bluuebunny/crossref_metadata_2025 huggingface dataset:
Enabling curiosity-driven science and digital twins for earthquake physics in the exascale era
Authors: Gabriel Alice-Agnes
Published: March 2024

Geohazards and risks increase worldwide rapidly due to continuing urbanization, climate change, and high-risk critical distributed infrastructure. The longest modern instrumental records of earthquakes cover less than 100 years, while recurrence intervals of large earthquakes are hundreds of years or more. Increasingly dense observations and physics-based simulations empowered by supercomputing provide pathways for overcoming the lack of data and elucidating spatiotemporal patterns that extend our knowledge beyond sporadic case studies and average statistical laws - however, are typically challenging to integrate.Digital Twins are emerging in Solid Earth Science, allowing curiosity-driven science to test scientific hypotheses against observations over ranges of space-time scales not accessible for laboratory and field observations. The results can clarify processes leading to large earthquakes, improve our forecasting ability, and enhance the general understanding of earthquakes and faults.In this presentation, I will highlight Geo-INQUIRE (www.geo-inquire.eu), DT-Geo (www.dt-geo.eu) and ChEESE-2P (www.cheese2.eu), European projects that aim to overcome cross-domain barriers and will exploit innovative data management techniques, modeling and simulation methods, developments in AI and big data, and extend existing data infrastructures to disseminate these resources to the wider scientific community. Specifically, we will provide and enhance access to selected key data, products, and services, enabling the dynamic processes within the geosphere to be monitored and modeled at new levels of spatial and temporal detail and precision.
Ferromagnetism as a pressure proxy for metamorphism?
Authors: Ou Qiqi , Mitchell Ross
Published: March 2024

Throughout geological history, changes in metamorphic conditions plays a crucial role in reflecting the evolution of the tectono-thermal conditions of Earth. The determination of temperature and pressure conditions for evaluating metamorphism typically relies on a limited number of samples, and the testing and analysis process requires significant time and work for thin section preparation, thin section analysis, geochemical analysis, as well as pseudosection calculations based on thin section and geochemical constraints. Following these procedures, it is commonly assumed that localized results can represent thermobaric conditions at regional or even orogenic belt scales. This assumption holds true when metamorphism reflects rock burial depth (i.e., lithostatic pressure). However, on small spatial scales, deviational stresses resulting from tectonic extension or compression can induce structural underpressure or overpressure, thereby rendering this assumption invalid. Therefore, we introduce magnetic susceptibility (k) as a measure of material magnetization in an applied magnetic field. It exhibits two key characteristics: (i) Fe-Ti oxides in mafic rocks display a mineral phase sequence largely associated with changes in pressure, with approximate pressure ranges for ilmenite + magnetite (<6 kbar), ilmenite (6–12 kbar), rutile + ilmenite (~12 kbar), and rutile (>12 kbar); (ii) Magnetic susceptibility can be quickly and extensively measured to reflect variations in Fe-Ti oxide content within mafic rocks. Our findings demonstrate that Fe content decreases while Ti content increases with increasing pressure. Thus, as pressure increases during prograde metamorphism, Ti generally replaces Fe, and this process can be detected as systematic decreases in magnetic susceptibility. This pressure–susceptibility correlation is further corroborated by retrograde metamorphism, where k inversely increases with decreasing pressure during exhumation. Based on our comprehensive petrological and geophysical analysis of mafic rock samples collected from the Paleoproterozoic (ca. 1.8 Ga) Jiao–Liao–Ji Belt of the North China craton, including coupled thin section, geochemical, and thermal susceptibility (kT) fingerprinting of Fe-Ti oxides, we posit that magnetic susceptibility can serve as a reliable indicator for discerning metamorphic pressure. Furthermore, owing to its ease of rapid and extensive data acquisition in fieldwork settings, we contend that it can play a pivotal role in identifying potential deviations from lithostatic stress due to tectonic stress on either small and/or large spatial scales.
Intraplate Volcanism by Spontaneous Shallow Upper Mantle Melt Focusing
Authors: Song Jung-Hun , Kim Seongryong , Rhie Junkee , Kang Tae-Seob
Published: March 2024

