Earth and Space Science最新文献

{"title":"Tsunami Data Assimilation Using High-Frequency Radar-Derived Surface Currents by Considering Beam Angle-Dependent Measurement Error Distributions","authors":"Muhammad Irham Sahana,&nbsp;Ryotaro Fuji,&nbsp;Tomoyuki Takahashi,&nbsp;Hirofumi Hinata","doi":"10.1029/2024EA003561","DOIUrl":"https://doi.org/10.1029/2024EA003561","url":null,"abstract":"<p>The application of high-frequency radar as an instrument for assimilating tsunami-induced current fields is garnering increasing interest. The performance of surface current velocity measurements depends on the azimuthal differences between the crossing radar beams at the measurement points. This study aimed to incorporate the measurement error distributions of the east-west and north-south velocity components into tsunami data assimilation based on an optimal interpolation method, assuming Gaussian noise with the time-invariant and a uniform standard deviation (STD = 5 cm/s) of radial velocity measurements. Through the empirical orthogonal function (EOF) analysis of radar-derived surface currents in the Kii Channel, Japan, the velocities reconstructed using higher modes (EOFs 16–274) were associated with measurement errors, portraying nonuniform distribution depending on the crossing beam angle of two radar beams. Based on independent fifteen-time assimilation experiments for two different tsunami scenarios, for a uniform water depth of 500 m, we observed a significant improvement of up to 29% and 0.9% in the assimilation performance (on average) over the along-coast stations for scenarios with 1- and 5-m maximum initial sea surface heights, respectively. The measurement errors dependent on the crossing beam angle reduced the error-induced tsunamis, resulting in stable assimilations, with lower STDs in the fifteen-time assimilation performances. When the STD of Gaussian noise varies with time, it is important to consider the temporal change in the radial velocity measurement errors and/or noise-filtering techniques, to maintain a certain level of noise intensity.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA003561","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observed Correlation Between Local Topography and Passive Neutron Measurements From the Dynamic Albedo of Neutrons (DAN) Instrument on the Mars Science Laboratory (MSL) Rover","authors":"Steven D. Dibb,&nbsp;Craig Hardgrove,&nbsp;Jack Lightholder,&nbsp;Lena Heffern,&nbsp;Bent Ehresmann","doi":"10.1029/2023EA003130","DOIUrl":"https://doi.org/10.1029/2023EA003130","url":null,"abstract":"<p>The Dynamic Albedo of Neutrons (DAN) instrument on the Mars Science Laboratory Curiosity rover primarily measures neutrons that have undergone interactions with rocks and materials in the rover's local environment. As the rover ascends Aeolis Mons, it may encounter more extreme local topography (e.g., cliffs, gullies, canyons). We present three parts of the rover's traverse in which local topography, expressed as the average local relief relative to the rover, is moderately to strongly correlated with an increase in passive thermal neutron count rates. These increases in count rates are consistent with results from radiation transport models of the instrument's performance near simulated topographic features. Additional DAN measurements in areas of high average local relief (&gt;0.25 m) within 5 m of the instrument could bolster this correlation. DAN's sensitivity to topography in its passive mode could be utilized as a new measurement capability and has implications for the operation of future landed missions carrying neutron spectrometers (e.g., VIPER, MoonRanger, Lunar-VISE).</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023EA003130","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep-Focus Earthquake Mechanisms at the Subducting Nazca Plate (Peru-Brazil Border): Cold Slab Behavior in a Warm Plate","authors":"G. S. Leite Neto,&nbsp;J. Julià,&nbsp;G. A. Prieto","doi":"10.1029/2024EA003617","DOIUrl":"https://doi.org/10.1029/2024EA003617","url":null,"abstract":"<p>We calculate focal mechanisms and centroid depths for deep-focus earthquakes (DFEs) along the Peru-Brazil border. We obtained a total of 28 focal solutions for events with magnitudes between 4.2 and 7.5 Mw and occurring between 2014 and 2022. Focal mechanisms indicate predominance of normal faulting, demonstrating a rather uniform down-dip compression (DDC) regime within the plate. The orientations of the nodal planes suggest that earthquakes tend to occur along faults parallel to the local slab strike, although other fault types are documented. Stress orientations derived from the focal mechanisms agree with patterns