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/

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Staying in Shape

16.08.2018 | Life Sciences

Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter

16.08.2018 | Earth Sciences

Protein droplets keep neurons at the ready and immune system in balance

16.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>