ICESat-2 helps scientists measure ice thickness in the Weddell Sea

Dec. 18 (UPI) -- Measurements by NASA's Ice, Cloud and land Elevation Satellite-2 are helping scientists map ice thickness across the Southern Ocean's Weddell Sea.

By mapping and tracking changes in the thickness of sea ice surrounding Antarctica, scientists hope to pinpoint when and where seasonal sea ice first grows.

"We know a lot less about the sea ice in the Antarctic than the Arctic," Ron Kwok, sea ice scientist at NASA's Jet Propulsion Laboratory, said in a news release.

ICESat-2, which launched in September, uses six speedy lasers to measure the height of Earth's surface with extreme precision. The measurements can help scientists determine the thickness of sea ice surrounding the planet's poles.

"We can see so much more detail than we have seen before," Kwok said.

The detail made visible by ICESat-2's Advanced Topographic Laser Altimeter System is on display in a new image shared this week by NASA's Earth Observatory. The image features elevation measurements made by ATLAS. The data points follow the orbital path traced across the Weddell Sea by ICESat-2 on October 17, 2018.

As ICESat-2 moved north, or left, across the Weddell Sea, its ATLAS instrument measured thinner and thinner ice thickness. Photo by ICESat-2/NASA/Earth Observatory

Scientists at NASA's Earth Observatory overlaid the data chart atop a satellite image of the Weddell Sea to show exactly where ICESat-2 measured the height of the sea ice.

ATLAS's six lasers fire nearly 10,000 shots per second, and the instrument can measure to within a billionth of a second how long it takes a single photon to travel to Earth's surface and back.

As revealed by the diagram and underlying image, ATLAS measured thinner and thinner ice as ICESat-2 moved north toward the edge of the ice cover. Scientists can determine ice thickness by comparing the height difference between ice and adjacent open ocean. The ice above sea surface typically represents one-tenth of the ice's total thickness -- the other nine-tenths are underwater.

More accurate sea ice data will help scientists design more accurate climate models, as well as help researchers better understand the impacts of climate change on Earth's poles.