An international satellite mission led by NASA is scheduled to lift off from Southern California early Thursday as part of a major Earth science project to comprehensively survey the world’s oceans, lakes and rivers for the first time.
The advanced radar satellite, dubbed Swot, is designed to give scientists an unprecedented view of the life-giving fluid that covers 70% of the planet, shedding new light on the mechanics and consequences of climate change.
The Falcon 9 rocket, owned and operated by billionaire Elon Musk’s commercial launch company SpaceXbefore dawn on Thursday from US Space Force Base Vandenberg, about 170 miles (275 kilometers) northwest of Los Angeles, to deliver Swot into orbit.
If all goes as planned, the SUV-sized satellite will be producing research data within several months.
Nearly 20 years in development, Swot incorporates advanced microwave radar technology that scientists say will collect surface height measurements of oceans, lakes, reservoirs and rivers in high-resolution detail in more than 90% of the globe.
“It’s really the first mission to observe almost all of the water on the surface of the planet,” said Ben Hamlington, a scientist at NASA’s Jet Propulsion Laboratory who also leads the NASA Sea Level Change Team.
A major motivation for the mission is to explore how the oceans absorb atmospheric heat and carbon dioxide in a natural process that modulates global temperatures and climate change.
Surveying seas from orbit, Swot is designed to measure subtle differences in surface heights around smaller currents and eddies, where much of the ocean warming and carbon is thought to be occurring. And Swot can do this with 10 times greater accuracy than current technologies, according to JPL.
It is estimated that the oceans have absorbed more than 90% of the excess heat trapped in the Earth’s atmosphere due to human-caused greenhouse gas emissions.
Studying the mechanism by which this happens will help climate scientists answer a key question: “What is the tipping point at which the oceans begin to release massive amounts of heat, rather than absorb it, back into the atmosphere and accelerate global warming, rather than limit it,” she said. Nadia Vinogradova-Schiffer, Swot program scientist at NASA in Washington.
Swot’s ability to discern smaller surface features is also used to study the impact of rising ocean levels on coastlines.
More accurate data along tidal zones may help predict how far floods from inland storm surges can penetrate, as well as how much saltwater will seep into estuaries, wetlands and aquifers.
Taking an inventory of Earth’s water resources again and again during the three-year Swot mission will enable researchers to better track fluctuations in the planet’s rivers and lakes during seasonal changes and major weather events.
Collecting data like this is like “taking the pulse of the world’s water system, so we’ll be able to tell when it’s racing and we’ll be able to tell when it’s slow,” said Tamlin Pavelsky, NASA’s Chief of Freshwater Sciences.
The Swot radar instrument operates on the so-called Ka-band frequency of the microwave spectrum, allowing scans to penetrate cloud cover and darkness over large areas of the Earth. This allows scientists to accurately map their observations in two dimensions regardless of the weather or time of day and cover large geographic areas much more quickly than was previously possible.
By comparison, previous studies of bodies of water have relied on data taken at specific points, such as river or ocean gauges, or from satellites that can only track measurements along a one-dimensional line, requiring scientists to fill in data gaps through extrapolation.
“Instead of giving us the elevation line, it gives us the elevation map, and that’s just a complete game changer,” said Pavelski.
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