bluuebunny/crossref_metadata_2025 huggingface dataset:
Stable Middle Miocene seawater isotopes in the eastern North Atlantic Ocean
Authors: Haettig Katrin , Schouten Stefan , van der Meer Marcel T.J.
Published: March 2024

The Middle Miocene is a phase of gradual climate cooling, CO2 decline and major episodes of seaward Antarctic ice expansion across the Middle Miocene Climate Transition. The global benthic foraminifera oxygen isotopes (δ18Obenthic) show a long-term increase by approximately 1‰, reflecting bottom water cooling and increase in global ice volume, although the latter is subject of debate. Here, we used a relatively new proxy based on hydrogen isotopes of long-chain alkenones (δ2HC37), produced by Haptophyte algae, to reconstruct surface seawater isotopes (e.g., Schouten et al., 2006; Weiss et al., 2019; Gould et al., 2019). This proxy is, in contrast to δ18Obenthic, not temperature dependent. Enabling us to reconstruct the isotopic evolution of the surface seawater from marine sedimentary records up to 40 Million years ago.Here, we compare foraminifera based oxygen isotope and alkenone based hydrogen isotope reconstructions of seawater from a shallow sediment record covering the Middle Miocene (IODP Site U1318, 409 m water depth, eastern North Atlantic Ocean, Sangiorgi et al., 2021). The local δ18Obenthic record shows a strong long-term increase across the Middle Miocene Climate Transition in agreement with global benthic stacks. However, our reconstructed surface seawater δ2H shows no long-term increasing trend and when correcting the local δ18Obenthic record for subsurface temperature with TEXH86, the bottom seawater δ18O record also shows no long-term trend. Our findings are in line with recently published records using clumped isotope temperatures which suggest a long-term decrease in temperature during the Middle Miocene large enough to explain the trend in oxygen isotopic composition of the benthic foraminifera without the need for a change in ice volume.
Role of vegetation and soil-induced effects of microclimate on non-rainfall water inputs
Authors: Groh Jannis , Pütz Thomas , Beysens Daniel , Vereecken Harry , Amelung Wulf
Published: March 2024

Precipitation (i.e. rain, snow, hail) is the main form of water input to our ecosystem. However, depending on local climatic conditions, a significant amount of water can also be produced by various fractions of non-rainfall water inputs (NRWIs), namely dew, hoar-frost, rime, fog, and adsorption of water vapour in the soil. Such NRWIs are often neglected because they are typically small compared to daily rainfall. However, these NRWIs provide our ecosystems with additional water, which is important for the survival of the fauna and flora in the ecosystem, especially during drier periods.Although NRWIs are understood in principle, much remains to be learnt about their precise determination at the ecosystem level, their spatial and temporal distribution, and their ecological function for the ecosystem. We present a conceptual measurement setup that allows us to determine each non-rainfall water component for natural and extensive grasslands as well as for agricultural ecosystems. Our results for the experimental site Selhausen (Germany, TERENO-SOILCan) show that i) the main part of NRWI comes from dew formation, ii) the rate and frequency of dew formation differs significantly between vegetation types under similar atmospheric boundary conditions, and iii) the drivers of dew formation during a dry down period differ between ecosystems (grassland and arable land). A better understanding of these vegetation and soil-dependent effects will help us to better predict dew formation processes in our ecosystems in the future.
An ongoing lithospheric dripping process beneath Northeast China and its impact on intraplate volcanism
Authors: Lin Feiyu , Qi Liang , Zhang Nan , Guo Zhen
Published: March 2024

Unique intraplate volcano eruptions and westward volcano migration since the Oligocene are observed in NE China, an overriding continental zone tectonically controlled by the subduction of the northwestern Pacific plate and the opening of Japan Sea. Interestingly, these intraplate magmatic events occur around a subsiding basin (the Songliao Basin), but no volcanic activities have been observed within the Songliao Basin. The geodynamic mechanism responsible for these volcanoes remains unclear. To address the geodynamic process beneath NE China, numerical experiments are conducted constrained by datasets from regional reconstruction, seismic and volcanic studies. Vertical velocity field of mantle convection and lithospheric partial melting structures yielded from our numerical model show mantle upwelling and melting center migrates from the east to the west of NE China with the westward propagation of the stagnant slab, leading to the volcano migration. Also, with the subduction retreat of NW Pacific plate and the opening of the Japan Sea, significant lithospheric thickness differences between Changbaishan-Mudanjiang Region and the Songliao Basin develop, leading to lithospheric unstable dripping. This dripping structure prevents the partial melting of the lithosphere but facilitates the subsidence of the Songliao Basin in central NE China. Moreover,  the lithospheric dripping model successfully predicts upper mantle structures consistent with the proposed tomography model, the observed Moho depth, and surface topography variations. Thus, the lithospheric dripping induced by lithospheric thickness difference and the subduction of the Pacific slab provides a robust mechanism for the unique geodynamic process in NE China.
Cross-linking laboratory and field measurements to quantify the role of bubbles in air-sea CO2 exchange
Authors: Dong Yuanxu , Jähne Bernd , Marandino Christa
Published: March 2024

