bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deep‐Learning Based Causal Inference: A Feasibility Study Based on Three Years of Tectonic‐Climate Data From Moxa Geodynamic Observatory
Authors: Ahmad Wasim , Kasburg Valentin , Kukowski Nina , Shadaydeh Maha , Denzler Joachim 
Published: October 2024

AbstractHighly sensitive laser strainmeters at Moxa Geodynamic Observatory (MGO) measure motions of the upper Earth's crust. Since the mountain overburden of the laser strainmeters installed in the gallery of the observatory is relatively low, the recorded time series are strongly influenced by local meteorological phenomena. To estimate the nonlinear effect of the meteorological variables on strain measurements in a non‐stationary environment, advanced methods capable of learning the nonlinearity and discovering causal relationships in the non‐stationary multivariate tectonic‐climate time series are needed. Methods for causal inference generally perform well in identifying linear causal relationships but often struggle to retrieve complex nonlinear causal structures prevalent in real‐world systems. This work presents a novel model invariance‐based causal discovery (CDMI) method that utilizes deep networks to model nonlinearity in a multivariate time series system. We propose to use the theoretically well‐established Knockoffs framework to generate in‐distribution, uncorrelated copies of the original data as interventional variables and test the model invariance for causal discovery. To deal with the non‐stationary behavior of the tectonic‐climate time series recorded at the MGO, we propose a regime identification approach that we apply before causal analysis to generate segments of time series that possess locally consistent statistical properties. First, we evaluate our method on synthetically generated time series by comparing it to other causal analysis methods. We then investigate the hypothesized effect of meteorological variables on strain measurements. Our approach outperforms other causality methods and provides meaningful insights into tectonic‐climate causal interactions.
Permafrost Region Greenhouse Gas Budgets Suggest a Weak CO2 Sink and CH4 and N2O Sources, But Magnitudes Differ Between Top‐Down and Bottom‐Up Methods
Authors: Hugelius G. , Ramage J. , Burke E. , Chatterjee A. , Smallman T. L. , Aalto T. , Bastos A. , Biasi C. , Canadell J. G. , Chandra N. , Chevallier F. , Ciais P. , Chang J. , Feng L. , Jones M. W. , Kleinen T. , Kuhn M. , Lauerwald R. , Liu J. , López‐Blanco E. , Luijkx I. T. , Marushchak M. E. , Natali S. M. , Niwa Y. , Olefeldt D. , Palmer P. I. , Patra P. K. , Peters W. , Potter S. , Poulter B. , Rogers B. M. , Riley W. J. , Saunois M. , Schuur E. A. G. , Thompson R. L. , Treat C. , Tsuruta A. , Turetsky M. R. , Virkkala A.‐M. , Voigt C. , Watts J. , Zhu Q. , Zheng B. 
Published: October 2024

AbstractLarge stocks of soil carbon (C) and nitrogen (N) in northern permafrost soils are vulnerable to remobilization under climate change. However, there are large uncertainties in present‐day greenhouse gas (GHG) budgets. We compare bottom‐up (data‐driven upscaling and process‐based models) and top‐down (atmospheric inversion models) budgets of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) as well as lateral fluxes of C and N across the region over 2000–2020. Bottom‐up approaches estimate higher land‐to‐atmosphere fluxes for all GHGs. Both bottom‐up and top‐down approaches show a sink of CO2 in natural ecosystems (bottom‐up: −29 (−709, 455), top‐down: −587 (−862, −312) Tg CO2‐C yr−1) and sources of CH4 (bottom‐up: 38 (22, 53), top‐down: 15 (11, 18) Tg CH4‐C yr−1) and N2O (bottom‐up: 0.7 (0.1, 1.3), top‐down: 0.09 (−0.19, 0.37) Tg N2O‐N yr−1). The combined global warming potential of all three gases (GWP‐100) cannot be distinguished from neutral. Over shorter timescales (GWP‐20), the region is a net GHG source because CH4 dominates the total forcing. The net CO2 sink in Boreal forests and wetlands is largely offset by fires and inland water CO2 emissions as well as CH4 emissions from wetlands and inland waters, with a smaller contribution from N2O emissions. Priorities for future research include the representation of inland waters in process‐based models and the compilation of process‐model ensembles for CH4 and N2O. Discrepancies between bottom‐up and top‐down methods call for analyses of how prior flux ensembles impact inversion budgets, more and well‐distributed in situ GHG measurements and improved resolution in upscaling techniques.
TANAGER: Design and Validation of an Automated Spectrogoniometer for Bidirectional Reflectance Studies of Natural Rock Surfaces
Authors: Rice Melissa , Lapo Kristiana , Hoza Kathleen , Cloutis Ed , Kraft Mike , Mulcahy Sean , Applin Dan , Theuer Samantha 
Published: October 2024

