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Research in Astronomy and Astrophysics 2020年第1期20卷 27-34页

作者： Juan Miao Xin Wang Ting-Ling Ren Zhi-Tao Li National Space Science Center Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Predictions of the strength of solar cycles are important and are necessary for planning long-term missions.A new solar cycle 25 is coming soon,and the amplitude is needed for space weather operators.Some predictions have been made using different methods and the values are drastically different.However,since 2015 July 1,the original sunspot number data have been entirely replaced by the Version 2.0 data series,and the sunspot number values have changed greatly.In this paper,using Version 2 smoothed sunspot numbers and aa indices,we verify the predictions for cycles 18-24 based on Ohl’s Precursor Method.Then a similar-cycles method is used to evaluate the aa minimum of 9.7(±1.1)near the start of cycle 25 and based on the linear regression relationship between sunspot maxima and aa minima,our predicted Version 2maximum sunspot number for cycle 25 is 121.5(±32.9).

关键词： solar cycle sunspot geomagnetic aa indices

Statistical Study of the Geoeffectivity of Halo Coronal Mass Ejections Associated with X-Class Flares during solar cycles 23 and 24

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Open Journal of Applied Sciences 2024年第4期14卷 950-960页

作者： Younoussa Diakite Christian Zoundi M’Bi Kabore Jean Louis Zerbo Laboratoire de Chimie Analytique de Physique Spatiale et Energ&#233tique (L@CAPSE) Physics Department Universit&#233 Norbert Zongo Koudougou Burkina Faso Laboratoire de Maté riaux d&#8217H&#233liophysique et Environnement (LAMHE) Physics Department Universit&#233 Nazi Boni Bobo-Dioulasso Burkina Faso

By analysing a long series of data (1996-2019), we show that solar cycle 23 was more marked by violent solar flares and coronal mass ejections (CMEs) compared to solar cycle 24. In particular, the halo coronal mass ejections associated with X-class flares appear to be among the most energetic events in solar activity given the size of the flares, the speed of the CMEs and the intense geomagnetic storms they produce. Out of eighty-six (86) X-class halo CMEs, thirty-seven (37) or 43% are highly geoeffective;twenty-four (24) or approximately 28% are moderately geoeffective and twenty-five (25) or 29% are not geoeffective. Over the two solar cycles (1996 to 2019), 71% of storms were geoeffective and 29% were not. For solar cycle 23, about 78% of storms were geoeffective, while for solar cycle 24, about 56% were geoeffective. For the statistical study based on speed, 85 halo CMEs associated with X-class flares were selected because the CME of 6 December 2006 has no recorded speed value. For both solar cycles, 75.29% of the halo CMEs associated with X-class flares have a speed greater than 1000 km/s. The study showed that 42.18% of halo (X) CMEs with speeds above 1000 km/s could cause intense geomagnetic disturbances. These results show the contribution (in terms of speed) of each class of halo (X) CMEs to the perturbation of the Earth’s magnetic field. Coronal mass ejections then become one of the key indicators of solar activity, especially as they affect the Earth.

关键词： CME Halo (X) Geoeffectivity Geomagnetic Storm solar Flare solar cycle

Concept of the solar ring mission:An overview

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Science China(Technological Sciences) 2020年第9期63卷 1699-1713页

作者： WANG YuMing JI HaiSheng WANG YaMin XIA LiDong SHEN ChengLong GUO JingNan ZHANG QuanHao HUANG ZhengHua LIU Kai LI XiaoLei LIU Rui WANG JingXiu WANG Shui CAS Key Laboratory of Geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of China(USTC)Hefei230026China CAS Center for Excellence in Comparative Planetology USTCHefei230026China Purple Mountain Observatory Chinese Academy of SciencesNanjing210034China CAS Key Lab of Microsatellite Innovation Academy for MicrosatellitesChinese Academy of SciencesShanghai201203China Shanghai Engineering Center for Microsatellites Shanghai201203China Shandong Provincial Key Laboratory of Optical Astronomy and solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai264209China Univeristy of Chinese Academy of Sciences Beijing100049China

