As thousands of travelers to and from Europe remain grounded by the plumes of ash that Iceland's Eyjafjallajokull volcano propelled into the atmosphere, many scientists—at least those not stranded themselves—have geared up to figure out what chemistry is going on in the cloud of ash.
Earlier today, Germany's Aerospace Center sent up a twin-engine jet called the Falcon 20E to measure the ash aerosols and gases in the plume. Although several commercial airline companies have flown planes through the ash cloud to evaluate possible risks to aircraft, "there's a difference to seeing if a plane still works versus doing actual research measurements," says Jan Wörner, the center's chairman of the board. German authorities will use the data to determine whether and when airspace in the country can be reopened for commercial flight, Wörner says.
In particular, researchers want to measure the mass concentration of the ash particles in the atmosphere and compare that with the computer simulations made by London's Volcanic Ash Advisory Center. Several airlines have questioned the accuracy of those simulations, which were used as the basis for closing much of Northern Europe's airspace after the eruption. Researchers also hope to measure the levels of gases such as sulfur dioxide in the ash cloud, because sulfur dioxide can react and coat the aerosol particles, solubilizing them so that they can exit the atmosphere quicker with rain, explains Jos Lelieveld, a director at the Max Planck Institute for Chemistry, in Mainz, Germany, who specializes in atmospheric science.
The DLR's experiment is just one of several in Europe aimed at getting actual atmospheric data from the ash cloud. In the U.K., the Facility for Airborne Atmospheric Measurements has sent their Dornier 228 ARSF aircraft to "characterize the volcanic ash plume," notes their website. In Switzerland, scientists stationed at the Jungfraujoch research station in the Alps have been taking data since the ash cloud began to pass by, says Urs Baltensperger, head of atmospheric chemistry at the Paul Scherrer Institute, which coordinates the aerosol measurements at the Jungfraujoch research station.
Baltensperger says that even though the Jungfraujoch station is not located at an altitude in the thickest of the volcano's plumes, its scientists could measure the aerosols' mass concentration anyway and found them to be low. He claims that regulators' choices would have been justified only if the maximum mass concentration of the plume were one hundred times the levels Jungfraujoch scientists measured.
He adds that the research community is excited by the data opportunities afforded by the eruption. "I spent the weekend in front of my computer e-mailing with scientists all over the world discussing the [volcanic eruption]," he says.
Bruno Neininger, a pilot and CEO of Zurich-based Metair, which does atmospheric measurements, took a motorized glider into the plumes in Switzerland over the weekend to measure the concentration of aerosol particles. "He told me he could smell the plume," Baltensperger says.
Although most experiments right now are aimed at providing regulators with data to determine whether airspaces should remain closed, researchers are looking forward to doing other more fundamental experiments. Roland von Glasow, an atmospheric scientist at the University of East Anglia, in the U.K., is particularly interested in how the ash is being transformed during transport by oxidation in the atmosphere. He also hopes to look at the halogens released by the volcano. In particular, he wants to study bromine oxides and how they react with mercury in the air. The reaction could transform the mercury into a form that deposits more easily out of the atmosphere, onto Earth, and possibly into the food chain.
Other researchers located in Iceland are taking samples of the ash itself for chemical analysis. Understanding the composition of the ash and by association, the magma, may help scientists figure out how long the volcano will continue to erupt.
Lelieveld hopes that there will be an opportunity to acquire data that can give climate modelers a better idea how volcanoes can affect the atmosphere and climate in general. He's says he's disappointed that geo-stationary satellites weren't yet equipped with tools that can measure aerosols continuously.