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1.
In the present study, the north–south asymmetry of filaments in solar cycles 16–21 is investigated with the use of the solar filaments observed at the Observatoire de Paris, Section de Meudon from March 1919 to December 1989. Filament activity is found regularly dominated in each of cycles 16–21 in the same hemisphere as that inferred by sunspot activity, and it is found to run in a different asymmetrical behavior at different latitudinal bands, suggesting that the north–south asymmetry of filament activity should be a function of latitudes. The regularity on the north–south asymmetry of sunspot activity given by Li et al. (2002b) is demonstrated by filament activity. The periods in the north–south asymmetry of solar filament activity are 9.13, and 12.8 years without the solar cycle found. 相似文献
2.
太阳活动周期的小波分析 总被引：5，自引：0，他引：5
运用小波技术对太阳射电流量2800 MHz,太阳黑子数和太阳黑子面积数周期进行分析．其结果表明: (1)这3个系列的数据显示最显著的周期是10．69年,其他周期并不明显．(2)小波功率谱给出了全部时间-周期范围的功率谱变化,它显示了在某个周期处于某个时段的局部功率的变化,小波功率谱分析表明,小于1年的周期仅仅在太阳活动最大期附近比较明显．(3)太阳射电2800 MHz,太阳黑子数和太阳黑子面积数的几个周期(10．69年,5．11年, 155．5天)的小波功率谱比较相似,出现峰值的时间相同;曲线的起伏相似,周期越小,曲线起伏的频率越大． 相似文献
3.
Wavelet Analysis of solar,solar wind and geomagnetic parameters 总被引：3，自引：0，他引：3
The sunspot number, solar wind plasma, interplanetary magnetic field, and geomagnetic activity index A
p have been analyzed using a wavelet technique to look for the presence of periods and the temporal evolution of these periods. The global wavelet spectra of these parameters, which provide information about the temporal average strength of quasi periods, exhibit the presence of a variety of prominent quasi periods around 16 years, 10.6 years, 9.6 years, 5.5 years, 1.3 years, 180 days, 154 days, 27 days, and 14 days. The wavelet spectra of sunspot number during 1873–2000, geomagnetic activity index A
p during 1932–2000, and solar wind velocity and interplanetary magnetic field during 1964–2000 indicate that their spectral power evolves with time. In general, the power of the oscillations with a period of less than one year evolves rapidly with the phase of the solar cycle with their peak values changing from one cycle to the next. The temporal evolution of wavelet power in R
z, v
sw, n, B
y, B
z, |B|, and A
p for each of the prominent quasi periods is studied in detail. 相似文献
4.
22周上升相日面各经度带的活动规律 总被引：1，自引：0，他引：1
本文回顾了１９８３年以来一些对太阳活动的谱分析结果。大致可分为两种规律：在太阳活动１１年周期的上升相一般呈现８０天左右的周期。下降相呈现１５０天左右的周期。这些规律均是由太阳全日面总体活动指数得到的谱分析结果。文中将第２２周上升段（１９８７．１．１—１９８８．７．３１）的太阳黑子群和Ｘ射线耀斑按经度带作了极大熵谱估计。结果表明，各经度带的活动规律不同，同一经度带内，太阳黑子群和Ｘ射线耀斑的出现规律也不尽相同。这种将事件按经度带分布得到的活动规律对事件本身的中期预报将会有实际应用价值。 相似文献
5.
Influence of the solar activity on the Indian Monsoon rainfall 总被引：1，自引：0，他引：1
We use 130 years data for studying correlative effects due to solar cycle and activity phenomena on the occurrence of the Indian Monsoon rainfall. We compute the correlation coefficients and significance of correlation coefficients for the seasonal and the annual data. We find that: (i) for the whole years 1871–2000, the spring and southwest monsoon rainfall variabilities have significant positive correlations with the sunspot activity during the corresponding period, (ii) the FFT and the wavelet analyses of the southwest monsoon rainfall variability show the periods 2.7, 16 and 22 year, respectively (similar to the periods found in sunspot occurrence data) and, (iii) there is a long-term trend indicating a gradual decrease of occurrence of rainfall variability by nearly 2.3 ± 1.3 mm/year and increase of sunspot activity by nearly 3.9 ± 1.5 sunspots/year compared to the activity of previous solar cycle.
We speculate in this study a possible physical connection between the occurrence of the rainfall variability and the sunspot activity, and the flux of galactic cosmic rays. Owing to long-term positive and significant correlation of the spring and southwest monsoon rainfall variabilities with the sunspot activity, it is suggested that solar activity may be included as one of the crucial parameter in modeling and predicting the Indian monsoon rainfall. 相似文献
6.
