Global sea level rise is an obvious indicator of climate change in the ocean, a trend that is impacting many coastal populations. Before the launch of TOPEX/Poseidon in 1992, only tide gauges were capable of measuring the trend in global sea level and yielded an estimate of about 15 cm (6 in) rise over the twentieth century. For nearly three decades, satellite altimeters have provided a precise continuous record of global sea level with excellent spatial and temporal resolution. During this period, the rate of global sea level rise has been about 3.4 mm (0.13 in) per year, about twice the estimate from tide gauges during the previous century.
Changes in Earth's climate also has other consequences for our ocean. Although the concentration of carbon dioxide (CO2) in both the atmosphere and ocean have risen over the past decades, the rates of air-sea transfer of CO2 depend on conditions such as breaking waves. Data from satellite altimeters have been used to generate global maps of CO2 flux and conclude that the subarctic North Atlantic is the greatest oceanic CO2 sink worldwide. As a region where cold, dense waters sink to help drive deep, north-to-south (i.e., meridional) circulation, the North Atlantic Ocean is a key region of interest for climate science. Altimetry data have been used to study many aspects of this circulation such as updating climate models as well as characterizing variability of associated currents and across-basin transport.
Some of the applications that benefit from satellite altimetry data:
The interactives below show climate trends related to sea level rise.
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)