Pub Date : 2026-01-01Epub Date: 2025-12-01DOI: 10.1016/j.jastp.2025.106695
Hamza Gerçekcioğlu , Yahya Baykal
Utilizing the Rytov method in weakly turbulent oceanic medium, minimum scintillation index of sinusoidal Gaussian (SG) laser beams, named as the optimum beam (OB), is investigated for the underwater wireless optical communication (UWOC). Horizontal link between any underwater vehicles is considered. The formulation of the on-axis scintillation index of these beams is derived analytically, and the minimum scintillation index is determined with suitable adjustment of the complex displacement parameters. The complex displacement parameters are identified and tabulated for the selected propagation distance and source size. Obtained scintillation index results are drawn against the propagation length and source size. When compared with the plane, spherical, collimated, focused Gaussian, cos-Gaussian and cosh-Gaussian beams, OB is found to possess essential advantage. Additionally, with the obtained scintillation index values, probabilities of fade of these beams are calculated and their behaviors are also presented. OB also has a significant advantage when considering the fade probability.
{"title":"Mitigation of laser beam fluctuation and performance of probability of fade in weak ocean turbulence","authors":"Hamza Gerçekcioğlu , Yahya Baykal","doi":"10.1016/j.jastp.2025.106695","DOIUrl":"10.1016/j.jastp.2025.106695","url":null,"abstract":"<div><div>Utilizing the Rytov method in weakly turbulent oceanic medium, minimum scintillation index of sinusoidal Gaussian (SG) laser beams, named as the optimum beam (OB), is investigated for the underwater wireless optical communication (UWOC). Horizontal link between any underwater vehicles is considered. The formulation of the on-axis scintillation index of these beams is derived analytically, and the minimum scintillation index is determined with suitable adjustment of the complex displacement parameters. The complex displacement parameters are identified and tabulated for the selected propagation distance and source size. Obtained scintillation index results are drawn against the propagation length and source size. When compared with the plane, spherical, collimated, focused Gaussian, cos-Gaussian and cosh-Gaussian beams, OB is found to possess essential advantage. Additionally, with the obtained scintillation index values, probabilities of fade of these beams are calculated and their behaviors are also presented. OB also has a significant advantage when considering the fade probability.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106695"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-12-18DOI: 10.1016/j.jastp.2025.106704
Dave Broutman , Harold K. Knight , James W. Rottman , Stephen D. Eckermann
A wave-amplitude approximation adapted from inviscid WKB (Wentzel–Kramers–Brillouin) theory is tested for tsunami-generated gravity waves in the thermosphere up to 500 km altitude. The idea is to use a standard inviscid WKB wave-amplitude term , where is the vertical wavenumber and is the altitude, but to replace the inviscid with an obtained from a viscous and thermally diffusive dispersion relation. The approximation is implemented in an anelastic Fourier model for two-dimensional steady-state solutions in the tsunami reference frame. Comparisons are made with a more accurate numerical multilayer model giving solutions to a linearized system of anelastic governing equations. Though there is no perturbation analysis supporting the approximation for viscous , the approximation compares well with numerical multilayer solutions except for overestimating wave amplitudes in very strong viscosity. The overestimate is due to the neglect by the approximation of a coupling between upgoing gravity-wave and dissipative modes.
