At night we deployed a second drifter array in a tight configuration (separated by approximately 1km). At each release location, we deployed 4 drifters — one near surface and the others with drogue depths of 10,30,50m. The separation of these drifters in time, would give an estimate of the vertical shear in the flow. The tight array would help capture the effect of small-scale processes.
For the drifters with a 50 m deep drogue, we used a peg-board to unravel the line between the drogue and the surface buoy.