Drifting buoys are a primary tool used by the oceanographic community to measure ocean surface circulation at unprecedented resolution. A drifter is composed of a surface float, which includes a transmitter to relay data via satellite, and a thermometer that reads temperature a few centimeters below the air-sea interface. The surface float is tethered to a holey sock drogue (a.k.a. “sea anchor”), centered at 15 m depth. The drifter follows the ocean surface current flow integrated over the drogue depth.