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The first mission to measure almost all of the water on the Earth’s surface has started.
The international surface water and ocean topography mission, known as SWOT, lifted off from Vandenberg Space Force Base in California at 6:46 a.m. ET on Friday aboard a SpaceX Falcon 9 rocket. The rocket’s first stage successfully landed back on Earth at 6:54 am ET.
Live coverage began at 6:00 a.m. ET on NASA’s website.
The mission, a joint effort by NASA and France’s Center National d’Études Spatiales space agency, will study water on more than 90% of the Earth’s surface and measure water levels in bodies of fresh water and in the oceans. The two agencies have been working together to monitor Earth’s oceans for decades – and SWOT is the next step in their partnership.
Insights from the SWOT measurements will reveal how oceans affect climate change and how global warming affects lakes, rivers and reservoirs. The satellite’s data can also help communities better prepare for floods and other water-related disasters that are increasing due to the climate crisis.
While water is vital to the survival of life on Earth, it also shapes our weather and climate as it stores and transports carbon and heat trapped in the atmosphere by greenhouse gas emissions. Surveying this resource can help scientists understand the global water balance — assessing the major sources, how those sources are changing, and what impact they will have on different environments.
A key question scientists have concerns the exchange of heat between Earth’s atmosphere and the global ocean and how it might accelerate global warming.
“We’ll be able to see things that we just couldn’t see before,” said Benjamin Hamlington, research scientist with the Sea Level and Ice Group at NASA’s Jet Propulsion Laboratory.
“We’re going to be able to trace the movement of water between ocean and land around the Earth, make some of those connections, and really understand where water is at any given point in time.” This is really critical because we know that the hydrological cycle will accelerate with climate change. That means some locations have too much water, others too little.”
The satellite’s instruments will collect detailed, high-resolution data on freshwater and marine features.
After years of development, SWOT’s Ka-band radar interferometer, or KaRIn for short, is ready to fly. The instrument will be able to detect features up to 10 times smaller than those captured by sea level satellites.
For example, current ground and satellite monitoring only collects data on a few thousand of the world’s largest lakes, while SWOT will increase that number to over 1 million lakes.
Researchers studying bodies of water have had to rely on instruments that take measurements at specific locations, such as river or ocean gauges. Similarly, previous space-based satellites have collected more limited data that cannot plumb the true depths of Earth’s waters. An example of an impediment to collecting accurate readings is that steep-banked rivers do not appear wider or narrower, even when more water is flowing through them.
But the radar instrument KaRIn can collect readings through cloud cover and the darkness of the night. The two antennas are positioned at either end of a 33 foot (10 meter) boom of the satellite. These antennas send radar pulses to the water surface and receive signals back.
“For freshwater, this will be a quantum leap in terms of our knowledge,” said Daniel Esteban-Fernandez, KaRIn instrument manager at NASA’s Jet Propulsion Laboratory in Pasadena, California, in a statement.
The spacecraft will look at almost all rivers wider than 100 meters and map them in 3D for the first time, as well as measure ocean features less than 100 kilometers (60 miles) in diameter.
“SWOT will really allow us to understand how the volume of water in our rivers and lakes is changing around the world,” said Tamlin Pavelsky, NASA Freshwater SWOT Scientist at the University of North Carolina, Chapel Hill. “It’s going to be a real game changer.”
Data from SWOT can help researchers fill knowledge gaps when trying to understand the impact of the climate crisis, e.g. B. how sea levels are shifting along coasts and areas that may be more prone to flooding to better predict future rising water levels.
The climate crisis is also promoting extreme weather patterns, including droughts and downpours. The satellite’s instruments can monitor both and provide important information for disaster risk reduction and water management authorities.
One place that could particularly benefit from SWOT monitoring is Alaska. Though the state sits on the edge of the Arctic Circle, it also has about 40% of the United States’ surface water resources, including more than 12,000 rivers and hundreds of thousands of lakes. The area’s size and rugged terrain, as well as general inaccessibility, have hampered water measurements in Alaska.
“SWOT will allow us to see what’s going on hydrologically in Alaska in a way we’ve never done before,” Pavelsky said.
“This is important because Alaska, which is in the Arctic, is also the place in the United States that is currently experiencing the most severe climate change. If you want to know why this is important, think about how many resources we get from Alaska.”
The range of the SWOT mission means the satellite will be able to regularly monitor other areas of the world where water resources have previously been difficult to estimate.
“It will transform our ability to provide information that will ultimately improve the daily lives and livelihoods of almost everyone here on Earth,” Hamlington said.