  The atmosphere of Saturn's largest moon Titan is driven by photochemistry,
charged particle precipitation from Saturn's upstream magnetosphere, and
presumably by the diffusion of the magnetospheric field into the outer
ionosphere, amongst other processes. Ion pickup, controlled by the upstream
convection electric field, plays a role in the loss of this atmosphere. The
interaction of Titan with Saturn's magnetosphere results in the formation of a
flow-induced magnetosphere. The upstream magnetoplasma environment of Titan is
a complex and highly variable system and significant quasi-periodic modulations
of the plasma in this region of Saturn's magnetosphere have been reported. In
this paper we quantitatively investigate the effect of these quasi-periodic
modulations on the convection electric field at Titan. We show that the
electric field can be significantly perturbed away from the nominal radial
orientation inferred from Voyager 1 observations, and demonstrate that upstream
categorisation schemes must be used with care when undertaking quantitative
studies of Titan's magnetospheric interaction, particularly where assumptions
regarding the orientation of the convection electric field are made.