Intraplate volcanism signifies persistent magmatic activity within plate interiors far from active plate boundaries. However, due to limited assessment of the detailed physical conditions of the intraplate upper mantle, the fundamental mechanism behind the genesis of mantle magma remains poorly understood. We analyzed the temperature conditions of the upper mantle beneath global intraplate volcanic regions estimated from seismic velocity and geochemical data. We revealed that excluding volcanoes near major plumes, large proportions (> 70%) of the volcanoes are situated above the upper mantle with moderate temperatures comparable to or colder than those found at mid-oceanic ridges (potential temperature (Tp) ~1250–1350°C). These volcanoes also overlie regions of low vertical and horizontal asthenospheric shear estimated by global mantle convection simulations. Without peculiarities in thermal and large-scale mantle dynamics, we inferred that these volcanic activities are likely driven by a small-scale local convective process confined to the shallow upper mantle. To constrain a more detailed process of intraplate volcanism, we focus on analyzing the upper mantle rheology and melt distribution beneath intraplate volcanoes in NE Asia. Thermodynamic properties, conservatively constrained by high-frequency seismic attenuation and velocities, revealed the common presence of low-viscosity zones concentrated beneath the volcanoes at shallow asthenospheric depths (< 200 km). These regions contain a small fraction of melt (~0.05–0.8%) at cold-to-moderate temperatures (Tp ~1300–1350°C) compared to the average mantle aligning with global analyses. A series of evidence potentially suggests the existence of localized mantle upflux focused beneath intraplate volcanoes. Considering the amount and extent of the estimated mantle melts and numerical mantle convection simulations with lithospheric structures, we propose that undulations in the lithosphere and asthenosphere boundary could play a primary role in controlling the small-scale mantle convection and the location of intraplate mantle melting. Our estimation supports the possibility of the ubiquitous occurrence of intraplate volcanoes independent of dynamic forces for deriving active mantle upwellings (e.g., thermal or chemical buoyancy).
Organic carbon health burden in the Indo-Gangetic Plain: Exposures, risks, and mitigation
Authors: a. Vidya , Dubey Kanishtha , Verma Shubha
Published: March 2024

Organic carbon (OC) aerosols are complex carbon-containing particles suspended in the atmosphere. OC accounts for a large fraction of atmospheric aerosol and significantly affects air quality, atmospheric chemistry, human health, and climate forcing. This study focuses on assessing the specific influence of OC aerosols on public health within the Indo-Gangetic Plain (IGP). The assessment was done with an efficiently modeled OC distribution in a fine-resolved chemistry-transport model, CHIMERE, using the Weather Research and Forecasting (WRF) model as the meteorological driver in the offline mode. Simulations are carried out at a horizontal resolution of 0.1◦×0.1◦ over the IGP domain (20oN to 30.9oN and 75oE to 89.3oE). The health assessment was done for the seasonal mean of winter (January, February, November and December) OC concentration.Higher OC concentrations were consistently observed across diverse area types in the IGP: Megacity (Kolkata and Delhi), Urban (Agra, Varanasi, Kanpur), and Semiurban (Kharagpur). Wintertime OC concentrations were significantly higher than the established Theoretical Threshold Limit (TTL) of 16 μg m-3. OC all-day (daytime) concentrations exceeded 60 (30) μg m-3, which is about 4 (2) times the TTL, in urban and megacity areas. Over 95% of the populations in semi-urban, urban, and megacity areas are exposed to OC concentrations above the threshold, with rural and semi-rural populations also experiencing substantial exposure. Relative risk (RR) and Cardiovascular Mortality (CVM) associated with OC exposure during the winter months were assessed to evaluate the health impacts. RR values consistently exceed one across the IGP, indicating potential health risks associated with wintertime OC exposure. The burden of CVM attributable to OC is estimated to encompass approximately 2,00,000 annual deaths across the entire IGP. The CVM attributable to OC in comparison to both PM2.5 and BC was found to be about 1.5 times higher over Agra and Kanpur. This underscores the need for immediate policy interventions to address elevated OC concentrations in the IGP, especially in high-risk areas like Agra and Kanpur, mitigating the significant burden of CVM associated with wintertime OC exposure.  
Progress and perspectives on using the Lattice Boltzmann Method for geodynamics simulation research
Authors: Mora Peter , Morra Gabriele , Honarbakhsh Leila , Huttig Christian , Tosi Nicola
Published: March 2024

The Thermal Lattice Boltzmann Method (TLBM) for geodynamical simulation research offers an alternative to classical PDE based methods for 2D and 3D geodynamics simulation research. It is based on modelling the Boltzmann equation on a discrete lattice which involves the movement of number densities carrying mass and energy density on a discrete lattice and their relaxation to equilibrium which model collisions. We present examples in 2D and 3D to illustrate the capabilities, performance, and accuracy of this method for geodynamics research, namely: (1) ability to handle highly nonlinear rheology, ultra-high Rayleigh numbers, a wide range of Prandtl numbers, and multiphase flow, (2) linear scaling up to 300K cores on HPC CPU clusters, and (3) ability to closely match the Blankenbach benchmarks demonstrating the LBMs accuracy. Examples in 2D include high Rayleigh number simulations to Ra = 1015, highly nonlinear rheology leading to the emergence of plate-tectonic like behaviour, and planetary accretion. Examples in 3D include modelling of a mantle with an aspect ratio of 25x25x1 representing a case from a recent nature paper, and modelling a case of an aspect ratio of 14.4x14.4x1 which is similar that of the Earth for Ra = 106 and Pr = 100. Potential benefits of the TLBM include an ability for higher resolution simulations than can be achieved using classical methods, and faster simulations which may allow phase space studies to determine which parameter combinations lead to which class of behaviour. As the TLBM is a new method for geodynamical simulation, it will take some time to determine the limits of this method. For example, a simulation can be made to run faster by increasing the physical time step, but eventually, if the time step is too large, the Mach numbers on the lattice become too high leading to lower accuracy and eventually instability due to non-convergence of the collision step which involves a relaxation of the number densities to equilibrium. We believe that over time, these limitations will become well understood and that the outstanding parallel scaling performance on HPC CPU clusters of the TLBM - which makes possible 3D models up to 50003 - will  open up exascale computing to geodynamics research and will lead to fundamental advances in geodynamics research. As such, the TLBM may become a valuable tool to advance geodynamics research into the future through large to exascale simulations that may lead to new insights into the dynamics and evolution of the earth and exoplanets from the early lava world stage through to plate tectonics or other regimes.
A Study on the analysis of groundwater flow using thermal and hydrochemical data of groundwater and surface water in the karst area of Samcheok, Korea
Authors: Ryu Han-Sun , Kim Heejung
Published: March 2024

