1. UVIS Saturn EUVFUV Data Analysis*
07/16/96
UVIS Saturn EUVFUV Data Analysis
R. West and D. Tice *

2. Nine EUVFUV sets Row -> Integration number ->*
07/16/96
Nine EUVFUV sets
Row ->
Integration number ->
Flat field corrections
Residual vertical striping is apparent *

3. Data Reduction Cube Generator (includes flat field)*
07/16/96
Data Reduction
Cube Generator (includes flat field)
Image geometry is a product
Divide by a solar spectrum processed by D. Shemansky’s simulator software to get I/F
There is a slope issue here.
Subtract a background from off-planet pixels
Extract data in a latitude band and fit to Minneart function to improve signal/noise *

4. Selection of Pixels in a Latitude Band
Deg.

5. *
07/16/96
Minneart Fit *

6. Geometry Corrections Identify four edges of planet based on geometry
Pixels with valid longitude values are assumed to be ‘on-planet’
Identify four edges of planet based on I/F values.
Points are assumed ‘on-planet’ where either condition is met:
high signal to noise ratio (for Ang. composite image)
low signal to noise ratio (within the Lyman-Alpha band)

7. Sample of Results:
022SA_2006_ SA_2006_063

8. Model Å
Multiple Scattering radiative transfer, including polarization
Rayleigh scattering by molecular H2 and He
Absorption and scattering by aerosols
Absorption by (mainly) C2H2, PH3, other hydrocarbons
Gas profiles from Moses et al. (2000) and Prange et al

9. Relevant Absorbers (from Prangé et al., 2005)

10. Profiles from Moses et al., 2000

11. Sample Fits Model 42 Example

12. Low Phase, Center/Limb Behavior
Strong center/limb differences not matched by model. Model acetylene features have smaller amplitude than observed. Slope between 1600 and 1700 Angstroms not well matched

13. Center-To-Limb Behavior

14. Phase Angle Dependence
Relatively good fit to high phase and to limb at low phase but not to central meridian at low phase suggests acetylene profile needs to decrease at depth but not at high altitude. Not obvious this will fix the problem. No evidence for high altitude aerosol scattering. Need to deconvolve in the spatial domain?

15. Status Report on Saturn Models
Continuing to add new data sets – will lead to better coverage of the northern hemisphere.
These data provide [too] many constraints on the models – (absolute I/F spectra from nm, limb-darkening at all wavelengths, phase behavior). A successful solution to all these has yet to be found.
Large difference (from other observations/models) implied for C2H4 and possibly for deep C2H2.
Residual questions about calibration/method (including temperature dependence of absorption coefficients) and need to deconvolve must be addressed.

16. Backup Material

17. Prangé et al. Data and Model
Our calculation
Prangé paper

18. CIRS Results
Fouchet presentation

19. References
Moses, J. et al., ‘Photochemistry of Saturn’s Atmosphere I. Hydrocarbon Chemistry and Comparisons with ISO Observations’, Icarus 143, 244–298 (2000)
Prangé, R. et al., ‘Latitudinal variation of Saturn photochemistry deduced from spatially-resolved ultraviolet spectra’, Icarus 180, (2005).

20. UVIS Extended Mission – Saturn and Titan
Solar Occultations
Stellar Occultations
Auroral Mapping (Wayne Pryor)
Other mapping (EUVFUV) for hydrocarbon chemistry

21. Saturn and Titan Solar Occultations

22. Saturn – Solar Occultations
Fro Don Shemansky

23. Saturn Stellar Occs in the XM
Rev 87 Alp Cru Latitude -19
Rev 97 Alp Cru Latitude +1.3
Rev 97 Bet Cen Latitude +19
Full table..\..\Desktop\Folders and files\PF6h9 Occultations

24. Titan Stellar Occs in the XM
Chronological order
Sorted by latitude

25. Titan EUVFUV in XM T Phase rev C/A +5 or -5 hours
Most are 7 hr. duration (2-9 hr. from C/A)
Template P
* Ends at -5 to accommodate Radar (template P)

26. Extended Mission – Saturn and Titan
Solar Occultations
Saturn Working Group Presentation by Scott Edgington