Ocean currents

Ocean currents covers surface and upper-ocean circulation: the direction and speed of water movement that affects routing, search and rescue, pollutant drift, ecosystem transport, and climate variability. In satellite workflows the current is usually not observed as a visible object. It is estimated from sea-surface height gradients, wind forcing, sea-surface temperature structure, and model or in-situ constraints.^[1][2]

For basin-scale circulation, radar altimetry is the primary EO route because sea-surface-height gradients constrain geostrophic flow. Operational products then fuse altimetry with SST, winds, in-situ observations, and model physics to produce gridded surface or 3D velocity fields.^[1][3]

SAR products can add local ocean context through wind, swell, and radial-velocity variables, but the catalogue should keep that separate from a dedicated SAR Doppler current methodology until the method layer has a clean retrieval-physics row.^[4]