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Periodicities in Solar Activity, Solar Radiation and Their Links with Terrestrial Environment
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作者 Valentina V. Zharkova Irina Vasilieva +1 位作者 Simon J. Shepherd Elena Popova 《Natural Science》 CAS 2023年第3期111-147,共37页
Solar magnetic activity is expressed via variations of sunspots and active regions varying on different timescales. The most accepted is an 11-year period supposedly induced by the electromagnetic solar dynamo mechani... Solar magnetic activity is expressed via variations of sunspots and active regions varying on different timescales. The most accepted is an 11-year period supposedly induced by the electromagnetic solar dynamo mechanism. There are also some shorter or longer timescales detected: the biennial cycle (2 - 2.7 years), Gleisberg cycle (80 - 100 years), and Hallstatt’s cycle (2100 - 2300 years). Recently, using Principal Component Analysis (PCA) of the observed solar background magnetic field (SBMF), another period of 330 - 380 years, or Grand Solar Cycle (GSC), was derived from the summary curve of two eigenvectors of SBMF. In this paper, a spectral analysis of the averaged sunspot numbers, solar irradiance, and the summary curve of eigenvectors of SBMF was carried out using Morlet wavelet and Fourier transforms. We detect a 10.7-year cycle from the sunspots and modulus summary curve of eigenvectors as well a 22-year-cycle and the grand solar cycle of 342 - 350-years from the summary curve of eigenvectors. The Gleissberg centennial cycle is only detected on the full set of averaged sunspot numbers for 400 years or by adding a quadruple component to the summary curve of eigenvectors. Another period of 2200 - 2300 years is detected in the Holocene data of solar irradiance measured from the abundance of 14C isotope. This period was also confirmed with the period of about 2000 - 2100 years derived from a baseline of the solar background magnetic field, supposedly, caused by the solar inertial motion (SIM) induced by the gravitation of large planets. The implication of these findings for different deposition of solar radiation into the northern and southern hemispheres of the Earth caused by the combined effects of the solar activity and solar inertial motion on the terrestrial atmosphere is also discussed. 展开更多
关键词 sun: Magnetic Field sun: solar activity sun: sunspots sun: solar Dynamo
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Terrestrial Temperature, Sea Levels and Ice Area Links with Solar Activity and Solar Orbital Motion
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作者 Valentina V. Zharkova Irina Vasilieva 《Natural Science》 2023年第9期233-255,共23页
This paper explores the links between terrestrial temperature, sea levels and ice areas in both hemispheres with solar activity indices expressed through averaged sunspot numbers together with the summary curve of eig... This paper explores the links between terrestrial temperature, sea levels and ice areas in both hemispheres with solar activity indices expressed through averaged sunspot numbers together with the summary curve of eigenvectors of the solar background magnetic field (SBMF) and with changes of Sun-Earth distances caused by solar inertial motion resulting from the gravitation of large planets in the solar system. Using the wavelet analysis of the GLB and HadCRUTS datasets two periods: 21.4 and 36 years in GLB, set and the period of about 19.6 years in the HadCRUTS are discovered. The 21.4-year period is associated with variations in solar activity defined by the summary curve of the largest eigenvectors of the SBMF. A dominant 21.4-year period is also reported in the variations of the sea level, which is linked with the period of 21.4 years detected in the GLB temperature and the summary curve of the SBMF variations. The wavelet analysis of ice and snow areas shows that in the Southern hemisphere, it does not show any links to solar activity periods while in the Northern hemisphere, the ice area reveals a period of 10.7 years equal to a usual solar activity cycle. The TSI in March-August of every year is found to grow with every year following closely the temperature curve, because the Sun moves closer to the Earth orbit owing to gravitation of large planets (solar inertial motion, SIM), while the variations of solar radiation during a whole year have more steady distribution without a sharp TSI increase during the last two centuries. The additional TSI contribution caused by SIM is likely to secure the additional energy input and exchange between the ocean and atmosphere. 展开更多
关键词 sun: Magnetic Field sun: solar activity sun: Inertial Motion Earth: Temperature Earth: Sea Level Earth: Ice Area
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Periodic variation and phase analysis of grouped solar flare with sunspot activity
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作者 Hui Deng Ying Mei Feng Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第2期75-84,共10页
Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycles.Here we report the statistical ana... Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycles.Here we report the statistical analysis of grouped solar flare(GSF) and sunspot number(SN) during the time interval from January 1965 to March 2009.We find that,(1) the significant periodicities of both GSF and SN are related to the differential rotation periodicity,the quasi-biennial oscillation(QBO),and the eleven-year Schwabe cycle(ESC),but the specific values are not absolutely identical;(2) the ESC signal of GSF lags behind that of SN with an average of 7.8 months during the considered time interval,which implies that the systematic phase delays between GSF and SN originate from the inter-solar-cycle signal.Our results may provide evidence about the storage of magnetic energy in the corona. 展开更多
关键词 sun:sunspots sun:flares sun:activity sun:magnetic fields
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Latitudinal migration of sunspots based on the ESAI database
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作者 Juan Zhang Fu-Yu Li Wen Feng 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第1期83-94,共12页
The latitudinal migration of sunspots toward the equator,which implies there is propagation of the toroidal magnetic flux wave at the base of the solar convection zone,is one of the crucial observational bases for the... The latitudinal migration of sunspots toward the equator,which implies there is propagation of the toroidal magnetic flux wave at the base of the solar convection zone,is one of the crucial observational bases for the solar dynamo to generate a magnetic field by shearing of the pre-existing poloidal magnetic field through differential rotation.The Extended time series of Solar Activity Indices(ESAI)elongated the Greenwich observation record of sunspots by several decades in the past.In this study,ESAI's yearly mean latitude of sunspots in the northern and southern hemispheres during the years 1854 to 1985 is utilized to statistically test whether hemispherical latitudinal migration of sunspots in a solar cycle is linear or nonlinear.It is found that a quadratic function is statistically significantly better at describing hemispherical latitudinal migration of sunspots in a solar cycle than a linear function.In addition,the latitude migration velocity of sunspots in a solar cycle decreases as the cycle progresses,providing a particular constraint for solar dynamo models.Indeed,the butterfly wing pattern with a faster latitudinal migration rate should present stronger solar activity with a shorter cycle period,and it is located at higher latitudinal position,giving evidence to support the Babcock-Leighton dynamo mechanism. 展开更多
关键词 sunactivity sun:general sunsunspots methods:data analysis
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Evolution of the Level of Sunspot Activity in Solar Cycles I. Evolution in the Descending Phase 被引量:2
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作者 Jia-Long Wang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2006年第3期354-362,共9页
Taking the 13-point smoothed monthly sunspot number,Ri, and the deviation of the 13 associated monthly sunspot numbers from the smoothed one, Di, as a number-pair describing the global level of sunspot activity, the e... Taking the 13-point smoothed monthly sunspot number,Ri, and the deviation of the 13 associated monthly sunspot numbers from the smoothed one, Di, as a number-pair describing the global level of sunspot activity, the evolution of the level is statistically studied for the period from the month which is just 48 months before the minimum to the minimum in the descending phase, using the observed data of Solar Cycles 10 to 22. Our results show (1) for 46 months (94%) of the studied 49 months it is found that for a given month, the distribution of the 13 pairs which come from the 13 solar cycles on a log Ri - Di plane may be fitted by a straight line with a correlation coefficient larger than the critical one at confidence level a = 5%, and for 36 months (73%) the fitting is even better, for a = 1%; (2) time variations of these two parameters and their correlations in the studied period can be described respectively by functions of time, whose main trends may be expressed by a linear or simple curvilinear function; (3) the evolutionary path of the level of sunspot activity may be represented by a logarithmic function as log/~ = 0.704 lnDi - 0.291. 展开更多
关键词 sun - sunspots - active level evolution
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The relationships of solar flares with both sunspot and geomagnetic activity 被引量:1
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作者 Zhan-Le Du Hua-Ning Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2012年第4期400-410,共11页
