CFOSAT mission: presentation, principle of SCAT and SWIM, applications (video)

CFOSAT is a space oceanography mission joinly carried by the french and chinese space agencies. It will monitor at global scale ocean surface winds and waves characteristics. The CFOSAT satellite payload is composed of 2 radar instruments: • SCAT a chinese wind scatterometer • SWIM a french wave scatterometer Principe The satellite is placed on a sun-synchronous orbit at 520 km altitude. Ku-band electromagnetic waves are emitted by each of the two instrument units. At any time of night or day, as well as anyway the weather conditions, the signal goes through the atmosphere and is reflected on the ocean surface. Part of the reflected signal is received back by the instruments allowing to measure ocean surface backscattering properties. The incidence angle selected determines the physical properties of wind or waves. SWIM The SWIM instrument is designed to measure ocean wave statistical properties in direction, wavelength or energy. To this end, it uses 6 beams with incidence angle ranging from 0° to 10° and rotation of the whole system. Each beam footprint is 20 km in diameter. The total swath is being about 180 km wide. SCAT The SCAT instrument is designed to measure the ocean surface winds in intensity and direction. Within incidence angle from 20° to 50°, the beam illuminates a wide ocean area a 1000 km swath alternating the emitted polarization. Applications CFOSAT science telemetry is received for an X-band network composed of French and Chinese ground stations. These data are then processed in China and in France so as to provide the weather forecast centers with usable information such as the sea state with the significant wave heights (SWH), their wavelength and their main propagation direction and ocean surface winds maps exploitable for marine activities. In addition, CFOSAT data are used for more complex applications such as sea state forecast maps or ships routing assistance services. Today, exchanges between ocean and atmosphere are under the spotlight for the whole scientific community. They are of major importance for our climatic system. However, wind and waves interaction at ocean surface are not totally understood. Then improving the forecast of extreme events like hurricanes or big storms is also an important challenge. This cooperation program between France and China is a world premiere and contributes to improving science knowledge. CFOSAT is an asset for a better understanding of the climate of our planet.

Further information: https://www.aviso.altimetry.fr/en/missions/future-missions/cfosat.html

https://youtu.be/RZ_-SkZwo-E