  We study the influence of large-scale photospheric motions on the
estabilization of an eruptive filament, observed on October 6, 7, and 8, 2004,
as part of an international observing campaign (JOP 178). Large-scale
horizontal flows were invetigated from a series of MDI full-disc Dopplergrams
and magnetograms. From the Dopplergrams, we tracked supergranular flow patterns
using the local correlation tracking (LCT) technique. We used both LCT and
manual tracking of isolated magnetic elements to obtain horizontal velocities
from magnetograms. We find that the measured flow fields obtained by the
different methods are well-correlated on large scales. The topology of the flow
field changed significantly during the filament eruptive phase, suggesting a
possible coupling between the surface flow field and the coronal magnetic
field. We measured an increase in the shear below the point where the eruption
starts and a decrease in shear after the eruption. We find a pattern in the
large-scale horizontal flows at the solar surface that interact with
differential rotation. We conclude that there is probably a link between
changes in surface flow and the disappearance of the eruptive filament.
