Earth and Space Science最新文献

{"title":"Influence of Subduction Interface Geometry on Surface Displacements and Slip Processes in Cascadia","authors":"H. M. Elston,&nbsp;J. P. Loveless,&nbsp;J. R. Delph","doi":"10.1029/2025EA004623","DOIUrl":"https://doi.org/10.1029/2025EA004623","url":null,"abstract":"<p>The subduction interface geometry is particularly important for estimating interplate coupling and surface geodetic motion, which has significant implications for seismic hazard mapping. Several published Cascadia subduction interface geometries derived from different seismic data sets vary significantly from one another. However, results from deformation models that use the different interface geometries are rarely systematically compared. Here, we assess the impact of subduction interface geometry on surface motion predictions, slip inversion results, and interface coupling estimates from four published Cascadia subduction interface geometries. We isolate the effect of the interface geometry on the predicted surface motion by applying uniform unit slip or Gaussian slip patterns to each interface geometry and calculate the predicted displacements at locations of GNSS stations. The forward model-predicted horizontal displacements can differ by &gt;20% and show azimuthal differences up to 10°; such differences correlate spatially to geometric differences amongst the interface realizations. Inversions of surface displacements estimated using a Gaussian distribution of slip, mimicking an earthquake, recover the applied slip distribution with differing spatial patterns and residuals of up to 38% of the maximum applied slip. Block models that use the four interface realizations produce coupling estimates on the interface with regions of significant coupling (&gt;50%) that differ noticeably in down-dip extent and lateral continuity. The results we present suggest that models utilizing interface geometry as an input, such as earthquake and tsunami models, should consider comparing models with differing interface geometries to critically evaluate model uncertainty stemming from this fundamental input.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025EA004623","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145272604","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":"Implementation and Evaluation of Storm-Following 3DIAU for Hurricane Intensity Prediction Improvements in Operational HAFS","authors":"Xu Lu,&nbsp;Yonghui Weng,&nbsp;Bin Liu,&nbsp;Zhan Zhang,&nbsp;Xuguang Wang,&nbsp;Jing Cheng,&nbsp;Shun Liu,&nbsp;Daryl Kleist,&nbsp;Vijay Tallapragada","doi":"10.1029/2025EA004485","DOIUrl":"https://doi.org/10.1029/2025EA004485","url":null,"abstract":"<p>Accurate hurricane intensity prediction remains a critical challenge in numerical weather prediction (NWP). This study implements and evaluates a newly developed Storm-Following Three-Dimensional Incremental Analysis Update (3DIAU) methodology for high-resolution regional hurricane models with storm-following nest capabilities. Built upon the feature-relative 4DIAU approach proposed by Lu and Wang (2021), https://doi.org/10.1175/MWR-D-21-0068.1, the method gradually introduces Data Assimilation (DA) increments relative to the storm's position, reducing spin-up imbalances and improving intensity predictions. Retrospective experiments were conducted over three Atlantic hurricane seasons (2021–2023) using the 2024 operational Hurricane Analysis and Forecast System (HAFS) version 2.0A configuration. Sensitivity experiments suggest that increment weighting should depend on storm strength. The storm-strength-dependent configuration yields an average improvement of 3% in intensity prediction skill, with modest gains in long-term track predictions. A case study further demonstrates that gradual, storm-relative adjustments mitigate disruptions caused by intermittent DA and enhance forecast performance. The Storm-Following 3DIAU will be incorporated into the 2025 operational HAFS V2.1 upgrade.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025EA004485","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145272605","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":"Outbreak of Gigantic Jets Over an Isolated Thunderstorm in South China","authors":"Yiwei Zhao,&nbsp;Gaopeng Lu,&nbsp;Hailiang Huang,&nbsp;Jixin Wang,&nbsp;Feifan Liu,&nbsp;Zhengwei Cheng,&nbsp;Renjun Zhou,&nbsp;Yazhou Chen,&nbsp;Baoyou Zhu,&nbsp;Hui Li,&nbsp;Xiaoyang Zhang","doi":"10.1029/2025EA004615","DOIUrl":"https://doi.org/10.1029/2025EA004615","url":null,"abstract":"<p>On the evening of 18 August 2022, a sequence of five gigantic jets (GJs) were recorded within 7 min over an isolated coastal thunderstorm approximately 170 km to the southwest of Luoding County, Guangdong Province of China. The thunderstorm exhibited a higher −10°C isotherm altitude (500 m above average), a significant CAPE value (∼2,158 J/kg), and a combination of weak low-level wind shear (&lt;3 m/s) and strong upper-level shear (∼14.5 m/s), composing favorable conditions for the GJ outbreak. GJs occurred during the developing-to-mature stage of the thunderstorm, characterized by the emergence of overshooting tops and cloud-top brightness temperatures below −70°C. Lightning activity was dominated by intracloud (IC) flashes, with IC frequency peaking at 47 events per 5-min interval around 20:10 UTC. High peak-current (&gt;−30 kA) negative cloud-to-ground (−CG) flashes, which were active prior to 19:50 UTC, disappeared approximately 10–15 min before the GJ outbreak began. Additionally, all five GJs were likely preceded by narrow bipolar events, which are typically regarded as the onset signatures of GJ parent lightning, consistent with previous observations.