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Dynamical Influence on Inter-annual and Decadal Ozone Change

Dynamical Influence on Inter-annual and Decadal Ozone Change. Sandip Dhomse, Mark Weber, J.P. Burrows Universtät Bremen FB1 , Insti tüt für Umweltphysik (iup). sandip@iup.physik.uni-bremen.de. http://www.iup.physik.uni-bremen.de. Outline Introduction Data used Inter-annual variability

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Dynamical Influence on Inter-annual and Decadal Ozone Change

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  1. Dynamical Influence on Inter-annual and Decadal Ozone Change Sandip Dhomse, Mark Weber, J.P. Burrows UniverstätBremen FB1, Institüt für Umweltphysik (iup) sandip@iup.physik.uni-bremen.de http://www.iup.physik.uni-bremen.de

  2. Outline • Introduction • Data used • Inter-annual variability • Decadal variability • Tele-connection patterns (Introduction) • Summary and Conclusion • Outlook sandip@iup.physik.uni-bremen.de 11/11/03

  3. Introduction Sun - at the same position No abrupt change in chemical composition sandip@iup.physik.uni-bremen.de 11/11/03

  4. Low TOZ In tropics Relatively High TOZ in tropics during SH spring Total Ozone is higher in NH (spring) than SH (spring) sandip@iup.physik.uni-bremen.de 11/11/03

  5. Wave activity controls • Stratospheric circulation • Stratosphere Troposphere Exchange Holton et al., 1995 sandip@iup.physik.uni-bremen.de 11/11/03

  6. Mean Winter temp. (shaded) And zonal wind (contour) for NH and SH SH – polar jet stronger SH winter- colder Tropopause colder during NH winter sandip@iup.physik.uni-bremen.de 11/11/03

  7. Planetary waves Planetary waves are large-scale distortions to the mean flow The flow (black) meanders across latitude circles (blue). V V sandip@iup.physik.uni-bremen.de 11/11/03

  8. Examples of wave patterns Wave 1 pattern Wave 2 pattern sandip@iup.physik.uni-bremen.de 11/11/03

  9. Brewer-Dobson circulation • Breaking planetary waves apply a FORCE to the winds- decelerates the speed • Pressure gradient force- remains unaffected • Corioli’s force - REDUCED so there is a net force towards the pole. • Air RISES over the equator, drifts steadily POLEWARD (while meandering around the latitude circles) and SINKS at the poles sandip@iup.physik.uni-bremen.de 11/11/03

  10. Measuring the wave activity • Eliassen Palm (EP) flux vector is a measure of the upward propagating momentum carried by planetary waves • The divergence of EP flux gives the volume where momentum is deposited Momentum flux Two components of EP flux are calculated as,(Andrews,et.al 1987) And its divergence is Heat flux sandip@iup.physik.uni-bremen.de 11/11/03

  11. Measuring the wave activity sandip@iup.physik.uni-bremen.de 11/11/03

  12. sandip@iup.physik.uni-bremen.de 11/11/03

  13. Data used Meteorological data set • ERA40 - 23 pressure levels • ERA15 - 17 pressure levels • UK Met. Office - 22 pressure levels • ECMWF - 21 pressure levels • NCEP - 17 pressure levels Ozone data set • GOME - total ozone data • TOMS - total ozone data sandip@iup.physik.uni-bremen.de 11/11/ 03

  14. Inter-annual variation of flux and Ozone High flux- increase in Brewer-Dobson circulation - more transport sandip@iup.physik.uni-bremen.de 11/11/ 03

  15. First major stratospheric warming in SH Splitting of the polar vortex on 26th September 2002 Record high lower stratospheric heat flux on 20th/21st September (ERA40 1960-2002) sandip@iup.physik.uni-bremen.de 11/11/ 03

  16. wave activity and winter gain in ozone Weber et al. 2003 • High correlation between winter heat flux (wave activity) and spring/fall ozone ratio • Winter ozone gain in Antarctic 2002 presents an intermediate case between other Antarctic winters and cold Arctic winters (higher contribution from transport) sandip@iup.physik.uni-bremen.de 11/11/ 03

  17. High Heat flux –Low PSC

  18. Model Differences ERA40 Does dynamics the same? Or Chemistry is changing? ERA40 +ERA15 sandip@iup.physik.uni-bremen.de 11/11/ 03 sandip@iup.physik.uni-bremen.de 11/11/ 03

  19. Decadal Variation? And Difficulties in trend analysis sandip@iup.physik.uni-bremen.de 11/11/ 03

  20. Northern Hemisphere sandip@iup.physik.uni-bremen.de 11/11/ 03

  21. Tropics (50 hPa) One of longest westerly phases of QBO (1993-1996) sandip@iup.physik.uni-bremen.de 11/11/ 03

  22. tropics Mid-latitudes Polar sandip@iup.physik.uni-bremen.de 11/11/ 03

  23. -1.2 K/decade in Nov. and Dec. No SSW since last 17 years in Jan. sandip@iup.physik.uni-bremen.de 11/11/ 03

  24. SH – pre-satellite period – Problem? sandip@iup.physik.uni-bremen.de 11/11/ 03

  25. PSC volume using ERA40 data NH (JUL-JUN) SH (JAN-DEC) T <195 K (PSC volume) sandip@iup.physik.uni-bremen.de 11/11/ 03

  26. Days (Jan-Dec) Days (Jul-Jun) 195 K- PSC temperature SH –colder temperature sandip@iup.physik.uni-bremen.de 11/11/ 03

  27. No significant trend in heat flux sandip@iup.physik.uni-bremen.de 11/11/ 03

  28. Different models – different trends sandip@iup.physik.uni-bremen.de 11/11/ 03

  29. No significant trend in any dataset in heat flux as well as EP Flux sandip@iup.physik.uni-bremen.de 11/11/ 03

  30. Summary • Strong correlation between seasonal heat flux and total ozone in March. • No significant trend on seasonal scale in heat flux. • Maximum cooling trend is in November and January ( -1.2 K/decade) , but there is not trend in heat flux. • Different models, different periods lead to different trends. sandip@iup.physik.uni-bremen.de 11/11/03

  31. Bremen- 10/23/2003 sandip@iup.physik.uni-bremen.de 11/11/03

  32. Arctic Oscillation sandip@iup.physik.uni-bremen.de 11/11/03

  33. Arctic Oscillation From National Geographic Magazine March-2000 sandip@iup.physik.uni-bremen.de 11/11/03

  34. Arctic Oscillation sandip@iup.physik.uni-bremen.de 11/11/03 source : http://www.ldeo.columbia.edu

  35. 28% 45% 30% sandip@iup.physik.uni-bremen.de 11/11/03

  36. 12 % 13% 25% sandip@iup.physik.uni-bremen.de 11/11/03

  37. 8% 11% 8% sandip@iup.physik.uni-bremen.de 11/11/03

  38. Conclusion • There are no significant trends in 2D (latitude & altitude) analysis of the data. • 3D analysis of data will be useful to find the dependence of ozone on different tele-connection patterns. • EOF analysis is good tool for 3D analysis. sandip@iup.physik.uni-bremen.de 11/11/03

  39. Outlook • Study ozone dependence on different tele-connection pattern using EOF technique. • Find out different patterns in the ozone variability using GOME vertical profile data (neural network) , TOMS, SAGE, POAM, ozonesonde datasets. sandip@iup.physik.uni-bremen.de 11/11/03

  40. Thank you very much for your kind attention!!! sandip@iup.physik.uni-bremen.de 11/11/03

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