scholarly journals Gradual onset of the Maunder Minimum revealed by high-precision carbon-14 analyses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroko Miyahara ◽  
Fuyuki Tokanai ◽  
Toru Moriya ◽  
Mirei Takeyama ◽  
Hirohisa Sakurai ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
High Precision ◽  
Crop Yields ◽  
Maunder Minimum ◽  
The Sun ◽  
Solar Cycles ◽  
Precision Data ◽  
Carbon 14 ◽  
Grand Minimum

AbstractThe Sun exhibits centennial-scale activity variations and sometimes encounters grand solar minimum when solar activity becomes extremely weak and sunspots disappear for several decades. Such an extreme weakening of solar activity could cause severe climate, causing massive reductions in crop yields in some regions. During the past decade, the Sun’s activity has tended to decline, raising concerns that the Sun might be heading for the next grand minimum. However, we still have an underdeveloped understanding of solar dynamo mechanisms and hence precise prediction of near-future solar activity is not attained. Here we show that the 11-year solar cycles were significantly lengthened before the onset of the Maunder Minimum (1645–1715 CE) based on unprecedentedly high-precision data of carbon-14 content in tree rings. It implies that flow speed in the convection zone is an essential parameter to determine long-term solar activity variations. We find that a 16 year-long cycle had occurred three solar cycles before the onset of prolonged sunspot disappearance, suggesting a longer-than-expected preparatory period for the grand minimum. As the Sun has shown a tendency of cycle lengthening since Solar Cycle 23 (1996–2008 CE), the behavior of Solar Cycle 25 can be critically important to the later solar activity.

ESTABLISHING SOLAR ACTIVITY TREND FOR SOLAR CYCLES 21 – 24

2021 ◽  
Vol 44 ◽  
pp. 100-106
Author(s):  
A.K. Singh ◽  
◽  
A. Bhargawa ◽  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Sunspot Number ◽  
Cosmic Ray ◽  
Occurrence Rate ◽  
The Sun ◽  
Solar Cycles ◽  
Lyman Alpha ◽  
Rate Versus ◽  
Alpha Index

Solar-terrestrial environment is manifested primarily by the physical conditions of solar interior, solar atmosphere and eruptive solar plasma. Each parameter gives unique information about the Sun and its activity according to its defined characteristics. Hence the variability of solar parameters is of interest from the point of view of plasma dynamics on the Sun and in the interplanetary space as well as for the solar-terrestrial physics. In this study, we have analysed various solar transients and parameters to establish the recent trends of solar activity during solar cycles 21, 22, 23 and 24. The correlation coefficients of linear regression of F10.7 cm index, Lyman alpha index, Mg II index, cosmic ray intensity, number of M & X class flares and coronal mass ejections (CMEs) occurrence rate versus sunspot number was examined for last four solar cycles. A running cross-correlation method has been used to study the momentary relationship among the above mentioned solar activity parameters. Solar cycle 21 witnessed the highest value of correlation for F10.7 cm index, Lyman alpha index and number of M-class and X-class flares versus sunspot number among all the considered solar cycles which were 0.979, 0.935 and 0.964 respectively. Solar cycle 22 recorded the highest correlation in case of Mg II index, Ap index and CMEs occurrence rate versus sunspot number among all the considered solar cycles (0.964, 0.384 and 0.972 respectively). Solar cycle 23 and 24 did not witness any highest correlation compared to solar cycle 21 and 22. Further the record values (highest value compared to other solar three cycles) of each solar activity parameters for each of the four solar cycles have been studied. Here solar cycle 24 has no record text at all, this simply indicating that this cycle was a weakest cycle compared to the three previous ones. We have concluded that in every domain solar 24 was weaker to its three predecessors.

scholarly journals Complexes of activity on the Sun in solar cycle 21

2021 ◽  
pp. 3-9
Author(s):  
Sergey Yazev ◽  
Maria Ulianova ◽  
Elena Isaeva
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Natural Environment ◽  
Statistical Data ◽  
Sunspot Activity ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
South Asymmetry

The paper provides statistical data on solar activity complexes (ACs) observed in solar cycle 21. From the synoptic charts for the 1976–1986 sunspot activity, we have detected the regions where the sunspot generation was observed at least through three Carrington Rotations (CRs). These regions were identified as AC cores. We have compiled an AC catalogue. ACs are shown to evolve quasi-periodically, in pulses that are 15–20 rotations long. We have analyzed the North-South asymmetry in the AC location. In cycle 21, 90 % of the proton flares that affected the natural environment are shown to have occurred in ACs. We note a tendency for AC activity to decrease, as well as the manifestation of the Gnevyshev—Ohl rule in AC properties, in solar cycles 21–24.