{"title":"Assessment of a simple wave-amplitude approximation for tsunami-generated gravity waves at all levels of viscosity in the thermosphere","authors":"Dave Broutman , Harold K. Knight , James W. Rottman , Stephen D. Eckermann","doi":"10.1016/j.jastp.2025.106704","DOIUrl":"10.1016/j.jastp.2025.106704","url":null,"abstract":"<div><div>A wave-amplitude approximation adapted from inviscid WKB (Wentzel–Kramers–Brillouin) theory is tested for tsunami-generated gravity waves in the thermosphere up to 500 km altitude. The idea is to use a standard inviscid WKB wave-amplitude term <span><math><msup><mrow><mi>m</mi></mrow><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math></span>, where <span><math><mrow><mi>m</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> is the vertical wavenumber and <span><math><mi>z</mi></math></span> is the altitude, but to replace the inviscid <span><math><mi>m</mi></math></span> with an <span><math><mi>m</mi></math></span> obtained from a viscous and thermally diffusive dispersion relation. The <span><math><msup><mrow><mi>m</mi></mrow><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math></span> approximation is implemented in an anelastic Fourier model for two-dimensional steady-state solutions in the tsunami reference frame. Comparisons are made with a more accurate numerical multilayer model giving solutions to a linearized system of anelastic governing equations. Though there is no perturbation analysis supporting the <span><math><msup><mrow><mi>m</mi></mrow><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math></span> approximation for viscous <span><math><mi>m</mi></math></span>, the approximation compares well with numerical multilayer solutions except for overestimating wave amplitudes in very strong viscosity. The overestimate is due to the neglect by the <span><math><msup><mrow><mi>m</mi></mrow><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math></span> approximation of a coupling between upgoing gravity-wave and dissipative modes.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106704"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-11-26DOI: 10.1016/j.jastp.2025.106693
Lian Lian
Accurate ultra-short-term wind speed prediction is of decisive significance for improving the grid connection efficiency of wind power generation, reducing the operation and maintenance costs of wind farms and maintaining the stable operation of wind power systems. This paper presents a prediction model based on improved sparrow search algorithm optimized extreme learning machine. Based on the standard sparrow search algorithm, three improved strategies including population initialization based on Piecewise chaotic map, improved position update of the discover and optimal value search are introduced to make the initial population evenly distributed and improve the global search performance and anti local minimum ability of the algorithm. The comparison of eight CEC2017 benchmark functions shows that the proposed improved sparrow search algorithm achieved the best optimization performance (mean and standard deviation) in six of them. The improved sparrow search algorithm is used to optimize the input weights and biases of hidden nodes in extreme learning machine model, which greatly improves the prediction accuracy of model. The performance of the model is evaluated by using the actual ultra-short-term wind speed dataset. In the experiment, autoregressive integrated moving average model in the statistical model, least squares support vector machine and extreme learning machine in the machine learning model, and Transformer, temporal convolutional network, graph neural network, bidirectional long short-term memory and convolutional neural network-long short-term memory in the deep learning model are selected as comparison models. The effectiveness of the proposed prediction model is verified by prediction error, performance indicators comparison, box plot, statistical index and Taylor chart. Compared with these ten comparison models, root mean square error decreased by 26.82 %–60.32 %, mean absolute error decreased by 27.21 %–60.12 %, mean absolute percentage error decreased by 24.60 %–59.84 %, relative root mean square error decreased by 29.00 %–147.16 %, square sum error decreased by 46.45 %–84.25 %, Theil Inequality coefficient decreased by 26.40 %–59.41 %, R square increased by 10.49 %–141.28 %, the index of agreement increased by 0.43 %–2.67 % and Pearson correlation coefficient increased by 3.14 %–20.49 %. At the same time, the training time of the proposed model is 372.0942 s, which can meet the requirements of the most common 15 min scheduling cycle in the actual wind farm management system, and provides an effective solution strategy for ultra-short-term wind speed prediction.
