Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Airborne dust causes ripple effect on climate far away

30.01.2007
When a small pebble drops into a serene pool of water, it causes a ripple in the water in every direction, even disturbing distant still waters.

NASA researchers have found a similar process at work in the atmosphere: tiny particles in the air called aerosols can cause a rippling effect on the climate thousands of miles away from their source region.

The researchers found that dust particles from the desert regions in northern Africa can produce climate changes as far away as the northern Pacific Ocean. Large quantities of dust from North Africa are injected into the atmosphere by dust storms and rising air. Airborne dust absorbs sunlight and heats the atmosphere. The heating effect ripples through the atmosphere, affecting surface and air temperatures as the dust travels.

"These highs and lows in air temperatures caused by radiation-absorbing aerosols can lead to 'teleconnection’, which refers to changes in weather and climate in one place caused by events happening far away, often more than half way around the globe," said William Lau, Chief of the Laboratory for Atmospheres at NASA's Goddard Space Flight Center, Greenbelt, Md., and author of a study published last fall in the American Meteorological Society's Journal of Climate. "North African dust can be lifted high into the atmosphere by storms and then transported across the Atlantic and Caribbean, where its effect can be far-reaching."

From a climate point of view, aerosols can block solar radiation (incoming heat and light from the sun) from hitting the Earth's land surface. When sunlight is blocked, it can cause the Earth's surface to cool, and/or the aerosols can absorb solar radiation and cause the atmosphere in the vicinity of the airborne dust to get warmer.

According to Lau, researchers thought for years that heat changes in the atmosphere from aerosols only caused local changes in temperatures. However, "we now know they may cause more than local changes to climate," he said. Lau's computer model indicates that the heat changes caused by aerosols affect the heat balance in the air over North Africa. That change in heat creates large waves in the atmosphere that ripple as far away as Eurasia and the North Pacific.

Researchers have created complex numerical models to simulate the "still waters" of the atmosphere during North African spring – a season when climate conditions are relatively calm with light winds and light rain.

Lau's team carried out a numerical model experiment that included aerosol forcing, and then another one with identical initial conditions and lower boundary conditions, except that the aerosol forcing is removed. By comparing the weather patterns in the two experiments, they can deduce the effect of aerosol forcing. They observed the aerosols made an impact far away from their source region. In setting up their experiment, the researchers chose the northern Sahara Desert in springtime, when the weather conditions are relatively calm, allowing aerosols, like dust, to build up more in air.

An "atmospheric teleconnection" happens when unusual patterns of air pressure and air circulation happen in one place, and the energy is dispersed over large distances around the globe to other places. An atmospheric teleconnection can lead to changes in sea level pressure and temperature around the world. This study saw changes from North Africa through Eurasia to the North Pacific.

Most interesting, Lau's team found that North African-dust teleconnection led to strong cooling over the Caspian Sea (a land-locked body of water between Russia and Europe) and warming over central and northeastern Asia, where man-made aerosol concentrations are low.

"Elevated aerosols in large quantities such as dust from North Africa, or biomass burning may have global impacts," said Lau. "We expect to observe more and more real-world examples of this teleconnection phenomenon with the high volume of aerosols generated by nature and human activities around the world."

Lynn Chandler | EurekAlert!
Further information:
http://www.nasa.gov
http://www.nasa.gov/centers/goddard/news/topstory/2006/particle_ripple.html

More articles from Earth Sciences:

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

nachricht NASA spies Tropical Cyclone 08P's formation
23.02.2017 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>