The concept of the solar Ring mission was gradually formed from L5/L4 mission concept, and the proposal of its pre-phase study was funded by the National Natural Science Foundation of China in November 2018 and then by the Strategic Priority Program of Chinese Academy of Sciences in space sciences in May 2019. solar Ring mission will be the first attempt to routinely monitor and study the Sun and inner heliosphere from a full 360-degree perspective in the ecliptic plane. The current preliminary design of the solar Ring mission is to deploy six spacecraft, grouped in three pairs, on a sub-AU orbit around the Sun. The two spacecraft in each group are separated by about 30?and every two groups by about 120?. This configuration with necessary science payloads will allow us to establish three unprecedented capabilities:(1) determine the photospheric vector magnetic field with unambiguity,(2) provide 360-degree maps of the Sun and the inner heliosphere routinely, and(3) resolve the solar wind structures at multiple scales and multiple longitudes. With these capabilities, the solar Ring mission aims to address the origin of solar cycle, the origin of solar eruptions, the origin of solar wind structures and the origin of severe space weather events. The successful accomplishment of the mission will advance our understanding of the star and the space environment that hold our life and enhance our capability of expanding the next new territory of human.

关键词： space mission concept solar cycle solar eruptions solar wind space weather

Analysis of the correlation between horizontal wind and 11-year solar activity over Langfang, China

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Earth and Planetary Physics 2021年第3期5卷 270-279页

作者： Bing Cai QingChen Xu Xiong Hu Xuan Cheng JunFeng Yang Wen Li Key Laboratory of Science and Technology on Environmental Space Situation Awareness National Space Science CenterChinese Academy of SciencesBeijing 100190China College of Earth Sciences University of Chinese Academy of SciencesBeijing 100049China

In this study,long term observations of medium frequency(MF)radar at Langfang site(39.4°N,116.7°E)from 2009 to 2020 have been used to analyze the dependence of the 11-year solar cycle on horizontal winds in the local mesosphere and lower thermosphere(MLT).The results show that the zonal wind is positively correlated with solar activity during spring at 80–84 km,and during summer at 80–82 km;the meridional wind is positively correlated with solar activity during spring at 84–88 km and during summer at 84–90 km.In contrast,the results show no correlation between the horizontal wind and solar activity in autumn and winter.We attempt to explain the correlations in terms of the changes in stratospheric temperature and the net flux of gravity waves during solar activities.In addition,annual and semiannual oscillations of the zonal/meridional wind were found by using the least squares fitting method on daily horizontal winds,which show negative correlations with solar activity at heights of 80–90 km.

关键词： MF radar MLT horizontal wind solar cycle

Silver fir tree-ring fluctuations decrease from north to south latitude—total solar irradiance and NAO are indicated as the main influencing factors

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Forest Ecosystems 2023年第6期10卷 717-731页

作者： Vaclav Simůnek Anna Prokůpkova Zdenek Vacek Stanislav Vacek Jan Cukor Jirí Remes Vojtech Hajek Giuseppe D'Andrea Martin Salek Paola Nola Osvaldo Pericolo Sarka Holzbachova Francesco Ripullone Faculty of Forestry and Wood Sciences Czech University of Life Sciences PragueKamýcka 129CZ—16500Prague 6SuchdolCzech Republic Forestry and Game Management Research Institute v.v.iStrnady 13625202JílovisteCzech Republic Czech Academy of Sciences Institute of Vertebrate BiologyKvetna 860365BrnoCzech Republic Department of Earth and Environmental Sciences University of PaviaVia S.Epifanio 14I-27100PaviaItaly Forests of the Czech Republic SOEPremyslova 1106/19NovýHradec Kralove50008Hradec KraloveCzech Republic School of Agricultural Forestry and Environmental SciencesUniversity of BasilicataViale dell’Ateneo Lucano 10I-85100PotenzaItaly Faculty of Environmental Sciences Czech University of Life Sciences PragueKamýcka 129CZ—16500PragueSuchdolCzech Republic