The global oceans are a major sink of anthropogenic carbon dioxide (CO2), playing a critical role in mitigating climate change. The ocean CO2 uptake estimate contains significant uncertainties due to a lack of mechanistic understanding of the role of bubbles in air-sea CO2 exchange. Bubbles resulting from wave breaking may mediate about 40% of the global air-sea CO2 flux.  However, bubble-mediated transfer is poorly quantified and under-represented in CO2 flux estimates. In this study, we will present a synthesis analysis of the bubble-mediated gas transfer measurements in the last decade. We show contrasting evidence regarding the importance of bubbles in the air-sea CO2 exchange, particularly in the comparison between laboratory and field measurements. This suggests a lack of mechanistic understanding of the air-sea gas exchange processes. Through innovative cross-linking of comprehensive field and laboratory observations using multiple techniques, we aim to make a step change in understanding the mechanisms of bubble-mediated transfer and reconcile field and laboratory measurements.  We also aim to provide novel parameterisations of gas transfer velocity with explicit representation of bubbles, thereby reducing uncertainty in air-sea CO2 flux estimates.
A physically-based formulation for texture evolution during dynamic recrystallization. A case study for ice
Authors: Montagnat Maurine , Chauve Thomas , Dansereau Véronique , Saramito Pierre , Fourteau Kevin , Tommasi Andréa
Published: March 2024

Dynamic recrystallization can have a strong impact on texture development during the deformation of polycrystalline materials at high temperature, in particular for those with strong viscoplastic anisotropy such as ice. Owing to this anisotropy, recrystallization is essential for ensuring strain compatibility. The development of recrystallization textures leads to significant mechanical softening, both in laboratory or natural conditions (glaciers, ice sheets). Accurately predicting ice texture evolution due to recrystallization during tertiary creep remains a challenge, yet is crucial to account adequately for texture-induced anisotropy in large-scale models of glacial ice flow. We propose a new formulation for texture evolution due to dynamic recrystallization. This formulation is physically-based on an orientation attractor which maximizes the Resolved Shear Stress (RSS) on the easiest slip system in the crystal (basal slip for ice). The attractor is implemented in an equation of evolution of the crystal orientation with deformation, which is coupled to an anisotropic viscoplastic law (Continuous Transverse Isotropic - CTI) that provides the mechanical response of the ice crystal. The set of equations, which is the core of the R3iCe open source model is solved using finite elements method with a semi implicit scheme coded using the Rheolef library. R3iCe is validated by comparison with laboratory creep data for ice polycrystals under simple shear, uniaxial compression and tension. It correctly reproduces the texture evolution and the mechanical softening observed during tertiary creep. R3iCe therefore allows predicting enhancement factors that may be implemented in large-scale flow models. Although the validation was performed for ice, the R3iCe implementation is generic and applies for any material adequately described using a CTI law.
Peculiarities and trends in the vertical ozone distribution 1973 - 2023 at Faraday/Vernadsky Antarctic station
Authors: Andrienko Yulia , Grytsai Asen , Milinevsky Gennadi , Shanklin Jonathan , Shi Yu , Yu Ruixian , Poluden Oleksandr
Published: March 2024

We processed vertical ozone distribution measurements from the Faraday/Vernadsky station made by the Umkehr method for the 1973–2023 period. Ozone profiles in this unique series of ozone observations since 1973 cover pre-ozone hole times and the ozone hole period. Umkehr data from about 1200 Dobson spectrophotometer observations was processed using the UMK92 ozone profile retrieval algorithm. The Faraday/Vernadsky station is located at the edge of the ozone hole area; therefore, the total ozone column values over the station can change rapidly. This feature is seen clearly in Umkehr profiles measured during the same day in the morning and evening. In the pre-ozone hole period 1973–1983, the ozone partial column in ozone profiles maximum varies from 134 DU/layer to 56 DU/layer with the altitude of the profile maximum at 14–18 km. Profiles in ozone hole conditions usually have two maxima. The altitude area of significant depletion in ozone partial column values between these maxima located in the usual highest ozone concentration height. The values in altitudes at expected ozone maximum drop to 14–26 DU/layer. The 50-year trend in ozone profiles in the atmosphere above Faraday/Vernadsky station from pre-ozone hole times till 2023 is described and discussed.
Multicellular eukaryotes followed:MOE or life stagnation
Authors: Duan Ruihan , Ju Pengchen , He Ruliang , Yao Jinlong , Zhao Guochun
Published: March 2024