The relationships between solar flare parameters (total importance, time duration, flare index, and flux) and sunspot activity (R z ) as well as those between geomagnetic activity (aa index) and the flare parame... The relationships between solar flare parameters (total importance, time duration, flare index, and flux) and sunspot activity (R z ) as well as those between geomagnetic activity (aa index) and the flare parameters can be well described by an integral response model with the response time scales of about 8 and 13 months, respectively. Compared with linear relationships, the correlation coefficients of the flare parameters with R z , of aa with the flare parameters, and of aa with R z based on this model have increased about 6%, 17%, and 47% on average, respectively. The time delays between the flare parameters with respect to R z , aa to the flare parameters, and aa to R z at their peaks in a solar cycle can be predicted in part by this model (82%, 47%, and 78%, respectively). These results may be further improved when using a cosine filter with a wider window. It implies that solar flares are related to the accumulation of solar magnetic energy in the past through a time decay factor. The above results may help us to understand the mechanism of solar flares and to improve the prediction of the solar flares. 展开更多
关键词 sun activity -- sun sunspots -- sun flares -- geomagnetic activity
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The hemispheric asymmetry of solar activity during the last century and the solar dynamo 被引量:2
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作者 Ashish Goel Arnab Rai Choudhuri 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第1期115-126,共12页
We believe the Babcock-Leighton process of poloidal field generation to be the main source of irregularity in the solar cycle. The random nature of this process may make the poloidal field in one hemisphere stronger t... We believe the Babcock-Leighton process of poloidal field generation to be the main source of irregularity in the solar cycle. The random nature of this process may make the poloidal field in one hemisphere stronger than that in the other hemisphere at the end of a cycle. We expect this to induce an asymmetry in the next sunspot cycle. We look for evidence of this in the observational data and then model it theoretically with our dynamo code. Since actual polar field measurements exist only from the 1970s, we use the polar faculae number data recorded by Sheeley (1991, 2008) as a proxy of the polar field and estimate the hemispheric asymmetry of the polar field in different solar minima during the major part of the twentieth century. This asymmetry is found to have a reasonable correlation with the asymmetry of the next cycle. We then run our dynamo code by feeding information about this asymmetry at the successive minima and compare the results with observational data. We find that the theoretically computed asymmetries of different cycles compare favorably with the observational data, with the correlation coefficient being 0.73. Due to the coupling between the two hemispheres, any hemispheric asymmetry tends to get attenuated with time. The hemispheric asymmetry of a cycle either from observational data or from theoretical calculations statistically tends to be less than the asymmetry in the polar field (as inferred from the faculae data) in the preceding minimum. This reduction factor turns out to be 0.43 and 0.51 respectively in observational data and theoretical simulations. 展开更多
关键词 sun activity -- sun magnetic fields -- sunspots
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Investigation of a Possible Link between Solar Activity and Climate Change in Saudi Arabia: Rainfall Patterns
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作者 Abdullrahman H. Maghrabi Hadeel A. Alamoudi Aied S. Alruhaili 《Atmospheric and Climate Sciences》 2023年第4期478-490,共13页
In this study, annual, quarterly, and monthly mean precipitation data in Saudi Arabia were correlated with sunspot number (SSN) and galactic cosmic ray (CR) flux over 35 years (1985-2019). The results show that the st... In this study, annual, quarterly, and monthly mean precipitation data in Saudi Arabia were correlated with sunspot number (SSN) and galactic cosmic ray (CR) flux over 35 years (1985-2019). The results show that the strength, magnitude, proportion and statistical significance of the relationship between precipitation and the two variables varied by season and month. We find that mean annual precipitation in Saudi Arabia, from May to November, and summer and autumn are correlated with cosmic rays and inversely correlated with SSN. Correlations of varying intensities and scales were found during the remaining months and during winter and spring. The relationships between the rainfall and SSN and CR for each solar cycle were investigated and showed that for all three cycles, the annual rainfall over Saudi Arabia has a positive correlation with CR. Different results were obtained when the seasonal rainfall data correlated with the SSNs and CRs during each cycle. The results obtained, in terms of their strength and magnitude, are affected by terrestrial and extra-terrestrial factors. These factors have been briefly presented and discussed. These findings represent a step towards understanding the possible role of solar activity in climate change for future meteorological phenomenon forecasting, even if the physical mechanism is still poorly quantified. 展开更多
