arXiv - PHYS - Geophysics最新文献_第3页

Urban Sensing Using Existing Fiber-Optic Networks 利用现有光纤网络进行城市传感

arXiv - PHYS - Geophysics Pub Date : 2024-09-09 DOI: arxiv-2409.05820

Jingxiao Liu, Haipeng Li, Hae Young Noh, Paolo Santi, Biondo Biondi, Carlo Ratti

{"title":"Urban Sensing Using Existing Fiber-Optic Networks","authors":"Jingxiao Liu, Haipeng Li, Hae Young Noh, Paolo Santi, Biondo Biondi, Carlo Ratti","doi":"arxiv-2409.05820","DOIUrl":"https://doi.org/arxiv-2409.05820","url":null,"abstract":"The analysis of urban seismic sources offers valuable insights into urban\u0000environments, including seismic hazards, infrastructure conditions, human\u0000mobility, and cultural life. Yet, accurate detection and localization of\u0000seismic sources at the urban scale with conventional seismic sensing networks\u0000is unavailable due to the prohibitive costs of ultra-dense seismic arrays\u0000required for imaging high-frequency anthropogenic seismic sources. Here, we\u0000leverage existing fiber-optic networks as a distributed acoustic sensing system\u0000to accurately locate urban seismic sources and estimate how their intensity\u0000varies with time. By repurposing a 50-kilometer telecommunication fiber into an\u0000ultra-dense seismic array with 50,000 channels, we generate high-resolution\u0000spatiotemporal maps of seismic source power (SSP) across San Jose, California.\u0000Our approach overcomes the proximity limitations of urban seismic sensing,\u0000enabling accurate localization of remote seismic sources generated by urban\u0000activities. Examples of detected activities are vehicle movements and\u0000operations at construction sites and schools. We also show strong correlations\u0000between SSP values and noise level measurements, as well as various persistent\u0000urban features, including point of interest density, land use patterns, and\u0000demographics. Our study shows how spatiotemporal SSP maps can be turned into\u0000novel urban data that effectively captures urban dynamics across multiple\u0000features, thus opening the way towards the use of fiber-optic networks as a\u0000ubiquitous and general-purpose urban sensing platform, with wide-ranging\u0000applications in urban and environmental studies.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Vortex structures under dimples and scars in turbulent free-surface flows 自由表面湍流中凹陷和疤痕下的涡旋结构

arXiv - PHYS - Geophysics Pub Date : 2024-09-09 DOI: arxiv-2409.05409

Jørgen R. Aarnes, Omer Babiker, Anqing Xuan, Lian Shen, Simen Å. Ellingsen

{"title":"Vortex structures under dimples and scars in turbulent free-surface flows","authors":"Jørgen R. Aarnes, Omer Babiker, Anqing Xuan, Lian Shen, Simen Å. Ellingsen","doi":"arxiv-2409.05409","DOIUrl":"https://doi.org/arxiv-2409.05409","url":null,"abstract":"Turbulence beneath a free surface leaves characteristic long-lived signatures\u0000on the surface, such as upwelling 'boils', near-circular 'dimples' and\u0000elongated 'scars', easily identifiable by eye, e.g., in riverine flows. In this\u0000paper, we use Direct Numerical Simulations to explore the connection between\u0000these surface signatures and the underlying vortical structures. We investigate\u0000dimples, known to be imprints of surface-attached vortices, and scars, which\u0000have yet to be extensively studied, by analysing the conditional probabilities\u0000that a point beneath a signature is within a vortex core as well as the\u0000inclination angles of sub-signature vorticity. The analysis shows that the\u0000likelihood of vortex presence beneath a dimple decreases from the surface down\u0000through the viscous and blockage layers in a near-Gaussian manner, influenced\u0000by the dimple's size and the bulk turbulence. When expressed as a function of\u0000depth over the Taylor microscale $lambda_T$, this probability is independent\u0000of Reynolds and Weber number. Conversely, the probability of finding a vortex\u0000beneath a scar increases sharply from the surface to a peak at the edge of the\u0000viscous layer, at a depth of approximately $lambda_T/4$. Distributions of\u0000vortical orientation also show a clear pattern: a strong preference for\u0000vertical alignment below dimples and an equally strong preference for\u0000horizontal alignment below scars. Our findings suggest that scars can be\u0000defined as imprints of horizontal vortices approximately a quarter of the\u0000Taylor microscale beneath the surface, analogous to how dimples can be defined\u0000as imprints of surface-attached vertical vortex tubes.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Seismic monitoring of CO2 plume dynamics using ensemble Kalman filtering 利用集合卡尔曼滤波对二氧化碳羽流动态进行地震监测

