bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fault Structure Reconstruction From Magnetic Anomalies Using an Improved Backtracking Search Optimization Algorithm
Authors: Balkaya Çağlayan , Ekinci Yunus Levent , Ai Hanbing , Biswas Arkoprovo , Göktürkler Gökhan 
Published: May 2024

AbstractFault structure reconstruction is an important aspect of magnetic prospecting as it contributes to understanding tectonic history, hazard assessment, and infrastructure planning. Metaheuristics have proven useful in estimating fault structure parameters from geophysical anomalies. Recently, a modified version of the Backtracking Search Optimization Algorithm (BSA), named mBSA, has been proposed that combines mutation steps of BSA and Differential Evolution (DE) algorithms to achieve a better balance between exploration and exploitation. Here, we present imBSA as an efficient approach that builds on the improvements of mBSA. It uses an adaptive amplitude control factor in the mutation step derived from a normally distributed random number obtained via an exponential function. The performances of these approaches were tested on some widely used benchmark functions such as Rosenbrock, Rastrigin, Griewank, and Himmelblau. Synthetic magnetic fault anomalies were evaluated with and without noise, as well as three real anomalies from the Dehri (India), Perth Basin, and Lachlan Fold Belt (Australia). Prior to the optimizations, the solvability of the model parameters was examined using some error topography images. The obtained solutions in the synthetic cases were evaluated using principal component analysis. In addition, a novel visualization option for high‐dimensional optimization problems was introduced. The experiments showed that imBSA has a faster convergence rate and better optimization statistics compared to BSA and mBSA. Therefore, it is believed to be an efficient and good alternative tool to widely used metaheuristics such as Particle Swarm Optimization and DE in explaining geophysical anomalies and optimization problems in other geoscientific disciplines.
Future Climate Change Impacts on Rice in Uttar Pradesh, India's Most Populous Agrarian State
Authors: Singh Jyoti , Sahany Sandeep , Singh K. K. , Robock Alan , Xia Lili 
Published: May 2024

AbstractUttar Pradesh, with a population of 237 million, is the largest agrarian state in India, located in the Indo‐Gangetic plains. Rice cultivation is widespread across all districts of Uttar Pradesh, which have varying climate regimes, irrigation infrastructures, crop management practices, and farm sizes. The state is characterized by different agroecological zones (AEZs) with semi‐arid to sub‐humid climates with significant variability in monsoon rainfall. In this study, the impact of climate change on Kharif‐season rice is estimated using crop‐climate scenarios in Uttar Pradesh. A process‐based Crop Simulation Model, Crop Estimation through Resource and Environment Synthesis‐Rice, was simulated with bias‐corrected and downscaled climate data for historical (1995–2014) and three future periods (the 2030s, 2050s, and 2090s) for two mitigation pathways (SSP2‐4.5 and SSP5‐8.5) from the Coupled Model Intercomparison Project 6. Phenology, irrigation amount, crop evapotranspiration, yield, and water use efficiency were evaluated and assessed for all AEZs. Based on the ensemble of 16 climate models, rainfed rice yield increased in the AEZs of western Uttar Pradesh due to increased rainfall, while in eastern Uttar Pradesh yield decreased, under both shared socioeconomic pathways (SSPs). Irrigated rice yield decreased in all AEZs under both SSPs due to an increase in temperature and a decrease in the length of the growing period, with reductions of up to 20% by the 2090s. Irrigation requirements decreased from the 2030s to the 2090s due to increased rainfall and decreased crop evapotranspiration. Despite the projected increase in rainfed yield, the overall rice yield is expected to decrease in the future under both SSPs.
A Framework for Multisector Scenarios of Outcomes for Well‐Being and Resilience
Authors: O’Neill Brian C. , Morris Jennifer , Lamontagne Jonathan , Weyant John , Wise Marshall 
Published: May 2024

