Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tracking the amount of sea ice from the Greenland ice sheet

28.09.2016

By analysing ice cores drilled from deep inside the Greenland ice sheet, researchers have started to calculate how much Arctic sea ice there was in the past. Researchers from Denmark, Italy, Spain and Japan have just published the results in the research journal Scientific Reports.

The Greenland ice sheet records information about Arctic temperature and climate going back to more than 120 000 years ago. But new research reveals that the ice doesn’t just tell us about the situation in the air and on the land – it can also tell us about what was happening at sea.


Arctic sea ice max-min


Andrea Spolaor - Svalbard

By analysing ice cores drilled from deep inside the Greenland ice sheet, researchers have started to calculate how much Arctic sea ice there was in the past. Researchers from Denmark, Italy, Spain and Japan have just published the results in the research journal Scientific Reports.

Arctic sea ice is changing. In the past the Arctic Ocean was covered by metres of thick sea ice but now that sea ice is thinning and being replaced by sea ice that melts away over the summer. The rapid decrease of summer sea ice that we currently observe is opening up the region for shipping and exploration but also threatening local ecosystems and cultures. But what was sea ice like in the past?

The amount of sea ice has only been well known since the 1970’s when satellite measurements began, so we don’t know what has been happening far back into the past.

Researchers at the Niels Bohr Institute in Denmark and Ca’Foscari Univeristy of Venice in Italy have discovered that chemical traces of sea ice can be found far away from the ocean within the kilometres-thick Greenland ice sheet.

The ice sheet is covered by snow which falls every year and is compressed into ice over many thousands of years. Every layer of ice tells us about the year that the snow originally fell on the ice sheet – what the temperature was like and what kinds of particles were blowing around in the atmosphere at that time.

”We can measure the amount of a chemical called bromine in the Greenland ice cores. You find bromine in both the ocean and sea ice, but when new sea ice forms in the winter the sea salt is concentrated into salty pockets of brine which contain bromine. In spring and summer, the sunlight that shines down onto the sea ice starts chemical reactions.

In these reactions, ozone in the air reacts with bromine in the ice and the bromine is released in greater and greater amounts from the sea ice. This process is called a bromine explosion. When it is released from the sea ice, the concentrated bromine is carried by the wind up onto the ice sheet and then deposited with the falling snow. That is the source of the bromine we measure in ice cores”, explains Andrea Spolaor, researcher at Ca’ Foscari University of Venice, ”The reactions stop in autumn and winter, when the sun goes below the horizon and new sea ice begins to form again.”.

Reconstructing sea-ice in the past
It’s one thing to measure the amount of bromine in an ice core from Greenland, but it’s another thing to understand the connection between bromine and the amount of sea ice in the Arctic.

In order to link the bromine measurements with the amount of sea ice covering the Arctic, scientists have used satellite observations of sea ice as a measuring stick, which goes back to the 1970’s. The measurements can be used to link the bromine content in the ice cores with the amount of new sea ice produced each year since 1979. A clue about the amount of sea ice in the past has also been revealed by records from Icelandic fishing communities, which go back more than 1000 years. Altogether, these data have allowed researchers to calculate how much sea ice there was in the Arctic tens of thousands of years ago.

”With this technique we can fill the gaps in our understanding of the amount of Arctic sea ice in the past. Since ice cores also reveal a lot of information about the climate, we can combine the sea ice data with the climate data and start to understand how sea ice reacts to climate change” explains Paul Vallelonga, Associate Professor at the Centre for Ice and Climate at the Niels Bohr Insitute, University of Copenhagen.

Sea ice and climate change
Researchers have found that 8000 years ago the Arctic climate was 2 to 3 degrees warmer than now, and that there was also less summertime Arctic sea ice than today.

”We have been in this situation before, with less sea ice and more open ocean during the warm Arctic summer. So right now we have not yet exceeded the natural boundaries for the Arctic region, but the question is: with more warming in the Arctic driven by rising greenhouse gases, how soon will sea ice melting reach and exceed the levels of 8000 years ago? These new research results can help us to answer this question when we combine them with climate models”, says Paul Vallelonga.

http://www.nature.com/articles/srep33925 

For further information, please contact:

Andrea Spolaor

Ca’ Foscari University of Venice

+39 3337464504

andrea.spolaor@unive.it

Andrea Spolaor | AlphaGalileo
Further information:
http://www.unive.it

Further reports about: Arctic sea ice Greenland ice sheet bromine ice cores ice sheet

More articles from Earth Sciences:

nachricht Six-decade-old space mystery solved with shoebox-sized satellite called a CubeSat
15.12.2017 | National Science Foundation

nachricht NSF-funded researchers find that ice sheet is dynamic and has repeatedly grown and shrunk
15.12.2017 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

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...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

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,...

Im Focus: Towards data storage at the single molecule level

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>