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1.
In this work, the evolution of the relationship between Solar Cycle Length of solar cycle n (SCL
n
) and Solar Cycle Amplitude of the solar cycle n+1 (SCA
n+1) is studied by using the R
Z and R
G sunspot numbers. We conclude that this relationship is only strongly significant in a statistical sense during the first
half of the historical record of R
Z sunspot number whereas it is considerably less significant for the R
G sunspot number. In this sense we assert that these simple lagged relationships should be avoided as a valid method to predict
the following solar activity amplitude. 相似文献
2.
R. P. Kane 《Solar physics》2007,246(2):471-485
Many methods of predictions of sunspot maximum number use data before or at the preceding sunspot minimum to correlate with
the following sunspot maximum of the same cycle, which occurs a few years later. Kane and Trivedi (Solar Phys. 68, 135, 1980) found that correlations of R
z(max) (the maximum in the 12-month running means of sunspot number R
z) with R
z(min) (the minimum in the 12-month running means of sunspot number R
z) in the solar latitude belt 20° – 40°, particularly in the southern hemisphere, exceeded 0.6 and was still higher (0.86)
for the narrower belt > 30° S. Recently, Javaraiah (Mon. Not. Roy. Astron. Soc.
377, L34, 2007) studied the relationship of sunspot areas at different solar latitudes and reported correlations 0.95 – 0.97 between minima and maxima of sunspot areas at low latitudes
and sunspot maxima of the next cycle, and predictions could be made with an antecedence of more than 11 years. For the present
study, we selected another parameter, namely, SGN, the sunspot group number (irrespective of their areas) and found that SGN(min) during a sunspot minimum year at latitudes > 30° S had a correlation
+0.78±0.11 with the sunspot number R
z(max) of the same cycle. Also, the SGN during a sunspot minimum year in the latitude belt (10° – 30° N) had a correlation +0.87±0.07 with the
sunspot number R
z(max) of the next cycle. We obtain an appropriate regression equation, from which our prediction for the coming cycle 24 is R
z(max )=129.7±16.3. 相似文献
3.
A. G. Tlatov 《Astrophysics and Space Science》2009,323(3):221-224
The parameter G, which is determined from the general number of sunspots groups N
g
according to the daily observations G=∑(1/N
g
)2, is offered. This parameter is calculated for the days when there is at least one sunspots group. It characterizes the minimum
epoch solar activity. Parameter G mounts to the maximum during the epoch close to the minimal activity of sunspots. According to the data of the sequence of
sunspots group in Greenwich–USAF/NOAA observatory format, observation data of Kislovodsk solar station and also daily Wolf
number, the changes of parameter G during 100 years were reconstructed. It is demonstrated in the paper that parameter G’s amplitude in minimal solar activity n is linked with the sunspot cycle’s amplitude W
n+1 or one and half cycles. The 24th activity cycle prediction is calculated, which makes W
24=135(±12). 相似文献
4.
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
5.
J. Javaraiah 《Solar physics》2008,252(2):419-439
Recently, using Greenwich and Solar Optical Observing Network sunspot group data during the period 1874 – 2006, Javaraiah
(Mon. Not. Roy. Astron. Soc.
377, L34, 2007: Paper I), has found that: (1) the sum of the areas of the sunspot groups in 0° – 10° latitude interval of the Sun’s northern
hemisphere and in the time-interval of −1.35 year to +2.15 year from the time of the preceding minimum of a solar cycle n correlates well (corr. coeff. r=0.947) with the amplitude (maximum of the smoothed monthly sunspot number) of the next cycle n+1. (2) The sum of the areas of the spot groups in 0° – 10° latitude interval of the southern hemisphere and in the time-interval
of 1.0 year to 1.75 year just after the time of the maximum of the cycle n correlates very well (r=0.966) with the amplitude of cycle n+1. Using these relations, (1) and (2), the values 112±13 and 74±10, respectively, were predicted in Paper I for the amplitude
of the upcoming cycle 24. Here we found that the north – south asymmetries in the aforementioned area sums have a strong ≈44-year
periodicity and from this we can infer that the upcoming cycle 24 will be weaker than cycle 23. In case of (1), the north – south
asymmetry in the area sum of a cycle n also has a relationship, say (3), with the amplitude of cycle n+1, which is similar to (1) but more statistically significant (r=0.968) like (2). By using (3) it is possible to predict the amplitude of a cycle with a better accuracy by about 13 years
in advance, and we get 103±10 for the amplitude of the upcoming cycle 24. However, we found a similar but a more statistically
significant (r=0.983) relationship, say (4), by using the sum of the area sum used in (2) and the north – south difference used in (3).
