[ad_1]
->
A new study, published on April 30, 2020 in Science, used an advanced laser Earth observation instrument on board a satellite to make precise and detailed measurements of how the elevation of the Greenland and Antarctic ice sheets has changed between 2003 and 2019.
The study results show that small ice gains in East Antarctica are overshadowed by massive losses in West Antarctica. According to scientists, the net loss of Antarctic ice, coupled with the reduction of the Greenland ice sheet, has been responsible for 0.55 inches (14 millimeters) of sea level rise between 2003 and 2019, slightly less than a third of the total amount of sea. level increase observed in the world’s oceans.
The findings compared recent data from NASA’s Ice, Cloud, and Earth Elevation Satellite 2 (ICESat-2), launched in 2018, with measurements taken by the original ICESat from 2003 to 2009.
Using data from the ICESat and ICESat-2 laser altimeters, the scientists accurately measured the amount of ice lost from the ice sheets in Antarctica and Greenland between 2003 and 2019. The Antarctic Peninsula, seen here, was one of the fastest changing regions of the continent. . Image via NASA / K. Ramsayer
The study found that the Greenland Ice Sheet lost an average of 200 gigatons of ice per year, and the Antarctic Ice Sheet lost an average of 118 gigatons of ice per year.
How much ice is that? One gigaton of ice is enough to fill 400,000 Olympic pools or cover New York’s Central Park with ice over 1,000 feet (300 meters) thick, reaching higher than the Chrysler Building.
The new data comes from what NASA describes as its most advanced Earth observation laser instrument to have ever flown in space:
The ICESat-2 instrument is a laser altimeter, which sends 10,000 pulses of light per second to the Earth’s surface, and the time it takes to return to the satellite, within a billionth of a second. The pulse rate of the instrument allows a dense measurement map on the ice sheet; Its high precision allows scientists to determine how much an ice cap changes over a year to an inch.
The researchers tracked previous ICESat measurements and overlayed the tracks from the 2019 ICESat-2 measurements, and took data from the tens of millions of sites where the two data sets intersected. That gave them the elevation change, but to find out how much ice was lost, the researchers developed a new model to convert the change in volume to change in mass. The model calculated the densities across the ice sheets to allow calculation of the total mass loss.
Greenland. Image via NASA.
Ben Smith is a glaciologist at the University of Washington and lead author of the new article. Smith said in a statement:
If you watch a glacier or ice cap for a month or a year, you won’t learn much about what the weather is doing to you. We now have a 16-year period between ICESat and ICESat-2 and we can be much more confident that the changes we are seeing on the ice have to do with long-term changes in the climate.
Bottom line: The new maps made with satellite data show 16 years of ice sheet loss in Antarctica and Greenland.
Source: The massive loss of the widespread ice sheet reflects competitive processes of the ocean and the atmosphere.
Through NASA
