Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

U. of Colorado researchers propose answer to basic atmospheric chemistry question

07.03.2003


Scientists from the University of Colorado at Boulder have proposed a long-sought answer to how atmospheric sulfate aerosols are formed in the stratosphere.



Conducted by researchers at the Cooperative Institute for Research in Environmental Sciences, or CIRES, the research shows how a fundamental molecular process driven by sunlight may play a significant role in determining the planet’s energy budget.

The research was a collaboration between Veronica Vaida, chair of the CU-Boulder chemistry and biochemistry department and a CIRES fellow, CIRES visiting fellows H. G. Kjaergaard from the University of Otago in New Zealand and D. J. Donaldson from the University of Toronto, and CIRES doctoral candidate P. E. Hintze.


A paper on the subject will appear in the March 7 issue of Science magazine. CIRES is a joint institute of CU-Boulder and the National Oceanic and Atmospheric Administration headquartered on campus.

Atmospheric sulfates gather in a stratospheric region called the Junge layer that surrounds Earth’s surface at altitudes between nine and 21 miles, said Vaida. The Junge layer reflects sunlight back into space and radiation to Earth, affecting the planet’s energy budget.

The Junge layer is thought to be composed primarily of sulfuric acid and water molecules, she said. Because sulfates have important chemical and climate effects, scientists have wanted to understand how atmospheric sulfuric acid breaks down, releasing sulfur oxides in the upper stratosphere where concentrations have been measured.

When high-altitude air descends in the cold polar vortex each spring, the gases recombine and form the Junge layer, Vaida said. Sunlight can be absorbed by sulfuric acid molecules and in some instances decompose them.

"It was thought that solar radiation could break the bonds of sulfuric acid molecules at very high energies in the ultraviolet spectrum," Vaida said. But high-energy radiation is present only at the top of and above the atmosphere because the atmosphere effectively absorbs ultraviolet radiation.

"We ruled out the standard hypothesis that had been proposed but never observed," Vaida said. Instead, she said, the CIRES team sought ways that the sulfates could be breaking down within the visible range of light.

In order to explain the measured and modeled concentrations of sulfates found in the upper stratosphere and mesosphere, "The mechanism we proposed was really the only game in town," she said.

Using spectroscopy, the team investigated the effect of visible light on sulfuric acid molecules to prove that molecular rearrangements could be induced to explain the observed sulfate layer. "We found visible radiation at much lower energies than previously thought could accomplish the molecular breakdown," Vaida said.

"Understanding the fundamental properties of sulfuric acid, we now know what affects formation of the sulfate layer, and can predict its formation by looking at the altitude, temperature and solar flux," she said. "The work allows us to model chemical properties of the Earth’s atmosphere."

Support for the research was provided by the National Science Foundation, the Marsden Fund administered by the Royal Society of New Zealand and NSERC of Canada. Vaida credits the success for the team’s discovery to the CU-NOAA partnership at CIRES that unites university academic departments with eight NOAA laboratories. The collaboration produces an increased flow of ideas and additional access to specialized expertise.

"We had a lot of help from NOAA people uniquely qualified in the areas that we needed – the connection fostered by CIRES was key," she said. "We could bring together fundamental chemistry with atmospheric science in a way that can’t be done anywhere else – it was rather magical."

The next step is "to quantify the yield with which sulfur oxides are going to be released and refining our knowledge of related processes," Vaida said.


Contact: Veronica Vaida, (303) 492-8605
vaida@spot.colorado.edu
Annette Varani, (303) 492-5952
Nicolle Wahl, (416) 978-6974
Nicolle.wahl@utoronto.ca


Veronica Vaida | EurekAlert!

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Molecular volume control

22.08.2017 | Life Sciences

When fish swim in the holodeck

22.08.2017 | Life Sciences

Biochemical 'fingerprints' reveal diabetes progression

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>