Presentation #125.30 in the session General Topics: Solar — Poster Session.
Cyclical variations of the solar magnetic fields, and hence the level of solar activity, is among the top interests of space weather research and relates to climate change on Earth. Surface flows in global-scale, in particular differential rotation and meridional flows, play important roles in the solar dynamo that describes the origin and variation of solar magnetic fields. In principle, differential rotation is the fundamental cause of dipole field formation and emergence, and meridional flows are the surface component of a longitudinal circulation that brings decayed field from low latitudes to polar regions. Such flows are key inputs and constraints of observational and modeling studies of solar cycles. We have found a strong correlation of the surface flows from full-disk magnetograms using local correlation tracking (LCT) method and Halpha images using machine learning-based self-supervised optical flow (OF) method in Solar Cycle 23 and 24. Furthermore, we evaluated the uncertainties of using LCT and OF, respectively. In this work, we present the surface flow profiles, namely differential rotation, zonal flows, and meridional flows traced back in old solar cycles derived from Halpha images.