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Extreme space weather events caused by super active regions during solar cycles 21-24

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Research in Astronomy and Astrophysics 2021年第5期21卷 296-300,302页

作者： Gui-Ming Le Gui-Ang Liu Ming-Xian Zhao Tian Mao Ping-Guo Xu School of Physics Science&Technology Lingnan Normal UniversityZhanjiang 524048China Key laboratory of space weather National Center for Space WeatherChina Meteorological AdministrationBeijing 100081China Beijing Engineering Research Center of Smart Mechanical Innovation Design Service Beijing 100020China

Extreme space weather events including≥X5.0 flares,ground level enhancement(GLE)events and super geomagnetic storms(Dst≥-250 nT)caused by super active regions(SARs)during solar cycles 21-24 were *** total number ofX5.0 solar flares was 62,among which 41 were X5.0-X9.9 flares and 21 were≥X10.0 *** found that 83.9%of the≥X5.0 flares were produced by SARs;78.05%of the X5.0-X9.9 and 95.24%of the≥X10.0 solar flares were produced by SARs;46 GLEs were registered during solar cycles 21-24,and 25 GLEs were caused by SARs,indicating that 54.3%of the GLEs were caused by SARs;24 super geomagnetic storms were recorded during solar cycles 21-24,and 12 of them were caused by SARs,namely 50%of the super geomagnetic storms were caused by *** ascertained that only 29 SARs produced≥X5.0 flares,15 SARs generated GLEs and 10 SARs triggered super geomagnetic *** the 51 SARs,only 33 SARs produced at least one extreme space weather event,while none of the other 18 SARs could trigger an extreme space weather *** were only four SARs and each of them generated not only a≥X5.0 flare,but also a GLE event and a super geomagnetic *** of the extreme space weather events caused by the SARs appeared during solar cycles 22 and 23,especially for GLE events and super geomagnetic *** longitudinal distributions of source locations for the extreme space weather events caused by SARs were also studied.

关键词： Sun:sunspots Sun:flares Sun:particle emission Sun:solar-terrestrial relations

Automatic Generation of Artificial space weather Forecast Product Based on Sequence-to-sequence Model

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空间科学学报 2024年第1期44卷 80-94页

作者：罗冠霆 ZOU Yenan CAI Yanxia State Key laboratory of space weather National Space Science CenterChinese Academy of SciencesBeijing 100190 University of Chinese Academy of Sciences Beijing 100049 Key laboratory of Science and Technology on Environment space Situation Awareness Chinese Academy of SciencesBeijing 100190

Both analyzing a large amount of space weather observed data and alleviating personal experience bias are significant challenges in generating artificial space weather forecast *** the use of natural language generation methods based on the sequence-to-sequence model,space weather forecast texts can be automatically *** conduct our generation tasks at a fine-grained level,a taxonomy of space weather phenomena based on descriptions is ***,our MDH(Multi-Domain Hybrid)model is proposed for generating space weather summaries in two *** model is composed of three sequence-to-sequence-based deep neural network sub-models(one Bidirectional Auto-Regressive Transformers pre-trained model and two Transformer models).Then,to evaluate how well MDH performs,quality evaluation metrics based on two prevalent automatic metrics and our innovative human metric are *** comprehensive scores of the three summaries generating tasks on testing datasets are 70.87,93.50,and 92.69,*** results suggest that MDH can generate space weather summaries with high accuracy and coherence,as well as suitable length,which can assist forecasters in generating high-quality space weather forecast products,despite the data being starved.

关键词： space weather Deep learning Data-to-text Natural language generation

Image Feature Extraction and Matching of Augmented Solar Images in space weather

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空间科学学报 2023年第5期43卷 840-852页

作者： WANG Rui BAO Lili CAI Yanxia State Key laboratory of space weather National Space Science CenterChinese Academy of SciencesBeijing 100190 University of Chinese Academy of Sciences Beijing 100049 Key laboratory of Science and Technology on Environment space Situation Awareness Chinese Academy of SciencesBeijing 100190

Augmented solar images were used to research the adaptability of four representative image extraction and matching algorithms in space weather *** include the scale-invariant feature transform algorithm,speeded-up robust features algorithm,binary robust invariant scalable keypoints algorithm,and oriented fast and rotated brief *** performance of these algorithms was estimated in terms of matching accuracy,feature point richness,and running *** experiment result showed that no algorithm achieved high accuracy while keeping low running time,and all algorithms are not suitable for image feature extraction and matching of augmented solar *** solve this problem,an improved method was proposed by using two-frame matching to utilize the accuracy advantage of the scale-invariant feature transform algorithm and the speed advantage of the oriented fast and rotated brief ***,our method and the four representative algorithms were applied to augmented solar *** application experiments proved that our method achieved a similar high recognition rate to the scale-invariant feature transform algorithm which is significantly higher than other *** method also obtained a similar low running time to the oriented fast and rotated brief algorithm,which is significantly lower than other algorithms.