AbstractShared community scenarios of societal and environmental system changes have underpinned a broad range of research and assessment studies over the past several decades. These scenarios have largely aimed to address specific questions within broad issue areas like climate change or biodiversity and generally provided information on the drivers of change. The consequences of those drivers, such as impacts on society and policy responses, have tended to be left to the research community to investigate, using scenarios of drivers as inputs to their studies, producing projections of a disparate set of relevant output metrics. While this approach has had many benefits, it has fallen short of producing a robust, comparable literature describing outcomes across studies in common metrics. We argue that new scenarios are needed that extend current approaches to be organized around common outcome metrics for the well‐being and resilience of society and ecosystems. We propose an approach that would focus on agreed upon outcomes for well‐being and resilience as well as critical drivers of change, cut across issues and scales in multiple sectors, and draw on new systematic methods of scenario generation and discovery to highlight scenarios that are most critical in understanding societal risks and responding to them. Research derived from this outcome‐based scenario development approach would facilitate improved assessment of risks of and responses to a range of stressors and the multi‐sector interactions they generate.
Linking Dissolved Organic Matter Composition to Landscape Properties in Wetlands Across the United States of America
Authors: Kurek Martin R. , Wickland Kimberly P. , Nichols Natalie A. , McKenna Amy M. , Anderson Steven M. , Dornblaser Mark M. , Koupaei‐Abyazani Nikaan , Poulin Brett A. , Bansal Sheel , Fellman Jason B. , Druschel Gregory K. , Bernhardt Emily S. , Spencer Robert G. M. 
Published: May 2024

AbstractWetlands are integral to the global carbon cycle, serving as both a source and a sink for organic carbon. Their potential for carbon storage will likely change in the coming decades in response to higher temperatures and variable precipitation patterns. We characterized the dissolved organic carbon (DOC) and dissolved organic matter (DOM) composition from 12 different wetland sites across the USA spanning gradients in climate, landcover, sampling depth, and hydroperiod for comparison to DOM in other inland waters. Using absorption spectroscopy, parallel factor analysis modeling, and ultra‐high resolution mass spectroscopy, we identified differences in DOM sourcing and processing by geographic site. Wetland DOM composition was driven primarily by differences in landcover where forested sites contained greater aromatic and oxygenated DOM content compared to grassland/herbaceous sites which were more aliphatic and enriched in N and S molecular formulae. Furthermore, surface and porewater DOM was also influenced by properties such as soil type, organic matter content, and precipitation. Surface water DOM was relatively enriched in oxygenated higher molecular weight formulae representing HUPHigh O/C compounds than porewaters, whose DOM composition suggests abiotic sulfurization from dissolved inorganic sulfide. Finally, we identified a group of persistent molecular formulae (3,489) present across all sites and sampling depths (i.e., the signature of wetland DOM) that are likely important for riverine‐to‐coastal DOM transport. As anthropogenic disturbances continue to impact temperate wetlands, this study highlights drivers of DOM composition fundamental for understanding how wetland organic carbon will change, and thus its role in biogeochemical cycling.
Effect of Water‐Rock Ratio on the Stable Isotope Record of Fluid‐Rock‐Deformation Interactions in Detachment Shear Zone
Authors: Gottardi Raphaël , Mire Camron , Davis Niya , Casale Gabriele 
Published: May 2024

AbstractOxygen and hydrogen stable isotope analyses of quartz and muscovite veins from the footwall of the Raft River detachment shear zone (Utah) provide insight into the hydrology and fluid‐rock interactions during ductile deformation. Samples were collected from veins containing 90%–100% quartz with orientations either at a high angle or sub‐parallel to the surrounding quartzite mylonite foliation. Stable isotope analysis was performed on 10 samples and compared with previous quartzite mylonite isotope data sets. The results indicate that the fluid present during deformation of the shear zone was meteoric in origin, with a δ2H value of approximately −100‰ and a δ18O value of approximately −13.7‰. Oxygen stable isotope O18O depletion correlates with the muscovite content of the analyzed rocks. Many of the analyzed samples in this and other studies show an apparent lack of equilibrium between the oxygen and hydrogen isotope systems, which can be explained by hydrogen and oxygen isotope exchange at varying fluid‐rock ratios. Our results suggest that the Raft River detachment shear zone had a low static fluid‐rock ratio (<0.1), yet experienced episodic influxes of fluids through semi‐brittle structures. This fluid was then expelled out into the surrounding mylonite following progressive shearing, causing further 18O‐depletion and fluid‐related embrittlement.
Isotopic Evidence for Degradation of Particulate Black Carbon in the Ocean
Authors: Sarkar Siddhartha , Rahman Abdur , Khan Mohammad Atif , Rathi Ajayeta , Ragavan P. , Singh Arvind , Kumar Sanjeev 
Published: May 2024