expected if faulting were initiated by transformational faulting on a metastable olivine wedge (MOW) under DDC. Centroid depths range between 557 and 659 km, defining a narrow seismic zone within the lower portion of the subducting plate and an aseismic upper portion. We suggest that DFEs nucleate through transformational faulting within a narrow MOW preserved at a colder slab segment right above the lower mantle and juxtaposed to a shallower, warmer segment at around 500 km depth. This thermal complexity was possibly produced through flat subduction initiated by the subduction of the Nazca Ridge. We speculate that subduction of other aseismic ridges is possibly controlling the thermal state of the Nazca slab as a whole and, consequently, the depth distribution of DFEs along the South America subduction front.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA003617","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry by Laser-Induced Breakdown Spectroscopy on the Moon: Accuracy, Detection Limits, and Realistic Constraints on Interpretations","authors":"M. D. Dyar,&nbsp;C. R. Ytsma,&nbsp;K. Lepore","doi":"10.1029/2024EA003635","DOIUrl":"https://doi.org/10.1029/2024EA003635","url":null,"abstract":"<p>After its successful implementation on the surface of Mars, laser-induced breakdown spectroscopy (LIBS) is likely to be employed on a diverse array of other solid bodies in our Solar System. Here we address the accuracy and quantification limits of LIBS under the vacuum conditions found on the Moon relative to what is known about its geochemistry. The interplay among accuracy as represented by root mean-squared errors (RMSE), the median concentration, and quantification limits (LOQ) of LIBS analyses for each of 69 elements is evaluated. This comparison shows that several key elements in lunar geochemistry cannot be well-studied with LIBS, including K₂O, S, Rb, Br, and C. Conversely, highly accurate analyses of SiO₂, CaO, and many minor and trace elements such as Mn, Yb, and Zn are possible under conditions found on the Moon. Use of LIBS must always be considered in the context of the geochemistry and geology of the target materials.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA003635","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Deep Learning Approach for Automatic Ionogram Parameters Recognition With Convolutional Neural Networks","authors":"Ruslan Sherstyukov,&nbsp;Samson Moges,&nbsp;Alexander Kozlovsky,&nbsp;Thomas Ulich","doi":"10.1029/2023EA003446","DOIUrl":"https://doi.org/10.1029/2023EA003446","url":null,"abstract":"<p>Typical ionosondes operate with &gt;5 min time intervals, which is enough to obtain regular parameters of the ionosphere, but insufficient to observe short-term processes in the Earth's ionosphere. The key point for this study is to increase the ionosondes data time resolution by automatization of ionogram scaling routine. In this study we show the results of implementation of deep learning approach for ionogram parameters scaling. We trained the model on 13 years ionogram data set of Sodankyla ionosonde at high latitude region (67°N). We tested our autoscaling program tool on 2021 years data set and evaluate errors between operator and automatic parameters scaling. The root mean square errors for critical frequencies <i>foF2</i>, <i>foF1</i>, <i>foE</i>, <i>foEs, fmin, fbEs</i> and virtual heights <i>h′F, h′E, h′Es</i> are estimated as 0.12 MHz (2 pixels), 0.07 MHz (1.16 pixels), 0.15 MHz (2.5 pixels), 0.33 MHz (5.5 pixels), 0.15 MHz (2.5 pixels), 0.17 MHz (2.83 pixels), 7.7 km (1.34 pixels), 7.0 km (1.22 pixels), 7.1 km (1.24 pixels), respectively.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023EA003446","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic Utilization of Spaceborne SAR Observations for Monitoring the Baltic Sea Flow Through the Danish Straits","authors":"Anis Elyouncha,&nbsp;Göran Broström,&nbsp;Harald Johnsen","doi":"10.1029/2024EA003794","DOIUrl":"https://doi.org/10.1029/2024EA003794","url":null,"abstract":"<p>Synthetic aperture radar (SAR) has emerged as a key instrument in oceanography due to its high spatial resolution and sensitivity to ocean surface dynamics. The main limitation of a single spaceborne SAR is the long repeat cycle (e.g., 12 days for Sentinel-1), which hinders its capability to monitor the temporal evolution of oceanic processes. The principal objective of this study is to demonstrate the potential of spaceborne SAR to monitor the temporal variation of ocean surface circulation. This is assessed using the Baltic Sea flow through the Danish strait Fehmarn Belt as a case study. In order to overcome the temporal sampling limitation, data