Using a machine learning technique called echo state network (ESN), we have developed an emulator to model the physics-based global magnetohydrodynamic simulation results of REPPU (REProduce Plasma Universe) code. The inputs are the solar wind time series with date and time, and the outputs are the time series of the ionospheric auroral current system in the form of two-dimensional (2D) patterns of field-aligned current, potential, and conductivity. We mediated a principal component analysis for a dimensionality reduction of the 2D map time series. In this study, we report the latest upgraded Surrogate Model for REPPU Auroral Ionosphere version 2 (SMRAI2) with significantly improved resolutions in time and space (5 min in time, ∼1° in latitude, and 4.5° in longitude), where the dipole tilt angle is also newly added as one of the input parameters to reproduce the seasonal dependence. The fundamental dependencies of the steady-state potential and field-aligned current patterns on the interplanetary magnetic field directions are consistent with those obtained from empirical models. Further, we show that the ESN-based emulator can output the AE index so that we can evaluate the performance of the dynamically changing results, comparing with the observed AE index. Since the ESN-based emulator runs a million times faster than the REPPU simulation, it is promising that we can utilize the emulator for the real-time space weather forecast of the auroral current system as well as to obtain large-number ensembles to achieve future data assimilation-based forecast.
{"title":"Machine Learning-Based Emulator for the Physics-Based Simulation of Auroral Current System","authors":"Ryuho Kataoka, Aoi Nakamizo, Shinya Nakano, Shigeru Fujita","doi":"10.1029/2023sw003720","DOIUrl":"https://doi.org/10.1029/2023sw003720","url":null,"abstract":"Using a machine learning technique called echo state network (ESN), we have developed an emulator to model the physics-based global magnetohydrodynamic simulation results of REPPU (REProduce Plasma Universe) code. The inputs are the solar wind time series with date and time, and the outputs are the time series of the ionospheric auroral current system in the form of two-dimensional (2D) patterns of field-aligned current, potential, and conductivity. We mediated a principal component analysis for a dimensionality reduction of the 2D map time series. In this study, we report the latest upgraded Surrogate Model for REPPU Auroral Ionosphere version 2 (SMRAI2) with significantly improved resolutions in time and space (5 min in time, ∼1° in latitude, and 4.5° in longitude), where the dipole tilt angle is also newly added as one of the input parameters to reproduce the seasonal dependence. The fundamental dependencies of the steady-state potential and field-aligned current patterns on the interplanetary magnetic field directions are consistent with those obtained from empirical models. Further, we show that the ESN-based emulator can output the AE index so that we can evaluate the performance of the dynamically changing results, comparing with the observed AE index. Since the ESN-based emulator runs a million times faster than the REPPU simulation, it is promising that we can utilize the emulator for the real-time space weather forecast of the auroral current system as well as to obtain large-number ensembles to achieve future data assimilation-based forecast.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"46 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139079549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Satellite navigation based on the Global Navigation Satellite System can provide aircraft with more precise guidance and increase flight efficiency. However, severe space weather events can cause satellite navigation failure due to the dramatic increase in total electron content and irregularities in the ionosphere. Consequently, ground navigation has to be used to replace satellite navigation, increasing aircraft separation standards and reducing airspace capacity. As a result, numerous flights may be delayed or even canceled, incurring significant financial losses. The occurrence peak of space weather events generally coincides with the 11-year-cycle solar maximum, and 2025 is expected to be the upcoming solar maximum. The Greater Bay Area (GBA), located in the equatorial ionization anomaly region of China, is particularly vulnerable to space weather impacts. To explore the effects of satellite navigation failure on flight operation, we conduct this looking-forward study and propose solution methods from the standpoint of Air Traffic Management, by simulating satellite navigation failure scenarios. Based on the projected flight volume in 2025 related to the GBA airports, simulation results show that the economic costs can be tens of millions of Euros, which is dependent on the duration of satellite navigation failure and the time interval of ground navigation-based landing. We believe that this study can be a benchmark for evaluating the potential economic effects of forthcoming space weather on flight operations.