arXiv - PHYS - Geophysics Pub Date : 2024-09-08 DOI: arxiv-2409.05193

Grant Bruer, Abhinav Prakash Gahlot, Edmond Chow, Felix Herrmann

引用次数: 0

Seven decades of exploring planetary interiors with rotating convection experiments 用旋转对流实验探索行星内部七十年

arXiv - PHYS - Geophysics Pub Date : 2024-09-08 DOI: arxiv-2409.05220

Alban Pothérat, Susanne Horn

{"title":"Seven decades of exploring planetary interiors with rotating convection experiments","authors":"Alban Pothérat, Susanne Horn","doi":"arxiv-2409.05220","DOIUrl":"https://doi.org/arxiv-2409.05220","url":null,"abstract":"The interiors of many planets consist mostly of fluid layers. When these\u0000layers are subject to superadiabatic temperature or compositional gradients,\u0000turbulent convection transports heat and momentum. In addition, planets are\u0000fast rotators. Thus, the key process that underpins planetary evolution, the\u0000dynamo action, flow patterns and more, is rotating convection. Because\u0000planetary interiors are inaccessible to direct observation, experiments offer\u0000physically consistent models that are crucial to guide our understanding. If we\u0000can fully understand the laboratory model, we may eventually fully understand\u0000the original. Experimentally reproducing rotating thermal convection relevant\u0000to planetary interiors comes with specific challenges, e.g. modelling the\u0000central gravity field of a planet that is parallel to the temperature gradient.\u0000Three classes of experiments tackle this challenge. One approach consists of\u0000using an alternative central force field, such as the electric force. These\u0000are, however, weaker than gravity and require going to space. Another method\u0000entails rotating the device fast enough so that the centrifugal force\u0000supersedes Earth's gravity. This mimics the equatorial regions of a planet.\u0000Lastly, by using the actual lab gravity aligned with the rotation axis, insight\u0000into the polar regions is gained. These experiments have been continuously\u0000refined during the past seven decades. We review their evolution, from the\u0000early days of visualising the onset patterns of convection, over central force\u0000field experiments in spacecrafts, liquid metal experiments, to the latest\u0000optical velocity mapping of rotating magnetoconvection in sulfuric acid inside\u0000high-field magnets. We show how innovative experimental design and emerging\u0000experimental techniques advanced our understanding and painted a more realistic\u0000picture of planetary interiors, including Earth's liquid metal outer core.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Online learning of eddy-viscosity and backscattering closures for geophysical turbulence using ensemble Kalman inversion 利用集合卡尔曼反演在线学习地球物理湍流的涡粘度和反向散射闭合度

arXiv - PHYS - Geophysics Pub Date : 2024-09-08 DOI: arxiv-2409.04985

Yifei Guan, Pedram Hassanzadeh, Tapio Schneider, Oliver Dunbar, Daniel Zhengyu Huang, Jinlong Wu, Ignacio Lopez-Gomez

{"title":"Online learning of eddy-viscosity and backscattering closures for geophysical turbulence using ensemble Kalman inversion","authors":"Yifei Guan, Pedram Hassanzadeh, Tapio Schneider, Oliver Dunbar, Daniel Zhengyu Huang, Jinlong Wu, Ignacio Lopez-Gomez","doi":"arxiv-2409.04985","DOIUrl":"https://doi.org/arxiv-2409.04985","url":null,"abstract":"Different approaches to using data-driven methods for subgrid-scale closure\u0000modeling have emerged recently. Most of these approaches are data-hungry, and\u0000lack interpretability and out-of-distribution generalizability. Here, we use\u0000{online} learning to address parametric uncertainty of well-known physics-based\u0000large-eddy simulation (LES) closures: the Smagorinsky (Smag) and Leith\u0000eddy-viscosity models (1 free parameter) and the Jansen-Held (JH)\u0000backscattering model (2 free parameters). For 8 cases of 2D geophysical\u0000turbulence, optimal parameters are estimated, using ensemble Kalman inversion\u0000(EKI), such that for each case, the LES' energy spectrum matches that of direct\u0000numerical simulation (DNS). Only a small training dataset is needed to\u0000calculate the DNS spectra (i.e., the approach is {data-efficient}). We find the\u0000optimized parameter(s) of each closure to be constant across broad flow regimes\u0000that differ in dominant length scales, eddy/jet structures, and dynamics,\u0000suggesting that these closures are {generalizable}. In a-posteriori tests based\u0000on the enstrophy spectra and probability density functions (PDFs) of vorticity,\u0000LES with optimized closures outperform the baselines (LES with standard Smag,\u0000dynamic Smag or Leith), particularly at the tails of the PDFs (extreme events).\u0000In a-priori tests, the optimized JH significantly outperforms the baselines and\u0000optimized Smag and Leith in terms of interscale enstrophy and energy transfers\u0000(still, optimized Smag noticeably outperforms standard Smag). The results show\u0000the promise of combining advances in physics-based modeling (e.g., JH) and\u0000data-driven modeling (e.g., {online} learning with EKI) to develop\u0000data-efficient frameworks for accurate, interpretable, and generalizable\u0000closures.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A foundation model enpowered by a multi-modal prompt engine for universal seismic geobody interpretation across surveys 由多模式提示引擎驱动的地基模型，用于跨勘探的通用地震地质体解释

arXiv - PHYS - Geophysics Pub Date : 2024-09-08 DOI: arxiv-2409.04962

Hang Gao, Xinming Wu, Luming Liang, Hanlin Sheng, Xu Si, Gao Hui, Yaxing Li

{"title":"A foundation model enpowered by a multi-modal prompt engine for universal seismic geobody interpretation across surveys","authors":"Hang Gao, Xinming Wu, Luming Liang, Hanlin Sheng, Xu Si, Gao Hui, Yaxing Li","doi":"arxiv-2409.04962","DOIUrl":"https://doi.org/arxiv-2409.04962","url":null,"abstract":"Seismic geobody interpretation is crucial for structural geology studies and\u0000various engineering applications. Existing deep learning methods show promise\u0000but lack support for multi-modal inputs and struggle to generalize to different\u0000geobody types or surveys. We introduce a promptable foundation model for\u0000interpreting any geobodies across seismic surveys. This model integrates a\u0000pre-trained vision foundation model (VFM) with a sophisticated multi-modal\u0000prompt engine. The VFM, pre-trained on massive natural images and fine-tuned on\u0000seismic data, provides robust feature extraction for cross-survey\u0000generalization. The prompt engine incorporates multi-modal prior information to\u0000iteratively refine geobody delineation. Extensive experiments demonstrate the\u0000model's superior accuracy, scalability from 2D to 3D, and generalizability to\u0000various geobody types, including those unseen during training. To our\u0000knowledge, this is the first highly scalable and versatile multi-modal\u0000foundation model capable of interpreting any geobodies across surveys while\u0000supporting real-time interactions. Our approach establishes a new paradigm for\u0000geoscientific data interpretation, with broad potential for transfer to other\u0000tasks.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Feasibility of keeping Mars warm with nanoparticles 用纳米粒子为火星保温的可行性

arXiv - PHYS - Geophysics Pub Date : 2024-09-05 DOI: arxiv-2409.03925

Samaneh Ansari, Edwin S. Kite, Ramses Ramirez, Liam J. Steele, Hooman Mohseni

引用次数: 0

Physics-informed Neural Networks with Fourier Features for Seismic Wavefield Simulation in Time-Domain Nonsmooth Complex Media 具有傅立叶特征的物理信息神经网络用于时域非光滑复杂介质中的地震波场模拟

