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Long-term Variation of the Solar Polar Magnetic Fields at Different Latitudes

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Research in Astronomy and Astrophysics 2024年第7期24卷 193-200页

作者： Shuhong Yang Jie Jiang Zifan Wang Yijun Hou Chunlan Jin Qiao Song Yukun Luo Ting Li Jun Zhang Yuzong Zhang Guiping Zhou Yuanyong Deng Jingxiu Wang national Astronomical Observatories Chinese Academy of Sciences School of Astronomy and space Science University of Chinese Academy of Sciences State Key Laboratory of Solar Activity and space Weather National Space Science CenterChinese Academy of Sciences School of space and Environment Beihang University Key Laboratory of space Weather National Satellite Meteorological Center (National Center for Space Weather) Innovation center for FengYun Meteorological Satellite (FYSIC) School of Physics and Materials Science Anhui University

The polar magnetic fields of the Sun play an important role in governing solar activity and powering fast solar wind. However, because our view of the Sun is limited in the ecliptic plane, the polar regions remain largely uncharted. Using the high spatial resolution and polarimetric precision vector magnetograms observed by Hinode from 2012 to 2021, we investigate the long-term variation of the magnetic fields in polar caps at different *** Hinode magnetic measurements show that the polarity reversal processes in the north and south polar caps are non-simultaneous. The variation of the averaged radial magnetic flux density reveals that, in each polar cap, the polarity reversal is completed successively from the 70° latitude to the pole, reflecting a poleward magnetic flux migration therein. These results clarify the polar magnetic polarity reversal process at different latitudes.

关键词： dynamo Sun: magnetic fields Sun: photosphere

Inversion of O_(2) 1.27 μm nightglow emissions: A climatological analysis using satellite Limb-Viewed spectra and Harmonic analysis method

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Earth and Planetary Physics 2024年第4期8卷 632-640页

作者： YiYi Sui YaJun Zhu QiuYu Chen MaoSheng He JiYao Xu State Key Laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100190China Key Laboratory of Solar Activity and space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Hainan national Field Science Observation and Research Observatory for space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China

This study employs a linear inversion algorithm to retrieve volume emission rates(VERs)of molecular O_(2) nightglow at 1.27μm,utilizing Limb-Viewed spectra obtained from the SCanning Imaging Absorption spectroMeter for Atmospheric for CHartographY(SCIAMACHY)payload on board the Envisat *** retrieved results are compared with VERs data from the SABER payload on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics(TIMED)satellite,exhibiting *** will help to facilitate accurate revelation of spatial distribution and periodic variation in O_(2) *** are extracted monthly within the altitude range of 75-110 km from 2002 to 2012,yielding a climatology of spatial and temporal *** meridional structure exhibits two maxima,at the equator and at 45°*** August and October,the VERs exhibit a meridional bimodal structure,with the weaker one above the equator and the stronger one above 45°*** April,the VERs reach their annual ***,harmonic analysis reveals significant temporal variations on different *** emission shows characteristics of annual and semi-annual variation,and a non-linear long-term trend associated with solar cycle activity.

关键词： VERs O_(2)1.27μm nightglow SCIAMACHY

Multi-path navigation method using solar panel-reflected solar oscillations for Earth satellites

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Science China(Information Sciences) 2024年第7期67卷 327-328页

作者： Yuqing YANG Haonan YANG Xiaolin NING Weiren WU Jiancheng FANG School of Instrument Science & Opto-electronics Engineering Beihang University Lunar Exploration and space Program center China National Space Administration

Several autonomous navigation methods have been studied to reduce reliance on the ground stations. Geomagnetic navigation, gravity gradient navigation, and celestial navigation using optical sensors are typical autonomous navigation methods. Geomagnetic and gravity gradient navigation have low navigation accuracy (1301 m [1] and 235 m [2], respectively) due to the poor accuracy of the geomagnetic and gravity gradient maps.

