Synthetic aperture radar products for the African marine environment

Abstract

Synthetic aperture radars (SAR) are the only instruments in space that can simultaneously provide direct measurements of surface current, wave and wind fields, and their products are used operationally to detect ships and oil spills; to track propagation of swell fields across ocean basins; and to monitor ice motions. At present, there is no facility in southern Africa for processing or disseminating SAR products to the marine community. Synthetic Aperture Radar for Africa (SAR-Africa) is an initiative which aims to develop African capacity for the processing of satellite SAR products to pursue oceanographic research and promote operational applications. In November 2008, the first SAR-Africa workshop was held at the University of Cape Town, where SAR applications, data processing and data limitations were reviewed. A number of presentations highlighted that the coast and shelf seas of southern Africa are an ideal area in which to test applications and further the development of SAR products. The Agulhas Current ecosystem, in particular, supports a high degree of biodiversity and endemism and a range of ecologically-sensitive environments, such as mangroves and coral reefs. Major economic activities along the continental shelf of the Agulhas Current include fishing, oil and mineral exploration as well as intense shipping traffic, with the transport of crude oil from the Middle East to Europe. The Agulhas Current flows along the continental shelf of southern Africa, and is the most intense western boundary current of the southern hemisphere. It transports large volumes of warm water southwards and has an average transport of 70 SV, with typical current velocities of 1–1.5 m s –1 . The current, which is affected by a wide range of meso and sub-mesoscale processes such as rings, eddies, filaments and plumes, 1 is an important component of the global thermohaline circulation 2