Jason 3, the sea surface height "mesurer"


The French-US altimetric satellite that measures sea surface to an accuracy of 4cm - a warning system for El Nino


Launched by NASA-NOAA and manoeuverd in orbit by CNES Toulouse


Joint project of:

NOAA, NASA, Centre National d'Etudes Spatiales (CNES, France’s governmental space agency) and European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).



Jason 3 Launch in January 2016


#Jason3: New satellite launched to monitor sea level rise & help forecast storms' intensity: ow.ly/XcMEy



Excerpts via BBC:

  • "Jason-3 will measure the shape of the global sea surface to an accuracy of better than 4cm."
  • "It will track currents, tides, winds, wave heights, and will help forecast the intensity of storms."
  • "The Jason satellites act as an early warning system for El Niño by detecting the developing bulge in surface waters associated with the warming."



Le lancement réussi pour #Jason3! Ce satellite franco-américain permettra de mesurer l'élévation des océans. #Climat pic.twitter.com/lMWZ3i2kVB


CNES Retweeted

[blog] #Jason3 le mesureur des mers bientôt en orbite. Lancement dimanche #falcon9 @SpaceX http://wp.me/pnfD1-2RE 




Jason 3 Mode of Operation


2016-03-22  (#WorldWaterDay)

Scientists use satellites to measure world's #water from space! Learn how @ go.usa.gov/ckK6q #WorldWaterDay






Jason 3 has produced its first map




"Just over a month after launch, Jason-3, a U.S.-European oceanography satellite mission with NASA participation, has produced its first complete science map of global sea surface height, capturing the current signal of the 2015-16 El Niño."







#Jason3 a commencé sa mission de mesure de la hauteur des océans et a détecté El Niño dans le Pacifique


#Jason3 has returned its first full map of sea surface height! Read the full story at go.usa.gov/cGJ8B pic.twitter.com/XFj9KhioqZ


Launched in January, #Jason3 began mapping global sea surface height, captures El Niño: http://go.nasa.gov/1Lrte5T 





What is on board the altimetric satellite Jason 3?


The primary instrument onboard Jason-3 is its radar altimeter.



cf. CNES AVISO site



(CNES image from above link)




Information from NOAA Satellite and Information Service link and the above CNES link


> An altimeter (Poseidon-3): antenna that emits a radiowave and receives it back


An altimeter provided by CNES. It has an antenna which emits a radar beam or radiowave/microwave that travels to the Earth surface and is then reflected back (to the antenna). “By measuring the round-trip travel time of the emitted beam, and by using the precise location of the satellite, surface altitude can then be derived within a few centimeters.”


Additional information from NOAA factsheet:


"Poseidon-3 emits pulses at two frequencies (13.6 GHz in the Ku band and 5.3 GHz in the C band) to measure very accurately the distance from the satellite to the sea surface and then to derive the surface altitude(within a few centimeters) using its precise location of the satellite. The two frequencies are used to determine the atmospheric electron content. Free electrons in the atmosphere can delay the signal’s return, which affects the radar signal path delay and measurement accuracy. The delay is directly related to the radar frequency, so the difference between the two measurements can be used to determine atmospheric electron content. These two frequencies also serve to detect the rain events. The strength and shape of the returning signal also provides information on wind speed and the height of ocean waves."



> A meter of radiowaves (from earth) allowing to calculate atmospheric water in liquid and vapor form that delays the altimeter signal


from NOAA factsheet

Provided by NASA, "AMR-2 is a passive microwave radiometer that measures radiation from Earth's surface (brightness temperatures) at three frequencies (18.7, 23.8, and 34 GHz). These different measurements are combined to determine atmospheric water vapor and liquid water content. Once the water content is known, it is possible to determine the correction to be applied to the altimeter for radar signal path delays (the brightness temperatures are converted to path-delay information)."


"The 23.8 GHz channel is the primary water vapor sensor, the 34 GHz channel provides a correction for non-raining clouds, and the 18.7 GHz channel provides the correction for effects of wind-induced enhancements in the sea surface background emission."



> Three location systems

Determination of orbit with an accuracy of 1-2cm



>> GPS Receiver supplied by NASA

>> DORIS (Doppler-based) supplied by CNES

>> LRA (Laser Tracking) supplied by NASA




Jason 3 ready to take over crucial ocean monitoring role





Jason-3 2015 illustration (crop).jpg





World Meteorological Day


Happy #WorldMeteorlogicalDay! Forecasting the daily weather starts not on Earth but in space! Watch youtu.be/S7pQ1NahWko to find out how