DULUTH — A new satellite launched earlier this month will focus on water across the Earth, including the Great Lakes, thanks to a University of Minnesota Duluth scientist.
Sam Kelly, an associate professor with the Large Lakes Observatory and the Physics & Astronomy Department at UMD, has been involved in the Surface Water and Ocean Topography, or SWOT, satellite project since 2015 and helped convince NASA to include Great Lakes research as part of the mission.
The satellite, built by the French space agency and launched Dec. 16 at Vandenberg Space Force Base in California, riding on a Space-X rocket, is expected to relay data that’s critical in studying how the Earth’s water moves, how water stores heat and carbon and water’s role in climate change.
It’s also expected to relay the most accurate water level data ever recorded, measuring the height of every ocean, river and lake within a millimeter or two.
The $1.2 billion SWOT program actually began 20 years ago and built slowly as scientists from around the world offered proposals on how water should be measured and studied. Kelly, 40, is part of the mission’s science team that includes more than 100 water scientists from 20 nations around the world. Another team is comprised of engineers who assembled the devices inside the satellite.
ADVERTISEMENT
Kelly's original proposal accepted by NASA in 2015 was to use the satellite data to look at ocean tides — his area of expertise — as part of the broader effort to measure ocean water levels.
“But I realized after sitting through so many meetings that we were missing a big part of the world’s fresh water right here in the Great Lakes,” Kelly told the News Tribune. “We had half the team as hydrologists looking at rivers and smaller lakes, and half the team as oceanographers looking at the oceans, and nobody was talking about the Great Lakes. They just sort of fell through the cracks.”
So last summer, Kelly offered NASA another proposal — to use the new satellites data to study currents in the Great Lakes — and NASA agreed. Currents have been well-studied in the lakes, but so far only at certain points and at certain times when and where devices can be lowered into the water. The satellite will be able to measure current across all the lakes all the time, Kelly noted.
“It's kind an expensive effort now, and we only get data from a few areas. We should be able to map all of the lakes’ currents now based on the new data we get,” said Kelly, a Bloomington, Minnesota, native who has been working at UMD since 2014.
Knowing where the currents go will help scientists track pollution, such as the nutrients that can cause algae blooms, a growing concern for fish and humans on the big lakes.
SWOT will cover the entire Earth’s surface once every 21 days, sending back about 1 terabyte of unprocessed data per day.
The scientific heart of the spacecraft is an innovative instrument called the ka-band radar interferometer, which marks a major technological advance. Radar signals will pulse off the water’s surface and the return signals will come in through two antennas on either side of the spacecraft. This system — one signal, two antennas — will precisely determine the height of the water’s surface across two swaths at a time, each of them 30 miles wide.
The measurements from the spacecraft’s science instruments will also help communities monitor and plan for changing water resources — floods and droughts — as well as the effects of rising sea levels.
ADVERTISEMENT
The satellite will produce high resolution maps of Earth’s oceans and will be able to measure, within a few millimeters, the height of every lake on earth that is more than 1 kilometer wide.
“There are thousands of lakes in the Canadian arctic that we don’t know much about,” said Kelly. “We’ll even be able to measure the slope of rivers. It’s going to provide a crazy amount of information for water scientists.”
Scientists also will use the data to see if and when Earth’s oceans stop absorbing heat and start releasing it back into the atmosphere, a pattern predicted to rapidly speed-up climate change and impact drought and flood cycles.
SWOT data also will help disaster preparedness agencies, universities, civil engineers and others who need to track water in their local areas. And, the information will also help industries, like shipping, by providing measurements of water levels along rivers, as well as ocean conditions, including tides, currents and storm surges.
SWOT is a joint mission developed by NASA and the French space agency Centre National d’Études Spatiales with contributions from the Canadian Space Agency and the UK Space Agency.
The Trust Project
