The predictability of advection-dominated flux-transport solar dynamo models

TL;DR

This study quantifies the predictability window of an advection-dominated flux-transport solar dynamo model by analyzing its sensitivity to initial conditions and parameters, estimating a predictability horizon of about 2.76 solar cycles.

Contribution

It provides a quantitative estimate of the predictability horizon for flux-transport solar dynamo models based on perturbation analysis and sensitivity to key parameters.

Findings

The e-folding time decreases with stronger α-effect.

The e-folding time increases with larger meridional circulation.

Estimated predictability horizon is approximately 2.76 solar cycles.

Abstract

Space weather is a matter of practical importance in our modern society. Predictions of forecoming solar cycles mean amplitude and duration are currently being made based on flux-transport numerical models of the solar dynamo. Interested in the forecast horizon of such studies, we quantify the predictability window of a representative, advection-dominated, flux-transport dynamo model by investigating its sensitivity to initial conditions and control parameters through a perturbation analysis. We measure the rate associated with the exponential growth of an initial perturbation of the model trajectory, which yields a characteristic time scale known as the e-folding time $\tau_e$. The e-folding time is shown to decrease with the strength of the $\alpha$-effect, and to increase with the magnitude of the imposed meridional circulation. Comparing the e-folding time with the solar cycle periodicity, we obtain an average estimate for $\tau_e$ equal to 2.76 solar cycle durations. From a practical point of view, the perturbations analysed in this work can be interpreted as uncertainties affecting either the observations or the physical model itself. After reviewing these, we discuss their implications for solar cycle prediction.