{"title":"Improved sparrow search algorithm optimized extreme learning machine for ultra-short-term wind speed prediction","authors":"Lian Lian","doi":"10.1016/j.jastp.2025.106693","DOIUrl":"10.1016/j.jastp.2025.106693","url":null,"abstract":"<div><div>Accurate ultra-short-term wind speed prediction is of decisive significance for improving the grid connection efficiency of wind power generation, reducing the operation and maintenance costs of wind farms and maintaining the stable operation of wind power systems. This paper presents a prediction model based on improved sparrow search algorithm optimized extreme learning machine. Based on the standard sparrow search algorithm, three improved strategies including population initialization based on Piecewise chaotic map, improved position update of the discover and optimal value search are introduced to make the initial population evenly distributed and improve the global search performance and anti local minimum ability of the algorithm. The comparison of eight CEC2017 benchmark functions shows that the proposed improved sparrow search algorithm achieved the best optimization performance (mean and standard deviation) in six of them. The improved sparrow search algorithm is used to optimize the input weights and biases of hidden nodes in extreme learning machine model, which greatly improves the prediction accuracy of model. The performance of the model is evaluated by using the actual ultra-short-term wind speed dataset. In the experiment, autoregressive integrated moving average model in the statistical model, least squares support vector machine and extreme learning machine in the machine learning model, and Transformer, temporal convolutional network, graph neural network, bidirectional long short-term memory and convolutional neural network-long short-term memory in the deep learning model are selected as comparison models. The effectiveness of the proposed prediction model is verified by prediction error, performance indicators comparison, box plot, statistical index and Taylor chart. Compared with these ten comparison models, root mean square error decreased by 26.82 %–60.32 %, mean absolute error decreased by 27.21 %–60.12 %, mean absolute percentage error decreased by 24.60 %–59.84 %, relative root mean square error decreased by 29.00 %–147.16 %, square sum error decreased by 46.45 %–84.25 %, Theil Inequality coefficient decreased by 26.40 %–59.41 %, R square increased by 10.49 %–141.28 %, the index of agreement increased by 0.43 %–2.67 % and Pearson correlation coefficient increased by 3.14 %–20.49 %. At the same time, the training time of the proposed model is 372.0942 s, which can meet the requirements of the most common 15 min scheduling cycle in the actual wind farm management system, and provides an effective solution strategy for ultra-short-term wind speed prediction.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106693"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-12-26DOI: 10.1016/j.jastp.2025.106709
Xia Pengfei , Zhang Weikang , Shu Liang , Guo Min
Ground-based GNSS tomography-derived three-dimensional water vapor products exhibit significant potential to enhance weather forecast accuracy. However, their accuracy is constrained by key technical challenges such as the vertical constraint function, the vertical division of the tomographic voxel, and the determination of the voxel's top height. This paper aims to optimize GNSS water vapor tomography by constructing a vertical factor model for water vapor density based on ERA5 reanalysis data and proposing a new method for determining the top height of the tomographic voxel. Furthermore, in accordance with the characteristics of water vapor distribution, the vertical level of the tomographic voxel is divided into two regions for non-uniform and uniform partitioning. Using observation data from ten GNSS stations in Wuhan for trial calculations, and by statistically analyzing the inversion results for the entire year of 2023, it is found that the optimized tomography technique not only enhances the utilization rate of GNSS rays but also improves the accuracy of GNSS three-dimensional water vapor density by up to 30.2 % in spring, with an annual average improvement of 24.2 %, enhancing severe weather prediction and numerical modeling.
{"title":"Enhanced ground-based GNSS tomography for accurate water vapor retrieval","authors":"Xia Pengfei , Zhang Weikang , Shu Liang , Guo Min","doi":"10.1016/j.jastp.2025.106709","DOIUrl":"10.1016/j.jastp.2025.106709","url":null,"abstract":"<div><div>Ground-based GNSS tomography-derived three-dimensional water vapor products exhibit significant potential to enhance weather forecast accuracy. However, their accuracy is constrained by key technical challenges such as the vertical constraint function, the vertical division of the tomographic voxel, and the determination of the voxel's top height. This paper aims to optimize GNSS water vapor tomography by constructing a vertical factor model for water vapor density based on ERA5 reanalysis data and proposing a new method for determining the top height of the tomographic voxel. Furthermore, in accordance with the characteristics of water vapor distribution, the vertical level of the tomographic voxel is divided into two regions for non-uniform and uniform partitioning. Using observation data from ten GNSS stations in Wuhan for trial calculations, and by statistically analyzing the inversion results for the entire year of 2023, it is found that the optimized tomography technique not only enhances the utilization rate of GNSS rays but also improves the accuracy of GNSS three-dimensional water vapor density by up to 30.2 % in spring, with an annual average improvement of 24.2 %, enhancing severe weather prediction and numerical modeling.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106709"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145879943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-12-02DOI: 10.1016/j.jastp.2025.106698
J.F. Nicolás, J. Crespo, E. Yubero, M. Alfosea-Simón, A. Clemente, N. Gómez-Sanchez, N. Galindo
In the present work, the contribution of PM2.5 sources to light absorption (σap,520) and scattering (σsp,525), as well as their impact on SSA values, was analysed. For this, measurements of aerosol optical properties and PM2.5 chemical composition were conducted at a rural site in southeastern Spain. The sources that significantly contributed to light extinction were: road traffic (TR), biomass burning (BB), mineral dust (MD), and a secondary aerosol source (SA). BB accounted for nearly 50 % of the absorption coefficient (λ = 520 nm), while the SA source exhibited the largest contribution to the scattering process (∼47 % at 525 nm). MD showed the smallest contribution to σap,520 and σsp,525, although its contribution significantly increased during Saharan dust events (SDEs). SSA daily values showed a clear dependence on the contribution of individual sources to PM2.5 concentrations. SSA values (λ = 525 nm) exceeding 0.90 were observed when contributions from secondary aerosols were greater than 50 %, while the SSA decreased with the increase in the contribution from road traffic. The contribution from BB was fairly constant for almost all SSA values, although high SSA values (>0.90) were observed when the contribution from this source was very low. The SSA showed a clear spectral dependence that varied according to the aerosol type. So, for BB aerosols the SSA decreased with wavelength, while for mineral dust the opposite trend was observed.
