scholarly journals On the Prediction of Solar Cycles

Solar Physics ◽  
2021 ◽  
Vol 296 (1) ◽  
Author(s):  
V. Courtillot ◽  
F. Lopes ◽  
J. L. Le Mouël
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Transfer Function ◽  
Singular Spectrum Analysis ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Planetary Motion ◽  
Data Sets ◽  
Solar Cycles ◽  
Jovian Planets

AbstractThis article deals with the prediction of the upcoming solar activity cycle, Solar Cycle 25. We propose that astronomical ephemeris, specifically taken from the catalogs of aphelia of the four Jovian planets, could be drivers of variations in solar activity, represented by the series of sunspot numbers (SSN) from 1749 to 2020. We use singular spectrum analysis (SSA) to associate components with similar periods in the ephemeris and SSN. We determine the transfer function between the two data sets. We improve the match in successive steps: first with Jupiter only, then with the four Jovian planets and finally including commensurable periods of pairs and pairs of pairs of the Jovian planets (following Mörth and Schlamminger in Planetary Motion, Sunspots and Climate, Solar-Terrestrial Influences on Weather and Climate, 193, 1979). The transfer function can be applied to the ephemeris to predict future cycles. We test this with success using the “hindcast prediction” of Solar Cycles 21 to 24, using only data preceding these cycles, and by analyzing separately two 130 and 140 year-long halves of the original series. We conclude with a prediction of Solar Cycle 25 that can be compared to a dozen predictions by other authors: the maximum would occur in 2026.2 (± 1 yr) and reach an amplitude of 97.6 (± 7.8), similar to that of Solar Cycle 24, therefore sketching a new “Modern minimum”, following the Dalton and Gleissberg minima.

SOLAR NEUTRINO FLUX VARIATION IN KAMIOKANDE DETECTOR DURING SOLAR CYCLE 22

1998 ◽  
Vol 13 (14) ◽  
pp. 1109-1114 ◽  
Author(s):  
PROBHAS RAYCHAUDHURI
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Solar Neutrino ◽  
Neutrino Flux ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Solar Cycles ◽  
Flux Data ◽  
Solar Neutrino Flux ◽  
Five Phases

The 8 B solar neutrino flux observed in Kamiokande detector (KAMIOKANDE II and III) from January 1987 to February 1995 has been analysed statistically and it has been found that solar neutrino flux data in Kamiokande detector varies with the solar activity cycle. It is also shown that solar neutrino flux data in Kamiokande detector also has five phases during the solar cycle 22 as observed in the Homestake solar neutrino flux data during the solar cycles 21 and 22 indicating that the solar activity cycle is due to the pulsating character of the nuclear energy generation inside the core of the sun.

scholarly journals Breathing of heliospheric structures triggered by the solar-cycle activity

2003 ◽  
Vol 21 (6) ◽  
pp. 1303-1313 ◽  
Author(s):  
K. Scherer ◽  
H. J. Fahr
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Solar Cycle ◽  
Activity Cycle ◽  
Periodic Variation ◽  
Galactic Cosmic Rays ◽  
Activity Period ◽  
Solar Cycles ◽  
Interplanetary Physics ◽  
Ram Pressure