In this study, a study on groundwater flow analysis was conducted using hydrochemical and thermal data to find out the flow of groundwater and pollutant behavior in the karst area and to secure countermeasures for problems related to water quality and water resource stability. The flow characteristics were identified using the study area's overall topographic slope and groundwater map. It is more vulnerable to groundwater pollution because it belongs to the discharge stand where groundwater from the west is discharged into the sea. The vertical hydraulic gradient was measured to confirm the direction of recharge and discharge of groundwater and surface water, and it can be seen that the inflow and outflow of groundwater-surface water is active. In both Gyogokcheon (Gyogok-ri) and Sohancheon (Hamaengbang-ri), the recharge of groundwater tends to be more dominant, and in the case of Sohancheon located in Hamangbang-ri, the recharge of groundwater in summer and winter was more active than in spring and fall. In addition, the residence time of groundwater and the recharge and mixing of surface water according to the flow of groundwater and the behavior of pollutants were analyzed using hydrochemical data. There was a distinct difference in radon concentration values between Gyogokcheon (gneiss-based rock) and Sohancheon (limestone-based rock). In the case of Hamaengbang-ri, radon concentration values were not significantly divided according to surface water, groundwater-surface water mixing section (hyporheic zone), and cave water. In the case of Gyogok-ri, radon concentration was used as one of the indicators to estimate the mixing ratio of groundwater and surface water in the hyporheic zone. This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (grant numbers 2019R1I1A2A01057002 and 2019R1A6A1A03033167). This subject is supported by Korea Ministry of Environment as "The SS(Surface Soil conservation and management) projects; 2019002820004.
How does Iya Volcano threaten coastal population in Sawu Sea, Indonesia?
Authors: Saaduddin Saaduddin , Sakka Sakka , Amiruddin Amiruddin , Alimuddin Hamzah Muhammad
Published: March 2024

To assess the potential threats posed by possible landslide-induced tsunamis in Sawu Sea, triggered by Iya volcano's activity, a thorough investigation should be carried out. This active volcano is situated in the southernmost part of Ende, East Nusa Tenggara Province in Indonesia. This volcano faces three densely populated islands: Ende, Timur, and Sumba. The mechanism formed the crater in south part of the edifice is still unknown, but the great explosion in 1969 has the potential answer. The explosion released tons of material and possibly triggered the instability on the edifice and generate tsunamis in Sawu sea. The tsunami generation will be modelled using the finite element method, which will solve the Navier-Stokes equation for incompressible flows in a multi-material simulation. A tool which is so-called Fluidity will be used in this project. The expected results of this study include the physical characteristics of the tsunami, such as the potential run-out distance, run-up height, and arrival time on nearby islands. Moreover, the study will include an exposure analysis to aid authorized institutions and local governments in risk mitigation.
How do the Red Sea and Gulf of Aden rifts connect? 
Authors: Muluneh Ameha , Brune Sascha , Pagli Carolina , La Rosa Alessandro , Keir Derek , Neuharth Derek , Corti Giacomo
Published: March 2024

The Afar rift in East Africa is a classic natural laboratory where we can directly observe tectonic processes related to the ongoing deformation between the Red Sea and Gulf of Aden rifts. While there have been several geophysical studies conducted in the region, we know surprisingly little about the mechanism of connection between the two rifts. Earlier studies suggest that the two rifts form an overlap zone within which crustal blocks rotate in a clockwise sense via rift parallel strike slip faults. In contrast, geodetic data indicate a direct linkage via a zone of extension with dextral shearing at the lateral tips of the zone of extension and minimal vertical axis block rotation. Here we combine high-resolution 3D lithospheric scale geodynamic models using ASPECT and strain rate derived from geodesy to fully capture the evolution of deformation between the Red Sea and Gulf of Aden rifts as they evolve. Our results demonstrate that the two rifts link via a transtensional deformation zone, where incipient transform faulting, overlapping en-echelon basins and vertical axis block rotation play roles at different stages of the evolution. We argue that the discrepancy between the proposed models for the Red Sea and Gulf of Aden rift connection can be reconciled when considering the spatial and temporal evolution of the rifts.
A glimpse into the Hydroclimate and environmental trends of the past two millennia in Southern Transylvania, Romania
Authors: Ruskal Agnes , Grindean Roxana , Diaconu Andrei-Cosmin , Tanțău Ioan
Published: March 2024

