Stunning simulations reveal the shock waves that cause chunks of ice to calve
New computer simulations reveal the shock wave created when a chunk of ice breaks off a glacier. This shock wave causes sea ice to shift and can even spur ‘widespread fracture,’ increasing the chances of subsequent breakage events. Understanding these processes could help scientists to better predict how melting ice will contribute to sea-level rise.
The new study from California Institute of Technology examined the effect of the ‘melange’ breakup on iceberg calving – or the process of shedding chunks of ice.
Melange is a ‘floating aggregation of sea ice and icebergs,’ and scientists have long speculated that it may apply enough force on a glacier’s terminus to suppress calving.
In the winter, the icebergs that make up the melange freeze together, creating a ‘frozen iceberg logjam’ that prevents more material from breaking off.
But, as the weather gets warmer, the sea ice begins to thin, eventually allowing for the first calving event in the summer.
The new animation from Caltech reveals the effect of this process.
‘I developed a computer model that stimulates how the first iceberg calving of the warm season creates a shock wave that travels through the jammed melange, breaking it up,’ says Alexander Robel, a National Oceanic and Atmospheric Administration Postdoctoral Scholar and Stanback Postdoctoral Scholar at Caltech.
The simulations are made to resemble the fjords in Greenland.
As the weather gets warmer, the sea ice begins to thin, eventually allowing for the first calving event in the summer. The animation shows how melange responds to pressure applied by the movement of a glacier
These are narrow channels of water prone to trapping melange.
Not only does the spring sea-ice breakup rely on the thickness of the ice in within the melange, but the simulations revealed the shape of the channel plays a role as well.
When the first calving event happens, it sends a shock wave through the cluster of ice.
At first, it causes compression, which later leads to slow expansion.
As a result, the event can initiate widespread breakage of the sea ice.
