New Delhi: Seems NASA scientists are not surprised by the rapid loss of ice in the Arctic Ocean this season.
In fact, they're calling the low levels the 'new normal' - that's because they're now used to these low levels of sea ice.
“A decade ago, this year’s sea ice extent would have set a new record low and by a fair amount. Now, we’re kind of used to these low levels of sea ice – it’s the new normal,” said Walt Meier, a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“Even when it’s likely that we won’t have a record low, the sea ice is not showing any kind of recovery. It’s still in a continued decline over the long term,” said Meier.
“It’s just not going to be as extreme as other years because the weather conditions in the Arctic were not as extreme as in other years.”
This year, NASA recorded a record low maximum extent for ice in the Arctic in March, and it lost a lot more ice throughout May.
The melt slowed down in June, but scientists say the rate of ice loss picked up again during the first two weeks of August, and is now greater than average for this time of the year.
Video credit: NASA.gov Video
Even as scientists are keeping an eye on the Arctic sea ice cover, NASA is also preparing for a new method to measure the thickness of sea ice - a difficult but key characteristic to track from orbit.
Research vessels or submarines can measure ice thickness directly, and some airborne instruments have taken readings that can be used to calculate thickness. However, according to Thorsten Markus, Goddard’s cryosphere lab chief, satellites haven’t been able to provide a complete look at sea ice thickness in particular during melting conditions.
The Ice, Cloud and land Elevation Satellite-2, or ICESat-2, which is slated to launch by 2018, will use lasers to try to get more complete answers of sea ice thickness.
Markus said in order to estimate the entire thickness of the ice floe, researchers will need to go beyond the above-water height measurements, and perform calculations to account for factors like the snow on top of the ice and the densities of the frozen layers.
"If we want to estimate mass changes of sea ice, or increased melting, we need the sea ice thickness. It’s critically important to understanding the changes in the Arctic," added Markus.