Silver fir(Abies alba Mill.)is a flexible European tree species,mainly vegetating within the mountainous regions of Europe,but its growth responses across its latitudinal and longitudinal range have not yet been satisfactorily verified under changing environmental conditions.This study describes the tree-ring increment of silver fir in research plots across a latitudinal gradient from the northern range in Czechia(CZ),through Croatia(HR)to the southernmost range in Italy(IT).The research aims to analyze in detail the dynamics and cyclicity of the ringwidth index(RWI)and how it relates to climatic factors(temperature and precipitation),the North Atlantic Oscillation(NAO),and total solar irradiance(TSI),including the determination of latitude.The results show that the main drivers affecting fir growth are the seasonal NAO index and TSI.Monthly temperatures affect RWI early in the vegetation season,while lack of precipitation during the summer is a limiting factor for fir growth,especially in July.Seasonal temperatures and temperatures in June and July negatively impact,while seasonal precipitation totals in the same months positively influence the RWI in all research plots across meridian.The longest growth cycles in fir RWI were recorded in the northernmost studied plots in CZ.These cyclical fluctuations recede approaching the south.The cyclic increase in RWI is related to the TSI,which decreases its effect from north to south.The TSI's effects vary,positively impacting CZ but negatively influencing HR while remaining relatively neutral in IT.On the other hand,seasonal NAO tends to negatively affect silver fir growth in HR and CZ but has a mildly positive effect in IT.In conclusion,the TSI and the influence of the seasonal NAO index are prevalent in the fir RWI and are accompanied by a greater cyclicity of RWI in Central Europe(temperature optimum)than in the Italian Mediterranean region,where this tree species is limited by climatic conditions,especially lack of precipitation.

关键词： Abies alba Mill Tree-rings solar cycle North Atlantic oscillation Precipitation Temperature

Prospective results of CHANG'E-2 X-ray spectrometer

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Chinese Physics C 2009年第10期33卷 819-825页

作者：彭文溪王焕玉张承模崔兴柱曹学蕾张家宇梁晓华汪锦洲高旻杨家卫吴明烨 Institute of High Energy Physics CAS

The Chinese second lunar satellite CE-2, which carries an X-ray spectrometer （XRS）, will be launched at the end of 2010. In order to estimate the scientific results of XRS, we simulate the anticipated lunar X-ray spectra observed by XRS by using the expected mean solar X-ray flux in 2011. We also obtain the integration time and the spatial resolution required to achieve a certain significance level for the major lunar rock-forming elements in different solar activity conditions. It is expected that a spatial resolution of finer than 100 kilometers can be achieved for elements Mg, Al, Si, Ca, Ti, and Fe.

关键词： moon X-ray fluorescence solar cycle

Amplification of the solar Signal in the Summer Monsoon Rainband in China by Synergistic Actions of Different Dynamical Responses

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Journal of Meteorological Research 2017年第1期31卷 61-72页

作者： Liang ZHAO Jingsong WANG Haiwen LIU Ziniu XIAO State Key Laboratory of Numerical Modeling for Atmosphere Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 National Climate Center China Meteorological Administration Beijing 100081 China National Center for Space Weather Beijing 100081 Department of Aviation Meteorology Civil Aviation University of China Tianjin 300300

A rainband meridional shift index （RMSI） is defined and used to statistically prove that the East Asian summer monsoon rainband is usually significantly more northward in the early summer of solar maximum years than that of solar minimum years. By applying continuous wavelet transform, cross wavelet transform, and wavelet coherence, it is found that throughout most of the 20th century, the significant decadal oscillations of sunspot number （SSN） and the RMSI are phase-locked and since the 1960s, the SSN has led the RMSI slightly by approximately 1.4 yr. Wind and Eliassen-Palm （EP） flux analysis shows that the decadal meridional oscillation of the June rainband likely re- sults from both a stronger or earlier onset of the tropical monsoon and poleward shift of the subtropical westerly jet in high-solar months of May and June. The dynamical responses of the lower tropical monsoon and the upper subtropical westerly jet to the 11-yr solar cycle transmit bottom-up and top-down solar signals, respectively, and the synergistic actions between the monsoon and the jet likely amplify the solar signal at the northern boundary of the monsoon to some extent.

关键词： solar cycle rainband East Asian summer monsoon decadal variability EP flux precipitation

Signature of the 27-day variation in hemispheric sunspot activity and asymmetry during 2010-2015

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Research in Astronomy and Astrophysics 2021年第4期21卷 331-340页

作者： Prithvi Raj Singh Ahmad Islam Saad Farid Tarun Kumar Pant Abhay Kumar Singh Department of Physics Banaras Hindu UniversityVaranasi-221005India Physics and Chemistry Department Faculty of EducationAlexandria UniversityAlexandria-21526Egypt Space Physics Laboratory VSSCThiruvananthapuram-695022India