Considering the importance of hydroclimate conditions in the development of both natural and anthropic environments, a better understanding of past conditions is imperative. Keeping this as a main trajectory, the objective of our study is the reconstruction of the past hydroclimate and environmental conditions in Central Romania over the last two millennia, by a high-resolution analysis of a peat sequence from Arpaşu de Sus (Făgăraș Depression, Southern Transylvania). We used biotic proxies (testate amoebae, pollen and spores) to quantitatively reconstruct the water level depth fluctuations in the peat bog and abiotic (lithology, AMS radiocarbon dating, organic matter content, bulk density, magnetic susceptibility) to reconstruct the vegetation dynamics and the human impact in the studied area.The peat bog had ombrotrophic characteristics throughout the studied period, with organic matter percentages ranging from 85 to 95%. The pollen analysis results show that the vegetation of this interval was characterized by extensive forests dominated by Fagus sylvatica, accompanied by Carpinus betulus and Alnus sp. The reconstructed water table depth values, based on testate amoeba assemblages, fluctuated between 32.9 and 11.8 cm.Our findings are in good agreement with other results from Romania and Central-Eastern Europe, bringing valuable insight to a better understanding of the hydroclimate changes that occurred in Europe in the last two millennia.
Significant contribution of internal variability to recent Barents-Kara sea ice loss in winter
Authors: Siew Peter Yu Feng , Wu Yutian , Ting Mingfang , Zheng Cheng , Ding Qinghua , Seager Richard
Published: March 2024

The Arctic has experienced a rapid sea ice loss in the Barents and Kara Seas in winter during the last few decades. Such sea ice loss has been attributed to anthropogenic warming and internal variability, but their relative contribution remains unclear. Using machine-learning methods and large ensemble simulations, we successfully reproduce Barents-Kara sea ice trends as the joint impact of anthropogenic and internal atmospheric variability components. Results show that the loss of Barents-Kara sea ice extent over the recent 20 years (1997-2017) is significantly enhanced by atmospheric internal variability (>50%) acting on top of anthropogenic warming. Overall, this study highlights that internal variability plays a more important role in recent winter Arctic sea ice loss than previously thought, and promotes similar machine-learning methods for attributing sea ice trends in other polar regions and seasons.
Response of plant element traits to soil arsenic stress and its implications for vegetation restoration in a post-mining area
Authors: Chen Rui , Han Lei
Published: March 2024

The ecological environment in mining area is fragile, and the carbon (C), nitrogen (N), and phosphorus (P) content of dominant plants is closely related to plant nutrient limitation, community composition and ecosystem function. Clarifying the response of dominant plants to soil properties and the corresponding trade-off mechanism are essential for rebuilding the ecological resilience and self-sustaining ability of mining areas. In order to explore the response of dominant plant element traits to soil physico-chemical properties under the stress of soil arsenic (As) pollution, an abandoned metal mining area threatened by heavy soil As pollution was selected as the research area, the soil physico-chemical properties and soil As content in different speciation, and the contents of C, N and P in dominant plants were measured. The results showed that: (1) The soil As pollution was serious in the mining area, while the contents of soil nutrient were relatively low. (2) The soil As content in different speciation affected the absorption and utilization of P by plants. (3) The dominant plants responded to soil As toxicity by allocating more nutrients to leaves to reduce toxicity and ensure growth. This study helps to reveal the nutrient driving law of plant diversity processes and community succession in heavy metal-contaminated sites and is of great significance to restore the fragile ecosystems in mining areas.
Hydrogen-driven microbial redox reactions in deep geosystems relevant for H2 storage
Authors: Krueger Martin , Dohrmann Anja
Published: March 2024

In the subsurface, biotic and abiotic processes can generate and consume hydrogen. Hydrogen has a low reduction potential and is thus a highly energetic electron donor when involved in sulfate, carbon dioxide or ferric iron reduction. Although known as important drivers for the deep biosphere, the contributions of different processes to hydrogen turnover in different geosystems still are not well understood. In context with the ongoing transformation to renewable energy resources, underground H2 storage (UHS) in deep porous or salt cavern systems came into focus. In situ microbial and geochemical reactions that consume H2 are highly relevant topics in deep biosphere research, and also are still a major uncertainty during UHS.Consequently, we studied the potential microbial hydrogen oxidation rates – combined with the possible production of metabolic products like H2S, acetic acid or CH4 - in formation fluids from natural gas fields and salt caverns, thereby considering the importance of in situ pressure and temperature conditions, fluid chemistry and mineral composition. In addition, more defined experiments were conducted with selected pure cultures representing important metabolic groups of deep biosphere microorganisms.Several original formation fluids showed immediate H2 consumption. Microorganisms oxidized hydrogen at relevant in situ pressure conditions (up to 100 bar) and tolerated dynamically changing pressure and temperature conditions. The microbial hydrogen oxidation rate was strongly dependent on H2 partial pressures and the availability of e.g. sulfate as a terminal electron acceptor. High-throughput sequencing of 16S rRNA gene amplicons indicated hydrogen oxidation by sulfate reducing bacteria to be the presumed process in the studied porous rock reservoir fluids. In addition, hydrogen turnover by methanogenic and acetogenic as well as iron-reducing microorganisms was investigated. Also, the importance of biotic reactions in relation to abiotic hydrogen turnover processes at mineral surfaces will be discussed. 
Using seismic and gravity data to constrain subglacial seafloor stratigraphy in the vicinity of the Kamb Ice Stream grounding line, Ross Ice Shelf, Antarctica
Authors: Gorman Andrew , Wilson Gary , Horgan Huw , Dunbar Gavin , Hall Caitlin , Black Jenny , Dagg Bob , Tankersley Matthew , van Haastrecht Laurine
Published: March 2024

