Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Satellites Search for 770M Tons of Dust in the Air

14.09.2010
Using data from several research satellites, scientists at The University of Alabama in Huntsville will spend the next three years trying to understand the climate impacts of about 770 million tons of dust carried into the atmosphere every year from the Sahara.

Some Saharan dust falls back to Earth before it leaves Africa. Some of it streams out over the Atlantic Ocean or Mediterranean Sea, carried on the wind as far away as South America and the Southeastern United States. All of it has an as-yet unmeasured impact on Earth's energy budget and the climate by reflecting sunlight back into space.

"The people who build climate models make some assumptions about dust and its impact on the climate," said Dr. Sundar Christopher, a professor of atmospheric science at UAHuntsville. "We want to learn more about the characteristics of this dust, its concentrations in the atmosphere and its impact on the global energy budget so we can replace those assumptions with real data."

Dust is one kind of particle, or aerosol, that floats around in the atmosphere. Most of the recent research into aerosols has focused on particles made by humans, such as smoke, soot or other types of pollution.

"There has been a lot of research looking at the climate effects of man-made aerosols," Christopher said. "Particles from smoke and burning fossil fuels are tiny, sub-micron size. These tiny particles cool the atmosphere because they reflect sunlight back into space before it has a chance to heat the air. That means less solar energy is available at the surface to heat the planet."

Because they are so small, pollution aerosols don't have a significant effect on heat energy. That's why they usually have a net cooling effect on the atmosphere.

Dust particles, on the other hand, weighing in at a hefty 10+ microns (a human hair is about 100 microns in diameter) do absorb some solar radiation, convert it to heat and release that heat into the air. They also reflect some radiation back into space, so dust both heats and cools the atmosphere.

More importantly they have a significant effect on heat energy in the air. Dust absorbs thermal energy rising from the ground and re-radiates it either toward space (and colder temperatures) or back toward the surface.

"One thing we want to do is calculate how reflective dust is, because not all dust is created equal," Christopher said. "We're trying to calculate reflectivity so we can say with precision how much sunlight is being reflected."

The composition and shape of dust particles is very complex. They are not spherical, which makes calculating their energy budget challenging and time consuming. Also, the composition of dust varies depending on which part of the Sahara the dust comes from. Some of it absorbs more solar energy than others.

"Climate models are not very sophisticated in the way they handle dust," Christopher said. "And the long-wave or infrared part is something that has been ignored for a long time. We want to nail down those values."

Why start with the Sahara? First, the Sahara contributes about half of all of the dust carried into Earth's atmosphere every year. The Saharan dust is also more "pristine" than dust from U.S. or Asian deserts. Dust from U.S., Chinese or Mongolian deserts frequently mixes with pollution to create an aerosol stew, which can make it difficult to study just the dust.

Studying the Saharan dust is enough of a challenge, in part because it is made of the same stuff as the desert underneath. That means the dust in the atmosphere looks very much like the surface below it. Only in the past few years have new instruments and new techniques been developed that help scientists "see" which is dust and which is desert.

Christopher has received a grant of almost $500,000 through NASA's CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) program to support the research for the next three years. The CALIPSO satellite's instruments include a LIDAR, which shoots a laser into the atmosphere then catches light that bounces off particles in the air to learn more about aerosols.

Dr. Sundar Christopher, 256.961.7872
sundar.christopher@nsstc.uah.edu
Phillip Gentry, 256.961.7618
gentry@nsstc.uah.edu

Phillip Gentry | Newswise Science News
Further information:
http://www.nsstc.uah.edu

More articles from Earth Sciences:

nachricht Clear as mud: Desiccation cracks help reveal the shape of water on Mars
20.04.2018 | Geological Society of America

nachricht Hurricane Harvey: Dutch-Texan research shows most fatalities occurred outside flood zones
19.04.2018 | European Geosciences Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>