Changes of the Solar Meridional Velocity Profile During Cycle 23 Explained by Flows Toward the Activity Belts

Abstract

The solar meridional flow is an important ingredient in Babcock-Leighton type models of the solar dynamo. Global variations of this flow have been suggested to explain the variations in the amplitudes and lengths of the activity cycles. Recently, cycle-related variations in the amplitude of the P ¹ ₂ term in the Legendre decomposition of the observed meridional flow have been reported. The result is often interpreted in terms of an overall variation in the flow amplitude during the activity cycle. Using a semi-empirical model based upon the observed distribution of magnetic flux on the solar surface, we show that the reported variations of the P ¹ ₂ term can be explained by the observed localized inflows into the active region belts. No variation of the overall meridional flow amplitude is required.