Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The winds of change

24.01.2007
Dartmouth researchers learn that North America's wind patterns have shifted significantly in the past 30,000 years

Dartmouth researchers have learned that the prevailing winds in the mid latitudes of North America, which now blow from the west, once blew from the east. They reached this conclusion by analyzing 14,000- to 30,000-year-old wood samples from areas in the mid-latitudes of North America (40-50°N), which represents the region north of Denver and Philadelphia and south of Winnipeg and Vancouver.

The researchers report their findings online on Jan. 23 in the journal Geology, published by the Geological Society of America.

"Today in the mid-latitude zone of North America, marine moisture is transported either from the west coast by westerly winds, or from both the west and east coasts by storms," says Xiahong Feng, the paper's lead author and a professor of earth sciences. "In this study, we found evidence that during the last glacial period, about 14-36 thousand years ago, the prevailing wind in this zone was easterly, and marine moisture came predominantly from the East Coast."

Feng explains that global climate change is often manifested by changes in general atmospheric circulation, i.e. winds, and this results in changing temperature and precipitation patterns. Clues of past climates usually hint at temperature and precipitation changes, but this is the first time that changing continental wind patterns have been reconstructed.

The researchers gathered their evidence using oxygen and hydrogen isotopic compositions of cellulose extracted from ancient wood. Feng and her team interpret the historic prevailing easterlies to be a result of a growing and intensifying northern circumpolar vortex, which was influenced by the powerful Laurentide Ice Sheet, an enormous mass of ice that covered a great deal of northern North America. Under this circulation regime, the jet stream shifted southward, and as a result, the Pacific Northwest received much less marine moisture from the Pacific. This is consistent with earlier studies of vegetation in the Pacific Northwest, indicating that the region was significantly drier during the last glaciation.

Dartmouth researchers look at ancient wood to determine 30,000-year-old wind patterns.

"This study is likely to open up new avenues of research based on oxygen and hydrogen isotopes in old wood," says Feng. "Climate change involves interactions among temperature, precipitation, and wind, but until now research has rarely been able to observe or confirm prehistoric winds and their continental-scale patterns. In the future, studies using this methodology will be able to look into ancient climates through a new window, and test hypotheses about climate change mechanisms. Such studies can potentially lead to more realistic formulations of future climate scenarios and better evaluations of their plausibility."

In addition to Xiahong Feng, who also holds the Frederick Hall Professorship in Mineralogy and Geology at Dartmouth, other authors on the paper include: Allison L. Reddington, a member of the Dartmouth Class of 2004; Anthony M. Faiia, Dartmouth research associate; Eric S. Posmentier, adjunct professor of earth sciences at Dartmouth; Yong Shu, Dartmouth PhD candidate; and Xiaomei Xu, from the Earth System Science Department at the University of California, Irvine.

"This study began as Allison Reddington's undergraduate honors thesis," says Feng. "This exemplifies the extraordinary opportunities that undergraduates at Dartmouth have to become integral parts of research groups."

Sue Knapp | EurekAlert!
Further information:
http://www.dartmouth.edu

More articles from Earth Sciences:

nachricht New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland
19.01.2017 | University of Gothenburg

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>