Over the past 28 years, the simultaneous operation of several satellite altimeter missions – along with the development of data merging techniques – have provided unique capabilities to observe the ocean in an operational manner. Near-real-time high-resolution global sea level anomaly maps have been routinely produced as part of the SSALTO/DUACS system. These maps are now widely used by the oceanographic community and have contributed to a much better understanding and recognition of the role and importance of ocean mesoscale dynamics.
Altimetry studies are closely linked with in-situ ocean observation systems, the most important of which is Argo, a global array of profiling floats that measure temperature and salinity to depths of 2000 m. For example, altimeters have shown that global sea level has been rising about 3 mm per year. Argo data have been used to understand how ocean heat storage has contributed to sea level rise. The evolution of satellite altimetry and concomitant deployment of Argo floats were essential to establish global operational oceanography. In fact, today's ocean analysis and forecasting models are strongly dependent on the availability of multiple altimeter data and Argo observations.
Remote sensing and in-situ data have been routinely assimilated in global and regional ocean models to provide an integrated description of the ocean state. Products and services have been developed for a wide range of applications: marine environment monitoring, weather forecasting, seasonal and climate prediction, ocean research, maritime safety and pollution forecasting, national security, the oil and gas industry, fisheries management and coastal and shelf-sea forecasting.
Some of the applications that benefit from satellite altimetry data:
Satellite altimeters have been in earth orbit since the mid 1970s. To be useful for operational oceanography (i.e., resolve ocean variability), however, altimeters needed the sum of their orbit and altimeter errors to be less than 10 cm. Roll your cursor over the interactive image below to learn more.
The future of high-resolution satellite altimetry will continue with the Jason Continuity of Service (Jason-CS) mission on the Sentinel-6 spacecraft, an international partnership between the U.S. and Europe. Jason-CS/Sentinel-6 will include two identical satellites scheduled to launch in 2020 (Michael Freilich) and 2025 (satellite B).
Training and Resources
- NASA Sea Level Change Data Analysis Tool – Beta Version
- NOAA Sea Level Rise Viewer
- Underwater: Rising Seas, Chronic Floods, and Implications for U.S. Coastal Real Estate
- Use Cases (Radar Altimetry Tutorial & Toolbox)
- Examples of Altimetry Data Use (Radar Altimetry Tutorial & Toolbox)