The AEOLIS program: prospects for future low-cost, space-borne vector wind sensors

The ocean surface wind speed and direction play important roles in meteorology, oceanography, climatology, and operational weather forecasting. Currently, global ocean vector wind measurements are derived from costly active microwave radars, such as the ERS-1 scatterometer and the soon to be launched NASA scatterometer (NSCAT). Recent work in the former Soviet Union and analysis of Special Sensor Microwave/Imager data both reveal wind direction signals in passive microwave data. To determine the limits of passive microwave vector wind remote sensing, the All-weather, Earth-observing, Ocean, Land, Ice Sensor (AEOLIS) program was established. This program consists of laboratory and theoretical studies augmented by analysis of existing space-based data sets and an aggressive aircraft instrument development program. Preliminary results show detectable wind direction signals over the observed wind speed range of 2 to 9 m/s. The state-of-the-art knowledge about this relatively new, passive microwave, vector-wind remote sensing technology is presented.