Start Submission Become a Reviewer

Reading: A Lagrangian computation of stratosphere–troposphere exchange in a tropopause-folding event ...

Download

A- A+
Alt. Display

Original Research Papers

A Lagrangian computation of stratosphere–troposphere exchange in a tropopause-folding event in the subtropical Southern Hemisphere

Authors:

J. Meloen ,

Royal Netherlands Meteorological Institute (KNMI), PO Box 201, 3730 AE De Bilt, NL
X close

P. C. Siegmund,

Royal Netherlands Meteorological Institute (KNMI), PO Box 201, 3730 AE De Bilt, NL
X close

M. Sigmond

Royal Netherlands Meteorological Institute (KNMI), PO Box 201, 3730 AE De Bilt, NL
X close

Abstract

A new Lagrangian technique to calculate the air mass flux across potential vorticity (Q) surfaces has been used to perform a case study of a tropopause-folding event in the subtropical Southern Hemisphere. The flux is computed from the rate of change in Q along trajectories, which are calculated from ECMWF wind data. Because the tropopause can be defined as a Q surface, the method can be used for the calculation of stratosphere–troposphere exchange (STE). A large number of forward and backward trajectories were calculated, starting in the vicinity of the tropopause fold. This fold was observed during the TRACAS (TRAnsport of Chemical species Across the Subtropical tropopause) experiment at La Reunion (21°S, 55°E) in July 1998.With the Lagrangian method the cross tropopause air mass flux can be calculated for the different tropopause levels, that occur in case of a tropopause folding. The computed mass exchange is about — 20×1013 kg (i.e., downward) in 4.5 days, which is rather small compared to other (midlatitude) mass exchange studies. The ratio of the fluxes per unit of area in and outside of the fold is about 200 : 1. An indication of the accuracy of the calculated fluxes has been obtained with the help of the ozone soundings made during the TRACAS experiment.

How to Cite: Meloen, J., Siegmund, P.C. and Sigmond, M., 2001. A Lagrangian computation of stratosphere–troposphere exchange in a tropopause-folding event in the subtropical Southern Hemisphere. Tellus A: Dynamic Meteorology and Oceanography, 53(3), pp.368–379. DOI: http://doi.org/10.3402/tellusa.v53i3.12194
  Published on 01 Jan 2001
 Accepted on 20 Nov 2000            Submitted on 31 Jan 2000

References

  1. Baray , J.-L. , Daniel , V. , Ancellet , G. and Legras , B . 2000 . Planetary-scale tropopause folds in the Southern sub-tropics . Geophys. Res. Lett . 27 , 353 – 356 .  

  2. Danielsen , E. F . 1990 . In defense of Ertel’s potential vorticity and its general applicability as a meteorolo-gical tracer. J. Atmos. Sc i . 47 , 2013 – 2020 .  

  3. Folkins , I. and Appenzeller , C . 1996 . Ozone and potential vorticity at the subtropical tropopause break. J. Geo-phys . Res . 101 , D13 , 18787 – 18792 .  

  4. Gouget , H. , Cammas , J.-P. , Marenco , A. , Rosst , R. and Jonquierès , I . 1996 . Ozone peaks associated with a subtropical tropopause fold and with the trade wind inversion: a case study from the airborne campaign TROPOZ II over the Caribbean in winter . J. Geophys. Res . 101 , 25979 – 25993 .  

  5. Grewe , V. and Damaris , M . 1995 . Calculating the global mass exchange between stratosphere and troposphere . Ann. Geophysicae 14 , 431 – 442 .  

  6. Haynes , P. H. and McIntyre , M. E . 1990 . On the conser-vation and impermeability theorems for potential vor-ticity . J. Atmos. Sci . 47 , 2021 – 2031 .  

  7. Holton , J. R. , Haynes , P. H. , McIntyre , M. E. , Douglass , A. R. , Rood , R. B. and Pfister , L . 1995 . Stratosphere—troposphere exchange . Rev. Geophys . 33 , 403 – 439 .  

  8. Lamarque , J. and Hess , P. G . 1994 . Cross-tropopause mass exchange and potential vorticity budget in a simulated tropopause folding . J. Atmos. Sci . 51 , 2246 – 2269 .  

  9. Petterssen , S . 1940 . Weather analysis and forecasting . McGraw-Hill Book Company , Inc ., pp. 221 – 223 .  

  10. Plumb , R. A. and Ko , M. K. W . 1992 . Interrelationships between mixing ratios of long-lived stratospheric con-stituents . J. Geophys. Res . 97 , 10145 – 10156 .  

  11. Ramond , D. , Corbin , H. , Desbois , M. , Szejwach , G. and Waldteufel , P. 1981 . The dynamics of polar jet stream as depicted by the Meteosat WV Channel radiance Fields. Mon. Wea. Rev . 109 , 2164 – 2176.  

  12. Ravetta , F. , Ancellet , G. , Kowol-Santen , J. , Wilson , R. and Nedeljkovic , D . 1999 . Ozone, temperature, and wind field measurements in a tropopause fold: compa-rison with a mesoscale model simulation . Mon. Wea. Rev . 127 , 2641 – 2653 .  

  13. Reiter , E. R. and Mahlman , J. D . 1965 . Heavy radioactive fallout over the southern United States, November 1962 . J. Geophys. Res . 70 , 4501 – 4520 .  

  14. Reiter , E. R. , Glasser , M. E. and Mahlman , J. D . 1969 . The role of the tropopause in stratospheric—tropo-spheric exchange process . Pure Appl. Geophys . 75 , 185 – 218 .  

  15. Scheele , M. P. , Siegmund , P. C. and van Velthoven , P. F. J . 1996 . Sensitivity of trajectories to data reso-lution and its dependence on the starting point: in or outside a tropopause fold . Meteorol. Appl . 3 , 267 – 273 .  

  16. Shapiro , M. A . 1980 . Turbulent mixing within tropo-pause folds as a mechanism for the exchange of che-mical constituents between the stratosphere and troposphere . J. Atmos. Sci . 37 , 994 – 1004 .  

  17. Siegmund , P. C. , van Velthoven , P. F. J. and Kelder , H . 1996 . Cross-tropopause transport in the extratropical northern winter hemisphere, diagnosed from high-resolution ECMWF data . Q. J. R. Meteorol. Soc . 122 , 1921 – 1941 .  

  18. Sigmond , M. , Meloen , J. and Siegmund , P. C . 2000 . Stratosphere—troposphere exchange in an extratropi-cal cyclone, calculated with a Lagrangian method . Ann. Geophysicae 18 , 573 – 582 .  

  19. Stohl , A. and Seibert , P . 1998 . Accuracy of trajectories as determined from the conservation of meteorological tracers . Q. J. R. Meteorol. Soc . 124 , 1465 – 1484 .  

  20. Vaughan , G. , Price , J. D. and Howells , A . 1994 . Transport into the troposphere in a tropopause fold . Q. J. R. Meteorol. Soc . 120 , 1085 – 1103 .  

  21. Wei , M.-Y . 1987 . A new formulation of the exchange of mass and trace constituents between the stratosphere and troposphere . J. Atmos. Sci . 44 , 3079 – 3086 .  

  22. Wirth , V. and Egger , J . 1999 . Diagnosing extratropical synoptic scale straexchange: a case study . Q. J. R. Meteorol. Soc . 125 , 635 – 655 .  

comments powered by Disqus