The discovery of the fossils of decimetre-scale multicellular eukaryotes in the Mesoproterozoic from the 1.56-Gyr-old Gaoyuzhuang Formation in the North China Craton indicates that eukaryotes have evolved to a high level, but the evolution of life after it is still unclear due to the lack of definitive fossil evidence. Multi-proxies suggests that a pulsed oxygenation event was recorded during1.56-1.57 Ga, but the subsequent ocean oxygen levels are unequivocal. Here we report I/(Ca+Mg) ratios, carbonate C-O isotopes, and Ce anomaly across the ca. 1.56-1.50 Ga in the North China Platform. The results showed that the evolution of ocean oxygen content could be divided into four stages: (1)The δ13Ccarb values remained stable at 0‰ , and the I/(Ca+Mg) ratios was near detection limit, with no Ce anomaly from 1.56 to 1.53Ga, indicating that the ocean was anoxic; (2)The I/(Ca+Mg) ratios increased to 1.2μmol/mol with an excursion from 0‰ to -2.6‰ negative δ13Ccarb anomaly, and a negative Ce anomaly to 0.56 in 1.52Ga, which may be the result of the oxidation of the dissolved organic carbon(DOC) in the ocean, and the ocean changed from anoxic to oxic;(3) The C isotope composition 0‰ , with I/(Ca+Mg) ratios maintained at 0μmol/mol-0.5μmol/mol, and there was no Ce anomaly in 1.51Ga. Oxygen consumption through oxidation of DOC may have quickly lowered marine O2 levels to suboxic.(4) A positive shift in  δ13Ccarb from 0 ‰ to +2.1‰, and the I/(Ca+Mg) increased to 1μmol/mol, without obvious Ce anomaly, which may be a certain degree of biological flourishing leading to the increase of oxygen content in the ocean. Although the ocean in 1.52Ga was oxic, the oxygen levels were low, which may be a key factor restricting the evolution of eukaryotes.
The long-lasting earthquake swarm leading up to the 2024 M7.6 Noto-Hanto earthquake, Japan
Authors: Kato Aitaro , Nakagawa Shigeki
Published: March 2024

An intense earthquake swarm has persisted for more than three years within a 20 km × 20 km area beneath the northeastern tip of the Noto Peninsula, central Japan since November 2020. The largest magnitude for each year from 2021 to 2023 increased to 5.1, 5.4, and 6.5 by the end of 2023. On January 1st, 2024, an M7.6 earthquake rupture nucleated within the swarm area and propagated bilaterally toward ENE and WSW directions along multiple faults. Globally, it is rare that the long-lasting seismic swarm preceded such a large event. We have analyzed the long-term continuous seismic waveforms to create a more precise earthquake catalog associated with this earthquake sequence. Based on this catalog, we have explored the spatial-temporal evolution of the seismicity before the M7.6 event. Note that the foreshock sequence, including a M5.7 event, started approximately 1 hour before the M7.6 event close to the hypocenter. The M7.6 nucleated from the deepest side of one of numerous planer clusters that were dominantly dipping toward the southeast direction. Several previous studies using seismic and geodetic data suggest that the long-lasting earthquake swarm has been driven by upward fluid flow along pre-existing cracks/faults in the crust (e.g., Nishimura et al. 2023). Especially, Kato (2024, doi:1029/2023GL106444) recognized a rapid upward migration of the immediate aftershocks following the 2023 M6.5 and M5.9 events and implied fault-valve behavior that might be driven by upwelling of crustal fluids along the intensely fractured and permeable fault zones via the dynamic ruptures. If fluids could migrate along pre-existing faults, fault strength would be reduced by lubrication. In addition, the long-lasting intense seismicity and slow deformations detected by GNSS network have partially released the accumulated elastic stress in the swarm area, resulting in stress loading onto nearby fault segments. The strength of the faults gradually decreased, and the stress was partially released over three years, which may have triggered the latest M7.6 earthquake.
Building A Trustworthy Data Repository for Australian Geoscience Research Communities
Authors: Devaraju Anusuriya , Stuart Woodman , Bradley Sam , Fazio Vincent , Taherifar Neda , Motevalli Benyamin , Klump Jens , Wyborn Lesley , Farrington Rebecca
Published: March 2024

AuScope Australia (https://www.auscope.org.au/) focuses on delivering data, services, and tools to support the future research of the Australian geoscience research community. As a component of the “Data Lens” of the AuScope Downward-Looking Telescope, the AuScope Discovery Portal (https://portal.auscope.org.au/) harvests metadata from affiliated data catalogues to support more comprehensive access. Over time, it has become apparent that the data repositories offered by the AuScope partners and universities need to be improved for curating data from the AuScope projects. Many do not provide structured metadata suitable for harvesting into the Discovery Portal and offer limited data discovery and retention support. Consequently, most institutional data repositories do not support AuScope’s strategy toward making all data from AuScope projects or data collected with AuScope-funded instruments compliant with the FAIR (Findable, Accessible, Interoperable, and Reusable) Guiding Principles for both humans and machines (Wilkinson et al., 2016). The goal of the AuScope Data Repository is to preserve and offer continued access to data from its communities (e.g., NCRIS-funded data projects and Australian Geoscience research communities) working on fundamental geoscience questions and grand challenges, including climate change, natural resources security and natural hazards. Datasets submitted to the repository will be made openly available where appropriate, with attributions to promote open science. The repository is essential for geoscience research innovation in support of the AuScope 5-Year Investment Plan and Australian Academy of Science Decadal plan for Australian Geoscience: Our Planet, Australia's Future. This presentation will cover the repository’s scope and design, including non-technical (e.g., practices, governance, and engagement) and practical aspects of the repository (e.g., persistence identification, data discovery, interoperability, workflows and security and architectural requirements). We discuss the key considerations when setting up a data repository for scientific communities. The first release of the repository is now available online to gather early feedback from the selected AuScope data providers and project affiliates. We will summarize the presentation with the next steps of the development process, including engagement activities and documented data practices.
Water availability controls seasonal shifts in root growth timing
Authors: Nair Richard , Strube Martin , Schrumpf Marion , Mirco.MIGLIA Mirco
Published: March 2024

