The  Chinese  (CNSA)  and  French  (Cnes)  Space Agencies  jointly  plan  a satellite mission devoted  to the  monitoring of the  ocean surface  wind and wave, and related ocean and atmospheric science and applications: CFOSAT project (Chinese-French Oceanic SATellite).

The  CFOSAT embark  two main instruments: the French radar SWIM  (Surface Wave Investigation and Monitoring) to determine the direction, amplitude and wavelength of surface waves and the Chinese scatterometer SCAT to measure wind speed and direction. 


The mission objective is to measure at the global scale ocean surface wind and waves spectral properties for the following applications:

- Main Objective:      
     - atmospheric, oceanic  and wave forecast systems,       
     - wind and wave climatology,    
     - characterization of  processes affecting surface waves,      
     - characterization and modeling of ocean/atmosphere coupling

- Secondary objective:
     - land and sea ice characterization (Sun synchronous polar orbit)
     - sea ice and ice cover
     - land surface (variations of humidity and roughness)

Satellite  CFOSAT
Launch on  29/10/2018
End Date 
Altitude  ~500 km
Inclination  ~97.5°
Repetitivity  13 days
Agency  Cnes-CNSA
Goals  Measure sea state (wind/wave)

Generation and access to products

The ground segment is shared between Chinese (Mission and Control centers) and French centers (Instrument mission center and waves and wind mission center). The CWWIC (Cnes Waves & Wind Instrument Center) generates the SWIM and SCAT products until level 2. The SWIM and SCAT products of level 1A and 2 are available here.

How to use the products?

The SWIM product simplified handbook document describes the mains parameters for a first use of the SWIM data. Associated Jupyter notebook and python scripts are available for download here.
The SWIM Product User Guide document gives the detailed description of SWIM product variables.
The SCAT product specification document contains the list of SCAT product variables.

Localisation of Measurements:
Download the user manual with the Google Earth CFOSAT file and the txt file giving the UTC starting dates of each cycle. The combined use of these two files allows the computation of CFOSAT passes over dates and times, within five to ten minutes’ precision, which should be sufficient for product selection or for campaign preparation.

Product qualification

The SWIM Calval Report 2019 document provides users with a summary of the CAL/VAL work carried out until summer 2019 on the instrument and the products. It gives the performance and the limitations of the SWIM products made available at the date of 19 February 2020. Work is still on progress to improve the inverted wave product from SWIM. A new version of the processor should be implemented by April 2020.

Recommendations to CFOSAT users on publication policy:

The first scientific publications on CFOSAT data will be authored by members who participated to the verification and CAL/VAL phase since the satellite launch. Two papers, one on SWIM and one on SCAT are currently under review for publication in IEEE Trans. on Geoscience and Remote Sensing (February 2020). 

It is recommended that all further publications based on CFOSAT data cite one of these first two publications (depending on whether they deal with SCAT or SWIM). The publications co-authored by several members and groups of the Joint Science Team is firmly encouraged.

All the publications and communications based on CFOSAT data have to be forwarded to CNSA and CNES (send to who will transmit) and they all have to acknowledge CNSA and CNES as having ownership of the CFOSAT science products. The acknowledgement sentence is: “All CFOSAT data are provided by courtesy of CNSA and CNES [under science proposals XXX. (XXX=proposal id)]."

Further information: