Variations in the Suns Axisymmetric Flows During Solar Cycles 23 and 24
Abstract
The axisymmetric flows, differential rotation and meridional circulation, are essential components of the solar dynamo. We have measured these flows in the surface shear layer for each Carrington Rotation during solar cycles 23 and 24 (1996-2021) by tracking the motions of the magnetic network seen in magnetograms from SOHO/MDI and SDO/HMI. We describe several improvements that have been made to our pattern tracking algorithm, including the removal of a systematic shift away from the disc center. Weak variations in the differential rotation, known as the torsional oscillation, feature slower flows on the poleward sides of the active latitudes and a high latitude spin-up at cycle maxima. These variations were smaller during the weaker cycle 24. Variations in the meridional flow include a slowing of the flow in the active latitudes during cycle maxima, which was more pronounced in Cycle 23 than in the weaker Cycle 24. Furthermore, we find evidence of transient counter-cells at high latitudes which appear seems unrelated to the solar activity cycle.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMSH54A..01U