

The Southern Ocean holds a distinctive and pivotal position globally, connecting major ocean basins via its intricate circulation network. This makes it a central hub of oceanic transport. Despite numerous studies, the precise mechanisms governing the local and regional dynamics influencing the rapid poleward heat transport and Antarctic ice melting, aided by the Southern Ocean, remains elusive. Thus, to enhance our comprehension of the role of important regional-scale circulation dynamics like the Weddell, Ross and Kerguelen gyre circulations, high-fidelity direct numerical simulations employing simplified Antarctic geographical features were performed. These simulations were solely forced by the latitudinally varying sea surface temperature. The results obtained were found to closely mirror the real-world system, showcasing phenomena such as the Antarctic circumpolar current, slope current, bottom water formation and polar gyres, even without accounting for the wind forcing. This approach extends solutions from the small turbulence scales to larger planetary processes through down-scaling by employing principles of dynamic similarity, producing energy-conserving flow models. While limited by the absence of salinity and wind forcings, the study demonstrated the viability of direct numerical simulations in comprehending Southern Ocean dynamics, including polar gyres and slope currents. This groundwork lays the foundation for integrating further complexities to fine-tune the system for a more accurate analysis of the Southern Ocean’s physical dynamics - an endeavor of significant importance in a dynamically changing climate landscape.
Rapid development of systematic trend errors in seasonal forecasts and their connection to CMIP6 trend errors
Authors: Beverley Jonathan , Newman Matthew , Hoell Andrew
Published: March 2024

Questions regarding the uncertainty of trends in both historical and projected climate model simulations have been limited by uncertainty about the relative importance of internal variability and external forcing to trends over the relatively short observational record. For example, is the discrepancy between historically simulated tropical Pacific trends (El Niño-like) and observations (broadly, La Niña-like) over recent decades a reflection of sampling issues or model error in internal variability and/or forced global responses (either locally or remotely, such as from the Southern Ocean)? At the same time, it is known that systematic operational seasonal forecast errors (e.g., westward shift of ENSO) are dominated by model errors that develop quite quickly, on the order of a few months of forecast lead time.Here, we suggest that climate model trend errors can be usefully investigated by examining their rapid development within seasonal hindcast datasets. We show that many apparent climate simulation trend discrepancies are evident in trends computed from monthly seasonal hindcasts over the 1994-2016 period for a suite of operational initialised forecast models from C3S and NMME, and in many cases are well developed even at short lead times. These hindcasts use models similar to CMIP-class models and include the same CMIP historical external forcings, but critically are initialised with observations, removing uncertainty related to internal variability. We find these trend errors in many different regions worldwide for several key variables, including sea surface temperature, precipitation and sea level pressure, and investigate their seasonal dependence as well. Notably, we find tropical Pacific "El Niño-like" SST trend errors in all seasons but spring, and related surface pressure, temperature, and precipitation errors in autumn and spring, especially in the North America region. We also find errors in Southern Ocean SSTs, which develop less rapidly than the tropical Pacific SST errors or their global teleconnections.We suggest that these hindcast trend errors reflect sensitivity of the model mean biases to the changing radiative forcing, rather than a forced response. That is, similarity between errors in free running simulations and hindcasts is a result of the seasonal forecast models quickly transitioning from nature’s attractor to the climate model attractor, particularly in the atmospheric model component. This suggests that we might be able to better diagnose the climate model trend errors by looking at the early development of the forecast trend error in the seasonal forecast models.
Energy transition modelling for Arctic off-grid communities
Authors: de Witt Magnus
Published: March 2024

Fossil fuels are the most common energy source for electricity generation among remote Arctic communities. Around 80% of remote Arctic communities are predominantly dependent on fossil fuels. Even if some of the region's raw oil is extracted, the processed diesel must be imported. Transport is complicated and strongly dependent on weather conditions. The harsh Arctic weather conditions make fuel transportation is complex, risky, and costly, leading to an insecure primary energy supply and high fuel prices. For many inhabitants of remote Arctic communities, the high energy costs are a significant cost burden because unemployment, temporary jobs, and a resulting low income are common issues.This presentation will focus on implementation strategies for renewable energy sources into the energy mix or remote Arctic communities, with the aim of lowering the energy cost burden. System dynamics (SD) was used as a methodology to analyze the implementation process. SD is a powerful tool to analyse complex systems with non-linear relationships, as it is expected to find them among the policy strategies for energy transition. Investing in renewable energy technology is a high-risk investment; therefore, the effects of such an investment must be well studied to gain an optimal result. Furthermore, remote communities are often facing financial issues, which limits investments in energy infrastructure. Therefore, the model is looking for affordable ways of investing in energy infrastructure. The model aims for a sustainable performance of the utility provider, whereas the electricity cost for the consumer can be lowered and the utility provider can perform well on a non-profit base.The research indicates that renewables have a significant cost-saving potential. Despite all the positive effects, investment in renewables can be risky and a substantial commitment for small communities. Moreover, depending on the type of renewable energy source, there can be some environmental impact that must be considered as well. With a well-structured integration process, the most can be made out of the investment, which helps lower the energy cost burden even more.
The Parraguirre ice-rock avalanche 1987, semi-arid Andes, Chile -  A holistic revision
Authors: Fürst Johannes J. , Farías-Barahona David , Scaff Lucía , Bruckner Thomas , Mergili Martin
Published: March 2024

On November 29 in 1987, a massive ice-rock avalanche detached near Cerro Rubicano in the Dry Andes east of Santiago de Chile. The avalanche developed into a highly destructive debris flow, which reached a run-out distance of more than 50 km resulting in important damage of infrastructure and causing numerous fatalities. In the wake of the event, several studies have shed light on the event history as well as on the geological, volcano-seismic, meteorological and glacio-hydrological pre-conditioning. Although the El-Niño event, that prevailed in 1987, and the presence of glaciers are considered important factors for the development of such a massive debris flow, a holistic analysis of observational evidence, meteorological conditions and debris-flow simulations remains, to this day, absent.Here, we present new insights obtained from historic aerial photographs and satellite imagery, climate reanalysis, weather stations, hydrographic monitoring and physically-based debris-flow modelling. First, we are able to better constrain the trigger volume and to delineate a first map of the impact area. Second, time records and modelling results affirm the assumed multi-stage character of the event. Third, we postulate that the Parraguirre event can be considered a compound weather event, pre-conditioned by anomalously high temperatures and exceptionally deep snow cover in the days and weeks before the devastating debris flow.