scholarly journals Complexes of activity on the Sun in solar cycle 21

2021 ◽  
Vol 7 (4) ◽  
pp. 3-9
Author(s):  
Sergey Yazev ◽  
Maria Ulianova ◽  
Elena Isaeva
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Natural Environment ◽  
Statistical Data ◽  
Sunspot Activity ◽  
The Sun ◽  
Solar Cycles ◽  
The North ◽  
South Asymmetry

The paper provides statistical data on solar activity complexes (ACs) observed in solar cycle 21. From the synoptic charts for the 1976–1986 sunspot activity, we have detected the regions where the sunspot generation was observed at least through three Carrington Rotations (CRs). These regions were identified as AC cores. We have compiled an AC catalogue. ACs are shown to evolve quasi-periodically, in pulses that are 15–20 rotations long. We have analyzed the North-South asymmetry in the AC location. In cycle 21, 90 % of the proton flares that affected the natural environment are shown to have occurred in ACs. We note a tendency for AC activity to decrease, as well as the manifestation of the Gnevyshev—Ohl rule in AC properties, in solar cycles 21–24.

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.

scholarly journals A review of the SCOSTEP’s 5-year scientific program VarSITI—Variability of the Sun and Its Terrestrial Impact

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kazuo Shiokawa ◽  
Katya Georgieva
Keyword(s):  
Solar Wind ◽  
Interplanetary Space ◽  
Solar Wind Plasma ◽  
The Sun ◽  
Scientific Program ◽  
Solar Cycles ◽  
Grand Minimum ◽  
The Earth ◽  
Earth Connection ◽  
Near Future

AbstractThe Sun is a variable active-dynamo star, emitting radiation in all wavelengths and solar-wind plasma to the interplanetary space. The Earth is immersed in this radiation and solar wind, showing various responses in geospace and atmosphere. This Sun–Earth connection variates in time scales from milli-seconds to millennia and beyond. The solar activity, which has a ~11-year periodicity, is gradually declining in recent three solar cycles, suggesting a possibility of a grand minimum in near future. VarSITI—variability of the Sun and its terrestrial impact—was the 5-year program of the scientific committee on solar-terrestrial physics (SCOSTEP) in 2014–2018, focusing on this variability of the Sun and its consequences on the Earth. This paper reviews some background of SCOSTEP and its past programs, achievements of the 5-year VarSITI program, and remaining outstanding questions after VarSITI.

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)

scholarly journals Potential energy stored by planets and grand minima events

2011 ◽  
Vol 7 (S286) ◽  
pp. 410-413
Author(s):  
Rodolfo G. Cionco
Keyword(s):  
Solar Cycle ◽  
Solar System ◽  
Potential Energy ◽  
Internal Structure ◽  
Temporal Evolution ◽  
Maunder Minimum ◽  
The Sun ◽  
Dalton Minimum ◽  
Putative Mechanism ◽  
Grand Minima

AbstractRecently, Wolff & Patrone (2010), have developed a simple but very interesting model by which the movement of the Sun around the barycentre of the Solar system could create potential energy that could be released by flows pre-existing inside the Sun. The authors claim that it is the first mechanism showing how planetary movements can modify internal structure in the Sun that can be related to solar cycle. In this work we point out limitations of mentioned mechanism (which is based on interchange arguments), which could be inapplicable to a real star. Then, we calculate the temporal evolution of potential energy stored in zones of Sun's interior in which the potential energy could be most efficiently stored taking into account detailed barycentric Sun dynamics. We show strong variations of potential energy related to Maunder Minimum, Dalton Minimum and the maximum of Cycle 22, around 1990. We discuss briefly possible implications of this putative mechanism to solar cycle specially Grand Minima events.

scholarly journals Solar Activity and Svalbard Temperatures

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Jan-Erik Solheim ◽  
Kjell Stordahl ◽  
Ole Humlum
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Winter Temperature ◽  
Positive Trend ◽  
Seasonal Temperature ◽  
Solar Cycles ◽  
Temperature Variations ◽  
Mean Temperature ◽  
Cent Level ◽  
Cycle 24

