Remote sensing applications of HF skywave radar: The Australian experience

Australia has conducted research into over-the-horizon radar (OTHR) for almost sixty years. Early programs focused exclusively on military capabilities, such as the detection of aircraft, missiles and ships, but in 1974 a team was formed to design a new OTHR for which a remote sensing mission was proposed. Oceanic wind mapping experiments in 1977-78 yielded promising results so remote sensing became a recognisedmission assigned to the new radar, known as Jindalee Stage B. This capability was progressively expanded over the period 1982-87 to include mapping of wave height and other oceanographic variables. A real-time data link to the Australian Bureau of Meteorology was set up in 1985, providing daily wind direction maps covering over one million square kilometres of the NW Indian Ocean, the Timor Sea and the Arafura Sea. In concert with user-focused remote sensing programs, investigations were undertaken to gain a detailed understanding of issues relating to propagation, system calibration, radar resource management and scheduling. Many theoretical studies and radar experiments were conducted to assess the radar’s ability to measure ever more ambitious geophysical phenomena, ranging from oil spills and tropical rainfall to cyclogenesis and volcanic activity. Inevitably, as the radar evolved into a facility owned and operated by the Royal Australian Air Force, the remote sensing mission had to compete with surveillance tasks with higher priorities and the quality of the routine service provided to the Bureau of Meteorology deteriorated, eventually being terminated after a decade of activity. Despite this, the knowledge acquired and the practical lessons learned remain valid today and may be of value to other OTHR programs.