SWOT could turn out to be a significant improvement over previous satellite measurements. “Instead of a ‘pencil beam’ moving across the surface of the earth from a satellite, it’s a wide swath. It will provide much more information, much higher spatial resolution, and hopefully better coverage near shore,” says Steve Nerem, a University of Colorado scientist who uses satellite data to study sea level rise and is not involved with STREBER. And Karin’s swath mapping technology is brand new, he says. “It’s never been tested from orbit before, so it’s kind of an experiment. We are excited about the data.”
SWOT also has other instruments in its toolkit, including a radar altimeter to fill in the gaps between the plumes of data that KaRIn collects, a microwave radiometer to measure the amount of water vapor between SWOT and the Earth’s surface, and a set of mirrors for laser – Tracking measurements from the ground.
New satellite data is important because the future of sea level rise, flooding and drought could be worse than some experts have previously predicted. “In our satellite record, we have seen rapid sea level rise along US coasts over the past three decades,” says Ben Hamlington, a sea level rise scientist at JPL on the SWOT science team. In fact, sea level rise is accelerating, particularly on the Gulf Coast and East Coast of the United States. “The path we’re on points us toward the high end of the model projections,” he says, a point he made in a study published in Communications Earth & Environment last month.
Hamlington sees SWOT as a boon for mapping rising seawater and for researchers studying ocean currents and eddies that affect how much atmospheric heat and carbon oceans absorb. The satellite will also help scientists model storm surges — that is, when seawater flows onto land.
The data from the new spacecraft will have some synergy with many other Earth observation satellites already in orbit. These include NASA’s Grace-FO, which studies subsurface water using variations in gravity, NASA’s IceSat-2, which studies ice sheets, glaciers and sea ice, and commercial flood-mapping satellites that use synthetic aperture radar to see through clouds. It also follows other altimeter-equipped satellites, such as the US-European Jason-3, the European Space Agency’s Michael Freilich satellite Sentinel-6, China’s Haiyang satellites and the Indo-French Saral spacecraft.
Data from these satellites has already shown that some sea level rise, extreme flooding, storms and droughts are already etched into our future. But we are not doomed to climate catastrophe, Hamlington argues, because we can use this data to stave off the most extreme projected outcomes, such as those causing rapid melting of glaciers or ice sheets. “Reducing emissions takes some of the higher projections of sea level rise off the table,” he says. “Since catastrophic ice sheet loss will only occur in very warm future times, if we can limit future warming, we can avoid worst-case scenarios.”