Radio Science最新文献

The geomagnetic storm time responses of the TEC, foF2, and hmF2 in different solar activity during solar cycle 24 and 25 第24和25太阳活动周TEC、foF2和hmF2在不同太阳活动条件下的地磁风暴时间响应

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS007961

Yekoye Asmare Tariku

{"title":"The geomagnetic storm time responses of the TEC, foF2, and hmF2 in different solar activity during solar cycle 24 and 25","authors":"Yekoye Asmare Tariku","doi":"10.1029/2024RS007961","DOIUrl":"https://doi.org/10.1029/2024RS007961","url":null,"abstract":"This paper mainly examines the response of variation of the TEC, foF2, and hmF2 obtained from observations (GPS and digisondes) and models (IRI 2016 and IRI-Plas 2017) across low-to-high latitudes during various geomagnetic storm time conditions in different solar activity years. The 19 February 2014, 17 March 2015, and 4 November 2021 geomagnetic storm cases caused positive storm effects (particularly at low latitudes), while the 8 September 2017, and 26 August 2018 geomagnetic storm cases resulted in negative storm effects, especially at mid and high latitudes. Furthermore, during the 19 February 2014 storm, the sharp increase (peak) diurnal digisondes TEC values are observed, on average, when the hmF2 values reach about 360, 282, and 312 km, in the low, mid and high latitudes, respectively. During the 26 August 2018 storm, the peak TEC values are observed, on average, when the hmF2 values reach about 313, 258, and 268 km in the low, mid and high latitudes, respectively. Hence, the digisonde-derived peak TEC in mid latitudes typically coincides with a decrease in hmF2, while in low latitudes, it is associated with an increase in hmF2. Additionally, during low solar activity periods, digisonde-derived peak TEC values were observed when hmF2 decreased, contrasting with patterns seen during high solar activity. Both the IRI 2016 and IRI-Plas 2017 models performed well, with the models peak TEC values being observed when the hmF2 variations attain similar values with the observations, reinforcing the models' reliability in capturing ionospheric responses during geomagnetic storms.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-18"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905768","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}

引用次数: 0

The impact and sources of radio frequency interference on GNSS signals 无线电频率干扰对GNSS信号的影响及来源

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS008109

Endawoke Yizengaw

{"title":"The impact and sources of radio frequency interference on GNSS signals","authors":"Endawoke Yizengaw","doi":"10.1029/2024RS008109","DOIUrl":"https://doi.org/10.1029/2024RS008109","url":null,"abstract":"The utilization of the global navigation satellite systems (GNSS) services in both military and civilian applications as well as for scientific investigation has grown exponentially. However, the increasing reliance on GNSS applications has raised concerns about potential risks from intentional radio frequency interference (RFI) transmitters. RFI significantly affects GNSS's environmental monitoring capabilities by inflating the scintillation index and misleading the scientific community with scintillation indices not attributable to ionospheric dynamic events. Consequently, the existing climatological distribution of GNSS scintillations may require careful reevaluation, as it may not adequately filter out RFI induced scintillations. Thus, characterizing the global RFI occurrence regions and developing real-time detection capabilities to mitigate its effects is critically important. Leveraging GNSS measurements from ground stations and six COSMIC-2 satellite constellations, we have developed a technique to detect RFI events and identify RFI active regions. Additionally, for the first time, we have implemented techniques that differentiate RFI associated scintillations from scintillations caused by ionospheric turbulence.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905915","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}

引用次数: 0

Optimization of variational mode decomposition using stationary wavelet transform and its application to transient electromagnetic signal noise reduction 平稳小波变换的变分模态分解优化及其在瞬变电磁信号降噪中的应用

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2023RS007889

Xianxia Wang;Xiaoya Wei;Duxi Song;Linfei Wang;Haochen Wang;Zhicheng Zhang;Tingye Qi

