Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Amount of dust, pollen matters for cloud precipitation, climate change

08.06.2010
A lot of large particles of dust and pollen in the atmosphere may make your nose twitch, but they can lead directly to greater precipitation in clouds, Colorado State University atmospheric scientists have discovered for the first time.

The amount of ice crystals necessary to form precipitation in clouds is linked to the abundance of larger aerosol particles in the atmosphere, according to a study by Paul DeMott and Anthony Prenni, research scientists in the Atmospheric Science department at Colorado State. Their findings appear in this week’s issue of the Proceedings of the National Academy of Sciences.

Using these new findings, a global climate model predicted that clouds have a stronger cooling effect on the globe than previously estimated. However, future increases in these ice nuclei for cold clouds would reduce the cooling impact on climate and vice versa, the scientists found.

Special particles called aerosols – resulting from desert dust, some biological processes and possibly from pollution – are needed as catalysts to form ice in clouds, which can influence precipitation and cloud dynamics. These particles can serve as the center, or nuclei, for cloud droplets that combine to form raindrops.

“The catalysts for most ice nuclei are primary emissions – from pollution or sea spray or dust,” DeMott said. “The bigger the particles, the better it is for ice nuclei.”

At the same time, pinpointing a number of particles at a specific temperature is too simple for climate models to accurately represent what’s occurring in nature, DeMott said.

Scientists have spent decades trying to understand the processes. The National Science Foundation, the National Oceanic and Atmospheric Administration, the U.S. Department of Energy and NASA have funded Colorado State’s research in this area.

DeMott and Prenni analyzed data from 14 years of trips across the globe from the Amazon Rainforest in Brazil to the Arctic to Broomfield, Colo., to collect air samples in specially equipped National Center for Atmospheric Research planes. The Colorado State scientists also developed the first instrument –for use inside the plane – to take continuous air samples from in and around clouds and measure in real time the ice-forming ability of particles. The instrument allows the researchers to sample air and detect the total number concentrations of ice nuclei without first putting them on a filter or other processing.

How capturing air from a plane works: CSU scientists take air samples into a small chamber through a special port on the side of a C-130 plane. A diffusion chamber cools and humidifies the air and particles between two plates of ice toward conditions where ice forms, essentially "growing" clouds by simulating the conditions in the atmosphere. Researchers then evaluate how many particles will form ice crystals for specific cloud conditions. The plane then passes through the wave clouds to measure, with other instruments, how much ice really forms.

Scientists also used specialized instruments to determine the chemical makeup of the particulates forming ice.

“Ice nuclei are hard to measure – they’re microns in size like the size of a bacteria,” Prenni said. “They don’t make haze – there aren’t enough of them. Of all the particles in the atmosphere, one in a million particles in the atmosphere can cause ice to form.”

In March, Prenni and DeMott published an article in Atmospheric Environment that examined the role biological particles – from plants, bacteria or other living things on Earth – play in characterizing atmospheric concentrations and types of ice nuclei. They concluded that much more work needs to be done in tandem with biologists to determine numbers and sources of these particles as a function of season and temperature range.

“The people who look at snow and find these bacteria in it don't know if the bacteria were in fact the ice nuclei or how many of them there are floating around in the air in various places/seasons,” said Sonia Kreidenweis, professor of atmospheric science who works with DeMott and Prenni. “There could be too few to matter. We are actually making these measurements in the air to try to nail this down.”

“We don’t know if we can identify all the biological particles,” DeMott said. “What are the most effective ones? Their amounts matter as well. Is there any way that they play a role in cloud processes?”

Colorado State’s atmospheric chemists have been recognized internationally for cutting-edge research in their fields:

• Prenni’s NASA-sponsored research in Brazil, for example, led to a paper in Nature Geosciences that showed, for the first time, data on ice-nucleus concentration and elemental composition in the Amazon basin. He and Markus Petters, also a research scientist at CSU, took measurements for two months as part of the Amazonian Aerosol Characterization Experiments along with scientists from Harvard University and the Max Plank Institute in Germany.

• Prenni is now leading a CSU effort on a new NSF-sponsored project to study similar processes in Colorado. In addition to the Atmospheric Science group, this collaborative project includes the Colorado State Proteomics and Metabalomics Core Facility, as well as researchers from the University of Colorado and the National Center for Atmospheric Research.

• Kreidenweis was one of 15 researchers nationally who served on the National Research Council’s committee on the Significance of International Transport of Air Pollutants. The committee issued a report in September 2009 reviewing scientific evidence that plumes of air pollutants can have a negative impact on air quality far from their original sources.

The Department of Atmospheric Science at Colorado State has been designated by the university as a Program of Research and Scholarly Excellence and is home to two of only a dozen University Distinguished Professors - Graeme Stephens and Tom Vonder Haar. Stephens and his team were at the helm of one of the very few university-led NASA Earth Science missions with the 2006 launch of CloudSat, the world's first cloud-profiling radar in orbit.

Emily Wilmsen | EurekAlert!
Further information:
http://www.colostate.edu

More articles from Earth Sciences:

nachricht Less radiation in inner Van Allen belt than previously believed
21.03.2017 | DOE/Los Alamos National Laboratory

nachricht Mars volcano, Earth's dinosaurs went extinct about the same time
21.03.2017 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Pulverizing electronic waste is green, clean -- and cold

22.03.2017 | Materials Sciences

Astronomers hazard a ride in a 'drifting carousel' to understand pulsating stars

22.03.2017 | Physics and Astronomy

New gel-like coating beefs up the performance of lithium-sulfur batteries

22.03.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>