Altimetry satellites are a crucial tool for observing variations in mean sea level. Satellite measurements show a mean sea level rise of around 3.1 mm a year between 1993 and 2012. This global rise is linked to warming caused chiefly by greenhouse gas emissions. Predictions for the 21st century are more alarming, with global warming expected to drive a significant rise in sea level.

Satellite monitoring of Arctic sea ice provides key indicators to assess the extent of climate change and give us a true picture of our planet.

Altimeters can measure sea surface height first and foremost the waves height, which is of prime importance to marine weather forecasters in terms of maritime safety. Wave heights from altimetric measurements are assimilated into sea state forecast models, and improve significantly their predictions.

Our coasts are subjected to changing ocean conditions, with rising sea level, more frequent storms, extreme weather events and erosion to name a few. Satellites have a key role to play in this task.

Altimetry data are key measurements to describe and forecast how ocean conditions are likely to evolve out to several weeks. Many applications are taking advantage of the quality of satellite altimetry data.

Microplastics, oil spill, nuclear waste, source of pollutions are numerous offshore.

Altimetry satellites, by monitoring ocean currents and circulation, can help us to better track all kinds of pollutants and anticipate where they are likely to accumulate.

Jason-3 has been successfully launched last 17 January, 2016. Although its final orbit will be reached in a few days, its data are expected by users to serve a multitude of applications. It extends the high-precision ocean altimetry data record to support climate monitoring, operational oceanography and seasonal forecasting. Jason-3 is the result of a joint effort by national agencies Cnes, Nasa and operaitonal agencies, Eumetsat and Noaa,