Microwave Measurement of the Wind Vector over Sea by Airborne Radars

The oceans of the Earth work in concert with the atmosphere to control and regulate the environment. Fed by the sun, the interaction of land, ocean, and atmosphere produces the phenomenon of weather and climate. Only in the past half-century meteorologists have begun to understand weather patterns well enough to produce relatively accurate, although limited, forecasts of future weather patterns. One limitation of predicting future weather is that meteorologists do not adequately know the current weather. An accurate understanding of current conditions over the ocean is required to predict future weather patterns. Until recently, detailed local oceanic weather conditions were available only from sparsely arrayed weather stations, ships along commercial shipping lanes and sparsely distributed oceans buoys (Long, et al, 1976). The development of satellite and airborne remote sensing has improved the situation significantly. Satellite remote sensing has demonstrated its potential to provide measurements of weather conditions on a global scale as well as airborne remote sensing on a local scale. Measurements of surface wind vector and wave height are assimilated into regional and global numerical weather and wave models, thereby extending and improving our ability to predict future weather patterns and sea/ocean surface conditions on many scales. A pilot also needs operational information about wind over sea as well as wave height to provide safety of hydroplane landing on water. Many researchers solve the problem of remote measuring of the wind vector over sea actively (Moore & Fung, 1979), (Melnik, 1980), (Chelton & McCabe, 1985), (Feindt, et al, 1986), (Masuko, et al, 1986), (Wismann, 1989), (Hildebrand, 1994), (Carswell, et al, 1994). On the global scale, the information about sea waves and wind, in general, could be obtained from a satellite using active microwave instruments: Scatterometer, Synthetic Aperture Radar (SAR) and Radar Altimeter. However, for the local numerical weather and wave 26