Ice lost in Antarctica often makes headlines, but this is the first time scientists have deeply
Survey results show that glacierslost a total of 315 gigatons of ice, raising the global mean sea level by 0.9 mm, equivalent to 126 million Olympic swimming pools.
The Goetz region in Antarctica is so remote thatpeople have never set foot on most of it. But satellites showing high rates of glacier speed increase coupled with thinning ice now confirm that the Goetz Basin is in a dynamic imbalance, meaning it is losing more ice than it receives from snowfall.
Scientists have used two different types of satellitemeasurements. Radar data from the Copernicus Sentinel-1 mission, legacy data from the ERS mission from ESA's climate change initiative, and NASA data from MEaSUREs allowed them to calculate how fast glaciers moved over a 25-year study period. To measure how much the ice is thinning, they used altimetry data from ESA's ERS, Envisat and CryoSat missions through the IMBIE assessment.
"Using a combination of observations andsimulations, we show narrowly targeted acceleration models. For example, we see the biggest changes in the central Goetz region, where one glacier is flowing 391 meters per year faster in 2018 than in 1994. This is a significant change, as the flow rate is now 669 meters per year, an increase of 59% in just two and a half decades.”
Heather Selley, glaciologist at the Center for Polar Observations and Modeling at the University of Leeds
Widely reported thinning and accelerating,observed in adjacent glaciers in the Amundsen Sea, now extends 1,000 km along the West Antarctic coast to Getz. The glacier acceleration model shows a highly localized response to ocean dynamics.
But scientists need consistent and extensivesampling both ice velocity and ocean temperature to better understand dynamic ice loss, which currently accounts for 98.8% of Antarctica's contribution to sea level rise. By examining 25-year measurements of the ocean, the research team was able to show complex annual variations in ocean temperature. These results suggest that ocean warming is largely responsible for this dynamic imbalance.
“Without satellites, we know very little aboutremote polar regions, so it is important that we continue to plan missions for the future. For example, the future Biomass Earth Explorer satellite will be able to take measurements with an entirely new instrument that operates in the P-band to penetrate deep into ice. Other missions related to the polar regions include the Copernicus Expansion missions: CRISTAL, which will carry a dual-band altimeter, and ROSE-L, which will carry an L-band synthetic aperture radar."
Markus Engdahl, European Space Agency
This activity contributes to the efforts of PolarESA's science cluster to develop our ability to observe, understand and predict dramatic changes affecting the polar regions and subsequent impacts around the world.
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