A Combined Analysis of the Observational Aspects of the Quasi-biennial Oscillation in Solar Magnetic Activity

Bazilevskaya, G. A.; Broomhall, Anne-Marie; Elsworth, Y.; Nakariakov, V. M.

doi:10.1007/978-1-4939-2584-1_12

Cited by 13 publications

(26 citation statements)

References 147 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The intrinsic timescales found in these IMFs seem to match once more those pertaining to the so-called quasi-biennial oscillations (QBOs) that have been observed in solar activities and proxies with periodicities between 0.6 and 4 years (Bazilevskaya et al, 2015;Kolotkov et al, 2015;Vecchio et al, 2012), as well as in meteorological data like Harrison (2008) who identifies a 1.68-year peak in cloud cover or high-latitude stratospheric temperatures and geopotential heights (Labitzke and Loon, 1988). Nevertheless, within the scope of the current analysis, the interpretation of these lowfrequency variability components as a real, possibly QBOlike, signal is uncertain.…”

Section: The Intrinsic Timescales Of Variability In the Ssisupporting

confidence: 53%

“…Its short-term timescales of variability, such as clouds briefly obscuring the Sun, are observed over seconds. At the opposite scale, thousands or even millions of years are to be used, as related to the change of the orbital parameters of the Earth-Sun system or to stellar evolution (Beer et al, 2006). In spite of this large span of characteristic scales of temporal variability, most of the studies dealing with this physical quantity have focused primarily on a few selected timescales of interest.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the intrinsic timescales of temporal variability in measurements of the surface solar radiation

Bengulescu

Blanc

Wald

2018

Nonlin. Processes Geophys.

View full text Add to dashboard Cite

Abstract. This study is concerned with the intrinsic temporal scales of the variability in the surface solar irradiance (SSI). The data consist of decennial time series of daily means of the SSI obtained from high-quality measurements of the broadband solar radiation impinging on a horizontal plane at ground level, issued from different Baseline Surface Radiation Network (BSRN) ground stations around the world. First, embedded oscillations sorted in terms of increasing timescales of the data are extracted by empirical mode decomposition (EMD). Next, Hilbert spectral analysis is applied to obtain an amplitude-modulation-frequencymodulation (AM-FM) representation of the data. The timevarying nature of the characteristic timescales of variability, along with the variations in the signal intensity, are thus revealed. A novel, adaptive null hypothesis based on the general statistical characteristics of noise is employed in order to discriminate between the different features of the data, those that have a deterministic origin and those being realizations of various stochastic processes. The data have a significant spectral peak corresponding to the yearly variability cycle and feature quasi-stochastic high-frequency variability components, irrespective of the geographical location or of the local climate. Moreover, the amplitude of this latter feature is shown to be modulated by variations in the yearly cycle, which is indicative of nonlinear multiplicative cross-scale couplings. The study has possible implications on the modeling and the forecast of the surface solar radiation, by clearly discriminating the deterministic from the quasistochastic character of the data, at different local timescales.

show abstract

Section: The Intrinsic Timescales Of Variability In the Ssisupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

On the intrinsic timescales of temporal variability in measurements of the surface solar radiation

Bengulescu

Blanc

Wald

2018

Nonlin. Processes Geophys.

View full text Add to dashboard Cite

show abstract

“…Fletcher et al (2010) found a quasi-biennial period of 2 years in the low-degree solar oscillation frequencies of the Sun after separating this signal from the influence of the dominant 11 year solar cycle. In addition, Bazilevskaya et al (2014) reported solar QBOs with the time scale of 0.6−4 years. In other stars, some short period variations were also reported.…”

Section: Introductionmentioning

confidence: 99%

Stellar Magnetic Cycles in the Solar-Like Stars Kepler-17 and Kepler-63

Estrela

Válio

2016

ApJ

View full text Add to dashboard Cite

The stellar magnetic field plays a crucial role in the star internal mechanisms, as in the interactions with its environment. The study of starspots provides information about the stellar magnetic field, and can characterise the cycle. Moreover, the analysis of solar-type stars is also useful to shed light onto the origin of the solar magnetic field. The objective of this work is to characterise the magnetic activity of stars. Here, we studied two solar-type stars Kepler-17 and Kepler-63 using two methods to estimate the magnetic cycle length. The first one characterises the spots (radius, intensity, and location) by fitting the small variations in the light curve of a star caused by the occultation of a spot during a planetary transit. This approach yields the number of spots present in the stellar surface and the flux deficit subtracted from the star by their presence during each transit. The second method estimates the activity from the excess in the residuals of the transit lightcurves. This excess is obtained by subtracting a spotless model transit from the lightcurve, and then integrating all the residuals during the transit. The presence of long term periodicity is estimated in both time series. With the first method, we obtained P cycle = 1.12 ± 0.16 yr (Kepler-17) and P cycle = 1.27 ± 0.16 yr (Kepler-63), and for the second approach the values are 1.35 ± 0.27 yr and 1.27 ± 0.12 yr, respectively. The results of both methods agree with each other and confirm their robustness.

