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by SWOT last modified May 05, 2015 10:48 AM

Welcome on SWOT space mission French site

(Surface Water and Ocean Topography)




Water is a basic need for humanity. Water cycle studies, observations of oceans, rivers, lakes and wetlands are greatly  needed for the sake of  water management and global change impact evaluation.

Science communities involved in surface water hydrology and ocean surface topography have proposed the space mission SWOT  (Surface Water Ocean Topography ) dedicated to global ocean and surface continental water studies.





Regarding oceanography, the space revolution has already happened ...



► Nadir radar altimeters are providing for 20 years long global measurements of ocean topography.

► These measurements for long time spans of large scale circulation and heath accumulation in ocean have allowed  the discovery that climate is under influence of ocean circulation.

► The radar altimeter has allowed global sea level  measurements, showing the mean rise of the ocean with regional variations.


... but today, data are missing for continental hydrology.



► Surface water measurements are limited to networks of equipments registrating water levels at fixe points in river beds.
► We have only a rough knowledge of variations with space and time of water stocked over continents and running off in rivers.
► Water fluctuations in wetlands and flooding zones are not measured enough, allowing only a crude comprehension of flood process.

► Satellite altimetry is an important complement to direct measurements; But many lakes and rivers are presentely not or badly sampled with flying space missions, because there is no tracks over them, or because data are too noisy.


For both hydrology and oceanography, the main limitation of nadir altimetry is the distance between two tracks (220 to 300 km) avoiding observation of small scale structures of oceanic circulation and missing a lot of  watered surfaces on lands.

To reach ours scientific goals in physical oceanography and  land surface hydrology we need high resolution space measurements of sea and land  waters with global coverage. It is the goal of SWOT program. It is a join program between USA and France, a new step in the long story of cooperation between national agencies, NASA and CNES.


SWOT Key people :



has been announced by NASA for SWOT launch.




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