In the present work,we study the time evolution,significance of the N-S asymmetry excesses presented as a function of the solar cycle and prominent rotational periods(~27 d)separately for the northern and southern hemispheres.We have investigated short-term variations of the hemispheric solar activity(sunspot numbers and sunspot areas)during the time period 2010-2015,which covers the ascending and the maximum phase of solar cycle 24.We have implemented the Lomb-Scargle periodogram and continuous wavelet transform power spectrum techniques to study the time evolution and dominant rotational periods separately for the northern and southern hemispheres,and whole solar disk.Our results showed that the northern hemisphere exhibited longer solar synodic periods than the southern hemisphere,indicating that the northern hemisphere has a lower rotation rate.Moreover,the northern hemisphere was found to be dominant before transferring to the southern hemisphere during mid-2013.Also,the sunspot areas clearly demonstrated a two-peak structure of solar activity in the northern and southern hemispheres respectively during 2012 and 2014.The statistical significance of the southern hemisphere affirmed enhanced excess during the maximum phase of solar cycle 24.

关键词： Sunspots Sunspot Area Asymmetry solar cycle

Distributions and Structure of the solar Wind during solar cycles 23 and 24

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International Journal of Geosciences 2023年第9期14卷 813-826页

作者： Somaïla Koala Wendkouni Paulin Bere Yacouba Sawadogo Issamaïl Ki Jean Louis Zerbo Laboratoire de Matériaux d’Héliophysique et Environnement (La.M.H.E) Université Nazi BONI Bobo-Dioulasso Burkina Faso

To observe the level of interaction between the solar wind and the geomagnetic activity, we analyzed the distribution of the solar wind speeds according to the different classes of geomagnetic activity and the different phases of solar activity. We found that, the magnetic quiet activity reccord 80% of the solar wind speeds V s observed 88% of solar wind speeds V > 450 km/s. The shock activity observes 82% of the solar wind speeds V > 450 km/s. About 70% of the solar wind speeds V > 450 km/s, are observed in the corotating activity class. The cloud shock activity and fluctuating activity classes observed respectively 37% and 55% of the wind speeds V > 450 km/s. Furthermore, slow solar winds are mainly observed at the minimum phase of each solar cycle;but exceptionally the solar maximum phase of solar cycle 24, records a significant rate of slow solar wind. Shock winds are mainly observed around the solar maximum and recurrent winds are mainly observed at the descending phase of the solar cycle. Corotating stable winds and moderate shock winds dominate respectively at the descending phase and at the maximum phase.

关键词： solar Wind solar Activity Geomagnetic Activity solar cycle

Seasonal Variations of solar Wind Parameters during solar cycles 23 and 24

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Open Journal of Applied Sciences 2022年第9期12卷 1527-1546页

作者： Somaïla Koala Yacouba Sawadogo Jean Louis Zerbo Laboratoire de Matériaux d’Héliophysique et Environnement (La.M.H.E) ED/ST Université Nazi BONI Bobo-Dioulasso Burkina Faso Unité de Formation et de Recherche en Sciences Exactes et Appliquées (UFR/SEA) Université Nazi BONI Bobo-Dioulasso Burkina Faso

In this paper, we analyzed diurnal and annual seasonal variations of solar wind parameters such as interplanetary magnetic field (IMF), proton density (N), solar wind speed (V) and solar wind dynamic pressure (Pdym), during the solar cycles 23 and 24. Our study shows that strong geomagnetic disturbances are observed at the equinoxes during both solar cycles. The highest proton densities are observed at solstices during both solar cycles. The greatest solar wind speeds are observed at the equinoxes of solar cycle 23 and at the solstices of solar cycle 24. The highest solar wind dynamic pressures are observed at the solstices of both solar cycles. We also observed an asymmetrical evolution of the seasonal diurnal values of the solar wind parameters during the two cycles, except for the proton density. Our investigations also highlight the fact that the seasonal diurnal values of the solar wind parameters are significant at solar cycle 23 compared to solar cycle 24 characterized by a global weak in solar plasma conditions since the deep minimum that followed the solar cycle 23 leading to an absence of a persistent polar coronal hole. The drop observed in polar field and solar winds parameters during solar cycle 24 is reproduced on seasons (solstices and equinoxes). The solar cycle 23 and 24 appear to be two magnetically opposite solar cycles regardless the time scales.

关键词： Diurnal Seasonal solar Winds Parameters Variation solar cycle