The sedimentary units beneath the Ross Ice Shelf in the vicinity of the Kamb Ice Stream grounding line on the Siple Coast of the eastern Ross Ice Shelf play an important role in evaluating past advances and retreats of grounded ice in West Antarctica through the Quaternary. This region is an ongoing focus for drilling efforts that involve melting through the ice shelf and recovering sediments from beneath the seafloor. Seismic (and to a lesser extent gravity) methods have played a critical role in establishing a stratigraphic framework for these sediment sampling endeavours. Approximately 73 km of seismic data have been collected in this region during three seasons since early 2015, complemented by finely sampled gravity transects and a coarser regional gravity grid. Data acquisition provides localised coverage of the sub-ice-shelf ocean and sediments in a region where ROSETTA-Ice airborne-gravity data identified a gravity low. Seismic acquisition parameters have varied from survey to survey, but all involve explosive charges frozen into a hot-water-drilled holes that are recorded by conventional geophones buried in the firn. Such an acquisition configuration provides imaging of the ice shelf and underlying geological units. Processed seismic data show a mostly flat layered seafloor lying beneath the ocean cavity with at least 200 m of sub-horizontally layered sedimentary strata containing several mappable unconformities that are identified as distinct reflective horizons in the seismic data as well as reflection terminations and pinchouts in overlying and underlying units. These unconformities could correspond to past glacial erosion episodes as the position of the grounding line in this region has migrated landward and oceanward. Gravity modelling suggests that the thickness of the sedimentary basins in the region are variable beyond what we see in the shallow (few hundred metre) penetration of the seafloor.
Paleochannels and their correspondence with floods in the 21st century. Case study of Ibarra city, Imbabura, Ecuador.
Authors: Torres-Ramírez Raisa
Published: March 2024

Floods constantly occur in San Miguel de Ibarra's urban setting each year. Situated on the slopes of the Imbabura volcano, an integral component of the UNESCO Global Geopark Imbabura, this Ecuadorian city boasts an invaluable cultural and natural heritage. However, it has experienced multiple adverse impacts due to the overflow of rivers and streams. In 2022, an inventory of floods was compiled for the Geopark, revealing the persistent recurrence of this phenomenon within the city. Consequently, it became imperative to gather historical and contemporary data from diverse sources such as public institutions (GAD Ibarra 2023), digital newspapers, social networks, and aerial imagery (IGM 2014) to discern patterns and establish correlations related to these occurrences (SNGRE 2023).In this way, the acquired information spanning the period from 1965 to the present, insights were gained into the distribution of flood-prone zones and their correlation with paleochannels. Additionally, discernment was achieved regarding alterations in land-use planning attributable to urban expansion in the city, which, in turn, contributes to the heightened susceptibility to floods. This meticulous analysis unveiled specific areas within the city consistently affected by such hazards, elucidating these events' characteristics and the ensuing damage to both public and private properties. The current publication presents preliminary findings utilized in the estimation of flood risk.Keywords: Paleochannels, floods, Ibarra, Imbabura, Imbabura UNESCO GeoparkReferences:GAD Ibarra (2023) Cartography of Ibarra canton at several scalesIGM (2014) Cartography of Ibarra canton 1:5.000IGM (2023) Historical imagery of flights in Ecuador at several scalesSNGRE (2023) Data Base Events SNGRE. Period 2010 to 2023
Hadal trenches are experimental fields for geological and biological systems
Authors: Kitazato Hiroshi
Published: March 2024

Hadal trench shows integration of landscapes of plate tectonics, geological evolutions of trenches, surface and deep-water circulations, biogeochemical cycles and others.  On these environmental components, we can understand historical backgrounds of benthic organisms. I have long been worked on the deep sea benthic foraminiferal communities at the Western Pacific.  We analyzed localities of the western Pacific deep-sea, from bathyal to abyssal depths, in particular to hadal depths. Hadal foraminiferal community consists of monothalamous soft-shelled forms, agglutinated forms, porcelaneous forms, hyaline forms and large xenophyophores.  In contrast to the bathyal to abyssal depths, the hadal depths are much challenging.   Because, a lot of accidental events take place naturally, such as collisions, subductions, separations or fusion of trenches.  Trenches are fascinating natural laboratories for thinking about evolution of benthic organisms in connection to trenches.Here, I try to discuss what kind of changes should take place when trench fuse respectively.  Case studies will be given from the late Cenozoic marine strata of the Central Kwanto regions at the central Japan (Kitazato, 1997).
Reconstructing the deglacial dynamics of the northwestern Laurentide Ice Sheet 
Authors: Margold Martin , Stoker Benjamin J. , Dulfer Helen E. , Stokes Chris R. , Brown Victoria H. , Clark Christopher D. , Ó Cofaigh Colm , Evans David J.A. , Froese Duane , Norris Sophie L.
Published: March 2024

