Up until last winter, the thickness of Arctic sea ice showed a slow downward trend during the previous five winters, but after the summer 2007 record low extent, the thickness of the ice also nose-dived. What is concerning is that sea ice is not just receding but it is also thinning.
Some scientists blamed the record summer 2007 ice extent low on unusually warm weather conditions over the Arctic, but this summer, sea ice extent reached the second lowest level since records began, even though the Arctic had a relatively cool summer. Dr Katharine Giles, who led the study and is based at the Centre for Polar Observation and Modelling at University College London – part of the National Centre for Earth Observation, says: “This summer’s low ice extent doesn’t seem to have been driven by warm weather, so the question is, was last winter’s thinning behind it?”
The team of researchers, including Dr Seymour Laxon and Andy Ridout, used satellites to measure sea ice thickness over the Arctic from 2002 to 2008. Winter sea ice in the Arctic is around two and half metres thick on average. Ice thickness can be calculated from the time it takes a radar pulse to travel from a satellite to the surface of the ice and back again.
The research - reported in Geophysical Research Letters - showed that last winter the average thickness of sea ice over the whole Arctic fell by 26cm (10 per cent) compared with the average thickness of the previous five winters, but sea ice in the western Arctic lost around 49cm of thickness. This region of the Arctic saw the North-West passage become ice free and open to shipping for the first time in 30 years during the summer of 2007.
The team is the first to measure ice thickness throughout the Arctic winter, from October to March, over more than half of the Arctic, using the European Space Agency’s Envisat satellite. Before this, Christian Haas of the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, had discovered thinner ice in a small region around the North Pole. Whilst the overall loss of older, thicker ice led researchers to speculate that Arctic sea ice had probably thinned, this is the first time scientists have been able to say for definite that the ice thinning was widespread and occurred in areas of both young and old ice.
“The extent of sea ice in the Arctic is down to a number of factors, including warm weather melting it as well as currents and the wind blowing it around, so it’s important to know how ice thickness is changing as well as the extent of the ice,” added Giles.
The team will continue to monitor the thickness of the ice over this coming winter. Laxon says: “We’ll be keeping our eyes on the ice thickness this winter as it’ll be interesting to see what happens after a second summer of low ice extent.”
The Envisat satellite that provided the UCL scientists with their data doesn’t cover the whole of the North Pole. Because of the satellite’s orbit, there’s a hole north of 81.5 degrees, which is about 600 miles shy of the North Pole. But a team, including Laxon, at the Centre for Polar Observation and Modelling has designed a satellite – CryoSat-2 – to plug this hole.
CryoSat-2 is the first radar satellite specifically designed to measure ice thickness. It will do this with greater resolution than is possible with Envisat and so will give scientists a much more detailed picture of what is happening to ice in the Arctic. CryoSat-2 is being prepared for launch at the end of 2009.
Tamera Jones | alfa
Multi-year submarine-canyon study challenges textbook theories about turbidity currents
12.12.2017 | Monterey Bay Aquarium Research Institute
How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas
11.12.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
12.12.2017 | Physics and Astronomy
12.12.2017 | Earth Sciences
12.12.2017 | Power and Electrical Engineering