By using (4) it is possible to predict the amplitude of a cycle by about 9 years in advance with a high accuracy and we get
87±7 for the amplitude of cycle 24, which is about 28% less than the amplitude of cycle 23. Our results also indicate that
cycle 25 will be stronger than cycle 24. The variations in the mean meridional motions of the spot groups during odd and even
numbered cycles suggest that the solar meridional flows may transport magnetic flux across the solar equator and potentially
responsible for all the above relationships.
The author did a major part of this work at the Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Los Angeles,
CA 90095-1547, USA. 相似文献
6.
David A. Juckett 《Solar physics》2010,262(1):3-17
Wolff (Astrophys. J.
193, 721, 1974) introduced the concept of g-mode coupling within the solar interior. Subsequently, Wolff developed a more quantitative model invoking a reciprocal interaction
between coupled g modes and burning in the solar core. Coupling is proposed to occur for constant values of the spherical harmonic degree [ℓ] creating rigidly rotating structures denoted as sets(ℓ). Power would be concentrated near the core and the top of radiative zone [RZ] in narrow intervals of longitude on opposite
sides of the Sun. Sets(ℓ) would migrate retrograde in the RZ as function of ℓ and their intersections would deposit extra energy at the top of the RZ. It is proposed that this enhances sunspot eruptions
at particular longitudes and at regular time intervals. Juckett and Wolff (Solar Phys.
252, 247, 2008) detected this enhancement by viewing selected spherical harmonics of sunspot patterns within stackplots twisted into the
relative rotational frames of various sets(ℓ). In subsequent work, the timings of the set(ℓ) intersections were compared to the sub-decadal variability of the sunspot cycle. Seventeen sub-decadal intersection frequencies
(0.63 – 7.0 year) were synchronous with 17 frequencies in the sunspot time-series with a mean correlation of 0.96. Six additional
non-11-year frequencies (periods of 8.0 to 28.7 year) are now shown to be nearly synchronous between sunspot variability and
the model. Two additional intersections have the same frequency as the solar cycle itself and peak during the rising phase
of the solar cycle. This may be partly responsible for cycle asymmetry. These results are evidence that some of the solar-cycle
variability may be attributable to deterministic components that are intermixed with a broad-spectrum stochastic and long-term
chaotic background. 相似文献
7.
R. P. Kane 《Solar physics》2007,243(2):205-217
For many purposes (e.g., satellite drag, operation of power grids on Earth, and satellite communication systems), predictions of the strength of
a solar cycle are needed. Predictions are made by using different methods, depending upon the characteristics of sunspot cycles.
However, the method most successful seems to be the precursor method by Ohl and his group, in which the geomagnetic activity
in the declining phase of a sunspot cycle is found to be well correlated with the sunspot maximum of the next cycle. In the
present communication, the method is illustrated by plotting the 12-month running means aa(min ) of the geomagnetic disturbance index aa near sunspot minimum versus the 12-month running means of the sunspot number Rz near sunspot maximum [aa(min ) versus Rz(max )], using data for sunspot cycles 9 – 18 to predict the Rz(max ) of cycle 19, using data for cycles 9 – 19 to predict Rz(max ) of cycle 20, and so on, and finally using data for cycles 9 – 23 to predict Rz(max ) of cycle 24, which is expected to occur in 2011 – 2012. The correlations were good (∼+0.90) and our preliminary predicted
Rz(max ) for cycle 24 is 142±24, though this can be regarded as an upper limit, since there are indications that solar minimum
may occur as late as March 2008. (Some workers have reported that the aa values before 1957 would have an error of 3 nT; if true, the revised estimate would be 124±26.) This result of the precursor
method is compared with several other predictions of cycle 24, which are in a very wide range (50 – 200), so that whatever
may be the final observed value, some method or other will be discredited, as happened in the case of cycle 23. 相似文献
8.
