The faster meridional flow that preceded the solar cycle 23/24 minimum is thought to have led to weaker polar field strengths , producing the extended solar minimum and the unusually weak cycle 24 .
To determine the impact of meridional flow variations on the sunspot cycle , we have simulated the Sun ’ s surface magnetic field evolution with our newly developed surface flux transport model .
We investigate three different cases : a constant average meridional flow , the observed time-varying meridional flow , and a time-varying meridional flow in which the observed variations from the average have been doubled .
Comparison of these simulations shows that the variations in the meridional flow over cycle 23 have a significant impact ( \sim 20 % ) on the polar fields .
However , the variations produced polar fields that were stronger than they would have been otherwise .
We propose that the primary cause of the extended cycle 23/24 minimum and weak cycle 24 was the weakness of cycle 23 itself - with fewer sunspots , there was insufficient flux to build a big cycle .
We also find that any polar counter-cells in the meridional flow ( equatorward flow at high latitudes ) produce flux concentrations at mid-to-high latitudes that are not consistent with observations .