{"title":"The impact of PM2.5 sources on the single scattering albedo at a rural site in the south-western Mediterranean region","authors":"J.F. Nicolás, J. Crespo, E. Yubero, M. Alfosea-Simón, A. Clemente, N. Gómez-Sanchez, N. Galindo","doi":"10.1016/j.jastp.2025.106698","DOIUrl":"10.1016/j.jastp.2025.106698","url":null,"abstract":"<div><div>In the present work, the contribution of PM<sub>2.5</sub> sources to light absorption (σ<sub>ap,520</sub>) and scattering (σ<sub>sp,525</sub>), as well as their impact on SSA values, was analysed. For this, measurements of aerosol optical properties and PM<sub>2.5</sub> chemical composition were conducted at a rural site in southeastern Spain. The sources that significantly contributed to light extinction were: road traffic (TR), biomass burning (BB), mineral dust (MD), and a secondary aerosol source (SA). BB accounted for nearly 50 % of the absorption coefficient (λ = 520 nm), while the SA source exhibited the largest contribution to the scattering process (∼47 % at 525 nm). MD showed the smallest contribution to σ<sub>ap,520</sub> and σ<sub>sp,525</sub>, although its contribution significantly increased during Saharan dust events (SDEs). SSA daily values showed a clear dependence on the contribution of individual sources to PM<sub>2.5</sub> concentrations. SSA values (λ = 525 nm) exceeding 0.90 were observed when contributions from secondary aerosols were greater than 50 %, while the SSA decreased with the increase in the contribution from road traffic. The contribution from BB was fairly constant for almost all SSA values, although high SSA values (>0.90) were observed when the contribution from this source was very low. The SSA showed a clear spectral dependence that varied according to the aerosol type. So, for BB aerosols the SSA decreased with wavelength, while for mineral dust the opposite trend was observed.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106698"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-11-26DOI: 10.1016/j.jastp.2025.106692
Akshay S. Patil , Aditi D. Yadav , Bhushan Vibhute , Dada P. Nade , T. Dharmaraj , Sambhaji M. Pawar , Sunil D. Pawar
Severe convective systems such as tropical cyclones and thunderstorms play a vital role in vertically coupling the Earth's atmosphere, often driving perturbations from the lower troposphere to the upper ionosphere. During the passage of Extremely Severe Cyclonic Storm (ESCS) Tauktae over the Arabian Sea in May 2021, this study examines the interactions between the atmosphere and ionosphere. We employ a multi-instrumental strategy that combines GNSS-based Total Electron Content (TEC) observations from the Indian Institute of Science (IISc) Bangalore, mesospheric temperature profiles from the SABER instrument onboard the TIMED satellite, and lightning data from the Indian Lightning Location Network (ILLN). Strong thermal disturbances and gravity wave signatures were observed in the mesosphere-lower thermosphere area on May 15–16, coinciding with a noticeable increase in lightning activity. Concurrently, short-period TEC fluctuations with peak power in the 1–2 mHz band were observed, indicating travelling ionospheric disturbances (TIDs). The temporal alignment of lightning peaks, gravity wave signatures, and TEC anomalies suggests efficient coupling between the troposphere and ionosphere during the cyclone. These findings support the concept of gravity wave-mediated coupling between the troposphere and ionosphere during extreme weather events.