AbstractLaboratory measurements of reflectance spectra of rocks and minerals at multiple viewing geometries are important for interpreting spacecraft data of planetary surfaces. However, efficiently acquiring such measurements is challenging, as it requires a custom goniometer that can accommodate multiple, bulky samples beneath a movable light source and detector. Most spectrogoniometric laboratory work to date has focused on mineral mixtures and particulates, yet it is also critical to characterize natural rock surfaces to understand the influence of texture and alteration. We designed the Three‐Axis N‐sample Automated Goniometer for Evaluating Reflectance (TANAGER) specifically to rapidly acquire spectra of natural rock surfaces across the full scattering hemisphere. TANAGER has its light source and the spectrometer's fiber optic mounted on rotating and tilting arcs, with a rotating azimuth stage and six‐position sample tray, all of which are fully motorized and integrated with a Malvern PanAnalytical ASD FieldSpec4 Hi‐Res reflectance spectrometer. Using well‐characterized color calibration targets, we have validated the accuracy and repeatability of TANAGER spectra. We also confirm that the system introduces no discernible noise or artifacts. All design schematics and control software for TANAGER are open‐source and available for use and modification by the larger scientific community.
Assessing the Precision and Accuracy of Foraminifera Elemental Analysis at Low Ratios
Authors: Lu Wanyi , Guo Weifu , Oppo Delia W. 
Published: October 2024

AbstractThe minor and trace element compositions of biogenic carbonates such as foraminifera are important tools in paleoceanography research. However, most studies have focused primarily on samples with element to calcium (El/Ca) ratios higher than the El/Ca range often found in benthic foraminifera. Here, we systematically assess the precision and accuracy of foraminifera elemental analysis across a wide range of El/Ca especially at relatively low ratios, using a method on a Thermo Scientific iCAP Qc quadrupole Inductively Coupled Plasma Mass Spectrometer (ICP‐MS). We focus on two benthic foraminifera species, Hoeglundina elegans and Cibicidoides pachyderma, and prepared a suite of solution standards based on their typical El/Ca ranges to correct for signal drift and matrix effects during ICP‐MS analysis and to determine analytical precision. We observe comparable precisions with published studies at high El/Ca, and higher relative standard deviations for each element at lower El/Ca, as expected from counting statistics. The overall long‐term analytical precision (2σ) of the H. elegans‐like consistency standard solutions was 6.5%, 4.6%, 5.0%, for Li/Ca, Mg/Ca, Mg/Li, and 6.4%, 10.0%, 4.2% for B/Ca, Cd/Ca, Sr/Ca. The precision for H. elegans‐like Mg/Li is equivalent to a temperature uncertainty of 0.5–1.1°C. Measurement precisions were also assessed based on three international standards (one solution and two powder standards) and replicate measurements of H. elegans and C. pachyderma samples. We provide file templates and program scripts that can be used to design calibration and consistency standards, prepare run sequences, and convert the raw ICP‐MS data into molar ratios.
Identifying Recycled Materials Using Mo Isotopes in Intraplate Alkali Basalts From the Southeastern Margin of Tibetan Plateau
Authors: Xu Dongjing , Qi Yue , Wang Qiang , Li Jie , Wyman Derek A. , Kerr Andrew C. , Zhang Xiuzheng , Guo Peina 
Published: October 2024