Root growth dynamics are difficult to observe both on phenological and sub-daily scales as manual destructive measurement is high effort and prone to error. Close synchrony and prescriptive links with more easily observed above ground dynamics on seasonal timescales are often assumed, affecting interpretation of greenhouse gas fluxes without a solid basis in observational whole system data. Increasingly, we now recognize that seasonal root growth can be desynchronized from leaves, causing a rethink of these relationships. However sub-daily patterns are still opaque because measuring field root dynamics remains extremely difficult, especially this frequently. This is even more true over sustained, seasonal timescales where controls and dynamics may shift. Potential drivers of diel growth include photosynthesis (carbon), cell turgor (water), environmental temperature, and intrinsic circadian rhythms. Controls may differ through time, and between organs, and are difficult to separate under natural conditions in observational studies.We use automated minirhizotrons and neural networks for image interpretation to bypass many previous observational constraints and gather resampled root dynamics data at up to sub-daily resolution. We observing roots four times a day for two years, every day, in a temperate grassland in Germany. We observed a strong underlying cell turgor signal in these uniquely frequent observations, visible through diel oscillation of root width. Removing this signal, we found root growth generally had little diel pattern except in periods of leaf-level water stress. Here roots consistently grew during the day and not at night. We examine the reasons for this switch in diel dynamics through the lens of potential environmental, water and carbon control. We found little evidence for direct temperature limits in our system. Instantaneous C supply, which should increase as canopies develop through the season, also did not appear to impact rate of growth despite previous isotope tracer studies showing a tight temporal coupling between carbon assimilation and bulk soil CO2 efflux. Our observations point towards water and cell turgor as the main control on root growth timing variation in contrast to the carbon-centric view of plant-soil system functioning indicated by pulse chase experiments. Underlying growth dynamics and their controls should be considered when interpreting whole system fluxes, and their sensitivity to environmental conditions in our dynamic and changing world.  
Effects of efforts to reduce air pollutants such as PM2.5 on increasing surface ozone concentrations
Authors: Jeong Peel-Soo , Wang Kyung-Hui , Son Eun-Seong , Kim Hyeun-Soo , Han Seung-Hee , Yun Hui-young
Published: March 2024

Global climate change and increased air pollutant emissions in East Asia have led to an increase in tropospheric ozone concentrations, especially in South Korea.In order to reduce both particulate matter (PM2.5) and ozone concentrations in Korea, efforts to reduce emissions of precursors (NO2, VOCs) and particulate matter have been implemented, and as a result, the concentration of particulate matter has been continuously reduced. However, contrary to expectations, ozone concentrations have continued to increase, and the trend is that both the annual average concentration as well as the number and duration of high concentration ozone events are increasing.Factors affecting tropospheric ozone production are very diverse and complex, including climate change, emission characteristics of precursors (NOx, VOCs) and resulting changes in atmospheric chemical species, changes in chemical reactions due to changes in atmospheric aerosols, natural source VOCs, long-range transport of ozone and precursors, geography and topography, and differences in ozone production characteristics between countries, cities, and regions.While there are global influences such as climate change and long-distance transport of high ozone concentrations from neighboring countries that are responsible for the increase in ozone concentrations in Korea, there is also evidence from various observations that suggests that due to the non-linear relationship between ozone production and its precursors, air pollutant reduction efforts are contributing to the increase in ozone concentrations by changing the local atmospheric chemical composition.The study analyzes changes in ozone precursor emissions, atmospheric chemical composition, and aerosol concentrations resulting from efforts to reduce various air pollutants, including particulate matter and ozone, and ultimately provides insight into how air pollution mitigation efforts are contributing to increased ozone concentrations.The insights are expected to clarify existing understanding of the limiting conditions and chemical reactors for NOx and VOCs involved in ozone formation in urban areas, and to provide evidence and ideas for further understanding. AcknowledgmentsThis research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute(KEITI) funded by the Ministry of Environment(MOE)
Automated mineralogy as a key technology toward zero-waste mining – The EXCEED project
Authors: Lavikko Sonja , Dehaine Quentin , Prado Araujo Fernando , Muchez Philippe
Published: March 2024