Zhanle Du 《Solar physics》2011,273(1):231-253
The shape of each sunspot cycle is found to be well described by a modified Gaussian function with four parameters: peak size
A, peak timing t
m, width B, and asymmetry α. The four-parameter function can be further reduced to a two-parameter function by assuming that B and α are quadratic functions of t
m, computed from the starting time (T
0). It is found that the shape can be better fitted by the four-parameter function, while the remaining behavior of the cycle
can be better predicted by the two-parameter function when using the data from a few (about two) months after the starting
time defined by the smoothed monthly mean sunspot numbers. As a new solar cycle is ongoing, its remaining behavior can be
constructed by the above four- or two-parameter function. A running test shows that the maximum amplitude of the cycle can
be predicted to within 15% at about 25 months into the cycle based on the two-parameter function. A preliminary modeling to
the first 24 months of data available for the current cycle indicates that the peak of cycle 24 may probably occur around
June 2013±7 months with a size of 72±11. The above results are compared to those by quasi-Planck functions. 相似文献
9.
Smoothed monthly mean Ap indices are decomposed into two components (Ap)
c and (Ap)
n. The former is directly correlated with the current sunspot numbers, while the latter is shown to achieve its maximum correlation with the sunspot numbers after some time lag. This latter property is used to develop a method for predicting the sunspot maximum based on the observed value of (Ap)
n maximum which occurs during the preceding cycle. The value of R
M for cycle 23 predicted by this method is 149.3 ± 19.9. A method to estimate the rise time (from solar minimum to maximum) has been developed (based on analyses of Hathaway, Wilson, and Reichmann, 1994) and yields a value of 4.2 years. Using an estimate that the minimum between cycles 22 and 23 occurred in May 1996, it is predicted that the sunspot maximum for cycle 23 will occur in July 2000. 相似文献
10.
Markus J. Aschwanden 《Solar physics》2011,274(1-2):99-117
We analyze the occurrence-frequency distributions of peak fluxes [P], total fluxes [E], and durations [T] of solar flares over the last three solar cycles (during 1980??C?2010) from SMM/HXRBS, CGRO/BATSE, and RHESSI hard X-ray data. From the synthesized data we find powerlaw slopes with mean values of ?? P =1.73±0.07 for the peak flux, ?? E =1.62±0.12 for the total flux, and ?? T =1.99±0.35 for flare durations. We find a tendency of an anti-correlation of the powerlaw slope of peak fluxes with the flare rate or sunspot number as a function of the solar cycle. The occurrence powerlaw slope is always steeper by ??????0.1 during a solar-cycle minimum compared with the previous solar-cycle maximum, but the relative amplitude varies for each cycle or instrument. Since each solar cycle has been observed with a different instrument, part of the variation could be attributed to instrumental characteristics and different event selection criteria used in generating the event catalogs. The relatively flatter powerlaw slopes during solar maxima could indicate more energetic flares with harder electron-energy spectra, probably due to a higher magnetic complexity of the solar corona. This would imply a non-stationarity (or solar-cycle dependence) of the coronal state of self-organized criticality. 相似文献
11.
Results are presented from a study of various sunspot contrast parameters in broadband red (672.3 nm) Cartesian full-disk
digital images taken at the San Fernando Observatory (SFO) over eight years, 1997 – 2004, of the twenty-third sunspot cycle.
A subset of over 2700 red sunspots was analyzed and values of average and maximum sunspot contrast as well as maximum umbral
contrast were compared to various sunspot parameters. Average and maximum sunspot contrasts were found to be significantly
correlated with sunspot area (r
s=− 0.623 and r
s=− 0.714, respectively). Maximum umbral contrast was found to be significantly correlated with umbral area (r
s=− 0.535). These results are in agreement with the works of numerous other authors. No significant dependence was detected
between average contrast, maximum contrast, or maximum umbral contrast during the rising phase of the solar cycle (r
s=0.024, r
s=0.033, and r
s=0.064, respectively). During the decay phase, no significant correlation was found between average contrast or maximum contrast
and time (r
s=− 0.057 and r
s=0.009, respectively), with a weak dependence seen between maximum umbral contrast and cycle (r
s=0.102). 相似文献
12.
This paper investigates a series of daily solar indices: the sunspot number W (1900–2008), solar flux at 2800 MHz F
10.7 (1947–2008), and a number of X-ray flares N
x
(1981–2008). The methods of Fourier and wavelet analysis are used to reveal the so-called 156-day Rieger-type periodicity
(RTP). The W index is observed to have a statistically significant RTP amplitude in the neighborhood of the solar maxima in most of the
solar cycles under study, except for cycles 14, 15, and 23. The 156-day peak is observed to have its largest power during
the declining phase of cycle 16, at the maximum of cycle 21, and during the increasing phase of cycles 20 and 23. Statistically
significant RTPs are also observed at the minima of cycles 17, 18 and 19. We conclude that there is no stable dependence between
RTP and the solar cycle. The wavelet analysis shows that the pattern of the RTP time dependence for the F
10.7 index is almost identical to that of the W index. The correlation coefficient between the RTP curves is 0.95. The correlation coefficients for the pairs of indices
W-N
x
and F
10.7-N
x
are 0.36 and 0.32, respectively. No time lags are found between the RTP starting points for different indices. Thus, the
156-day quasi-periodicity involves, almost simultaneously, events that occur in active regions of the solar atmosphere at
different heights. This paper discusses the possible nature of RTP. 相似文献
13.