The wavelet analysis of the period of solar activity 总被引：1，自引：0，他引：1
Zhan La-sheng He Juan-mei Ye Yi-lin Zhao Hai-juan 《Chinese Astronomy and Astrophysics》2006,30(4):393-401
Using the wavelet technique, we analyzed the time series of solar radio fluxes at 2800 MHz as well as sunspot numbers and areas. The results are as follows: (1) These three data sets demonstrate that the most prominent period is 10.69 years and that all other periods are not obvious. (2) The wavelet power spectrum displays the changes of the power spectrum over the entire time-period range and shows the variations in the local power of a given period in a given time interval. Our analysis shows that periods shorter than one year are distinct only around solar activity maximum. (3) The time curves of the wavelet power at three periods (10.69 years, 5.11 years and 155.5 days) for the three times series are rather alike, with the same times of peaks and similar undulations. The shorter the period, the more frequent the fluctuations. 相似文献
7.
The periodicity of high-latitude solar activity has been studied with the use of the Carte Synoptique solar filaments archive.
The Morlet wavelet is utilized to analyze the periodicity of the number of solar filaments at latitudes over 50° during Carrington
solar rotations 876 – 1823. For solar filaments at latitudes over 50°, the most eminent periods are about 10.23 and 10.90
years, which correspond to the Schwabe period of high-latitude solar activity, and the these periods make-up a highly significant
proportion of the time span considered. The periods of 1.3 and 1.7 years and the quasi-biennial 2 – 3-year oscillation often
mentioned in the literature are not found to be a feature of every solar cycle but seem to appear only from time to time. 相似文献
8.
Large-scale distribution of the sunspot activity of the Sun has been analyzed by using a technique worked out previously (Erofeev, 1997) to study long-lived, non-axisymmetric magnetic structures with different periods of rotation. Results of the analysis have been compared with those obtained by analyzing both the solar large-scale magnetic field and large-scale magnetic field simulated by means of the well-known flux transport equation using the sunspot groups as a sole source of new magnetic flux in the photosphere. A 21-year period (1964–1985) has been examined.The rotation spectra calculated for the total time interval of two 11-year cycles indicate that sunspot activity consists of a series of discrete components (modes) with different periods of rotation. The largest-scale component of the sunspot activity reveals modes with 27-day and 28-day periods of rotation situated, correspondingly, in the northern and southern hemispheres of the Sun, and two modes with rotation periods of about 29.7 days situated in both hemispheres. Such a modal structure of the sunspot activity agrees well with that of the large-scale solar magnetic field. Moreover, the magnetic field distribution simulated with the flux transport equation also reveals the same modal structure. However, such an agreement between the large-scale solar magnetic field and both the sunspot activity and simulated magnetic field is unstable in time; so, it is absent in the northern hemisphere of the Sun during solar cycle No. 20. Thus the sources of magnetic flux responsible for formation of the large-scale, rigidly rotating magnetic patterns appear to be closely connected, but are not identical with the discrete modes of the sunspot activity. 相似文献
9.
《New Astronomy》2017
Total solar irradiance (TSI) is the primary quantity of energy that is provided to the Earth. The properties of the TSI variability are critical for understanding the cause of the irradiation variability and its expected influence on climate variations. A deterministic property of TSI variability can provide information about future irradiation variability and expected long-term climate variation, whereas a non-deterministic variability can only explain the past.This study of solar variability is based on an analysis of two TSI data series, one since 1700 A.D. and one since 1000 A.D.; a sunspot data series since 1610 A.D.; and a solar orbit data series from 1000 A.D. The study is based on a wavelet spectrum analysis. First, the TSI data series are transformed into a wavelet spectrum. Then, the wavelet spectrum is transformed into an autocorrelation spectrum to identify stationary, subharmonic and coincidence periods in the TSI variability.The results indicate that the TSI and sunspot data series have periodic cycles that are correlated with the oscillations of the solar position relative to the barycenter of the solar system, which is controlled by gravity force variations from the large planets Jupiter, Saturn, Uranus and Neptune. A possible explanation for solar activity variations is forced oscillations between the large planets and the solar dynamo.We find that a stationary component of the solar variability is controlled by the 12-year Jupiter period and the 84-year Uranus period with subharmonics. For TSI and sunspot variations, we find stationary periods related to the 84-year Uranus period. Deterministic models based on the stationary periods confirm the results through a close relation to known long solar minima since 1000 A.D. and suggest a modern maximum period from 1940 to 2015. The model computes a new Dalton-type sunspot minimum from approximately 2025 to 2050 and a new Dalton-type period TSI minimum from approximately 2040 to 2065. 相似文献
10.
