The Cyclone Global Navigation Satellite System (CYGNSS) will make frequent and accurate measurements of ocean surface winds throughout the life cycle of tropical storms and hurricanes. The goal is a fundamental improvement in hurricane forecasting. The CYGNSS data will enable scientists to probe key air-sea interaction processes that take place near the core of the storms, which are rapidly changing and play a critical role in the genesis and intensification of hurricanes.
The Cyclone Global Navigation Satellite System (CYGNSS) aims to improve extreme weather prediction.
CYGNSS will measure the surface winds in and near the hurricane inner core, including regions beneath the eye wall and intense inner rain bands that could not previously be measured from space. The CYGNSS measured wind fields, when combined with as-frequent precipitation fields (e.g. produced by the upcoming Global Precipitation Measurement (GPM) core satellite and the current constellation of precipitation imagers), will provide coupled observations of moist atmospheric thermodynamics and ocean surface response, and enable new insights into TC inner core dynamics and energetics.
The CYGNSS constellation consists of 8 small satellite observatories in 500 km circular orbits at an inclination of ~35°. Once in orbit, CYGNSS observatories will receive both direct and reflected signals from Global Positioning System (GPS) satellites. The direct signals pinpoint observatory positions, while the reflected signals respond to ocean surface roughness, from which wind speed is retrieved. Each observatory is capable of measuring 4 simultaneous reflections, resulting in 32 wind measurements per second across the globe. The complete constellation provides gap-free Earth coverage with a revisit time of 1.5 hr (median) and 4.0 hr (mean) over the full +/- 35° latitude region.