{"title":"Forward-Looking Study of Solar Maximum Impact in 2025: Effects of Satellite Navigation Failure on Aviation Network Operation in the Greater Bay Area, China","authors":"Dabin Xue, Jian Yang, Zhizhao Liu, Wei Cong","doi":"10.1029/2023sw003678","DOIUrl":"https://doi.org/10.1029/2023sw003678","url":null,"abstract":"Satellite navigation based on the Global Navigation Satellite System can provide aircraft with more precise guidance and increase flight efficiency. However, severe space weather events can cause satellite navigation failure due to the dramatic increase in total electron content and irregularities in the ionosphere. Consequently, ground navigation has to be used to replace satellite navigation, increasing aircraft separation standards and reducing airspace capacity. As a result, numerous flights may be delayed or even canceled, incurring significant financial losses. The occurrence peak of space weather events generally coincides with the 11-year-cycle solar maximum, and 2025 is expected to be the upcoming solar maximum. The Greater Bay Area (GBA), located in the equatorial ionization anomaly region of China, is particularly vulnerable to space weather impacts. To explore the effects of satellite navigation failure on flight operation, we conduct this looking-forward study and propose solution methods from the standpoint of Air Traffic Management, by simulating satellite navigation failure scenarios. Based on the projected flight volume in 2025 related to the GBA airports, simulation results show that the economic costs can be tens of millions of Euros, which is dependent on the duration of satellite navigation failure and the time interval of ground navigation-based landing. We believe that this study can be a benchmark for evaluating the potential economic effects of forthcoming space weather on flight operations.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"27 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Energetic particles from space deposit their energies on the Earth's atmosphere and contribute to variations in the concentration of neutral components such as ozone which controls the atmospheric temperature balance. Comprehensive understandings of their global impact on the atmosphere require whole pictures of spatiotemporal ionization distributions due to them. We first attempt to evaluate and summarize the altitude profiles of ionization for the September 2017 space weather event with cutting-edge space-borne and ground-based observations of different types of particle inputs. In early September 2017, the Sun showed notable activity, including X-class flares and solar proton events. During this period, ground-based radar observations have confirmed atmospheric ionization events by energetic particle precipitations of solar flare X-rays, solar protons, and radiation belt electrons, the main sources of ionization into the Earth's atmosphere. We estimate the altitude profiles of the ionization rate by using the Particle and Heavy Ion Transport code System (PHITS) with the input of the particle fluxes obtained by satellites. The estimates are then compared with measurements of the ionization altitude, ionization intensity, and electron density by the radars in the polar region, such as the PANSY radar at Syowa Station and the EISCAT in Tromsø, Norway. We conclude that the PHITS simulation results reasonably reproduce (within the error of a factor of two) those ionizations measured by ground-based instruments with inputs of observed ionization sources by satellites.
来自太空的高能粒子将其能量沉积在地球大气层中，造成臭氧等中性成分浓度的变化，从而控制大气温度平衡。要全面了解它们对大气层的全球影响，就需要了解它们造成的时空电离分布的全貌。我们首先尝试通过对不同类型粒子输入的前沿天基和地基观测，评估和总结 2017 年 9 月空间天气事件的电离高度剖面。2017 年 9 月初，太阳出现了显著的活动，包括 X 级耀斑和太阳质子事件。在此期间，地基雷达观测证实了由太阳耀斑 X 射线、太阳质子和辐射带电子等高能粒子沉淀引起的大气电离事件，它们是进入地球大气层的主要电离源。我们利用粒子和重离子传输代码系统（PHITS），并输入卫星获得的粒子通量，对电离率的高度分布进行了估算。然后，将估算结果与极地地区雷达（如 Syowa 站的 PANSY 雷达和挪威特罗姆瑟的 EISCAT）对电离高度、电离强度和电子密度的测量结果进行比较。我们的结论是，PHITS 模拟结果合理地再现了地面仪器测量到的电离情况（误差在 2 倍以内），并输入了卫星观测到的电离源。