arXiv - PHYS - Geophysics Pub Date : 2024-09-05 DOI: arxiv-2409.03536

Yi Ding, Su Chen, Hiroe Miyake, Xiaojun Li

{"title":"Physics-informed Neural Networks with Fourier Features for Seismic Wavefield Simulation in Time-Domain Nonsmooth Complex Media","authors":"Yi Ding, Su Chen, Hiroe Miyake, Xiaojun Li","doi":"arxiv-2409.03536","DOIUrl":"https://doi.org/arxiv-2409.03536","url":null,"abstract":"Physics-informed neural networks (PINNs) have great potential for flexibility\u0000and effectiveness in forward modeling and inversion of seismic waves. However,\u0000coordinate-based neural networks (NNs) commonly suffer from the \"spectral bias\"\u0000pathology, which greatly limits their ability to model high-frequency wave\u0000propagation in sharp and complex media. We propose a unified framework of\u0000Fourier feature physics-informed neural networks (FF-PINNs) for solving the\u0000time-domain wave equations. The proposed framework combines the stochastic\u0000gradient descent (SGD) strategy with a pre-trained wave velocity surrogate\u0000model to mitigate the singularity at the point source. The performance of the\u0000activation functions and gradient descent strategies are discussed through\u0000ablation experiments. In addition, we evaluate the accuracy comparison of\u0000Fourier feature mappings sampled from different families of distributions\u0000(Gaussian, Laplace, and uniform). The second-order paraxial approximation-based\u0000boundary conditions are incorporated into the loss function as a soft\u0000regularizer to eliminate spurious boundary reflections. Through the non-smooth\u0000Marmousi and Overthrust model cases, we emphasized the necessity of the\u0000absorbing boundary conditions (ABCs) constraints. The results of a series of\u0000numerical experiments demonstrate the accuracy and effectiveness of the\u0000proposed method for modeling high-frequency wave propagation in sharp and\u0000complex media.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Maximum size and magnitude of injection-induced slow slip events 注水引发的慢滑事件的最大规模和强度

arXiv - PHYS - Geophysics Pub Date : 2024-09-05 DOI: arxiv-2409.03330

Alexis Sáez, François Passelègue, Brice Lecampion

引用次数: 0

The role of energetic flow structures on the aeolian transport of sediment and plastic debris 能流结构对沉积物和塑料碎片风化迁移的作用

arXiv - PHYS - Geophysics Pub Date : 2024-09-05 DOI: arxiv-2409.03494

Manousos Valyrakis, Xiao Zhao, Thomas Pähtz, Zhen Li

{"title":"The role of energetic flow structures on the aeolian transport of sediment and plastic debris","authors":"Manousos Valyrakis, Xiao Zhao, Thomas Pähtz, Zhen Li","doi":"arxiv-2409.03494","DOIUrl":"https://doi.org/arxiv-2409.03494","url":null,"abstract":"Recently, significant progress has been made in conceptually describing the\u0000dynamic aspects of coarse particle entrainment, which has been explored\u0000experimentally for open channel flows. The aim of this study is to extend the\u0000application of energy criterion to the low mobility aeolian transport of solids\u0000(including both natural sediment and anthropogenic debris such as plastics),\u0000ranging from incomplete (rocking) to full (rolling) entrainments. This is\u0000achieved by linking particle movements to energetic flow events, which are\u0000defined as flow structures with the ability to work on particles, setting them\u0000into motion. It is hypothesized that such events should impart sufficient\u0000energy to the particles, above a certain threshold value. The concept's\u0000validity is demonstrated experimentally, using a wind tunnel and laser distance\u0000sensor (LDS) to capture the dynamics of an individual target particle, exposed\u0000on a rough bed surface. Measurements are acquired at a high spatiotemporal\u0000resolution, and synchronously with the instantaneous air velocity at an\u0000appropriate distance upwind of the target particle, using a hot film\u0000anemometer. This enables the association of flow events with rocking and\u0000rolling entrainments. Furthermore, it is shown that rocking and rolling may\u0000have distinct energy thresholds. Estimates of the energy transfer efficiency,\u0000normalized by the drag coefficient, range over an order of magnitude (from\u0000about 0.001 to 0.0048 for rocking, up to about 0.01, for incipient rolling).\u0000The proposed event-based theoretical framework is a novel approach to\u0000characterizing the energy imparted from the wind to the soil surface and could\u0000have potential implications for modelling intermittent creep transport of\u0000coarse particles and related aeolian bedforms.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0