We consider the potential for making current mea-
surements from gliders, and present data from a deployment
in early 2007 of lOOOm Slocum electric gliders in the North
West Mediterranean Sea. Three types of current measurement
are considered. First, by comparing the difference between
successive GPS positions, obtained when the glider surfaces,
and dead-reckoned displacements when the glider is submerged,
it is possible to estimate depth averaged horizontal currents
and also surface drift. Second, our gliders were equipped with
Conductivity Temperature Depth sensors, which provided data
used to calculate geostrophic horizontal velocity. Third, from the
measured rate of change of pressure it is possible to quantify the
vertical water velocity as the difference between the measurement
and the expected vertical motion. The latter two both require a
model of the glider motion, which we outline. Horizontal currents
of the order of 30 cm/s were measured in the westward flowing
Northern Current off the south coast of France, with a width and
transport comparable with previous observations using differen
technologies. The accuracy of the depth-averaged currents i
magnitude and direction was limited by the accuracy of the
measured heading of the glider. Measurements of vertical velocit
were made during a time of active convection when the magnitude
of the vertical motion was up to 10 cm/s. We estimate that the
accuracy of the calculated velocity was of the order of 1 cm/s.