UW glaciologist gets first look at NASA’s new measurements of ice sheet elevation

With each pass of the ICESat-2 satellite, the mission is adding to datasets tracking Earth’s rapidly changing ice.

The horizontal blue line is the travel path for ICESat-2. The lower line shows some of its first measurements. This satellite can capture steep terrain and measure elevation much more precisely than its predecessor.NASA's Earth Observatory/Joshua Stevens
The horizontal blue line is the travel path for ICESat-2. The lower line shows some of its first measurements. This satellite can capture steep terrain and measure elevation much more precisely than its predecessor.NASA's Earth Observatory/Joshua Stevens

ICESat-2 (short for Ice, Cloud, and land Elevation Satellite)- launched on Sept. 15, 2018, uses lasers and a very precise detection instrument to measure the elevation of Earth’s surface. Just a few months after the launch, the ICESat-2 is already exceeding scientists’ expectations.

The satellite is proficiently measuring the height of sea ice to within an inch, tracing the terrain of previously unmapped Antarctic valleys and measuring other interesting features in our planet’s elevation.

Benjamin Smith, a glaciologist with the University of Washington and member of the ICESat-2 science team said, “Mountain valleys have been really difficult targets for altimeters in the past, which have often used radar instead of lasers and they tend to show you just a big lump where the mountains are. But we can see very steeply sloping surfaces; we can see valley glaciers; we’ll be able to make out very small details.”

As the satellite is passing, the mission is adding to the data sets that track Earth‘s quickly evolving ice. Analysts are prepared to utilize the data to examine sea level rise coming about because of melting ice sheets and glaciers, and to enhance ocean ice and climate forecasts.

Smith said, “In topographic maps of the Transantarctic Mountains, which divide east and west Antarctica, there are places where other satellites cannot see. Some instruments don’t orbit that far south, while others only pick up large features or the highest points and so miss minor peaks and valleys. Since launching ICESat-2, in the past three months, scientists have started to fill in those details.”

“It’s spectacular terrain. We’re able to measure slopes that are steeper than 45 degrees, and maybe even more, all through this mountain range.”

“As ICESat-2 orbits over Antarctica, the photons reflect from the surface and show high ice plateaus, crevasses in the ice 65 feet (20 meters) deep, and the sharp edges of ice shelves dropping into the ocean. These first measurements can help fill in the gaps of Antarctic maps, but the key science of the ICESat-2 mission is yet to come. As researchers refine knowledge of where the instrument is pointing, they can start to measure the rise or fall of ice sheets and glaciers.”

“Very soon, we’ll have measurements that we can compare to older measurements of surface elevation. And after the satellite’s been up for a year, we’ll start to be able to watch the ice sheets change over the seasons.”

Mission managers expect to release the data to the public in early 2019.