{"title":"Atmospheric Ionizations by Solar X-Rays, Solar Protons, and Radiation Belt Electrons in September 2017 Space Weather Event","authors":"Kiyoka Murase, Ryuho Kataoka, Takanori Nishiyama, Kaoru Sato, Masaki Tsutsumi, Yoshimasa Tanaka, Yasunobu Ogawa, Tatsuhiko Sato","doi":"10.1029/2023sw003651","DOIUrl":"https://doi.org/10.1029/2023sw003651","url":null,"abstract":"Energetic particles from space deposit their energies on the Earth's atmosphere and contribute to variations in the concentration of neutral components such as ozone which controls the atmospheric temperature balance. Comprehensive understandings of their global impact on the atmosphere require whole pictures of spatiotemporal ionization distributions due to them. We first attempt to evaluate and summarize the altitude profiles of ionization for the September 2017 space weather event with cutting-edge space-borne and ground-based observations of different types of particle inputs. In early September 2017, the Sun showed notable activity, including X-class flares and solar proton events. During this period, ground-based radar observations have confirmed atmospheric ionization events by energetic particle precipitations of solar flare X-rays, solar protons, and radiation belt electrons, the main sources of ionization into the Earth's atmosphere. We estimate the altitude profiles of the ionization rate by using the Particle and Heavy Ion Transport code System (PHITS) with the input of the particle fluxes obtained by satellites. The estimates are then compared with measurements of the ionization altitude, ionization intensity, and electron density by the radars in the polar region, such as the PANSY radar at Syowa Station and the EISCAT in Tromsø, Norway. We conclude that the PHITS simulation results reasonably reproduce (within the error of a factor of two) those ionizations measured by ground-based instruments with inputs of observed ionization sources by satellites.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"37 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139057710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Lanabere, A. P. Dimmock, L. Rosenqvist, L. Juusola, A. Viljanen, A. Johlander, E. Odelstad
Geomagnetic storms can produce large perturbations on the Earth magnetic field. Through complex magnetosphere-ionosphere coupling, the geoelectric field (E) and geomagnetic field (B) are highly perturbed. The E is the physical driver of geomagnetically induced currents. However, a statistical study of the E in Sweden has never been done before. We combined geomagnetic data from the International Monitor for Auroral Geomagnetic Effects network in Northern Europe with a 3-D structure of Earth's electrical conductivity in Sweden as the input of a 1-D model to compute the E between 2000 and 2018. Northwestern Sweden presents statistically larger E magnitudes due to larger |dB/dt| variations in the north than in the south of Sweden and relative lower conductivity in the west compared to central and eastern Sweden. In contrast, the 15 strongest daily maximum |E| events present more frequently a maximum magnitude in central Sweden (62.25°N) and their relative strengths are not the same for all latitudes. These results highlight the different regional response to geomagnetic storms, which can be related to ground conductivity variability and the complex magnetosphere-ionosphere coupling mechanisms.
地磁暴会对地球磁场产生巨大的扰动。通过复杂的磁层-电离层耦合，地电场（E）和地磁场（B）受到高度扰动。地电场是地磁感应电流的物理驱动力。然而，瑞典从未对 E 进行过统计研究。我们将北欧极光地磁效应国际监测网的地磁数据与瑞典地球电导率的三维结构相结合，作为一维模型的输入，计算了 2000 年至 2018 年间的 E。与瑞典中部和东部相比，由于瑞典北部的 |dB/dt| 变化比南部大，且西部的电导率相对较低，因此瑞典西北部的 E 值在统计上较大。与此相反，15 个最强的日最大 E 事件中，瑞典中部（北纬 62.25°）出现最大 E 幅值的频率更高，而且各纬度的相对强度也不尽相同。这些结果突显了各地区对地磁暴的不同反应，这可能与地面传导性变化和复杂的磁层-电离层耦合机制有关。
{"title":"Analysis of the Geoelectric Field in Sweden Over Solar Cycles 23 and 24: Spatial and Temporal Variability During Strong GIC Events","authors":"V. Lanabere, A. P. Dimmock, L. Rosenqvist, L. Juusola, A. Viljanen, A. Johlander, E. Odelstad","doi":"10.1029/2023sw003588","DOIUrl":"https://doi.org/10.1029/2023sw003588","url":null,"abstract":"Geomagnetic storms can produce large perturbations on the Earth magnetic field. Through complex magnetosphere-ionosphere coupling, the geoelectric field (<b>E</b>) and geomagnetic field (<b>B</b>) are highly perturbed. The <b>E</b> is the physical driver of geomagnetically induced currents. However, a statistical study of the <b>E</b> in Sweden has never been done before. We combined geomagnetic data from the International Monitor for Auroral Geomagnetic Effects network in Northern Europe with a 3-D structure of Earth's electrical conductivity in Sweden as the input of a 1-D model to compute the <b>E</b> between 2000 and 2018. Northwestern Sweden presents statistically larger <b>E</b> magnitudes due to larger |<i>d</i><b>B</b>/<i>dt</i>| variations in the north than in the south of Sweden and relative lower conductivity in the west compared to central and eastern Sweden. In contrast, the 15 strongest daily maximum |<b>E</b>| events present more frequently a maximum magnitude in central Sweden (62.25°N) and their relative strengths are not the same for all latitudes. These results highlight the different regional response to geomagnetic storms, which can be related to ground conductivity variability and the complex magnetosphere-ionosphere coupling mechanisms.