关键词 PRECIPITATION Cosmic Rays solar activity Climate Change sunSPOT Saudi Arabia
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Predicting the 25th solar cycle using deep learning methods based on sunspot area data 被引量:2
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作者 Qiang Li Miao Wan +2 位作者 Shu-Guang Zeng Sheng Zheng Lin-Hua Deng 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第7期290-298,共9页
It is a significant task to predict the solar activity for space weather and solar physics. All kinds of approaches have been used to forecast solar activities, and they have been applied to many areas such as the sol... It is a significant task to predict the solar activity for space weather and solar physics. All kinds of approaches have been used to forecast solar activities, and they have been applied to many areas such as the solar dynamo of simulation and space mission planning. In this paper, we employ the long-shortterm memory(LSTM) and neural network autoregression(NNAR) deep learning methods to predict the upcoming 25 th solar cycle using the sunspot area(SSA) data during the period of May 1874 to December2020. Our results show that the 25 th solar cycle will be 55% stronger than Solar Cycle 24 with a maximum sunspot area of 3115±401 and the cycle reaching its peak in October 2022 by using the LSTM method. It also shows that deep learning algorithms perform better than the other commonly used methods and have high application value. 展开更多
关键词 sun:activity sun:solar cycle prediction sun:sunspot area Method:deep neural network
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A study of short-period variation in solar activity
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作者 Ji-Long Chen Juan Zhao 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第8期1011-1018,共8页
We introduce two methods to detect short-period variation in solar activity. These are called amplitude of low frequency fluctuation (ALFF) and fractional am- plitude of low frequency fluctuation (FALFF). We find ... We introduce two methods to detect short-period variation in solar activity. These are called amplitude of low frequency fluctuation (ALFF) and fractional am- plitude of low frequency fluctuation (FALFF). We find a positive correlation between short-period variation and 11-year variation of solar activity using these two methods. Through ALFF, we find that solar activity over a short period becomes intensive when the 11-year solar activity is intensive. The ALFF value of the short period activity varies with the peak in sunspot number as a quadratic function. Through FALFF we find that the ratio of short-period spectral intensity to intensity over the whole period of solar activity will increase when the 11-year period of solar activity is intensive. The short-period FALFF value varies with the peak in sunspot number according to a cubic function. Using ALFF, we obtain a yearly series of solar activity that varies over a short period of 1-5 yr from 1860 to 2003, which shows an obvious periodicity of about 22 yr, 33 yr, 11 yr and a century. These short period variations show good correlations with long term variations in solar activity. 展开更多
关键词 sun activity -- sun sunspots -- methods data analysis
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Wavelet Analysis of the Schwabe Cycle Properties in Solar Activity 被引量:7
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作者 Gui-Ming LeNational Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 Center for Space Science and Applied Research Center, Chinese Academy of Sciences, Beijing 100080 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2004年第6期578-582,共5页
Properties of the Schwabe cycles in solar activity are investigated by using wavelet transform. We study the main range of the Schwabe cycles of the solar activity recorded by relative sunspot numbers, and find that t... Properties of the Schwabe cycles in solar activity are investigated by using wavelet transform. We study the main range of the Schwabe cycles of the solar activity recorded by relative sunspot numbers, and find that the main range of the Schwabe cycles is the periodic span from 8-year to 14-year. We make the comparison of 11-year’s phase between relative sunspot numbers and sunspot group numbers. The results show that there is some difference between two phases for the interval from 1710 to 1810, while the two phases are almost the same for the interval from 1810 to 1990. 展开更多
关键词 sun sunSPOT sun activity method data analysis
