Impact of Time-varying High-latitude Meridional Circulation Cell in Polar Fields

Solar differential rotation, undergoing (magneto)hydrodynamics in the presence of magnetic fields, can produce cyclones and anticyclones, i.e. anticlockwise and clockwise flows, respectively associated with high and low pressure regions. These swirls at high-latitudes may or may not be very tightly confined to the poles, or exactly circumpolar either. Instead they can be obliquely rotating about the polar axis. Nonetheless, these nonaxisymmetric swirling plasma near the poles will appear as time-varying modulations in the mean meridional circulation. By incorporating several plausible time-varying reverse, high-latitude flow cells extending from pole down to about 60-degree latitudes, we perform a number of numerical experiments to simulate polar fields in a flux-transport dynamo model and estimate the short-term variability in polar faculae evolutionary patterns. Our simulations indicate that a much faster appearance and disappearance of a strong reverse flow cell approximately with a time-scale of about two weeks can successfully reproduce the short time-scale (~monthly ?) criss-cross type evolutions of polar faculae. Speed, profile and time-variation of meridional flow poleward of 60-degrees latitude are not known from observations yet. Long-awaited SOLARIS mission's data for polar regions' flow can validate (or unvalidate) our model-results.