R. P. Kane 《Solar physics》2006,233(1):107-115
This paper examines the variations of coronal mass ejections (CMEs) and interplanetary CMEs (ICMEs) during solar cycle 23
and compares these with those of several other indices. During cycle 23, solar and interplanetary parameters had an increase
from 1996 (sunspot minimum) to ∼2000, but the interval 1998–2002 had short-term fluctuations. Sunspot numbers had peaks in
1998, 1999, 2000 (largest), 2001 (second largest), and 2002. Other solar indices had matching peaks, but the peak in 2000
was larger than the peak in 2001 only for a few indices, and smaller or equal for other solar indices. The solar open magnetic
flux had very different characteristics for different solar latitudes. The high solar latitudes (45∘–90∘) in both N and S hemispheres had flux evolutions anti-parallel to sunspot activity. Fluxes in low solar latitudes (0∘–45∘) evolved roughly parallel to sunspot activity, but the finer structures (peaks etc. during sunspot maximum years) did not
match with sunspot peaks. Also, the low latitude fluxes had considerable N–S asymmetry. For CMEs and ICMEs, there were increases
similar to sunspots during 1996–2000, and during 2000–2002, there was good matching of peaks. But the peaks in 2000 and 2001
for CMEs and ICMEs had similar sizes, in contrast to the 2000 peak being greater than the 2001 peak for sunspots. Whereas
ICMEs started decreasing from 2001 onwards, CMEs continued to remain high in 2002, probably due to extra contribution from
high-latitude prominences, which had no equivalent interplanetary ICMEs or shocks. Cosmic ray intensity had features matching
with those of sunspots during 2000–2001, with the 2000 peak (on a reverse scale, actually a cosmic ray decrease or trough)
larger than the 2001 peak. However, cosmic ray decreases started with a delay and ended with a delay with respect to sunspot
activity. 相似文献
14.
Comet outburst activity and the structure of solar wind streams were compared on the basis of Pioneer 10, 11, Vela 3 and IMP
7, 8 measurements at the heliocentric distance r ≈ 1–6 AU. It is shown that the solar wind velocity waves which are evolving into corotating shock waves beyond the Earth
orbit may be responsible for comet outburst activity. The correlation between variations of comet outburst activity with heliocentric
distance and the behavior of the solar wind velocity waves is established. The closeness of the characteristic times for the
velocity waves and comet outburst activity (7–8 days at r = 1 AU) as well as the simultaneous growth of both the characteristic times with r are noted. The observed distribution of the comet outburst activity parameters during the 11-year cycle is also in good agreement
with the phase distributions during the 11-year cycle of variations of the coronal hole areas and the rate of change of the
sunspot area δS
p. 相似文献
15.
K. F. Tapping D. Boteler P. Charbonneau A. Crouch A. Manson H. Paquette 《Solar physics》2007,246(2):309-326
We develop a model for estimating solar total irradiance since 1600 AD using the sunspot number record as input, since this
is the only intrinsic record of solar activity extending back far enough in time. Sunspot number is strongly correlated, albeit
nonlinearly with the 10.7-cm radio flux (F
10.7), which forms a continuous record back to 1947. This enables the nonlinear relationship to be estimated with usable accuracy
and shows that relationship to be consistent over multiple solar activity cycles. From the sunspot number record we estimate
F
10.7 values back to 1600 AD. F
10.7 is linearly correlated with the total amount of magnetic flux in active regions, and we use it as input to a simple cascade
model for the other magnetic flux components. The irradiance record is estimated by using these magnetic flux components plus
a very rudimentary model for the modulation of energy flow to the photosphere by the subphotospheric magnetic flux reservoir
feeding the photospheric magnetic structures. Including a Monte Carlo analysis of the consequences of measurement and fitting
errors, the model indicates the mean irradiance during the Maunder Minimum was about 1 ± 0.4 W m−2 lower than the mean irradiance over the last solar activity cycle. 相似文献
16.
