1. 1 OWP5: SCOUT balloons (Stratosphere-Climate links with emphasis on the UTLS) Andrew Robinson Centre for Atmospheric Science, Cambridge University, Cambridge, UK adr22@cam.ac.uk

2. 2 Cambridge Centre for Atmospheric Science Halocarbon Measurement Group A. D. Robinson (1), B. Gostlow (1), N. R. P. Harris (1,2), J. A. Pyle (1,3) (1) Centre for Atmospheric Science, Cambridge University, Cambridge, UK (2) European Ozone Research Coordinating Unit, Cambridge, UK (3) NCAS-ACMSU, Cambridge University, Cambridge, UK adr22@cam.ac.uk http://www.atm.ch.cam.ac.uk/~halocarbon/

3. 3 Content Introduction: halocarbon group Balloon options in AMMA (Summer 2006) Slow descent balloons Example results from HIBISCUS Short lived tracers with  Dirac Conclusion

4. 4 Halocarbon group instruments DESCARTES grab samplers DIRAC in situ isothermal GC-ECD  DIRAC in situ programmed GC-ECD

5. 5 3SF balloon (24 Feb 2004, Bauru, Brazil) Balloon options in AMMA / SCOUT O 3 Ballooning phase of SCOUT O 3 from West Africa Summer 2006 (current plan) Two balloon flights funded (plans for at least 2 more) 3SF (3000 m 3 ) balloons with slow night- time descent through TTL (preferred option) 10ZL (10000 m 3 ) balloons with parachute descent from 25-30 km

6. 6 3SF balloon flight data (13 Feb 2003, Bauru, Brazil) Slow descent balloons 3SF balloon model data (courtesy: G. Letrenne, CNES)

7. 7 TTL Long lived tracer profile (DIRAC CFC-11) No significant drop below 430 K, 19 km (vertical transport very slow above this level?) Ozone increase begins inside the TTL Slightly higher CFC-11 values around 360 K (horizontal transport?) Ozone data courtesy of Graeme Hansford Example results: HIBISCUS (24 Feb 2004)

8. 8 Example results: HIBISCUS (TTL) Long lived tracer (CFC-113): low inter-flight variability near zero gradient across TTL Short lived tracers: more intra-flight / inter-flight variability larger gradient across TTL (except chloroform on SF2)

9. 9 Short lived tracers with  Dirac Target short lived tracers for AMMA / SCOUT O3: Biogenic: CH 3 I (~7d), CHBr 3 (~26d), CH 2 Br 2 (~120d), CH3Br ? Industrial: C 2 HCl 3 (~5d), CHCl 3 (~150d), C 2 Cl 4 (~100d)

10. 10 Conclusions AMMA / SCOUT O 3 aiming for summer 2006 Slow descent balloons flights (preferred option) Two flights funded (2 more?)  Dirac preferred instrument Target gases: short lived (some long lived) Lifetime range: 5 days to 80 years Acknowledgements: Many thanks to NERC, EC (HIBISCUS), TrroCCiBras