NASA CYGNSS Mission Update; A Pathfinder for Operational GNSS Scatterometry Remote Sensing Applications

Advancements in electronics and nano-satellite technologies combined with recent modeling development are enabling a new class of remote sensing capabilities that present more cost effective solutions to existing problems while opening new applications of Earth remote sensing. Increased temporal sampling on both a global and macro scale is one such example of capability increase enabled by nano- and micro-satellites. NASA's CYclone Global Navigation Satellite System (CYGNSS), recently launched and commissioned, uses passive GNSS-based bi-static scatterometry and a 8-spacecraft constellation to provide breakthrough remote sensing of ocean wave and wind data with unprecedented temporal resolution across the full dynamic range of ocean wind speeds in all precipitating conditions. CYGNSS will provide data to address what are thought to be the principle deficiencies with current tropical cyclone intensity forecasts: inadequate observations and modeling of the inner core. The inadequacy in observations results from two causes: 1) Much of the inner core ocean surface is obscured from conventional remote sensing instruments by intense precipitation in the eye wall and inner rain bands. 2) The rapidly evolving (genesis and intensification) stages of the tropical cyclone life cycle are poorly sampled in time by conventional polar-orbiting, wide-swath surface wind imagers. Numerous additional Earth remote sensing applications can also benefit from the cost effective high spatial and temporal sampling capabilities of GNSS remote sensing. These applications include monitoring of rough and dangerous sea states, global observations of sea ice cover and extent, meso-scale ocean circulation studies, and near surface soil moisture observations. This paper provides a summary of early CYGNSS performance and a primer of other GNSS scatterometry based remote sensing applications.