An international satellite mission led by NASA is set to conduct a comprehensive survey of the world’s oceans, lakes and rivers for the first time.
Key points:
- The satellite is called SWOT, which stands for Surface Water and Ocean Topography
- It will be launched into orbit with the help of Elon Musk’s commercial launch company, SpaceX
- Scientists hope the survey can shed more light on climate change, among other things
The advanced radar satellite, called SWOT (Surface Water and Ocean Topography), is designed to give scientists an unprecedented view of the fluid that covers 70% of the planet.
The survey may shed 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 SpaceX, will lift off from California before dawn Thursday to carry SWOT into orbit.
If all goes according to plan, the SUV-sized satellite will produce research data within a few 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-definition detail over 90% of the planet .
The data will be collected from radar sweeps of the planet at least twice every 21 days.
According to the researchers, this data will improve ocean circulation models, strengthen weather and climate forecasts and help manage scarce fresh water supplies in drought-stricken regions.
The satellite was designed and built at NASA’s Jet Propulsion Laboratory (JPL) near Los Angeles.
Developed by the US space agency in collaboration with its counterparts in France and Canada, SWOT was one of 15 missions listed by the National Research Council as projects that NASA should undertake in the next decade.
“It’s really the first mission to observe almost all the water on the planet’s surface,” said JPL scientist Ben Hamlington, who also leads NASA’s Sea Level Change Team.
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.
Exploring the seas from orbit, SWOT is designed to precisely measure the fine differences in surface elevations around smaller currents and eddies, where much of the heat and carbon reduction from the oceans is thought to occur.
And SWOT can do it with 10 times greater resolution than existing technologies, according to JPL.
Searching for the turning point of the ocean
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 climate scientists answer a key question:
“What is the tipping point at which the oceans begin to release, rather than absorb, large amounts of heat into the atmosphere and accelerate global warming, rather than limit it,” said Nadya Vinogradova Shiffer , a NASA SWOT program scientist in Washington.
SWOT’s ability to discern smaller surface features will also be used to study the impact of rising ocean levels on coastlines.
More accurate data along intertidal zones would help predict how far stormwater flooding can penetrate inland, as well as the extent of saltwater intrusion into estuaries, wetlands and underground aquifers.
Freshwater bodies are another key SWOT focus, equipped to observe the entire length of almost all rivers over 100 meters wide, as well as over 1 million lakes and reservoirs over 62,500 square meters .
Taking an inventory of Earth’s water resources repeatedly 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 SWOT freshwater science manager, said that collecting this data is akin to “taking the pulse of the world’s water system, so we can see when it’s progressing and we’ll see when it’s slow.”
SWOT’s radar instrument operates in the so-called Ka-band frequency of the microwave spectrum, allowing scans to penetrate cloud cover and darkness across wide swaths of Earth.
This allows scientists to accurately map their observations in two dimensions, regardless of weather or time of day and cover large geographic areas much faster than before.
In comparison, previous studies of water bodies 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 by extrapolation.
“Instead of giving us an elevation line, it’s giving us an elevation map, and that’s just a total game changer,” Pavelsky said.
Reuters