The increasing demand for critical raw materials (CRMs) linked to the energy transition, Europe’s reliance on a few third countries (incl. China) for the supply of these combined with increased ESG issues calls for a new mining paradigm: i.e., responsible, zero-waste, multi-metal/mineral mining. Li-hard rock deposits (pegmatites and rare-metal granites) are perfect candidates for such an approach, where, besides lithium, numerous by-products including industrial minerals (quartz, feldspar, micas) and CRMs (Nb, Ta, and so forth) could be potentially extracted. To assess whether these by-products can be recovered during Li production requires a mineral-centric, integrated geometallurgical approach. Automated mineralogy is a key technology for such an approach. Determining how to utilize the secondary material streams and recovery of the by-products relies on the knowledge of the material, its chemical composition, particle size, crystal structure and texture to grain size, liberation grade and mineral associations. In this study, four European lithium mine projects, two pegmatite projects (Keliber, Finland and Savannah, Portugal) as well as two rare-metal granite (RMG) projects (Beauvoir, France and St Austell, UK), are investigated. Different ore types as well as process samples (concentrates, residues, and tailings) were investigated to assess the by-product potentials of industrial minerals, CRM’s as well as the status and behavior of potentially harmful elements (PHEs) throughout the processing flowsheet. Gathering of all this information is started by the Extended BSE Liberation Analysis (XBSE_STD) and Grain-Based X-ray Mapping (GXMAP) measurements with the FEI Quanta 650F, an automated Scanning Electron Microscope equipped with a field emission gun electron source, two Energy Dispersive X-ray spectrometers (EDX) (Bruker X-Flash 6130), and FEI’s Mineral Liberation Analyzer (MLA) quantitative mineralogy software v. 3.1.4. Additional data is collected with Micro-XRF Bruker M4 Tornado plus with AMICS. Details are further studied with additional methods, such as X-ray powder diffraction, Inductively Coupled Plasma Optical Emission spectroscopy, Electron Probe Micro-Analyses, Laser ablation ICP-MS, and X-ray Fluorescence measurements.  To define how the ore properties and the PHE/CRM deportment affect the options for usability, a comprehensive geometallurgical assessment will be conducted starting from collecting the basic mineralogical data to creating process flowsheet options and predicting theoretical process performance. These results are then to be tested at the lab and pilot scale according to the produced process protocols to be validated.  
Quaternary volcanism in southeastern Tibetan Plateau: A record of stagnant oceanic slab in the mantle transitional zone
Authors: Kang Huan , Zhao Yongwei , Zhang Xiaoran , Zhang Liyun , Zhang Huiping , Zou Haibo
Published: March 2024

The Tibetan lateral mantle flow bears considerable significance in deciphering the material movement mechanisms within global plate convergence zones. However, the front edge of this mantle flow is unclear. Here we conduct petrological, geochronological, mineralogical, geochemical and Sr-Nd-Pb isotopic investigations on Quaternary intracontinental alkali basalts from the southwestern Yunnan (the south of 27°N), to determine the source characteristics and geodynamic mechanisms of the Quaternary alkali basalts in southeastern Tibetan Plateau and to trace the recent Tibetan mantle flow. Alkali basalts in the region are mainly basanite and trachybasalt with eruptions during the Pleistocene epoch. They possess a highly incompatible elemental and radiogenic Sr-Nd-Pb isotopic composition similar to those of the Ocean Island Basalts, consistent with melts derived from asthenospheric mantle with low-degree partial melting. Calculated magma-water contents of regional alkali basalts range from 1.32 ± 0.48 wt.% to 2.23 ± 0.18 wt.%, corresponding to 269 ppm to 3591 ppm water contents of their mantle source, which are significantly higher than that of the normal upper mantle (i.e., 50–250 ppm). Quantitative trace-element modelling and dramatic variations in oceanic crust-sensitive indicators such as Eu/Eu*, Sr/Sr*, Ce/Pb, (Nb/Th)N-PM and (Ta/U)N-PM indicate variable contributions of upper and lower oceanic crust to magma sources. Systematic examinations of petrological, geochemical, and geophysical evidence reveal that the temporary small-volume Quaternary volcanism in southeastern Tibetan Plateau is not related to Tibetan southeastward mantle flow but is primarily attributed to stagnant Neo-Tethyan slab in the mantle transition zone.
Fractal approach in the Analysis of climate change due to the ozone layer hole
Authors: Murugan Meenakshi
Published: March 2024

The ozone layer acts as the planet's natural sunscreen, protecting people, plants, and animals from harmful UV-B rays. In Antarctica, British scientists discovered the hole in the ozone layer in 1985. The effects of climate change have been experienced by all living hoods through various kinds of natural calamities due to this hole. Many researchers dedicated their time to solving this problem and saving the planet. This article explores Antarctica's post-1985 climate changes.  The authors have to Investigate the time series data for the global temperature, precipitation, and Antarctica ice sheet mass balance through analysis utilizing the fractal analysis tool.  Additionally, the nonlinear dynamical data's chaotic feature is verified.
Ecological environment quality evaluation of the gully area in the Loess Plateau based on remote sensing ecological index
Authors: Zhang Yujie , Zhang Xiaoping , He Jie , He Liang , Sun Weinan , Geng Wenliang , Wang Haojia , Wang Yichen , An Zefeng , Yu Kaiyang , Liu Xuanhao
Published: March 2024

