Jason-3 will ensure a continuation of the series of measurements supporting meteorology, operational oceanography and the monitoring of the sea-level trend, a key indicator of climate change.
Jason-3 was launched on 17 January 2016, from Vandenberg Air Force Base in California, on board a SpaceX Falcon 9 launcher.
After the launch the Jason-3 and Jason-2 flew in a tandem configuration, about 80 seconds or 500km apart. This allowed for a precise comparison and direct cross calibration between the instruments flying on both platforms.
During this phase, the instruments aboard Jason-3 were fully calibrated and demonstrated performances at least equivalent to those of Jason-2. Based on these results, the satellite was deemed ready for operational service in October 2016.
Jason-3 flies on a non-sun-synchronous low Earth orbit at 66° inclination and 1336 km altitude, optimised to eliminate tidal aliasing from sea surface height and mean sea level measurements.
To improve sampling and spatial coverage, Jason-2 was moved to its final position, on the same orbit but at 162° from Jason-3 — overflying different ocean surfaces and at a different time to Jason-3.
- Measurements of ocean topography — the equivalent of surface pressure in the atmosphere — enable numerical prediction of the three-dimensional ocean, a prerequisite to the development of operational oceanography, in combination with marine meteorology.
- Helping improve monthly forecasts, e.g. heatwaves or sustained heavy rainfall, and seasonal forecasts, e.g. a cold winter or a hot summer, due to the sustained influence of the ocean on the atmosphere.
- Variations of sea level (some mm per year) in our changing climate can only be monitored on global scale by HPOA observations, and ocean surface topography measurements are essential to understand how the ocean stores and redistributes heat, water and carbon in the climate system.
- Altimeter observations are a unique source of ocean surface wind speed measurements for the validation of the new very high resolution (1 to 2 km) regional Numerical Weather Prediction models, to improve short range prediction of high impact weather, such as hurricanes.
"Satellite altimeters have been called one of the most successful oceanographic missions of all time. Their legacy has revolutionised oceanography."
Dr Joshua Willis, Jason-3 Project Scientist, NOAA
The Jason missions use radar altimetry sensors that measure the time a signal takes to bounce off the ocean surface and return to the satellite, to provide global measurements of sea surface height that are accurate to within a few centimetres. This information, combined with GPS and DORIS measurements of the satellite's location, allows complete global mapping of sea surface height once every 10 days.
Only space-based radar altimetry can observe the topography of the ocean surface, a parameter that carries the signature of the ocean currents beneath, and, over longer time scales, that of climate change in terms of variations of mean sea level. Altimetry also measures surface wind speed and the height of ocean waves.
Jason data can help support forecasting for:
- Ship routing
- Maritime industries
- Responding to environmental hazards in coastal areas
- Search and rescue
- Military operations
The Jason-3 programme is built on the same cooperation as Jason-2, involving EUMETSAT, NOAA, CNES and NASA, with Copernicus expected to support the European contribution to operations, as part of its HPOA activity, which also covers contributions to the Jason-CS programme.
Jason-3 follows the same design as Jason-2. It is based on the same Proteus platform delivered by CNES and has the same US and European instruments.
System operations also use the same ground system and cooperation arrangements as Jason-2.
On 1 July 2016 the Jason-3 near-real time (NRT) Operational Geophysical Data Records (OGDR) and the non-time critical (NTC) Interim Geophysical Data Record (IGDR) were released all users.
The OGDRs include estimates of significant wave height, wind speed, and a first estimate of sea surface height based on orbit data and atmospheric corrections available in real time.
They are disseminated to users within three hours of observation. IGDRs are distributed within two days of observation and provide more accurate estimates of sea surface height thanks to improved orbit determination.
Videos on the Jason-3 programme and the applications of Jason-3 satellite data.
Jason 3-Continuing Decades of Ocean Surface MeasurementsNOAA video, introducing the Jason-3 satellite and its mission.
CoastsCNES video, outlining how Jason satellite data is used to monitor coastal erosion and predict flooding.
Marine WildlifeCNES video, illustrating how Jason data is used to track and assist in the protection of marine wildlife.
Sea LevelCNES video, outlining how Jason satellite data is used to monitor global sea levels.
The Water CycleCNES video, illustrating how Jason data is helping us understand the water cycle.
Operational OceanographyCNES video, outlining how Jason satellite data is helping support operational oceanography around the globe.