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| Paper: |
Measuring Meridional Circulation in the Sun |
| Volume: |
416, Solar-Stellar Dynamos as Revealed by Helio- and Asteroseismology: GONG 2008/SOHO 21 |
| Page: |
103 |
| Authors: |
Duvall, T. L. Jr.; Hanasoge, S. M. |
| Abstract: |
Measuring the depth variation of the meridional flows is important
for understanding the solar cycle, at least according to a number
of dynamo models. While attempting to extend the early observations
of Giles (2000) of time-distance measurements of flow, we have
stumbled upon some systematic errors that can affect these
measurements: 1) the additional distance traveled by radiation
coming from points away from disk center causes an apparent
‘shrinking’ Sun, that is an apparent flow towards the disk center
and 2) in measurements away from the central longitude, the rotation
signal can leak into meridional flow signals. Attempts to understand
and overcome these systematic problems will be presented. Forward
models based on ray theory have been applied in order to test the
sensitivity of travel times to various models.
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