Effect of Morphological Asymmetry between Leading and Following Sunspots on the Prediction of Solar Cycle Activity

Iijima, Haruhisa; Hotta, Hideyuki; Imada, Shinsuke

doi:10.3847/1538-4357/ab3b04

Cited by 18 publications

(20 citation statements)

References 57 publications

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“…As discussed above in the Introduction, data for individual active regions are often missing for the smaller ARs, while in the case of the larger, more complex AR representing them by an instantaneously introduced bipole is nontrivial. As it was recently pointed out by Iijima et al (2019), for an AR with zero tilt but different extents of the two polarity distributions dD 1 will be nonzero, even though dD 1 = 0 for this configuration. The reason is that the configuration has a nonzero quadrupole moment, which may alternatively be represented by not one but two oppositely oriented dipoles slightly shifted in latitude.…”

Section: Introducing Ardormentioning

confidence: 59%

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Towards an algebraic method of solar cycle prediction

Nagy

Petrovay

Lemerle

et al. 2020

J. Space Weather Space Clim.

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An algebraic method for the reconstruction and potentially prediction of the solar dipole moment value at sunspot minimum (known to be a good predictor of the amplitude of the next solar cycle) was suggested in the first paper in this series. The method sums up the ultimate dipole moment contributions of individual active regions in a solar cycle: for this, detailed and reliable input data would in principle be needed for thousands of active regions in a solar cycle. To reduce the need for detailed input data, here we propose a new active region descriptor called ARDoR (Active Region Degree of Rogueness). In a detailed statistical analysis of a large number of activity cycles simulated with the 2x2D dynamo model we demonstrate that ranking active regions by decreasing ARDoR, for a good reproduction of the solar dipole moment at the end of the cycle it is sufficient to consider the top N regions on this list explicitly, where N is a relatively low number, while for the other regions the ARDoR value may be set to zero. E.g., with N =5 the fraction of cycles where the dipole moment is reproduced with an error exceeding ±30% is only 12%, significantly reduced with respect to the case N =0, i.e. ARDoRs set to zero for all active regions, where this fraction is 26%. This indicates that stochastic effects on the intercycle variations of solar activity are dominated by the effect of a low number of large "rogue" active regions, rather than the combined effect of numerous small ARs. The method has a potential for future use in solar cycle prediction.

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Section: Introducing Ardormentioning

confidence: 59%

“…The complexities of AR structure imply that their representation with a single bipole may be subject to doubt (cf. Iijima et al, 2019;Jiang et al, 2019). And for historical data these difficulties are further aggravated.…”

Section: Discussionmentioning

confidence: 99%

Towards an algebraic method of solar cycle prediction

Nagy

Petrovay

Lemerle

et al. 2020

J. Space Weather Space Clim.

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“…Note that while in the dynamo model used here for comparison ARs were assumed to be be bipolar, in applications to solar data a further source of uncertainty concerns to what extent a bipolar representation reflects the structure of ARs (cf. Iijima et al, 2019;Jiang et al, 2019;Yeates, 2020).…”

Section: Discussionmentioning

confidence: 99%

Towards an algebraic method of solar cycle prediction

Petrovay

Nagy

Yeates

2020

J. Space Weather Space Clim.

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We discuss the potential use of an algebraic method to compute the value of the solar axial dipole moment at solar minimum, widely considered to be the most reliable precursor of the activity level in the next solar cycle. The method consists of summing up the ultimate contributions of individual active regions to the solar axial dipole moment at the end of the cycle. A potential limitation of the approach is its dependence on the underlying surface flux transport (SFT) model details. We demonstrate by both analytical and numerical methods that the factor relating the initial and ultimate dipole moment contributions of an active region displays a Gaussian dependence on latitude with parameters that only depend on details of the SFT model through the parameter η/ D u where η is supergranular diffusivity and D u is the divergence of the meridional flow on the equator. In a comparison with cycles simulated in the 2x2D dynamo model we further demonstrate that the inaccuracies associated with the algebraic method are minor and the method may be able to reproduce the dipole moment values in a large majority of cycles.

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“…Similar asymmetries exist in the Sun's polar magnetic fields (e.g. Nistico et al 2015;Bhowmik 2019) and even sunspot numbers (Wang & Robbrecht 2011;Iijima et al 2019), but the origin of the asymmetry of the HCS is not yet understood. The north-south asymmetry in solar activity must be driven by the solar dynamo and the interaction of the sub-surface magnetic field with the flows present there.…”

Section: What Drives the Solar Wind And Where Does The Coronal Magnetmentioning

confidence: 97%

The Solar Orbiter mission

Müller

Cyr

Zouganelis

et al. 2020

A&A

731

281

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Aims. Solar Orbiter, the first mission of ESA’s Cosmic Vision 2015–2025 programme and a mission of international collaboration between ESA and NASA, will explore the Sun and heliosphere from close up and out of the ecliptic plane. It was launched on 10 February 2020 04:03 UTC from Cape Canaveral and aims to address key questions of solar and heliospheric physics pertaining to how the Sun creates and controls the Heliosphere, and why solar activity changes with time. To answer these, the mission carries six remote-sensing instruments to observe the Sun and the solar corona, and four in-situ instruments to measure the solar wind, energetic particles, and electromagnetic fields. In this paper, we describe the science objectives of the mission, and how these will be addressed by the joint observations of the instruments onboard. Methods. The paper first summarises the mission-level science objectives, followed by an overview of the spacecraft and payload. We report the observables and performance figures of each instrument, as well as the trajectory design. This is followed by a summary of the science operations concept. The paper concludes with a more detailed description of the science objectives. Results. Solar Orbiter will combine in-situ measurements in the heliosphere with high-resolution remote-sensing observations of the Sun to address fundamental questions of solar and heliospheric physics. The performance of the Solar Orbiter payload meets the requirements derived from the mission’s science objectives. Its science return will be augmented further by coordinated observations with other space missions and ground-based observatories.

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Effect of Morphological Asymmetry between Leading and Following Sunspots on the Prediction of Solar Cycle Activity

Cited by 18 publications

References 57 publications

Towards an algebraic method of solar cycle prediction

Towards an algebraic method of solar cycle prediction

Towards an algebraic method of solar cycle prediction

The Solar Orbiter mission

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