Monitoring the world's oceans has proven to be challenging in the past because of their size, remoteness, and the lack of instrumentation capable of such observational coverage. Until now, ocean surface feature tracking analyses have been based on data from a lone, low-Earth orbital satellite—images were collected from a single orbital sensor with repeat passes over the same ocean surface. This process was insufficient and incapable to track ocean features due to the satellite's long revisit interval that could not capture the daily complications of surface ocean circulation.
Today, ocean surface currents are being derived much more efficiently by performing ‘feature tracking,’ which uses data from the same types of sensors on different satellites to simultaneously monitor ocean surface phenomenon. In particular, tracking results indicate that multiple synthetic aperture radar (SAR) images overlapped in a short time can be used to derive ocean surface drift, and can help to identify oceanic processes.