Hsu (2006), Ocean surface drift by wavelet tracking of SAR images, presented at

Historically, ocean surface feature tracking analyses have been based on data from a single orbital sensor collected over its revisit interval of a lone, low-Earth orbital satellite. Today, ocean surface currents are being derived by performing feature tracking using data from the same type of sensors on different satellites. With all-weather, day/night imaging capability, Synthetic Aperture Radar (SAR) penetrates clouds, smoke, haze, and darkness to acquire high quality images of the Earth’s surface. The ability of a SAR to provide valuable information on the type, condition, and motion of the sea-ice, ships and surface signatures of swells, wind fronts, oil slicks, and eddies has been amply demonstrated [Liu and Wu, 2001]. This makes SAR the frequent sensor of choice for cloudy coastal regions. At present, there are three major synthetic aperture radars in orbit. Radarsat-1, the first Canadian remote sensing satellite, was launched in November 1995. Radarsat-1 has a ScanSAR mode with a 500 km wide swath and a 100 m resolution. The ERS-2, having a conventional SAR with a swath of 100 km and a resolution of 25 m, was launched in April 1995 by ESA. Envisat-1 with an Advanced SAR (either conventional narrow swath or wide swath of 405 km with 150 m resolution) was also launched in March 2002 by ESA. With repeated coverage, spaceborne SAR instruments provide the most efficient means to monitor and study the changes in important elements of the marine environment. Due to high-resolution of SAR data, the coverage of SAR sensor is alway