The photometrical flattening index of the solar corona a+b is defined according to Ludendorff. In this paper we have investigated how the flattening index varies with respect to the
phase of solar activity and the sunspot number. We have compiled 170 values of the flattening index using the data on 60 total
solar eclipses from 1851 to 2010. We have found that the flattening index takes values from 0 to 0.4, and is anticorrelated
with solar activity. The value of the flattening index at the beginning of solar cycle 24 was used as a precursor to forecast
the amplitude of the cycle. It was found that the amplitude of solar cycle 24 will be about 95 in terms of the smoothed monthly
sunspot numbers. 相似文献
17.
We study the evolution of the longitudinal asymmetry in solar activity through the wave packet technique applied to the period
domain of 25 – 31 days (centered at the 27-day solar rotation period) for the sunspot number and geomagnetic aa index. We observe the occurrence of alternating smaller and larger amplitudes of the 11-year cycle, resulting in a 22-year
periodicity in the 27-day signal. The evolution of the 22-year cycle shows a change of regime around the year 1912 when the
22-year period disappears from the sunspot number series and appears in the aa index. Other changes, such as a change in the correlation between solar and geomagnetic activity, took place at the same
time. Splitting the 27-day frequency domain of aa index shows an 11-year cycle for higher frequencies and a pure22-year cycle for lower frequencies, which we attribute to
higher latitude coronal holes. This evidence is particularly clear after 1940, which is another benchmark in the evolution
of the aa index. We discuss briefly the mechanisms that could account for the observed features of the 22-year cycle evolution. 相似文献
18.
Robert M. Wilson 《Solar physics》1988,117(1):179-186
Examined are associational aspects as they relate the maximum amplitude R
M
for the sunspot cycle to the rate of rise R
t
during the ascending phase, where R
M
is the smoothed sunspot number at cycle maximum and R
t
is the sum of the monthly mean sunspot numbers for selected 6-month intervals (t) measured from cycle onset. One finds that, prior to about 2 yr into the cycle, the rate of rise is not a reliable predictor for maximum amplitude. Only during the latter half of the ascent do the fits display strong linearity, having a coefficient of correlation r 0.9 and a standard error S
yx
20. During the first four intervals, the expected R
M
and the observed R
M
were found to differ by no more than 20 units of smoothed sunspot number only 25, 42, 50, and 58 % of the time; during the latter four intervals, they differed by no more than 20 units 67, 83, 92, and 100% of the time. 相似文献
19.
Yu. A. Nagovitsyn 《Astronomy Letters》2007,33(5):340-345
We have obtained new consistent versions of the 400-yr time series of the Wolf sunspot number W, the sunspot group number G, and the total sunspot area S (or the total sunspot magnetic flux Φ). We show that the 11-yr cycle did not cease during the Maunder minimum of solar activity. The characteristics of the extrema of individual 11-yr cycles in 1600–2005 have been determined in terms of the total sunspot area index. We provide arguments for using alternating (“magnetic”) time series of indices in investigating the solar cyclicity. 相似文献
20.
During solar cycle 23, 82 interplanetary magnetic clouds (MCs) were identified by the Magnetic Field Investigation (MFI) team
using Wind (1995 – 2003) solar wind plasma and magnetic field data from solar minimum through the maximum of cycle 23. The average occurrence
rate is 9.5 MCs per year for the overall period. It is found that some of the anomalies in the frequency of occurrence were
during the early part of solar cycle 23: (i) only four MCs were observed in 1999, and (ii) an unusually large number of MCs
(17 events) were observed in 1997, just after solar minimum. We also discuss the relationship between MCs, coronal mass ejections
(CMEs), and geomagnetic storms. During the period 1996 – 2003, almost 8000 CMEs were observed by SOHO-LASCO. The occurrence
frequency of MCs appears to be related neither to the occurrence of CMEs as observed by SOHO LASCO nor to the sunspot number.
When we included “magnetic cloud-like structures” (MCLs, defined by Lepping, Wu, and Berdichevsky, 2005), we found that the
occurrence of the joint set (MCs + MCLs) is correlated with both sunspot number and the occurrence rate of CMEs. The average
duration of the MCL structures is ~40% shorter than that of the MCs. The MCs are typically more geoeffective than the MCLs,
because the average southward field component is generally stronger and longer lasting in MCs than in MCLs. In addition, most
severe storms caused by MCs/MCLs with Dst
min≤ −100 nT occurred in the active solar period. 相似文献