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The Effect of Solar Activity on the Annual Precipitation in the Beijing Area 被引量:6
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作者 JuanZhao Yan-BenHan Zhi-AnLi 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2004年第2期189-197,共9页
Using continuous wavelet transform, we examine the relationship between solar activity and the annual precipitation in the Beijing area. The results indicate that the annual precipitation is closely related to the var... Using continuous wavelet transform, we examine the relationship between solar activity and the annual precipitation in the Beijing area. The results indicate that the annual precipitation is closely related to the variation of sunspot numbers, and that solar activity probably plays an important role in influencing the precipitation on land. 展开更多
关键词 sun: activity sunspots solar-terrestrial relation
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Phase analysis of sunspot group numbers on both solar hemispheres 被引量:2
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作者 Lin-Hua Deng Zhong-Quan Qu +1 位作者 Xiao-Li Yan Kai-Rang Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2013年第1期104-114,共11页
Cross-correlation analysis and wavelet transform methods are proposed to investigate the phase relationship between the monthly sunspot group numbers in the solar northern and southern hemispheres. It is found that (... Cross-correlation analysis and wavelet transform methods are proposed to investigate the phase relationship between the monthly sunspot group numbers in the solar northern and southern hemispheres. It is found that (1) the monthly sunspot group numbers in the northern hemisphere begin two months earlier than those in the southern one, which should lead to phase asynchrony between them but with a slight effect; (2) the Schwabe cycle length for the monthly sunspot group numbers in the two hemispheres obviously differs from each other, and the mean Schwabe cycle length of the monthly sunspot group numbers in the northern hemisphere is slightly larger than that in the southern one; (3) the monthly sunspot group numbers in the northern hemisphere precede those in the southern hemisphere during the years of about 1874- 1927, after which, the southern hemisphere leads the northern hemisphere in the years 1928-1964, and then the northern hemisphere leads in time till the present. 展开更多
关键词 methods data analysis -- sun activity -- sun sunspots
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Low-dimensional chaos and fractal properties of long-term sunspot activity
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作者 Shuang Zhou Yong Feng +2 位作者 Wen-Yuan Wu Yi Li Jiang Liu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第1期104-112,共9页
Two primary solar-activity indicators- sunspot numbers (SNs) and sunspot areas (SAs) in the time interval from November 1874 to December 2012 - are used to determine the chaotic and fractal properties of solar act... Two primary solar-activity indicators- sunspot numbers (SNs) and sunspot areas (SAs) in the time interval from November 1874 to December 2012 - are used to determine the chaotic and fractal properties of solar activity. The results show that (1) the long-term solar activity is governed by a low-dimensional chaotic strange attractor, and its fractal motion shows a long-term persistence on large scales; (2) both the fractal dimension and maximal Lyapunov exponent of SAs are larger than those of SNs, implying that the dynamical system of SAs is more chaotic and complex than SNs; (3) the predictions of solar activity should only be done for short- to mid-term behaviors due to its intrinsic complexity; moreover, the predictability time of SAs is obviously smaller than that of SNs and previous results. 展开更多
关键词 methods: data analysis -- sun activity -- sun sunspots
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ENSO Index Variations and Links with Solar and Volcanic Activity
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作者 Valentina V. Zharkova Irina Vasilieva 《Natural Science》 2024年第4期25-44,共20页
In this paper, we investigated the Oceanic Niño Index (ONI), for simplicity called in this paper an El Nino Southern Oscillation (ENSO) index in 1950-2023 by applying the wavelet spectral transform and the IBM SP... In this paper, we investigated the Oceanic Niño Index (ONI), for simplicity called in this paper an El Nino Southern Oscillation (ENSO) index in 1950-2023 by applying the wavelet spectral transform and the IBM SPSS correlations analysis. ONI follows the three months’ current measurements of the average temperature of the sea surface in the East-Central tropical part of the Pacific Ocean nearby the international line of the date change over the average sea surface temperature over the past 30 years. The ENSO index is found to have a strong (>87%) correlation with the Global Land-Ocean Temperature (GLOT). The scatter plots of the ENSO-GLOT correlation with the linear and cubic fits have shown that the