9.1.1 Satellite SARs

Synthetic aperture radar imagery from satellites and aircraft has a high spatial resolution and is independent of light and clouds. Nearly real-time information and a comprehensive SAR image analysis is of importance not only for scientific studies, but also because it has a practical significance providing information for companies dealing with off-shore oil and gas exploration, deep-ocean mining, fishing, marine transportation, weather forecast, etc. ^[65]. In 1972 the NASA Office of Applications initiated the Earth and Oceans Dynamics Applications Program for the development of techniques of global monitoring of oceanographic phenomena and the design of an operational ocean dynamics monitoring system. Satellite SAR studies of the earth environment began in 1978, when the first series of images was obtained by the SEASAT during its 3 month's operation. This L-band horizontally polarised radar operated at a wavelength of 23 cm at an incidence angle of 20 . It was primarily designed for ocean wave imaging, although SAR imagery was also acquired over ice and terrestrial surfaces. It demonstrated the potential of satellite radar data in scientific and operative applications. The SEASAT data supported the notion that wind and wave conditions over the ocean could be measured from a satellite with an accuracy comparable to that achieved from surface platforms ^[5]. Various SAR instruments operating at different wavelengths, polarisations and incidence angles were mounted on bound of Space Shuttles (Table 9.1). In November 1981 and October 1984, the SIR-A and SIR-B radars,...