Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Human Effect on Winds Dries, Warms Springs in U.S. Southwest

20.08.2008
Since the 1970s, the winter storm track in the western U.S. has been shifting north, particularly in the late winter. As a result, there are fewer winter storms that bring rain and snow to Southern California, Arizona, Nevada, Utah, western Colorado and western New Mexico.

"We used to have this season from October to April where we had a chance for a storm," says Stephanie A. McAfee of the University of Arizona in Tucson, who is lead author of the new study. "Now it's from October to March."

The new study is the first to link the poleward movement of the westerly winds to the changes observed in the West's winter storm pattern. The change in the westerlies is driven by the atmospheric effects of global warming and the ozone hole combined.

"When you pull the storm track north, it takes the storms with it,"
McAfee says.
She and Joellen Russell, also of the University of Arizona, report their findings in an upcoming issue of Geophysical Research Letters, a journal of the American Geophysical Union.

"During the period it's raining less, it also tends to be warmer than it used to be," McAfee says. "We're starting to see the impacts of climate change in the late winter and early spring, particularly in the Southwest. It's a season-specific kind of drought."

Having drier, warmer conditions occur earlier in the year will affect snowpack, hydrological processes and water resources, McAfee says. In prior studies, other researchers have linked warmer, drier springs to more and larger forest fires.

"We're used to thinking about climate change as happening sometime in the future to someone else," Russell says. "But this is right here and affects us now. The future is here."

Atmospheric scientists have documented that the westerly winds, or storm track, have been shifting poleward for several decades. The southwestern U.S. has experienced less winter precipitation during the same period.

Computer models of future climate and atmospheric conditions suggest the storm track will continue to move north and that precipitation will continue to decrease in the southwestern U.S.

The timing of the change from wet, cool winter weather to the warmer dry season is important for many ecological processes in the arid Southwest. Therefore, McAfee wanted to know how the shift in the storm track affected precipitation during the transition from winter to spring.

For the period 1978 to 1998, the researchers compared the month- to-month position of the winter storm track, temperature and precipitation records from the western U.S., and pressure at different levels in the atmosphere.

The team used a statistical method called Monte Carlo simulations to test whether the coincidence of storm track and weather patterns had occurred by chance.

Russell says the results of the simulation showed, "It's very rare that you get this distribution by chance." Therefore, she says, the changes in late winter precipitation in the West from 1978 to 1998 are related to the changes in the storm track path for that same time period.

McAfee says her next step is investigating whether western vegetation has changed as the storm track has changed.

The National Oceanic and Atmospheric Administration funded this research.

Peter Weiss | AGU
Further information:
http://www.agu.org

More articles from Earth Sciences:

nachricht NASA sees the end of ex-Tropical Cyclone 02W
21.04.2017 | NASA/Goddard Space Flight Center

nachricht New research unlocks forests' potential in climate change mitigation
21.04.2017 | Clemson University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>