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"2 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Peak electron density data derived from GOLD measurements during 2018–2022 are used to analyze the magnitudes and correlations of ionospheric diurnal variability at low latitudes. The correlation distance describes the correlations between spatial locations and is defined in this paper as the angular separation at which the correlation coefficient decreases from 1 to 0.7. Variations in correlation distance with local time, season, magnetic latitude, solar activity, and geomagnetic activity are discussed in this study. The average value of the zonal correlation distance is approximately 8.55° and 3.56° for the meridional direction at low geomagnetic latitudes (magnetic latitudes <30°). The statistical results indicate that both zonal and meridional correlation distances vary little with local time premidnight, while they show pronounced seasonal and latitudinal variations. Both zonal and meridional correlation distances increase with increasing solar activity and decrease with enhancing geomagnetic activity. The EIA strength and gradient mainly modulate the distributions of correlation distances related to magnetic latitude, season, and solar flux level. An empirical model is constructed to describe the temporal and spatial variations in the correlation distance at low latitudes. The study of correlation distances would contribute to a better understanding of ionospheric variability and improvements in data assimilation.
{"title":"Horizontal Spatial Correlation of the Ionospheric Day-To-Day Variations at Low Latitudes Based on GOLD Nmax Data","authors":"Jiawen Chen, Jiahao Zhong, Yongqiang Hao, Xin Wan, Qiaoling Li, Zijing Tang, Xingyan Song, Hao Han, Kang Wang, Jiawei Kuai, Aojun Ren","doi":"10.1029/2023sw003627","DOIUrl":"https://doi.org/10.1029/2023sw003627","url":null,"abstract":"Peak electron density data derived from GOLD measurements during 2018–2022 are used to analyze the magnitudes and correlations of ionospheric diurnal variability at low latitudes. The correlation distance describes the correlations between spatial locations and is defined in this paper as the angular separation at which the correlation coefficient decreases from 1 to 0.7. Variations in correlation distance with local time, season, magnetic latitude, solar activity, and geomagnetic activity are discussed in this study. The average value of the zonal correlation distance is approximately 8.55° and 3.56° for the meridional direction at low geomagnetic latitudes (magnetic latitudes <30°). The statistical results indicate that both zonal and meridional correlation distances vary little with local time premidnight, while they show pronounced seasonal and latitudinal variations. Both zonal and meridional correlation distances increase with increasing solar activity and decrease with enhancing geomagnetic activity. The EIA strength and gradient mainly modulate the distributions of correlation distances related to magnetic latitude, season, and solar flux level. An empirical model is constructed to describe the temporal and spatial variations in the correlation distance at low latitudes. The study of correlation distances would contribute to a better understanding of ionospheric variability and improvements in data assimilation.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"76 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Steven K. Morley, Vania K. Jordanova, Yihua Zheng, Maksym Petrenko
The Ring current–Atmosphere interactions Model (RAM) with Self-Consistent magnetic (B) field (SCB) combines a large-scale kinetic model of ring current plasma with a three-dimensional (3-D) force-balanced model of the terrestrial magnetic field. RAM-SCB simulates the evolution of major ion species (H+, O+, and He+ by default) and electrons as a function of azimuth, radial distance, energy, and pitch angle. Simulation outputs include the Dst index, and pressure and differential flux of the modeled species, thus providing benefit as a science code and to inform surface charging hazard within the model domain. Version 2.2 of this open-source simulation code has now—as of 8 August 2023—been made available for Runs-On-Request via the Community Coordinated Modeling Center.