{"title":"Optimization of variational mode decomposition using stationary wavelet transform and its application to transient electromagnetic signal noise reduction","authors":"Xianxia Wang;Xiaoya Wei;Duxi Song;Linfei Wang;Haochen Wang;Zhicheng Zhang;Tingye Qi","doi":"10.1029/2023RS007889","DOIUrl":"https://doi.org/10.1029/2023RS007889","url":null,"abstract":"To solve the problem of signal loss due to local reconstruction in the variational mode decomposition (VMD) method, this study proposes to use the stationary wavelet transform (SWT) to extract the effective signal in the mixed noise modes and reconstruct the noise-reduced signal. First the slime mold algorithm (SMA) takes to realize the adaptive difficulty of selecting the important parameters K (the number of eigenmode decompositions) and a (the quadratic penalty coefficient) in the VMD. Then, the VMD decomposed modes are divided into the basic signal and noise signal according to the definition of Euclidean distance, finally the noise signal is decomposed in a new step by using SWT, and the basic signal is reconstructed with the effective signal to get the final noise reduced signal. Through the establishment of simulation tests and transient electromagnetic field tests in the mined-out area, the results show that the VMD-SWT method exhibits a better denoising effect and higher inversion accuracy for the transient electromagnetic signals, proving the superiority and applicability.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-18"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905912","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}

引用次数: 0

Finite element method modeling of the wire thickness of a monopole on a circular ground plane 圆形地平面上单极子导线厚度的有限元建模

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS008068

C. G. Hynes;R. G. Vaughan

引用次数: 0

Imaging of the ionosphere and plasmasphere using GNSS slant TEC obtained from LEO satellites 利用低轨道卫星获得的GNSS倾斜TEC对电离层和等离子层进行成像

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS008058

Lucas Schreiter;Andreas Brack;Benjamin Männel;Harald Schuh;Daniel Arnold;Adrian Jäggi

{"title":"Imaging of the ionosphere and plasmasphere using GNSS slant TEC obtained from LEO satellites","authors":"Lucas Schreiter;Andreas Brack;Benjamin Männel;Harald Schuh;Daniel Arnold;Adrian Jäggi","doi":"10.1029/2024RS008058","DOIUrl":"https://doi.org/10.1029/2024RS008058","url":null,"abstract":"Satellites with dual-frequency Global Navigation Satellite Systems (GNSS) receivers can measure integrated electron density, known as slant Total Electron Content (sTEC), between the receiver and transmitter. Precise relative variations of sTEC are achievable using phase measurements on L1 and L2 frequencies, yielding an accuracy of around 0.1 TECU or better. However, CubeSats like Spire LEMUR, with simpler setups (e.g., patch antennas) and code noise in the order of several meters, face limitations in accuracy. Their precision, determined by phase observations, remains in the 0.1–0.3 TECU range. With a substantial number of observations and comprehensive coverage of lines of sight between Low Earth Orbit (LEO) and GNSS satellites, global electron density can be reconstructed from sTEC measurements. Utilizing 27 satellites from various missions, including Swarm, Gravity Recovery And Climate Experiment Follow-On, Jason-3, Sentinel 1/2/3, COSMIC-2, and Spire CubeSats, a cubic B-spline expansion in magnetic latitude, magnetic local time, and altitude is employed to model the logarithmic electron density. Hourly snapshots of the three-dimensional electron density are generated, adjusting the model parameters through non-linear least squares based on sTEC observations. Results demonstrate that including Spire significantly enhances estimates, showcasing exceptional agreement with in situ observations from Swarm and Defense Meteorological Satellite Program LEO satellites. The model outperforms contemporary climatological models, such as International Reference Ionosphere (IRI)-2020 and the neural network-based NET model. Validation efforts include comparisons with ground-based sTEC measurements, space-based vertical TEC from Jason-3 altimetry, and global TEC maps from the Center for Orbit Determination in Europe and the German Research Center for Geosciences (GFZ).","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-19"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905943","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}

