The escalation in dust emissions — which may be due to the interplay of several factors, including increased windstorm frequency, drought cycles and changing land-use patterns — has implications both for the areas where the dust is first picked up by the winds and for the places where the dust is put back down.
This image shows a dust storm in Canyonlands National Park.
Credit: Jason Neff
"Dust storms cause a large-scale reorganization of nutrients on the surface of the Earth," said Janice Brahney, who led the study as a CU-Boulder doctoral student. "And we don't routinely monitor dust in most places, which means we don't have a good handle on how the material is moving, when it's moving and where it's going."
Based on anecdotal evidence, such as incidents of dust coating the snowpack in the southern Rockies and a seemingly greater number of dust storms noticed by Western residents, scientists have suspected that dust emissions were increasing. But because dust has not been routinely measured over long periods of time, it was difficult to say for sure.
"What we know is that there are a lot of dust storms, and if you ask people on the Western Slope of Colorado, or in Utah or Arizona, you'll often hear them say, 'Yeah, I grew up in this area, and I don't remember it ever being like this before,'" said CU-Boulder geological sciences Associate Professor Jason Neff, Brahney's adviser and a co-author of the paper. "So there is anecdotal evidence out there that things are changing, but no scientific data that can tell us whether or not that's true, at least for the recent past."
For the new study, recently published online in the journal Aeolian Research, the research team set out to determine if they could use calcium deposition as a proxy for dust measurements. Calcium can make its way into the atmosphere — before falling back to earth along with precipitation — through a number of avenues, including coal-fired power plants, forest fires, ocean spray and, key to this study, wind erosion of soils.
The amount of calcium dissolved in precipitation has long been measured by the National Atmospheric Deposition Program, or NADP, which first began recording the chemicals dissolved in precipitation in the late 1970s to better understand the phenomena of acid rain.
Brahney and her colleagues reviewed calcium deposition data from 175 NADP sites across the United States between 1994 and 2010, and they found that calcium deposition had increased at 116 of them. The sites with the greatest increases were clustered in the Northwest, the Midwest and the Intermountain West, with Colorado, Wyoming and Utah seeing especially large increases.
The scientists were able to determine that the increase was linked to dust erosion because none of the other possible sources of atmospheric calcium — including industrial emissions, forest fires or ocean spray — had increased during the 17-year period studied.
It's also likely that the calcium deposition record underrepresents the amount of dust that's being blown around, said Brahney, who is now a postdoctoral researcher at the University of British Columbia in Canada. That's because the NADP network only measures dust that has collided with water in the atmosphere before precipitating to earth — not dust that is simply moved by the wind. And not all dust contains the same amount of calcium.
The increase in dust erosion matters, the researchers said, because it can impoverish the soil in the areas where dust is being lost. Wind tends to pick up the finer particles in the soils, and those are the same particles that have the most nutrients and can hold onto the most soil moisture, Brahney said.
Increasing amounts of dust in the atmosphere also can cause people living in the rural West a variety of problems, including poor air quality and low visibility. In extreme cases, dust storms have shut down freeways, creating problems for travelers.
The areas where the dust travels to are also affected, though the impacts are more mixed. When dust is blown onto an existing snowpack, as is often the case in the Rockies, the dark particles better absorb the sun's energy and cause the snowpack to melt more quickly. But the dust that's blown in also brings nutrients to alpine areas, and the calcium in dust can buffer the effects of acid rain.
In the future, researchers working in Neff's lab hope to get a more precise picture of dust movement by measuring the dust itself. In the last five years, large vacuum-like measuring instruments designed specifically to suck in dust emissions have been installed at sites between the canyon lands of Utah and the Front Range of the Rockies. Once scientists have enough data collected, they'll be able to look for trends in dust emissions without relying on proxies.
The study was funded by the National Science Foundation.
Jason Neff | EurekAlert!
Ice cave in Transylvania yields window into region's past
28.04.2017 | National Science Foundation
Citizen science campaign to aid disaster response
28.04.2017 | International Institute for Applied Systems Analysis (IIASA)
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences