A large-antenna microwave radiometer-scatterometer concept for ocean salinity and soil moisture sensing

Microwave radiometry and scatterometry are established techniques for surfa ce remote sensing applications. Some applications, such as measurement of s ea surface salinity (SSS), sea surface temperature, (SST), and soil moistur e, require low frequency observations (similar to6 GHZ and below) for good sensitivity, and sensors with large antennas to achieve adequate spatial re solution. Potentially, benefits can he obtained by observing simultaneously with passive and active channels, at similar frequencies, viewing angles, and spatial resolutions, making use of the complementary information contai ned in the emissivity and backscattering signatures of land and ocean targe ts. in this study, we investigate a concept for combined passive and arrive multichannel sensing with high spatial resolution, high measurement sensit ivity, and wide swath for frequent global coverage. The system consists of a lightweight, rotating, deployable mesh antenna with offset feeds, The sys tem specifications are designed primarily for the measurement of sea surfac e salinity, since this application drives the precision and calibration req uirements and, like soil moisture, is a science measurement for which no sp aceborne capability currently exists. Demonstration of a capability for sea surface salinity will enhance the potential of this large antenna concept for other applications such as soil moisture and, by including higher frequ encies, high resolution measurements of ocean winds, precipitation, sea-sur face temperature, and sea-ice.