Abstract. Solar wind ram pressure variations occuring within the solar activity cycle are communicated to the outer heliosphere as complicated time-variabilities, but repeating its typical form with the activity period of about 11 years. At outer heliospheric regions, the main surviving solar cycle feature is a periodic variation of the solar wind dynamical pressure or momentum flow, as clearly recognized by observations of the VOYAGER-1/2 space probes. This long-periodic variation of the solar wind dynamical pressure is modeled here through application of appropriately time-dependent inner boundary conditions within our multifluid code to describe the solar wind – interstellar medium interaction. As we can show, it takes several solar cycles until the heliospheric structures adapt to an average location about which they carry out a periodic breathing, however, lagged in phase with respect to the solar cycle. The dynamically active heliosphere behaves differently from a static heliosphere and especially shows a historic hysteresis in the sense that the shock structures move out to larger distances than explained by the average ram pressure. Obviously, additional energies are pumped into the heliosheath by means of density and pressure waves which are excited. These waves travel outwards through the interface from the termination shock towards the bow shock. Depending on longitude, the heliospheric sheath region memorizes 2–3 (upwind) and up to 6–7 (downwind) preceding solar activity cycles, i.e. the cycle-induced waves need corresponding travel times for the passage over the heliosheath. Within our multifluid code we also adequately describe the solar cycle variations in the energy distributions of anomalous and galactic cosmic rays, respectively. According to these results the distribution of these high energetic species cannot be correctly described on the basis of the actually prevailing solar wind conditions.Key words. Interplanetary physics (heliopause and solar wind termination; general or miscellaneous) – Space plasma physics (experimental and mathematical techniques)

Solar Cycle Graphics 1700–1988 AD

1990 ◽  
Vol 8 (3) ◽  
pp. 298-302 ◽  
Author(s):  
J. O. Murphy
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Mean Values ◽  
Low Pass ◽  
Band Pass ◽  
Filtering Techniques

AbstractA graphical format has been adopted to depict some characteristic variations associated with the solar activity cycle up to 1988, for both the Zurich annual and monthly mean values over the respective periods from 1700 and 1750. Both low pass and band pass filtering techniques have been employed to smooth the data, the autocorrelation coefficients determined for a high number of lags to illustrate the secular modulation of the maximum values in each cycle and the spectral amplitudes computed to establish periodicities in the chronologies.

scholarly journals Time-Latitude Prominence and the Green Corona Distribution Over the Solar Activity Cycle

1998 ◽  
Vol 167 ◽  
pp. 484-487 ◽  
Author(s):  
M. Minarovjech ◽  
M. Rybanský ◽  
V. Rušin
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
High Latitude ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
North Pole ◽  
Latitudinal Distribution ◽  
The South ◽  
The North

AbstractWe present a distribution of prominences over the solar cycle activity. There are found both polar and equatorial branches of prominences that migrate in opposite directions. Prominences of the high-latitude crown migrate, starting in the minimum of the cycle, towards the poles, which they reach at the maximum of the cycle and then decay. The equatorward-migrating branch of prominences appears also in the minimum of the cycle at mid-latitudes and disappears at the end of the cycle. The distribution of the prominences is compared with a time-latitudinal distribution of the green corona. It is assumed that the polar branches in cycle 23 will reach the poles in 2002 (the north pole) and 2003 (the south one), respectively.

A search for north-south asymmetry of interplanetary magnetic field and solar plasma

1994 ◽  
Vol 12 (4) ◽  
pp. 279-285 ◽  
Author(s):  
I. Sabbah
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Solar Cycle ◽  
Interplanetary Magnetic Field ◽  
Current Sheet ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Negative Polarity ◽  
Solar Plasma ◽  
Spiral Angle

Abstract. An analysis of interplanetary magnetic field (IMF) and plasma data taken near 1 AU during solar activity cycle 21 reveals the following. 1. The yearly averaged spiral angle shows a solar cycle dependence. 2. The spiral angle north of the current sheet is 2.4° higher than south of it during both epochs of positive and negative polarities. 3. The included angle is 4.8° higher during the epoch of positive polarity than during the epoch of negative polarity. 4. The asymmetries in the number of away and toward IMF days are correlated with the asymmetries in solar activity. 5. The solar plasma north of the current sheet is hotter, faster and less dense than south of it during the epoch of negative polarity. 6. An asymmetry in the averaged filed magnitude is absent for solar cycle 21.

scholarly journals Variations of the Low l Solar Acoustic Spectrum Correlated with the Activity Cycle

