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Columbia team shows how stratospheric conditions affect weather

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  • patneuman2000
    ... wrote: Earth Institute News posted 12/06/04 Contact: Mary Tobin 845-365-8607 or mtobin@l... Contact: Katie Mastriani 212-854-1244 or
    Message 1 of 1 , Dec 10, 2004
      --- In Paleontology_and_Climate_Articles@yahoogroups.com, sonya koch
      <msredsonya@e...> wrote:

      Earth Institute News

      posted 12/06/04

      Contact: Mary Tobin
      845-365-8607 or mtobin@l...

      Contact: Katie Mastriani
      212-854-1244 or km644@c...

      Columbia Team Shows How Stratospheric Conditions Affect Weather
      New research may improve long-term forecasting skills

      The authors, left to right: Andrew Charlton, postdoctoral student;
      Matthew Wittman, graduate student and principal author; and Lorenzo
      Polvani, Professor of Applied Physics and Applied Mathematics & Earth
      and Environmental Sciences and Director of the IGERT Joint Program in
      Applied Mathematics and Earth and Environmental Sciences.


      by Jennifer Freeman

      Three members of Columbia?s Department of Applied Physics and Applied
      Mathematics have used a simple climate model to demonstrate how the
      weather systems and storms we experience may be influenced by
      disturbances in the Earth?s stratosphere, the upper layer of
      atmosphere between 10 and 30 miles high. This Earth Institute research
      was recently highlighted by the American Geophysical Union, following
      recent publication in the journal Geophysical Research Letters.

      ?Our research shows that changes to the strength of winds in the
      stratosphere cause changes to tropospheric weather systems? explained
      lead-author Matthew Wittman.

      Understanding how the stratosphere affects the troposphere, the
      lowermost layer of the atmosphere where weather occurs, is important
      to improving seasonal weather forecasts and predicting the effect of
      ozone depletion and global warming on our climate.

      ?The stratosphere has a longer ?memory? than the troposphere,? adds
      co-author Andrew Charlton. ?If you want to make forecasts on a time
      scale longer than several days, it is useful to understand the
      mechanisms linking places with longer memories, such as the
      stratosphere and the oceans to the troposphere.?

      The above map shows a snapshot of surface temperature in the Northern
      Hemisphere, with weather systems moving poleward. In the paper, the
      authors demonstrate that this process is influenced by the presence of
      a stratospheric jet.


      Each winter a westerly jet - called the Polar Night Jet - forms in the
      stratosphere. Winds in this jet circulate around the pole at speeds of
      up to 100 miles per hour. The strength of this jet changes as part of
      normal atmospheric variability, and possibly also in response to
      climate change. In their new research, the authors show that the
      presence of stronger westerly jets in the stratosphere causes
      tropospheric weather systems to track further towards the pole.

      Averaging the changes to the paths of weather systems, the research
      team showed, produces a pattern of changes similar in structure to the
      Arctic Oscillation, the dominant pattern of climate variability in the
      Northern Hemisphere that describes how temperatures across the whole
      hemisphere vary together.

      The research is part of the team?s ongoing efforts to understand the
      interaction of the stratosphere and troposphere and improve the
      representation of this interaction in climate models. The Columbia
      co-authors - Matthew Wittman, Lorenzo Polvani, Richard Scott and
      Andrew Charlton - are affiliated with the climate research group at
      the Earth Institute at Columbia.

      The Earth Institute at Columbia University is the world?s leading
      academic center for the integrated study of Earth, its environment and
      society. The Earth Institute builds upon excellence in the core
      disciplines - earth sciences, biological sciences, engineering
      sciences, social sciences and health sciences - and stresses
      cross-disciplinary approaches to complex problems. Through research,
      training and global partnerships, it mobilizes science and technology
      to advance sustainable development, while pl







      Earth Institute News

      posted 12/06/04

      Contact: Mary Tobin
      845-365-8607 or mtobin@l...

      Contact: Katie Mastriani
      212-854-1244 or km644@c...

      Columbia Team Shows How Stratospheric Conditions Affect Weather
      New research may improve long-term forecasting skills

      The authors, left to right: Andrew Charlton, postdoctoral student;
      Matthew Wittman, graduate student and principal author; and Lorenzo
      Polvani, Professor of Applied Physics and Applied Mathematics & Earth
      and Environmental Sciences and Director of the IGERT Joint Program in
      Applied Mathematics and Earth and Environmental Sciences.


      by Jennifer Freeman

      Three members of Columbia?s Department of Applied Physics and Applied
      Mathematics have used a simple climate model to demonstrate how the
      weather systems and storms we experience may be influenced by
      disturbances in the Earth?s stratosphere, the upper layer of
      atmosphere between 10 and 30 miles high. This Earth Institute research
      was recently highlighted by the American Geophysical Union, following
      recent publication in the journal Geophysical Research Letters.

      ?Our research shows that changes to the strength of winds in the
      stratosphere cause changes to tropospheric weather systems? explained
      lead-author Matthew Wittman.

      Understanding how the stratosphere affects the troposphere, the
      lowermost layer of the atmosphere where weather occurs, is important
      to improving seasonal weather forecasts and predicting the effect of
      ozone depletion and global warming on our climate.

      ?The stratosphere has a longer ?memory? than the troposphere,? adds
      co-author Andrew Charlton. ?If you want to make forecasts on a time
      scale longer than several days, it is useful to understand the
      mechanisms linking places with longer memories, such as the
      stratosphere and the oceans to the troposphere.?

      The above map shows a snapshot of surface temperature in the Northern
      Hemisphere, with weather systems moving poleward. In the paper, the
      authors demonstrate that this process is influenced by the presence of
      a stratospheric jet.


      Each winter a westerly jet - called the Polar Night Jet - forms in the
      stratosphere. Winds in this jet circulate around the pole at speeds of
      up to 100 miles per hour. The strength of this jet changes as part of
      normal atmospheric variability, and possibly also in response to
      climate change. In their new research, the authors show that the
      presence of stronger westerly jets in the stratosphere causes
      tropospheric weather systems to track further towards the pole.

      Averaging the changes to the paths of weather systems, the research
      team showed, produces a pattern of changes similar in structure to the
      Arctic Oscillation, the dominant pattern of climate variability in the
      Northern Hemisphere that describes how temperatures across the whole
      hemisphere vary together.

      The research is part of the team?s ongoing efforts to understand the
      interaction of the stratosphere and troposphere and improve the
      representation of this interaction in climate models. The Columbia
      co-authors - Matthew Wittman, Lorenzo Polvani, Richard Scott and
      Andrew Charlton - are affiliated with the climate research group at
      the Earth Institute at Columbia.

      The Earth Institute at Columbia University is the world?s leading
      academic center for the integrated study of Earth, its environment and
      society. The Earth Institute builds upon excellence in the core
      disciplines - earth sciences, biological sciences, engineering
      sciences, social sciences and health sciences - and stresses
      cross-disciplinary approaches to complex problems. Through research,
      training and global partnerships, it mobilizes science and technology
      to advance sustainable development, while placing special emphasis on
      the needs of the world?s poor. For more information, visit
      www.earth.columbia.edu.

      acing special emphasis on the needs of the world?s poor. For more
      information, visit www.earth.columbia.edu.

      Sonya PLoS Medicine

      The open-access general medical journal from the Public Library of
      Science

      Inaugural issue: Autumn 2004 Share your discoveries with the world.

      http://www.plosmedicine.org

      ---------------------------------

      --- End forwarded message ---
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