Speaker
Description
To improve solar 11 yr cycle forecast one must be able to take into account the rising/declining phase asymmetry of the cycle. In our Solar Predict 11 yr cycle forecasting tool based on a 4D-var assimilation technique coupled to a Babcock-Leighton mean field dynamo model - we use meridional circulation as the primary control parameter for determining the future cycle's length and amplitude. In order to assess how the meridional flow could be further used to take into account the cycle asymmetry in the 11yr cycle prediction, we have performed a suite of kinematic dynamo simulations incorporating several physically motivated and time-dependent meridional flow profiles. To quantify the asymmetry, we examine four diagnostic parameters: (1) the relationship between rise and decay times, (2) the correlation between cycle amplitude and rise time, (3) the correlation between cycle amplitude and rise rate, and (4) the correlation between cycle amplitude and the decay rate near the preceding minimum. We find that the rise–decay time asymmetry is highly sensitive to the temporal structure of the meridional flow. In all scenarios, a statistically significant positive correlation emerges between the cycle amplitude and rise rate, reaffirming this as a robust and consistent proxy for cycle strength. In contrast, correlations between the cycle amplitude and both the rise time and the decay rate near the preceding minimum are generally weak or statistically insignificant, particularly in cases involving nonlinear or feedback-modulated flows. These findings underscore the critical role of meridional circulation variability in shaping solar cycle asymmetry and emphasize the need for improved observational constraints on its spatiotemporal behavior.
| Do you plan to attend in-person or online? | In-person |
|---|