from three satellites are combined, namely Sentinel-1A, Sentinel-1B and TanDEM-X. The average revisit time achieved by combining the three satellites is 1.2 days. Two months of opportunistic SAR data (June and July 2020) covering the Fehmarn Belt are used. The radial surface current derived from SAR is compared to ocean model and in situ data. It is shown that the dominant processes that govern the circulation in the Fehmarn Belt exhibit time scales larger than 2 days. Subsequently, it is demonstrated that SAR effectively captures the synoptic-scale features (time scales larger than 2 days) of the Baltic Sea circulation, thereby enabling monitoring the temporal variations of flow dynamics. Comparison of the SAR-derived radial surface current against in situ measurements yields comparable bias (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≤</mo>\u0000 </mrow>\u0000 <annotation> ${le} $</annotation>\u0000 </semantics></math>0.08 m/s) and correlation coefficient (R <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>≈</mo>\u0000 </mrow>\u0000 <annotation> ${approx} $</annotation>\u0000 </semantics></math> 0.75) but lower standard deviations and rms errors (0.15 m/s) than those exhibited by the ocean model (0.31 m/s).</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 10","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA003794","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generalized Time-Series Analysis for In Situ Spacecraft Observations: Anomaly Detection and Data Prioritization Using Principal Components Analysis and Unsupervised Clustering","authors":"Matthew G. Finley,&nbsp;Miguel Martinez-Ledesma,&nbsp;William R. Paterson,&nbsp;Matthew R. Argall,&nbsp;David M. Miles,&nbsp;John C. Dorelli,&nbsp;Eftyhia Zesta","doi":"10.1029/2024EA003753","DOIUrl":"https://doi.org/10.1029/2024EA003753","url":null,"abstract":"<p>In situ spacecraft observations are critical to our study and understanding of the various phenomena that couple mass, momentum, and energy throughout near-Earth space and beyond. However, on-orbit telemetry constraints can severely limit the capability of spacecraft to transmit high-cadence data, and missions are often only able to telemeter a small percentage of their captured data at full rate. This presents a programmatic need to prioritize intervals with the highest probability of enabling the mission's science goals. Larger missions such as the Magnetospheric Multiscale mission (MMS) aim to solve this problem with a Scientist-In-The-Loop (SITL), where a domain expert flags intervals of time with potentially interesting data for high-cadence data downlink and subsequent study. Although suitable for some missions, the SITL solution is not always feasible, especially for low-cost missions such as CubeSats and NanoSats. This manuscript presents a generalizable method for the detection of anomalous data points in spacecraft observations, enabling rapid data prioritization without substantial computational overhead or the need for additional infrastructure on the ground. Specifically, Principal Components Analysis and One-Class Support Vector Machines are used to generate an alternative representation of the data and provide an indication, for each point, of the data's potential for scientific utility. The technique's performance and generalizability is demonstrated through application to intervals of observations, including magnetic field data and plasma moments, from the CASSIOPE e-POP/Swarm-Echo and MMS missions.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA003753","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Analog Modeling Materials on Topographic Photogrammetry (SfM) Reconstructions","authors":"Adam J. Cawood,&nbsp;Danielle Y. Wyrick","doi":"10.1029/2024EA003607","DOIUrl":"https://doi.org/10.1029/2024EA003607","url":null,"abstract":"<p>Accurate topographic data are essential for quantitative structural analysis, both in natural settings and in the laboratory. The selection of modeling materials (with appropriate rheological properties) is known to be fundamental for the success of scaled physical analog experiments. However, the optical properties of analog materials and their impact on the reliability and precision of high-resolution topographic reconstructions have not (to our knowledge) previously been assessed. Here we evaluate the effects of material composition, color, and grain size on Structure-from-Motion (SfM) photogrammetry reconstruction efficacy for deformed and undeformed model configurations in the laboratory. Image collections for photogrammetry are acquired from multiple camera positions with a handheld digital camera, and reconstructions are registered