Shelf ice, as found in Antarctica, refers to giant floating ice sheets that can span thousands of square kilometres. Pieces break off at their edges which form icebergs in the ocean. In order to more effectively predict these break-offs, in a process known as calving, Julia Christmann from the University of Kaiserslautern (TU) has developed mathematical models in cooperation with the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). On the basis of physical factors, it is claimed that these models can be used to predict when and where the ice may collapse. This is important particularly for research teams situated on the ice shelf.
The ice rises up like a sheer cliff face – shelf ice is not only several thousand square kilometres large, it is also more than a hundred metres high in many places. From time to time, pieces break off the edge and crash into the sea below, where they float away in the ocean as icebergs. This was also recently the case with the Larsen C ice shelf.
Julia Christmann in front of the icebreakter "Polarstern" in the Antarctica
Credit: Julia Christmann
Science is unable to accurately predict when and where the ice shelf will break. “Assumptions were always previously based on observations by glaciologists and other researchers. Concrete calculations with physical parameters did not exist,” says Julia Christmann, who is researching technical mechanics at the University of Kaiserslautern with Professor Dr Ralf Müller. As a rule of thumb, she explains, the ice tends to break where it is thinner than 200 metres; in reality, however, there are also many ice shelves that are even thinner.
The calving of ice sheets is a continuous process that is influenced by a number of different factors. Satellite data was also used in order to observe this natural spectacle. “However, they only offer snapshots of the process,” Christmann adds. As part of her doctorate research, she has developed mathematical models to calculate when and where the ice shelf may collapse. A range of different physical factors are germane here.
“The thickness and density of ice can play an important role, for example,” Christmann continues. “The material parameters are also critical, including elastic factors. These mainly influence where the iceberg is calved. There is also the viscosity, which affects the time between break-off events.”
The doctoral student at Kaiserslautern was also supported in her work by Professor Dr Angelika Humbert from the AWI. Humbert is an expert in the field of glaciology. She is also occupied with the properties and motion of giant ice sheets on the Antarctic continent, which constitute 70 percent of the entire supply of freshwater on the planet.
“The ice shelf generally breaks at points that are between a half and full thickness of the ice sheet from the edge,” summarises Christmann. This data may be particularly important for the scientific community, since numerous research stations are located on ice shelves in Antarctica. This includes the German Neumayer Station III or the British station, Halley VI, which was closed for winter this year due to a crack in the ice.
Christmann recently completed her doctoral thesis. She is continuing her research on the properties of ice. She is now focusing on grounding lines in Greenland. This refers to the area in which the ice still touches the ground and merges into floating shelf ice. The researcher intends to find out how these lines change over the course of time.
Dr Julia Christmann
Tel.: 0631 205-2126
Melanie Löw | Technische Universität Kaiserslautern
Turbulence creates ice in clouds
08.11.2019 | Leibniz-Institut für Troposphärenforschung e. V.
Manganese nodules: project on environmental impact during deep sea mining
08.11.2019 | Jacobs University Bremen gGmbH
If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.
Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...
Quantum-based communication and computation technologies promise unprecedented applications, such as unconditionally secure communications, ultra-precise...
In two experiments performed at the free-electron laser FLASH in Hamburg a cooperation led by physicists from the Heidelberg Max Planck Institute for Nuclear physics (MPIK) demonstrated strongly-driven nonlinear interaction of ultrashort extreme-ultraviolet (XUV) laser pulses with atoms and ions. The powerful excitation of an electron pair in helium was found to compete with the ultrafast decay, which temporarily may even lead to population inversion. Resonant transitions in doubly charged neon ions were shifted in energy, and observed by XUV-XUV pump-probe transient absorption spectroscopy.
An international team led by physicists from the MPIK reports on new results for efficient two-electron excitations in helium driven by strong and ultrashort...
An international research group has observed new quantum properties on an artificial giant atom and has now published its results in the high-ranking journal Nature Physics. The quantum system under investigation apparently has a memory - a new finding that could be used to build a quantum computer.
The research group, consisting of German, Swedish and Indian scientists, has investigated an artificial quantum system and found new properties.
Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory have reported a new mechanism to speed up the charging of lithium-ion...
05.11.2019 | Event News
30.10.2019 | Event News
02.10.2019 | Event News
12.11.2019 | Machine Engineering
12.11.2019 | Power and Electrical Engineering
12.11.2019 | Physics and Astronomy