ENSO index is better fit by the cubic polynomial increasing proportionally to a cubic power of the GLOT variations. The wavelet analysis allowed us to detect the two key periods in the ENSO (ONI) index: 4 - 5 years and 12 years. The smaller period of 4.5 years can be linked to the motion of tectonic plates while the larger period of 12 years is shown to have a noticeable correlation of 25% with frequencies of the underwater (submarine) volcanic eruptions in the areas with ENSO occurrences. Not withholding any local terrestrial factors considered to contribute to the ENSO occurrences, we investigated the possibility of the volcanic eruptions causing ENSO to be also induced by the tidal forces of Jupiter and Sun showing the correlation of the underwater volcanic eruption frequency with the Jupiter-Earth distances to be 12% and with the Sun-Earth distances, induced by the solar inertial motion, in January, when the Earth is turned to the Sun with the southern hemisphere where the ENSO occurs, to become 15%. Hence, the underwater volcanic eruptions induced by tidal forces of Jupiter and Sun can be the essential additional factors imposing this 12 year period of the ENSO (ONI) index variations. 展开更多
关键词 sun: Magnetic Field sun: solar activity sun: Inertial Motion Earth: Temperature Earth: Sea Level Earth: Ice Area
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A Statistical Study of Rapid Sunspot Structure Change Associated with Flares 被引量:1
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作者 Wei-Zhong Chen Chang Liu Hui Song Na Deng Chang-Yi Tan Hai-Min Wang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第5期733-742,共10页
We reported recently some rapid changes of sunspot structure in white-light (WL) associated with major flares. We extend the study to smaller events and present here results of a statistical study of this phenomenon... We reported recently some rapid changes of sunspot structure in white-light (WL) associated with major flares. We extend the study to smaller events and present here results of a statistical study of this phenomenon. In total, we investigate 403 events from 1998 May 9 to 2004 July 17, including 40 X-class, 174 M-class, and 189 C-class flares. By monitoring the structure of the flaring active regions using the WL observations from the Transition Region and Coronal Explorer (TRACE), we find that segments in the outer sunspot structure decayed rapidly right after many flares; and that, on the other hand, the central part of sunspots near the flare-associated magnetic neutral line became darkened. These rapid and permanent changes are evidenced in the time profiles of WL mean intensity and are not likely resulted from the flare emissions. Our study further shows that the outer sunspot structure decay as well as the central structure darkening are more likely to be detected in larger solar flares. For X-class flares, over 40% events show distinct sunspot structure change. For M- and C-class flares, this percentage drops to 17% and 10%, respectively. The results of this statistical study support our previously proposed reconnection picture, i.e., the flare-related magnetic fields evolve from a highly inclined to a more vertical configuration. 展开更多
关键词 sun activity -- sun flares -- sun magnetic fields -- sunspots
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Can Asymmetry of Solar Activity be Extended into Extended Cycle? 被引量:1
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作者 Ke-JunLi Jing-XiuWang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2002年第1期66-70,共5页
With the use of the Royal Greenwich Observatory data set of sunspot groups, an attempt is made to examine the north-south asymmetry of solar activity in the 'extended' solar cycles. It is inferred that the asy... With the use of the Royal Greenwich Observatory data set of sunspot groups, an attempt is made to examine the north-south asymmetry of solar activity in the 'extended' solar cycles. It is inferred that the asymmetry established for individual solar cycles does not extend to the 'extended' cycles. 展开更多
关键词 sun: sunspot - sun: active cycle - sun: activity
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Low Dimensional Chaos from the Group Sunspot Numbers 被引量:2
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作者 Qi-Xiu Li Ke-Jun Li 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第3期435-440,共6页
We examine the nonlinear dynamical properties of the monthly smoothed group sunspot number Rg and find that the solar activity underlying the time series of Rg is globally governed by a low-dimensional chaotic attract... We examine the nonlinear dynamical properties of the monthly smoothed group sunspot number Rg and find that the solar activity underlying the time series of Rg is globally governed by a low-dimensional chaotic attractor. This finding is consistent with the nonlinear study results of the monthly Wolf sunspot numbers. We estimate the maximal Lyaponuv exponent (MLE) for the Rg series to be positive and to equal approximately 0.0187 ± 0.0023 (month^- 1). Thus, the Lyaponuv time or predictability time of the chaotic motion is obtained to be about 4.46 ± 0.5 years, which is slightly different with the predictability time obtained from Rz. However, they both indicate that solar activity forecast should be done only for a short to medium term due to the intrinsic complexity of the time behavior concerned. 展开更多
