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Paper: |
Solar-Cycle Variation of Subsurface Zonal Flow Derived from Ring-Diagram Analysis |
Volume: |
478, Fifty Years of Seismology of the Sun and Stars |
Page: |
217 |
Authors: |
Komm, R.; Howe, R.; González Hernández, I.; Hill, F.; Bogart, R. S.; Haber, D. |
Abstract: |
We study the solar-cycle variation of the zonal flow in the near-surface layers
of the solar convection zone from the surface to a depth of 16 Mm. We have analyzed
Global Oscillation Network Group (GONG) and Helioseismic and Magnetic Imager
(HMI) Dopplergrams with the ring-diagram analysis covering about 12 years combined.
The zonal flow varies with the solar cycle showing faster-than-average flows
equatorward of the mean latitude of activity and slower-than-average flows on the
poleward side. The bands of fast zonal flow appear at mid-latitudes about two years
before magnetic activity of cycle 24 is seen. The poleward branch of this variation
is visible as bands of fast zonal flow near 50° latitude in both HMI and GONG data. |
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