Hole over tropical West Pacific reinforcing ozone depletion in polar regions

Monday, 7 April 2014 - 12:03pm IST | Place: WASHINGTON | Agency: ANI
  • RNA Research & Archives

Researchers have found that an atmospheric hole over the tropical West Pacific is reinforcing ozone depletion in the polar regions and could have a significant influence on the climate of the Earth.

An international team of researchers headed by Potsdam scientist  Markus Rex from the Alfred Wegener Institute has discovered that above 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 manmade 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 the Earth – also because of rising air pollution in South East Asia.

At first 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 approximately 10 ppbv in the entire vertical range from the surface of the Earth to an altitude of around 15 kilometres. Normally ozone concentrations in this part of the atmosphere are three to ten times higher.

Markus Rex and his team on board the "Sonne" 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 of Atmospheric Chemistry and Physics.




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