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 How is climate change affecting fauna in the Arctic?
22.05.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Sea level as a metronome of Earth's history
19.05.2017 | Université de Genève

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

Im Focus: Hydrogen Bonds Directly Detected for the First Time

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

Media accreditation opens for historic year at European Health Forum Gastein

16.05.2017 | Event News

 
Latest News

New approach to revolutionize the production of molecular hydrogen

22.05.2017 | Materials Sciences

Scientists enlist engineered protein to battle the MERS virus

22.05.2017 | Life Sciences

Experts explain origins of topographic relief on Earth, Mars and Titan

22.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>