Over the next two weeks, a handful of NASA scientists will live very different lives than the rest of us: They will board a research plane in Greenland to help calibrate NASA's space measurements of Arctic ice together with laser instruments.
Ice researchers and instrument scientists will board NASA's Gulfstream V jet and fly out of Tulle Air Force Base in northwest Greenland for further north. If they were lucky with the weather, they would do it as many as seven times.
Air Sports will study the Arctic Ocean's ice, snow and meltwater pools during the warmer summer months to better understand melting sea ice.
Nathan Kurtz, an associate project scientist at ICESat-2 at NASA's Goddard Space Flight Center in Greenbelt, said: "The change in the thickness of arctic sea ice in the summer is very important because this is when thicker, multi-year ice is disappearing. " , Maryland." We wanted to track it, but historically, it was difficult to do it throughout the Arctic. ”
Ice scientists Nathan Kurtz (left), Rachel Tilling and Marco Bagnardi at NASA's Goddard Space Flight Center are conducting iceSat-2 aerial exercises in northwest Greenland to better understand how Arctic sea ice thickness changes during summer warming.
Credits: NASA/K. Ramsail
For sea ice thickness, satellite radar and laser measurements generally work well — during the three-quarters season. But in the summer, the open ocean on the ice and melting ponds make it trickier to accurately determine the height of the ice floating above the water.
Satellites have been tracking areas of sea ice covering the Arctic Ocean for more than four decades. Seasonal and year-on-year variations in this range show a significant downward trend: sea ice ranges over the past 15 summers have also reached their lowest values since records began in 1978.
Scientists believe that NASA's satellite ICESat-2, launched in September 2018, could effectively infer the thickness of this summer. IceSat-2 comes with an extremely accurate laser altimeter that collects a dense measurement grid that scientists use to measure the surface height of summer ice, melting ponds and water.
But to be sure, satellite measurements need to be confirmed by other measurements closer to the surface — which is why scientists have flown over some of the most remote areas on Earth.
The plane will fly at altitudes of 30,000 and 1,600 feet, and its course is designed to measure the same layer of ice covered by satellites orbiting about 300 miles above Earth. Two different laser instruments, one from Goddard and one from the University of Texas at Austin.
Aerial activity will examine ICESat-2 sea ice thickness estimates during the summer and improve their accuracy. These results will then be used to improve computer programs that provide information on ice thickness throughout the year.
Rachel Tilling, a Goddard sea ice scientist involved in the campaign, said that with the data from these instruments, scientists can improve the interpretation of summer ICESat-2 measurements. Tilling and her colleagues will use the data to see if surface water indicates a rupture between melting ponds or ice streams. It will give scientists a better idea of when and where the previously thick sea ice that has accumulated over the years thins.
This new information about the thickness of sea ice, combined with existing information about the extent of the ocean covered by ice, allowed the researchers to calculate changes in ice levels throughout the summer.
"Summer is when we see the most drastic changes in the range of sea ice, but we don't know what's going on beneath the surface," Tilling said. "We can assume that this also means that the volume is decreasing – but we actually need ICESat-2 thickness data to understand what drives the year-on-year change in summer sea ice volume."
Banner image: Arctic sea ice floats in the Walstenholm Fjord in northwestern Greenland in July 2022. A new ICESat-2 airborne campaign will use instruments on NASA's Gulfstream V jets to improve satellite measurements of sea ice melt. Credits: NASA/K. Ramsail