The northwestern sector of the Laurentide Ice Sheet drained ice from the Cordilleran-Laurentide ice saddle and the Keewatin ice dome towards the ice margin on the arctic continental shelf during its late local Last Glacial Maximum. The glacial geomorphological and geological record of the region documents several massive palaeo-ice streams. However, the deglacial dynamics of this sector has not yet been reconstructed in detail and questions remain about the nature of deglaciation in this region: Did ice streams operate far up-ice or were they limited to a rather narrow ice-margin zone? Was ice stagnation widespread?We reconstruct the deglaciation of the northwestern sector of the Laurentide Ice Sheet by glacial geomorphological inversion methods, based on our recent regional-scale mapping of the glacial geomorphological record. We find that the ice stream network evolved from large, marine-terminating ice streams to shorter, terrestrial ice streams. The ice drainage network experienced a reorganisation following the disappearance of the Cordilleran-Laurentide ice saddle, which previously feed ice in a northerly direction along the modern-day Mackenzie River, to more westerly ice flow sourced from the Keewatin ice dome. Deglaciation was dominated by dynamic ice retreat but we also find traces of localized ice stagnation in areas of higher ground fringing the major fast ice flow corridors. The ice flow pattern changed markedly once the ice front stepped back onto the Canadian Shield, where ice streaming largely ceased. This empirical reconstruction, fitted to the latest version of ice margin chronology, can serve as validation for numerical modelling efforts and provides information on broad-scale ice sheet dynamics during the last deglaciation. 
PredRNNv2-based drought prediction using Vegetation Health Index (VHI)
Authors: Lee Soo-Jin , Lee Yangwon
Published: March 2024

Droughts are expected to increase in both frequency and severity, exacerbated by rising global temperatures associated with climate change. These trends pose serious threats to the agricultural sector, directly impacting food production and security. Moreover, increasing drought incidence increases the risks associated with agricultural and forestry disasters, including reduced crop yields, soil degradation, and wildfires. Given these challenges, the ability to accurately monitor and predict drought conditions is critical. Effective drought forecasting plays an important role in establishing agricultural and water management policies and enabling better handling of the impacts of these events. This will enable timely and informed decisions to ensure that appropriate measures are in place to mitigate the adverse impacts of drought on ecosystems, food supplies and overall environmental health. The development and improvement of tools for drought time series forecasting is therefore essential to ongoing efforts to adapt to and mitigate the impacts of climate change. This study introduces a model designed to predict Vegetation Health Index (VHI) time series data using the Predictive Recurrent Neural Network Version 2 (PredRNN-V2). The VHI, which effectively integrates land surface temperature and vegetation status, has been widely used in drought assessment. The study focuses on South Korea, utilizing long-term weekly VHI data from NOAA for short-term prediction. The PredRNN-V2 model utilizes a network of interconnected spatio-temporal LSTM cells to learn and predict the temporal and spatial characteristics of time series images. This architecture can properly handle the complex spatial and temporal dynamics inherent in satellite-based drought data and can therefore be an effective tool for drought prediction.This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2022R1I1A1A01073185)
Henie Quadrangle (V-58, Southern Venus); Large Igneous Province Features
Authors: Boggs Katherine , Shackman Jordan , Demorcy Jerry , Pendleton Christine , Hall Jess , Chowdhury Mahdi , Bley Holly , Varga Ember , Shustova Julia , Dear Bridgette , Fontaine Parke , Dhami Lovleen , Herrington Shane , Ernst Richard , El Balil Hafida , Bethell Erin , Hamner Simon
Published: March 2024

The NASA Magellan Mission (1990 to 1994) produced a valuable resource that planetary geologists continue to use three decades later to unravel the geological characteristics of Venusian Large Igneous Provinces. The ability to be the first to map the surface of Venus is a powerful engagement tool to inspire the next generation of planetary geologists, as illustrated by the size of the Mount Royal University (MRU) Venus geological mapping team (now 25, nearly ¼ of the MRU Geology Major program). MRU is a public undergraduate university. Students are recruited out of 1st and 2nd year courses. In year one (Y1) of the research program students learn how to use the ArcGIS software while being introduced to the geological features of Venus as they map their quadrant, in Y2 or Y3 the students present a poster at an internal research day. The goal by Y4 is for these students to publish a peer-reviewed journal article. Currently one student who ran into pandemic roadblocks through high school could be published while she upgrades her marks, before she is in the MRU Geology Major Program. Such opportunities could prove to be incentives to guide other students past similar roadblocks (we will start working with local junior and high school students in the near future). Collectively we are working towards completing the geological map of the Henie Quadrangle (V-58, south Venus). Detailed mapping (at 1:500,000) revealed that lava canali extend across the entire quadrangle, with evidence for at least three generations of canali. Three canali originate from corona features (e.g. the circumferential dykes around Fotla Corona) suggesting that some canali may be linked to corona formation. The orientation of compressional wrinkle ridges (WR) in northern Henie suggest that these WRs were formed due to strain associated with the formation of the Artemis tectonomagmatic feature which is directly north of Henie. Artemis is possibly the largest such feature in the Solar System. The extent of the Artemis influence is being constrained across the Henie Quadrangle. The source of strain that formed a differently oriented WR swarm to the south of Henie is unknown. There is no evidence for the strain localization into master faults that we see on Earth. More work is needed to develop a model for the formation of the paired Latmikaik-Xacau Coronae and the associated Tellervo Chasma, Sunna-Laverna Dorsae and the Sonmunde-Mdeb-Arubani Flucti. A fissure eruption out of the Sunna Dorsa is proposed as the origin for the surrounding Arubani Fluctus.      
Concurrent Asian monsoon strengthening and early modern human dispersal to East Asia during the last interglacial
Authors: Ruan Jiaoyang , Ao Hong , Martinón-Torrese María , Krapp Mario , Liebrandh Diederik , Dekkers Mark J. , Caley Thibaut , Jonell Tara N. , Zhu Zongmin , Huang Chunju , Li Xinxia , Zhang Ziyun , Sun Qiang , Yang Pingguo , Jiang Jiali , Li Xinzhou , Song Yougui , Qiang Xiaoke , Zhang Peng , An Zhisheng
Published: March 2024