AbstractBlack carbon (BC) has emerged as an integral part of the global carbon (C) cycle, constituting 12% ± 5% of the organic C pool in rivers and soils, with the potential to generate negative climate feedback. However, its ability to sequester C depends on the recalcitrant nature of BC in the environment, which is under debate. Using CTO‐375 method and by measuring concentrations and isotopic compositions of particulate BC (δ13CPBC), we explore the transformation of particulate black carbon (PBC) along the atmosphere‐river‐ocean continuum. Significantly high δ13CPBC in the ocean compared to rivers and atmospheric particulate matter indicates (a) degradation of PBC, potentially through photodegradation and leaching, and/or (b) availability of an enriched source other than fluvial or aeolian inputs. This evidence for degradation of PBC in aquatic systems warrants rethinking on its C sequestration potential and role in aquatic C biogeochemistry and further raises concerns regarding the use of sedimentary BC as a paleoenvironmental proxy.
Understanding the Cascade: Removing GCM Biases Improves Dynamically Downscaled Climate Projections
Authors: Rahimi Stefan , Huang Lei , Norris Jesse , Hall Alex , Goldenson Naomi , Risser Mark , Feldman Daniel R. , Lebo Zachary J. , Dennis Eli , Thackeray Chad 
Published: May 2024

AbstractPolarization surrounding bias correction (BC) in creating climate projections arises from its lack of physicality. Here, we perform and analyze 18 dynamical downscaling simulations (with and without BC) to better understand the physical impacts of BC, applied before downscaling, on regional climate output across the western United States. Without BC, downscaled precipitation is systematically and unrealistically wet biased compared to a hierarchy of observationally based datasets over the 1980–2014 period due to cascading mean‐state Global Climate Model (GCM) biases: (a) overly strong lower‐tropospheric lapse rates (5 K/km), (b) overly cold (2 K) tropospheric temperatures, and (c) anomalous mid‐tropospheric cyclonic vorticity advection. With BC, downscaled precipitation (snow) biases are virtually eliminated (halved). Identified GCM biases are common to the broader Coupled Model Intercomparison Project ensemble. Physical effects of BC on the quality of the regionalized projections, pending an evaluation of BC's distortion of the downscaled climate response, may motivate its broader application by dynamical downscalers.
BARREL Observations of Microburst Events With a Slowly‐Varying Component
Authors: Cantwell Kelly , Millan Robyn 
Published: May 2024

AbstractElectron microburst precipitation has been shown to have significant potential for depletion of the outer radiation belt. We present observations from the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) of six (five unique and one dual‐balloon observation) microburst events, each containing minutes to hours of persistent microbursts. We find that each event included a slowly‐varying smooth precipitation component underlying the bursty component. The smooth component has not yet been fully characterized in the literature; we have written a program to identify microburst events and quantify the relative contributions of each component in the BARREL data. In all six events analyzed, the smooth component contributed more to the total X‐ray counts measured, indicating that the smooth component could contribute significantly to radiation belt loss.
Evidence for and Against Temperate Ice in Antarctic Shear Margins From Radar‐Depth Sounding Data
Authors: Summers P. T. , Schroeder D. M. , May D. F. , Suckale J. 
Published: May 2024

