Information-theory-based System-level Babcock–Leighton Flux Transport Model–Data Comparisons

System-level Babcock–Leighton flux transport model–data comparisons are performed using information theory. The model is run with a maximum meridional flow speed of 16.5 m s −1 with the flow speed systematically varied by 20% (BLFT20) and 50% (BLFT50). Overall, the comparisons show that the models qualitatively capture much of the information flow among the toroidal field (sunspot number), polar field, and meridional flow. BLFT20 generally compares better than BLFT50, suggesting that meridional flow variation of 20% may be more realistic than 50%. However, the information flow from the meridional flow to the polar field is captured better in BLFT50. There is more information flow from the sunspot number to the polar field than the other way around in BLFT20 and observations. The information flow from the polar field to the sunspot number peaks at lag times ( τ ) of ∼2 yr and 7–9 yr in observations and BLFT20. The results can shed light on the nature of the Sun’s magnetic memory, the diffusive/dissipative processes, and advection in the turbulent flux transport at the Sun.