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Simone Tilmes, Laura Pan, Louisa Emmons, Hans Schlager, START08 team, ARCTAS team, GRACE team

Seasonal Differences of UTLS Exchange Processes between Spring and Summer in the Subtropics and Polar Region. Simone Tilmes, Laura Pan, Louisa Emmons, Hans Schlager, START08 team, ARCTAS team, GRACE team. UTLS Workshop, October19-22, 2009. Overview. Aircraft data used (O 3 and CO)

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Simone Tilmes, Laura Pan, Louisa Emmons, Hans Schlager, START08 team, ARCTAS team, GRACE team

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  1. Seasonal Differences of UTLS Exchange Processes between Spring and Summer in the Subtropics and Polar Region Simone Tilmes, Laura Pan, Louisa Emmons, Hans Schlager, START08 team, ARCTAS team, GRACE team UTLS Workshop, October19-22, 2009

  2. Overview • Aircraft data used (O3 and CO) • Method to divide the Extra-Tropics into Sub-Tropics and Polar Region • Differences in Tracer Characteristics • Differences in Exchange/Mixing Processes using Tracer-Tracer Correlations • Connection between the stability of the atmosphere and exchange characteristics in the polar region

  3. Aircraft Data STRAT-POLARIS; START08; POLARCAT: ARCTAS/GRACE, April to July 2008 Altitude (km) Latitude

  4. Definition of Regions based on the Tropopause Height dΦ/dz (K/km) EQ EQ Pol Pol

  5. Definition of Regions based on the Tropopause Height dΦ/dz (K/km) Sub-Tropics Sub-Tropics Polar- Region Polar- Region Tropics Tropics EQ EQ Pol Pol Tropics: TP > 365 K pot. Temp. Subtropics: 325 K < TP < 365 K, Winter/Spring 335 K < TP < 365 K, Summer/Fall plus: double TP events Polar Region: TP > 325 K, Winter/Spring TP > 335 K, Summer/Fall Sub-Tropics: Region influence by frequent exchange with the Tropics Polar Region: Region influenced by exchange across the local Tropopause

  6. Tracer Characteristics in Subtropics and the Polar Region Subtropics Polar Region Spring Summer

  7. Relative Altitude /Ozone Subtropics Polar Region Spring Summer Subtropics: Bi-model distribution in 0-4km above the Tropopause wider distribution in Spring than in summer Polar Region: distribution is more compact especially in spring compared to the Subtropics

  8. Relative Altitude /CO Subtropics Polar Region Spring Summer Subtropics: Bi-model distribution in 0-4km above the Tropopause larger surface values in Spring than in summer Polar Region: influence of convection and long-range transport

  9. O3/CO Correlations Subtropics Polar Region Spring Summer Region of mixing identified using tracer-tracer correlations Stratospheric branch: fit of profiles O3 > 600 ppbv and CO < 35ppbv Tropospheric branch: fit of profiles < 100 ppbv

  10. Different Regions of Mixing above 365 K above the TP; below 365 K below the TP EQ Pol Subtropics dΦ/dz (K/km) O3 (ppbv) CO (ppbv)

  11. Different Regions of Mixing above 365 K above the TP; below 365 K below the TP Subtropics O3 (ppbv) CO (ppbv)

  12. Mixed data above 365 K above the TP; below 365 K below the TP Subtropics O3 (ppbv) CO (ppbv)

  13. Mixed data above 365 K above the TP; below 365 K below the TP Subtropics O3 (ppbv) CO (ppbv)

  14. Mixed data above 365 K above the TP; below 365 K below the TP Subtropics Ozone CO Spring Summer

  15. Mixed data above 365 K above the TP; below 365 K below the TP Subtropics Ozone CO Fraction of samples Relative Altitude (km)

  16. Mixed data above 365 K above the TP; below 365 K below the TP Polar Region

  17. Mixed data above 365 K above the TP; below 365 K below the TP Polar Region Spring Summer

  18. Mixed data above 365 K above the TP; below 365 K below the TP Polar Region Fraction of samples convection Relative Altitude (km) Schlager et al., in preparation

  19. Transition Region in Spring, Polar Region Mixed data above 365 K above the TP; below 365 K below the TP Fraction of samples Can we understand the with of the transition region and the distribution? Relative Altitude (km)

  20. Case Study: ARCTAS April 09, 2008 dΦ/dz (K/km)

  21. Case Study: ARCTAS April 09, 2008 dΦ/dz (K/km) We need to explore the frequency of enhanced/reduced static stability below/above the TP to quantify the location of thickness of the transition layer

  22. Summary:Depth of the transition layer Mixed data above 365 K above the TP; below 365 K below the TP Fraction of samples Relative Altitude (km)

  23. Conclusions Results show: • characteristic tracer behavior in each region • seasonal and regional differences in exchange processes and width of the tropopause • seasonal differences are less pronounced • extended climatology is used within the CCMVAl diagnostics Further work: • an extended set of aircraft observations is desired, especially for the polar regions to support these results • model data will be used in future studies to elaborate the representativeness of a limited set of aircraft data used

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