关键词： Augmented reality Augmented image Image feature point extraction and matching space weather Solar image

Observations of the first meteorological rocket of the Meridian space weather Monitoring Project

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Chinese Science Bulletin 2011年第20期56卷 2131-2137页

作者： JIANG GuoYing XU JiYao SHI DongBo WEI Feng WANG LianZhong State Key laboratory of space weather Center for Space Science and Applied ResearchChinese Academy of SciencesBeijing 100190China Rocket and Balloon Sounding Center for Space Science and Applied ResearchChinese Academy of SciencesBeijing 100190China

On June 3,2010,the first meteorological rocket of the Meridian space weather Monitoring Project was successfully launched at the Hainan rocket launch site(19.5°N),*** paper analyzes the vertical profiles of atmospheric temperature and wind recorded by the rocket and its supportive balloons,and investigates wind shear,gravity waves and atmospheric *** addition,we compare the vertical profiles of atmospheric temperature and wind with SABER/TIMED temperature measurements and the modeling results of MSIS00 and HWM07.

关键词：空间天气监测气象火箭经络大气温度垂直剖面火箭发射场大气稳定性 SABER

Ensemble Numerical Simulations of Realistic SEP Events and the Inspiration for space weather Awareness

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Research in Astronomy and Astrophysics 2022年第2期22卷 29-44页

作者： Chenxi Du Xianzhi Ao Bingxian Luo Jingjing Wang Chong Chen Xin Xiong Xin Wang Gang Li National space Science Center Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Key laboratory of Science and Technology on Environmental space Situation Awareness Chinese Academy of SciencesBeijing 100190China State Key laboratory of space weather National Space Science CenterChinese Academy of SciencesBeijing 100190China School of space and Environment Beihang UniversityBeijing 100190China Department of space Sciences University of Alabama in HuntsvilleAL 35899United States of America

The solar energetic particle(SEP)event is a kind of hazardous space weather phenomena,so its quantitative forecast is of great importance from the aspect of space environmental situation *** present here a set of SEP forecast tools,which consists of three components:(1)a simple polytropic solar wind model to estimate the background solar wind conditions at the inner boundary of 0.1 AU(about 20 R⊙);(2)an ice-cream-cone model to estimate the erupted coronal mass ejection(CME)parameters;and(3)the improved Particle Acceleration and Transport in the Heliosphere(i PATH)model to calculate particle fluxes and energy *** utilizing the above models,we have simulated six realistic SEP events from 2010 August 14 to 2014 September 10,and compared the simulated results to the Geostationary Operational Environmental Satellites(GOES)spacecraft *** results show that the simulated fluxes of>10 Me V particles agree with the observations while the simulated fluxes of>100 Me V particles are higher than the observed *** of the possible reasons is that we have adopted a simple method in the model to calculate the injection rate of energetic ***,we have conducted the ensemble numerical simulations over these events and investigated the effects of different background solar wind conditions at the inner boundary on SEP *** results imply that the initial CME density plays an important role in determining the power spectrum,while the effect of varying background solar wind temperature is not ***,we have examined the influence of CME initial density on the numerical prediction results for virtual SEP cases with different CME ejection *** result shows that the effect of initial CME density variation is inversely associated with CME speed.

关键词： Sun:coronal mass ejections(CMEs) Sun:particle emission acceleration of particles shock waves methods:numerical

Magnetic reconnection structures in the boundary layer of an interplanetary magnetic cloud

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Science China(Technological Sciences) 2004年第1期47卷 6-14页

作者： WEI Fengsi LIU Rui FENG Xueshang ZHONG Dingkun YANG Fang Key laboratory for space weather Chinese Academy of Sciences Beijing 100080 China Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China

An interplanetary magnetic diffusion region was detected by WIND during 0735-0850 UT on May 15, 1997 when the front boundary layer of a magnetic cloud passed through the spacecraft about 190 earth radii upstream of the earth. The main signals of magnetic reconnection processes are: (i) Flow reversal was detected at about 0810 UT. The counter-streaming flows have the speeds of about 65 and 41 km/s, respectively, with an angle of about 140 degree between them. (ii) Hall magnetic field was detected. The Hall fields ?By and +By, perpendicular to the X-Z plane, with their magnitude up to ～7.0 nT, are superposed upon a guide field about 12 nT. (iii) Alfvenic fluctuations are obviously intensified inside the reconnection region; at the front boundary of the reconnection region, a slow-mode-like discontinuity was detected. (iv) Ions are heated intensively inside the reconnection region, with their temperature three times higher than that ahead of the boundary layer; electrons are also heated, with a little enhancement in their temperature. The above observations indicate that magnetic reconnection processes could take place in interplanetary space. Keywords solar wind - interplanetary magnetic clouds - magnetic reconnection

关键词： solar wind, interplanetary magnetic clouds, magnetic reconnection.