The relationship between initial Homo sapiens dispersal from Africa to East Asia and the orbitally paced evolution of the Asian summer monsoon (ASM)—currently the largest monsoon system—remains underexplored due to lack of coordinated synthesis of both Asianpaleoanthropological and paleoclimatic data. Here, we investigate orbital-scale ASM dynamics during the last 280 thousand years (kyr) and their likely influences on early H. sapiens dispersal to East Asia, through a unique integration of i) new centennial-resolution ASM records from the Chinese Loess Plateau, ii) model-basedEast Asian hydroclimatic reconstructions, iii) paleoanthropological data compilations, and iv) global H. sapiens habitat suitability simulations. Our combined proxy- and model-based reconstructions suggest that ASM precipitation responded to a combination of Northern Hemisphere ice volume, greenhouse gas, and regional summer insolation forcing, with cooccurring primary orbital cycles of ~100-kyr,41-kyr, and ~20-kyr. Between ~125 and 70 kyr ago, summer monsoon rains and temperatures increased in vast areas across Asia. This episode coincides with the earliest H. sapiens fossil occurrence at multiple localities in East Asia. Following the transcontinental increase in simulated habitat suitability, we suggest that ASM strengthening together with Southeast African climate deterioration may have promoted the initial H. sapiens dispersal from their African homeland to remote East Asia during the last interglacial.
Verification of direct release rate of oceanic 137Cs from Fukushima Daiichi Nuclear Power Plant Accident by higher resolution ocean dispersion model
Authors: Tsumune Daisuke , Tsubono Takaki , Misumi Kazuhiro
Published: March 2024

The March 11, 2011, Great East Japan Earthquake triggered accidents at the Fukushima Daiichi Nuclear Power Plant (1F NPP), releasing radioactive substances into the ocean. Sparse observational data on 137Cs in the ocean led to interpolation and simulation for a comprehensive understanding. The primary focus was on direct release, emphasizing the need for a suitable source.The direct release rate (Bq/day) was calculated by multiplying the seawater exchange flow rate (m3/day) and observed 137Cs concentration (Bq/m3). Using a mesh size of 735 m x 929 m x 8 m on the model, the seawater exchange flow rate at the release point was simulated. The 137Cs concentration relied on average observed radioactivity at 5, 6, and the south discharge canals near the 1F NPP. Direct release was estimated at 2.2x1014 Bq/day from March 26 to April 6, 2011, aligning with rates derived from other methods.The seawater exchange flow rate's dependency on the model's mesh size was acknowledged. For this estimation, a 735 m x 929 m mesh size encompassing key points was considered reasonable for the seawater exchange flow rate, given the complex transport process from the release source (Unit 2 intake) to observation points (5, 6, and the south discharge point) due to port structures.A higher resolution model with a 147 m x 186 m mesh (1/5) was used for a detailed analysis of direct release rates. The size of the sea area for determining the volume of seawater exchange flow rate can now be changed. Despite challenges in setting due to damaged ports, using the seawater exchange flow rate in a similar area as the previous resolution was deemed appropriate. The results of the validation of the release rate and the observed results by the relationship equation confirmed the consistency with the amount of seawater exchange obtained by the results of the dye tracer release experiments in the 1970s.The release of 137Cs from the 1F NPP site persists. Estimating direct release rates up to 2016, a long-term simulation with a higher resolution model was conducted for validation. Results showed the oceanic 137Cs concentration distribution influenced by coastal currents, eddies, and the Kuroshio Current, leading to spatio-temporal variability. Validation with observed annual mean concentrations revealed good agreement. The higher resolution improved coastal transport reproducibility, addressing 137Cs radioactivity underestimation at the Fukushima 2 NPP, 10 km south of the 1F NPP.
Effect of Alternative Dryland Crops on Soil Microbial Communities
Authors: Dangi Sadikshya , Allen Brett , Jabro Jay , Rand Tatyana , Campbell Joshua , Calderon Rosalie
Published: March 2024

