Joint Development to Improve Hurricane Forecast Accuracy
Shawn Martin | October 24, 2017Source: CNES
A joint development between the Centre National d'Etudes Spatiales (CNES) and the China National Space Administration (CNSA) is devoted to the study of physical characteristics of wind and waves. The two government agencies of France and China are developing CFOSAT (China-France Oceanography SATellite) with hopes of using the data to improve hurricane and cyclone forecast accuracy in years to come.
The 1,450-pound satellite will carry two radar instruments. One is a wave scatterometer, SWIM (Surface Waves Investigation and Monitoring), supplied by CNES, and the other a wind-field scatterometer SCAT (wind SCAT-terometer) supplied by CNSA. It will be launched into a sun-synchronous orbit at an altitude of 520 kilometers in 2018.
France has been at the forefront in the field of wave analysis. Their SWIM instrument, which is being developed by Thales Alenia Space with oversight and funding from CNES, will incorporate six rotating beams to measure surface wave properties. The instrument is a real-aperture radar (RAR) system that operates in the Ku-band (13.575 gigahertz). It incorporates a multi-incidence concept where several off-nadir incidence angles ranging from 2 to 10 degrees will sweep a pseudo-circle with a diameter ranging from 18 to 90 kilometers.
The measurement principles used to derive the spectra of ocean waves from this real-aperture radar has been demonstrated by airborne systems developed by both NASA and France. There is some ambiguity in the wave propagation direction that can be corrected for while it will measure directional ocean wave spectra and statistics of wave slopes with range and accuracy similar to other radar-altimeters.
CFOSAT is currently slated for launch in December of 2018 with an end of life date of December of 2021. The three-year mission to monitor surface wave height and spectrum as well as ocean surface winds has the primary objective of improving sea-state forecasts, while the optimistic outlook is to yield new insights into ocean-atmosphere interactions that could improve our understanding of climate change.