The following is a summary of what you'll find in this section.

	Science Objectives Science objectives for NASA's ocean altimetry missions and beyond
	El Niño/La Niña & PDO Links related to El Niño/La Niña and the Pacific Decadal Oscillation
	Societal Benefits Society benefits from ocean altimetry data
	Literature Database A searchable database of ocean surface topography-related published works
	Science Team Read about ocean altimetry science and the researchers on the science team
	Monthly Time Series A side-by-side look at sea surface height and sea surface temperature anomalies
	The Tandem Mission Information about the TOPEX/Poseidon/Jason & the Jason-1/Jason-2 tandem missions

To gather long-term information about the world's oceans and currents, orbiting instruments must take extremely precise measurements of the height of the ocean surface - commonly called sea level - above the center of the Earth. This is referred to as ocean surface topography; not to be confused with bathymetry, which is the topographic relief on the bottom of the ocean. Ocean surface topography data contains information that has significant practical applications in such areas as the study of worldwide weather and climate patterns, the monitoring of shoreline evolution, and the protection of our great ocean fisheries. There are many scientists studying this information. The image at right shows the latest satellite ocean surface topography data.

Ocean topography missions like Jason-1 and OSTM/Jason-2 seek to satisfy the following science goals:

• To determine general ocean circulation, and to understand its role in the Earth's climate, and its hydrological and biogeochemical cycles.
• To study the variation of ocean circulation on time scales from seasonal and annual to decadal and the effects on climate change.
• To collaborate with other global ocean monitoring programs to produce routine models of the global ocean for scientific and operational applications.
• To study large-scale ocean tides.
• To study geophysical processes from their effects on ocean surface topography.

Altimeter data are being used as part of a suite of data used as input into dynamic models for long term climate forecasting and prediction. Other data sources include sea surface temperature measurements from satellites, and in-situ measurements from buoys and drifters.

For Jason-1 OSTM/Jason-2, taking measurements and turning them into usable scientific data products involves ground-based verification of the satellite measurements, an elaborate satellite telecommunications system for transmitting and receiving the data from its instruments, and a complex data processing effort involving two NASA centers and the French space agency CNES.

Data from these missions are delivered to customers in map or digital form. Data products are generated for:

• Sea surface height
• Geostrophic velocity vectors
• Wind speed
• Wave height