{"title":"Ionospheric response to lightning activity during cyclone Tauktae over the Arabian Sea","authors":"Akshay S. Patil , Aditi D. Yadav , Bhushan Vibhute , Dada P. Nade , T. Dharmaraj , Sambhaji M. Pawar , Sunil D. Pawar","doi":"10.1016/j.jastp.2025.106692","DOIUrl":"10.1016/j.jastp.2025.106692","url":null,"abstract":"<div><div>Severe convective systems such as tropical cyclones and thunderstorms play a vital role in vertically coupling the Earth's atmosphere, often driving perturbations from the lower troposphere to the upper ionosphere. During the passage of Extremely Severe Cyclonic Storm (ESCS) Tauktae over the Arabian Sea in May 2021, this study examines the interactions between the atmosphere and ionosphere. We employ a multi-instrumental strategy that combines GNSS-based Total Electron Content (TEC) observations from the Indian Institute of Science (IISc) Bangalore, mesospheric temperature profiles from the SABER instrument onboard the TIMED satellite, and lightning data from the Indian Lightning Location Network (ILLN). Strong thermal disturbances and gravity wave signatures were observed in the mesosphere-lower thermosphere area on May 15–16, coinciding with a noticeable increase in lightning activity. Concurrently, short-period TEC fluctuations with peak power in the 1–2 mHz band were observed, indicating travelling ionospheric disturbances (TIDs). The temporal alignment of lightning peaks, gravity wave signatures, and TEC anomalies suggests efficient coupling between the troposphere and ionosphere during the cyclone. These findings support the concept of gravity wave-mediated coupling between the troposphere and ionosphere during extreme weather events.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106692"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-12-10DOI: 10.1016/j.jastp.2025.106703
Jiantao Liu , Yibing Liu , Chao Zhou , Qingfeng Gao , Haolin Yin
In wind turbine fatigue damage assessment, commonly used wind spectrum models often deviate from actual wind power spectral density (PSD). Directly using these spectra to generate simulated wind fields leads to deviations in fatigue assessment results. Addressing this issue, this study focuses on wind turbine blades to compare damage fatigue accuracy under different fitting target spectra. First, the integral scale parameter-related terms and denominator exponent terms in the Kaimal spectrum were designated as parameters to be fitted, proposing a three-parameter fitting model. Then, the classic periodogram-estimated spectrum of measured wind speed data was calculated, and blade damage values under the wind field generated from this spectrum were regarded as estimated actual damage values. Finally, damage assessment accuracy was compared between least squares fitted spectra using the classic periodogram-estimated spectrum as the target spectrum and those using the Welch-estimated spectrum as the target spectrum, while quantitatively comparing their improvement degrees over the Kaimal spectrum.
{"title":"Influence of target spectrum selection in wind spectrum fitting on fatigue damage assessment accuracy for wind turbine blades","authors":"Jiantao Liu , Yibing Liu , Chao Zhou , Qingfeng Gao , Haolin Yin","doi":"10.1016/j.jastp.2025.106703","DOIUrl":"10.1016/j.jastp.2025.106703","url":null,"abstract":"<div><div>In wind turbine fatigue damage assessment, commonly used wind spectrum models often deviate from actual wind power spectral density (PSD). Directly using these spectra to generate simulated wind fields leads to deviations in fatigue assessment results. Addressing this issue, this study focuses on wind turbine blades to compare damage fatigue accuracy under different fitting target spectra. First, the integral scale parameter-related terms and denominator exponent terms in the Kaimal spectrum were designated as parameters to be fitted, proposing a three-parameter fitting model. Then, the classic periodogram-estimated spectrum of measured wind speed data was calculated, and blade damage values under the wind field generated from this spectrum were regarded as estimated actual damage values. Finally, damage assessment accuracy was compared between least squares fitted spectra using the classic periodogram-estimated spectrum as the target spectrum and those using the Welch-estimated spectrum as the target spectrum, while quantitatively comparing their improvement degrees over the Kaimal spectrum.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106703"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145796868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-11-20DOI: 10.1016/j.jastp.2025.106687
