Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Heavy Rains Can Make More Dust in Earth’s Driest Spots

26.10.2005


Typically we think of rainfall as cleaning the air by removing dust as it falls through the atmosphere and helping plants grow that protect and hold the soil. But a new NASA-funded study looking at some of the world’s dustiest areas shows that heavy downpours can eventually lead to more dust being released into the atmosphere.



Typically drought reduces vegetation growth, increasing soil vulnerability to wind erosion, while rainfall tends to have the opposite effect. In the new study researchers examining 14 of the Earth’s dustiest regions found that in some regions, heavy rainfall and flooding leave behind sediments that include fine grain size particles that eventually get carried by winds in successive dry periods, increasing the amount of airborne dust, or emissions, released a year or more later. This is especially common in the Tigris-Euphrates Basin and in the Zone of Chotts in North Africa.

The research also confirms that dust emissions from a specific region can vary considerably from season-to-season, or year to year, and are largely dependent on climate patterns.


In some regions, "like in Oman and Saudi Arabia, where heavy rains combine with monsoon-driven winds, precipitation has a more immediate impact and appears to erode the surface crust, or top layer of soil, increasing dust emissions within just a few weeks," said Charles Zender of the Department of Earth System Science, University of California-Irvine, and lead author of the study.

Other areas of the world, including the western United States, the Great Salt Lake in Utah, eastern Sahel in Africa, and Lake Eyre basin Australia, show a more typical response, as precipitation and vegetation lessens the amount of dust released into the atmosphere. In these regions, rain and ground water help form soil layers that diminish the ability of wind to erode and carry soil particles.

Tiny dust particles have a significant influence on climate and weather patterns around the world by reflecting and absorbing sunlight and by serving as a nucleus or surface for water vapor, so that clouds can grow and form precipitation.

The researchers used information for the period 1979-1993 from many sources, including aerosol and dust data from NASA’s Total Ozone Mapping Spectrometer (TOMS) satellite, precipitation data from NASA’s Global Precipitation Climatology Project (GPCP), and the Normalized Difference Vegetation Index (NDVI) from the Advanced Very High Resolution Radiometer (AVHRR) to analyze surface vegetation cover.

Overall, in the 14 source regions studied, anomalies in dust emissions were closely related to precipitation in 12, vegetation in eight, and to wind speed in two, suggesting that rainfall is the best climate predictor of dust emissions. But other factors, including land features, elevation, the availability of loose sediments, and local distribution of water under the Earth’s surface also greatly affect dust emission.

"This study highlights the importance of soil characteristics in dust emission and shows their influence to be more prevalent than previously believed," said Zender. For instance, some soils may lack free sand-sized particles to initiate dust production, like in the Lake Eyre Basin of Australia. Other areas have soils consisting largely of clay that naturally produce less dust, while some soils may be full of sediments perfect for dust production, but are so hard and crusted that none of the particles can escape to produce dust.

While these and other factors are somewhat represented in today’s computer models, "they don’t adequately account for the formation and destruction of surface soils and how sediment supply for dust production varies from region to region," said Zender. "They also underestimate the monthly to yearly variations in dust production and its associated climate impacts."

Future computer models that address these issues will allow scientists to better predict dust production in both the short- and long-term. Such improvements are important because dust emissions have a wide impact on climate and weather, from modifying rainfall thousands of miles away, to influencing hurricane intensity and affecting air quality.

The study was published online in July 2005 in the Journal of Geophysical Research-Atmospheres.

Rob Gutro | EurekAlert!
Further information:
http://www.nasa.gov/centers/goddard/news/topstory/2005/rainfall_dust.html

More articles from Earth Sciences:

nachricht Artificial Glaciers in Response to Climate Change?
10.08.2018 | Universität Heidelberg

nachricht Planet at risk of heading towards irreversible “Hothouse Earth” state
07.08.2018 | Potsdam-Institut für Klimafolgenforschung

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

Im Focus: A molecular switch may serve as new target point for cancer and diabetes therapies

If certain signaling cascades are misregulated, diseases like cancer, obesity and diabetes may occur. A mechanism recently discovered by scientists at the Leibniz- Forschungsinstitut für Molekulare Pharmakologie (FMP) in Berlin and at the University of Geneva has a crucial influence on such signaling cascades and may be an important key for the future development of therapies against these diseases. The results of the study have just been published in the prestigious scientific journal 'Molecular Cell'.

Cell growth and cell differentiation as well as the release and efficacy of hormones such as insulin depend on the presence of lipids. Lipids are small...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

NRL's sun imaging telescopes fly on NASA Parker Solar Probe

13.08.2018 | Physics and Astronomy

UT-ORNL team makes first particle accelerator beam measurement in six dimensions

13.08.2018 | Physics and Astronomy

ASU astrophysicist helps discover that ultrahot planets have starlike atmospheres

13.08.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>