Coastal storms, hurricanes, and tsunamis are among the most devasting natural hazards in terms of property damage and loss of human life. These are just two of the many types of ocean hazards that have been studied using altimetry data. Direct altimeter measurements – such as wind speed and significant wave heights – are merged with derived information – such as tides and upper ocean heat content – to better understand the timing and impact of coastal storms and hurricanes. The integration of altimetry data into ocean-atmosphere computer models has not only aided short-term prediction of ocean hazards such as storm surge, it has helped scientists assess the vulnerability of our coasts to longer-term changes in climate.
Unrelated to climate, tsunamis are another ocean hazard that have been studied using altimetry data. Triggered by vertical deformation of the seafloor, tsunamis can create deep-sea waves with potential to deliver enormous quantities of water when they reach the shore. Direct observation of tsunami waves is challenging due to timing – they travel at high speeds (around 800 km or 497 mi per hour) – and their relatively small amplitude at sea (i.e., a few to tens of centimeters). Nonetheless, altimetry data have improved models of how tsunami waves propagate through the ocean. And, interestingly, marine gravity and bathymetry data derived from altimetry are used to map seafloor features, including the faults that cause earthquakes.
Another major application of altimetry data to hazards research is prediction of the trajectories of materials carried by ocean currents. This methodology has been applied to track the spread of radioactive materials (e.g., from the Fukushima Daiichi Nuclear Power plant during the March 2011 Tohoku tsunami), oil spills (e.g., Deepwater Horizon event in April 2010), and more persistent types of marine debris such as ocean plastics.
Some of the applications that benefit from satellite altimetry data:
The interactive timeline below provides a brief history of how data from NASA Altimetry Missions have contributed to the study of hazards.
Training and Resources
- Use Cases (Radar Altimetry Tutorial & Toolbox)
- Examples of Altimetry Data Use (Radar Altimetry Tutorial & Toolbox)