Soil microbial community composition associated with novel rotation crops could contribute to increased yield to subsequent crops and an important factor influencing the composition of the rhizosphere microbiome. However, the effect of alternative dryland crops on soil microbial community composition is not clear in the northern Great Plains (NGP). The objective of this study therefore was to evaluate the effects of oilseed crops Ethiopian mustard (Brassica carinata A.) or camelina (Camelina sativa L.) or a 10-species forage/cover crop (CC) mix and fallow on soil microorganisms. A field study was conducted from 2014 to 2020 in the northern Great Plains, USA and was designed as a randomized complete block with three replications in a no-tillage system. Results showed that total bacterial proportion was significantly higher in camelina and fallow compared to CC and carinata. Total fungal proportion was significantly higher under CC mix compared to camelina and fallow. Fungal to bacterial ratio was significantly higher in CC and carinata compared to fallow. Fungi are often considered a good indicator of soil health while bacteria are crucial in soil functions. The changes in specific microbial communities due to crop-related alterations might play a key role in the yield of subsequent crop. Mechanisms responsible for these differences will be discussed.
Korean precipitation isotopes reflect changes in the Western Pacific Subtropical High on interannual to millennial timescales
Authors: Basu Sayak , Sinha Nitesh , Jo Kyoung-Nam , Timmermann Axel , Yang Yan , Yoshimura Kei , Cleary Daniel M. , Sharma Sahil , Wassenburg Jasper A.
Published: March 2024

Strength and shifts of the Western Pacific Subtropical High (WPSH) have a strong influence on East Asian Summer Monsoon (EASM) precipitation. How the WPSH changed in the past and its forcing mechanisms on different timescales are yet to be resolved. The role of the WPSH in modulating the East Asian climate can be traced from the oxygen isotopic composition of modern and fossil precipitation (d18Oprec) if the climatic significance of d18Oprec is adequately constrained. Here, we present a Holocene hydroclimatic analysis for the Western North Pacific (WNP) proximal region by combining observational data, a speleothem oxygen isotope (d18Ospeleo) record from South Korea and isotope-enabled transient climate model simulation. The composite d18Ospeleo record is based on two stalagmites collected from Majiri and Baeg-neyong caves. Our results shows that the interannual (based on IsoGSM simulation, 1979-2021) to interdecadal (based on i-CESM present-day run for 100 model years) variations in EASM mean amount-weighted d18Oprec values are related to the strength and zonal migration of the WPSH. The 18O-enrichment in Korean precipitation corresponds to summertime El-Niño like conditions in the tropical Pacific Ocean which suppress the convective activity in maritime continental regions and promotes the intensification of the WPSH by poleward propagating Rossby-waves. The strength of the WPSH is positively correlated to its zonal extent, and thus intensified WPSH also implies its westward migration. In this situation, the WPSH acts as a mechanical barrier to the 18O-depleted moisture contribution from the Indian Summer Monsoon (ISM) branch, and Korean precipitation receives a higher amount of moisture from the relatively 18O-enriched WNP branch. We show that the sensitivity of the Korean d18Oprec to WPSH was consistent during the pre-industrial period as well. The increasing d18Ospeleo trend from around 6 ka up to present is related to an intensified and westward migrated WPSH, as evident from the i-CESM 1.2 transient Holocene run. Mg/Ca based sea surface temperature (SST) records also confirm that a decreasing of zonal SST trend (west minus east) persisted during the Mid - Late Holocene, which established an El-Nino like condition that was favorable for the WPSH intensification.
Age of air from ACE-FTS measurements of sulfur hexafluoride
Authors: Saunders Laura , Walker Kaley , Stiller Gabriele , von Clarmann Thomas , Haenel Florian , Garny Hella , Ray Eric , Plummer David , Bönisch Harald , Engel Andreas , Laube Johannes , Sheese Patrick
Published: March 2024

The Brewer-Dobson Circulation (BDC) is one of the main determinants of trace gas distributions in the atmosphere. Climate models predict that atmospheric warming will cause the BDC to accelerate, modifying where greenhouse gases are most active and impacting the radiative properties of the atmosphere, resulting in a feedback effect. This acceleration is difficult to verify with observations because the speed of the BDC cannot be measured directly. However, changes in stratospheric transport can be identified using the stratospheric age of air, defined as the time since an air parcel entered the stratosphere from the troposphere. A decrease in age of air at higher latitudes would suggest a reduction in transit times, signifying an acceleration of the BDC. Age of air can be calculated using long-lived “clock tracers” such as sulfur hexafluoride (SF6), an industrial gas that is produced in the troposphere, has a negligible seasonal cycle, and has no stratospheric sinks. Due to its small concentrations, measurements have been historically limited, but detecting changes in age of air derived from SF6 requires a long-term, and ideally consistent (i.e., measured by the same instrument), time series. The Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) provides the longest available vertically-resolved record of SF6, spanning 2004 to the present. This study presents a new age of air product derived from the ACE-FTS SF6 dataset using an updated version of the method used for the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) SF6 dataset, which spans the 2002-2012 period. In this presentation, the method for age of air calculation will be presented along with comparisons with other age of air profile datasets derived from MIPAS and balloon measurements. The long-term trend in age of air will be estimated using this new product with the goal of corroborating the predictions made by climate models.