Abstract: As the fundamental foundation for human survival and development, the ecological environment is an important guarantee for social progress. With the accelerated development of society, the impact of human activities on the ecological environment has become increasingly significant. Fu County (4,182 km2) is located in the gully area of the Loess Plateau, an important ecological security barrier in the north of China. Clarifying the current situation of the ecological environment and the temporal and spatial changes of ecological environment quality in Fu County is conducive to the construction of ecological civilization. It provides scientific support to improve ecological quality.Based on the remote sensing images of Landsat in Fu County from 1992 to 2019, we considered four indexes of Normalized Difference Vegetation Index (NDVI), Tasseled Cap Transformation Humidity Index (Wet), Normalized Difference Bare Soil Index (NDBSI), and Land Surface Temperature (LST) to represent greenness, humidity, dryness and heat of the environment. The principal component analysis was uesd to establish a remote sensing ecological index model (RSEI). And then we evaluated the ecological quality in the area in the past 30 years.The results showed that: (1) The average correlation between RSEI and four indexes was 0.874, which means RSEI can comprehensively reflect the ecological environment quality status of the study area compared with a single index. (2) The regional mean values of RSEI in Fu County showed an upward trend from 0.621 to 0.806 between 1992 and 2019, and the increase in ecological environment quality gradually increased from northwest to southeast of the county. (3) The increasing area and magnitude of the ecological level of the county from 1992 to 2019 were much greater than the decling area and magnitude. Over the past 30 years, the relatively sparsely populated townships of Zhiluo, Niwu and Zhangjiawan, which have a high degree of vegetation cover, have always been in a better state, while the densely populated townships of Jizixian, Jiaodao and Yangquan has always been poor. From the perspective of the degree of change in the quality level of the ecological environment, all townships have been improved to different degrees, and the improvement is the most obvious in Jizixian Town, Jiaodao Town and Yangquan Town.The improvement of ecological environment quality level from good to excellent is probably because that the implementation of many ecological projects and the increase in rainfall, and the decrease in bare soil area and surface heat decreased in Fu County in the past 30 years.This study can provide method reference and data support for ecological environment monitoring, governance and protection. Keywords: Fu County; Ecological environment quality evaluation; RSEI; Dynamic monitoring
Recover the Water Content of Mid-Ocean Ridge Basalts by a Machine Learning Method
Authors: Zhou Jingjun , Liu Jia , Xia Qunke , Su Cheng , Kuritani Takeshi , Hanski Eero
Published: March 2024

Water's impact on the physicochemical attributes of mantle rocks makes it a pivotal factor in mantle evolution. Mid-ocean ridge basalts (MORBs) are essential for analyzing the upper mantle's composition, yet many global MORB samples lack direct water content assessment. The common method, using a correlation between H2O and trace elements like Ce to estimate MORB water contents, often presume a constant H2O/Ce ratio. Sometimes this assumption is unreliable due to the heterogeneity in H2O/Ce ratios, even within short ridge segments. For addressing this gap, we utilize compositional data from 1,467 global MORB glasses with measured water contents to develop a Random Forest Regression model. This machine learning-based model can predict water concentrations of MORB glasses based on major and trace element data, without the need for a fixed H2O/trace element ratio. Our model accurately recovers water contents of MORB glasses, showing comparable precision to traditional analytical methods. Applying this model to 1,931 MORB glass samples has significantly expanded the global MORB water content database, revealing the widespread presence of high-water MORBs. Importantly, this innovative approach enables the exploration of water content in MORBs from regions previously without such data, like the Chile Ridge and the Pacific-Antarctic Ridge. Moreover, it allows us to deduce variations of water contents of MORB sources by applying the model to transform fault samples, thereby offering novel insights into the dynamics of the mantle.
Automatic Determination Of P-Wave Arrival Time Using The Initial Power Of The P-Wave: A Case Study In Western Java
Authors: Kadnan Kadnan , Djuhana Dede , Handoko Djati , Florida Riama Nelly
Published: March 2024

Determining the arrival time of P waves is crucial in the context of earthquake early warning. Accuracy and calculating time play an important role in the earthquake parameter prediction. By using the initial power of the P-wave (IPP), STA/LTA, and artificial neural network, the arrival time of the P wave has been determined. 4,482 earthquake signals which occurred between 2021 to 2023 in the western of Java obtained by accelerometer were carefully investigated. The arrival time calculated by using Initial of P-wave (IPP) then compared with traditional STA/LTA picking and artificial neural network (ANN). Interestingly, IPP method can reduce background noise better than the other implying very clear P-wave to be proceed. It is found that IPP method exhibit less deviation, higher accuracy, and more precise suggesting candidate to apply as earthquake early warning system. This research contributes the reliability of seismic monitoring, thereby enhancing our ability to provide timely and accurate earthquake predictions for enhanced public safety.
Understanding the variable impact of point sources on headwater stream water quality
Authors: Spill Caroline , Ditzel Lukas , Gassmann Matthias
Published: March 2024