Periodic Appearance of Coronal Holes and the Related Variation of Solar Wind Parameters 总被引：1，自引：0，他引：1
We compared the variability of coronal hole (CH) areas (determined from daily GOES/SXI images) with solar wind (daily ACE
data) and geomagnetic parameters for the time span 25 January 2005 until 11 September 2005 (late declining phase of solar
cycle 23). Applying wavelet spectral analysis, a clear 9-day period is found in the CH time series. The GOES/SXI image sequence
suggests that this periodic variation is caused by a mutual triangular distribution of CHs ∼120° apart in longitude. From
solar wind parameters a 9-day periodicity was obtained as well, simultaneously with the 9-day period in the CH area time series.
These findings provide strong evidence that the 9-day period in solar wind parameters, showing up as higher harmonic of the
solar rotation frequency, is caused by the “periodic” longitudinal distribution of CHs on the Sun recurring for several solar
rotations. The shape of the wavelet spectrum from the Dst index matches only weakly with that from the CH areas and is more similar to the wavelet spectrum of the solar wind magnetic
field magnitude. The distinct 9-day period does not show up in sunspot group areas which gives further evidence that the solar
wind modulation is strongly related to CH areas but not to active region complexes. The wavelet power spectra for the whole
ACE data range (∼1998 – 2006) suggest that the 9-day period is not a singular phenomenon occurring only during a specific
time range close to solar minimum but is occasionally also present during the maximum and decay phase of solar cycle 23. The
main periods correspond to the solar rotation (27d) as well as to the second (13.5d) and third (9d) harmonic.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
11.
R. N. Bracewell 《Solar physics》1988,116(1):179-194
The Elatina formation in South Australia, which provides a rich fossil record of presumptive solar activity in the late Precambrian, is of great potential significance for the physics of the Sun because it contains laminae grouped in cycles of about 12, an appearance suggestive of the solar cycle. The actual spectrum of the lamina-thickness series is rather complex, 20 or more spectral lines having been recognized by Fourier analysis. It is shown how these numerous lines arise as combination frequencies, from a much simpler intrinsic spectrum, by rectification. Optical studies of the Sun have shown that there is a magnetic polarity reversal on the Sun every 11 years approximately, but terrestrial consequences of solar activity, for example in the ozonosphere or ionosphere, do not respond to solar magnetism; thus the negative-going semi-cycles of the full magnetic cycle are in effect rectified according to a linear law. Application of this knowledge to the Elatina formation shows that derectification simplifies the spectrum of the laminathickness series in exactly the way that one would expect if the solar cycle were at work here also. Zig-zag effect, an alternation of cycle thickness, is taken to be due, not to a beat phenomenon, but to rectification in the presence of a weak 345-year oscillation; subtraction of this oscillation after derectification is essential to the simplifying procedure. The fundamental period is established at a new sharper value of 23.7 ± 0.2 years as compared with the looser 22.2 ± 1.8 years for the modern sunspot series. This paper treats the laminae as varves laid down yearly and modulated in thickness in accordance with the late Precambrian sunspot activity for the year of deposition. Since the difference between 23.7 and 22.2 is less than a standard deviation it is premature to speculate that the sunspot cycle period has undergone secular change; indeed the possibility that the solar oscillator has been secularly stable is not ruled out. The high Q now demonstrated for the varve oscillator (around 120 compared with a previous value of 12) weakens support for that part of solar dynamo theory that ascribes the solar cycle to a self-sustaining relaxation osculation; conversely, the evidence for an internal solar clock mechanism is strenghtened. A wave propagation zone intervening between the clock and the solar surface could produce the intrinsic spectrum. 相似文献
12.
We study the solar cycle evolution during the last 8 solar cycles using a vectorial sunspot area called the LA (longitudinal asymmetry) parameter. This is a useful measure of solar activity in which the stochastic, longitudinally evenly distributed sunspot activity is reduced and which therefore emphasizes the more systematic, longitudinally asymmetric sunspot activity. Interesting differences are found between the LA parameter and the more conventional sunspot activity indices like the (scalar) sunspot area and the sunspot number. E.g., cycle 19 is not the highest cycle according to LA. We have calculated the separate LA parameters for the northern and southern hemisphere and found a systematic dipolar-type oscillation in the dominating hemisphere during high solar activity times which is reproduced from cycle to cycle. We have analyzed this oscillation during cycles 16–22 by a superposed epoch method using the date of magnetic reversal in the southern hemisphere as the zero epoch time. According to our analysis, the oscillation starts by an excess of the northern LA value in the ascending phase of the solar cycle which lasts for about 2.3 years. Soon after the maximum northern dominance, the southern hemisphere starts dominating, reaching its minimum some 1.2–1.7 years later. The period of southern dominance lasts for about 1.6 years and ends, on an average, slightly before the end of magnetic reversal. 相似文献
13.
