Can Surface Flux Transport Account for the Weak Polar Field in Cycle 23?

Jiang, Jingyang; Cameron, R. H.; Schmitt, D.; Schüßler, M.

doi:10.1007/s11214-011-9783-y

Cited by 30 publications

(27 citation statements)

References 33 publications

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“…Please note that different definitions of the polar field were used between the observation (left panel, line-of-sight component and averaged over 35 • wide polar caps) and the reconstruction (right panel, radial component and averaged over the 15 • wide polar caps). Jiang et al (2011c) show that they are consistent when the same definitions are used. The good correlation provides the evidence for the polar field to be the solar cycle precursor.…”

Section: Solar Polar Field Precursorsupporting

confidence: 55%

Solar-cycle precursors and predictions

Jiang

2012

Proc. IAU

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Abstract. The sunspot number data during the past 400 years indicates that both the profile and the amplitude of the solar cycle have large variations. Some precursors of the solar cycle were identified aiming to predict the solar cycle. The polar field and the geomagnetic index are two precursors which are received the most attention. The geomagnetic variations during the solar minima are potentially caused by the solar polar field by the connection of the solar open flux. The robust prediction skill of the polar field indicates that the memory of the dynamo process is less than 11 yrs based on the frame of the Babcock-Leighton flux transport dynamo. One possible reason to get the short magnetic memory is the high magnetic diffusivity in the convective zone. Our recent studies show that the radial downward pumping is another possible reason. Based upon the mechanism, we well simulate the cycle irregularities during RGO time period. This opens the possibility to set up a standard dynamo based model to predict the solar cycle. In the end, the no correlation between the polar field and the preceding cycle strength due to two nonlinearities involved in the sunspot emergence will be stressed.

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Section: Solar Polar Field Precursorsupporting

confidence: 55%

Solar-cycle precursors and predictions

Jiang

2012

Proc. IAU

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“…The converging motion of the meridional flow in the activity band or the active region inflow (e.g., Haber et al 2002;Zhao & Kosovichev 2004;Hathaway & Rightmire 2010) in the low latitude will prevent the cross-equatorial transport of the magnetic flux (e.g., De Rosa & Schrijver 2006;Cameron & Schüssler 2012;Martin-Belda & Cameron 2017). The high gradient of the meridional flow near the equator is also a possible origin of the small cross-equatorial flux transport (Schrijver & Liu 2008;Jiang et al 2013). Although the meridional flow variation at the Cycle 23/24 minimum is not suitable to explain the observed axial dipole moment (Upton & Hathaway 2014a), the effect on the flux transport should be considered to explain the plateau.…”

Section: Discussionmentioning

confidence: 99%

Improvement of solar-cycle prediction: Plateau of solar axial dipole moment

Iijima

Hotta

Imada

et al. 2017

A&A

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Aims. We report the small temporal variation of the axial dipole moment near the solar minimum and its application to the solar-cycle prediction by the surface flux transport (SFT) model. Methods. We measure the axial dipole moment using the photospheric synoptic magnetogram observed by the Wilcox Solar Observatory (WSO), the ESA/NASA Solar and Heliospheric Observatory Michelson Doppler Imager (MDI), and the NASA Solar Dynamics Observatory Helioseismic and Magnetic Imager (HMI). We also use the SFT model for the interpretation and prediction of the observed axial dipole moment. Results. We find that the observed axial dipole moment becomes approximately constant during the period of several years before each cycle minimum, which we call the axial dipole moment plateau. The cross-equatorial magnetic flux transport is found to be small during the period, although a significant number of sunspots are still emerging. The results indicate that the newly emerged magnetic flux does not contribute to the build up of the axial dipole moment near the end of each cycle. This is confirmed by showing that the time variation of the observed axial dipole moment agrees well with that predicted by the SFT model without introducing new emergence of magnetic flux. These results allow us to predict the axial dipole moment at the Cycle 24/25 minimum using the SFT model without introducing new flux emergence. The predicted axial dipole moment at the Cycle 24/25 minimum is 60-80 percent of Cycle 23/24 minimum, which suggests the amplitude of Cycle 25 is even weaker than the current Cycle 24. Conclusions. The plateau of the solar axial dipole moment is an important feature for the longer-term prediction of the solar cycle based on the SFT model.

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“…We use the MUDPACK package here to solve Equation (3) in its nonseparable form in spherical coordinates, subject to the boundary conditions described above. Jiang & Feng (2012) have recently presented a high-speed combined spectral/finite-difference PFSS solution method using the related NCAR FISHPACK package.…”

Section: Finite-difference Potential-field Source-surface Models For mentioning

confidence: 99%

“…One explanation is that the meridional flows are so fast that the leading polarities in the two hemispheres do not have time to interconnect and interact with each other before being swept poleward (e.g., Schrijver & Liu 2008;Wang et al 2009;Nandy et al 2011). To affect the polar fields significantly, these fast meridional flows would have to occur at active latitudes, as Dikpati (2011) An alternative explanation is that the active region Joy's law tilts lost their hemispheric bias during cycle 23 (e.g., Jiang et al 2011;Petrie 2012). In this scenario approximately equal quantities of each polarity would be sent poleward with approximately zero net effect on the polar fields even for slow meridional flow speeds.…”

Section: Multipolar Fieldsmentioning

confidence: 99%

Solar Magnetic Activity Cycles, Coronal Potential Field Models and Eruption Rates

Petrie

2013

ApJ

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We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the National Solar Observatory's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun vector spectro-magnetograph, the spectro-magnetograph and the 512-channel magnetograph instruments, and from Stanford University's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Polar field changes are found to be well correlated with active fields over most of the period studied, except between 2003 and 2006 when the active fields did not produce significant polar field changes. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The tilt of the solar dipole is therefore almost entirely due to active-region fields. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking, Solar Eruptive Event Detection System, and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003 and 2012 than for those between 1997 and 2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

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Can Surface Flux Transport Account for the Weak Polar Field in Cycle 23?

Cited by 30 publications

References 33 publications

Solar-cycle precursors and predictions

Solar-cycle precursors and predictions

Improvement of solar-cycle prediction: Plateau of solar axial dipole moment

Solar Magnetic Activity Cycles, Coronal Potential Field Models and Eruption Rates

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