The long temperature series at Svalbard (Longyearbyen) show large variations and a positive trend since its start in 1912. During this period solar activity has increased, as indicated by shorter solar cycles. The temperature at Svalbard is negatively correlated with the length of the solar cycle. The strongest negative correlation is found with lags 10–12 years. The relations between the length of a solar cycle and the mean temperature in the following cycle are used to model Svalbard annual mean temperature and seasonal temperature variations. Residuals from the annual and winter models show no autocorrelations on the 5 per cent level, which indicates that no additional parameters are needed to explain the temperature variations with 95 per cent significance. These models show that 60 per cent of the annual and winter temperature variations are explained by solar activity. For the spring, summer, and fall temperatures autocorrelations in the residuals exist, and additional variables may contribute to the variations. These models can be applied as forecasting models. We predict an annual mean temperature decrease for Svalbard of °C from solar cycle 23 to solar cycle 24 (2009–20) and a decrease in the winter temperature of °C.

scholarly journals Cosmic-ray propagation around the Sun: investigating the influence of the solar magnetic field on the cosmic-ray Sun shadow

2020 ◽  
Vol 633 ◽  
pp. A83
Author(s):  
J. Becker Tjus ◽  
P. Desiati ◽  
N. Döpper ◽  
H. Fichtner ◽  
J. Kleimann ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Solar Cycle ◽  
Cosmic Rays ◽  
Solar Magnetic Field ◽  
Cosmic Ray ◽  
High Energy ◽  
High Solar Activity ◽  
The Sun ◽  
Theoretical Understanding

The cosmic-ray Sun shadow, which is caused by high-energy charged cosmic rays being blocked and deflected by the Sun and its magnetic field, has been observed by various experiments, such as Argo-YBJ, Tibet, HAWC, and IceCube. Most notably, the shadow’s size and depth was recently shown to correlate with the 11-year solar cycle. The interpretation of such measurements, which help to bridge the gap between solar physics and high-energy particle astrophysics, requires a solid theoretical understanding of cosmic-ray propagation in the coronal magnetic field. It is the aim of this paper to establish theoretical predictions for the cosmic-ray Sun shadow in order to identify observables that can be used to study this link in more detail. To determine the cosmic-ray Sun shadow, we numerically compute trajectories of charged cosmic rays in the energy range of 5−316 TeV for five different mass numbers. We present and analyze the resulting shadow images for protons and iron, as well as for typically measured cosmic-ray compositions. We confirm the observationally established correlation between the magnitude of the shadowing effect and both the mean sunspot number and the polarity of the magnetic field during the solar cycle. We also show that during low solar activity, the Sun’s shadow behaves similarly to that of a dipole, for which we find a non-monotonous dependence on energy. In particular, the shadow can become significantly more pronounced than the geometrical disk expected for a totally unmagnetized Sun. For times of high solar activity, we instead predict the shadow to depend monotonously on energy and to be generally weaker than the geometrical shadow for all tested energies. These effects should become visible in energy-resolved measurements of the Sun shadow, and may in the future become an independent measure for the level of disorder in the solar magnetic field.

scholarly journals Photospheric activity of the Sun with VIRGO and GOLF

2017 ◽  
Vol 608 ◽  
pp. A87 ◽  
Author(s):  
D. Salabert ◽  
R. A. García ◽  
A. Jiménez ◽  
L. Bertello ◽  
E. Corsaro ◽  
...  
Keyword(s):  
Solar Activity ◽  
Radial Velocity ◽  
Wavelength Dependence ◽  
Solar Photosphere ◽  
The Sun ◽  
Solar Cycles ◽  
Quasi Biennial Oscillation ◽  
Photometric Observations ◽  
Cycle 24 ◽  
Biennial Oscillation

We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies were obtained by tracking the temporal modulations in the observations associated with the spots and magnetic features as the Sun rotates. We analyzed 21 yr of observations, spanning solar cycles 23 and 24, collected by the space-based photometric VIRGO and radial velocity GOLF instruments on board the SoHO satellite. We then calculated the photospheric activity proxy Sph is for each of the three VIRGO photometers and the associated Svel proxy from the radial velocity GOLF observations. Comparisons with several standard solar activity proxies sensitive to different layers of the Sun demonstrate that these new activity proxies, Sph and Svel, provide a new manner to monitor solar activity. We show that both the long- and short-term magnetic variabilities respectively associated with the 11-yr cycle and the quasi-biennial oscillation are well monitored, and that the magnetic field interaction between the subsurface, photosphere, and chromosphere of the Sun was modified between Cycle 24 and Cycle 23. Furthermore, the photometric proxies show a wavelength dependence of the response function of the solar photosphere among the three channels of the VIRGO photometers, providing inputs for the study of the stellar magnetism of Sun-like stars.

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