Search for relationship between duration of the extended solar cycles and amplitude of sunspot cycle
A.G. Tlatov 《Astronomische Nachrichten》2007,328(10):1027-1029
Duration of the extended solar cycles is taken into the consideration. The beginning of cycles is counted from the moment of polarity reversal of large-scale magnetic field in high latitudes, occurring in the sunspot cycle n till the minimum of the cycle n + 2. The connection between cycle duration and its amplitude is established. Duration of the “latent” period of evolution of extended cycle between reversals and a minimum of the current sunspot cycle is entered. It is shown, that the latent period of cycles evolution is connected with the next sunspot cycle amplitude and can be used for the prognosis of a level and time of a sunspot maximum. The 24th activity cycle prognosis is made. The found dependences correspond to transport dynamo model of generation of solar cyclicity, it is possible with various speed of meridional circulation. Long-term behavior of extended cycle's lengths and connection with change of a climate of the Earth is considered. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
A hierarchy of cyclic changes in solar activity is studied based on energetic and phase wavelet analyses. The phase wavelet spectrum of yearly number of sunspot groups shows fork-like bifurcations. Separate 11-yr cycles are combined in pairs and wave trains to make up complete magnetic cycles with complex synergies. The phase spectrum also indicates the existence of different regimes in solar activity cyclic changes. This variability seems to be controlled by changes in the solar dynamo regime. 相似文献
15.
What the Sunspot Record Tells Us About Space Climate 总被引：1，自引：0，他引：1
The records concerning the number, sizes, and positions of sunspots provide a direct means of characterizing solar activity
over nearly 400 years. Sunspot numbers are strongly correlated with modern measures of solar activity including: 10.7-cm radio
flux, total irradiance, X-ray flares, sunspot area, the baseline level of geomagnetic activity, and the flux of galactic cosmic
rays. The Group Sunspot Number provides information on 27 sunspot cycles, far more than any of the modern measures of solar
activity, and enough to provide important details about long-term variations in solar activity or “Space Climate.” The sunspot
record shows: 1) sunspot cycles have periods of 131± 14 months with a normal distribution; 2) sunspot cycles are asymmetric
with a fast rise and slow decline; 3) the rise time from minimum to maximum decreases with cycle amplitude; 4) large amplitude
cycles are preceded by short period cycles; 5) large amplitude cycles are preceded by high minima; 6) although the two hemispheres
remain linked in phase, there are significant asymmetries in the activity in each hemisphere; 7) the rate at which the active
latitudes drift toward the equator is anti-correlated with the cycle period; 8) the rate at which the active latitudes drift
toward the equator is positively correlated with the amplitude of the cycle after the next; 9) there has been a significant
secular increase in the amplitudes of the sunspot cycles since the end of the Maunder Minimum (1715); and 10) there is weak
evidence for a quasi-periodic variation in the sunspot cycle amplitudes with a period of about 90 years. These characteristics
indicate that the next solar cycle should have a maximum smoothed sunspot number of about 145 ± 30 in 2010 while the following
cycle should have a maximum of about 70 ± 30 in 2023. 相似文献
16.
太阳和地磁活动中的1.3–1.7 yr周期研究对于理解日地空间耦合系统中可能发生的物理过程十分重要.黑子是太阳光球层上最突出的磁场结构, Ap指数则是表征全球地磁活动水平的重要指标.使用同步压缩小波变换得到太阳黑子数和地磁Ap指数的1.3–1.7yr周期,并用互相关方法分析研究它们之间的相位关系.结果如下:(1)太阳黑子数和地磁Ap指数的1.3–1.7 yr周期呈现间歇性的演化特征,且随着时间的变化而不断变化;(2)地磁Ap指数在奇数活动周比相邻的偶数活动周的周期分量更高,表现出上下波动的变化特性;(3)地磁Ap指数和太阳黑子数的相位关系不是一成不变的,在大多数情况下地磁Ap指数滞后太阳黑子数,仅在第18和第22活动周黑子数在相位上滞后. 相似文献
17.
