Over 24 years of radar data shows acceleration of ice loss in the Antarctic Peninsula
The acceleration of ice loss of 30 ice glaciers in the southwest Antarctic Peninsula is shown in observations made by five radar satellites during over two decades. Polar regions prone to bad weather and log periods of darkness can best be monitored by radar as they can collect information regardless of day, night, or clouds.
Over 24 years of radar data from satellites including ESA’s Envisat and ERS missions, as well as from the Copernicus Sentinel-1 mission are combined in a recent study published in Geophysical Research Letters. The team behind the study found that between 1992 and 2016, most of the 30 glaciers mapped sped up by 20 and 30 cm per day. This is equivalent to an average 13% increase in flow speed across the area as a whole.
In order to fill in gaps where no satellite data were available, the team combined the observations with an ice-flow model and this allowed the researchers to estimate that the glaciers’ speed increase has led to the discharge of 15 cubic km of ice per year into the surrounding ocean.
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“This new research – which is the first to map the actual change in ice speed – deviates from the previous interpretation, because the glacier speedup is in fact far too small,” Anna Hogg, lead author and researcher at the UK Centre for Polar Observation and Modelling, said.
According to a press release, the greatest acceleration in flow was observed at glaciers that were grounded at depths more than 300 m below the ocean surface.
“We looked at water temperatures in front of the glaciers which have sped up the most, and we found that they flow through deep bedrock channels into the warmest layer of the ocean. This circumpolar deep water, which is relatively warm and salty compared to other parts of the Southern Ocean, has warmed and shoaled in recent decades, and can melt ice at the base of glaciers which reduces friction and allows them to flow more freely,” Dr Hogg explained.
With much of Western Palmer Land’s ice mass lying well below sea level it is important to monitor how remote areas such as this are responding to further warming in the region due to climate change.
The two-satellite Sentinel-1 mission for Europe’s Copernicus programme routinely monitors polar areas at a high resolution, continuing the long-term data record from European satellites.
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