NASA mission will provide unprecedented view of Earth’s surface water | NASA

A NASA-led international satellite mission was scheduled to lift off from Southern California early Thursday as part of a major Earth science project to conduct a comprehensive study of the world’s oceans, lakes and rivers for the first time. .

Dubbed Swot, short for “surface water and ocean topography”, the advanced radar satellite is designed to give scientists an unprecedented view of the vital fluid covering 70% of the planet, shedding new light on the mechanics and consequences of climate change.

A Falcon 9 rocket, owned and operated by billionaire Elon Musk’s commercial launch company SpaceXwas scheduled to take off before dawn Thursday from the US Space Force Base at Vandenberg, about 275 km northwest of Los Angeles, to carry Swot into orbit.

If all goes according to plan, the SUV-sized satellite will be producing research data within months.

After nearly 20 years of development, Swot incorporates advanced microwave radar technology that scientists believe will collect height and surface measurements of oceans, lakes, reservoirs and rivers in 90% high definition. of the globe.

“This is really the first mission to observe almost all the water on the surface of the planet,” said Ben Hamlington, a scientist from NASA’s Jet Propulsion Laboratory (JPL) who also leads the level change team. of the sea from NASA.

One of the main goals of the mission is to explore how the oceans absorb atmospheric heat and carbon dioxide in a natural process that moderates global temperatures and climate change.

Scanning the seas from orbit, Swot is designed to accurately measure the fine differences in surface elevation around smaller currents and eddies, where much of the decrease in heat and ocean carbon occurs. And Swot can do it with 10 times the resolution of existing 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 by human-caused greenhouse gas emissions.

Studying the mechanism by which this happens will help climatologists answer a key question: “What is the turning point at which the oceans begin to release, rather than absorb, massive amounts of heat into the atmosphere and to accelerate global warming, rather than limit it?” said Nadya Vinogradova Shiffer, Swot program scientist at NASA in Washington.

Swot’s ability to discern smaller surface features can also be used to study the impact of sea level rise on coastlines.

More accurate data along tidal zones would help predict how far inland storm surge flooding can penetrate, as well as the extent of saltwater intrusion into estuaries, wetlands and underground aquifers.

Repeated inventorying of Earth’s water resources during Swot’s three-year mission will allow researchers to better track fluctuations in the planet’s rivers and lakes during seasonal changes and major weather events.

Tamlin Pavelsky, NASA’s chief freshwater scientist for Swot, said collecting such data is like “taking the pulse of the global water system, so we can see when it’s getting carried away and we can see when it is slow”. .

Swot’s radar instrument operates at the so-called Ka-band frequency of the microwave spectrum, allowing scans to penetrate cloud cover and darkness over large swaths of the Earth. This allows scientists to accurately map their observations in two dimensions, independent of weather or time of day, and to cover large geographic areas much faster than before.

In comparison, earlier studies of water masses 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, forcing scientists to fill data gaps by extrapolation.

“Rather than giving us a line of elevations, it gives us a map of elevations, and that’s a complete game-changer,” Pavelsky said.

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