The observed phase relations between the weak background solar magnetic (poloidal) field and strong magnetic field associated
with sunspots (toroidal field) measured at different latitudes are presented. For measurements of the solar magnetic field
(SMF) the low-resolution images obtained from Wilcox Solar Observatory are used and the sunspot magnetic field was taken from
the Solar Feature Catalogues utilizing the SOHO/MDI full-disk magnetograms. The quasi-3D latitudinal distributions of sunspot
areas and magnetic fields obtained for 30 latitudinal bands (15 in the northern hemisphere and 15 in the southern hemisphere)
within fixed longitudinal strips are correlated with those of the background SMF. The sunspot areas in all latitudinal zones
(averaged with a sliding one-year filter) reveal a strong positive correlation with the absolute SMF in the same zone appearing
first with a zero time lag and repeating with a two- to three-year lag through the whole period of observations. The residuals
of the sunspot areas averaged over one year and those over four years are also shown to have a well defined periodic structure
visible in every two – three years close to one-quarter cycle with the maxima occurring at − 40° and + 40° and drifts during
this period either toward the equator or the poles depending on the latitude of sunspot occurrence. This phase relation between
poloidal and toroidal field throughout the whole cycle is discussed in association with both the symmetric and asymmetric
components of the background SMF and relevant predictions by the solar dynamo models. 相似文献
18.
K. J. Li 《Solar physics》2009,255(1):169-177
Five solar-activity indices – the monthly-mean sunspot numbers from January 1945 to March 2008, the monthly-mean sunspot areas
during the period of May 1874 to March 2008, the monthly numbers of sunspot groups from May 1874 to May 2008, the monthly-mean
flare indices from January 1966 to December 2006, and the numbers of solar filaments per Carrington rotation in the time interval
of solar rotations 876 to 1823 – have been used to show a systematic time delay between northern and southern hemispheric
solar activities in a cycle. It is found that solar activity does not occur synchronously in the northern and southern hemispheres,
and there is a systematic time lag or lead (phase shift) between northern and southern hemispheric solar activity in a cycle.
About an eight-cycle period is inferred to exist in such phase shifts. The activity on the Sun may be governed by two different
and coupled processes, not by a single process. 相似文献
19.
We investigate the periodicity in the PMOD composite of the daily total solar irradiance (TSI) from 21 September 1978 to 9 June
2009. Besides the Schwabe cycle period (10.32 years), the quasi-rotation period is found to be statistically significant in
TSI, whose value is about 32 days, longer than that in sunspot activity (27 days), and it intermittently appears around the
sunspot maximum times. The quasi-rotation period in TSI is inferred to be mainly caused by sunspot activity, but to be modulated
by bright features as well. It was previously found that variations of TSI over a Schwabe solar cycle mainly come from the
combination of the sunspots’ blocking and the intensification due to bright faculae, plages, and network elements, with a
slight dominance of the bright-feature effect during the maximum of the Schwabe cycle. For the sunspot-blocking and the bright-feature
effect to contribute to TSI over a Schwabe solar cycle, the former is inferred to lead the latter by 29 days at least. 相似文献
20.
The morphological features of Pc5 pulsations during a solar cycle are studied using Fort Churchill data for the years 1962–1972. Some of the characteristics noted are as follows: (1) Increasing sunspot numbers show little influence on the diurnal variation of the occurrence, amplitude and the period except perhaps some noticeable change in the absolute magnitude of these parameters during different hours of the day. (2) The morning occurrence peak dominates during all phases of the solar cycle. (3) As noted earlier (Gupta 1973a), with increasing magnetic activity the day side region(s) of generation of Pc5 is found to shift closer to the subsolar point and in the midnight sector, the occurrence region (presumably the region of open and closed field lines) seemed to shift towards earlier hours with increasing magnetic activity and towards later hours with increasing sunspot numbers. (4) Despite the smaller number of data points for high magnetic activity levels the analysis indicates that the amplitude of Pc5 pulsations is directly related to all the levels of magnetic activity. (5) The periods of Pc5 pulsations show strong correlation with increasing sunspot numbers and the amplitude and occurrences are found to vary in accordance with the magnetic activity all through the cycle. (6) The annual and semi-annual variations of Pc5 parameters have been demonstrated especially for the pulsations occurring in the morning close to 8 ± 1 h LT and for those occurring near the midnight hours. (7) A suspected 27-day recurrence tendency has been clearly noticed for the occurrence, amplitude and period of Pc5 pulsations. 相似文献