1990 ◽  
Vol 121 ◽  
pp. 349-355 ◽  
Author(s):  
P.L. Pallé ◽  
C. Régulo ◽  
T. Roca Cortés
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Cross Correlation ◽  
Power Spectra ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Frequency Variation ◽  
Acoustic Oscillations ◽  
Solar Cycle Variation ◽  
The Cross

AbstractSolar cycle variation of the frequencies and of the power of solar acoustic oscillations are investigated. Integrated sunlight data from 1977 to 1988 obtained at the Observatorio del Teide (Izaña, Tenerife), using a resonant scattering spectrophotometer, is analyzed in 60 day time strings and their power spectra are calculated from 2 to 3.8 mHz. To study the frequency variation, each power spectrum is cross-correlated with the one corresponding to the 1981 series and the shifts of the centroids of the cross-correlation peaks are calculated. The results show a clear variation in frequency of the cross-correlation peaks of −0.37 ± 0.04 μHz peak to peak as solar activity cycle goes from maximum to minimum. Moreover, this effect is found to depend on the l value of the modes, being absent for l = 0 and of 0.42 ± 0.06 μHz for l = 1. These results can be interpreted as an amplitude modulation between modes of the same multiplet, probably as a consequence of the action of strong magnetic fields. As low l modes penetrate deeply into the Sun’s interior, these observations suggest changes in its structure correlated with the solar activity cycle. When the power of the modes is calculated, using the same series as before, and its change along the solar cycle is studied, a variation of ~ 40% is found, the power being higher when solar activity is at its minimum. If this effect is independent of the l value of the p-modes, the results can be interpreted in terms of a change in the efficiency of the excitation mechanism of such modes. Indeed, if turbulent convection is such a mechanism, a change in the characteristic size of the granulation would account for the observed effect. Alternatively, another explanation could be a selective change in the efficiency of the excitation and/or damping mechanisms of the l ≤ 3 modes in front of other l value modes.

Solar-Cycle variation in the photospheric mean velocity flows: GONG observations

2018 ◽  
Vol 13 (S340) ◽  
pp. 59-60
Author(s):  
Brajesh Kumar
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Solar Disk ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Doppler Imaging ◽  
The Sun ◽  
Mean Velocity ◽  
Solar Cycle Variation ◽  
Global Oscillation Network Group

AbstractThe solar oscillation frequencies have shown variation over the solar activity cycle, which is believed to be the indicator of the structural and magnetic changes taking place in the Sun. The ground-based network of six identical solar telescopes in the Global Oscillation Network Group (GONG) program has been nearly-continuously observing the Sun since the last quarter of the year 1995 for Doppler imaging of the solar-disk aimed to study the oscillations and velocity flows on the surface of the Sun. In this work, we study the variations in the solar disk-integrated mean velocity flows on the solar surface as observed with the GONG over the complete Solar Cycle 23 and ongoing Cycle 24. The correlation analysis of these solar photospheric mean velocity flows relative to the various solar activity indicators is also discussed.

scholarly journals Solar-cycle irradiance variations over the last four billion years

2020 ◽  
Vol 636 ◽  
pp. A83 ◽  
Author(s):  
Anna V. Shapiro ◽  
Alexander I. Shapiro ◽  
Laurent Gizon ◽  
Natalie A. Krivova ◽  
Sami K. Solanki
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Solar Irradiance ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Magnetic Activity ◽  
The Sun ◽  
Earth’S Atmosphere ◽  
Solar Magnetic Activity ◽  
Earth's Atmosphere