关键词： Solar panels

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Preface to the Special Issue on Modeling and Data Analysis Methods for the SMILE mission

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Earth and Planetary Physics 2024年第1期8卷 1-4页

作者： TianRan Sun Hyunju Connor Andrey Samsonov national space Science center Chinese Academy of SciencesBeijing 100190China NASA Goddard space Flight center US Mullard space Science Laboratory University College LondonUK

The SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)project(http://***/smile/,https://***/web/smile/mission)is a joint spacecraft mission of the European space Agency(ESA)and the Chinese Academy of Sciences(CAS)with an expected launch in *** aims to study the global interactions of solar wind–magnetosphere–ionosphere innovatively by imaging the Earth’s magnetosheath and cusps in soft X-rays and the northern auroral region in ultraviolet(UV)while simultaneously measuring plasma and magnetic field parameters in the solar wind and magnetosheath along a highly-elliptical and highly-inclined *** special issue is composed of 22 articles,presenting recent progress in modeling and data analysis techniques developed for the SMILE *** this preface,we categorize the articles into the following seven topics and provide brief summaries:(1)instrument descriptions of the Soft X-ray Imager(SXI),(2)numerical modeling of the X-ray signals,(3)data processing of the X-ray images,(4)boundary tracing methods from the simulated images,(5)physical phenomena and a mission concept related to the scientific goals of SMILE-SXI,(6)studies of the aurora,and(7)ground-based support for SMILE.

关键词： SMILE X-ray imaging magnetosphere auroral ionosphere

Study of factors influencing the occurrence rate of 60 Hz power line radiation in the topside ionosphere:A systematic survey using the CSES satellite

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Science China(Technological Sciences) 2024年第6期67卷 1879-1892页

作者： MA ZhenHui ZHAO ShuFan LIAO Li SHEN XuHui LU HengXin School of Emergency Management Science and Engineering University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing100190China Key Laboratory of Solar Activity and space Weather National Space Science CenterChinese Academy of SciencesBeijing100190China national Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing100085China Institute of Geophysics China Earthquake AdministrationBeijing100081China

We analyze the topside ionosphere power line radiation(PLR)at 60 Hz over the US using electric field data collected by CSES satellite between January 2019 and December *** study aimed to further investigate the month-to-month variation characteristic of PLR occurrence rate observed by satellite and its several influencing factors,including solar radiation,lightning activity,and try to clarify the influence of electricity *** results show that the solar radiation(solar zenith angle and F10.7)plays a major role in the variation of the PLR occurrence rate,and that there is no direct connection with the number of *** the relationship between PLR occurrence rate and electricity consumption,the low occurrence rate associated with decreased weekend electricity consumption was not observed in the ***,there is a significant difference in PLR occurrence rate between the East and West Coasts of the US at the same latitude during the same time period,suggesting that the significant difference in PLR occurrence rate is caused by the significant difference in electricity consumption between the two *** excluding the effect of solar radiation on PLR occurrence rate,we concluded that only a significant difference in regional electricity consumption could lead to a corresponding change in PLR occurrence rate detected by the Low-Earth-Orbit ***,we also found there is seasonal variation in the diurnal differences of the PLR occurrence rate caused by seasonal variation of the lower ionosphere.

关键词： CSES satellite power line radiation occurrence rate solar radiation lightning activity electricity consumption

Joint observations of the large-scale ULF wave activity from space to ground associated with the solar wind dynamic pressure enhancement

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Science China(Technological Sciences) 2024年第7期67卷 2215-2229页

作者： SUN XiaoYing HU YunPeng ZHIMA Zeren DUAN SuPing LV FangXian SHEN XuHui national Institute of Natural Hazards Ministry of Emergency ManagementBeijing 100085China School of space and Environment Beihang UniversityBeijing 102206China State Key Laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China

This study reports the rare ultralow-frequency(ULF) wave activity associated with the solar wind dynamic pressure enhancement that was successively observed by the GOES-17(Geostationary Operational Environmental Satellite) in the magnetosphere, the CSES(China Seismo-Electromagnetic Satellite) in the ionosphere, and the THEMIS ground-based observatories(GBO) GAKO and EAGL in the Earth's polar region during the main phase of an intense storm on 4 November 2021. Along with the enhanced-pressure solar wind moving tailward, the geomagnetic field structure experienced a large-scale change. From dawn/dusk sides to midnight, the GAKO, EAGL, and GOES-17 sequentially observed the ULF waves in a frequency range of0.04–0.36 Hz at L shells of ~5.07, 6.29, and 5.67, respectively. CSES also observed the ULF wave event with the same frequency ranges at wide L-shells of 2.52–6.22 in the nightside ionosphere. The analysis results show that the ULF waves at ionospheric altitude were mixed toroidal-poloidal mode waves. Comparing the ULF waves observed in different regions, we infer that the nightside ULF waves were directly or indirectly excited by the solar wind dynamic pressure increase: in the area of L-shells~2.52–6.29, the magnetic field line resonances(FLRs) driven by the solar wind dynamic pressure increase is an essential excitation source;on the other hand, around L~3.29, the ULF waves can also be excited by the outward expansion of the plasmapause owing to the decrease of the magnetospheric convection, and in the region of L-shells ~5.19–6.29, the ULF waves are also likely excited by the ion cyclotron instabilities driven by the solar wind dynamic pressure increase.