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025EA004615","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145272606","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":"An Investigation on Effect of Data Resolution on Vertical Wavenumber Spectrum of Gravity Waves From Radiosonde Observations","authors":"Fang Zheng Cheng,&nbsp;Kai Ming Huang,&nbsp;Shao Dong Zhang,&nbsp;Alan Z. Liu,&nbsp;Chun Ming Huang,&nbsp;Jun Li,&nbsp;Yun Gong,&nbsp;Zheng Ma,&nbsp;He He","doi":"10.1029/2025EA004486","DOIUrl":"https://doi.org/10.1029/2025EA004486","url":null,"abstract":"<p>Spectral structure of gravity waves (GWs) attracted much attention because it is related to wave dissipation mechanism and parameterization effect. Although many works have studied the spectral variation of GWs and attributed this change to factors such as height, season and latitude, impact of observational resolution on wave spectrum was rarely reported. By averaging and downsampling 5-m resolution radiosonde temperature, we construct two data sets with lower resolutions to investigate the effect of data resolution on vertical wavenumber spectrum of GWs. The constructed average and downsample data sets correspond to two measurement techniques in actual observations. The results indicate that a lower resolution causes a shallower slope of power spectrum density (PSD) due to its filter effect on high wavenumber spectrum close to the saturation spectrum. Nevertheless, there are some differences in spectral dependence on resolution between the two data. The shallowing slope is further enhanced in the downsample data due to significant increase of PSD amplitudes near maximum wavenumbers by superposition of subgrid scale perturbations, in contrast, slightly counteracted in the average data owing to weak attenuation of PSD amplitudes near maximum wavenumbers by smoothing. Hence, variation of observed wave spectrum may stem from resolution as well as data sampling technique, rather than only geophysical causes.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025EA004486","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145272334","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":"The Utility of a Hyperspectral Infrared Imager for Crewed Exploration of Planetary Bodies","authors":"C. I. Honniball,&nbsp;A. D. Rogers,&nbsp;K. E. Young,&nbsp;Z. Morse,&nbsp;B. Wolfe,&nbsp;C. Achilles,&nbsp;J. R. Ralleta,&nbsp;P. L. Whelley,&nbsp;P. G. Lucey,&nbsp;T. D. Glotch","doi":"10.1029/2024EA004056","DOIUrl":"https://doi.org/10.1029/2024EA004056","url":null,"abstract":"<p>Planetary analog simulations are a powerful exercise for understanding the utility of deployable instruments, their operational protocols, and the visualization of data products during ExtraVehicular Activities (EVAs). This paper presents results of a field campaign by the NASA Solar System Exploration Research Virtual Institute (SSERVI) Remote, In Situ and Synchrotron Studies for Science and Exploration-2 (RISE2) team to Kilbourne Hole, New Mexico in March/April 2023 to test the utility of a portable thermal infrared (TIR) hyperspectral imager (HSI) during four EVA simulations. The HSI provides emitted radiance spectra from 7 to 14 μm to map spectral variations likely caused by composition and physical properties, which allows HSI data products to aid in sample selection and site documentation. Four pairs of analog astronauts performed a mock EVA at three stations with field deployable instruments including an HSI. The HSI was found to be a useful tool for performing reconnaissance observations, field site documentation, and sample selection for visibly indistinct materials. From these analog simulations we prioritize two recommendations for use of HSI's in crewed missions. First, HSI-derived data products should be tailored for the specific science objectives and/or sampling objectives of the mission to expedite interpretation and decision-making. Second, the HSI instrument would ideally have a wide field-of-view/panoramic capability to reduce crew time selecting sites to image. Additionally, pre-EVA reconnaissance from a remotely operated rover could be conducted with an HSI to collect data prior to disturbance and again post human activity.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA004056","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145272333","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":"Airborne Lidar to Verify ICESat-2 Arctic Summer Sea Ice Heights and Melt Pond Depths: Calibration and Validation Campaign, Greenland 2022","authors":"Kutalmis Saylam,&nbsp;Aaron R. Averett,&nbsp;John R. Andrews,&nbsp;Shelby R. Short,&nbsp;Nathan T. Kurtz,&nbsp;Rachel L. Tilling","doi":"10.1029/2024EA004100","DOIUrl":"https://doi.org/10.1029/2024EA004100","url":null,"abstract":"<p>In July 2022, the National Aeronautics and Space Administration (NASA) funded an airborne lidar data acquisition campaign over the central Arctic Ocean to evaluate ICESat-2 ATLAS (Ice, Cloud, and Land Elevation Satellite, Advanced Topographic Laser Altimeter System) retrievals of summer sea ice heights