AbstractMantle heterogeneity in lithology and geochemistry is often attributed to recycled subducted materials. While distinct mantle end‐members are identified by radiogenic isotopes, the specific recycled materials contributing to this heterogeneity remain debated. This study presents Mo‐Sr‐Nd‐Pb isotopic data for OIB‐like alkali basalts from the Maguan area in the southeastern Tibetan Plateau, focusing on slab inputs' role in mantle heterogeneity. The Miocene (ca. 13 Ma) Maguan alkali basalts are divided into two types based on petrographic and geochemical characteristics, showing similar Sr‐Nd‐Pb isotopic signatures but different Mo isotopic compositions. Type I basalts exhibit a wide δ98/95Mo range (−0.31‰ to −1.03‰, average −0.47‰ ± 0.06‰, 2SD = 0.40‰, n = 13), while type II basalts have heavy and constant δ98/95Mo values (−0.11‰ to −0.17‰, average −0.14‰ ± 0.01‰, 2SD = 0.05‰, n = 6). The unique low δ98/95Mo value (−1.03‰) in type I basalts is among the lowest reported in OIB‐like continental basalts. Type I basalts likely originate from an enriched asthenospheric mantle metasomatized by melts from recycled dehydrated oceanic crust and sediments, whereas type II basalts are derived from partial melting of an enriched asthenospheric mantle metasomatized by melts from recycled serpentinized peridotites. The residual Tethys oceanic slabs in the deep mantle significantly contribute to the mantle source of the Maguan basalts. The formation of Maguan Miocene magmas may be linked to mantle upwelling induced by the subduction of the West Burma plate. This study highlights the Mo isotopic system's utility in tracing complex slab fluxes generating mantle geochemical heterogeneity.
Interseismic Locking of the Xiaojiang Fault May Be Controlled by Pore Fluid Pressure
Authors: Zhu Yage , Diao Faqi , Wang Rongjiang , Shao Zhigang , Xiong Xiong 
Published: October 2024

AbstractAlthough fault locking state has been widely acquired with space geodetic observations, the mechanisms controlling fault locking are poorly known. Here, we infer the locking state of the Xiaojiang fault with a viscoelastic deformation model and integrated GNSS data, based on which we probe the mechanism that may control the locking pattern of the fault. Our results reveal four highly locked asperities along the Xiaojiang fault, which are separated by weak locking zones. Relying on the inferred locking degree and spring water temperature along the fault, we construct a model to connect the fault hydraulic conductivity with the cooling process of upwelling water. Model results suggest that high spring water temperature correlates with high hydraulic conductivity. Further, we use an experimental law to infer that the obtained high hydraulic conductivity may associate with high pore fluid pressure, which in turn weakens the fault frictional strength and leads to weak locking.
Inhomogeneous Sea‐Salt Aerosols—A New Strengthening Mechanism for the Western North Pacific Subtropical High
Authors: Gu Jiabei , Shu Shoujuan , Bi Lei , Li Wenjuan 
Published: October 2024

AbstractThe western North Pacific Subtropical High (WNPSH) significantly influences East Asian weather. In the Northwest Pacific where sea‐salt aerosols (SSAs) are abundant and the large‐scale environment is dominated by the dry subsidence of the WNPSH during summer, inhomogeneous SSAs form as a product of the environment. However, the extent to which inhomogeneous SSAs affect the WNPSH remains unclear. This study investigates the radiative effects of SSAs through numerical simulations, revealing a novel mechanism for the strengthening of the WNPSH. The results demonstrate that inhomogeneous SSAs enhance the WNPSH by generating diabatic cooling in the upper troposphere and associated unstable subsidence motion. Further considering the radiative hysteresis effects of inhomogeneous SSAs, the WNPSH further strengthens under the combined dynamic and thermodynamic influences associated with upper‐level radiative cooling. Inhomogeneous SSAs not only enhance the WNPSH but also influence the location where the central area of high pressure intensifies.
X‐Raying Neutral Density Disturbances in the Mesosphere and Lower Thermosphere Induced by the 2022 Hunga‐Tonga Volcano Eruption‐Explosion
Authors: Katsuda Satoru , Shinagawa Hiroyuki , Fujiwara Hitoshi , Jin Hidekatsu , Miyoshi Yasunobu , Miyoshi Yoshizumi , Motizuki Yuko , Nakajima Motoki , Nakazawa Kazuhiro , Nobukawa Kumiko K. , Otsuka Yuichi , Shinbori Atsushi , Sori Takuya , Tao Chihiro , Tashiro Makoto S. , Wada Yuuki , Yamawaki Takaya 
Published: October 2024