{"title":"RAM-SCB Runs on Request at CCMC","authors":"Steven K. Morley, Vania K. Jordanova, Yihua Zheng, Maksym Petrenko","doi":"10.1029/2023sw003771","DOIUrl":"https://doi.org/10.1029/2023sw003771","url":null,"abstract":"The Ring current–Atmosphere interactions Model (RAM) with Self-Consistent magnetic (B) field (SCB) combines a large-scale kinetic model of ring current plasma with a three-dimensional (3-D) force-balanced model of the terrestrial magnetic field. RAM-SCB simulates the evolution of major ion species (H<sup>+</sup>, O<sup>+</sup>, and He<sup>+</sup> by default) and electrons as a function of azimuth, radial distance, energy, and pitch angle. Simulation outputs include the Dst index, and pressure and differential flux of the modeled species, thus providing benefit as a science code and to inform surface charging hazard within the model domain. Version 2.2 of this open-source simulation code has now—as of 8 August 2023—been made available for Runs-On-Request via the Community Coordinated Modeling Center.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"71 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139055414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tim Divett, Malcolm Ingham, Gemma Richardson, Mark Sigley, Craig J. Rodger
Gas pipelines can experience elevated pipe to soil potentials (PSPs) during geomagnetic disturbances due to the induced geoelectric field. Gas pipeline operators use cathodic protection to keep PSPs between −0.85 and −1.2 V to prevent corrosion of the steel pipes and disbondment of the protective coating from the pipes. We have developed a model of the gas pipelines in the North Island of New Zealand to identify whether a hazard exists to these pipelines and how big this hazard is. We used a transmission line representation to model the pipelines and a nodal admittance matrix method to calculate the PSPs at nodes up to 5 km apart along the pipelines. We used this model to calculate PSPs resulting from an idealized 100 mVkm−1 electric field, initially to the north and east. The calculated PSPs are highest are at the ends of the pipelines in the direction of the applied electric field vector. The calculated PSP follows a characteristic curve along the length of the pipelines that matches theory, with deviations due to branchlines and changes in pipeline direction. The modeling shows that the PSP magnitudes are sensitive to the branchline coating conductance with higher coating conductances decreasing the PSPs at most locations. Enhanced PSPs produce the highest risk of disbondment and corrosion occurring, and hence this modeling provides insights into the network locations most at risk.
{"title":"Modeling Pipe to Soil Potentials From Geomagnetic Storms in Gas Pipelines in New Zealand","authors":"Tim Divett, Malcolm Ingham, Gemma Richardson, Mark Sigley, Craig J. Rodger","doi":"10.1029/2023sw003601","DOIUrl":"https://doi.org/10.1029/2023sw003601","url":null,"abstract":"Gas pipelines can experience elevated pipe to soil potentials (PSPs) during geomagnetic disturbances due to the induced geoelectric field. Gas pipeline operators use cathodic protection to keep PSPs between −0.85 and −1.2 V to prevent corrosion of the steel pipes and disbondment of the protective coating from the pipes. We have developed a model of the gas pipelines in the North Island of New Zealand to identify whether a hazard exists to these pipelines and how big this hazard is. We used a transmission line representation to model the pipelines and a nodal admittance matrix method to calculate the PSPs at nodes up to 5 km apart along the pipelines. We used this model to calculate PSPs resulting from an idealized 100 mVkm<sup>−1</sup> electric field, initially to the north and east. The calculated PSPs are highest are at the ends of the pipelines in the direction of the applied electric field vector. The calculated PSP follows a characteristic curve along the length of the pipelines that matches theory, with deviations due to branchlines and changes in pipeline direction. The modeling shows that the PSP magnitudes are sensitive to the branchline coating conductance with higher coating conductances decreasing the PSPs at most locations. Enhanced PSPs produce the highest risk of disbondment and corrosion occurring, and hence this modeling provides insights into the network locations most at risk.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"15 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138824138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Harada, Y. Nakamura, B. Sánchez-Cano, M. Lester, N. Terada, F. Leblanc