and melt pond characteristics. A Leica Chiroptera-4x (CHIR) was mounted on a Gulfstream V aircraft with a glass viewport, alongside NASA's Land, Vegetation, and Ice Sensor (LVIS). Despite the operational constraints—including CHIR's low-altitude, slow-cruise constraints, and other logistical and environmental challenges—measurements nearly coincident with ICESat-2 observations were successfully collected. In total, 138 min of CHIR lidar data and four-band aerial imagery were acquired at 500 m altitude, mapping 11,000 km² of sea ice. Cross-check validation between CHIR and LVIS over a 31-km long swath demonstrated strong agreement (<i>R</i>² &gt; 0.98, RMSE = 0.045 m), confirming both the spatial accuracy and redundancy of the airborne measurements. A novel algorithm was developed to compare lidar data sets in a tide-free system by repositioning CHIR measurements to align with ICESat-2 observed points, accounting for drift speed (m/s) and heading (degrees), which significantly improved consistency. Comparisons between CHIR's near-infrared returns and ATL07 strong-beam products yielded an absolute height difference of 0.015 m with an agreement of <i>R</i>² = 0.73. Additionally, ATL03 photons showed a slight bias of 0.01 m and strong correspondence (<i>R</i>² = 0.84) with CHIR green-wavelength returns for coincident melt pond and lead depths in the height domain.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA004100","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145272013","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":"VIIRS Radiance Cluster Analysis in CrIS Observations for Enhanced Data Assimilation in NWP Models","authors":"Likun Wang,&nbsp;Lihang Zhou,&nbsp;Haibin Sun,&nbsp;Chris Burrow,&nbsp;Banghua Yan,&nbsp;Satya Kalluri","doi":"10.1029/2025EA004503","DOIUrl":"https://doi.org/10.1029/2025EA004503","url":null,"abstract":"<p>The Cross-track Infrared Sounder (CrIS) radiance data plays a crucial role in numerical weather prediction (NWP) models by providing essential atmospheric sounding information through data assimilation. However, challenges arise in handling subpixel cloud contamination within CrIS fields of view (FOVs), which can impact the accuracy of radiance simulations. To address this, the Visible Infrared Imaging Radiometer Suite (VIIRS) Radiances Cluster analysis within the CrIS FOVs is developed to characterize subpixel scene homogeneity. This paper describes the algorithms and data processing procedures for this cluster analysis. A fast and accurate collocation method was developed to directly align VIIRS measurements within CrIS FOVs using line-of-sight (LOS) pointing vectors. This method supports both terrain-corrected and non-terrain-corrected VIIRS geolocation data sets as inputs. The K-means clustering method is used to group collocated VIIRS radiance within CrIS FOVs into seven (7) clusters based on their radiance values. The mean, standard deviation, and coverage of each cluster are output for each CrIS FOV. Comparisons with the Infrared Atmospheric Sounding Interferometer cluster analysis demonstrate similar performance, confirming the validity of the CrIS-VIIRS approach. Data assimilation experiments at the European Centre for Medium-Range Weather Forecasts indicate that the VIIRS radiance cluster data can be effectively integrated into NWP models, aiding in cloud detection and improving data quality. These findings highlight the potential of CrIS-VIIRS clustering for enhancing data thinning, quality control, and assimilation of cloudy radiance observations in operational NWP systems.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025EA004503","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145271751","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":"Generation and Evaluation of Synthetic Low-Magnitude Earthquake Data Using Auxiliary Classifier GAN","authors":"Amjad Alsulami,&nbsp;Basem Al-Qadasi,&nbsp;Muhammad Usman,&nbsp;Umair Bin Waheed","doi":"10.1029/2024EA004064","DOIUrl":"https://doi.org/10.1029/2024EA004064","url":null,"abstract":"<p>Low-magnitude earthquakes occur far more frequently than major quakes and often go unnoticed by the public. These tremors rarely cause any damage, yet they play an important role in advancing our understanding of Earth's seismicity. Accurate detection of low-magnitude earthquakes is crucial to develop complete earthquake catalogs and improve seismic hazard forecasting models. However, conventional detection algorithms such as the short-time-average/long-time-average (STA/LTA) method struggle to identify these events because of their inherently low signal-to-noise ratio (SNR). Additionally, lack of labeled waveforms for low-magnitude earthquakes further complicates the training of effective deep-learning models. In this study, we use an Auxiliary Classifier Generative Adversarial Network (AC-GAN) to produce synthetic yet realistic three-component waveforms of low-magnitude earthquakes. The AC-GAN is trained on fixed-length (60-s) waveform segments conditioned by predefined SNR classes. All selected events have magnitudes lower than 3 and are categorized into 10 distinct SNR classes. Our results indicate that the AC-GAN model generates realistic three-component waveforms that effectively capture essential characteristics of real seismic signals. To evaluate the quality of these synthetic waveforms, we employ both quantitative and qualitative assessments. Quantitative analysis using Pearson's correlation coefficient yield relatively low correlations (ranging from 0.01 to 0.04); however, correlation values noticeably improve as SNR increases. Qualitatively, a user-based visual inspection experiment demonstrate remarkable similarities in general seismic features between the synthetic and authentic waveforms. We also test their effectiveness for data augmentation in binary deep-learning classifier designed for detecting low-magnitude earthquakes. Our result show improved classification performance with the addition of synthetic data.