Ting Zhang , Yifu Luo , Bin Zhang , Fang Jiang , Tianfang Wang , Si Xiao , Xuesong Bai , Liping Fu
The equatorial plasma bubble (EPB) is one of the most important phenomena in the Earth's ionosphere. In this paper, we propose a method for the EPB image data processing and automatic labeling, utilizing the Global-scale Observations of the Limb and Disk (GOLD) 135.6 nm nightglow data. The method extracts the central position of EPBs, significantly reducing the workload of manual labeling. Through manual analysis, a dataset of 1,380 image samples was established. Based on the unique features of EPB images, a deep learning model was developed to improve detection accuracy. After optimization and validation, the YOLO-LessHead model achieved a mean Average Precision ([email protected]) of 78.39 %, enabling automatic and accurate identification of EPB images. We used the developed model to identify and statistically analyze the GOLD airglow image data from October 2018 to December 2024. The results indicate that EPB occurrence rates show strong seasonal and longitudinal variability, with distinct seasonal patterns across different longitudes. The zonal drift velocities of EPBs increase with enhanced solar radio flux (F10.7) and decrease as geomagnetic activity (Ap index) intensifies. Drift speeds are generally higher and more variable at the magnetic equator, while the northern and southern EIA regions exhibit similar values and trends.
赤道等离子体泡是地球电离层中最重要的现象之一。本文提出了一种利用GOLD (Global-scale Observations of the Limb and Disk) 135.6 nm夜光数据对EPB图像数据进行处理和自动标记的方法。该方法提取epb的中心位置，大大减少了人工标记的工作量。通过人工分析，建立了1380个图像样本的数据集。基于EPB图像的独特特征，开发了一种深度学习模型来提高检测精度。经过优化和验证，YOLO-LessHead模型的平均平均精度（[email protected]）达到78.39%，实现了EPB图像的自动准确识别。利用该模型对2018年10月至2024年12月的GOLD气辉图像数据进行识别和统计分析。结果表明，EPB的发生具有较强的季节和纵向变异性，在不同的经度上具有明显的季节特征。epb的纬向漂移速度随太阳射电通量（F10.7）的增强而增大，随地磁活动（Ap指数）的增强而减小。在磁赤道，漂移速度一般较高，变化更大，而北部和南部的EIA区域表现出相似的值和趋势。
{"title":"Automatic detection of equatorial plasma bubbles using deep neural networks","authors":"Ting Zhang , Yifu Luo , Bin Zhang , Fang Jiang , Tianfang Wang , Si Xiao , Xuesong Bai , Liping Fu","doi":"10.1016/j.jastp.2025.106687","DOIUrl":"10.1016/j.jastp.2025.106687","url":null,"abstract":"<div><div>The equatorial plasma bubble (EPB) is one of the most important phenomena in the Earth's ionosphere. In this paper, we propose a method for the EPB image data processing and automatic labeling, utilizing the Global-scale Observations of the Limb and Disk (GOLD) 135.6 nm nightglow data. The method extracts the central position of EPBs, significantly reducing the workload of manual labeling. Through manual analysis, a dataset of 1,380 image samples was established. Based on the unique features of EPB images, a deep learning model was developed to improve detection accuracy. After optimization and validation, the YOLO-LessHead model achieved a mean Average Precision ([email protected]) of 78.39 %, enabling automatic and accurate identification of EPB images. We used the developed model to identify and statistically analyze the GOLD airglow image data from October 2018 to December 2024. The results indicate that EPB occurrence rates show strong seasonal and longitudinal variability, with distinct seasonal patterns across different longitudes. The zonal drift velocities of EPBs increase with enhanced solar radio flux (F10.7) and decrease as geomagnetic activity (Ap index) intensifies. Drift speeds are generally higher and more variable at the magnetic equator, while the northern and southern EIA regions exhibit similar values and trends.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106687"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-12-24DOI: 10.1016/j.jastp.2025.106708
Landi Zhong , Haibo Zou , Xiaoyou Long , Jiaxin Wang , Yige Huang
