Yuk Yung, Peter Gao , Xi Zhang, David Crisp, and Charles G. Bardeen DPS 44 October 17 th , 2012

1. Generation of Aerosol Particles via Nucleation of Meteoric Dust and Cloud Upwelling in the Upper Haze of Venus Yuk Yung, Peter Gao, Xi Zhang, David Crisp, and Charles G. Bardeen DPS 44 October 17th, 2012

2. Observations: The Upper Haze is variable on the order of days Luz, D. et al. (2011) – 3.8 μm VIRTIS radiance maps of Polar Vortex

3. Observations: The Upper Haze is variable on the order of days Luz, D. et al. (2011) – 3.8 μm VIRTIS radiance maps of Polar Vortex Markiewicz, W. J. et al. (2007) – UV images from VMC of southern hemisphere

4. Observations: Upper Haze variability is variable Wilquet, V. et al. (2012) – Extinction profiles from solar occultations during mid 2007 (top) and early 2008 (bottom)

5. Observations: Upper Haze variability is variable Wilquet, V. et al. (2012) – Extinction profiles from solar occultations during mid 2007 (top) and early 2008 (bottom) Understanding the variability of the Upper Haze leads to insights on atmospheric dynamics, chemistry, and the interactions between the hazes and the clouds.

6. CARMA 3.0 • 1D aerosol microphysics + vertical transport model • Developed by Turco, R. P. et al.(1979) • Upgraded to version 3.0 by Bardeen, C. G. et al. (2011)

7. CARMA 3.0 • 1D aerosol microphysics + vertical transport model • Developed by Turco, R. P. et al.(1979) • Upgraded to version 3.0 by Bardeen, C. G. et al. (2011) Model Setup • Standard Venus atmosphere from Seiff, A. et al. (1985). • Sulfate/sulfur nuclei + sulfuric acid vapour production rates • from Imamura, T. and Hashimoto, G. L. (2001). • Eddy diffusion coefficient from Imamura, T. and Hashimoto, • G. L. (2001) and Hunten, D. M. et al. (1983). • Meteoric dust production profile from Kalashnikova, O. et al. • (2000). • Run for 107 seconds.

8. Results: Number density and particle size

9. Results: Number density and particle size Mode 2 Mode 1 Mode 2’ or 3?

10. Results: Gas concentration vs. data Radio Occultations SVP Model Results

11. Results: Number density vs. data LCPS

12. Results: Upper haze size distribution 78 km 88 km 81 km 93 km 84 km

13. Results: Upper haze size distribution 78 km 88 km 81 km 93 km 84 km Meteoric dust production only Both Sulfur nuclei production only

14. Results: Upper haze size distribution 78 km 88 km 81 km 93 km 84 km Meteoric dust production only Both Sulfur nuclei production only The Upper Haze appears to be a mix of particles nucleated in situ and upwelling cloud particles.

15. Results: A qualitative look at the 2 “modes” “Small mode” “Large mode”

16. Results: A qualitative look at the 2 “modes” “Small mode” “Large mode”

18. Results: Wind effects (preliminary)

19. Results: Wind effects (preliminary) Solid – Original distribution Dotted – After 105s of winds Dashed – 105s after end of winds

20. Conclusions

21. Conclusions CARMA 3.0 can reproduce fairly accurately the number density of aerosols vs. altitude, as detected by Pioneer Venus’ LCPS.

22. Conclusions CARMA 3.0 can reproduce fairly accurately the number density of aerosols vs. altitude, as detected by Pioneer Venus’ LCPS. Modes 1 and 2 can be seen in the resulting size distributions, with a possible mode 2’ or 3 at lower altitudes.

23. Conclusions CARMA 3.0 can reproduce fairly accurately the number density of aerosols vs. altitude, as detected by Pioneer Venus’ LCPS. Modes 1 and 2 can be seen in the resulting size distributions, with a possible mode 2’ or 3 at lower altitudes. The upper haze appears to be a mix of particles nucleated in situ and upwelling cloud particles.

24. Conclusions CARMA 3.0 can reproduce fairly accurately the number density of aerosols vs. altitude, as detected by Pioneer Venus’ LCPS. Modes 1 and 2 can be seen in the resulting size distributions, with a possible mode 2’ or 3 at lower altitudes. The upper haze appears to be a mix of particles nucleated in situ and upwelling cloud particles. Qualitatively splitting the equilibrium upper haze size distribution into a small and large mode results in number densities of the modes matching the data within a factor of 2-3.

25. Conclusions CARMA 3.0 can reproduce fairly accurately the number density of aerosols vs. altitude, as detected by Pioneer Venus’ LCPS. Modes 1 and 2 can be seen in the resulting size distributions, with a possible mode 2’ or 3 at lower altitudes. The upper haze appears to be a mix of particles nucleated in situ and upwelling cloud particles. Qualitatively splitting the equilibrium upper haze size distribution into a small and large mode results in number densities of the modes matching the data within a factor of 2-3. Transient winds lasting about a day can increase the number density of the upper haze by an order of magnitude and create multi-modal size distributions, matching the observations, at least qualitatively.

26. THE END Yuk Yung, Peter Gao, Xi Zhang, David Crisp, and Charles G. Bardeen DPS 44 October 17th, 2012

34. Imamura, T. and Hashimoto, G. L. (2001) Model Setup

35. Model Setup Kalashnikova, O. et al. (2000) Meteoric Dust Production Profile

36. Model Setup Seiff, A. et al. (1985)

37. Model Setup Seiff, A. et al. (1985)

38. Imamura, T. and Hashimoto, G. L. (2001) and Hunten, D. M. et al. (1983) Model Setup