关键词 sun activity - sun sunspot - chaos - sun Wolf sunspot numbers
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How much has the Sun influenced Northern Hemisphere temperature trends?An ongoing debate 被引量:2
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作者 Ronan Connolly Willie Soon +20 位作者 Michael Connolly Sallie Baliunas Johan Berglund C.John Butler Rodolfo Gustavo Cionco Ana G.Elias Valery M.Fedorov Hermann Harde Gregory W.Henry Douglas V.Hoyt Ole Humlum David R.Legates Sebastian Liming Nicola Scafetta Jan-Erik Solheim Laszlo Szarka Harry van Loon Victor M.Velasco Herrera Richard C.Willson Hong Yan Weijia Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第6期131-198,共68页
In order to evaluate how much Total Solar Irradiance(TSI)has influenced Northern Hemisphere surface air temperature trends,it is important to have reliable estimates of both quantities.Sixteen different estimates of t... In order to evaluate how much Total Solar Irradiance(TSI)has influenced Northern Hemisphere surface air temperature trends,it is important to have reliable estimates of both quantities.Sixteen different estimates of the changes in TSI since at least the 19th century were compiled from the literature.Half of these estimates are"low variability"and half are"high variability".Meanwhile,five largely-independent methods for estimating Northern Hemisphere temperature trends were evaluated using:1)only rural weather stations;2)all available stations whether urban or rural(the standard approach);3)only sea surface temperatures;4)tree-ring widths as temperature proxies;5)glacier length records as temperature proxies.The standard estimates which use urban as well as rural stations were somewhat anomalous as they implied a much greater warming in recent decades than the other estimates,suggesting that urbanization bias might still be a problem in current global temperature datasets-despite the conclusions of some earlier studies.Nonetheless,all five estimates confirm that it is currently warmer than the late 19th century,i.e.,there has been some"global warming"since the 19th century.For each of the five estimates of Northern Hemisphere temperatures,the contribution from direct solar forcing for all sixteen estimates of TSI was evaluated using simple linear least-squares fitting.The role of human activity on recent warming was then calculated by fitting the residuals to the UN IPCC’s recommended"anthropogenic forcings"time series.For all five Northern Hemisphere temperature series,different TSI estimates suggest everything from no role for the Sun in recent decades(implying that recent global warming is mostly human-caused)to most of the recent global warming being due to changes in solar activity(that is,that recent global warming is mostly natural).It appears that previous studies(including the most recent IPCC reports)which had prematurely concluded the former,had done so because they failed to adequately consider all the relevant estimates of TSI and/or to satisfactorily address the uncertainties still associated with Northern Hemisphere temperature trend estimates.Therefore,several recommendations on how the scientific community can more satisfactorily resolve these issues are provided. 展开更多
关键词 sun:activity (sun:)solar terrestrial relations (sun:)sunspots sun:faculae plages
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Application of the Cross Wavelet Transform to Solar Activity and Major Earthquakes Occurred in Chile
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作者 Patricia Alejandra Larocca 《International Journal of Geosciences》 2016年第11期1310-1317,共9页
Historical earthquakes registered in Chile (from 1900 up to 2015) with epicenters located between 17?30'S and 56?0'S latitude and yearly mean total sunspot number have been considered in order to evaluate a si... Historical earthquakes registered in Chile (from 1900 up to 2015) with epicenters located between 17?30'S and 56?0'S latitude and yearly mean total sunspot number have been considered in order to evaluate a significant linkage between them. The occurrence of strong earthquakes along Chile and the sunspots activity are analyzed to inspect possible influence of solar cycles on earthquakes. The cross wavelet transform and wavelet coherence analysis were applied for sequences of sunspots and earthquakes activity. An 8 - 12 years modulation of earthquakes activity has been identified. 展开更多
关键词 Cross Wavelet Transform Earthquakes activity solar activity sunspots Number PERIODICITIES
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