show abstract

“…3 (a) one can easily see for SC 20-24 the double-peak structure of the sunspot maximum phase both in S ss and B hm f and corresponding double-gap signature in the GCR intensity (GG-effect). In [3] it was suggested that both step-like changes of the GCR intensity during the intermediate and low solar activity and the GG-effect around the sunspot maxima could be viewed as the manifestations of the quasi-biennial oscillations (QBO). However, note that the Gnevyshev gaps usually coincide or occur just after the inversions of the high-latitude SMF shown in Fig.…”

Section: The Gcr Intensity During Maximum Phase and Hmf Inversionmentioning

confidence: 99%

“…The maximum phase of the solar cycle is characterized by several interesting features in the solar activity, heliospheric parameters and the GCR intensity. First, the sunspot area and the heliospheric magnetic field (HMF) strength are at their highest levels during these periods and both often demonstrate the two-peak structure with the Gnevyshev Gap (GG) between the peaks (see [13,2,3] and references therein). In this paper by a maximum phase in the sunspot activity cycle we mean the period between two peaks of the two-peak structure in the Carrington rotation averaged sunspot area smoothed with 1 year period.…”

Section: Introductionmentioning

confidence: 99%

GCR intensity during the sunspot maximum phase and the inversion of the heliospheric magnetic field

Крайнев¹

2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

View full text Add to dashboard Cite

The maximum phase of the solar cycle is characterized by several interesting features in the solar activity, heliospheric characteristics and the galactic cosmic ray (GCR) intensity. Recently the maximum phase of the current solar cycle (SC) 24, in many relations anomalous when compared with solar cycles of the second half of the 20-th century, came to the end. The corresponding phase in the GCR intensity cycle is also in progress. In this paper we study different aspects of the sunspot, heliospheric and GCR behavior around this phase. First, the amplitudes of the SC 24 in the solar activity and GCR intensity are considered and compared with the previous sunspot cycles. Second, the inversion of the heliospheric magnetic field is studied for SC 21-24 using the suggested classification of its polarity distributions. Third, the GCR-effects specific for the maximum phase of SC 21-24 are considered and correlated with the behavior of the heliospheric magnetic field's strength and with the inversion of its polarity. Our main conclusions are as follows:1. The maximum phase of the sunspot SC 24 ended in 06.2014, the development of the sunspot cycle being similar to those of SC 14, 15 (the Glaisberg minimum). The maximum phase of SC 24 in the GCR intensity is still in progress.2. The inversion of the heliospheric magnetic field consists of three stages, characterized by the appearance of the global heliospheric current sheet (HCS), connecting all longitudes. In two "transition dipole" stages beside the global HCS there are additional local HCSs, while the "inversion" stage lies between two "transition dipole" ones and there is no global HCS in this stage. The "inversion" stage of the current SC 24 is the longest when compared with those for SC 21-23. The second "transition dipole" stage and hence the whole inversion period of the heliospheric magnetic field in SC 24 provisionally ended in 08.2014.3. The behavior of the GCR intensity in the period of the sunspot maximum phase and the inversion of the heliospheric magnetic fields for SC 21-23 demonstrates all the characteristic features for this period: the two-gap structure corresponding to two-peak structure in the sunspot activity, and the energy hysteresis. In the current SC 24 the GCR intensity shows rather unusual features and we should wait for one or even two years to see the whole picture.

show abstract

A Combined Analysis of the Observational Aspects of the Quasi-biennial Oscillation in Solar Magnetic Activity

Cited by 13 publications

References 147 publications

On the intrinsic timescales of temporal variability in measurements of the surface solar radiation

On the intrinsic timescales of temporal variability in measurements of the surface solar radiation

Stellar Magnetic Cycles in the Solar-Like Stars Kepler-17 and Kepler-63

GCR intensity during the sunspot maximum phase and the inversion of the heliospheric magnetic field

Contact Info

Product

Resources

About