Featured Research

from universities, journals, and other organizations

Electric Sand Findings Could Lead To Better Climate Models

Date:
January 10, 2008
Source:
University of Michigan
Summary:
Wind isn't acting alone in the geological process behind erosion, sand dunes and airborne dust particles called aerosols. The other culprit is electricity. By taking both factors into account, researchers have developed a new model that matches real-world measurements of "saltation" better than the decades-old classical theory. Saltation is the process of wind blowing grains of sand across a landscape, sending them bouncing against the ground and each other. The bouncing motion of the saltating grains on the soil bed kicks dust aerosols into the air.

The above still image is from a movie showing a sample of desert soil in a metal container. The container is sitting on the lower of two metal plates between which an electric field is created. As the movie starts, the electric field is increased over 5 seconds to its final value (300 kV/m). Particles are lifted solely by the action of the electric field and bouncing around between the plates.
Credit: Courtesy of University of Michigan

Wind isn't acting alone in the geological process behind erosion, sand dunes and airborne dust particles called aerosols. The other culprit is electricity. By taking both factors into account, researchers at the University of Michigan have developed a new model that matches real-world measurements of "saltation" better than the decades-old classical theory.

Saltation is the process of wind blowing grains of sand across a landscape, sending them bouncing against the ground and each other. The bouncing motion of the saltating grains on the soil bed kicks dust aerosols into the air.

This new knowledge could lead to better climate models because it helps scientists understand how aerosols are released, U-M researchers say. Dust is one type of aerosol. Burning fossil fuels releases another type. They are known to affect Earth's climate by blocking and absorbing sunlight and seeding clouds.

Nilton Renno, associate professor in the Department of Atmospheric, Oceanic and Space Sciences, and doctoral student Jasper Kok have demonstrated that saltation creates a field of static electricity that can be strong enough to double the concentration of bouncing sand particles, compared to previous assumptions.

"The effect of aerosols is one of the most uncertain processes in climate change modeling," Kok said. "We now know more of the physics of how dust aerosols get into the atmosphere, so we should be able to improve on the way that climate models account for their emission."

Saltation itself has never been fully understood. Only recently have detailed measurements been made in nature, as opposed to in a wind tunnel. And those natural measurements disagreed with classical theory.

Renno first noticed that electricity might be missing from the equation while studying dust devils in Arizona years ago. The devils had a strong electric field.

"I was surprised at how large the field was," Renno said.

Others had suggested that electricity may be involved in saltation, but Renno said no one determined the extent of that role and created a model to describe the process including electricity, until now.

"What we discovered is as these particles bounce and rub against each other, the surface of the ground gets a positive charge and the particles get a negative charge," Renno said. "The electric field can become strong enough to directly lift sand from the surface."

The surface of the ground acts as a conductor, Kok explains, because it has a thin film of water on top.

The researchers say this model can accurately reproduce observations.

"It's a fundamental change in our understanding of the physics of saltation," Renno said.

Renno, who is a co-investigator on NASA's Phoenix and Mars Science Laboratory missions to Mars, speculates that these saltation electric fields get so large on the Red Planet they produce ground-level sparks.

The paper, "Electrostatics in wind-blown sand," will be published in the Jan. 11 issue of Physical Review Letters.

Kok and Renno's research on the basic physics of saltation and its implications to climate has been supported by the National Science Foundation's Physical and Dynamic Meteorology Program.


Story Source:

The above story is based on materials provided by University of Michigan. Note: Materials may be edited for content and length.


Cite This Page:

University of Michigan. "Electric Sand Findings Could Lead To Better Climate Models." ScienceDaily. ScienceDaily, 10 January 2008. <www.sciencedaily.com/releases/2008/01/080107125618.htm>.
University of Michigan. (2008, January 10). Electric Sand Findings Could Lead To Better Climate Models. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2008/01/080107125618.htm
University of Michigan. "Electric Sand Findings Could Lead To Better Climate Models." ScienceDaily. www.sciencedaily.com/releases/2008/01/080107125618.htm (accessed October 20, 2014).

Share This



More Matter & Energy News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Robotic Eyes' Helps Japan's Bipedal Bot Run Faster

'Robotic Eyes' Helps Japan's Bipedal Bot Run Faster

Reuters - Innovations Video Online (Oct. 16, 2014) Japanese researcher uses an eye-sensor camera to enable a bipedal robot to balance itself, while running on a treadmill. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Lockheed Martin's Fusion Concept Basically An Advertisement

Lockheed Martin's Fusion Concept Basically An Advertisement

Newsy (Oct. 15, 2014) Lockheed Martin announced plans to develop the first-ever compact nuclear fusion reactor. But some experts said the excitement is a little premature. Video provided by Newsy
Powered by NewsLook.com
First Confirmed Case Of Google Glass Addiction

First Confirmed Case Of Google Glass Addiction

Buzz60 (Oct. 15, 2014) A Google Glass user was treated for Internet Addiction Disorder caused from overuse of the device. Morgan Manousos (@MorganManousos) has the details on how many hours he spent wearing the glasses, and what his symptoms were. Video provided by Buzz60
Powered by NewsLook.com
Science Proves Why Pizza Is So Delicious

Science Proves Why Pizza Is So Delicious

Buzz60 (Oct. 15, 2014) The American Chemical Society’s latest video about chemistry in every day life breaks down pizza, and explains exactly why it's so delicious. Gillian Pensavalle (@GillianWithaG) has the video. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins