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Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018

Journal Article


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Abstract


  • ©2020. American Geophysical Union. All Rights Reserved. Total columns of the trace gases nitric acid (HNO3) and hydrogen chloride (HCl) are sensitive to variations in the lower stratospheric age of air, a quantity that describes transport time scales in the stratosphere. Analyses of HNO3 and HCl columns from the Network for the Detection of Atmospheric Composition Change panning 77°S to 79°N have detected changes in the extratropical stratospheric transport circulation from 1994 to 2018. The HNO3 and HCl analyses combined with the age of air from a simulation using the MERRA2 reanalysis show that the Southern Hemisphere lower stratosphere has become 1 month/decade younger relative to the Northern Hemisphere, largely driven by the Southern Hemisphere transport circulation. The analyses reveal multiyear anomalies with a 5- to 7-year period driven by interactions between the circulation and the quasi-biennial oscillation in tropical winds. This hitherto unrecognized variability is large relative to hemispheric transport trends and may bias ozone trend regressions.

Authors


  •   Strahan, Susan (external author)
  •   Smale, Dan (external author)
  •   Douglass, Anne (external author)
  •   Blumenstock, Thomas (external author)
  •   Hannigan, James (external author)
  •   Hase, Frank (external author)
  •   Jones, Nicholas B.
  •   Mahieu, Emmanuel (external author)
  •   Notholt, Justus (external author)
  •   Oman, Luke (external author)
  •   Ortega, Ivan (external author)
  •   Palm, Mathias (external author)
  •   Prignon, Maxime (external author)
  •   Robinson, John (external author)
  •   Schneider, Matthias (external author)
  •   Sussmann, Ralf (external author)
  •   Velazco, Voltaire A.

Publication Date


  • 2020

Citation


  • Strahan, S., Smale, D., Douglass, A., Blumenstock, T., Hannigan, J., Hase, F., Jones, N., Mahieu, E., Notholt, J., Oman, L., Ortega, I., Palm, M., Prignon, M., Robinson, J., Schneider, M., Sussmann, R. & Velazco, V. (2020). Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018. Geophysical Research Letters, 47 (17),

Scopus Eid


  • 2-s2.0-85090864220

Ro Full-text Url


  • https://ro.uow.edu.au/cgi/viewcontent.cgi?article=2641&context=smhpapers1

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers1/1607

Volume


  • 47

Issue


  • 17

Place Of Publication


  • United States

Abstract


  • ©2020. American Geophysical Union. All Rights Reserved. Total columns of the trace gases nitric acid (HNO3) and hydrogen chloride (HCl) are sensitive to variations in the lower stratospheric age of air, a quantity that describes transport time scales in the stratosphere. Analyses of HNO3 and HCl columns from the Network for the Detection of Atmospheric Composition Change panning 77°S to 79°N have detected changes in the extratropical stratospheric transport circulation from 1994 to 2018. The HNO3 and HCl analyses combined with the age of air from a simulation using the MERRA2 reanalysis show that the Southern Hemisphere lower stratosphere has become 1 month/decade younger relative to the Northern Hemisphere, largely driven by the Southern Hemisphere transport circulation. The analyses reveal multiyear anomalies with a 5- to 7-year period driven by interactions between the circulation and the quasi-biennial oscillation in tropical winds. This hitherto unrecognized variability is large relative to hemispheric transport trends and may bias ozone trend regressions.

Authors


  •   Strahan, Susan (external author)
  •   Smale, Dan (external author)
  •   Douglass, Anne (external author)
  •   Blumenstock, Thomas (external author)
  •   Hannigan, James (external author)
  •   Hase, Frank (external author)
  •   Jones, Nicholas B.
  •   Mahieu, Emmanuel (external author)
  •   Notholt, Justus (external author)
  •   Oman, Luke (external author)
  •   Ortega, Ivan (external author)
  •   Palm, Mathias (external author)
  •   Prignon, Maxime (external author)
  •   Robinson, John (external author)
  •   Schneider, Matthias (external author)
  •   Sussmann, Ralf (external author)
  •   Velazco, Voltaire A.

Publication Date


  • 2020

Citation


  • Strahan, S., Smale, D., Douglass, A., Blumenstock, T., Hannigan, J., Hase, F., Jones, N., Mahieu, E., Notholt, J., Oman, L., Ortega, I., Palm, M., Prignon, M., Robinson, J., Schneider, M., Sussmann, R. & Velazco, V. (2020). Observed Hemispheric Asymmetry in Stratospheric Transport Trends From 1994 to 2018. Geophysical Research Letters, 47 (17),

Scopus Eid


  • 2-s2.0-85090864220

Ro Full-text Url


  • https://ro.uow.edu.au/cgi/viewcontent.cgi?article=2641&context=smhpapers1

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers1/1607

Volume


  • 47

Issue


  • 17

Place Of Publication


  • United States