A study on the dynamic spectral indices for SEP events on 2000 July 14 and 2005 January 20

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Research in Astronomy and Astrophysics 2020年第3期20卷 129-135页

作者： Ming-Xian Zhao Gui-Ming Le Key laboratory of space weather National Center for Space WeatherChina Meteorological Administration.Beijing 100081China

We have studied the dynamic proton spectra for the two solar energetic particle(SEP)events on2000 July 14(hereafter GLE59)and 2005 January 20(hereafter GLE69).The source locations of GLE59 and GLE69 are N22 W07 and N12 W58 *** fluxes>30 Me V have been used to compute the dynamic spectral indices of the two SEP *** results show that spectral indices of the two SEP events increased more swiftly at early times,suggesting that the proton fluxes>30 Me V might be accelerated particularly by the concurrent flares at early times for the two SEP *** the GLE69 with source location at N12 W58,both flare site and shock nose are well connected with the Earth at the earliest ***,only the particles accelerated by the shock driven by eastern flank of the CME can propagate along the interplanetary magnetic field line to the Earth after the *** the GLE59 with source location at N22 W07,only the particles accelerated by the shock driven by western flank of the associated CME can reach the Earth after the *** results also show that there was slightly more than one hour during which the proton spectra for GLE69 are softer than that for GLE59 after the flares,suggesting that the shock driven by eastern flank of the CME associated with GLE69 is weaker than the shock driven by the western flank of the CME associated with *** results support that quasi-perpendicular shock has stronger potential in accelerating particles than the quasi-parallel *** results also suggest that only a small part of the shock driven by western flank of the CME associated with the GLE59 is quasi-perpendicular.

关键词： Sun:flares-Sun coronal mass ejections(CMEs)-Sun particle emission-Sun solarterrestrial relations

Large scale current systems developed from substorm onset:Global MHD results

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Science China(Technological Sciences) 2018年第3期61卷 389-396页

作者： TANG BinBin WANG Chi State Key laboratory of space weather National Space Science Center Chinese Academy of Sciences

We investigate the large-scale substorm current systems developed from its onset in an idealized substorm event simulated by global magnetohydrodynamic(MHD) models. Mainly three current systems(loops) are revealed:(1) the classical substorm current wedge, which is composed by the disputed cross-tail current in the magnetotail, the nightside westward electrojet in the high-latitude ionosphere and a pair of region 1 field-aligned currents(FAC);(2) the partial-ring current system, which is braced by two region 2 FACs; and(3) the meridional current system, which is formed by an equatorial radial current(outward/inward in the morning/evening sector), and region 1 and region 2 FACs at its two ends. The region 2 FAC connects with region 1 FAC by a latitudinal horizontal current at each morning/evening ionosphere to complete Loops 2 and 3. A quantitative study shows the significant enhancement of these current systems during the substorm expansion phase, while Loop 1 dominates, which can reach a magnitude of ~1 MA. Empirical relations among the ionospheric currents and the related magnetotail currents are established based on the simulation results, implying that the substonn current systems are not evolved locally or separately, but must be viewed from a global perspective. This knowledge of large-scale substorm current system would deepen our understanding of the substorm development and could be validated by observations in the future.

关键词： magnetospheric physics substorm current system magnetohydrodynamic(MHD) simulation

GPU-accelerated computing of three-dimensional solar wind background

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Science China Earth Sciences 2013年第11期56卷 1864-1880页

作者： FENG XueShang ZHONG DingKun XIANG ChangQing ZHANG Yao SIGMA weather Group State Key Laboratory for Space Weather Center for Space Science and Applied ResearchChinese Academy of Sciences

High-performance computational models are required to make the real-time or faster than rea^-time numerical prediction of adverse space weather events and their influence on the geospace environment. The main objective in this article is to explore the application of programmable graphic processing units （GPUs） to the numerical space weather modeling for the study of solar wind background that is a crucial part in the numerical space weather modeling. GPU programming is realized for our Solar-Interplanetary-CESE MHD model （SIP-CESE MHD model） by numerically studying the solar corona/interplanetary so- lar wind. The global solar wind structures are obtained by the established GPU model with the magnetic field synoptic data as input. Meanwhile, the time-dependent solar surface boundary conditions derived from the method of characteristics and the mass flux limit are incorporated to couple the observation and the three-dimensional （3D） MHD model. The simulated evolu- tion of the global structures for two Carrington rotations 2058 and 2062 is compared with solar observations and solar wind measurements t^om spacecraft near the Earth. The MHD model is also validated by comparison with the standard potential field source surface （PFSS） model. Comparisons show that the MHD results are in good overall agreement with coronal and interplanetary structures, including the size and distribution of coronal holes, the position and shape of the streamer belts, and the transition of the solar wind speeds and magnetic field polarities.

关键词： space weather modeling SIP-CESE MHD model GPU computing