In March 2006, the winds allowed near-record amounts of ozone- destroying gases, collectively known as nitrogen oxides or NOx, to descend some 50 kilometers [30 miles] from the mesosphere to the top of Earth's stratosphere.
NOx, is a generic term for a group of highly reactive gases, all of which contain nitrogen and oxygen in varying amounts, especially nitric oxide and nitrogen dioxide. Because NOx destroys ozone, which heats up the stratosphere by absorbing ultraviolet radiation, the naturally occurring gases could trigger atmospheric changes that could have unanticipated climate consequences, according to Cora Randall of the University of Colorado at Boulder, lead author of the study.
In February 2006, winds in the polar upper stratospheric vortex, a massive winter low-pressure system that confines air over the Arctic region, sped up to rival the strongest such winds on record, said Randall. The only time more nitrogen oxides were observed in the upper stratosphere was in the winter of 2003-2004, when huge solar storms bombarded the region with energetic particles, triggering up to a 60 percent reduction in ozone molecules, said Randall.
"We knew strong winds would lead to more NOx in the stratosphere if there were solar storms, but seeing that much NOx come down into the stratosphere when the Sun was essentially quiet was amazing,” Randall said. Her paper on the subject was published 27 September in Geophysical Research Letters, published by the American Geophysical Union. Researchers from the University of Waterloo in Ontario, Canada, and the University of Michigan, as well as the University of Colorado participated in the study.
The upper stratosphere lies several kilometers [miles] higher than the ozone hole of the lower stratosphere, which is caused by man- made gases, including chlorine and bromine, which gobble up ozone molecules. Because there is significantly less ozone in the upper stratosphere, the ozone-destroying nitrogen oxide gases are unlikely to cause immediate health threats, such as increases in skin cancer, Randall said.
The destructive NOx gases, created above the stratosphere when sunlight or energetic particles break apart oxygen and nitrogen molecules, appear to be important players in controlling the temperature of Earth's middle atmosphere, according to Randall. "If human-induced climate change leads to changes in the strength of the polar vortex, which is what scientists predict, we'll likely see changes in the amount of NOx descending into the stratosphere,” she said. "If that happens, more stratospheric NOx might become the rule rather than the exception."
"The atmosphere is part of a coupled system, and what affects one layer of the atmosphere can influence other layers in surprising ways," Randall said. "We will only be able to predict and understand the consequences of human activities if we study the entire system as a whole, and not just in parts."
The 2006 increases of NOx in the upper stratosphere occurred over the Arctic and the northern areas of North America and Europe, according to the paper's authors. The research team used data from Canadian and United States satellites, including the Canadian Atmospheric Chemistry Experiment.
The work was funded by NASA and the Canadian Space Agency.
Harvey Leifert | AGU
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Materials Sciences
18.07.2018 | Health and Medicine