This study presents an improved fuzzy logic-based algorithm, originally developed for the U.S. Weather Surveillance Radar-1988 Doppler (WSR-88D) system, to classify meteorological echoes (MS) and non-meteorological echoes (non-MS) in S-band dual-polarization radar data from China New Generation Weather Radar (CINRAD) with S-band of type A (SA). In the improvement process, the "true" MS and non-MS are identified firstly using the combination of a single-polarization radar technique for distinguishing the MS and non-MS from 73,423 radar records and then manual inspection. Subsequently, a statistical analysis of dual-polarization variables and their derived parameters is conducted to obtain the characteristics of the MS and non-MS. Finally, the membership function parameters in the fuzzy logic-based algorithm are refined based on these characteristics. The performance of the improved algorithm is evaluated under four weather scenarios: clear-sky, weak precipitation, heavy precipitation and typhoon. The results demonstrate that the improved algorithm effectively distinguishes between non-MS and MS, with outcomes that align well with real echo data. In practical applications, the improved algorithm markedly reduces residual non-MS contamination while preserving the MS. In order to assess the improved algorithm more comprehensively, 7339 radar samples randomly collected at Nanchang radar station from January to November 2023 are used for the statistical evaluation of the algorithm. Results reveal that the improved algorithm eliminates the majority of the non-MS while maintaining the integrity of MS structures. In contrast, the original algorithm has limited capability in filtering the non-MS, particularly near radar stations and mountainous regions. Overall, the results demonstrate that the improved algorithm substantially enhances data quality control and accuracy in the application of CINRAD/SA radar products.
{"title":"Optimized fuzzy logic algorithm for classifying meteorological and non-meteorological echoes in CINRAD/SA data in Poyang Lake region","authors":"Landi Zhong , Haibo Zou , Xiaoyou Long , Jiaxin Wang , Yige Huang","doi":"10.1016/j.jastp.2025.106708","DOIUrl":"10.1016/j.jastp.2025.106708","url":null,"abstract":"<div><div>This study presents an improved fuzzy logic-based algorithm, originally developed for the U.S. Weather Surveillance Radar-1988 Doppler (WSR-88D) system, to classify meteorological echoes (MS) and non-meteorological echoes (non-MS) in S-band dual-polarization radar data from China New Generation Weather Radar (CINRAD) with S-band of type A (SA). In the improvement process, the \"true\" MS and non-MS are identified firstly using the combination of a single-polarization radar technique for distinguishing the MS and non-MS from 73,423 radar records and then manual inspection. Subsequently, a statistical analysis of dual-polarization variables and their derived parameters is conducted to obtain the characteristics of the MS and non-MS. Finally, the membership function parameters in the fuzzy logic-based algorithm are refined based on these characteristics. The performance of the improved algorithm is evaluated under four weather scenarios: clear-sky, weak precipitation, heavy precipitation and typhoon. The results demonstrate that the improved algorithm effectively distinguishes between non-MS and MS, with outcomes that align well with real echo data. In practical applications, the improved algorithm markedly reduces residual non-MS contamination while preserving the MS. In order to assess the improved algorithm more comprehensively, 7339 radar samples randomly collected at Nanchang radar station from January to November 2023 are used for the statistical evaluation of the algorithm. Results reveal that the improved algorithm eliminates the majority of the non-MS while maintaining the integrity of MS structures. In contrast, the original algorithm has limited capability in filtering the non-MS, particularly near radar stations and mountainous regions. Overall, the results demonstrate that the improved algorithm substantially enhances data quality control and accuracy in the application of CINRAD/SA radar products.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106708"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01Epub Date: 2025-12-24DOI: 10.1016/j.jastp.2025.106710
T.L. Gulyaeva