AbstractWe present X‐ray observations of the upper atmospheric density disturbance caused by the explosive eruption of the Hunga Tonga‐Hunga Ha'apai (HTHH) volcano on 15 January 2022. From 14 January to 16 January, the Chinese X‐ray astronomy satellite, Insight‐HXMT, was observing the supernova remnant Cassiopeia A. The X‐ray data obtained during Earth's atmospheric occultations allowed us to measure neutral densities in the altitude range of 90–150 km. The density profiles above 110 km altitude obtained before the major eruption are in reasonable agreement with expectations by both GAIA and NRLMSIS 2.0 models. In contrast, after the HTHH eruption, a severe density depletion was found up to 1,000 km away from the epicenter, and a relatively weak depletion extending up to km for over 8 hr after the eruption. In addition, density profiles showed wavy structures with a typical length scale of either 20 km (vertical) or 1,000 km (horizontal). This may be caused by Lamb waves or gravity waves triggered by the volcanic eruption.
Statistical Characteristics of Wavelike Banded Convection Associated With Ducted Gravity Waves Over Southern China
Authors: Zhou Xuan , Du Yu , Wei Junhong , Chen Zijian , Yang Hongpei 
Published: October 2024

AbstractWavelike banded convection occurs frequently and persistently in southern China, significantly impacting local weather. This study presents the first multi‐year investigation of wavelike banded convection associated with ducted gravity waves in southern China from 2013 to 2021 using radar mosaic maps. These convective bands are highly dependent on the wave ducting environment, which typically exhibits a three‐layer stratification structure. Out of 112 identified cases, two types were further classified based on the presence of a wave ducting vertical structure in the soundings: WaveDuct and nonWaveDuct type. Unlike nonWaveDuct type, the WaveDuct type predominantly happens on winter or spring nights. The phase speeds of WaveDuct convective bands also show a highly positive correlation with the depth of the ducting layer, consistent with wave ducting theory. This study provides a climatological understanding of the frequencies, movements, and environment conditions of wavelike banded convection related to ducted gravity waves over southern China.
Back‐Propagating Rupture: Nature, Excitation, and Implications
Authors: Ding Xiaotian , Xu Shiqing , Fukuyama Eiichi , Yamashita Futoshi 
Published: October 2024

AbstractRecent observations show that certain rupture phase can propagate backward relative to the earlier one during a single earthquake event. Such back‐propagating rupture (BPR) was not well considered by the conventional earthquake source studies and remains a mystery to the seismological community. Here we present a comprehensive analysis of BPR, by combining theoretical considerations, numerical simulations, and observational evidences. First, we argue that BPR in terms of back‐propagating stress wave is an intrinsic feature during dynamic ruptures; however, its signature can be easily masked by the destructive interference behind the primary rupture front. Then, we propose an idea that perturbation to an otherwise smooth rupture process may make some phases of BPR observable. We test and verify this idea by numerically simulating rupture propagation under a variety of perturbations, including a sudden change of stress, bulk or interfacial property and fault geometry along rupture propagation path. We further cross‐validate the numerical results by available observations from laboratory and natural earthquakes, and confirm that rupture “reflection” at free surface, rupture coalescence and breakage of prominent asperity are very efficient for exciting observable BPR. Based on the simulated and observed results, we classify BPR into two general types: interface wave and high‐order re‐rupture, depending on the stress recovery and drop before and after the arrival of BPR, respectively. Our work clarifies the nature and excitation of BPR, and can help improve the understanding of earthquake physics, the inference of fault property distribution and evolution, and the assessment of earthquake hazard.
Stochastic Analysis of Epithelial/Absorbed Power Density in Multilayered Planar Skin Model With Uncertain Tissue Electric Properties
Authors: Šušnjara Nejašmić Anna , Poljak Dragan 
Published: October 2024