Characterization, understanding, and prediction of the Martian radio environment are of increasing importance to the forthcoming human exploration of Mars. Here we investigate 3–5 MHz radio absorption in the nightside ionosphere of Mars caused by enhanced ionization at <100 km altitudes during solar energetic particle (SEP) events. We conduct a quantitative analysis of radio absorption and SEP flux data that have been accumulated by two spacecraft currently orbiting Mars, thereby demonstrating that radio absorption is clearly correlated with SEP fluxes. A comparison of the observations with radio absorption properties predicted by a numerical model indicates that the relative temporal changes, radio frequency dependence, and SEP energy dependence of the observed radio absorption are in agreement with the model prediction. Meanwhile, the model systematically overestimates the radio absorption in the ionosphere by a factor of 3.7. We explore several sources of uncertainty, including the electron-neutral collision frequency, absolute sensitivity of the SEP instrument, and limited transport of SEPs to the atmosphere, but the ultimate cause of the systematic discrepancy between the measured and modeled radio absorption is yet to be identified. Further efforts should be put into the development of a comprehensive and observationally validated model of radio absorption in the Martian ionosphere to assist the future crew and spacecraft activities on the surface of Mars.
{"title":"Radio Absorption in the Nightside Ionosphere of Mars During Solar Energetic Particle Events","authors":"Y. Harada, Y. Nakamura, B. Sánchez-Cano, M. Lester, N. Terada, F. Leblanc","doi":"10.1029/2023sw003755","DOIUrl":"https://doi.org/10.1029/2023sw003755","url":null,"abstract":"Characterization, understanding, and prediction of the Martian radio environment are of increasing importance to the forthcoming human exploration of Mars. Here we investigate 3–5 MHz radio absorption in the nightside ionosphere of Mars caused by enhanced ionization at <100 km altitudes during solar energetic particle (SEP) events. We conduct a quantitative analysis of radio absorption and SEP flux data that have been accumulated by two spacecraft currently orbiting Mars, thereby demonstrating that radio absorption is clearly correlated with SEP fluxes. A comparison of the observations with radio absorption properties predicted by a numerical model indicates that the relative temporal changes, radio frequency dependence, and SEP energy dependence of the observed radio absorption are in agreement with the model prediction. Meanwhile, the model systematically overestimates the radio absorption in the ionosphere by a factor of 3.7. We explore several sources of uncertainty, including the electron-neutral collision frequency, absolute sensitivity of the SEP instrument, and limited transport of SEPs to the atmosphere, but the ultimate cause of the systematic discrepancy between the measured and modeled radio absorption is yet to be identified. Further efforts should be put into the development of a comprehensive and observationally validated model of radio absorption in the Martian ionosphere to assist the future crew and spacecraft activities on the surface of Mars.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"1 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138824204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We model the electron density in the topside of the ionosphere with an improved machine learning (ML) model and compare it to existing empirical models, specifically the International Reference Ionosphere (IRI) and the Empirical-Canadian High Arctic Ionospheric Model (E-CHAIM). In prior work, an artificial neural network (NN) was developed and trained on two solar cycles worth of Defense Meteorological Satellite Program data (113 satellite-years), along with global drivers and indices to predict topside electron density. In this paper, we highlight improvements made to this NN, and present a detailed comparison of the new model to E-CHAIM and IRI as a function of location, geomagnetic condition, time of year, and solar local time. We discuss precision and accuracy metrics to better understand model strengths and weaknesses. The updated neural network shows improved mid-latitude performance with absolute errors lower than the IRI by 2.5 × 109 to 2.5 × 1010 e−/m3, modestly improved performance in disturbed geomagnetic conditions with absolute errors reduced by about 2.5 × 109 e−/m3 at high Kp compared to the IRI, and high Kp percentage errors reduced by >50% when compared to E-CHAIM.
