Comparison of SWAMIS and MagTrak Measurements of Solar Surface Axisymmetric Flows

We compare solar surface axisymmetric flows (differential rotation and meridional circulation) as traced by faculae at low latitudes with contemporaneous measurements of features seen in photospheric magnetograms. We employ the same feature tracking code, SWAMIS, to measure both, differing only in the details of data preparation and tracking parameters, in order to minimize the systematic differences that would arise from using different algorithms. We then compare these results to the flows obtained by the MagTrak code, which correlates across time steps long strips of magnetograms that have been projected into heliographic coordinates. We present results for a few solar rotations, as a prelude to comparisons across longer time spans.