AbstractStochastic analysis of the absorbed power density (APD) on skin surface exposed to radiation of halfwave dipole at 10, 30 and 90 GHz and for different antenna‐body distances is presented. Skin tissue is modeled as a half‐space consisting of one layer (skin) or three layers (skin, fat and muscle) whose permittivities and conductivities are uncertain. Deterministic part is based on numerical solution of Pocklington equation via Galerkin Bubnov Indirect Boundary Element method (GB‐IBEM) and numerical integration of the corresponding field integrals. Uncertainty from tissue electric parameters is propagated to APD via non‐intrusive Stochastic Collocation method (SCM) in order to compute stochastic moments of APD. For 1‐layered model APD stochastic moments are computed with 3 deterministic simulations. On the other hand APD mean and variance for 3 layered model are successfully computed with 13 deterministic simulations while skewness and kurtosis require 85 deterministic simulations. The ratio of APD standard deviation and mean decreases with frequency thus indicating that the uncertainty in the tissue electric properties has smaller effect on APD uncertainty at higher frequencies. Finally, sensitivity analysis carried out for both 1‐layered and 3‐layered models indicates the same conclusions. At 10 GHz skin permittivity and conductivity are the two most important parameters. However, as frequency increases the impact of skin conductivity prevails. This indicates that in frequency range 10–90 GHz the APD uncertainty quantification and sensitivity analysis can be carried out by using only 2‐dimensional stochastic model.
Channel Estimation for Deep Space Communications Under the Effect of Solar Scintillation
Authors: Xu Guanjun , Cai Lianning , Li Xianqiang , Shao Yanli , Song Zhaohui 
Published: October 2024

AbstractDuring probe‐to‐Earth superior conjunction, deep space communication channels will suffer from solar scintillation, leading to amplitude attenuation of received signals. This study aims to obtain the channel state information (CSI) on deep space channels affected by solar scintillation. Classical least squares (LS) and minimum mean squared error (MMSE) methods are adopted to perform channel estimation and compensate for the channel fading. Simulation results indicate that under the effect of solar scintillation, performing channel estimation technology can significantly improve bit error rate (BER) performance compared to systems without CSI, and the MMSE algorithm outperforms the LS for both BER and normalized mean squared error (NMSE). In addition, we also find that pilot density, geometric parameters, and the outer scale of solar wind turbulence has great influence on the estimation performance.
Active Fault Interaction in the Eastern Betic Cordillera: A Model of Coseismic and Postseismic Stress Transfer Following Historical Earthquakes in SE Spain
Authors: Yazdi Pouye , García‐Mayordomo Julián 
Published: October 2024

AbstractThe Spanish historical earthquake catalog reveals a significant number of destructive earthquakes (Mw 6.0) that have occurred along the Eastern Betic Shear Zone (EBSZ), a major active fault system at the Eastern Betic Cordillera. However, during the last century, seismic activity in this region has been characterized by the absence of large‐magnitude events, complicating yet underlining the importance of understanding active fault interaction in the EBSZ. In this work, we focus on the northeastern half of the EBSZ and apply a similar method to Yazdi et al. (2023, https://doi.org/10.1029/2023tc007917). We model a series of consecutive earthquakes ( VII; Mw 5.0) between the and centuries occurring along the Alhama de Murcia, Carrascoy and Bajo Segura faults, and assess their coseismic impact as well as explore the evolution of Coulomb stress changes due to the postseismic viscoelastic relaxation on the surrounding faults. Our results support a stress‐triggering connection between subsequent events and shed light on identifying the responsible faults for some. Our findings indicate that 1673 Mw 6.0 Orihuela and 1674 Mw 6.2 Lorca earthquakes, seemingly unrelated, could have both contributed to the forthcoming Mw 5.0 earthquake clustering along the Carrascoy fault. We show that attributing the 1829 Mw 6.6 Torrevieja earthquake to the Bajo Segura fault better describes the occurrence of earthquake sequences between the mid‐ and early centuries. Finally, we propose the Alhama de Murcia and the Carrascoy faults as responsible initiators for the early ‐century earthquake sequence in the Segura Medio valley. These findings provide valuable insights for seismic hazard modeling in the region.