Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How do they do it? Predictions are in for Arctic sea ice low point

15.08.2012
It's become a sport of sorts, predicting the low point of Arctic sea ice each year. Expert scientists with decades of experience do it but so do enthusiasts, whose guesses are gamely included in a monthly predictions roundup collected by Sea Ice Outlook, an effort supported by the U.S. government.

When averaged, the predictions have come in remarkably close to the mark in the past two years. But the low and high predictions are off by hundreds of thousands of square kilometers.

Researchers are working hard to improve their ability to more accurately predict how much Arctic sea ice will remain at the end of summer. It's an important exercise because knowing why sea ice declines could help scientists better understand climate change and how sea ice is evolving.

This year, researchers from the University of Washington's Polar Science Center are the first to include new NASA sea ice thickness data collected by airplane in a prediction.

They expect 4.4 million square kilometers of remaining ice (about 1.7 million square miles), just barely more than the 4.3 million kilometers in 2007, the lowest year on record for Arctic sea ice. The median of 23 predictions collected by the Sea Ice Outlook and released on Aug. 13 is 4.3 million.

"One drawback to making predictions is historically we've had very little information about the thickness of the ice in the current year," said Ron Lindsay, a climatologist at the Polar Science Center, a department in the UW's Applied Physics Laboratory.

To make their prediction, Lindsay and Jinlun Zhang, an oceanographer in the Polar Science Center, start with a widely used model pioneered by Zhang and known as the Pan-Arctic Ice Ocean Modeling and Assimilation System. That system combines available observations with a model to track sea ice volume, which includes both ice thickness and extent.

But obtaining observations about current-year ice thickness in order to build their short-term prediction is tough. NASA is currently in the process of designing a new satellite that will replace one that used to deliver ice thickness data but has since failed. In the meantime, NASA is running a program called Operation IceBridge that uses airplanes to survey sea ice as well as Arctic ice sheets.

"This is the first year they made a concerted effort to get the data from the aircraft, process it and get it into hands of scientists in a timely manner," Lindsay said. "In the past, we've gotten data from submarines, moorings or satellites but none of that data was available in a timely manner. It took months or even years."

There's a shortcoming to the IceBridge data, however: It's only available through March. The radar used to measure snow depth on the surface of the ice, an important element in the observation system, has trouble accurately gauging the depth once it has melted and so the data is only collected through the early spring before the thaw.

The UW scientists have developed a method for informing their prediction that is starting to be used by others. Researchers have struggled with how best to forecast the weather in the Arctic, which affects ice melt and distribution.

"Jinlun came up with the idea of using the last seven summers. Because the climate is changing so fast, only the recent summers are probably relevant," Lindsay said.

The result is seven different possibilities of what might happen. "The average of those is our best guess," Lindsay said.

Despite the progress in making predictions, the researchers say their abilities to foretell the future will always be limited. Because they can't forecast the weather very far in advance and because the ice is strongly affected by winds, they have little confidence beyond what the long-term trend tells us in predictions that are made far in advance.

"The accuracy of our prediction really depends on time," Zhang said. "Our June 1 prediction for the Sept. 15 low point has high uncertainty but as we approach the end of June or July, the uncertainty goes down and the accuracy goes up."

In hindsight, that's true historically for the average predictions collected by Study of Environmental Arctic Change's Sea Ice Outlook, a project funded by the National Science Foundation and the National Oceanic and Atmospheric Administration.

While the competitive aspect of the predictions is fun, the researchers aren't in it to win it.

"Essentially it's not for prediction but for understanding," Zhang said. "We do it to improve our understanding of sea ice processes, in terms of how dynamic processes affect the seasonal evolution of sea ice."

That may not be entirely the same for the enthusiasts who contribute a prediction. One climate blog polls readers in the summer for their best estimate of the sea ice low point. It's included among the predictions collected by the Sea Ice Outlook, with an asterisk noting it as a "public outlook."

The National Science Foundation and NASA funds the UW research into the Arctic sea ice low point.

For more information, contact Lindsay at lindsay@apl.washington.edu or 206-543-5409 Zhang at zhang@apl.washington.edu or 206-543-5569

Nancy Gohring | EurekAlert!
Further information:
http://www.uw.edu

More articles from Earth Sciences:

nachricht Stagnation in the South Pacific Explains Natural CO2 Fluctuations
23.02.2018 | Carl von Ossietzky-Universität Oldenburg

nachricht First evidence of surprising ocean warming around Galápagos corals
22.02.2018 | University of Arizona

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>