During the last two centuries the amount of ice discharge in the Greenland Sea has risen. ‘Ice discharge’ is a term describing a large piece of ice breaking off and drifting away from the existing ice sheet as an iceberg, or melting from the ocean at the calving terminus. When it leaves the ice cap and moves into fiords and coastal seas, the iceberg impacts a series of physical and biological systems and thereby plays a large part in the global sea level rise.
Therefore, glaciology and climate researchers from GEUS and DTU Space have studied the development of iceberg formation between 1986 and 2019.
When it comes to glaciers in Greenland, researchers often point to eight great discharge glaciers, which are pivotal when it comes to the massive loss of ice in Greenland. For this scientific project, the researchers studied the development of solid ice discharge from two of the glaciers, Sermeq Kujalleq, also known as the Jakobshavn Glacier, and the Helheim Glacier.
And they discovered a surprising new change in the order between the two glaciers.
The glaciers follow each other’s dynamics
What used to be true since the 1990s has changed. Until recently, Sermeq Kujalleq was the glacier in Greenland to have lost most ice in the shape of icebergs. But for the first four months of both 2019 and 2020, Sermeq Kujalleq loses fewer iceberg while Helheim loses more. This means that there is sometimes a new leader in the sad ‘melting race’.
“This shows that the system can change quickly,” says Ken Mankoff, senior researcher at GEUS and co-author of the new study, which has just been published in the scientific journal Earth System Science Data (ESSD).
More frequent updates on the development in Greenland
The science project is based on data from a new satellite constellation called Sentinel-1 owned by the European Space Agency (ESA). This satellite not only makes it possible for the researchers to update the data related to the development in Greenland more frequently, the quality of the data will be much better as well.
Anne Munch Solgaard, researcher at GEUS and part of the project, had the important job of analysing the satellite data that now give an insight into the development of iceberg formation.
”With the launch of ESA’s Sentinel-1-satellites it became possible to monitor the liquidity of the Greenland Ice Sheet in a high temporal resolution – all year round, even in the winter when it is dark. This offers huge potential to us as scientists because it makes it possible to calculate e.g. how much ice is leaving the Greenland Ice Sheet as icebergs, on an almost weekly basis, as we did in this study. This is unique knowledge, which enables us to investigate the dynamic of glaciers and the processes in even greater detail.”
Right now, researchers are able to update their results every 24 days, but their target is to delight the scientific community and everyone else interested with new data every 12 days so that the development in this cold part of the world will be described in even more detail.