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024EA004064","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145271781","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":"Ionospheric Disturbances During the 4 December 2015, Mt. Etna Eruption","authors":"F. Ferrara,&nbsp;M. Ravanelli,&nbsp;A. Bonforte,&nbsp;V. Capparelli,&nbsp;V. Carbone,&nbsp;S. Scollo,&nbsp;L. Mereu,&nbsp;A. Cannata","doi":"10.1029/2025EA004214","DOIUrl":"https://doi.org/10.1029/2025EA004214","url":null,"abstract":"<p>This study presents the detection and characterization of co-volcanic ionospheric disturbances (CVIDs) associated with Mt. Etna's large-scale lava fountain (Italy). Leveraging a dense and proximal GNSS network, we identify local Total Electron Content (TEC) perturbations extending up to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>200 km south/southwest of the vent. The observed anomalies exhibit quasi-periodic signatures with amplitudes of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>0.6 TECU, periods of 15–25 min, and horizontal propagation velocities of 135–300 m<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>⋅</mo>\u0000 </mrow>\u0000 <annotation> $cdot $</annotation>\u0000 </semantics></math>s⁻¹, with dominant spectral power in the 0.5–1.5 mHz range, consistent with internal gravity waves. These signatures emerge gradually, 20–30 min after the seismo-acoustic onset of the eruption, coinciding with the rise of the volcanic plume. Eruption chronology is independently constrained using seismo-acoustic and thermal/visible imagery. Detection robustness is ensured via complementary spectral analyses (FFT and Empirical Mode Decomposition) and confirmed across multiple GNSS stations. The results suggest that open-conduit eruptive dynamics may facilitate sustained, gravity-dominated atmospheric forcing, generating subtle TEC disturbances that are otherwise difficult to detect under natural ionospheric variability. Comparison with prior studies, that did not detect such signals, highlights the critical role of near-field GNSS coverage. These findings contribute to a better understanding of CVID typologies and open new avenues for integrating ionospheric observations into multi-sensor volcanic monitoring frameworks. Further multi-event analyses are needed to generalize the proposed mechanisms and assess their utility in hazard forecasting.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025EA004214","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145271758","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":"Quasi-Constant Time Gap in Multiple Rings of Elves","authors":"The Pierre Auger Collaboration","doi":"10.1029/2025EA004321","DOIUrl":"https://doi.org/10.1029/2025EA004321","url":null,"abstract":"<p>We present evidence that the time delay between the multiple rings of elves is not caused by the ground reflection of the electromagnetic pulse produced by intracloud lightning. To investigate temporal differences of multi-elves, we analyzed data from four storms occurring at various times and distances from the Pierre Auger Observatory in Malargüe, Argentina. The Auger fluorescence detector's high temporal resolution of 100 ns enabled the frequent observation of multi-elves, accounting for approximately 23% of the events. By examining the traces of 70 double and 24 triple elves, we demonstrate that the time delay between the rings remains relatively constant regardless of the arc distance to the lightning. These results deviate from the trend expected from the electromagnetic pulse (EMP) ground reflection model, which predicts a decreasing time delay with increasing arc distance from an intracloud lightning at a given height. The first emission ring is due to a direct path of the EMP to the ionosphere, with the reflected EMP creating the second ring. Simulations conducted with this model demonstrate that short energetic in-cloud pulses can generate four-peak elves, and a temporal resolution of at least 25 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>μ</mi>\u0000 </mrow>\u0000 <annotation> ${upmu }$</annotation>\u0000 </semantics></math>s is required to separate them. Therefore, temporal resolution is crucial in the study of multi-elves. Our observations in the Córdoba province, central Argentina, indicate that the current understanding of the mechanism generating these phenomena may be incomplete, and further studies are needed to assess whether multi-elves are more likely related to the waveform shape of the lightning than to its altitude.</p>","PeriodicalId":54286,"journal":{"name":"Earth and Space Science","volume":"12 10","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025EA004321","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224284","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}