Surface Water and Ocean Topography (SWOT) is the first satellite mission to measure the elevation of nearly all water on Earth’s surface. As a global survey, SWOT will create detailed maps of the water surface topography over the open and coastal oceans, lakes and rivers, reservoirs, and other bodies of water. After two decades of preparation for the mission since its conception by the Wide Swath Ocean Altimeter group in the early 2000s (e.g., Fu and Rodrigues 2003; Alsdorf and Lettenmaier, 2003), SWOT was launched on December 16th 2022, illuminating the night skies of central California at the Vandenberg Space Force Base and commencing a new era in highresolution satellite remote sensing of Earth’s ocean and inland surface waters.
The SWOT observatory uses a combination of radar altimetry and interferometry and was jointly developed by NASA and the Centre National d’Etudes Spatiales (French Space Agency, CNES), with contributions from the Canadian and the United Kingdom Space Agencies. The key instrument on board the SWOT satellite is the Ka-band Radar Interferometer (KaRIn). KaRIn is a first-in-flight demonstration of wide-swath SAR (Synthetic Aperture Radar) interferometry and paves the way for more accurate and comprehensive mapping of Earth’s surface water from space. Using interferometric principles, KaRIn combines multiple radar signals to generate high-resolution 3D maps of the water surface over a wide (120-km) swath. As a result, SWOT observes the location, shape, and evolution of the ocean surface at about 15-km horizontal resolution, which is ten-times finer than the previous Jason-class altimeters; over land SWOT surveys millions of lakes larger than 250 m x 250 m and rivers wider than 100 m across the globe. The first images of Earth’s ocean and inland waters sent by SWOT revealed promising results and indicated higher-than anticipated instrument accuracy.
SWOT’s highly anticipated data are expected to advance a range of Earth science applications, including land hydrology, ocean physics, water and energy cycle, and broader climate science. SWOT will also provide practical information for water resource management, infrastructure planning and development, disaster and hazard response, and other decision-making contexts ranging from agriculture to energy and geopolitics.
The goal of this program element is to select U.S. members of the international SWOT Science Team that will function from 2024 through 2028. Only U.S.-based organizations are eligible to propose to this program element. U.S.-based proposals may include unfunded participants affiliated with foreign organizations. NASA selection of U.S.proposals will be coordinated with CNES selection of proposals from foreign organizations, to ensure continued growth of the international SWOT community, which today includes science team members from 17 countries spanning five continents across the globe that were selected from a previous competition. NASA will provide funding for the selected proposals from U.S.-based institutions and CNES will be responsible for the selection of the international projects. The solicitation of proposals from French and other international investigators will be conducted via its Terre-OcéanSurfaces Continentales-Atmosphère (TOSCA) process.
The overarching objective of the SWOT Science Team is to demonstrate the potential of the SWOT observing capabilities in societally-relevant Earth science studies.
Deadlines:
- Notice of Intent: Nov. 9, 2023
- Proposal: Dec. 15, 2023