Newly discovered atmospheric layer may impact earth's climate 'Like a giant elevator to the stratosp

'Like a giant elevator to the stratosphere:' Newly discovered atmospheric layer may impact earth's climate

An international team of researchers has discovered a previously unknown atmospheric phenomenon over the tropical West Pacific. Like in a giant elevator to the stratosphere, many chemical compounds emitted at the ground pass unfiltered through the so-called 'detergent layer' of the atmosphere, known as the 'OH shield.' The newly discovered phenomenon over the South Seas boosts ozone depletion in the polar regions and could have a significant influence on the future climate of the Earth.




An international team of researchers headed by Potsdam scientist Dr. Markus Rex from the Alfred Wegener Institute has discovered a previously unknown atmospheric phenomenon over the South Seas. Over the tropical West Pacific there is a natural, invisible hole extending over several thousand kilometres in a layer that prevents transport of most of the natural and humanmade substances into the stratosphere by virtue of its chemical composition. Like in a giant elevator, many chemical compounds emitted at the ground pass thus unfiltered through this so-called "detergent layer" of the atmosphere. Scientists call it the "OH shield." The newly discovered phenomenon over the South Seas boosts ozone depletion in the polar regions and could have a significant influence on the future climate of Earth -- also because of rising air pollution in South East Asia.

At first Dr. Markus Rex suspected a series of flawed measurements. In October 2009 the atmospheric physicist from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) was on board the German research vessel "Sonne" to measure trace substances in the atmosphere in the tropical West Pacific. Tried and tested a thousand times over, the ozone probes he sent up into the tropical sky with a research balloon every 400 kilometres reported -- nothing. Or to be more accurate: almost nothing. The ozone concentrations in his measurements remained nearly constantly below the detection limit of approx. 10 ppbv in the entire vertical range from the surface of Earth to an altitude of around 15 kilometres. Normally ozone concentrations in this part of the atmosphere are three to ten times higher. (One part of ozone per billion by volume (ppbv) means there is one ozone molecule for every billion air molecules.)

Although low values at an altitude of around 15 kilometres were known from earlier measurements in the peripheral area of the tropical West Pacific, the complete absence of ozone at all heights was surprising. However, after a short period of doubt and various tests of the instruments it dawned on the worldwide recognized ozone specialist that he might be onto a phenomenon yet unknown to science. A few research years later and after the involvement of other colleagues came confirmation: Markus Rex and his team on board the "Sonne" had tracked down a giant natural hole over the tropical South Seas, situated in a special layer of the lower atmosphere known as the "OH shield." The research results on the newly discovered OH minimum will be published soon in the journal Atmospheric Chemistry and Physics, with the Institute of Environmental Physics of the University of Bremen and other international research institutions as partners.

http://www.sciencedaily.com/releases/2014/04/140404092931.htm