AbstractThe majority of ice mass loss from Antarctica flows through narrow, fast sliding regions of ice. The lateral boundaries of these regions, termed shear margins, are characterized by lateral shear strains in excess of ∼10−3 yr−1. Shear heating within these margins could warm ice significantly–even to the melting point–but other processes such as lateral advection of cold ice and fabric development compete with this effect. Radar observations can help constrain where temperate ice exists because englacial temperature increases electric conductivity which increases radar attenuation. We utilize the temperature‐dependent attenuation of ice to develop a novel method for constraining englacial temperature in shear margins by combining existing thermal models with very high frequency radar depth‐sounding data. We find evidence supporting temperate shear margins in 18 locations and find evidence for non‐temperate margins in 37 locations, notably in the Amundsen Sea Embayment.
Io's Long‐Wavelength Topography as a Probe for a Subsurface Magma Ocean
Authors: Gyalay S. , Nimmo F. 
Published: May 2024

AbstractWe investigated how spatial variations in tidal heating affect Io's isostatic topography at long wavelengths. The long‐wavelength relief is less than the 0.3 km uncertainty in Io's global shape. Assuming Airy isostasy, degree‐2 topography <0.3 km amplitude is only possible if surface heat flux varies spatially by <19% of the mean value. This is consistent with Io's volcano distribution and is possible if tidal heat is generated within and redistributed by a convecting layer underneath the lithosphere. However, that layer would require a viscosity <1010 Pa s. A magma ocean would have low enough viscosity but would not generate enough tidal heat internally. Conversely, assuming Pratt isostasy, we found ∼0.15 km degree‐2 topography is easily achievable. If a magma ocean was present, Airy isostasy would dominate; we therefore conclude that Io is unlikely to possess a magma ocean.
Electron Precipitation Driven by EMIC Waves: Two Types of Energy Dispersion
Authors: Grach Veronika S. , Artemyev Anton V. , Demekhov Andrei G. , Zhang Xiao‐Jia , Bortnik Jacob , Angelopoulos Vassilis 
Published: May 2024

AbstractElectromagnetic ion cyclotron (EMIC) waves can very rapidly and effectively scatter relativistic electrons into the atmosphere. EMIC‐driven precipitation bursts can be detected by low‐altitude spacecraft, and analysis of the fine structure of such bursts may reveal unique information about the near‐equatorial EMIC source region. In this study, we report, for the first time, observations of EMIC‐driven electron precipitation exhibiting energy, E, dispersion as a function of latitude (and hence L‐shell): two predominant categories exhibit dE/dL > 0 and dE/dL < 0. We interpret precipitation with dE/dL < 0 as due to the typical inward radial gradient of cold plasma density and equatorial magnetic field (∼65% of the statistics). Precipitation with dE/dL > 0 is interpreted as due to an outward radial gradient of the equatorial magnetic field, likely produced by energetic ions freshly injected into the ring current (∼35% of the statistics). The observed energy dispersion of EMIC‐driven electron precipitation was reproduced in simulations.
Sea Ice‐Driven Iceberg Drift in Baffin Bay
Authors: Marson J. M. , Myers P. G. , Garbo A. , Copland L. , Mueller D. 
Published: May 2024

AbstractBaffin Bay is the travel destination of most icebergs calving from west Greenland. They commonly follow the bay's cyclonic circulation and might end up far south along the coast of Newfoundland and Labrador, where many shipping routes converge. Given the hazard that icebergs pose to marine transportation, understanding their distribution is fundamental. One of the forces driving iceberg drift arises from the presence of sea ice. Observations in the Southern Ocean indicate that icebergs get locked in thick and concentrated sea ice. We present observations that support the occurrence of this sea ice locking mechanism (SIL) in Baffin Bay as well. Most iceberg models, however, represent the sea ice force over an iceberg as a simple drag force. Here, we implement a new parameterization in the iceberg module of the Nucleus for European Modeling of the Ocean (NEMO‐ICB) to represent SIL. We show that, by using this new parameterization, icebergs are more likely to travel outside of the Baffin Island Current during winter, which is supported by satellite observations. There is a slight improvement in the representation of iceberg severity along the coast of Newfoundland and Labrador and a slight shift of iceberg melt toward this region and Lancaster Sound/Hudson Strait. Although the impacts of icebergs on sea ice are still not represented, and targeted observations are needed for model calibration regarding sea ice concentration thresholds from which icebergs get locked, we are confident that this model improvement takes iceberg modeling one step forward toward reality.
Underway pCO2 Surveys Unravel CO2 Invasion of Lake Superior From Seasonal Variability
Authors: Sandborn D. E. , Minor E. C. 
Published: May 2024

