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Surface Water Ocean Topography (SWOT)

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Status: Current
Mission Category: Earth Systematic Missions Program, Decadal Survey 2007
Launch Date: December 16, 2022

The Surface Water Ocean Topography (SWOT) mission is a proposed NASA mission to make the first global survey of Earth's surface water.

SWOT is being developed by an international group of hydrologists and oceanographers to provide a better understanding of the world’s oceans and its terrestrial surface waters. It will give scientists their first comprehensive view of Earth's freshwater bodies from space and much more detailed measurements of the ocean surface than ever before.

SWOT is a collaboration between NASA and the French space agency, CNES. It builds on the very successful 25-year partnership between the two agencies to use radar altimetry to measure the surface of the ocean. This partnership began with the TOPEX/Poseidon mission.

The SWOT mission is based on a new type of radar called Ka-band radar interferometry. The satellite will fly two radar antennae at either end of a 10-meter (33-foot) mast, allowing it to measure the elevation of the surface along a 120 - kilometer (75-mile)-wide swath below. The new radar system is smaller but similar to the one that flew on NASA's Shuttle Radar Topography Mission, which made high-resolution measurements of Earth's land surface in 2000. On Friday, December 16, at 3:46 a.m., PT, SpaceX launched NASA's SWOT mission to LEO from Space Launch Complex 4E (SLC-4E) at Vandenberg Space Force Base.

Key Surface Water Ocean Topography Facts

Origination: Joint with France
Instruments: Ka- or Ku-Band Radar
Ku-Band Altimeter
MWR (Microwave Radiometer)
Program Scientist(s): Eric Lindstrom
Other Key Personnel: Steve Neeck

Related Publications:

Science Goals:

  • Provide sea surface heights (SSH) and terrestrial water heights over a 120 km wide swath with a +/-10 km gap at the nadir track.
  • Over the deep oceans, provide SSH within each swath with a posting every 2 km x 2 km, and a precision not to exceed 0.5 cm when averaged over the area.
  • Over land, download the raw data for ground processing and produce a water mask able to resolve 100-m rivers and 1-km2 lakes, wetlands, or reservoirs. Associated with this mask will be water level elevations with an accuracy of 10 cm and a slope accuracy of 1 cm/1 km.
  • Cover at least 90 percent of the globe. Gaps are not to exceed 10 percent of Earth's surface

Related Applications:

  • Coastal Management
  • Water Management