Do polar faculae on the sun predict a sunspot cycle?

Макаров, В. И.; Makarova, V. V.; Sivaraman, K. R.

doi:10.1007/bf00146211

Cited by 35 publications

(16 citation statements)

References 7 publications

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“…In this context it is interesting to note that Makarov et al (1989) and Makarov and Makarova (1996) found that the number of polar faculae observed at Kislovodsk anticipates the next sunspot cycle with a time lag of 5-6 years on average in cycles 20-22; even short term annual variations or ''surges'' of sunspot activity were claimed to be discernible in the polar facular record. An apparently conflicting result was obtained by Li et al (2002), who found using the Mitaka data base that the best autocorrelation results with a time shift of about 4 years only.…”

Section: Extending the Range Of The Polar Precursor: Early Forecasts mentioning

confidence: 99%

Solar cycle prediction

Petrovay

2020

Living Rev Sol Phys

195

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A review of solar cycle prediction methods and their performance is given, including early forecasts for Cycle 25. The review focuses on those aspects of the solar cycle prediction problem that have a bearing on dynamo theory. The scope of the review is further restricted to the issue of predicting the amplitude (and optionally the epoch) of an upcoming solar maximum no later than right after the start of the given cycle. Prediction methods form three main groups. Precursor methods rely on the value of some measure of solar activity or magnetism at a specified time to predict the amplitude of the following solar maximum. The choice of a good precursor often implies considerable physical insight: indeed, it has become increasingly clear that the transition from purely empirical precursors to model-based methods is continuous. Model-based approaches can be further divided into two groups: predictions based on surface flux transport models and on consistent dynamo models. The implicit assumption of precursor methods is that each numbered solar cycle is a consistent unit in itself, while solar activity seems to consist of a series of much less tightly intercorrelated individual cycles. Extrapolation methods, in contrast, are based on the premise that the physical process giving rise to the sunspot number record is statistically homogeneous, i.e., the mathematical regularities underlying its variations are the same at any point of time, and therefore it lends itself to analysis and forecasting by time series methods. In their overall performance during the course of the last few solar cycles, precursor methods have clearly been superior to extrapolation methods. One method that has This article is a revised version of

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Section: Extending the Range Of The Polar Precursor: Early Forecasts mentioning

confidence: 99%

Solar cycle prediction

Petrovay

2020

Living Rev Sol Phys

195

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“…In other words, PNI constructed by us is in good agreement with the MWO faculae counts, but not with the NOAJ faculae counts. Furthermore, Makarov et al (1989) manually counted the polar bright points above 50 0 in both the hemispheres for the period 1940-1957 (with a data gap between 1947-1948) from KKL Ca-K spectroheliograms. They found an anti-correlation between polar bright points and sunspot number for the two cycles and suggested that Ca-K polar bright points can be used as a proxy to predict the characteristics of the next solar cycle.…”

Section: Validation Of Kkl Pni Indexmentioning

confidence: 99%

Polar Network Index as a Magnetic Proxy for the Solar Cycle Studies

Priyal

Banerjee

Karak

et al. 2014

ApJ

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The Sun has a polar magnetic field which oscillates with the 11-year sunspot cycle. This polar magnetic field is an important component of the dynamo process which is operating in the solar convection zone and produces the sunspot cycle. We have systematic direct measurements of the Sun's polar magnetic field only from about mid-1970s. There are, however, indirect proxies which give us information about this field at earlier times. The Ca-K spectroheliograms taken in Kodaikanal Solar Observatory during 1904 -2007 have now been digitized with the 4k × 4k CCD and have higher resolution (∼ 0.86 arcsec) than the other available historical datasets. From these Ca-K spectroheliograms, we have developed a completely new proxy (Polar Network Index: PNI) for the Sun's polar magnetic field. We calculate the PNI from the digitized images using an automated algorithm and calibrate our measured PNI against the polar field as measured by the Wilcox Solar Observatory for the period of 1976-1990. This calibration allows us to estimate polar fields for the earlier period up to 1904.The dynamo calculations done with this proxy as input data reproduce the Sun's magnetic behavior for the past century reasonably well.

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“…The magnetic field reversals at the northern and southern poles of the Sun are the phenomenon in the polar zones that imparts the cyclic nature on the solar activity [ Makarov et al , 2005]. With the use of H α synoptic charts, Makarov and Sivaraman [1989], Makarov et al [2005], and Makarov et al [2001] worked out the epochs of polar field reversal over a period of 12 solar cycles from 1872 to 2001, showing that after polar field reversal, the new appearing magnetic polarity on a hemisphere will become the leading magnetic polarity of regions at low latitudes on the same hemisphere in the following normal cycle. During the course of a sunspot cycle, namely a normal low‐latitude cycle, the trailing polarity field first cancels the field of opposite polarity left over from the previous sunspot cycle.…”

Section: Solar Full‐disk Activity Cyclementioning

confidence: 99%

“…The velocity of the poleward migration of solar activity is in range of several to tens meters per second. It is 10 to 25 m s −1 for filament activity [ Minarovjech et al , 1998b] or 4 to 29 m s −1 [ Makarov and Sivaraman , 1989], several meters per second for the green‐corona intensities [ Minarovjech et al , 2007], 7 to 20 m s −1 for the surface magnetic fields.…”

Section: Fine‐scale Characteristics Of Full‐disk Activity Cyclesmentioning

confidence: 99%

Cyclic behavior of solar full‐disk activity

Gao

et al. 2008

J. Geophys. Res.

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In order to describe the cyclic behavior of solar full‐disk activity (the surface magnetic fields, filaments, the green Fe XIV, 5303Å corona local maxima intensities, and torsional oscillations), we propose a new concept, a “full‐disk activity cycle,” which consists of two successive normal cycles: a high‐latitude activity cycle following a low‐latitude activity cycle. When solar activity begins to progress into a full‐disk activity cycle, it latitudinally rushes to the poles, starting from middle latitudes (about 40°) at about a normal cycle minimum. At the solar poles, magnetic polarity reversal takes place on both the solar hemispheres, and opposite reversals occur on the opposite hemispheres; resultingly, the new appearing magnetic polarity at high latitudes on a hemisphere will become the leading magnetic polarity of regions at low latitudes on the same hemisphere in the following normal cycle. After the latitudinal drift of solar activity reaches the solar poles at about the maximum time of the normal cycle, solar activity begins to latitudinally migrate in a reverse direction; it moves toward the equator continually till almost arriving at the solar equator and lasting for about 1.5 normal cycles. When a full‐disk activity cycle progresses from a high‐latitude activity cycle into a low‐latitude activity cycle, the next full‐disk activity cycle begins. Two successive full‐disk activity cycles have a normal cycle overlapped in time but are spatially separated. The characteristics of full‐disk activity cycles are summarized as well. At present we do not know why a full‐disk activity cycle begins at midlatitudes; it is perhaps related with solar differential rotation. Further work is required to uncover the physical mechanisms behind the concept.

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Do polar faculae on the sun predict a sunspot cycle?

Cited by 35 publications

References 7 publications

Solar cycle prediction

Solar cycle prediction

Polar Network Index as a Magnetic Proxy for the Solar Cycle Studies

Cyclic behavior of solar full‐disk activity

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