Context. The variability of the spectral solar irradiance (SSI) over the course of the 11-year solar cycle is one of the manifestations of solar magnetic activity. There is strong evidence that the SSI variability has an effect on the Earth’s atmosphere. The faster rotation of the Sun in the past lead to a more vigorous action of solar dynamo and thus potentially to larger amplitude of the SSI variability on the timescale of the solar activity cycle. This could lead to a stronger response of the Earth’s atmosphere as well as other solar system planets’ atmospheres to the solar activity cycle. Aims. We calculate the amplitude of the SSI and total solar irradiance (TSI) variability over the course of the solar activity cycle as a function of solar age. Methods. We employed the relationship between the stellar magnetic activity and the age based on observations of solar twins. Using this relation, we reconstructed solar magnetic activity and the corresponding solar disk area coverages by magnetic features (i.e., spots and faculae) over the last four billion years. These disk coverages were then used to calculate the amplitude of the solar-cycle SSI variability as a function of wavelength and solar age. Results. Our calculations show that the young Sun was significantly more variable than the present Sun. The amplitude of the solar-cycle TSI variability of the 600 Myr old Sun was about ten times larger than that of the present Sun. Furthermore, the variability of the young Sun was spot-dominated (the Sun being brighter at the activity minimum than in the maximum), that is, the Sun was overall brighter at activity minima than at maxima. The amplitude of the TSI variability decreased with solar age until it reached a minimum value at 2.8 Gyr. After this point, the TSI variability is faculae-dominated (the Sun is brighter at the activity maximum) and its amplitude increases with age.

scholarly journals Forecasting the solar activity cycle: new insights

2012 ◽  
Vol 8 (S294) ◽  
pp. 439-444 ◽  
Author(s):  
Dibyendu Nandy ◽  
Bidya Binay Karak
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Solar Interior ◽  
Solar Dynamo ◽  
Term Prediction ◽  
Dynamo Mechanism ◽  
Short Term Prediction ◽  
Long Term Prediction

AbstractHaving advance knowledge of solar activity is important because the Sun's magnetic output governs space weather and impacts technologies reliant on space. However, the irregular nature of the solar cycle makes solar activity predictions a challenging task. This is best achieved through appropriately constrained solar dynamo simulations and as such the first step towards predictions is to understand the underlying physics of the solar dynamo mechanism. In Babcock-Leighton type dynamo models, the poloidal field is generated near the solar surface whereas the toroidal field is generated in the solar interior. Therefore a finite time is necessary for the coupling of the spatially segregated source layers of the dynamo. This time delay introduces a memory in the dynamo mechanism which allows forecasting of future solar activity. Here we discuss how this forecasting ability of the solar cycle is affected by downward turbulent pumping of magnetic flux. With significant turbulent pumping the memory of the dynamo is severely degraded and thus long term prediction of the solar cycle is not possible; only a short term prediction of the next cycle peak may be possible based on observational data assimilation at the previous cycle minimum.

scholarly journals THE SOLAR ACTIVITY CYCLES AND THE OUTBREAKS OF THE GYPSY MOTH – LYMANTRIA DISPAR L. (LEPIDOPTERA: LYMANTRIIDAE) IN SERBIA

2016 ◽  
Vol 7 ◽  
pp. 538-545
Author(s):  
Milan Milenković ◽  
Vladan Ducić
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Solar Flux ◽  
Activity Cycles ◽  
In The Beginning ◽  
Solar Activity Cycles

Seven outbreaks of the gypsy moth in Serbia for the last seven decades were researched in relation to the solar activity cycles and the solar flux at 2.8 GHz. Based on data analysis, three types of outbreaks were selected. A–type includes the second half of the solar cycle. This type of the outbreak doesn’t get into the next cycle (the values of the solar flux at 2.8 GHz decrease in the final phases). Besides the final years of the solar cycle, B–type also includes the initial years of the next cycle. C–type appears in the beginning of the solar activity cycle. At B-type and C-type the interruption of the outbreak occurs while the solar flux at 2.8 GHz value is increasing. The outbreaks of A-type were: 1970–1976 and 2004–2007; B-type: 1952–1956, 1962–1966, 1984–1987 and 1995–1998; C-type: 2009–2014. The obtained results suggest that the gypsy moth outbreaks are caused by corresponding range of energy coming from the Sun.

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