Authors: Mausumi Dikpati, Peter A. Gilman, Giuliana de Toma; Thierry Corbard;
Edward J. Rhodes; Deborah A. Haber; Richard S. Bogart; Perry J. Rose
Affiliation: National Center for Atmospheric Research, High Altitude Observatory;
Observatorie de la Cote d'Azur; University of Southern California; JILA, University
of Colorado; Stanford University; University of Southern California
Given the success of a recently built flux-transport dynamo-based scheme (ApJ,
2004, 601, 1136) in reproducing observed polar field features in cycle 23 including
a) why the polar reversal was unusually slow, b) why the polar field build-up
was slow after the reversal and c) why the N-pole reversed a year before the
S-pole, we apply this scheme to predict some features of solar cycle 24. It
has already been shown (ApJ 2000, 543, 1027) that the duration of the Sun's
memory of its own magnetic field is primarily governed by the meridional flow
speed in flux-transport dynamos, and is no less than two solar cycles. Therefore,
observations of the Sun's magnetic field patterns at least over the past two
cycles, and dynamical changes in the Sun's large-scale mass-flow in which the
solar magnetic fields are partially frozen, should play important roles in determining
certain features in the upcoming solar cycle. We first theoretically demonstrate
how the surface magnetic fields would differ when the dynamo-generated magnetic
fields evolve in differing meridional flows, including acceleration, deceleration,
and N-S asymmetry in the flow-pattern. We then discuss using the MWO helioseismic
archive for extracting the observed changes in meridional flow over the past
20 years. By incorporating this long-term dynamical variation in flow-pattern
in our prediction model, if we can tune the model to successfully reproduce
various "anomalies" in solar cycle 23, we can attempt an early prediction
for solar cycle 24.
We acknowledge support from NASA through awards W-10107 and W-10175. National
Center for Atmospheric Research is sponsored by National Science Foundation.