using ground control points in a local coordinate system. Static experiments show that low reflectivity granular materials (e.g., silica sand, volcanic ash, pumice, and Al₂O₃) yield relatively reliable photogrammetry data for a wide range of grain sizes (44–2,400 μm) but larger grain sizes (≥250 μm) provide more robust results. Reflective materials (e.g., glass beads, wet clay) yield less reliable point-clouds but the addition of low-reflectivity granular materials (e.g., Al₂O₃ grains) on the surface of wet clay improves reconstruction results, with higher grain densities typically yielding lower point-cloud residuals. SfM-photogrammetry reconstruction of deformed clay analog models tends to improve at higher extension magnitudes because of fault and associated texture development on model surfaces. We anticipate that our results will help practitioners to improve the precision and reliability of photogrammetric data acquired in the analog modeling laboratory.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA003607","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Database for Simultaneous Observations of the Earth's Magnetosheath by Cluster and MMS Between 2017 and 2021","authors":"Costel Munteanu,&nbsp;Eliza Teodorescu,&nbsp;Marius Echim,&nbsp;Daniel Dumitru,&nbsp;Gabriel Voitcu,&nbsp;Maximilian Teodorescu,&nbsp;Cătălin Negrea","doi":"10.1029/2024EA003638","DOIUrl":"https://doi.org/10.1029/2024EA003638","url":null,"abstract":"<p>This paper describes a catalog of simultaneous observations of the Earth's magnetosheath by ESA's Cluster and NASA's MMS missions. The catalog is built from a visual inspection of summary plots provided by the two missions complemented by an analysis of high-resolution magnetic field data. The catalog includes 117 events when Cluster 4 and MMS 4 crossed simultaneously the magnetosheath between January–April, 2017–2021. The dynamical and turbulent features of the magnetosheath are strongly influenced by <i>θ</i>_<i>Bn</i>, the angle between the interplanetary magnetic field (IMF) and the shock normal direction. To facilitate such investigations, we also determine the bow shock geometry for each event based on two different approaches: (a) a minimum variance analysis of in-situ magnetic field measurements, and (b) a geometrical approach which considers a bow shock model parameterized by OMNI data. A description of spacecraft trajectory during each event is also provided. Additional data describe the relative distances between Cluster 4 and MMS 4, a classification of each event as either quasi-parallel or quasi-perpendicular, and the distribution of events per magnetospheric flank. The time intervals for the Cluster - MMS conjunctions are included in the catalog, as well as all associated figures and tables discussed in this paper are made available through an independent online data repository, and can be freely downloaded and used by any interested researcher.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA003638","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid-Driven Seismicity in the Baihetan Reservoir Area Revealed by 3D Seismic Tomography Based on Dense Seismic Arrays","authors":"Mengqiao Duan,&nbsp;Lianqing Zhou,&nbsp;Cuiping Zhao,&nbsp;Xiaodong Zhang","doi":"10.1029/2023EA003397","DOIUrl":"https://doi.org/10.1029/2023EA003397","url":null,"abstract":"<p>After impounding the Baihetan Water Reservoir in a historically seismically active area, numerous earthquakes occurred, but it is uncertain if they are connected to the impoundment. Based on the dense seismic network, this study used local earthquake tomography to construct high-resolution <i>V</i>_P (<i>P</i>-wave velocity) and <i>V</i>_P/<i>V</i>_S models (<i>P</i>- to <i>S</i>-wave velocity ratio) and update earthquake locations after the impoundment of Baihetan reservoir. Our study revealed that the reservoir water spreads from the dam site to the Qiaojia Basin and the Heishuihe branch, and pore pressure diffusion along faults induces many earthquakes. Reservoir water migrates through hidden faults and fractures beneath Hulukou, spreading to both sides and saturating some rocks below 7 km beneath the dam site-Lianhuatang section, causing multiple magnitude 3.5+ earthquakes. This study reveals that reservoir water migration drives earthquakes in the reservoir area, offering new insights into seismogenesis following the Baihetan reservoir's impoundment, potentially applicable to understanding reservoir-induced earthquakes in other reservoirs.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"11 9","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023EA003397","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}