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Huge 2004 Stratospheric Ozone Loss Tied To Solar Storms, Arctic Winds

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  • mtneuman@juno.com
    Huge 2004 Stratospheric Ozone Loss Tied To Solar Storms, Arctic Winds Boulder CO (SPX) Mar 02, 2005 A new study led by the University of Colorado at Boulder
    Message 1 of 2 , Mar 4, 2005
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      Huge 2004 Stratospheric Ozone Loss Tied To Solar Storms, Arctic Winds

      Boulder CO (SPX) Mar 02, 2005
      A new study led by the University of Colorado at Boulder indicates that
      two natural atmospheric processes in 2004 caused the largest decline in
      upper stratospheric ozone ever recorded over the far Northern Hemisphere.
      According to Research Associate Cora Randall of CU-Boulder's Laboratory
      for Atmospheric and Space Physics, nitrogen oxide and nitrogen dioxide
      gases in the upper stratosphere climbed to the highest levels in at least
      two decades in spring 2004.

      The increases led to ozone reductions of up to 60 percent roughly 25
      miles in altitude above Earth's high northern latitudes, said Randall.

      "This decline was completely unexpected," she said. "The findings point
      out a critical need to better understand the processes occurring in the
      ozone layer."

      Randall is chief author of a paper on the subject appearing in the March
      2 online issue of Geophysical Research Letters, published by the American
      Geophysical Union.

      Randall worked with an international team of scientists from the United
      States, Canada and Europe to look at data from seven different
      satellites, concluding both the sun and stratospheric weather were
      responsible for the ozone declines.

      Winds in the upper part of a massive winter low-pressure system that
      confines air over the Arctic region, known as the polar stratospheric
      vortex, sped up in February and March 2004 to become the strongest on
      record, she said.

      The spinning vortex allowed the nitrogen gases, believed by the team to
      have formed at least 20 miles above the stratosphere as a result of
      chemical reactions triggered by energetic particles from the sun, to
      descend more easily into the stratosphere.

      The increases in the two nitrogen gases - collectively known as NOx - are
      important because they are major players in the stratospheric ozone
      destruction process, said Randall.

      The team concluded that some of the extra NOx seen in the springtime was
      actually formed after huge quantities of energetic particles from the sun
      bombarded Earth's atmosphere during the Halloween solar storms of 2003.

      "No one predicted the dramatic loss of ozone in the upper stratosphere of
      the northern hemisphere in the spring of 2004," she said. "That we can
      still be surprised illustrates the difficulties in separating atmospheric
      effects due to natural and human-induced causes.

      "This study demonstrates that scientists searching for signs of ozone
      recovery need to factor in the atmospheric effects of energetic
      particles, something they do not now do."

      The 2004 enhancements of NOx gases in the upper stratosphere and
      subsequent ozone losses occurred over the Arctic and the northern areas
      of North America, Europe and Asia, said the paper authors.

      Severe ozone losses also can occur during winter and spring in the
      stratosphere at about 12 miles in altitude, driven primarily by very cold
      temperatures, they said.

      Because of seasonal conditions, the researchers are unable to measure the
      precise contributions of solar storms and stratospheric weather to the
      NOx spike seen in the stratosphere last year.

      "No observations of upper atmospheric nitrogen gases are available in the
      polar region in the winter, so the descending NOx cannot be traced to its
      origin," said Randall.

      A form of oxygen, ozone protects life on Earth from the harmful effects
      of ultraviolet radiation. The ozone layer has thinned markedly in high
      latitudes of the Northern and Southern Hemispheres in recent decades,
      primarily due to reactions involving chlorofluorocarbons and other
      industrial gases.

      Scientists believe the 1987 Montreal Protocol, an international agreement
      that has phased out the production and use of such ozone-destroying
      compounds, may allow the protective ozone layer to be restored by the
      middle of this century.

      The research team used data from satellite instruments, including POAM
      II, POAM III, SAGE II, SAGE III, HALOE, MIPAS and OSIRIS for the study.

      Co-authors on the paper include researchers from CU-Boulder, the National
      Oceanic and Atmospheric Administration, NASA, the Harvard-Smithsonian
      Center for Astrophysics in Cambridge, Hampton University and GATS of
      Hampton, Va., York University in Toronto, Chalmers University of
      Technology in Sweden and the Norwegian Institute for Air Research.

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