Meridional flow measurements from 15 years of GONG spherical harmonic time series. |
Auteur | Leibacher John |
Institution | National Solar Observatory |
Theme | Low degree solar and stellar seismology |
| Auteur(s) supplémentaire(s) | Shukiron Kholikov, Frank, Hill |
|
Abstract | We present the results of a meridional flow time distance analysis based on GONG data. In order to increase the signal-to-noise ratio, and to
reduce contamination from other modes, we utilized $it{low}$-$it{m}$ filtering technique. This filtering method seems to be capable of extending the meridional flow measurements to the deep layers of the convection zone, down to 0.7R$_odot$. Our preliminary results indicate that the achieved precision is very close to that required to measure the reverse flow down to the base of the solar convection zone where it is expected to be situated. To avoid projection effects at high latitudes we analyze extreme B-angle time periods separately. We discuss the significance of temporal variations of meridional flow in presence of additional flows around active regions and rojection
artifacts at high latitudes. |
