Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists zero in on Arctic, hemisphere-wide climate swings

30.08.2002


In the late 1990s, as scientists were reaching consensus that the Arctic had gone through 30 years of significant climate change, they began reading the first published papers about the Arctic Oscillation, a phenomenon reported to have hemisphere-wide effects.



In short order the arctic-science and the global-change communities were galvanized, says Richard Moritz, polar oceanographer with the UW’s Applied Physics Laboratory and lead author of a review of recent Arctic climate change in the Aug. 30 special polar-science issue of Science.

"We’ve learned more about the dynamics of post-glacial arctic climate change in the last five years than in the 50 years previous," Moritz says. "For example, the recent trend in the Arctic Oscillation explains the warming observed in the Arctic better than anything else."


Advances in understanding arctic climate change are particularly timely, with some studies indicating that the recent trend in the Arctic Oscillation results partly from human activities that generate greenhouse gases and sulfate particles, and deplete stratospheric ozone. Scientists, planners and policymakers need to know what the changes of the last 30 years portend.

Thus climate modelers have redoubled their efforts to determine the physics behind the patterns of change. Although their models portray realistic day-to-day and month-to-month variations in the Arctic Oscillation, they fail to capture the magnitude of the longer term trend in the Arctic Oscillation that was observed from 1970 to 2000. While paleoclimatologists studying the climate record of the past 1,000 years have not reached a consensus on the importance of the Arctic Oscillation pattern over this longer period, some surprising findings indicate that past Arctic warmings tended to coincide with low-frequency El Nino-Southern Oscillation events in the tropical Pacific.

The review by Moritz and co-authors Cecilia Bitz, a sea-ice expert with the UW’s Applied Physics Laboratory, and Eric Steig, assistant professor with the UW’s Quaternary Research Center, refers to more than 80 published papers, most appearing in just the last two years. The co-authors say that warming of the surface from 1970 to 2000 in the Northern Hemisphere was greatest in the Arctic, causing changes in precipitation, snow cover and the extent of sea ice.

The Arctic Oscillation is a seesaw pattern in which atmospheric pressure at the polar and middle latitudes fluctuates between positive and negative phases. The wind patterns associated with the Arctic Oscillation affect the surface temperature over North America and Eurasia, as well as the Arctic. The Arctic Oscillation was first described in a 1998 article by David Thompson, then a graduate student at the UW and now an assistant professor at Colorado State University, and John M. Wallace, a UW professor.

"The Arctic Oscillation provides a very fruitful framework and the result is that a tremendous amount of work has been done in a relatively short period of time," Moritz says. "Attempts to model the pattern of recent Arctic and global warming have to come to grips with the problem of the Arctic Oscillation." Climate modelers have benefited from a growing understanding of sea-ice physics and the best-ever measurements of how heat from the sun and the atmosphere affects the pack ice that covers the Arctic Ocean. Moritz, for example, is director of the SHEBA (Surface Heat Budget of the Arctic Ocean) Project Office funded by the National Science foundation and Office of Naval Research. Now in its analysis phase, SHEBA locked an icebreaker into the pack ice for a full year in the late ’90s to measure the interactions of the ice, atmosphere and the ocean during all four seasons.

Because so many climate modelers worldwide are working on the Arctic Oscillation, Moritz says it’s conceivable that in a year or two we will understand the fundamental physics of the Arctic Oscillation, and be able to account for its recent trend. "If we can’t, it won’t be for lack of trying."

Sandra Hines | EurekAlert!
Further information:
http://www.washington.edu/

More articles from Earth Sciences:

nachricht In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>