ICESat-2 satellite reveals the shape and depth of cracks in Antarctica's ice shelves

Ice calving, also known as glacier calving or iceberg calving, is the separation of chunks of ice fromthe edges of the glacier,

In other words, ice calving is the sudden release and separation of a mass of ice from itsglacier, iceberg, ice front, ice shelf or crevasse.

Ice shelves make up almost 75% of the coastallines of Antarctica. They hold back the larger glaciers on land. If the ice shelves collapse and the Antarctic glaciers fall or melt into the ocean, the sea level will rise by 60 meters.

When scientists try to predict future contributionsAntarctica in sea level rise, the most uncertain factor in modeling is the stability of the ice shelf. Today there is no easy way to map the depth of glacier cracks on a regional scale. However, scientists have found that satellite data can capture the depth and morphology of the surface of the ice shelf's cracks and thus allow this information to be continuously monitored over a wide range.

Scientists have studied the high-resolution data,collected by the ICESat-2 satellite over the Amery Ice Shelf between October 2018 and November 2019. Laser pulses from a satellite are directed towards the surface of the Earth and use reflected photons to determine the height of the surface. Unlike other satellites, ICESat-2 resolution allows it to see finer fractures and their morphology.

Scientists processed satellite data usingalgorithm. It identifies surface ice depressions to locate and characterize fractures. Let us recall that the depression of the snow line is its decrease due to climatic changes favorable for maintaining the balance of the mass of glaciers. Since mass balance is a direct function of accumulation and ablation, fluctuations in the height of the snow line reflect the cumulative effects of changes in temperature and precipitation.

The research results are published in the journal Remote Sensing of Environment.

Researchers have identified three types of fractures:U-shaped; parabolic and V-shaped, up to 40 meters deep in the ice shelf. They also realized that surface information gives an idea of ​​what is happening hundreds of meters below the surface of the ice.

Basal fissure morphology - the shape and size of fissures at the base of an ice shelf - is proportional to depressions on the surface.

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