Jenam 2011Illustration of NASA’s Ice, Cloud and land Elevation Satellite-2 (ICESat-2), a mission to measure changes in the height of Earth’s ice. Credit: NASA
Melting ponds, summer ice and more: Space laser measurements are changing the Earth
Since 2003, the Arctic sea ice has lost about a third of its volume. On the other side of the world, at the other pole, new glacial lakes have been discovered deep below the surface of the Antarctic ice. And at intermediate latitudes, changing water levels in reservoirs have revealed human influences.
These are just some of the more than 100 new discoveries made with precise height data from the 12 trillion laser measurements collected from
Since its launch in September 2018, ICESat-2 has collected data and inspired research on our changing Earth – from ice to tropical beaches and from boreal forests to urban areas. Before launch, members of the mission science team talked about what they hoped would help us understand. After successfully completing its three-year primary mission, the mission now has the green light to continue operations, and these ice experts are sharing what they’ve discovered.
ICESat-2 measurements offer an incredible level of accuracy as it measures the Earth’s surface, including the Antarctic Ice Sheet seen here. Credit: NASA Goddard Space Flight Center / Kate Ramsayer
Ice and beyond
Alex Gardner, NASA’s Jet Propulsion Laboratory in Southern California
“I am truly amazed at the engineering of ICESat-2. We count individual photons bouncing off the Earth’s surface – with incredible precision. And the science behind it is incredible. Right away we saw changes in the Antarctic and Greenland ice sheets, the influence of the ocean eating away at the ice and melting the surface in Greenland.
“But what also really stood out was the diversity of scientific fields using ICESat-2. It covers ocean science, hydrology, cryosphere, biosphere – I knew there would be many ways to use the data, but I don’t think I anticipated how quickly it would happen. I look forward to the tsunami of studies to come.
A glacier on the Antarctic Peninsula flows into the Bellingshausen Sea, seen from a flight of the Operation IceBridge airborne mission, used to calibrate and validate ICESat-2 data. Credit: NASA/Kate Ramsayer
Melt in Antarctica
Brooke Medley, NASA Goddard Space Flight Center in Greenbelt, Maryland
“I think one of the coolest things we’ve seen are melt pools in Antarctica. It works your brain – if we could automatically detect individual ponds and measure their depth, that could tell us about the storage of liquid water on the surface of the ice sheet, which is one of the most difficult things to estimate on this large scale.
“It’s a good thing about ICESat-2 – the scales at which you can observe processes range from very small, like blowing snow, to the entire ice sheet.”
summer ice cream
Nathan Kurtz, NASA Goddard
“Over the past few decades, the Arctic sea ice that lasted all summer has not survived. And ICESat-2 works surprisingly well in the summer, given the clouds and melt pools. So we can track the thickness of sea ice during the melt season and determine more precisely what is causing the melt.
“A lot of people are interested in sea ice forecasts and wondering if, over the course of a summer, the Arctic will be essentially free of sea ice. ICESat-2 helps us say with confidence what is happening .
Accuracy and precision from the start
Kelly Brunt, NASA Goddard and the National Science Foundation
“ICESat-2 was accurate and precise right from the start. Coupled with that, he has excellent pointing knowledge and excellent pointing control, meaning we aim to get to a point and we get it.
“So when we repeat orbits to measure how things change over time, we can get a better idea of things like the anchorage zone of ice shelves, where the ice meets the ocean. We can better measure where they are and also see the impact of the tides on the floating ice.
A gap in the sea ice cover north of Greenland is partially filled by much smaller rubble and sea ice floes, as seen during an Operation IceBridge flight in September 2019. Credit: NASA/Linette Boisvert
Snow on ice on water
Ron Kwok, University of Washington
“ICESat-2 is a fantastic instrument, as we have a significant improvement in resolution. He lets us see these narrow channels, the open water between the ice floes.
“Equally important, we can now pair it with CryoSat-2 to measure snow depth. ICESat-2 measures the top of the snow, CryoSat-2 detects the interface of snow and ice, and together the data tells us not only the depth of the snow, but also the thickness of the sea ice. After three years of ICESat-2 winter measurements, we saw the changes in the ice – and those changes were not insignificant.
Frozen flood ponds on pack ice, seen during an Operation IceBridge flight in March 2017. Credit: NASA/Jeremy Harbeck
A new level of detail
Sinead Farrell, University of Maryland, College Park
“The level of detail we can get with ICESat-2 is something we have never achieved with any other satellite. It’s a game changer.
“It gives us information about melt ponds on sea ice, which are roughly the size of Olympic swimming pools – and ICESat-2 can measure their depth from space. This is huge because it allows us to understand how multi-year ice melts in summer. We need to observe melt pools to understand how vulnerable the ice is to further loss.
Detect climate impacts
Thorsten Markus, NASA Washington Headquarters
“ICESat-2 went beyond what it was designed to do. I’m looking forward to extending the time series to get monthly data for polar regions over the years – something we haven’t had.
“As we go into five, six, seven years of data, we can actually see climate signals beyond what is due to weather. Then it gets really interesting and we can better understand the impact of the climate at the poles.
