This bar chart shows how almost all of Earth’s water is saline and is found in the oceans. Of the small amount that is actually freshwater, only a relatively small portion is available to sustain human, plant and animal life. USGS/Igor Shiklamonov
One reason SWOT is important is that water covers so much of Earth’s surface — 71 percent, according to the U.S. Geological Survey (USGS). About 96.5 percent of the planet’s H2O is contained in the oceans. The remaining water is in rivers, lakes, icecaps and glaciers, and in the ground as soil moisture and aquifers.
But that water never really sits still in one place, due to the water cycle, in which water constantly moves from one place to another and switches forms. But global warming and climate change also are impacting the water cycle.
“[Climate change] has a huge impact today … on the water cycle, accelerating the water cycle by putting some drought in some parts of the world and floods in other parts,” said Selma CherchaliEarth observation program head at CNES. But until now, scientists have been stymied by the limitations of their knowledge due to insufficient data.
The new satellite will give scientists a look at that supply and demand chain in order for them to study Earth’s water as a complete process.
It won’t be just NASA and CNES scientists who’ll be using SWOT data. Researchers from 17 different countries are involved in the project, and eventually the data will be made accessible to anyone in the public who wants to analyze it.
Nadya Vinogradova ShifferSWOT program scientist at NASA, described monitoring and predicting the movement of water across the planet as a worthy investment.
“We as humanity depend on Earth water to survive and prosper,” Shiffer said. “We know that oceans are the ultimate source of all moisture and water on Earth. Think of oceans as huge warehouses that supply moisture and water to lands that we rely on for our drinking water, agriculture and industry.”
Knowing how much water is on Earth in various places also can help efforts to cope with water shortages in some places and rising seas and vanishing shorelines in others. SWOT data might help scientists to spot those patterns in advance, based on the supply wherever the water originates.
“The breakthrough is that we’re going to look at Earth water with a very high resolution and clarity, like never before,” Shiffer said. She said the images would be 10 times as detailed and clear as previous satellite images.
