Lagrangian Drifter Network

A Lagrangian drifter network is an array of free-floating instruments that follow water parcels, sampling the ocean in a frame that moves with the flow rather than at fixed points. Surface drifters with 15 m drogues map near-surface currents; subsurface RAFOS and Argo floats track deeper water using acoustic ranging or pressure. The Global Drifter Program runs about 1300 surface drifters, and trajectory ensembles yield mean currents, eddy diffusivity, and dispersion statistics. Lagrangian data complement the Eulerian record from moorings: a drifter shows where water goes, a mooring shows what passes a point. The network underpins surface velocity climatologies and oil-spill drift models.