Ionospheric inhomogeneities have shown asymmetry in the Arctic and Antarctic, but the extent of similar effects from pole to magnetic equator remains less investigated. Here we present a Net Volume index (NT) characterizing the deviation of the total electron content, dTEC, from the quiet reference in 6 bands of magnetic latitude, Φ: two auroral zones exceeding ±60°, two ranges in the middle latitudes between ±40° and ±60°, and two subequatorial zones from ±2.5° to ±37.5°. The NT instantaneous index is derived from the JPL GIM-TEC converted to a geomagnetic coordinate system. The observed dTEC ionospheric anomalies during three severe magnetic storms (May 11, 2024, January 1, 2025, and June 1, 2025) illustrate the diversity of NT storm profiles across six magnetic latitude ranges. The total sample of 97 intense storms was selected according to the criteria of synchronous occurrence of the merged interplanetary electric field Em ≥ 5 mW/m, geomagnetic indices Hpo ≥ 7 i.u., Apo ≥ 132 nT, Dst ≤ −100 nT and the planetary ionospheric index Wp ≥ 5 i.u. from 1995 to 2025. Superimposed epoch analysis was performed with zero epoch time, t0 = 0, set at Apo peak, main storm phase within 24 h preceding t0, and recovering phase within 47 h thereafter. The reference quiet TECq was selected from GIM-TEC during 24 h before the main phase, from t0-48h to t0-25h. Asymmetry of the ionospheric anomalies of the positive peak dTECp > 0 and the negative peak dTECn < 0 was observed in the Northern and Southern hemispheres in all 6 Φ zones, with the intensity gradually decreasing from pole to magnetic equator. For the first time in the literature, the intensity of the geomagnetic storm, Apo peak, is determined by ionospheric anomalies (range ΔdTEC = dTECmax – dTECmin) and the intensity of the interplanetary electric field Em during the main phase of the storm. The opposite scenario is used to estimate the intensity of the ionospheric storm, dTECp and dTECn, in six magnetic latitudinal zones depending on the peak of Apo and season (day of year) during the recovery phase.
{"title":"Sequence of space storm effects in ionospheric anomalies and geomagnetic activity","authors":"T.L. Gulyaeva","doi":"10.1016/j.jastp.2025.106710","DOIUrl":"10.1016/j.jastp.2025.106710","url":null,"abstract":"<div><div>Ionospheric inhomogeneities have shown asymmetry in the Arctic and Antarctic, but the extent of similar effects from pole to magnetic equator remains less investigated. Here we present a Net Volume index (NT) characterizing the deviation of the total electron content, dTEC, from the quiet reference in 6 bands of magnetic latitude, Φ: two auroral zones exceeding ±60°, two ranges in the middle latitudes between ±40° and ±60°, and two subequatorial zones from ±2.5° to ±37.5°. The NT instantaneous index is derived from the JPL GIM-TEC converted to a geomagnetic coordinate system. The observed dTEC ionospheric anomalies during three severe magnetic storms (May 11, 2024, January 1, 2025, and June 1, 2025) illustrate the diversity of NT storm profiles across six magnetic latitude ranges. The total sample of 97 intense storms was selected according to the criteria of synchronous occurrence of the merged interplanetary electric field Em ≥ 5 mW/m, geomagnetic indices Hpo ≥ 7 i.u., Apo ≥ 132 nT, Dst ≤ −100 nT and the planetary ionospheric index Wp ≥ 5 i.u. from 1995 to 2025. Superimposed epoch analysis was performed with zero epoch time, t<sub>0</sub> = 0, set at Apo peak, main storm phase within 24 h preceding t<sub>0</sub>, and recovering phase within 47 h thereafter. The reference quiet TECq was selected from GIM-TEC during 24 h before the main phase, from t<sub>0</sub>-48h to t<sub>0</sub>-25h. Asymmetry of the ionospheric anomalies of the positive peak dTECp > 0 and the negative peak dTECn < 0 was observed in the Northern and Southern hemispheres in all 6 Φ zones, with the intensity gradually decreasing from pole to magnetic equator. For the first time in the literature, the intensity of the geomagnetic storm, Apo peak, is determined by ionospheric anomalies (range ΔdTEC = dTECmax – dTECmin) and the intensity of the interplanetary electric field Em during the main phase of the storm. The opposite scenario is used to estimate the intensity of the ionospheric storm, dTECp and dTECn, in six magnetic latitudinal zones depending on the peak of Apo and season (day of year) during the recovery phase.</div></div>","PeriodicalId":15096,"journal":{"name":"Journal of Atmospheric and Solar-Terrestrial Physics","volume":"278 ","pages":"Article 106710"},"PeriodicalIF":1.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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