In rural areas, point sources like wastewater treatment plants or combined sewer overflows are frequently overlooked or only simplistically considered in analyses of whole watersheds. The lack of available data and the difficulty of tracing hydrochemical signatures of (reactive) nutrients measured at the outlets of larger areas back to their origin are common reasons for that. The extent to which these sources influence nutrient dynamics in water bodies and how they interact with nutrients from diffuse sources has been examined in only a few studies.As part of our study, we installed a comprehensive measurement setup in a selected rural watershed where a local wastewater treatment plant and combined sewer overflows discharge into a small river. To capture the dynamics of these point sources, pressure sensors, water quality probes, and automatic samplers were installed shortly after the treatment plant. The outlet was sampled weekly. Additional samples were taken upstream of the treatment plant and downstream of our monitoring station, to capture in-stream nutrient transformation.In contrast to the common assumption that the influence of small treatment plants can be considered constant, the water quality of the treated wastewater undergoes significant fluctuations, especially during base flow. Comprehensive statistical analyses show that the treatment plant significantly influences the concentration-discharge relationship in the water body and is responsible for a large portion of nutrient loads. In the water body itself, ammonium constitutes half of the inorganic nitrogen It is detectable only downstream of the wastewater treatment plant outlet, where it undergoes rapid nitrification. During precipitation events, a complex interaction of the treatment plant, combined sewer overflows, and diffuse sources was observed. In particular, the increasing input of ammonium and ortho-phosphate leads to an increase in exported concentrations and loads of these nutrients. At the same time, the system is characterized by frequent activation of combined sewer overflows. Our investigations show that the effects of wastewater treatment plants in rural areas are more differentiated and extensive than commonly assumed. At the same time, there is still a high potential to reduce the discharge of nutrients from point sources and, thus, the discharge of nutrients from low order catchments.
Downward counterfactual search for cascading losses
Authors: Woo Gordon
Published: March 2024

Loss exceedance curves have fat tails arising from cascading losses.  Even though such losses are rare, insight can be gained by considering alternative downward counterfactual realizations of historical events.  The use of downward counterfactuals provides a methodology for constructing climate change storylines (e.g. Climate Risk Management, 2021).The downward counterfactual search for cascading losses can identify potential tipping points for disasters.  Such tipping points can arise from the perturbation of a historical system state through additional climate forcing, combined with human factors, such as human error, negligence or malicious action.   Examples are given of how lessons learned from historical compound events, e.g. wind and heatwave, might have averted disaster.  The Californian utility, Pacific Gas & Electric (PG&E), narrowly missed liability for the 2017 Tubbs Fire in Northern California.  Increased inspection of their electricity power lines would have mitigated the risk of liability from future wildfires.  The following year, the Camp fire occurred, the deadliest and most destructive in Californian history.  PG&E were indicted for repeatedly ignoring warnings about its aging power lines and faulty maintenance, and in early 2019, PG&E were forced to file for Chapter 11 bankruptcy.On 9 September 2023, Storm Daniel transitioned into a Mediterranean tropical cyclone, and made landfall near Benghazi in Libya, the following day.  The intense rainfall caused the collapse of the two Wadi Derna dams on 11 September, and the devastation of Derna.  Counterfactual analysis would have given prior warning. A Libyan hydrologist had pointed out in 2022 that the 1959 storm would have caused the failure of the dams, had they existed then.Exploration of downward counterfactuals would augment societal resilience against climate extremes and compound events.   
Analyzing Earthquake's Onset-Magnitude Correlation Using Machine Learning and Simulated and Seismic Data
Authors: Rodda Gopala Krishna , Tal Yuval
Published: March 2024