引用次数: 0

Front matters 前面问题

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1002/rds.21248

引用次数: 0

Efficient storage of embedded element patterns for low frequency radio telescopes 低频射电望远镜嵌入式元件模式的有效存储

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS008080

David B. Davidson;Adrian T. Sutinjo

{"title":"Efficient storage of embedded element patterns for low frequency radio telescopes","authors":"David B. Davidson;Adrian T. Sutinjo","doi":"10.1029/2024RS008080","DOIUrl":"https://doi.org/10.1029/2024RS008080","url":null,"abstract":"The use of spherical modes offers an efficient solution for storing embedded element patterns with significant angular structure for large scale arrays, such as the Square Kilometer Array (SKA)-Low radio telescope. These patterns are required for calibration of the numerous stations comprising the telescope, each containing several hundred elements, and operating over a 7:1 bandwidth. However, implementation is significantly complicated by the many differences in the notation used in the literature for the Legendre special functions. The differing phasor conventions used in electrical engineering and physics further complicate this. This paper synthesizes much of the existing literature on this topic, paying special attention to these issues. Mathematical implementation issues are also addressed. A number of suitable tests using canonical dipole radiators to verify correct implementation are outlined. The paper concludes with tests on an individual SKALA4 antenna and a full-scale SKA-Low prototype station comprising 256 of these antennas. The storage saving afforded is some three orders of magnitude; this is very significant for a full SKA-Low station. Supporting material summarizes differing formulations and conventions encountered in the literature.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-15"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905913","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}

引用次数: 0

Automatic segmentation model and parameter extraction algorithm for lightning whistlers 雷电口哨自动分割模型及参数提取算法

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2024RS007984

Tian Xiang;Moran Liu;Shimin He;Xiang Wang;Chen Zhou

{"title":"Automatic segmentation model and parameter extraction algorithm for lightning whistlers","authors":"Tian Xiang;Moran Liu;Shimin He;Xiang Wang;Chen Zhou","doi":"10.1029/2024RS007984","DOIUrl":"https://doi.org/10.1029/2024RS007984","url":null,"abstract":"Based on the magnetic field data recorded by the ZH-1 electromagnetic satellite, we cerat a training set of 1,300 spectrograms containing the dispersion spectrum of lightning whistlers (LW). The Segment Anything Model (SAM) in the field of image segmentation is trained through the training set to obtain a fine-tuned SAM model that can be used to detect and segment the dispersion spectrum of LW at pixel level. All track regions of LW are effectively separated from other non-lightning whistlers regions in the spectrograms after being segmented by the model. The segmentation effect is excellent and detection accuracy is 96.89%, which is better than the previous segmentation model for LW based on ground station data. Then we apply the traditional image processing methods to extract the dispersion spectrum of LW one by one, and develop an algorithm to automatically extract the physical parameters of each LW. The root mean square error between the automatically extracted dispersion parameter and the manually extracted dispersion parameter is only 0.1654 s\u0000<sup>1/2</sup>\u0000. The model and algorithm studied in this paper are employed to analyze the dispersion of LW received by the ZH-1 satellite over China. It is found that the whistlers dispersion received by satellites during summer in the northern hemisphere and summer in the southern hemisphere shows opposite trends with receiving latitude. Both trends can be explained by the relationship between the dispersion and the length of propagation paths of LW.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 11","pages":"1-14"},"PeriodicalIF":1.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777717","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}

引用次数: 0

Spatial-temporal analysis of inter tropical discontinuity influence on radio signal behavior in Nigeria 热带间断性对尼日利亚无线电信号行为影响的时空分析

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2024RS008006

I. Emmanuel;O. S. Ojo;G. O. Emmanuel;K. D. Adedayo

引用次数: 0

Electromagnetic energy propagation through rock of low loss tangent 电磁能在低损耗切线岩石中的传播

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2024RS008076

B. A. Austin

引用次数: 0