关键词： ultralow-frequency(ULF)wave solar wind dynamic pressure(P_(sw)) magnetic field line resonance(FLR) ion cyclotron instability

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Understanding the Low Predictability of the 2015/16 El Niño Event Based on a Deep Learning Model

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Advances in Atmospheric Sciences 2024年第7期41卷 1313-1325页

作者： Tingyu WANG Ping HUANG Xianke YANG center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China national space Science center Chinese Academy of SciencesBeijing 100190China State Key Laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China College of Plant Science and Technology Huazhong Agricultural UniversityWuhan 430070China

The 2015/16 El Niño event ranks among the top three of the last 100 years in terms of intensity,but most dynamical models had a relatively low prediction skill for this event before the summer ***,the attribution of this particular event can help us to understand the cause of super El Niño–Southern Oscillation events and how to forecast them *** present study applies attribute methods based on a deep learning model to study the key factors related to the formation of this event.A deep learning model is trained using historical simulations from 21 CMIP6 models to predict the Niño-3.4 *** integrated gradient method is then used to identify the key signals in the North Pacific that determine the evolution of the Niño-3.4 *** crucial signals are then masked in the initial conditions to verify their roles in the *** addition to confirming the key signals inducing the super El Niño event revealed in previous attribution studies,we identify the combined contribution of the tropical North Atlantic and the South Pacific oceans to the evolution and intensity of this event,emphasizing the crucial role of the interactions among them and the North *** approach is also applied to other El Niño events,revealing several new precursor *** study suggests that the deep learning method is useful in attributing the key factors inducing extreme tropical climate events.

关键词： ENSO attribution deep learning ENSO prediction extreme El Niño

Fast compressed sensing spectral measurement with adaptive gradient multiscale resolution

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Chinese Physics B 2024年第2期33卷 298-304页

作者：蓝若明刘雪峰李天平白成杰 School of Physics and Electronics Shandong Normal UniversityJinan 250014China Key Laboratory of Electronics and Information Technology for space Systems National Space Science CenterChinese Academy of SciencesBeijing 100190China

We propose a fast,adaptive multiscale resolution spectral measurement method based on compressed *** method can apply variable measurement resolution over the entire spectral range to reduce the measurement time by over 75%compared to a global high-resolution *** the characteristics of the human retina system,the resolution distribution follows the principle of gradually *** system allows the spectral peaks of interest to be captured dynamically or to be specified a priori by a *** system was tested by measuring single and dual spectral peaks,and the results of spectral peaks are consistent with those of global high-resolution measurements.

关键词： spectrometer compressed sensing adaptive gradient multiscale resolution fast measurement

A comparative study on kinetics and dynamics of two dump truck lifting mechanisms using MATLAB simscape

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 146-156页

作者： Thong Duc Hong Minh Quang Pham Son Cong Tran Lam Quang Tran Truong Thanh Nguyen Faculty of Transportation Engineering Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam vietnam national University Ho Chi Minh City(VNU-HCM) Ho Chi Minh City 700000Vietnam Industrial Maintenance Training center Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam

In this paper,two lifting mechanism models with opposing placements,which use the same hydraulic hoist model and have the same angle of 50°,have been *** mechanical and hydraulic simulation models are established using MATLAB Simscape to analyze their kinetics and dynamics in the lifting and holding *** simulation findings are compared to the analytical calculation results in the steady state,and both methods show good *** the early lifting stage,Model 1 produces greater force and discharges goods in the container faster than Model ***,Model 2 reaches a higher force and ejects goods from the container cleaner than its counterpart at the end lifting *** established simulation models can consider the effects of dynamic loads due to inertial moments and forces generated during the system *** is crucial in studying,designing,and optimizing the structure of hydraulic-mechanical systems.

关键词： Dump truck Lifting mechanism Hydraulic MATLAB Simscape Kinetic dynamic analysis