Solar Cycle Prediction Using Precursors and Flux Transport Models

By R. Cameron, M. Schüssler. 2006

141 citations recorded by the source corpus.

We study the origin of the predictive skill of some methods to forecast the strength of solar activity cycles. A simple flux transport model for the azimuthally averaged radial magnetic field at the solar surface is used, which contains a source term describing the emergence of new flux based on observational sunspot data. We consider the magnetic flux diffusing over the equator as a predictor, since this quantity is directly related to the global dipole field from which a Babcock-Leighton dynamo generates the toroidal field for the next activity cycle. If the source is represented schematically by a narrow activity belt drifting with constant speed over a fixed range of latitudes between activity minima, our predictor shows considerable predictive skill, with correlation coefficients up to 0.95 for past cycles. However, the predictive skill is completely lost when the actually observed emergence latitudes are used. This result originates from the fact that the precursor amplitude is determined by the sunspot activity a few years before solar minimum. Since stronger cycles tend to rise faster to their maximum activity (known as the Waldmeier effect), the temporal overlapping of cycles leads to a shift of the minimum epochs that depends on the strength of the following cycle. This information is picked up by precursor methods and also by our flux transport model with a schematic source. Therefore, their predictive skill does not require a memory, i.e., a physical connection between the surface manifestations of subsequent activity cycles.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b554f1e469372917d5548b06df8fbaf8c799e2c5

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In Astronomy and Astrophysics

Citations in the corpus

The Solar Cycle (2007, methodology): “Cameron and Schüssler (2007) suggest that it is simply the overlap of the sunspot cycles and the Waldmeier Effect that leads to these precursor relationships with the next cycle’s amplitude.”
ON THE WEAKENING OF THE POLAR MAGNETIC FIELDS DURING SOLAR CYCLE 23 (2009, methodology): “…prediction methods in which the sunspots of the next cycle are generated by converting the pre-existing poloidal field into toroidal flux (Cameron & Schüssler 2007; Choudhuri et al. 2007; Dikpati 2008; Dikpati & Gilman 2006; Dikpati et al. 2006, 2008; Hathaway 2009; Schatten 2005;…”
Solar Dynamo Theory (2014, background): “Interestingly, these two closely related dynamo-based approaches have led to markedly distinct predictions for cycle 24, indicating that the prediction is sensitive to modeling details (see also Cameron & Schüssler 2007, Bushby & Tobias 2007).”
Solar activity forecast with a dynamo model (2007, methodology): “Using suitably averaged sunspot area data, Cameron & Schüssler (2007) found a rather intriguing correlation between the theoretically computed magnetic flux crossing the equator at the minimum and the strength of the next maximum, for the last few cycles.”
The Solar Cycle (2010, background): “Cameron and Schüssler (2007) suggest that it is simply the overlap of the sunspot cycles and the Waldmeier Effect that leads to these precursor relationships with the next cycle’s amplitude.”
Exploring the Physical Basis of Solar Cycle Predictions: Flux Transport Dynamics and Persistence of Memory in Advection- versus Diffusion-dominated Solar Convection Zones (2007, background): “In a recent analysis, Cameron & Schüssler (2007) find that the predictive skill of a surface flux transport model – similar in spirit to the advection-dominated dynamo model of Dikpati et al. (2006) – is contained in the input information of sunspot areas in the declining phase of the cycle.”
Magnetic Flux Transport at the Solar Surface (2014, background): “For plausible values of the meridional flow speed 14 and magnetic diffusivity, the e-folding time of the slowest decaying solution s about 4000 years (Cameron and Schüssler 2007).”