我们用改进的机器学习（ML）模型来模拟电离层顶部的电子密度，并将其与现有的经验模型，特别是国际参考电离层（IRI）和经验-加拿大北极高电离层模型（E-CHAIM）进行比较。在之前的工作中，我们开发了一个人工神经网络（NN），并根据两个太阳周期的国防气象卫星计划数据（113 个卫星年）以及全球驱动因素和指数对其进行了训练，以预测顶部电子密度。在本文中，我们将重点介绍对 NN 所做的改进，并详细比较新模型与 E-CHAIM 和 IRI 在位置、地磁条件、年度时间和太阳当地时间方面的函数关系。我们讨论了精度和准确度指标，以更好地了解模型的优缺点。更新后的神经网络改善了中纬度的性能，绝对误差比 IRI 低 2.5 × 109 到 2.5 × 1010 e-/m3，在干扰地磁条件下的性能略有改善，与 IRI 相比，在高 Kp 时绝对误差减少了约 2.5 × 109 e-/m3，与 E-CHAIM 相比，高 Kp 百分比误差减少了 50%。
{"title":"Topside Electron Density Modeling Using Neural Network and Empirical Model Predictions","authors":"S. Dutta, M. B. Cohen","doi":"10.1029/2023sw003501","DOIUrl":"https://doi.org/10.1029/2023sw003501","url":null,"abstract":"We model the electron density in the topside of the ionosphere with an improved machine learning (ML) model and compare it to existing empirical models, specifically the International Reference Ionosphere (IRI) and the Empirical-Canadian High Arctic Ionospheric Model (E-CHAIM). In prior work, an artificial neural network (NN) was developed and trained on two solar cycles worth of Defense Meteorological Satellite Program data (113 satellite-years), along with global drivers and indices to predict topside electron density. In this paper, we highlight improvements made to this NN, and present a detailed comparison of the new model to E-CHAIM and IRI as a function of location, geomagnetic condition, time of year, and solar local time. We discuss precision and accuracy metrics to better understand model strengths and weaknesses. The updated neural network shows improved mid-latitude performance with absolute errors lower than the IRI by 2.5 × 10<sup>9</sup> to 2.5 × 10<sup>10</sup> e<sup>−</sup>/m<sup>3</sup>, modestly improved performance in disturbed geomagnetic conditions with absolute errors reduced by about 2.5 × 10<sup>9</sup> e<sup>−</sup>/m<sup>3</sup> at high Kp compared to the IRI, and high Kp percentage errors reduced by >50% when compared to E-CHAIM.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"40 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139029985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brett A. Carter, Noé Lugaz, Steven K. Morley, Jennifer Gannon, Shasha Zou, Huixin Liu
The media interest/coverage of space weather has been increasing as we approach solar maximum and the private space industry has grown significantly since the last significant solar maximum in 2000–2002. It is not uncommon for space weather media coverage to use hyperbole with frequent references to the infamous “Carrington event.” The implications of associating each of the many upcoming moderate-to-severe storms with the Carrington event are discussed, and we encourage the curbing of hyperbole whenever possible. While there is an excellent but small cohort of space weather researchers actively engaging with the media, we urge more (particularly early-to-mid career) to take advantage of media training resources and to join in. We also call for these efforts to be broadly supported by peers and institutions for the benefit of space weather as a discipline.
{"title":"Space Weather in the Popular Media, and the Opportunities the Upcoming Solar Maximum Brings","authors":"Brett A. Carter, Noé Lugaz, Steven K. Morley, Jennifer Gannon, Shasha Zou, Huixin Liu","doi":"10.1029/2023sw003819","DOIUrl":"https://doi.org/10.1029/2023sw003819","url":null,"abstract":"The media interest/coverage of space weather has been increasing as we approach solar maximum and the private space industry has grown significantly since the last significant solar maximum in 2000–2002. It is not uncommon for space weather media coverage to use hyperbole with frequent references to the infamous “Carrington event.” The implications of associating each of the many upcoming moderate-to-severe storms with the Carrington event are discussed, and we encourage the curbing of hyperbole whenever possible. While there is an excellent but small cohort of space weather researchers actively engaging with the media, we urge more (particularly early-to-mid career) to take advantage of media training resources and to join in. We also call for these efforts to be broadly supported by peers and institutions for the benefit of space weather as a discipline.","PeriodicalId":22181,"journal":{"name":"Space Weather","volume":"34 3 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138715534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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