AbstractThis study observed seasonal trends and inferred drivers of CO2 biogeochemistry at the air‐water interface of Lake Superior. Underway carbon dioxide partial pressure (pCO2) was measured in surface water during 69 transects spanning ice free seasons of 2019‐2022. These data comprise the first multiannual pCO2 time series in the Laurentian Great Lakes. Surface water pCO2 was closely tied to increasing atmospheric pCO2 over a 100‐day CO2 equilibration timescale, while seasonal variability was controlled equally by thermal and non‐thermal drivers during the ice‐free season. Comparison to previous modeling efforts indicated that Lake Superior surface pCO2 increased with two decades of rising atmospheric CO2. Spatial heterogeneity in CO2 dynamics was highlighted by a conductivity‐based delineation of “riverine” and “pelagic” regimes, each of which was associated with net CO2 influx over Julian days 100–300 on the order of 25 Gmol C. These findings refine previous estimates of Lake Superior C fluxes, support predictions of anthropogenic CO2 invasion during the ice‐free season, point to new observation strategies for large lakes, and highlight an urgent need for studies of changes to lacustrine C cycling.
On the Divergent Evolution of ENSO After the Coastal El Niños in 2017 and 2023
Authors: Tan Wei , Hu Zeng‐Zhen , McPhaden Michael J. , Zhu Congwen , Li Xiaofan , Liu Yunyun 
Published: May 2024

AbstractCoastal El Niño is an extreme situation of El Niño‐Southern Oscillation (ENSO) with sea surface temperature warming confined in the far‐eastern equatorial Pacific. Some coastal El Niños evolve into a basin scale El Niño, and some don't, implying a diversity in ENSO evolutions after a coastal El Niño event. In this study, the coastal El Niños in 2017 and 2023 are selected to examine their subsequent evolution. Both coastal El Niños developed after a La Niña, with the former followed by a La Niña and the latter by a basin‐scale El Niño. The cold (warm) subsurface temperatures in 2017 (2023) were key factors leading to the divergent ENSO evolution. Convection over the western tropical Pacific and the atmospheric circulation anomalies across the equatorial Pacific also contributed to the differences. Model predictions suggest that differences in ENSO evolution after a coastal El Niño are associated with differences in ENSO predictability.
Forest Disturbance Thresholds and Cumulative Hydrological Impacts
Authors: Hou Yiping , Wei Xiaohua 
Published: May 2024

AbstractForest disturbance threshold is defined as a critical disturbance level (e.g., % of forest cover change) in forested landscapes above which significant hydrological impacts are detected. Determining disturbance thresholds is critically important for supporting forest management to ensure the sustaining of ecological and hydrological functions. However, there are very few quantitative evaluations of forest disturbance thresholds globally. In this study, we applied a well‐tested methodology (the modified double mass curve) to derive the long‐term, continuous hydrological response curves and then to quantify forest disturbance thresholds on annual streamflow in 42 forested watersheds in British Columbia, Canada. The results show that forest disturbance thresholds for significant and cumulative hydrological impacts vary from 7% to 52% of cumulative equivalent clear‐cut area with an average of 17% or from 8% to 52% of disturbed area with an average of 19%. Climate (inter‐annual and intra‐annual) and watershed properties exert critical controls on forest disturbance thresholds. Watersheds with greater snowfall proportions (more annual precipitation falling as snow), more desynchronizations (temporal mismatching) of energy demand and water supply at the intra‐annual scale, less diverse ecosystems, and larger watershed sizes have lower forest disturbance thresholds. Given the present forest disturbance levels in the central interior of British Columbia, about half (53%) of the forested watersheds have already crossed the average disturbance threshold. These results highlight that watershed planning and management using forest disturbance thresholds must carefully consider local climate and watershed properties. The methodology can be effectively and robustly extended elsewhere around the globe.