Exploring the potential relationship between an earthquake’s onset and its final moment magnitude (Mw) is a fundamental question in earthquake physics. This has practical implications, as rapid and accurate magnitude estimation is essential for effective early warning systems.This study employs a novel approach of a hybrid Convolutional Neural Network (CNN) - Recurrent Neural Network (RNN) models to estimate moment magnitude from just the first two seconds of source time functions (STFs), which is significantly shorter than the entire source duration. We use STFs of large earthquakes from the SCARDEC database, which applies a deconvolution method on teleseismic body waves, considering only events with a Mw > 7 and an initial STF value smaller than 1017 Nm/s to avoid potential bias. Additionally, we incorporate STFs from physics-based numerical simulations of earthquake cycles on nonplanar faults, varying in roughness levels and fault lengths. These simulations exhibit substantial variability in earthquake magnitude and slip behavior between events. The reported methodology uses the information contained in the initial characteristics of the STF, its temporal derivative, and the associated seismic moment, capturing the valuable insights present in the initial energy release about the final moment magnitude.For the simulated data, the CNN-RNN model demonstrates a good correlation between the initial 2 seconds of the STF and the final event magnitude. Correlation coefficients close to 0.8 and root mean squared errors (RMSE) around 0.25 for magnitudes between 5 and 7.5 showcase the model’s ability to learn and generalize effectively from diverse earthquake scenarios. While results for natural earthquakes from the SCARDEC database remain promising (RMSE of 0.27), the correlation coefficient is lower (0.31), suggesting a weaker relationship than simulated data. This discrepancy might be attributed to the narrower band of magnitudes (7 to 7.5) within SCARDEC data used here, potentially limiting the model’s ability to discern subtle variations and establish a stronger correlation. Further, as an earthquake's fractional duration, 2 sec/source duration, increases, the model's error consistently decreases as expected. Finally, most predictions fall within a narrow range of 1% error, and nearly 90% of samples across diverse durations satisfy a set 5% error threshold. This consistent performance of the hybrid CNN-RNN model across varying source durations, magnitude ranges, and fault characteristics underscores the model's adaptability and robustness in handling diverse earthquake scenarios. While we mostly use here STFs from simulated earthquakes, continuous learning and refinement against reliable and diverse STFs obtained from teleseismic data, when available, are key to enhancing the potential of these CNN-RNN models for a better understanding of the onset-magnitude correlation in natural earthquakes.
Analytical Model of Magnetospheric Whistler Mode Waves Based on Cubic Splines
Authors: Santolík Ondřej , Kolmašová Ivana , Taubenschuss Ulrich , Turčičová Marie , Hanzelka Miroslav
Published: March 2024

We model the behavior of long-term averages of whistler mode waves in the inner magnetosphere as a function of position and geomagnetic activity. We analyze a combined data set of the Van Allen Probes and Cluster missions to construct empirical analytic expressions defined in a 4-dimensional parametric space of magnetic local time, absolute value of magnetic latitude, McIlwain's L parameter, and Kp index. We use a simple but sufficiently general functional form based on polynomial cubic splines with linear extrapolation outside of the approximation interval. The model clearly reproduces the strong influence of external driving in the equatorial region and a weak response of chorus amplitudes at high latitudes to the geomagnetic activity.
How glacial landscape evolution has impacted Scandinavian Ice Sheet dynamics and dimensions
Authors: Jungdal-Olesen Gustav , Andersen Jane Lund , Born Andreas , Pedersen Vivi Kathrine
Published: March 2024

The topography and bathymetry of Scandinavia have been molded by ice across numerous glacial cycles during the Quaternary. In this study, we explore the interplay between this changing morphology and the Scandinavian Ice Sheet (SIS). Using a higher-order ice-sheet model, we simulate the SIS over a glacial cycle on three different topographies, representing different stages of Quaternary glacial landscape evolution. By subjecting these simulations to identical climate conditions, we isolate the effects of landscape morphology on the evolution and dynamics of the ice sheet. Our findings indicate that early Quaternary glaciations in Scandinavia were restricted in both extent and volume by the pre-glacial bathymetry. It was only as glacial deposits filled a depression in the North Sea and expanded the Norwegian shelf that the ice sheet could expand further. This is illustrated by our middle to late Quaternary simulation (around 0.5 million years ago), where a filled bathymetry facilitated both a faster and further southward expansion, resulting in a relative increase in both ice-sheet volume and extent. Additionally, our study highlights that the formation of The Norwegian Channel acted as a barrier to southward ice-sheet expansion. This limitation only allowed the ice sheet to advance into the southern North Sea close to glacial maxima. Notably, our experiments suggest that distinct segments of The Norwegian Channel may have formed in different stages during glacial periods after the bathymetry was sufficiently filled with glacial sediments. These results underscore the importance of considering changes in landscape morphology over time when interpreting ice-sheet history based on ice-volume proxies and when interpreting climate variability from past ice-sheet extents.
Structure and functioning of soil animal food webs across temperate and tropical forests
Authors: Potapov Anton , Thurikov Sergey , Scheu Stefan , Tiunov Alexei
Published: March 2024

Soil biogeochemical cycles are regulated by soil food webs. However, variation of soil food web structure and functioning across key environmental gradients remains unknown, hampering generalisations of any suggested links between fauna and biogeochemistry. Here, we used two complementary approaches to quantify soil animal food web variation across forest types, from southern taiga to rainforests. First, we applied the energy flux approach to explore patterns of energy distribution across micro-, meso- and macrofauna. We showed that tropical soil food webs have consistently higher energy flux, proportionally higher predation rates (31 vs 18-27% of the total energy flux) and relied more on the plant energy channel (21 vs 10%), but less on the bacterial (5 vs 9-18%) and litter energy channels (14 vs 18-32%), than temperate soil food webs. Second, we compiled a large database (>8000 records) of stable isotope composition of soil animals to see how detritivory and microbivory in soil animal communities change with environmental temperature and litter quality. Despite little effect of temperature, shift in 15N concentrations suggested that in most cases low litter quality (high %C and low %N) result in a switch from feeding directly on litter to feeding on microorganisms. Thus, soil animals change their functional role from competitors to consumers of microbes. Our studies show how the functioning of soil animal food webs changes across biomes with different climate and litter quality and summarise functional roles animals play in different biomes.